Characterisation of Metal Debris in Grinding and Flotation Circuits

AbstractDue to the risk of adverse reactions to metal debris resulting from increased wear of the arthroplasty more than one million metal-on-metal (MoM) hip replacements worldwide are in active follow-up. Follow-up usually includes measurement of both whole blood cobalt (Co) and chromium (Cr) concentrations. Our experience is that Cr is seldom independently elevated. We wanted to ascertain whether blood Cr measurements could be omitted from follow-up protocols without lowering the quality of follow-up. We identified 8438 whole blood Co and Cr measurements performed without or prior to revision surgery. When the cut-off levels 5 µg/L and 7 µg/L were used, Cr was independently elevated in only 0.5% (95% confidence interval, CI, 0.3 to 0.6) and 0.2% (CI 0.1 to 0.3) of the measurements. The models with continuous variables showed that the higher the blood metal concentrations are the lower the percentage of measurements with Cr higher than Co. Our results suggest that whole blood Cr is very rarely independently elevated and therefore the authorities should consider omitting Cr measurements from their screening guidelines of MoM hip replacements. We believe this change in practice would simplify follow-up and lead to cost savings without decreasing the quality of follow-up.

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Small-head metal on metal total hip arthroplasty is associated with a high rate of complication and reoperation at mid-term follow-up

SAGE Open Medicine ◽

10.1177/20503121211014707 ◽

2021 ◽

Vol 9 ◽

pp. 205031212110147

Author(s):

Nobuhiko Sumiyoshi ◽

Kazuhiro Oinuma ◽

Yoko Miura

Keyword(s):

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Adverse Reactions ◽

Small Diameter ◽

High Rate ◽

Metal Debris ◽

Total Hip ◽

Metal On Metal ◽

Small Head

Background: Adverse reactions to metal debris are significant complications after metal-on-metal total hip arthroplasty. Recently, late appearances of adverse reactions to metal debris and subsequent need for reoperations have been reported with small-diameter head metal-on-metal devices. We retrospectively investigated mid-term clinical outcomes of small-head metal-on-metal total hip arthroplasty. Methods: We reviewed 159 hips in 139 patients who had a small-head metal-on-metal total hip arthroplasty (M2a Taper; Biomet, Warsaw, IN) with a minimum 5-year follow-up and documented postoperative complications. Results: Focal osteolysis in either the femur or acetabulum was observed in 12 hips (7.5%, 44 months after surgery on average), with pseudotumor observed in 8 hips (5%, 120 months after surgery on average). Four hips (2.5%) had dislocations (84 months after surgery on average) and six hips (3.8%, 122 months after surgery on average) underwent reoperation. Conclusion: Small-head metal-on-metal total hip arthroplasty is associated with a high degree of complications at mid-term follow-up period. Considering this, we discourage the use of metal-on-metal total hip arthroplasty regardless of head size.

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Unsupervised Foreign Object Detection Based on Dual-Energy Absorptiometry in the Food Industry

Journal of Imaging ◽

10.3390/jimaging7070104 ◽

2021 ◽

Vol 7 (7) ◽

pp. 104

Author(s):

Vladyslav Andriiashen ◽

Robert van Liere ◽

Tristan van Leeuwen ◽

Kees Joost Batenburg

Keyword(s):

Object Detection ◽

Meat Products ◽

Food Product ◽

Processing Technique ◽

Dual Energy ◽

Foreign Object ◽

Metal Debris ◽

X Ray ◽

Foreign Objects ◽

X Ray Imaging

X-ray imaging is a widely used technique for non-destructive inspection of agricultural food products. One application of X-ray imaging is the autonomous, in-line detection of foreign objects in food samples. Examples of such inclusions are bone fragments in meat products, plastic and metal debris in fish, and fruit infestations. This article presents a processing methodology for unsupervised foreign object detection based on dual-energy X-ray absorptiometry (DEXA). A novel thickness correction model is introduced as a pre-processing technique for DEXA data. The aim of the model is to homogenize regions in the image that belong to the food product and to enhance contrast where the foreign object is present. In this way, the segmentation of the foreign object is more robust to noise and lack of contrast. The proposed methodology was applied to a dataset of 488 samples of meat products acquired from a conveyor belt. Approximately 60% of the samples contain foreign objects of different types and sizes, while the rest of the samples are void of foreign objects. The results show that samples without foreign objects are correctly identified in 97% of cases and that the overall accuracy of foreign object detection reaches 95%.

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A Novel Impedance Micro-Sensor for Metal Debris Monitoring of Hydraulic Oil

Micromachines ◽

10.3390/mi12020150 ◽

2021 ◽

Vol 12 (2) ◽

pp. 150

Author(s):

Hongpeng Zhang ◽

Haotian Shi ◽

Wei Li ◽

Laihao Ma ◽

Xupeng Zhao ◽

...

Keyword(s):

Magnetic Field ◽

Wear Debris ◽

Detection Method ◽

Silicon Steel ◽

Detection Sensitivity ◽

Normal Operation ◽

Metal Debris ◽

Hydraulic Oil ◽

Steel Strips ◽

The Magnetic Field

Hydraulic oil is the key medium for the normal operation of hydraulic machinery, which carries various wear debris. The information reflected by the wear debris can be used to predict the early failure of equipment and achieve predictive maintenance. In order to realize the real-time condition monitoring of hydraulic oil, an impedance debris sensor that can detect inductance and resistance parameters is designed and studied in this paper. The material and size of wear debris can be discriminated based on inductance-resistance detection method. Silicon steel strips and two rectangular channels are designed in the sensor. The silicon steel strips are used to enhance the magnetic field strength, and the double rectangular detection channels can make full use of the magnetic field distribution region, thereby improving the detection sensitivity and throughput of the sensor. The comparison experiment shows that the coils in series are more suitable for the monitoring of wear debris. By comparing and analyzing the direction and the presence or absence of the signal pulses, the debris sensor can detect and distinguish 46 µm iron particles and 110 µm copper particles. This impedance detection method provides a new technical support for the high-precision distinguishing measurement of metal debris. The sensor can not only be used for oil detection in the laboratory, but also can be made into portable oil detection device for machinery health monitoring.

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Reliability of Total Nucleated Cell Counts in the Setting of Hip Arthroplasty

The Journal of Applied Laboratory Medicine ◽

10.1093/jalm/jfaa183 ◽

2020 ◽

Author(s):

Lauren N Pearson ◽

Robert L Schmidt ◽

Kenneth Cahoon ◽

Christopher E Pelt

Keyword(s):

Synovial Fluid ◽

Total Hip Arthroplasty ◽

Hip Arthroplasty ◽

Metal Debris ◽

Total Hip ◽

Cell Counts ◽

History Of ◽

Joint Effusions ◽

Automated Instruments ◽

Automated Methods

Abstract Background Total nucleated cell (TNC) count and differential are used to classify joint effusions as inflammatory or noninflammatory. Further diagnostic evaluation and management is contingent on this classification. TNC count can be measured by automated analyzers or by manual assessment using a hemocytometer. Studies have raised concerns regarding the accuracy of TNC counts measured by automated instruments, particularly in the setting of joint arthroplasty. The objective of this study was to determine whether metallosis, a complication of total hip arthroplasty in which metal debris accumulates in periprosthetic tissues and synovial fluid, is associated with inaccurate TNC counts in synovial fluid. Methods We compared the accuracy of cell counts measured by the Sysmex XN-1000 and Beckman Coulter Iris iQ200 with the gold standard of manual assessment using a hemocytometer in synovial fluid from patients with suspected metallosis and in fluid obtained from controls from patients with native joints and a history of arthroplasty for other indications. Results TNC counts produced by automated analyzers were associated with increased levels of discordance (relative to manual counts) in patients with metallosis. Metallosis was not associated with increased levels of discordance for RBC counts or WBC differentials. The Sysmex XN flagged all but 1 metallosis sample for manual verification of the results. Conclusions Automated methods are generally reliable for analysis of synovial fluid. TNC counts can be inaccurate in the context of metallosis following total hip arthroplasty. Laboratories should correlate automated cell counts with a microscopic assessment of the specimen, as recommended by instrument manufacturers.

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Wear Assessment in a Biodiesel Fueled Compression Ignition Engine

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1501079 ◽

2003 ◽

Vol 125 (3) ◽

pp. 820-826 ◽

Cited By ~ 78

Author(s):

A. K. Agarwal ◽

J. Bijwe ◽

L. M. Das

Keyword(s):

Coefficient Of Friction ◽

Linseed Oil ◽

Diesel Oil ◽

Lubricating Oil ◽

Engine Fuel ◽

Compression Ignition ◽

Compression Ignition Engine ◽

Metal Debris ◽

Wear Rates ◽

Biodiesel Blend

Biodiesel is prepared using linseed oil and methanol by the process of transesterification. Use of linseed oil methyl ester (LOME) in a compression ignition engine was found to develop a highly compatible engine-fuel system with low emission characteristics. Two similar engines were operated using optimum biodiesel blend and mineral diesel oil, respectively. These were subjected to long-term endurance tests. Lubricating oil samples drawn from both engines after a fixed interval were subjected to elemental analysis. Quantification of various metal debris concentrations was done by atomic absorption spectroscopy (AAS). Wear metals were found to be about 30% lower for a biodiesel-operated engine system. Lubricating oil samples were also subjected to ferrography indicating lower wear debris concentrations for a biodiesel-operated engine. The additional lubricating property of LOME present in the fuel resulted in lower wear and improved life of moving components in a biodiesel-fuelled engine. However, this needed experimental verification and quantification. A series of experiments were thus conducted to compare the lubricity of various concentrations of LOME in biodiesel blends. Long duration tests were conducted using reciprocating motion in an SRV optimol wear tester to evaluate the coefficient of friction, specific wear rates, etc. The extent of damage, coefficient of friction, and specific wear rates decreased with increase in the percentage of LOME in the biodiesel blend. Scanning electron microscopy was conducted on the surfaces exposed to wear. The disk and pin using 20% biodiesel blend as the lubricating oil showed lesser damage compared to the one subjected to diesel oil as the lubricating fluid, confirming additional lubricity of biodiesel.

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