Reliability of new radiographic measurement techniques for elbow bony impingement

Background Identifying the location and scale of radiographic changes in elbow bony impingement (EBI) is critical in formulating an appropriate diagnosis and treatment plan for such patients. The purpose of present study was to evaluate the intra-rater and inter-rater reliability of the new radiographic parameters, Anterior Impingement angle (AIa) and Posterior Impingement angle (PIa), for EBI. In addition, to determine if there was a relationship between radiographic parameters and clinical evaluation. Patients and methods Three raters of different levels of training evaluated the radiographs of 60 patients (30 in EBI group and 30 in normal group) twice, at least 2 weeks apart. Intra-rater and inter-rater reliabilities were calculated by Intraclass Correlation Coefficients (ICC) with 95% confidence intervals. Correlation between radiographic parameters and clinical evaluation was calculated by Pearson correlation coefficient. Results In both groups, intra-rater and inter-rater reliabilities were substantial. There were no significant differences in reliability between upper-hand expert surgeons and resident for either measurement. Good correlation was observed between impingement arcs and range of motion values. Conclusions Both AIa and PIa measurements demonstrated substantial intra-rater and inter-rater reliability for normal radiographs and in EBI patients. Good reliability, for either expert surgeons or residents in training, and good correlation between radiographic measurements and manual testing, appoints this method may be easily and reliably used in every day practice.

Effect of erosive parameters on solid particle erosion of cotton fiber–based nonwoven mat/wooden dust reinforced hybrid polymer composites

Abrasive particle-induced erosive wear of polymeric engineering components is a major industrial issue. The research of solid particle erosion characteristics of polymeric composites becomes essential due to operational needs in dusty conditions. Nonwovens are now employed in industrial applications for polymeric composites. Nonwoven products are made from a wide range of raw materials, ranging from synthetic to natural fibers. This work finding the effect of nonwoven cotton fiber (5, 10, and 15 wt.%) loading on the physical, mechanical, and erosion wear of fixed wooden dust (4 wt.%) filled hybrid epoxy composites. Experimental results reveal improved impact strength, hardness, and compressive and tensile strength with an increment of fiber loading from 5–15 wt.%. The density of the composites was found to increase, whereas void content decreases with an increase in cotton fiber. The erosion wear of the composites has been studied using an L27 orthogonal array to assess the effects of various parameters such as fiber loading, erodent size, impact velocity, impingement angle, and stand-off distance. The erosion wear increased with impact velocity and remained highest for 60° of impingement angle. The most significant parameter affecting the erosion wear was determined as impact velocity followed by impingement angle. Surface morphologies of eroded samples reveal the fiber pull-out, and fiber breakage was the prominent phenomenon for the erosion wear of the evaluated composites.

Water-droplet erosion behavior of high-velocity oxygen-fuel-sprayed coatings for steam turbine blades

The water-droplet erosion of low-pressure steam turbine blades under wet steam environments can alter the vibration characteristics of the blade, and lead to its premature failure. Using high-velocity oxygen-fuel (HVOF) sprayed water-droplet erosion resistant coating is beneficial in preventing the erosion failure, while the erosion behavior of such coatings is still not revealed so far. Here, we examined the water-droplet erosion resistance of Cr3C2–25NiCr and WC–10Co–4Cr HVOF sprayed coatings using a pulsed water jet device with different impingement angles. Combined with microscopic characterization, indentation, and adhesion tests, we found that: (1) both of the coatings exhibited a similar three-stage erosion behavior, from the formation of discrete erosion surface cavities and continuous grooves to the broadening and deepening of the groove, (2) the erosion rate accelerates with the increasing impingement angle of the water jet; besides, the impingement angle had a nonlinear effect on the cumulative mass loss, and 30° sample exhibited the smallest mass loss per unit area (3) an improvement in the interfacial adhesion strength, fracture toughness, and hardness of the coating enhanced the water-droplet erosion resistance. These results provide guidance pertaining to the engineering application of water erosion protective coatings on steam turbine blades.

Parametric Analysis of Epoxy/Crumb Rubber Composite by Using Taguchi—GRA Hybrid Technique

Effect of parameters affecting solid particle erosion of crumb rubber epoxy composite is investigated. Five important process parameters—impact velocity, impingement angle, standoff distance, erodent size, and crumb rubber content—are taken into consideration. Erosion rate and erosion efficiency are included as the chief objectives. The Taguchi coupled gray relational analysis type statistical model is implemented to study interaction, parameters' effect on responses, and optimized parameters. ANOVA and regression model affirmed impingement angle and crumb rubber content play a significant role to minimize the erosion. Validity of the proposed model is justified with the standard probability plot and R2 value. A confirmation experiment conducted with A2B2C3D3E3 condition registers noticeable enhancement in GRG to the tune of 0.0893.

Computational Analysis of Water-Submerged Jet Erosion

Erosion causes substantial damage in many industrial equipment such as pump components, valves, elbows, and plugged tees. In most cases, erosion is coupled with corrosion, resulting in major financial loss (nearly 3.4% of the global gross domestic product) as evidenced in oil and gas industries. In most cases, the erosion occurs in a submerged water medium. In this paper, erosion characteristics of stainless steel 316 were investigated computationally in a water-submerged jet impingement setup. The erosion profiles and patterns were obtained for various parameters over ranges of inlet velocities (3 to 16 m/s), nozzle diameters (5 to 10 mm), nozzle–target distances (5 to 20 mm), nozzle shapes (circular, elliptical, square, and rectangular), impingement angles (60° to 90°), and particle sizes (50 to 300 µm). The range of Reynolds number studied based on nozzle diameters is 21,000–120,000. The Eulerian–Lagrangian approach was used for flow field prediction and particle tracking considering one-way coupling for the particle–fluid interaction. The Finnie erosion model was implemented in ANSYS-Fluent 19.2 and used for erosion prediction. The computational model was validated against experimental data and the distributions of the erosion depth as well as the locations of the of maximum and minimum erosion points are well matched. As expected, the results indicate an increase in loss of material thickness with increasing jet velocity. Increasing the nozzle diameter caused a reduction in the maximum depth of eroded material due to decreasing the particle impact density. At a fixed fluid inlet velocity, the maximum thickness loss increases as the separation distance between the nozzle outlet and target increases, aspect ratio of nozzle shape decreases, and impingement angle increases. The erosion patterns showed that the region of substantial thickness loss increases as nozzle size/stand-off height increases and as particle size decreases. In addition, increasing the aspect ratio and impingement angle creates skewed erosion patterns.

Erosion wear behaviour of A357/fly ash composites

In this article, a new metal–matrix composite was developed with fly ash (an industrial waste from petroleum industries) as reinforcement and aluminium metal (A357) as a matrix by squeeze casting technique. This study was concentrated on the processing of the composites with different weight percentage ranging from 0 to 10 wt.% in a step of 2.5 each and also reported the erosion wear behaviour. Solid particle erosion of A357/fly ash composites was carried out with four velocities (48, 70, 82 and 109 m/s), at impact angles (30°, 45°, 60° and 90°), with silica as an abrasive particle at ambient temperature. The eroded surfaces were analysed by scanning electron microscopy. The results revealed that the impact velocity and impingement angle both affected the erosion wear behaviour of the composites. The erosion rate rises with an increase in impact velocity, irrespective of the change in impingement angle and weight percentage of the fly ash. The erosion mechanism studied for the composites is microploughing and microcutting.

Nonconventional Machining and Materials Processing: Proposed Design for Abrasive Jet Machining (AJM)

High degree Abrasive Jet (AJ) is applied in Abrasive Jet Machining (AJM) as a process that is based of Machine-driven Energy (MDE). The abrasives are applied in the removal of resources from work surfaces based on impact erosion. AJ is generated through the acceleration of very fine abrasive particles in considerably gas that has been pressurizes i.e. carrier gas. In this case, jets are utilized to transform this pressurized energy into kinetic energy, which is also directs jets to the work surfaces at an impingement angle. During the impact, rigid abrasive particles are used to slowly remove resources through erosion and with the assistance of brittle fracture. This paper evaluates and recommends a design for AJM. The various components have also been chosen after the relevant design assessment procedures have been done. The AJM model has been design with reference to the present components.