Use Of Grooves Research Articles

Modeling of defects in ultrasonic flaw detection. Status and prospects

In the introduction to the article four factors, which are most important for ensuring the accuracy of defect parameters measurements at ultrasonic inspection, are mentioned: parameters of artificial reflectors in samples, compliance of acoustic properties of material of tuning samples and controlled products, transient characteristics of electroacoustic paths, methodological features of measurements. The present article is devoted to the analysis of the first and partly fourth of listed factors. The review of reflectors, the use of which is regulated in various standards, is carried out. Advantages and disadvantages of flat-bottomed holes, segmental and angular reflectors (“notches”), lateral (BCO) and vertical cylindrical drills, grooves are noted. Taking into account the peculiarities of ultrasonic wave scattering, it is noted that artificial “reflectors” such as “grooves” and BCOs are used to adjust the parameters of modern diffraction control methods. It is recommended to expand the use of grooves, BCO and vertical drilling in the revision of standards governing the use of classical echo-methods. The estimation of accuracy of measurement of defects parameters, first of all — coordinates of crack tip, with application of modern digital methods of information processing at ultrasonic control is given. It is indicated that to increase the accuracy of measurements, to determine the position and orientation of cracks in welds, it is necessary to create a database of digital doubles of samples with artificial reflectors and products with real defects. The general scheme of quality control work execution is given, taking into account the use of standards (measures), digital models of artificial reflectors and digital twins of the control process to ensure the necessary detectability of defects and reliability of manual, automated and, potentially, automatic control.

A text mining approach to the use of “groove” in everyday language

When speaking about music, the term groove can refer to objective qualities, such as rhythmic patterns, or to subjective experiences, such as the pleasurable urge to move to the music. However, the mere juxtaposition of objective musical causes and subjective psychological effects may be too simplistic to fully capture the multifaceted groove phenomenon. We therefore broaden the perspective of groove research by analyzing how people use the term groove in the everyday language of 970,220 comments on 155 YouTube music videos. The corresponding songs were previously rated on groove, operationalized as a pleasurable urge to move. Results show that groove terms were more likely to be used in comments on songs that received higher groove ratings. Resonating with the definition of groove as a pleasurable urge to move, groove terms were very likely to co-occur with movement terms, and comments mentioning groove expressed more positive sentiments. We also found that groove terms were predominantly used to describe objective musical qualities in comments on funk, soul, and R&B songs, suggesting that the use of groove is related to genre. In general, we demonstrate how text mining can be used to review existing definitions and gain new perspectives on current topics in music science.

Horizontal Chimney Effect

Abstract An analysis of natural convection in horizontal slots has been carried out. It is demonstrated that a proper combination of heating and groove patterns can create a net horizontal fluid movement, which we refer to as the horizontal chimney effect. Groove shapes that can be easily manufactured as well as heating patterns that can be easily created using heating wires were considered. It has been shown that both patterns must be properly tuned. The direction of the net horizontal flow can be changed by changing the relative positions of the patterns. Changes of groove geometry can change the flow rate by up to 100%. Simultaneous use of grooves and heating at both plates can nearly double the system effectiveness. The strength of the flow increases with reduction of the Prandtl number.

Influence of different surface treatments on the shear strength between acrylic resin and two materials: Polyether Ether Ketone (PEEK) / ZANTEXR

The present study assesses the shear strength of Polyether Ether Ketone (PEEK) and Zantex to thermopolymerizable acrylic resin (TAR) with different surface treatments. To this end, 100 test specimens were produced and divided into two groups: G1(PEEK + TAR) and G2 (Zantex + TAR). Each group was subdivided into the subgroups A, B, C, D and E (n=10) according to surface pre-treatment: A: TAR + PEEK/Zantex without surface treatment (control); B: TAR + PEEK/Zantex treated with Palabond; C: TAR + PEEK/Zantex blasted with aluminum oxide (Al2O3) of 125 µm; D: TAR + PEEK /Zantex treated with Al2O3 of 125 µm + Palabond; and E: TAR + PEEK/Zantex prepared with groove-shaped retentions. The structures were tested in a Universal testing machine EMIC DL2000. Two-way variance analysis showed significant difference between materials and surface treatments (p < 0.001). Multiple comparisons were done with Tukey’s test and failure modes were analyzed with the G test. Statistical analysis showed that Zantex outperformed PEEK for most treatments and showed similar performance in the subgroups treated with Al2O3. Within the PEEK group, the use of grooves and Palabond combined with blasting showed the best results; in the Zantex group, the best results were obtained with Palabond and Palabond combined with blasting. Regarding failure modes, PEEK showed only adhesive failures and Zantex’s failures were dependent on treatment. Therefore, the surface treatment method applied to the polymers studied here contribute to the material’s adhesion to acrylic resin.

Determining the effect of nozzle groove on the fluid flow through viscous 2D planar fluid

The study aims to determine the effect of the nozzle groove on fluid flow through the viscous 2D planar fluid. To fulfil the study's aim, a numerical method was adopted to introduce grooves of different dimensions from the nozzle exit. The study adopts SolidWorks software that was used to design nozzles and introduce groove shaped nozzles, each consisting of six different designs. The nozzle base model used in this study was similar to the one used in a previous study. The procedure was performed with different pressures (8, 10, and 12 bar) at a similar firefighting nozzle. The velocities contours were predicted based on the choice of nozzle section during the numerical stimulation. The present study results demonstrated a new approach that can be used for the increasing velocity at various types of modified nozzles through grooves at different pressures and locations. For grooves, dimensions 1×1 (mm) and location 15 mm at 8 bar, 10 bar and 12 bars showed no effect on velocity as it reduces velocity by increasing surface area. The velocity increases with increasing pressure in the proportion relationship. It clearly explains that the groove does not affect velocity as it rises due to increase in pressure. It is because the groove reduces the velocity by increasing surface area. The study concludes that the use of groove increases the velocity of water that further improves nozzles operation.

Temperature rise of journal bearing of the high-speed circular arc gear pump

A “circular arc–involute–circular arc” circular arc gear pump was developed based on a gear meshing principle and coordinate transformation as well as an accurate calculation model of the radial force. The dependence of the radial force on the meshing angle was investigated. The temperature rise of journal bearings in the pump was evaluated for bearings with and without herringbone grooves. Furthermore, the influence of the rotational speed and outlet pressure on this rise was assessed. The results revealed using herringbone groove on the inner wall of bearing was effective in reducing the temperature increase. Therefore, the use of grooves represents a suitable method of reducing the temperature rise in the journal bearings of a high-speed gear pump.

HEAT TRANSFER ENHANCEMENT AND PRESSURE DROP OF GROOVED ANNULUS OF DOUBLE PIPE HEAT EXCHANGER

This investigation was performed to experimentally investigate the enhancement of heat transfer and the friction of an annulus in a double pipe heat exchanger system with rectangular grooves in the turbulent flow regime. The shell is made of acrylic and its diameter is 28 mm. The tube is made of aluminium and its diameter is 20 mm. Grooves were incised in the annulus room with a circumferential pattern, with a groove space of 2 mm, a distance between the grooves of 8mm and a groove height of 0.3 mm. The experiments consist of temperature and pressure measurement and a flow visualization. Throughout the investigation, the cold fluid flowed in the annulus room. The Reynold number of cold fluid varied from about 31981 to 43601 in a counter flow condition. The volume flow rate of hot fluid remains constant with Reynold number about 30904. Result showed the effect of grooves, which are applied in the annulus room. The grooves induce the pressure drop, the pressure drop in the grooved annulus was greater by about 15.88% to 16.72% than the one in the smooth annulus. The total heat transfer enhancement is of 1.09–1.11. Moreover, the use of grooves in the annulus of the heat exchanger not only increase the heat transfer process, but also increase the pressure drop, which is related to the friction factor.

ЕКСПЕРИМЕНТАЛЬНІ ДОСЛІДЖЕННЯ МОЖЛИВОСТЕЙ ІНТЕНСИФІКАЦІЇ ТЕПЛООБМІНУ ПРИ ПАРОУТВОРЕННІ НА МІКРОКАНАЛЬНИХ ПОВЕРХНЯХ

The use of grooves, as the structure of flat plate heat pipe is widespread and is a popular and effective technical solution in the practical implementation of various design systems for thermal control of electronic equipment. Advanced thermal control system must meet two criteria: 1) have a high heat transfer coefficient; 2) remove heat of high density. However, the last criterion leads to the fact that the high density heat flux may lead to a boiling limit, which leads to a drastic decrease in heat transfer coefficient, and conducts to a rapid increase of surface temperature. The paper presents an experimental investigation of the heat transfer characteristics of the microgrooved structures at vaporization of water and ethanol. The structures are represented in the form of axial grooves with a square section dimensions of 0.3, 0.5 and 0.7 mm, and a rectangular cross section with the same width and pitch parameters of the channel but with double depth of channels. Studies showed that in the grooved structures three modes of vaporization occur as follows: evaporation, evaporation-pulsation and boiling. The experiment revealed the area having constancy of the heat transfer coefficient at varying specific heat flux that is typical for evaporation. At certain heat flux value the nucleate boiling in the grooves is initiated, and heat transfer coefficient is growing at increasing heat flux. Boiling in the channels of micro-grooved surface is accompanied by a slug boiling regime, and formation of a thin liquid film on the surface of the channel. It is essentially increasing the heat transfer characteristics of the micro-grooved structures. Double of the channel depth leads to increase in heat transfer coefficient up to 30 - 40% for both water and ethanol. Increase of the heat transfer coefficient could be explained by the enlargement of the heat transfer surface of the channels. Increasing of the effective pore radius by the increasing of the channels depth leads to reduction in the hydraulic resistance of the channels that accompanies increase of the critical heat flux up to 50 - 60%.

Groove design for form fit joints made by electromagnetic pulse crimping

The electromagnetic pulse process can be an alternative for many conventional productionprocesses. It can be used for perforating, cutting, welding, forming and crimping. In this thesis, the latter willbe investigated in detail, with the emphasis on tubular joints bearing axial tension and/or torsion loading.To get acquainted with the subject, first a literature study was performed concerning the general principlesof electromagnetic pulse crimping. Because a new field shaper had to be designed, literature on this topicwas also consulted. Finally, the design and use of grooves in crimp joints was studied. It has been reportedthat an inner piece (mandrel) with additional grooves in the joining zone significantly increases the strengthof a crimped joint [1]. However, the information on electromagnetic pulse crimping with a mandrel with morethan one groove is very limited. Therefore one of the main goals of this thesis is to determine an optimaldesign for a mandrel with two grooves used for axially loaded joints. A combination of finite elementsimulations and experiments was used to draw preliminary conclusions involving the double groove design.In a later stage torsional joints will be designed and suitable filler materials to realize leak proof joints will beevaluated.

Stability Enhancement by Casing Grooves: The Importance of Stall Inception Mechanism and Solidity

This paper concerns the optimization of casing grooves and the important influence of stall inception mechanism on groove performance. Installing casing grooves is a well known technique for improving the stable operating range of a compressor, but the wide-spread use of grooves is restricted by the loss of efficiency and flow capacity. In this paper, laboratory tests are used to examine the conditions under which casing treatment can be used to greatest effect. The use of a single casing groove was investigated in a recently published companion paper. The current work extends this to multiple-groove treatments and considers their performance in relation to stall inception mechanisms. Here it is shown that the stall margin gain from multiple grooves is less than the sum of the gains if the grooves were used individually. By contrast, the loss of efficiency is additive as the number of grooves increases. It is then shown that casing grooves give the greatest stall margin improvement when used in a compressor, that exhibits spike-type stall inception, while modal activity before stall can dramatically reduce the effectiveness of the grooves. This finding highlights the importance of being able to predict which stall inception mechanism might occur in a given compressor before and after grooves are added. Some published prediction techniques are therefore examined, but found wanting. Lastly, it is shown that casing grooves can, in some cases, be used to remove rotor blades and produce a more efficient, stable, and light-weight rotor.

Efficient laser-produced plasma extreme ultraviolet sources using grooved Sn targets

An efficient extreme ultraviolet (EUV) generation method has been developed with the use of a CO2 laser-produced plasma from a grooved target. A ∼5% conversion efficiency from laser to 13.5 nm photons was obtained with the use of grooves in a tin target or by repeated laser pulse shots at the same target position. Modeling studies proved that the groove target controls the hydrodynamic expansion of the plasma leading to confinement which prevents the plasma escaping from the EUV production zone.

Comprehensive approach to realizing new technologies for the production of high-precision cold-worked tubes

This article examines aspects of the interaction of parameters of the operation of “cold (warm) Pilger rolling” in the production of tubes of high-alloy steels for power-plant construction. It was established that in addition to the design of the pass system of the tool, one factor that has a significant effect on the distribution of the partial strains along the working cone of tube cold-rolling mills is the strength properties of the metal in the deformation zone. Those properties in turn depend on the temperature to which the semifinished product is heated prior to rolling. To improve the quality of tubes with respect to the accuracy of their geometric dimensions, it is necessary to adopt a new approach to determining the parameters of the surface of the pass grooves on tube cold-rolling mills. This approach includes the use of grooves in which the form of the cross section varies along the working cone. Proportional-reduction design principles are still observed in this case.

Rectification, mixing, self‐induced oscillations, measurement and control in asymmetrically grooved channels

AbstractTwo separate constructions used in advanced microfluidics are combined to achieve controlled mixing and mass transport at maximum efficiency over minimal distance. One is the use of grooves to enhance mixing – an intensively investigated technique employed in electronic components cooling. So far, only grooves of ectangular cross–sections were used. The other construction builds on the well known effect of partial rectification in axially asymmetric channels and has been employed for valvless pumping. It is now shown that a cascade of axially asymmetric grooves retains and even improves the rectification efficiency of a single nozzle while offering the potential of simultaneous mixing enhancement by a factor of more than 2. The latter is achieved in a certain range of moderate Reynolds numbers characterized by self–induced oscillations at much higher frequency than that of flow actuation. Tuning the pressure drop provides precise control of the effective flow rate, up to suppression or reversion. The duration and intensity of mixing and shearing can thus be adjusted within a broad range and effected in very short channels without additional actuators. In the regime of self–induced oscillations, a few identical sensors with sufficient temporal resolution for temperature or concentration allow reliable determination of the flow rate as well as of the admixture composition of the transported fluid. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Design of well and groove microchannel bioreactors for cell culture

Microfluidic bioreactors have been shown valuable for various cellular applications. The use of micro-wells/grooves bioreactors, in which micro-topographical features are used to protect sensitive cells from the detrimental effects of fluidic shear stress, is a promising approach to culture sensitive cells in these perfusion microsystems. However, such devices exhibit substantially different fluid dynamics and mass transport characteristics compared to conventional planar microchannel reactors. In order to properly design and optimize these systems, fluid and mass transport issues playing a key role in microscale bioreactors should be adequately addressed. The present work is a parametric study of micro-groove/micro-well microchannel bioreactors. Operation conditions and design parameters were theoretically examined via a numerical model. The complex flow pattern obtained at grooves of various depths was studied and the shear protection factor compared to planar microchannels was evaluated. 3D flow simulations were preformed in order to examine the shear protection factor in micro-wells, which were found to have similar attributes as the grooves. The oxygen mass transport problem, which is coupled to the fluid mechanics problem, was solved for various groove geometries and for several cell types, assuming a defined shear stress limitation. It is shown that by optimizing the groove depth, the groove bioreactor may be used to effectively maximize the number of cells cultured within it or to minimize the oxygen gradient existing in such devices. Moreover, for sensitive cells having a high oxygen demand (e.g., hepatocytes) or low endurance to shear (e.g., human embryonic stem cells), results show that the use of grooves is an enabling technology, since under the same physical conditions the cells cannot be cultured for long periods of time in a planar microchannel. In addition to the theoretical model findings, the culture of human foreskin fibroblasts in groove (30 microm depth) and well bioreactors (35 microm depth) was experimentally examined at various flow rates of medium perfusion and compared to cell culture in regular flat microchannels. It was shown that the wells and the grooves enable a one order of magnitude increase in the maximum perfusion rate compared to planar microchannels. Altogether, the study demonstrates that the proper design and use of microgroove/well bioreactors may be highly beneficial for cell culture assays.

Theoretical simulation of ripples for different leading-side groove volumes on manifolds in fixed-displacement axial-piston pump

For many hydraulic systems, fixed-displacement axial-piston pumps often employ swash plate. The design challenge for such a pump is to minimize the pressure and flow ripples and the consequent noises. Although the use of grooves at the leading and trailing sides of the pump manifolds has been adopted by several manufacturers as a remedy to this problem, theoretical modelling and analysis of the effects of these silencing grooves are very limited. This study presents a model that puts special emphasis on analysing the effect of volume variation of the silencing grooves. All the non-linear dynamic and algebraic equations developed during modelling have been solved in a Matlab/Simulink framework. The analysis has been carried out for a pump with leading-side manifolds, since experimental results for such a pump were available. Through a constant-speed parametric analysis at fixed load, optimal dimensions for these grooves have been indicated. The major contribution of the present work is the development of a mathematical model that attempts an explicit solution of pressure within each silencing groove. The model has been presented in the analysis as an effective design analysis tool for minimizing the pressure and flow ripples.

Effect of groove-type chip breakers on twist drill performance

This paper proposes the use of grooves placed on the rake face of a twist drill to facilitate chip breaking and reduce drilling forces and chip clogging. A procedure to design grooves including groove geometry and orientation is discussed. Two sets of experiments are presented that determine the effect of grooves on the forces, chip morphology, and critical depth, and compare the life of the grooved and ungrooved drills. The grooves are found to be very effective in breaking chips and preventing chip clogging. Experiments show the positive effects of the grooves including lower drilling torque and thrust, lower chip evacuation forces, lower cutting forces, increased critical depth and increased drill life.