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This article investigates the consequences of using Singular Spectral Analysis (SSA) to construct a time series bootstrap. The bootstrap replications are obtained via a SSA decomposition obtained using rescaled trajectories (RT‐SSA), a procedure that is particularly useful in the analysis of time series that exhibit nonlinear, non‐stationary and intermittent or transient behaviour. The theoretical validity of the RT‐SSA bootstrap when used to approximate the sampling properties of a general class of statistics is established under regularity conditions that encompass a very broad range of data generating processes. A smeared and a boosted version of the RT‐SSA bootstrap are also presented. Practical implementation of the bootstrap is considered and the results are illustrated using stationary, non‐stationary and irregular time series examples. [ABSTRACT FROM AUTHOR]

As quantum computing advances rapidly, guaranteeing the security of cryptographic protocols resistant to quantum attacks is paramount. Some leading candidate cryptosystems use the learning with errors (LWE) problem, attractive for its simplicity and hardness guaranteed by reductions from hard computational lattice problems. Its algebraic variants, ring-learning with errors (RLWE) and polynomial learning with errors (PLWE), gain efficiency over standard LWE, but their security remains to be thoroughly investigated. In this work, we consider the “smearing” condition, a condition for attacks on PLWE and RLWE introduced in Elias et al. We expand upon some questions about smearing posed by Elias et al. and show how smearing is related to the coupon collector’s problem. Furthermore, we develop an algorithm for computing probabilities related to smearing. Finally, we present a smearing-based algorithm for solving the PLWE problem.

This paper discusses the adhesive wear type "smearing" in small radial cylindrical roller bearings with combined axial and radial load. A reference test with high radial and axial static load leads to reproducible smearings. The impact of speed, starting oil temperature, axial and radial load as well as running-in is investigated with a seperate parameter variation. The measurement of the roller and roller set slip together with the damage analysis enables the distinction between roller-roller and roller-ring smearing. [ABSTRACT FROM AUTHOR]

This study reveals mineral and deformation processes associated with faulting of lacustrine unconsolidated sediments in the Guadix-Baza Basin (Betic Cordillera, S Spain) affected by the Baza Fault. Brittle carbonate and silt sediments develop deformation bands frequently sealed by dolomite crystallization, whereas ductile clay-rich sediments form clay smearing bands where late crystallization of gypsum can be observed. Granular flow and local cataclasis were the main deformation mechanisms in the brittle deformation bands. Flow alignment, grain-boundary sliding, and extrusion were predominant in the clay smearing bands. These water and clay-rich bands reduced shear strength of the faulting process due to their lubricating effect. Beidellitic smectite defines shear foliation of the smeared bands, but Mg-Fe, a K-rich smectite (Fe + Mg > 1 and K content up to 0.8 a.p.f.u), crystallizes in the micropores surrounding brittle clasts produced by deformation pressure shadows. These data suggest that the interaction of micromechanical events, which increased sediment porosity by the generation of pressure shadows, and the flow and concentration of saline fluids in these pores promoted structural diagenesis processes that favoured the beginning of local illitization. [ABSTRACT FROM AUTHOR]

Room-temperature afterglow (RTA) materials have a wide range of applications in imaging, lighting, and therapy, due to their long lifetime and persistent luminescence after the light source is removed. Additionally, near-infrared light with low energy and a high penetration rate ensures its irreplaceable importance in imaging and therapy. Thus, it is vital to design RTA materials excited by NIR. In the present study, we select up-conversion nanoparticles (UCNPs) as the donor and add them into hybrids, obtained by dispersing coronene tetra-carboxylate salt (CS) into a polyvinyl alcohol (PVA)-substrate through a series of mixing methods. Through radiation energy transfer between the donor UCNPs and the acceptor CS, a kind of RTA film with a photoluminescence lifetime of more than 2 s under NIR excitation was successfully achieved, and these films could maintain persistent naked-eye-distinguishable luminescence after withdrawing the excitation light source. Furthermore, the films obtained from UCNP doping into CS/PVA hybrids were found to exhibit better RTA performance than those from smearing. This idea of up-conversion afterglow broadens the tuning and application scope for polymer-based luminescent materials. [ABSTRACT FROM AUTHOR]

A previously developed model for heavily loaded Elastohydrodynamically lubricated (EHL) contacts with surface micro-geometry for the calculation of surface distress (micropitting), based on high-cycle fatigue and mild wear competition, is herewith further extended. It now includes the effects of frictional heating with a sharp temperature rise developed in the rolling contact. For this, a new surface damage model, originated in creep modelling, is included. With this modification, the detrimental effect of high temperature developed in the rolling/sliding contact can now be accounted for. This model can consider sharp or moderate surface temperature rise during over-rolling is found in bearings and gears operating at high speeds or under the combination of speeds, loads and unfavourable environmental aspects. The present model introduces a threshold limit made of the combination of temperature and (heating time under stress) load cycles above which the conditions in the rolling contact are deemed damaging for the steel microstructure and the tribological functionality of the rolling contact. The surface damage model is first compared with laboratory experiments in rolling/sliding conditions and then applied to study combinations of loads, sliding speeds and the effect in rolling bearings. The ability of the present model to include damaging mechanisms, other than classical metal fatigue, increases the flexibility in contact surface damage modelling and allows for the accounting of phenomena up to now excluded from better estimation of the machine elements surface life. [ABSTRACT FROM AUTHOR]

Sediment profiling imaging (SPI) is a versatile and widely used method to visually assess the quality of seafloor habitats (e.g., around fish farms and oil and gas rigs) and has been developed and used by both academics and consultancy companies over the last 50 years. Previous research has shown that inserting the flat viewport of an SPI camera into the sediment can have an impact on particle displacement pushing oxygenated surface sediments to deeper sediment depths and making anthropogenically-disturbed sediment appear healthier than they may actually be. To investigate the particle displacement that occurs when a flat plate is inserted into seafloor sediments, a testing device, termed the SPI purpose-built sediment chamber (SPI-PUSH) was designed and used in a series of experiments to quantify smearing where luminophores were used to demonstrate the extent of particle displacement caused by a flat plate being pushed into the sediment. Here, we show that the plate of the SPI-PUSH caused significant smearing, which varied with sediment type and the luminophore grain size. The mean particle smearing measured directly behind the inserted plate was 2.9 ± 1.5 cm for mud sediments with sand-like luminophores, 4.3 ± 2.5 cm for fine sand sediments with sand-like luminophores and 1.9 ± 1.1 cm for medium sand sediments with mud-like luminophores. When the mean depth of particle smearing was averaged over a larger sediment volume (11 cm3) next to the inserted plate, substantial differences were seen between the plate-insertion experiments and controls highlighting the potential extent of smearing artefacts that may be produced when a SPI camera penetrates the seafloor. This experimental data shows that future studies using the SPI camera, or any other periscope-like device (e.g., planar optodes) need to acknowledge that smearing may be significant. Furthermore, it highlights that a correction factor may need to be applied to these data (e.g., the depth of apparent redox potential discontinuity layer) to correctly interpret SPI camera images and better determine the effect of anthropogenic impacts on seafloor habitats.

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Copyright of Tribologie und Schmierungstechnik is the property of Narr Francke Attempto Verlag GmbH & Co.KG and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Many mechanical components require mirror–like surface appearance. When the application concerns the manufacturing of steel dies and moulds, material removal processes are the preferential choice in order to achieve the wanted dimensions and surface topography. In particular, ball milling is used in all those cases that require the machining of free form surfaces. When mirror-like surface appearance is in focus in such components, the final machining operations consists in a very shallow cut. The theoretical surface roughness (kinematic surface topography) that can be achieved in a finishing operation by ball end milling is orders of magnitude below the actual surface roughness. Beside runout and machine tool positioning errors, the quality of the cutting tools is a key factor in determining the surface topography. The combination of shallow depth of cut together with the finite size of the cutting edge radius of the tool are responsible for the occurrence of material smearing phenomena. Smearing, consisting in the accumulation of plastically deformed material over the surface, is particularly detrimental for the aesthetic functionality of machined components because it is responsible of the "foggy" appearance. In order to minimize the occurrence of the smeared material it is necessary to have a good understanding of the causes of the smearing formation process. The aim of this paper is the description and quantification of the smearing phenomena for ball end milling operations. The location of the smeared material is determined through SEM image analysis and related with the direction of the cutting speed and milling strategy. Subsequently the volume of the smeared material is quantified through a combination of confocal microscopy and SEM image analysis. Based on the volumetric analysis of the smeared material a new method for determining the Minimum Uncut Chip Thickness for the material is proposed. [ABSTRACT FROM AUTHOR]

We address a number of technical problems with the popular Practitioner Black-Scholes (PBS) method for valuing options. The method amounts to a two-stage procedure in which fitted values of implied volatilities (IV) from a linear regression are plugged into the Black-Scholes formula to obtain predicted option prices. Firstly we ensure that the prediction from stage one is positive by using log-linear regression. Secondly, we correct the bias that results from the transformation applied to the fitted values (i.e., the Black-Scholes formula) being a highly non-linear function of implied volatility. We apply the smearing technique in order to correct this bias. An alternative means of implementing the PBS approach is to use the market option price as the dependent variable and estimate the parameters of the IV equation by the method of non-linear least squares (NLLS). A problem we identify with this method is one of model incoherency: the IV equation that is estimated does not correspond to the set of option prices used to estimate it. We use the Monte Carlo method to verify that (1) standard PBS gives biased option values, both in-sample and out-of-sample; (2) using standard (log-linear) PBS with smearing almost completely eliminates the bias; (3) NLLS gives biased option values, but the bias is less severe than with standard PBS.We are led to conclude that, of the range of possible approaches to implementing PBS, log-linear PBS with smearing is preferred on the basis that it is the only approach that results in valuations with negligible bias. [ABSTRACT FROM AUTHOR]

An approach that determines the charge carrier lifetime from photoluminescence (PL) imaging that is virtually not affected by lateral charge carrier drift and diffusion and image smearing due to photon scattering is proposed. The approach attempts to create a laterally uniform charge carrier density within a sample with non‐homogeneous recombination properties via illumination with spatially varying intensity. Lateral excess charge carrier drift and diffusion is inherently absent in this situation. Furthermore, as a homogeneous PL intensity is monitored, any optical artefact induced by photon scattering in the investigated wafer or the detection charge‐coupled device is strongly suppressed compared to conventional PL imaging. Using numeric simulations of different lifetime distribution scenarios, including one based on measured micro‐photoluminescence (μ‐PL) lifetime data, we demonstrate the feasibility of this proposed “Adaptive Excitation Photoluminescence Imaging” (Ax‐PLI) method. [ABSTRACT FROM AUTHOR]

The interpretation of estimates of model parameters in terms of biological information is often just as important as the predictions of the model itself. In this study we consider the identification of metabolites in a possibly biologically heterogeneous case group that show abnormal patterns with respect to a set of (healthy) control observations. For this purpose, we filter normal (baseline) natural variation from the data by projection of the data on a control sample model: the residual approach. This step should more easily highlight the abnormal metabolites. Interpretation is, however, hindered by a problem we named the ‘residual bias’ effect, which may lead to the identification of the wrong metabolites as ‘abnormal’. This effect is related to the smearing effect. We propose to alleviate residual bias by considering a weighted average of the filtered and raw data. This way, a compromise is found between excluding irrelevant natural variation from the data and the amount of residual bias that occurs. We show for simulated and real-world examples that this compromise may outperform inspection of the raw or filtered data. The method holds promise in numerous applications such as disease diagnoses, personalized healthcare, and industrial process control. [ABSTRACT FROM AUTHOR]

Multivariate Statistical Process Control (MSPC) based on Principal Component Analysis (PCA) is a well-known methodology in chemometrics that is aimed at testing whether an industrial process is under Normal Operation Conditions (NOC). As a part of the methodology, once an anomalous behaviour is detected, the root causes need to be diagnosed to troubleshoot the problem and/or avoid it in the future. While there have been a number of developments in diagnosis in the past decades, no sound method for comparing existing approaches has been proposed. In this paper, we propose such a procedure and use it to compare several diagnosis methods using randomly simulated data and from realistic data sources. This is a general comparative approach that takes into account factors that have not previously been considered in the literature. The results show that univariate diagnosis is more reliable than its multivariate counterpart. [ABSTRACT FROM AUTHOR]

Categorical approach to probability leads to better understanding of basic notions and constructions in generalized (fuzzy, operational, quantum) probability, where observables-dual notions to generalized random variables (statistical maps)-play a major role. First, to avoid inconsistencies, we introduce three categories $\mathbb {L}$ , $\mathbb {S}$ , and $\mathbb {P}$ , the objects and morphisms of which correspond to basic notions of fuzzy probability theory and operational probability theory, and describe their relationships. To illustrate the advantages of categorical approach, we show that two categorical constructions involving observables (related to the representation of generalized random variables via products, or smearing of sharp observables, respectively) can be described as factorizing a morphism into composition of two morphisms having desired properties. We close with a remark concerning products. [ABSTRACT FROM AUTHOR]

The construction of four dikes on deep strata of very soft clay has required the application of several measures to improve the performance of the foundation, such as very wide berms, basal geotextile reinforcement and prefabricated vertical drains (PVDs). In order to control the rate of construction, the foundation and the dikes have been monitored with settlement plates, topographic stakes, inclinometers and piezometers. The use of back-analysis has allowed finding the adequate material model, the smearing of drains and the coefficient of secondary compression necessary to attain a good agreement between the measurements supplied by the instrumentation and the calculated values obtained with an elastic-viscoplastic (EVP) finite element (FE) program. Both the geotextile reinforcement and the PVDs produce an important increase in the safety factor (SF). The PVDs produce a significant acceleration in settlements, but the influence of the geotextile in the settlements is negligible. The combined use of the geosynthetic reinforcement and PVDs enhances embankment performance substantially more than the use of either method of soil improvement alone. The importance of flow in the results has been established. [ABSTRACT FROM AUTHOR]

We investigate the locality of electronic interactions in aluminum as a function of smearing/electronic temperature in the context of O ( N ) Density Functional Theory calculations. Specifically, we determine the convergence in energy and atomic forces with truncation region size for smearing of 0.001–0.15 Ha. We find exponential convergence accompanied by a rate that increases sub-linearly with smearing, with truncation region sizes of 48–64 Bohr required to achieve chemical accuracy for typical smearing values of 0.001–0.01 Ha. This translates to O ( N ) scaling for systems larger than O ( 1000 ) atoms. [ABSTRACT FROM AUTHOR]

Low-temperature superconductors are widely used in high-field magnets, mostly within Rutherford-type cables. The run for higher fields leads to greater forces on the conductor, which is pushed closer to its mechanical limit. Managing the higher strain and stress levels on the conductor supposes to perform simulation at the strand level, especially with strain-sensitive superconductors such as Nb3Sn. Three-dimensional models are necessary because inside of a magnet, the conductor is subject to a complex combination of axial and transverse loads. Superconducting cables are anisotropic composite structures that can comprise superconducting strands, insulation materials, stabilizing parts, porosities, etc. They have a multiscale architecture, the performance at the magnet scale being driven by the filament scale. This paper proposes a numerical approach for 3-D finite-element (FE) modeling of Rutherford cables, at the scale of the strand. The 3-D mesh of two reference cables is built with a simplified cable forming model. The accuracy of this geometrical model is assessed by comparing sections of the simulated mesh with tomographic data, using relevant criteria and specific geometry analysis tools. In this approach, the strand is considered as bimetallic, with a copper core, a superconducting bundle ring, and an outer copper ring. After mechanical 3-D FE computation on this bimetallic mesh, the strain/stress state on the local compounds of the strand (including Nb 3Sn filaments) is obtained by strain projection. The strain/stress state on the Nb3Sn filaments can be used to estimate the cable current transport capability, thanks to the existing scaling laws. [ABSTRACT FROM PUBLISHER]

Different aspects of the tribological performance of black oxidized surfaces in rolling–sliding boundary-lubricated or mixed lubricated contacts are overviewed in the present work. It covers the topics of antimicropitting resistance, antismearing effects, reduction in boundary friction, repelling tribochemical attacks of aggressive lubricants or additives, running-in behavior, and the effect of black oxide coating on bearing life. The results of the component laboratory experiments, full bearing tests, and theoretical modeling, performed within the frame of the present work, shed light upon the benefits and limitations of using black oxide coating for bearing applications. [ABSTRACT FROM AUTHOR]

Modern optoelectronic devices are usually based on multi-component alloys. Local statistical fluctuations in the concentrations of chemically different components cause energy fluctuations experienced by charge carriers. So far the theory for compositional disorder has been developed for compounds, in which atoms of only two chemically different types can occupy sites in a given sublattice. We extend the theoretical consideration for multi-compound alloys containing more than two chemically different semiconductor species occupying sites in the same sublattice. Different spatial dimensionalities are considered. A comparison between theoretical predictions and experimental data can be used to reveal compositional dependencies of such material parameters as the effective mass. [ABSTRACT FROM AUTHOR]

Aphids have evolved various defense strategies against natural enemies, including secretions from their cornicles. We assessed the defensive function of cornicle secretions by the goldenrod aphid, Uroleucon nigrotuberculatum (Olive), against larvae of the lady beetles Coccinella septempunctata bruckii Mulsant and Propylea japonica (Thunberg) (Coleoptera: Coccinellidae). The aphid secreted red droplets from its cornicles when attacked by the larvae. Two-thirds of the C. septempunctata bruckii larvae and 46.7% of the P. japonica larvae that preyed on the aphids died before reaching the pre-pupal stage. The secretions caused molting failure when smeared on the larvae's heads or glued to the larvae's mouthparts, killing 56.7% of C. septempunctata bruckii larvae and 36.7% of P. japonica larvae. Second instar larvae were affected most. About 40% of third and fourth instar larvae of C. septempunctata bruckii vomited soon after ingesting the aphids. In the field, up to 40% of first and second instar larvae were smeared with red secretions. Our results show that these cornicle secretions are an effective and active defense against earlier instars of coccinellid larvae. [ABSTRACT FROM AUTHOR]

We study essentially bounded quantum random variables and show that the Gelfand spectrum of such a quantum random variable ψ coincides with the hypoconvex hull of the essential range of ψ . Moreover, a notion of operator-valued variance is introduced, leading to a formulation of the moment problem in the context of quantum probability spaces in terms of operator-theoretic properties involving semi-invariant subspaces and spectral theory. As an application of quantum variance, new measures of random and inherent quantum noise are introduced for measurements of quantum systems, modifying some recent ideas of Polterovich [17] . [ABSTRACT FROM AUTHOR]

The purpose of the study is a theoretical analysis of the available types of contact traces of blood and the establishment of their occurrence at the objects of medical and forensic examinations. Contact marks are formed as a result of the mechanical interaction of two objects, one of which is stained with blood. The literature data allow us to distinguish several types of contact traces of blood: impressions, smears, smearing, «voids», traces in the form of changes in the existing stain from wiping, washing, traces-artifacts from insects. Each type has a mechanism of formation and characteristic features. We analyzed 107 archival medical and forensic examinations. In the examinations in which the material situation of the scene of the incident (5 or more objects) is maximally represented, contact traces were present in 76% of the examinations, which indicates a high occurrence. The following types of contact traces of blood were the most common: smears (29% of all examinations), smearing (22.4%) and «voids» (10.3%). Other types of contact traces were less common.

The determination of the solidification characteristics of alloys using differential scanning calorimetry (DSC) is difficult because of the unknowns associated with the kinetic of phase transformations and the thermal resistance between the sample and the temperature measuring device. This paper shows how appropriate assumptions coupled with a thermodynamic software package and an accurate mathematical analysis of a power-compensated DSC, can enable a direct comparison between the experimental and the theoretical heat evolutions obtained during the solidification of a multiphase alloy. This comparison is helpful in order to assess the thermodynamic database and to validate the different assumptions made in the solidification model. [ABSTRACT FROM AUTHOR]

The planetary roller screw mechanism is used in the aeronautics industry for electro-mechanical actuators application. It transforms a rotational movement into a translation movement, and it is designed for heavy loads. The main components are made of martensitic stainless steel, and lubricated with grease. Like most usual rolling mechanisms, smearing and jamming can occur before the theoretical fatigue lifetime, especially in defective lubrication conditions. The actuated load is carried by small contacts between the threads of the screw, the rollers and the nut. The static single contact can be described as an ellipsoid on flat contact; motion consists of rolling with sliding perpendicular to the rolling direction. A calculation method based on elastic theories (Hertz, Carter, Johnson) has been implemented. It calculates the normal and tangential stresses distributions, generated in the micro-slip and stick zones of the contact area, using several input parameters such as material properties, normal force, and creep ratio. A specific apparatus has been developed to support these calculations and to experimentally study the damage of the contacts in this mechanism. It consists of a freely rolling wheel loaded on a rotating disc with a component of sliding that simulates the roller screw contact. The tribometer inputs are the normal load, the speed, the creep ratio, and the lubrication. The wheel rolling speed and the tangential force generated in the direction perpendicular to rolling are measured. The experiments reveal a quick adhesive wear in dry or bad lubricated conditions, while a low friction coefficient remains if the contact is well lubricated. The influence of the input parameters concurs with the theoretical calculation. The evolution of grease lubrication during duty lifetime and the influence of the tribo-chemical films on this lifetime are also studied. [ABSTRACT FROM AUTHOR]

In this paper, we propose an algorithm that combines the Lüscher-Weiss (LW) multi-level error reduction technique with three-dimensional gauge-field smoothing. The purpose of this algorithm is to reduce the noise and the computational time associated with measuring field correlators in the low temperature pure quantum chromodynamics (QCD), or the stringy regions of Yang-Mills theory in general. The simultaneous application of both link-blocking and path-integral factorization techniques is based on the observation that Monte Carlo updating of the three-dimensional smeared lattices preserves the key features of the long distance physics. [ABSTRACT FROM AUTHOR]

As a part of the Computer Vision domain, layout analysis is the process through which the regions of interest from a document available as an image are being classified. A scanned file could be an example of such a document. The components of the layout analysis process are: the geometrical analysis and the logical layout. The geometrical analysis involves the detection and labeling of differing regions or blocks of the image as being text, illustration, mathematic symbols, tables etc. The logical layout refers to the detecting of the logical role that various regions have in the document (titles, footnotes, etc.). The layout analysis process is intended to be performed before the document is sent or the OCR engine but it can also be used to identify copies of the same document or for indexing documents by structure. This paper presents an approach to analyze the layout based on a voting scheme, thus combining a series of algorithms and using weighted, majority and unanimous votes, with the purpose of increasing the accuracy of the results. [ABSTRACT FROM AUTHOR]

The onset of smearing damage was studied under controlled conditions in a custom test rig that simulates the passage of a rolling element through loaded and unloaded zones of a rolling bearing. The setup includes a spherical roller that is intermittently loaded between two bearing raceways driven at a prescribed speed. The roller is free to accelerate during the loading phase. Contact load, roller speed and acceleration, and electrical contact resistance are recorded during the test. Contact shear stress, friction coefficient, frictional power intensity, and elastohydrodynamic film thickness are calculated from the recorded kinematics data. Results suggest that the first onset of smearing occurs early in the loading phase where the roller is near stationary and the frictional power intensity is high. The raceway speed at the onset of damage decreases with increasing load and increasing lubricant supply temperature. The maximum frictional power intensity is found to be relatively constant at all contact conditions that led to smearing. An existing thermomechanical contact model is used to estimate the contact temperature distribution under smearing conditions and the potential for elastohydrodynamic lubrication (EHL) film thickness reduction due to forward heat conduction. [ABSTRACT FROM AUTHOR]

We investigate methods for the design of sample surveys, and address the traditional resistance of survey samplers to the use of model-based methods by incorporating model robustness at the design stage. The designs are intended to be sufficiently flexible and robust that resulting estimates, based on the designer’s best guess at an appropriate model, remain reasonably accurate in a neighbourhood of this central model. Thus, consider a finite population of N units in which a survey variable Y is related to a q dimensional auxiliary variable x. We assume that the values of x are known for all N population units, and that we will select a sample of n≤ N population units and then observe the n corresponding values of Y. The objective is to predict the population total $T=\sum_{i=1}^{N}Y_{i}$ . The design problem which we consider is to specify a selection rule, using only the values of the auxiliary variable, to select the n units for the sample so that the predictor has optimal robustness properties. We suppose that T will be predicted by methods based on a linear relationship between Y—possibly transformed—and given functions of x. We maximise the mean squared error of the prediction of T over realistic neighbourhoods of the fitted linear relationship, and of the assumed variance and correlation structures. This maximised mean squared error is then minimised over the class of possible samples, yielding an optimally robust (‘minimax’) design. To carry out the minimisation step we introduce a genetic algorithm and discuss its tuning for maximal efficiency. [ABSTRACT FROM AUTHOR]

Smearing damage was created on cylindrical roller bearings (CRBs) using a laboratory test protocol that required alternating the load zone direction according to a square wave function. The experimental goal was to compare the wear protection afforded by various surface treatments, including vibratory superfinishing (ES20), black oxide treatment, and special tungsten carbide–reinforced amorphous hydrocarbon roller body coatings (WC/a-C:H). The only bearing treatments that did not smear in these severe tests were the WC/a-C:H bearings. Black oxide and ES20 bearings experienced smearing with the same frequency as untreated bearings, albeit to different degrees of microscopic damage. The test rig was instrumented to measure cage slip, which provided insight about the roller–raceway slip dynamics during the tests via kinematic calculations. The CAGEDYN bearing dynamics model was used to simulate the experimental smearing test conditions, and it provided encouragement that accurate prediction of smearing risk may be possible in the future with further development. [ABSTRACT FROM AUTHOR]

Reservoir simulation is an approach of recreating the occurring phenomena of the reservoir by solving the general governing equations that describe the reservoir processes. Finite difference technique is an effective method to get the solution out of the reservoir models for different scenarios. In light of many benefits of using course grid models rather than fine grid and simplification, using the same relative permeability curves from laboratory cannot be applied in the fields having large grid dimensions because of numerical dispersion (smearing) of finite difference modeling. Thus, the relative permeability curves must be modified based on the grid size and then applied into the simulator. The authors introduce a methodology to demonstrate how the lab relative permeability curves can be modified based on coarse grid sizes to honor the same anticipated rock behavior. Thus, an objective function is developed to minimize the numerical dispersion in a synthetic tilted reservoir by automatically changing the relative permeability and comparing the results with the equivalent fine model. By this method, modified relative permeability curves can be obtained and introduced to the coarse model. This modification workflow is almost inevitable for reservoir simulation models with very coarse grids and it eases the history-matching process by approaching more realistic solution. [ABSTRACT FROM PUBLISHER]

Newly developed self-lubricating Fe-Cr-C-Mn-Cu cast composite alloys were investigated to study the role of Cu-rich second phase particles which smear on the wear surface during sliding. The wear resistance of the material was improved with an increasing copper concentration. The improved wear resistance was probably obtained by forming a protective tribofilm, which prevented metal-to-metal contact through smearing of the embedded Cu-rich second phase particles. This formation of protective oxide films during sliding is likely to improve the wear resistance of austenitic Fe-Cr-C-Mn-Cu cast composite alloys. [ABSTRACT FROM AUTHOR]

Abstract: The dependence of the overlap Dirac operator on the Wilson-mass regulator parameter is studied through calculations of the overlap topological charge densities at a variety of Wilson-mass values, using a Lüscher–Weisz gauge action. In this formulation, the Wilson-mass is used in the negative mass region and acts as a regulator governing the scale at which the Dirac operator is sensitive to topological aspects of the gauge field. We observe a clear dependence on the value of the Wilson-mass and demonstrate how these values can be calibrated against a finite number of stout-link smearing sweeps. The overlap topological charge density is also computed using a pre-smeared gauge field for the input kernel. We show how applying the overlap operator leads to further filtering of the gauge field. The results suggest that the freedom typically associated with smearing algorithms, through the variable number of sweeps, also exists in the overlap operator, through the variable Wilson-mass parameter. [Copyright &y& Elsevier]

Two different characterizations of POV measures with commutative range are compared using a representation of some stochastic operators by (weak) Markov kernels. A representation by Choquet theorem is obtained as an integral over functions of a sharp observable appearing in one of the characterizations. A Naimark extension is constructed. [ABSTRACT FROM AUTHOR]

Purpose: To study the impact of selecting different data sets from four-dimensional computed tomography (4D CT) imaging during proton treatment planning in patients with distal esophageal cancer. Methods and Materials: We examined the effects of changes in 4D CT data set and smearing margins in proton treatment planning for 5 patients with distal esophageal cancer whose diaphragms were in the beam path and could move several centimeters during respiration. Planning strategies based on (1) average, (2) inspiration, and (3) expiration CT were evaluated in terms of their coverage on the internal clinic target volume (ICTV) at the prescribed dose. Results: For Strategy 1, increasing the smearing margin caused an increase in the ICTV prescription dose coverage (PDC) at the end-exhalation phase for all patients, whereas the ICTV PDC decreased for some patients at the end-inhalation phase. For Strategy 2, a smearing margin in the range of 1.0 to 3.5 cm caused the ICTV PDC to remain essentially unchanged, regardless of which phase of 4D CT was used for dose calculation, for all patients. For Strategy 3, the ICTV coverage was adequate for 2 of the 5 patients when a smearing margin of less than 1.0 cm was used, but was not adequate for the other 3 patients regardless of the smearing margin. Conclusion: Using the inspiration CT plus a smearing margin can lead to adequate ICTV coverage in treatment plans for patients with distal esophageal tumors surrounded by tissue that is subject to large changes in density during a proton treatment. [Copyright &y& Elsevier]

In this article, the mechanism of material removal (MR) in Abrasive Flow Machining (AFM) process has been studied. Representative components of pure Aluminum and Brass were processed by AFM under similar process conditions. The processed surfaces were analyzed with the help of Scanning Electron Microscopy (SEM). SEM photographs reveal noticeable difference between abrasion patterns produced on the processed surfaces of both the materials. A mechanism of MR has been proposed by examining the nature of interaction between the flowing abrasive medium and target work surfaces of selected materials. [ABSTRACT FROM AUTHOR]