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Background: There are concerns regarding glenoid erosion with metal shoulder hemiarthroplasty. PyroCarbon may offer an alternative because of favorable wear characteristics and preservation of the glenoid. The purpose of this study was to assess in vitro bone wear characteristics of PyroCarbon relative to cobalt chromium alloy hemiarthroplasty in a shoulder wear simulator. Methods: Wear of PyroCarbon and cobalt chromium prostheses articulating with bone were characterized by means of bone wear penetration rate, changes to surface roughness, and wear particle analysis. Results: PyroCarbon prostheses produced significantly less damage to bone and were less damaged by the bone than cobalt chromium prostheses. Cobalt chromium testing was halted at approximately 320,000 cycles because the bone was consumed. Wear testing of PyroCarbon specimens continued through five million cycles. Linearized bone penetration rate, bone volume loss rate, and surface roughness for cobalt chromium test specimens were 30 times greater than for PyroCarbon. Conclusions: Results demonstrate significantly less damage to bone in simulated shoulder function testing for PyroCarbon hemiarthroplasty implants relative to conventional cobalt chromium implants. Our study supports use of PyroCarbon in humeral head hemiarthroplasty as a viable alternative to conventional metal hemiarthroplasty. Further investigation of PyroCarbon performance in clinical settings is warranted. [ABSTRACT FROM AUTHOR]

Modeling the space weather conditions for a near‐Earth environment depends on a proper representation of magnetic fields on the Sun. There are discussions in the community with respect to the value of observations taken at several Lagrangian points (L1–L5) in the Sun‐Earth system. Observations from a single (e.g., Earth/L1) vantage point are insufficient to characterize rapid changes in magnetic field on the far side of the Sun. Nor can they represent well the magnetic fields near the solar poles. However, if the changes in sunspot activity were moderate, how well would our predictions of the solar wind based on a single viewing point work? How much improvement could we see by adding magnetograph observations from L5, L4, and even L3? Here, we present the results of our recent modeling, which shows the level of improvement in forecasting the properties of the solar wind at Earth made possible by using additional observations from different vantage points during a period of moderate evolution of sunspot activity. As an example, we also show the improvements to the solar wind forecast from adding a single observation of the southern polar area from out‐of‐ecliptic spacecraft at −30° heliographic latitude vantage point. Key Points: Role of observations from different Lagrange points for solar wind prediction has been investigatedArtificial data and model‐to‐model comparison are usedFor prediction of solar wind at L1/Earth, observations from L5 yield larger improvement as compared with L4 [ABSTRACT FROM AUTHOR]

Abstract Fatigue, oxide and spherical particles are the three most common kinds of wear particles in rotate vector (RV) reducer and are often bonded together in ferrography images. However, conventional methods of wear debris identification cannot classify wear particles when the wear particles stick together. To this end, this study presents a novel model of wear debris classification to cope with this problem. Firstly, the Inception-v3 model is utilised to extract the features of wear particles automatically. Then, a new neural network with three classifiers is devised to simultaneously determine whether there are fatigue particles, oxide particles and spherical particles in the ferrography image. Finally, a large number of particle samples obtained from experiments are used to test the proposed method. The results demonstrate that the proposed model can simultaneously recognise the different types wear particles even the wear particles are overlapped. Moreover, separation of wear particles and selection of features are not required in the proposed method, which provides an objective and convenient approach for the recognition of wear particles. Highlights • A method of wear particle recognition considering particle overlapping is proposed. • Different kinds of wear particles in a sample can be identified simultaneously. • Segmentation of wear particles and selection of features are not required. [ABSTRACT FROM AUTHOR]

Abstract Detecting the presence of circulating tumor cells (CTCs) in peripheral blood can be useful for monitoring treatment in patients, metastasis prognosis, and even early detection. The epidermal growth factor receptor (EGFR) is overexpressed in carcinoma, e.g. in colorectal cancer. Here, we use atomic force microscopy (AFM) force spectroscopy to study the mechanical properties of A431 cells, which simulate EGFR-overexpressing epithelial CTCs and were magnetically isolated by Bio-Ferrography (BF). BF is found useful in isolating individual cancerous cells for mechanical testing, thus avoiding cell-cell interactions. Different stages in the pre-isolation sample preparation steps (namely, cell fixation, PLL coating of the glass substrate, and immunomagnetic labeling) are found to affect the estimated Young's modulus. The BF magnetic isolation step itself does not change the elasticity of the captured cells in comparison to the pre-isolated microbeads-bound cells. The reported increase in the estimated Young's modulus between BF-isolated target cells and fixed cells that are not bound to magnetic microbeads can be used as a quantitative mechanical indicator for objective detection of CTCs. Furthermore, we report a 2.8-fold increase in the adhesion force between the AFM tip and the BF-isolated cells compared to the pre-isolated magnetic microbead-bound A431 fixed cells. This adhesion force correlation could potentially serve as an additional quantitative mechanical indicator for distinguishing between the target and background cells, without the use of cell staining assay and subjective analysis by an expert pathologist. This study demonstrates the powerful combination of the highly sensitive cell isolation by BF and the subsequent analysis of mechanical properties of individual captured cancerous cells by AFM. This combination has potential use in cancer research. [ABSTRACT FROM AUTHOR]

Highlights • The corrected Multi-illumination 2D images are collected through a designed image acquisition system. • An adaptive segmentation method is proposed to effectively extract wear particles from ferrograph images. • Wear particle surfaces are reconstructed by a photometric-stereo based model. Abstract Ferrography has emerged as a significant candidate for the provision of relevant information for the determination of the status of machine wear. However, this conventional methodology provides only marginal results due to its inability to provide 3-dimensinal (3D) surface information. The authors of this paper have developed a methodology based on photometric-stereo towards the enhancement of the capabilities of ferrography. This enhanced and innovative methodology consists of three main components, the multi-illumination image acquisition, the wear particle extraction, and the 3D surface reconstruction. The methodology ensures the reliable and efficient extraction of the wear particles surface topographies for further feature-based wear particle identification. The performance of this methodology has been compared with results observed from the laser scanning confocal microscopy. The outcome of this comparison has depicted that the methodology involving this new low-cost ferrography system exhibits very high accuracy for the 3D surface feature extraction of wear particles. [ABSTRACT FROM AUTHOR]

Magnetic elements have an intensity contrast that depends on the type of region they are located in (for example quiet Sun, or active region plage). Observed values also depend on the spatial resolution of the data. Here we investigate the contrast-magnetic field dependence in active region plage observed near disk center with SUNRISE during its second flight in 2013. The wavelengths under study range from the visible at 525 nm to the near ultraviolet (NUV) at 300 nm and 397 nm. We use quasi-simultaneous spectropolarimetric and photometric data from the Imaging Magnetograph eXperiment (IMaX) and the Sunrise Filter Imager (SuFI), respectively. We find that in all wavelength bands, the contrast exhibits a qualitatively similar dependence on the line-of-sight magnetic field, BLOS, as found in the quiet Sun, with the exception of the continuum at 525 nm. There, the contrast of plage magnetic elements peaks for intermediate values of BLOS and decreases at higher field strengths. By comparison, the contrast of magnetic elements in the quiet Sun saturates at its maximum value at large BLOS. We find that the explanation of the turnover in contrast in terms of the effect of finite spatial resolution of the data is incorrect with the evidence provided by the high-spatial resolution SUNRISE data, as the plage magnetic elements are larger than the quiet Sun magnetic elements and are well-resolved. The turnover comes from the fact that the core pixels of these larger magnetic elements are darker than the quiet Sun. We find that plages reach lower contrast than the quiet Sun at disk center at wavelength bands formed deep in the photosphere, such as the visible continuum and the 300 nm band. This difference decreases with formation height and disappears in the Ca II H core, in agreement with empirical models of magnetic element atmospheres. [ABSTRACT FROM AUTHOR]

Six large magnitude earthquakes in Central Asia which occurred at the end of the 19th century were recorded on early magnetographs in Great Britain. Scalar seismic moment estimates of the 1911 Chon-Kemin, the 1902 Atushi and the 1907 Karatag earthquakes in Central Asia were recently determined by historical seismogram modelling. For those events, we find agreement between moment magnitudes estimated from seismograms and from magnetograms. This supports the assumption of linear scaling of magnetogram amplitudes as function of M 0, which we then use to estimate the moment magnitudes for earlier large-magnitude events, that is, the 1885 Belovodskoe, 1887 Verny and 1889 Chilik earthquakes. The magnetometer data imply that the Chilik earthquake had M W7.9, slightly smaller than the Chon-Kemin event with M W8.0. The Verny earthquake, however, for which we estimate M W7.7, is likely larger than listed in catalogues (M 7.3). Similarly, we find a larger magnitude M W7.6 (instead of the previous M 6.9) for the Belovodskoe earthquake, but this remains uncertain due to measurement imprecision. [ABSTRACT FROM AUTHOR]

Context.Early magnetographic observations indicated that the magnetic field in the solar photosphere has an unresolved small-scale structure. Near-infrared and optical data with extremely high spatial resolution show that these structures have scales of a few tens of kilometres, which are not resolved in the majority of solar observations. Aims.The goal of this study is to establish the effect of the unresolved photospheric magnetic field structure on Stokes profiles observed with relatively low spatial resolution. Ultimately, we aim to develop methods for fast estimation of the photospheric magnetic filling factor and line-of-sight gradient of the photospheric magnetic field, which can be applied to large observational data sets. Methods.We exploit 3D magnetohydrodynamic models of magneto-convection developed using the MURAM code. Corresponding profiles of Fe I 6301.5 and 6302.5 Å spectral lines are calculated using the NICOLE radiative transfer code. The resulting I and V Stokes [x, y, λ] cubes with a reduced spatial resolution of 150 km are used to calculate magnetic field values as they would be obtained in observations with the Solar Optical Telescope (SOT) onboard Hinode or the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamic Observatory (SDO) mission. Results. Three different methods of magnetic filling factor estimation are considered: the magnetic line ratio method, the Stokes V width method, and a simple statistical method. We find that the statistical method and the Stokes V width method are sufficiently reliable for fast filling factor estimations. Furthermore, we find that the Stokes I ± V bisector splitting gradient can be used for fast estimation of the line-of-sight gradient of the photospheric magnetic field. [ABSTRACT FROM AUTHOR]

For about 15 years, studies of fast gas-dynamic processes have been conducted at the Logunov Institute of Experimental Physics (VNIIEF) of the Russian Federal Nuclear Center using the proton radiography system developed jointly with the Logunov Institute of High Energy Physics on the basis of a U-70 accelerator. The main advantages of flash proton radiography over widely used flash x-ray radiography are high spatial resolution, multiframe mode, transmission capability, dynamic range of recording, etc. In recent years, effort has continued to extend the capabilities of the proton radiography system by increasing the total time and recording field and supplementing it with additional diagnostic techniques and new explosion-proof chambers. This paper presents the results of studies that illustrate these capabilities. [ABSTRACT FROM AUTHOR]

Abstract: This paper explores the feasibility of applying genetic programming (GP) to classify wear particles. A marking threshold filter is proposed to preprocess ferrographic images before optimising the feature space of wear particles using GP. Subsequently, evolved features by GP are quantitatively evaluated by the Fisher criterion and distance fitness function, and clustering performance is evaluated qualitatively. The evolved features are compared with a conventional feature set as the inputs to support vector machines, probabilistic neural networks, and k‐nearest neighbour. Results demonstrated that the evolved features indicated a significant improvement in classification accuracy and robustness compared with conventional features. Finally, 3 typical wear particles, sliding, cutting, and oxidative, are successfully classified. [ABSTRACT FROM AUTHOR]

Full-disk spectroheliograms have been taken in Coimbra on a daily basis since 1926 in the Ca II K-line (K1 and K3). Later, in 1989, with the upgrade of the equipment it was possible to start the observations in the H-alpha line. The spectroheliograms of Coimbra constitutes a huge dataset of solar images, which requires an efficient automatic tool to detect and analyze solar activity features. This work presents a mathematical morphology approach applied to the CaII K3 series. The objective is to create a tool based on the segmentation by watershed transform combined with other morphological operators to detect automatically and analyze chromospheric plages during the solar cycle 24. The tool is validated by comparing its results for cycle 23 with those presented by Dorotovic et al. (2007, 2010). The results obtained are in very good agreement with those, including on images obtained in non-ideal meteorological conditions (eg. some clouds in sky). The results were also qualitatively compared with the results obtained through the application of ASSA model to SDO HMI magnetograms. [ABSTRACT FROM AUTHOR]

Context. The Helioseismic and Magnetic Imager (HMI) provides continuum images and magnetograms with a cadence better than one per minute. It has been continuously observing the Sun 24 h a day for the past 7 yr. The trade-off between full disk observations and spatial resolution means that HMI is not adequate for analyzing the smallest-scale events in the solar atmosphere. Aims. Our aim is to develop a new method to enhance HMI data, simultaneously deconvolving and super-resolving images and magnetograms. The resulting images will mimic observations with a diffraction-limited telescope twice the diameter of HMI. Methods. Our method, which we call Enhance, is based on two deep, fully convolutional neural networks that input patches of HMI observations and output deconvolved and super-resolved data. The neural networks are trained on synthetic data obtained from simulations of the emergence of solar active regions. Results. We have obtained deconvolved and super-resolved HMI images. To solve this ill-defined problem with infinite solutions we have used a neural network approach to add prior information from the simulations. We test Enhance against Hinode data that has been degraded to a 28 cm diameter telescope showing very good consistency. The code is open source. [ABSTRACT FROM AUTHOR]

Fe4N thin films with (001) texture were prepared by reactive sputtering on MgO substrates, utilizing either a Cr or Ag buffer layer to facilitate the epitaxial growth. X-ray diffraction, atomic force microscopy, and vibrating sample magnetometry measurements show that the Fe4N thin film grown on the Ag buffer layer is superior to that grown on the Cr buffer layer. The point contact Andreev reflection measurement was then conducted, and the spin polarizations were determined to be 61.1% and 81.3% for Fe4N thin films with Cr and Ag buffer layers, respectively. The 81.3% spin polarization is significantly higher than the ratio reported previously for Fe4N and is comparable with that of state-of-the-art Heusler alloys. This result is in agreement with the theoretical prediction on the discrepancy between the two differently defined spin polarizations for Fe4N. Moreover, our study indicates that an optimized growth process for Fe4N thin films is crucial for achieving a high spin polarization and that true half-metallicity could potentially be realized with Fe4N. The high spin polarization of Fe4N combined with its low fabrication temperature and simple composition makes Fe4N a competitive candidate to be a half-metallic ferromagnet in spintronic devices. [ABSTRACT FROM AUTHOR]

The ZnO film deposited at room temperature, which is composed of the amorphous-phase background plus a few nanograins or nanoclusters (about 1–2 nm), exhibits room temperature ferromagnetism (FM). Such FM is found to be connected with oxygen vacancies. For the Ta/ZnO/Pt device based on the medium layer ZnO deposited at room temperature, the saturation magnetization not only is modulated between high and low resistive states by electric voltage with DC loop electric current but also increases/decreases through adjusting the magnitudes of positive/negative DC sweeping voltage. Meanwhile, the voltage-controlled conductance quantization is observed in Ta/ZnO/Pt, accompanying the voltage-controlled magnetization. However, the saturation magnetization of the Ta/ZnO/Pt device becomes smaller under positive electric voltage and returns in some extent under negative electric voltage, when the DC loop electric current is not applied. [ABSTRACT FROM AUTHOR]

On-line wear debris monitoring is a useful technology for real-time machine wear condition monitoring but needs further development. This study, based on previous developments of an on-line visual ferrograph (OLVF), focused on (i) data reconstruction for extracting representative and reliable wear condition related characteristics, and (ii) development of an improved model for on-line wear prediction. Wear monitoring of a diesel engine was performed using this on-line wear debris monitoring system. Experimental results and comparisons between the improved relevance vector machine (RVM) model and other models show that the improved RVM model gives an earlier warning and enhances the prediction accuracy. [ABSTRACT FROM AUTHOR]

In the present time, need of biogenic lubricants is the focusing area which will be biodegradable, avirulent and eco-friendly. Current experimental tests depict the effect of ‘Phyllanthus emblica’ a non-edible feedstock through pin on disc tribo tester. Tests were conducted to evaluate the impact of 0, 10, 20 and 30 % blending of Phyllanthus emblica with SAE20W40 lubricating oil on cylinder liner and piston ring. Promising results have been manifested with 10 % blending of biodiesel (BD) with lubricating oil in terms of coefficient of friction and specific wear rate in comparison with other examined feedstock. For analysis of wear debris in the used oil analytical ferrography was also done. The effects of temperature on wear and friction characteristics have also been discussed. [ABSTRACT FROM AUTHOR]

Edges are one of the most important features of wear particles in a ferrograph image and are widely used to extract parameters, recognize types of wear particles, and assist in the identification of the wear mode and severity. Edge detection is a critical step in ferrograph image processing and analysis. Till date, there has been no single algorithm that guarantees the production of good quality edges in ferrograph images for a variety of applications. Therefore, it is desirable to have a reliable evaluation method for measuring the performance of various edge detection algorithms and for aiding in the selection of the optimal parameter and algorithm for ferrographic applications. In this paper, a new non-reference method for the objective evaluation of wear particle edge detection is proposed. In this method, a comprehensive index of edge evaluation is composed of three components, i.e., the reconstruction based similarity sub-index between the original image and the reconstructed image, the confidence degree sub-index used to show the true or false degree of the edge pixels, and the edge form sub-index that is used to determine the direction consistency and width uniformity of the edges. Two experiments are performed to illustrate the validity of the proposed method. First, this method is used to select the best parameters for an edge detection algorithm, and it is then used to compare the results obtained using various edge detection algorithms and determine the best algorithm. Experimental results of various real ferrograph images verify the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Wear debris analysis (WDA) is an effective machine health monitoring technique in which wear debris attributes can reveal wear mechanisms and particle colours can be used to detect oxidation. However, most of the existing approaches to WDA are based on analytical ferrography. Online wear debris typing is still difficult to achieve because of the low resolution of online particle images. In this work, a hybrid search-tree discriminant technique is described. It permits identification of online wear particles by combining their colour attributes and multi-view particle features. A multi-class support vector data description multi-SVDD, the K-means and a support vector machine SVM are integrated to establish a three-level search-tree model to discriminate multivariate wear debris including red and black oxides, cutting, spherical, fatigue and sliding particles. First, the oxides are identified based on their special colour information using the multi-SVDD. Second, the K-means is used to look for the clustering centres of cutting and spherical particles by utilizing their distinct features of aspect ratio and sphericity. The third level built by SVM is adopted to distinguish fatigue and sliding particles based on their height aspect ratio and height-to-width aspect ratio. Experiments have demonstrated that the search-tree discrimination model is effective for multivariate wear debris classification. The proposed method provides a solution to the existing problems in online wear particle identification for wear mechanism analysis. [ABSTRACT FROM AUTHOR]

As an essential part of engine health monitoring (EHM), online lubrication oil debris monitoring has recently received great attention for the assessment of rotating and reciprocating parts in aero-engines, due to its high integration, low cost and safe characteristics. However, it is be a challenge to find a suitable sensor operating in such a complex environment. We present an unconventional novel approach, in which a cylinder capacitive sensor is designed and integrated with the pipeline of an engine lubrication system, so that the capacitive sensor can effectively detect changes in the lubrication oil condition. In this paper, an attempt to illustrate the performance characteristics of the developed cylinder capacitive sensor is made, through an experiment system that simulates a real scenario of a lubrication oil system. The main aim of the research was to qualitatively describe the relationship between the sensor parameter and the lubrication oil debris. In addition, the effect of the temperature and flow rate of the lubrication oil on capacitance change was performed by several experiments and we figured out a compensation method. The experimental results demonstrated that the cylinder capacitive sensor can potentially be used for lubrication oil debris monitoring of the health condition of an aero-engine. [ABSTRACT FROM AUTHOR]

Biodiesel can be considered to be the most capable alternate fuel for partial or complete replacement of the fossil fuel. Previous studies on biodiesel-oil blends have demonstrated that the use of double biofuels in engine can be a promising aspect for the complete elimination of diesel from compression-ignition (CI) engines. But its use increases the lubricating oil dilution to some extent due to the chemistry of biodiesel. The present experimental investigation describes the effect of biodiesel-oil blend, oxidized biodiesel-oil blend and diesel dilution in the engine oil by means of high frequency reciprocating rig (HFRR) and pin on disc (POD) friction monitor. Moreover, fresh lubricating oil, lubricating oil which was turned out from AB70EU30 operated engine with modified parameters after 100 h and lubricating oil which was turned out from diesel operated engine after 100 h were also considered for experimentation for clear comparison in results. The effects of engine oil dilution were studied on cylinder liner and piston ring as well as on cam and tappet on valve train. The present study revealed that the 10% dilution of biodiesel-oil blend in lubricating oil shows promising result in terms of coefficient of friction and diameter of wear scar as compared to other tested feedstocks. The effect of oxidation of the biodiesel-oil blend on the performance of engine oil is also assessed in the present study. Analytical ferrography of the used oil was also done to study the wear debris in oil. [ABSTRACT FROM AUTHOR]

The consciousness of deteriorating fossil fuels and the adverse impact of its consumption on human health have diverted the research towards alternate energy sources. Biodiesel seems to be the best promising alternate fuel for diesel engines as it has potential to partially or completely eliminate diesel from compression ignition (CI) engine. Several investigations on performance and emissions had shown that use of double biofuels (biodiesel-oil blends) have ability to completely replace diesel. But, the lubricating properties of fuel also affect the performance of engine as some engine parts are lubricated by the fuel itself. In the present study, effects of concentration of biodiesel in blend, temperature and load on friction and wear are investigated with the help of four ball tester. As biodiesel is subjected to oxidation and has highly affected lubricity at higher temperature and load, so the effect of oxidation was also studied. The operating loads and temperatures were 147–392 N and 45–60–75 °C respectively. During operation of four ball wear monitor, frictional torque was recorded with the help of data acquisition system. The scars on the balls are investigated with the help of microscope. An analytical ferrography was also done to analyze the wear debris in the used oil after each test. It was found out from the present investigation that the operating parameters collectively affect the lubricity. [ABSTRACT FROM AUTHOR]

Because wear is one of the most typical causes of decreasing performance in running machines, monitoring wear is regarded as a crucial technology in maintaining the health of machines. However, monitoring wear is not a fully mature process because quantifying the development of wear in real time is a challenging task because there is no universal indicator. To meet this need, wear-oriented dynamic modeling with online ferrographic images was used to investigate and then describe a real-time wear state. This investigation was carried out by combining three wear indices to describe the wear rate, the wear mechanism, and the severity of wear. A binary classifier method is also proposed to classify these wear stages in the three extracted indices. A strategy to identify the dynamic transition of wear states with adaptive parameters is also developed and then a four-ball wear test is carried out to verify the method. The results indicate that this modeling strategy can accurately identify a developing wear state that is characterized by stages. This proposed method is better at monitoring the health evolution of a machine system than just detecting faults. [ABSTRACT FROM AUTHOR]

The internal friction torque measurements in Cylindrical Roller Thrust Bearings (RTB) lubricated with axle gear oils under boundary film conditions were performed using an axial rolling bearing test rig generating tribofilms. The X-ray photoelectron spectroscopy (XPS) was used to characterize the tribofilms formed on the bearing rollers and raceways. After the tests, wear debris were found on the oil samples which lubricated the surface of the roller bearing raceways for that surface topography measurements and oil analysis (ferrography) were mandatory to measure and to visualize the occurring wear. The results obtained indicate that axle gear oil formulations and their additive packages have got a significant influence in controlling roller bearing friction and wear under boundary film lubrication. [ABSTRACT FROM AUTHOR]

Bone cells are damaged by wear particles originating from total joint replacement implants. We investigated Mesenchymal stem cells (MSCs) nanomechanical properties when exposed to cobalt and titanium nanoparticles (resembling wear debris) of different sizes for up to 3 days using AFM nanoindentation; along with flow-cytometry and MTT assay. The results demonstrated that cells exposed to increasing concentrations of nanoparticles had a lower value of elasticity and spring constant without significant effect on cell metabolic activity and viability but some morphological alteration (bleeping). Cobalt induced greater effects than titanium and this is consistent with the general knowledge of cyto-compatibility of the later. This work demonstrates for the first time that metal nanoparticles do not only influence MSCs enzymes activity but also cell structure; however, they do not result in full membrane damage. Furthermore, the mechanical changes are concentration and particles composition dependent but little influenced by the particle size. [ABSTRACT FROM AUTHOR]

Effects of electrostatic field on the macrophage responses induced by ultra-high molecular weight polyethylene (UHMWPE) wear particles have been investigated in this study. An inverted cell culture system was applied to study the interactions between UHMWPE wear particles and macrophage cells. The electrostatic field induced device (EFID) was installed on the cell culture system. The high voltage and low current stimulations generated from EFID were first applied to the UHMWPE particles/macrophage co-culture system. The proliferation and tumor necrosis factor-alpha, interleukin (IL)-6, and IL-1β cytokine expressions of J774A.1 macrophage cells were analyzed. The EFID applied voltage of 0.5 kV, 1.0 kV, 1.3 kV, and 1.6 kV were investigated. Our result indicated that the 0.5 kV and 1 kV voltages increased the proliferation of macrophage cells and activated the expression of related cytokines under the co-culture of UHMWPE wear particles. However, with the increasing applied voltage of 1.3 kV and 1.6 kV, the inhibition of the macrophage proliferation and expression of immunological cytokines were observed. There exists a critical applying EFID voltage to modulate the UHWMPE particle induced immune responses. The electrostatic field induced device presents a potential non-invasive therapy for particle induced bone resorption and osteolysis. [ABSTRACT FROM AUTHOR]

The aim of this work is to map the wear debris concentration with wear rate. A wear debris attenuation function is proposed to depict quantitatively the removal of wear debris. The total residual mass of wear debris in lubrication systems can be stated as the convolution of the wear rate and the wear debris attenuation function. Additionally, the dynamic responses of the wear debris concentration under different wear rate excitations are also presented. To simulate and verify how the debris concentration changes, an oil lubrication system test rig is built, and on-line visual ferrograph (OLVF) is used to monitor the debris concentration. Two experimental results indicate that the variation of the wear debris concentration is consistent with the model result. [ABSTRACT FROM AUTHOR]

The morphology of wear particles reflects the complex properties of wear processes involved in particle formation. Typically, the morphology of wear particles is evaluated qualitatively based on microscopy observations. This procedure relies upon the experts’ knowledge and, thus, is not always objective and cheap. With the rapid development of computer image processing technology, neural network based on traditional gradient training algorithm can be used to recognize them. However, the feedforward neural network based on traditional gradient training algorithms for image segmentation creates many issues, such as needing multiple iterations to converge and easy fall into local minimum, which restrict its development heavily. Recently, extreme learning machine (ELM) for single-hidden-layer feedforward neural networks (SLFN) has been attracting attentions for its faster learning speed and better generalization performance than those of traditional gradient-based learning algorithms. In this paper, we propose to employ ELM for ferrography wear particles image recognition. We extract the shape features, color features, and texture features of five typical kinds of wear particles as the input of the ELM classifier and set five types of wear particles as the output of the ELM classifier. Therefore, the novel ferrography wear particle classifier is founded based on ELM. [ABSTRACT FROM AUTHOR]

Context. Coronal dimmings are regions of decreased extreme-ultravoilet (EUV) and/or X-ray (originally Skylab, then Yohkoh/SXT) intensities, which are often associated with flares and coronal mass ejections (CMEs). The large-scale impulsive dimmings have been thoroughly observed and investigated. The pre-flare dimmings before the flare impulsive phase, however, have rarely been studied in detail. Aims. We focus on the pre-flare coronal dimmings. We report our multiwavelength observations of the GOES X1.6 solar flare and the accompanying halo CME that was produced by the eruption of a sigmoidal magnetic flux rope (MFR) in NOAA active region (AR) 12158 on 2014 September 10. Methods. The eruption was observed by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO). The photospheric line-of-sight magnetograms were observed by the Helioseismic and Magnetic Imager (HMI) on board SDO. The soft X-ray (SXR) fluxes were recorded by the GOES spacecraft. The halo CME was observed by the white-light coronagraphs of the Large Angle Spectroscopic Coronagraph (LASCO) on board SOHO. Results. About 96 min before the onset of the flare/CME, narrow pre-flare coronal dimmings appeared at the two ends of the twisted MFR. They extended very slowly, with their intensities decreasing with time, while their apparent widths (8-9 Mm) continued to be nearly constant. During the impulsive and decay phases of flare, typical fan-like twin dimmings appeared and expanded, with a much larger extent and lower intensities than the pre-flare dimmings. The percentage of the 171 Å intensity decrease reaches 40%. The pre-flare dimmings are most striking in 171, 193, and 211 Å with formation temperatures of 0.6-2.5 MK. The northern part of the pre-flare dimmings could also be recognized in 131 and 335 Å. Conclusions. To our knowledge, this is the first detailed study of pre-flare coronal dimmings; they can be explained by density depletion as a result of the gradual expansion of the coronal loop system surrounding the MFR during the slow rise of the MFR. [ABSTRACT FROM AUTHOR]

Thirty small-scale structures in the solar atmosphere, i.e., facula nodes at ±(20°-46°) latitudes, have been studied in order to analyze quasi-periodic variations in the magnetic field. SDO/HMI magnetograms have been used for this purpose. Long-period variations in the magnetic field strength of the considered objects in the 60-280 min range have been revealed as a result of data processing. It has been shown that there are no dependences between the magnetic field and period, nor between the magnetic field and object area. It has been assumed that the discovered variations are not natural oscillations of the magnetic field strength. [ABSTRACT FROM AUTHOR]

The paper discusses the results of the forecast of solar wind parameters at a distance of 1 AU made according to observations made by the STOP telescope magnetograph during 2014-2015. The Wang-Sheeley-Arge (WSA) empirical model is used to reconstruct the magnetic field topology in the solar corona and estimate the solar wind speed in the interplanetary medium. The proposed model is adapted to STOP magnetograph observations. The results of the calculation of solar wind parameters are compared with ACE satellite measurements. It is shown that the use of STOP observations provides a significant correlation of predicted solar wind speed values with the observed ones. [ABSTRACT FROM AUTHOR]

We present the photospheric energy density of magnetic fields in two solar active regions (one of them recurrent) inferred from observational vector magnetograms, and compare it with other available differently defined energy parameters of magnetic fields in the photosphere. We analyze the magnetic fields in Active Regions NOAA 6580-6619-6659 and 11158. The quantity $\frac{1}{4\pi}{\mathbf{B}}_{n}\cdot{\mathbf{B}}_{p}$ is an important energy parameter that reflects the contribution of magnetic shear to the difference between the potential ( $\mathbf{B}_{p}$ ) and the non-potential magnetic field ( $\mathbf{B}_{n}$ ), and also the contribution to the free magnetic energy near the magnetic neutral lines in the active regions. It is found that the photospheric mean magnetic energy density shows clear changes before the powerful solar flares in Active Region NOAA 11158, which is consistent with the change in magnetic fields in the flaring lower atmosphere. [ABSTRACT FROM AUTHOR]

Purpose The paper aims to monitor the condition of heavy Earth-moving machines (HEMMs) used in open cast mines by lube oil analysis.Design/methodology/approach Oil samples at periodic interval were collected from the HEMM engine (Model No: BEML BH50M). Ferrography and Field Emission Scanning Electron Microscopy have been used for the wear particle analysis present in oil samples. Viscosity analysis and Fourier transform infrared spectroscopy have been done to investigate the degradation in quality and changes as compared to the initial structural properties of the lubricants.Findings The results obtained indicates wear in cylinder liner and piston ring. Copper, cast iron, alloy steel and ferrous oxide have been found as rubbing wear particles and cutting wear particles. Contamination level has also been found to be increasing in consecutive older oil samples. Chemical properties degraded with usage time and variations in oxidation and soot level have also been observed in every sample.Practical implications The results will be very much useful to maintenance teams of mining industry for early prediction of any impending failure of the machines, for example, diesel dilution, severe wear of the piston or cylinder liner leading to seizure can be predicted.Originality/value The HEMMs are an important piece of equipment in coal mining. Proper condition monitoring of HEMM is required to reduce the break down and down time to increase production. [ABSTRACT FROM AUTHOR]

A combination of analytical calculations and vectormagnetogram data is utilized to develop a nonaxisymmetric non-force-free magnetic field and assess its viability in describing solar active regions. For that purpose, we construct a local spherical shell where a planar surface, tangential to the inner sphere, represents a Cartesian cutout of an active region. The magnetic field defined on the surface is then correlated with magnetograms. The analysis finds that the non-axisymmetric non-force-free magnetic field, obtained by a superposition of two linear-force-free fields, correlates reasonably well with magnetograms. [ABSTRACT FROM AUTHOR]

Presents a study that determined the nucleation of the uniform rotation mode for uniaxial ferromagnets including the second anisotropy constant K[sub2]. Value of K[sub2]; Effect of the value on the hysteresis loop and nucleation field; Use of modified astroids to analyze the angular dependence of hysteresis loop.

Reports on the application of vertical anisotropy media configuration to magnetography to improve the resolution in the inking of the dots. Deposition conditions in the planar and cylindrical configurations; Scheme of the vacuum chamber for the cylindrical configuration radio frequency sputtering group; Illustration of a typical x-ray diffraction.

Liquid biopsies hold enormous promise for the next generation of medical diagnoses. At the forefront of this effort, many are seeking to capture, enumerate and analyze circulating tumor cells (CTCs) as a means to prognosticate and develop individualized treatments for cancer. Capturing these rare cells, however, represents a major engineering challenge due to their low abundance, morphology and heterogeneity. A variety of microfluidic tools have been developed to isolate CTCs from drawn blood samples; however, few of these approaches offer a means to separate and analyze cells in an integrated system. We have developed a microfluidic platform comprised of three modules that offers high throughput separation of cancer cells from blood and on-chip organization of those cells for streamlined analyses. The first module uses an acoustic standing wave to rapidly align cells in a contact-free manner. The second module then separates magnetically labeled cells from unlabeled cells, offering purities exceeding 85% for cells and 90% for binary mixtures of synthetic particles. Finally, the third module contains a spatially periodic array of microwells with underlying micromagnets to capture individual cells for on-chip analyses (e.g., staining, imaging and quantification). This array is capable of capturing with accuracies exceeding 80% for magnetically labeled cells and 95% for magnetic particles. Overall, by virtue of its holistic processing of complex biological samples, this system has promise for the isolation and evaluation of rare cancer cells and can be readily extended to address a variety of applications across single cell biology and immunology. [ABSTRACT FROM AUTHOR]

We analyzed how sensitivity and accuracy in solar magnetic field measurements may affect the values of mean current helicity density $h_{\mathrm{c}}$ and twist parameter $\alpha_{\mathrm{av}}$ by comparing these values obtained from two magnetographs (SMFT at Beijing and SFT at Mitaka, Tokyo). When we computed the helicity parameters from the SFT data, we replaced the values of the longitudinal field component, transverse field strength, and transverse field azimuth angle with those from the SMFT data and examined the differences. The results show that the correlation coefficient and the fraction of the data that agree in signs of $h_{\mathrm{c}}$ or $\alpha_{\mathrm{av}}$ increase when an SFT parameter is substituted by the corresponding SMFT parameter because one source of discrepancy is removed. The increase in correlation coefficient is largest when the azimuthal angles and transverse field strengths are set identical in the two instruments; the correlation coefficient of $h_{\mathrm{c}}$ ( $\alpha_{\mathrm{av}}$ ) increases from 0.74 (0.56) to 0.86 (0.78), respectively, indicating that the differences in the transverse field strength and its azimuthal angle are the largest source of discrepancy in the values of $h_{\mathrm{c}}$ or $\alpha_{\mathrm {av}}$ . We found a nonlinear relationship in the components of the magnetic field between the two instruments for some data samples; we conclude that this is due to the discrepancy in the calibration procedure between the two instruments. This nonlinearity can be another source of difference in determining helical parameters between the two instruments. [ABSTRACT FROM AUTHOR]

Previous studies have shown that the variation over the solar magnetic activity cycle of the area of facular/network features identified from broad-band and narrow-band imagery is positively correlated with the sunspot area and number, the relation being described as either linear or quadratic. On the other hand, the temporal variation of the spatial distributions of faculae, network and sunspots follows patterns that are less obviously correlated, so that we expect the relation that describes variation of the area coverage of different types of magnetic features to vary with the position over the disk. In this work we employ Michelson Doppler Interferometer (MDI) full-disk magnetograms acquired during solar cycle 23 and at the beginning of cycle 24 to investigate the relation between the coverage of magnetic elements characterized by different amounts of magnetic flux and located at different angular distances from disk center with the sunspot number. In agreement with some previous studies we find that daily data are best described by a quadratic function while data averaged over six months are best described by a linear function. In both cases the coefficients of the fits show large dependence on the position over the disk and the magnetic flux. We also find that toward disk center six-month averaged data show asymmetries between the ascending and the descending phases. The implications for solar irradiance modeling are discussed. [ABSTRACT FROM AUTHOR]

The wear process in a sliding contact results in generation of wear debris, which affects the system life. The impact depends on the wear particle properties, such as size, shape and number. In this paper, the wear particles formed during a cylinder-on-disk wear test were examined. PAO additive-free oil, steel-brass and steel-steel contact pairs were employed. A particle isolation procedure was applied, and SEM/EDS analysis was used to validate it. DLS measurements indicated the wear particles radius to be in the range from 230 to 260 nm for both materials under applied nominal pressures from 87 to 175 MPa. AFM data revealed the wear particles size to be in the range from 133 to 175 nm. A slight increase in particles size with load was observed by AFM for both materials and confirmed by DLS for steel samples. AFM measurements were taken to determine thickness, length and width distributions of the wear particles. The number of wear particles per sliding distance and per unit load was estimated to be in the range from $$150$$ to $$750\, \frac{\text{particles}}{{{\text{mm}}\,{\text{N}}}}$$ for steel and approximately 1600-1900 $$\frac{\text{particles}}{{{\text{mm}}\,{\text{N}}}}$$ for brass. [ABSTRACT FROM AUTHOR]

Aimed at the correct segmentation of wear particles in ferrograph images, a new method combining marker-controlled watershed and an improved grey clustering algorithm is proposed in this article. First, the marker-controlled watershed is applied to ferrograph images to efficiently obtain the initial segmentation of wear particles. Then, an improved grey clustering algorithm utilizing color characteristics and relative position information is applied to merge the oversegmented regions after the watershed segmentation. This new algorithm is tested for ferrograph images and the results are compared with those of other algorithms. The experimental results show that the proposed method is effective for the segmentation of large wear particles and fine wear debris deposited as chains on the ferrograph, and it is proven to be a practical method for segmenting wear particles quickly and accurately. [ABSTRACT FROM PUBLISHER]

Tribological properties of the working surfaces under damped harmonic excitation (DHE) loading are experimentally evaluated. Tribological tests under DHE loading produced by a spring-connecting weight system were capable to monitor friction with a force sensor and to analyze wear processes by an on-line visual ferrography system, respectively. Effects of different spring-connecting loads and various excitation intervals on the tribological behavior were investigated. Results indicated the existence of an appropriate spring-connecting load to give low coefficient of friction. High excitation frequency could help to accelerate the early completion of running-in process, but long excitation intervals could aggravate wear rate in the running-in period. Main surface damages or wear modes were identified as the consequence of fatigue, side flow, and plowing to generate grooves under various DHE loadings. [ABSTRACT FROM AUTHOR]

G-band bright points (GBPs) are regarded as good manifestations of magnetic flux concentrations. We aim to investigate the relation between the dynamic properties of GBPs and their longitudinal magnetic field strengths. High spatial and temporal resolution observations were recorded simultaneously with G-band filtergrams and Narrow-band Filter Imager (NFI) Stokes $I$ and $V$ images with Hinode/ Solar Optical Telescope. The GBPs are automatically identified and tracked in the G-band images, and the corresponding longitudinal magnetic field strength of each GBP is extracted from the calibrated NFI magnetograms by a point-to-point method. After categorizing the GBPs into five groups by their longitudinal magnetic field strengths, we analyzed the dynamics of each group of GBPs. The results suggest that with increasing longitudinal magnetic field strengths of GBPs correspond to a decrease in their horizontal velocities and motion ranges as well as by showing more complex motion paths. This suggests that magnetic elements showing weaker magnetic field strengths move faster and farther along straighter paths, while stronger elements move more slowly in more erratic paths within a smaller region. The dynamic behaviors of GBPs with different longitudinal magnetic field strengths can be explained by that the stronger flux concentrations withstand the convective flows much better than weaker ones. [ABSTRACT FROM AUTHOR]

The basic observational properties of “coronal partings”—the special type of quasi-one-dimensional magnetic structures, identified by a comparison of the coronal X-ray and EUV images with solar magnetograms—are investigated. They represent the channels of opposite polarity inside the unipolar large-scale magnetic fields, formed by the rows of magnetic arcs directed to the neighboring sources of the background polarity. The most important characteristics of the partings are discussed. It can be naturally assumed that—from the evolutionary and spatial points of view—the partings can transform into the coronal holes and visa versa . The classes of global, intersecting, and complex partings are identified. [ABSTRACT FROM AUTHOR]

Purpose – This paper aims to optimize the operating condition of mechanical parts, whose working surfaces have macro-crack defects, and surface wear properties with macro-cracks are assessed through experimental investigation. Design/methodology/approach – Macro-cracks perpendicular to the direction of sliding were manufactured on discs by electric discharge machining. Tribological tests under oil lubrication were conducted on a ball-on-disc test rig. Their wear processes were monitored with on-line visual ferrography. The cross-sectional profile and morphology of the wear track were analyzed using a T200 profilometer and a scanning electron microscope, respectively. Effects of different crack numbers and various applied normal loads on the wear behavior were studied. Findings – The macro-cracks tend to promote plastic deformation on the contact disc surfaces, and material plastic deformation of the crack edges varies with the magnitude of applied normal loads. Relationship of the duration of running-in period and root mean square index of the particle coverage area with the numbers of crack is approximately linear. Originality/value – The wear properties of surfaces with macro-cracks were assessed with various crack numbers and with different applied normal loads, and the relationship between the index of particle coverage area and the wear rate was established. [ABSTRACT FROM AUTHOR]

The electric current helicity density ... contains six terms, where bi are components of the magnetic field. Due to the observational limitations, only four of the above six terms can be inferred from solar photospheric vector magnetograms. By comparing the results for simulation we distinguished the statistical difference of above six terms for isotropic and anisotropic cases. We estimated the relative degree of anisotropy for three typical active regions and found that it is of order 0.8 which means the assumption of local isotropy for the observable current helicity density terms is generally not satisfied for solar active regions. Upon studies of the statistical properties of the anisotropy of magnetic field of solar active regions with latitudes and with evolution in the solar cycle, we conclude that the consistency of that assumption of local homogeneity and isotropy requires further analysis in the light of our findings. [ABSTRACT FROM AUTHOR]

Eruptions, flares, and coronal mass ejection (CMEs) are due to physical phenomena mainly driven by an initially force-free current-carrying magnetic field. We review some key observations relevant to the current theoretical trigger mechanisms of the eruption and to the energy release via reconnection. Sigmoids observed in X-rays and UV, as well as the pattern (double J-shaped) of electric currents in the photosphere show clear evidence of the existence of currents parallel to the magnetic field and can be the signature of a flux rope that is detectable in CMEs. The magnetic helicity of filaments and active regions is an interesting indirectly measurable parameter because it can quantify the twist of the flux rope. On the other hand, the magnetic helicity of the solar structures allows us to associate solar eruptions and magnetic clouds in the heliosphere. The magnetic topology analysis based on the 3D magnetic field extrapolated from vector magnetograms is a good tool for identifying the reconnection locations (null points and/or the 3D large volumes - hyperbolic flux tube, HFT). Flares are associated more with quasi-separatrix layers (QSLs) and HFTs than with a single null point, which is a relatively rare case. We review various mechanisms that have been proposed to trigger CMEs and their observable signatures: by 'breaking' the field lines overlying the flux rope or by reconnection below the flux rope to reduce the magnetic tension, or by letting the flux rope to expand until it reaches a minimum threshold height (loss of equilibrium or torus instability). Additional mechanisms are commonly operating in the solar atmosphere. Examples of observations are presented throughout the article and are discussed in this framework. [ABSTRACT FROM AUTHOR]