Experimental Investigation of Solid Particle Erosion in Successive Elbows in Gas Dominated Flows

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Alireza Asgharpour ◽  
Peyman Zahedi ◽  
Hadi Arabnejad Khanouki ◽  
Siamack A. Shirazi ◽  
Brenton S. McLaury
Keyword(s):  
Phase Distribution ◽  
Erosive Wear ◽  
High Impact ◽  
Stratified Flows ◽  
Solid Particle Erosion ◽  
Flow Conditions ◽  
In Series ◽  
Paint Removal ◽  
Impact Region

Abstract When a fluid containing erosive particles flows through two or more elbows mounted in series with short distances between them, the downstream elbows which are installed after the first elbow are exposed to erosion from a flow that is not fully developed, and therefore, the characteristics of erosive wear in the second elbow can be different than the first. In this work, the erosion magnitude and pattern in two standard successive vertical–horizontal and horizontal–vertical elbows are examined experimentally. Utilizing an ultrasonic technique (UT), erosion measurements are performed in gas–sand and gas–liquid–sand annular flows to investigate the effects of particle size and flowrates. A paint removal study is also performed to capture the erosion patterns in two elbows for different flow conditions. Using two clear elbows, a flow visualization is performed which shows the quality of phase distribution in the two elbows in series in annular and stratified flows. Measurements show the erosion in the second elbow for this geometry and these flow conditions are less than or in a few cases nearly equal to the first elbow. The location of maximum erosion for all the cases considered is around 45 and 65 deg from the inlet of the elbow in the first and second elbows, respectively. Two areas of high impact frequencies are identified in both elbows. One high-intensity particle impact region which is affected primarily by first impact of particles, and another pattern is formed due to rebounded particles from the first impact.

Experimental Investigation of Solid Particle Erosion in Successive Elbows in Gas Dominated Flows

2018 ◽  
Author(s):  
Alireza Asgharpour ◽  
Peyman Zahedi ◽  
Hadi Arabnejad Khanouki ◽  
Siamack A. Shirazi ◽  
Brenton S. McLaury
Keyword(s):  
Phase Distribution ◽  
State Of The Art ◽  
Flow Direction ◽  
Erosive Wear ◽  
Flow Conditions ◽  
In Series ◽  
Particle Velocities ◽  
Paint Removal ◽  
Impact Region

When a fluid containing erosive particles flows through two or more elbows mounted in series with short distances between them, the downstream elbows which are installed after the first elbow are exposed to erosion from a flow that is not fully developed. Particle velocities and concentration distributions change due to change of flow direction within the first elbow which may cause the characteristics of erosive wear in the second elbow to be different than the first. In the present study, the erosion magnitude and pattern in two 4-inch standard successive elbows installed with 13D distance from each other are examined experimentally. Utilizing a state-of-the-art ultrasonic technique, erosion measurements are performed in gas-sand and gas-liquid-sand annular flows to investigate the effects of particle size and flow rates. A paint removal study is also performed to capture the erosion patterns in two elbows for different flow conditions. Using two clear elbows, a flow visualization is performed which shows the quality of phase distribution in the two elbows in series in annular and stratified flows. Erosion measurements show the results in the second elbow for this geometry and these flow conditions are less than or in a few cases nearly equal to the first elbow. The location of maximum erosion for all the cases considered is around 45 and 65 degrees from the inlet of the elbow in the first and second elbows, respectively. Two areas are identified in erosion patterns of both elbows. One high intensity particle impact region which is affected primarily by first impact of particles, and another pattern is formed due to impacting particles that have rebounded from the first impact.

CFD Predictions and Experiments of Erosion of Elbows in Series in Liquid Dominated Flows

2018 ◽  
Author(s):  
Thiana A. Sedrez ◽  
Yeshwanth R. Rajkumar ◽  
Siamack A. Shirazi ◽  
Hadi Arabnejad Khanouki ◽  
Brenton S. McLaury
Keyword(s):  
Solid Particle Erosion ◽  
Flow Conditions ◽  
Erosion Modeling ◽  
Cfd Simulations ◽  
Horizontal Orientation ◽  
In Series ◽  
Computational Fluid Dynamics Cfd ◽  
Sand Flow ◽  
Pattern Visualization ◽  
Good Agreement

Most previous studies of solid particle erosion in elbows considered an elbow for which the upstream length is long (L/D>100) and flow is well developed before reaching the elbow. But, in this study, experiments were conducted for two elbows in series, one in vertical upward-horizontal orientation and the second one placed after L/D = 6 in horizontal-vertical downward orientation. Erosion experiments were conducted with liquid-sand and liquid-gas-sand flow conditions in an experimental facility with two test section configurations: metallic elbows in series for erosion measurements and acrylic elbows in series for erosion pattern visualization. The experiments include erosion measurements of both metallic elbows with ultrasonic wall thickness (UT) measurements. All experiments including flow visualization of erosion pattern were conducted for both elbows for liquid dominated flows, and the results comparing the erosion ratio of the second elbow to the first elbow are presented. In addition, Computational Fluid Dynamics (CFD) simulations have been performed and compared to the experimental erosion patterns with both erosion pattern visualization and UT measurements. The results show good agreement between experiments and CFD simulations and experimental results provide a database for improving erosion modeling in liquid dominated flows.

Status of nondestructive control of transport function metal products at JSC EVRAZ NTMK

2020 ◽  
Vol 76 (6) ◽  
pp. 586-590
Author(s):  
S. P. Bersenev ◽  
E. M. Slobtsova
Keyword(s):  
Crack Detection ◽  
Middle Part ◽  
Control Line ◽  
Magnetic Powder ◽  
Nondestructive Control ◽  
Automated Control ◽  
Ultrasonic Control ◽  
Acoustic Contact ◽  
In Series

Achievements in the area of automated ultrasonic control of quality of rails, solid-rolled wheels and tyres, wheels magnetic powder crack detection, carried out at JSC EVRAZ NTMK. The 100% nondestructive control is accomplished by automated control in series at two ultrasonic facilities RWI-01 and four facilities УМКК-1 of magnetic powder control, installed into the exit control line in the wheel-tyre shop. Diagram of location, converters displacement and control operations in the process of control at the facility RWI-01 presented, as well as the structural diagram of the facility УМКК-1. The automated ultrasonic control of rough tyres is made in the tyres control line of the wheel-tyre shop at the facility УКБ-1Д. The facility enables to control internal defects of tyres in radial, axis and circular directions of radiation. Possibilities of the facility УКБ-1Д software were shown. Nondestructive control of railway rails is made at two facilities, comprising the automated control line of the rail and structural shop. The УКР-64Э facility of automated ultrasonic rails control is intended to reveal defects in the area of head, web and middle part of rail foot by pulse echo-method with a immersion acoustic contact. The diagram of rail P65 at the facility УКР-64Э control presented. To reveal defects of the macrostructure in the area of rail head and web by mirror-shadow method, an ultrasonic noncontact electromagnetic-acoustic facility is used. It was noted, that implementation of the 100% nondestructive control into the technology of rolled stuff production enabled to increase the quality of products supplied to customers and to increase their competiveness.

Effect of laser rescanning on Ti6Al4V microstructure during selective laser melting

2020 ◽  
pp. 095440542097609
Author(s):  
Weipeng Duan ◽  
Meiping Wu ◽  
Jitai Han
Keyword(s):  
Wear Resistance ◽  
Titanium Alloy ◽  
Selective Laser Melting ◽  
Human Body ◽  
High Impact ◽  
Laser Melting ◽  
Heat Treated ◽  
Volume Porosity ◽  
Biomedical Field

TC4, which is one of the most widely used titanium alloy, is frequently used in biomedical field due to its biocompatible. In this work, selective laser melting (SLM) was used to manufacture TC4 parts and the printed parts were heat-treated using laser rescanning technology. The experimental results showed that laser rescanning had a high impact on the quality of SLMed part, and a different performance on wear resistance can be found on the basis. It can be seen that the volume porosity of the sample was 7.6 ± 0.5% without using any further processing technology. The volume porosity of the sample processed using laser rescanning strategy was decreased and the square-framed rescanning strategy had a relative optimal volume porosity (1.5 ± 0.3%) in all these five samples. With the further decreasing of volume porosity, the wear resistance decreased at the same time. As its excellent bio-tribological properties, the square-framed rescanning may be a potential suitable strategy to forming TC4 which used in human body.

scholarly journals Image Denoising Using Discrete Wavelet Transform : A Theoretical Framework

2018 ◽  
Vol 7 (2.16) ◽  
pp. 120
Author(s):  
Praveen Bhargava ◽  
Shruti Choubey ◽  
Rakesh Kumar Bhujade ◽  
Nilesh Jain
Keyword(s):  
Image Denoising ◽  
Ultra Sound ◽  
Discrete Wavelet ◽  
Transform Domain ◽  
Hybrid Filter ◽  
Edge Sharpness ◽  
In Series ◽  
Salt And Pepper ◽  
Image Type

Noise is a random variation in brightness and color in image or simply we can say that unwanted signals are called noise. The noise is mixed with original signal and cause may troubles. Due to the presence of noise, quality of image is reduced and other features like edge sharpness and pattern recognition are badly affected. In image denoising methods to improve the results a hybrid filter is used for better visualization. The hybrid filter is composed with the combination of three filters connected in series. The hybridization has performed much better in case of salt and pepper type of noise and for most of the medical image type, either MRI, CT, SPECT, Ultra Sound. PSNR values show major improvement in comparison of other existing methods. Future, the results obtained from the presented denoising experiments would be tried to be improved further by using this method with other transform domain methods. Finally, the results are concluded that the proposed approach in terms of PSNR, MSE improvement is outperformed. 

scholarly journals AMPLIFIER DESIGN FOR MODELING THE TRANSMISSION OF A DIGITAL VIDEO SIGNAL OVER A DATA TRANSMISSION CHANNEL

2021 ◽  
Vol 445 (1) ◽  
pp. 39-45
Author(s):  
M. Amreev ◽  
R. Safin ◽  
T. Pavlova ◽  
E. Temyrkanova ◽  
Y. Garmashova
Keyword(s):  
Transmission Line ◽  
Video Surveillance ◽  
Video Transmission ◽  
Main Task ◽  
Surveillance Systems ◽  
Video Signals ◽  
Ohmic Resistance ◽  
In Series ◽  
Amplifier Design

The use of video surveillance systems is used in the areas of security, law and order, in the territories of protected objects, in monitoring the movement of road vehicles and in other areas. The main disadvantage of a video surveillance system is its susceptibility to weather influences (rain, fog, snowfall, etc.), which degrades the quality of the video system by reducing the signal level. Therefore, the urgency of finding new ways and possibilities to improve the quality of video signals is one of the priority areas of signal processing. The main task of this work was to determine the main parameters, simulate the transmission line and amplifier, and select the schematic diagram of the transmitting and receiving path with the voltage and current ratings. Both the receiver and the cable video transmitter have different means of adjusting to different transmission line lengths. The signal at the output of each receiver should be in the range from 0.9 to 1.1 V, and the spread of the total ohmic resistance of the wires of the video transmission line at the input of the receiver should be no more than 2 – 3%. Based on these parameters, the equipment is configured for transmitting video over the channel. The magnitude of the mismatch is regulated by potentiometers, which allow smooth adjustment of the video transmission equipment [1]. As a rule, video transmission over the channel is carried out at a distance of 50 to 1500 m. If it is necessary to transmit video at distances less than 50 m, additional resistances are connected in series at the receiver input so that the total line resistance is 30 - 50 Ohm [1].

scholarly journals A cross-sectional study of the reporting quality of pilot or feasibility trials in high-impact anesthesia journals

2018 ◽  
Vol 65 (11) ◽  
pp. 1180-1195 ◽  
Author(s):  
Harsha Shanthanna ◽  
Alka Kaushal ◽  
Lawrence Mbuagbaw ◽  
Rachel Couban ◽  
Jason Busse ◽  
...  
Keyword(s):  
Reporting Quality ◽  
Cross Sectional Study ◽  
High Impact ◽  
Sectional Study ◽  
Cross Sectional

Obstructive sleep apnea is common in patients with high-impact chronic pain – an exploratory study from an interdisciplinary pain center

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dennis Boye Larsen ◽  
Laila Bendix ◽  
Karin Abeler ◽  
Kristian Kjær Petersen ◽  
Michael Sprehn ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Clinical Utility ◽  
Pain Treatment ◽  
Objective Assessment ◽  
High Impact ◽  
Sleep Monitoring ◽  
Predictive Values ◽  
Clinical Pain ◽  
Obstructive Sleep

Abstract Objectives Sleep disturbances are increasingly recognized as a major part of chronic pain pathology. Obstructive sleep apnea (OSA) is a common occurrence in patients with chronic pain attending specialized pain clinics, yet its prevalence remains unclear. Using screening tools such as the Berlin and STOP-BANG questionnaires may aid in early identification of OSA and improve clinical care. This study i) examined the frequency of OSA based on objective sleep monitoring in patients with high-impact chronic pain, ii) explored potential differences in self-reported pain and sleep characteristics between patients with and without OSA, and iii) tested the agreement between OSA classification based on objective assessment and two OSA screening questionnaires. Methods A consecutive cohort of 90 patients (71 women and 19 men; mean age: 47.1 ± 11.0 years) referred for interdisciplinary pain treatment, underwent one night of sleep monitoring using portable respiratory polygraphy (RP), and suspected OSA was confirmed with polysomnography (PSG). Self-reported data on clinical pain (severity, pain drawings and health-related quality of life), sleep characteristics (sleep quality insomnia, sleepiness), and risk of OSA (Berlin and STOP-BANG questionnaires) were collected the day before RP assessment. Results Forty-six (51.1%) patients were classified with OSA according to RP and verified with PSG. Twenty-eight patients (31.1%) had moderate or severe OSA (apnea-hypopnea index [AHI] >15). Patients with OSA reported lower sleep quality compared with patients without OSA. Scores on pain severity, disability, quality of life, insomnia and sleepiness were comparable between patients with and without OSA. Sensitivity and specificity were 78.6 and 45.2% respectively for the Berlin questionnaire, and 71.4 and 58.1% respectively for the STOP-BANG questionnaire. The agreement for both questionnaires with objective assessment was poor-to-fair. Both questionnaires had acceptable negative predictive values but low positive predictive values reducing the clinical utility to identify patients with low OSA-risk in this sample. Conclusions The current study demonstrates a high prevalence of OSA in patients with high-impact chronic pain referred to specialized pain treatment, however the clinical pain profiles were similar in patients with and without OSA. The Berlin and STOP-BANG questionnaires have poor specificity and low-to-fair agreement with RP/PSG questioning their clinical utility in identifying OSA in this sample.

Enhancing the Quality of High‐Impact Practices Through Taxonomies

2019 ◽  
Vol 31 (2) ◽  
pp. 8-14 ◽  
Author(s):  
Jennifer Thorington Springer ◽  
Julie Hatcher ◽  
Matthew Rust ◽  
Amy A. Powell
Keyword(s):  
High Impact ◽  
High Impact Practices

scholarly journals Pathogenesis and prevention strategies for equine tendinopathy

2019 ◽  
Vol 37 (3) ◽  
pp. 18-19
Author(s):  
Roger K.W. Smith
Keyword(s):  
Risk Factors ◽  
High Risk ◽  
Flexor Tendon ◽  
High Impact ◽  
Prevention Strategies ◽  
Suspensory Ligament ◽  
High Risk Factors ◽  
Superficial Digital Flexor Tendon ◽  
External Trauma

Equine tendinopathy arises through two main mechanisms – external trauma or overstrain injury. The pathogenesis of the former is straight forward and prevention relies on avoiding risk factors for palmar/plantar lacerations and protecting the tendons through the use of boots. For over-strain injuries, these mostly arise from overloading of the distal limb resulting in mid-substance tearing of the digital flexor tendons or borders tears of the deep digital flexor tendon within the confines of the digital sheath and navicular bursa. While some of these injuries may be spontaneous injuries associated solely with overload (such as the intra-thecal injuries of the deep digital flexor tendon), it is widely accepted that most overstrain injuries of the superficial digital flexor tendon (and suspensory ligament) occur as a result of accumulated microdamage which predisposes the tendon to over-strain injury. The mechanisms of this accumulated microdamage are poorly understood but probably relate to the effect of high impact loading of the tendon, sustained during normal exercise, which drives degradative changes in the tendon fascicles (Dudhia et al. 2007) and, in particular, the interfascicular matrix (endotenon) that allows the fascicles to slide past one another as a mechanism for the spring-like extension of the tendon under load (Thorpe et al. 2013). This is compounded by the lack of adaptive remodelling in adult tendon (Smith et al. 2002). This subclinical damage makes the tendon prone to sudden tearing of the tendon matrix during normal exercise, the risk of which is increased by factors such as the firmness of the ground, weight, speed, and fatigue. Strategies for prevention of injury rely on identifying at risk individuals through more sensitive monitoring of tendon health, maximising the quality of tendon during growth using carefully tailored ‘conditioning’ exercise regimes (Smith & Goodship 2008), reducing the degeneration induced by normal training and competition, and avoiding high risk factors for the initiation of the clinical injury.

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