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Purpose: The Achilles tendon consists of three subtendons with the ability to slide relative to each other. As optimal intratendinous sliding is thought to reduce the overall stress in the tendon, alterations in sliding behavior could potentially play a role in the development of Achilles tendinopathy. The aims of this study were to investigate the difference in intratendinous sliding within the Achilles tendon during isometric contractions between asymptomatic controls and patients with Achilles tendinopathy and the effect of changing the horizontal foot position on intratendinous sliding in both groups. Methods: Twenty‐nine participants (13 Achilles tendinopathy and 16 controls) performed isometric plantarflexion contractions at 60% of their maximal voluntary contraction (MVC), in toes‐neutral, and at 30% MVC in toes‐neutral, toes‐in, and toes‐out positions during which ultrasound images were recorded. Intratendinous sliding was estimated as the superficial‐to‐middle and middle‐to‐deep relative displacement. Results: Patients with Achilles tendinopathy present lower intratendinous sliding than asymptomatic controls. Regarding the horizontal foot position in both groups, the toes‐out foot position resulted in increased sliding compared with both toes‐neutral and toes‐out foot position. Conclusion: We provided evidence that patients with Achilles tendinopathy show lower intratendinous sliding than asymptomatic controls. Since intratendinous sliding is a physiological feature of the Achilles tendon, the external foot position holds promise to increase sliding in patients with Achilles tendinopathy and promote healthy tendon behavior. Future research should investigate if implementing this external foot position in rehabilitation programs stimulates sliding within the Achilles tendon and improves clinical outcome. [ABSTRACT FROM AUTHOR]

The process flow for production of tinplate is usually comprising electroplating, reflowing, passivation, and oiling to form a multilayer structure with excellent comprehensive performance. There are some differences between the edge and center of tinplate due to the edge effect during electroplating and passivation. The microstructure and composition of the multilayer at the edge and center of tinplate were compared using scanning electron microscope (SEM), ultraviolet-visible spectrophotometer, electrochemical workstation, X-ray photoelectron spectroscope (XPS), and glow discharge spectroscope (GDS). The results showed that the various layers at the edge of tinplate was nonuniform in morphology and composition. As compared with the center of tinplate, the content of each component in the metallic tin layer, tin alloy layer, and passivate layer were higher at the edge, indicating that the tin coating at the edge of tinplate was oxidized more seriously. [ABSTRACT FROM AUTHOR]

Breakdown (BD) voltage is significant in high-voltage power electric machines. Currently, BD voltages are mainly predicted by the semi-empirical formula in strongly inhomogeneous electric fields. However, the equation could not be applied for electrodes with weakly inhomogeneous electric fields. In this paper, positive lightning impulse BD voltages are predicted in various sphere-to-plane air gaps using forms of machine learning such as support vector regression (SVR), Bayesian regression (BR) and multilayer perceptron (MLP). Unlike previous studies, a method is also proposed by introducing streamer propagation characteristics as new features and by removing electric field gradients as unnecessary features to find out how to reduce the feature dimension. The streamer propagation characteristics are suggested to reflect the possibility of a discharge process between electrodes. Predicted voltages from machine learning algorithms are compared with the experimental results and calculated voltages from the semi-empirical formula. Firstly, the predictions from each model agreed well with the datasets. New features were observed to be applied for machine learning algorithms and to be as important as known electrostatic features before discharge. Secondly, predicted BD voltages were more accurate than calculated voltages from the semi-empirical equation in strongly inhomogeneous electric fields. Predictions from each model also agreed well with the experimental results in weakly inhomogeneous electric fields. The prediction accuracy of SVR was better than those of BR and MLP. Machine learning algorithms were also shown to be applied for electrodes with a wide range of inhomogeneities, unlike a semi-empirical method. We expect that the suggested features and machine learning algorithms can be used for accurately calculating BD voltages. [ABSTRACT FROM AUTHOR]

Flow maldistribution at the inlet of a heat exchanger (HX) is a significant parameter that needs to be considered to judge the performance of the same. In this paper, four arrangements of three‐fluid cross‐flow heat exchanger (3FCFHX) with different flow conditions are considered as shown in Figure 1 in which is the performance of cross‐countercurrent and cross‐cocurrent arrangements for uniform and flow maldistribution at the inlet. In addition, the effect of different inlet fluid flow models on the HX performance are investigated numerically. Among the three fluids in these arrangements, the central fluid is considered to be the hot fluid. From the principles of conservation of energy, the governing equations for three fluids are generated and solved using the finite element method. Four different inlet fluid‐flow models are considered for the analysis. Performance is judged using hot fluid effectiveness and the number of transfer units for a different range of governing parameters. The effects of inlet flow maldistribution (IFM) are measured using degradation factors. The results show that the performance of cross‐cocurrent arrangement is found to be superior to the cross‐countercurrent arrangement. In addition, the IFM enhances thermal performance. Further, it is determined that the flow maldistribution at the inlet will enhance the hot fluid effectiveness by 4%–4.5% and 1.8%–2% in cross‐cocurrent and countercurrent arrangements, respectively. The results give a thorough insight into the significant concerns involved in the design of such HXs. Application of the finite element method proves the ease of determining the exit temperatures of the fluids in the HX. This approach is indeed time‐saving and gives insights when compared to the CFD approach. [ABSTRACT FROM AUTHOR]

The field of quantum resource theory (QRT) has emerged as an invaluable framework for the examination of small and strongly correlated quantum systems, surpassing the boundaries imposed by traditional statistical treatments. The fundamental objective of general QRTs is to characterize these systems by precisely quantifying the level of control attainable to an experimenter. In this review article, we refrain from providing an exhaustive summary of the extensive literature on QRT. Rather, our focus centers on a specific subliterature founded upon the theory of majorization. The primary aim is to augment our comprehension of genuine quantum phenomena manifested across diverse technological applications and incite investigations into novel resource theories encompassing multiple types of resources. Consequently, we emphasize the underlying similarities shared by various resources, including bipartite quantum entanglement, quantum coherence, and superposition, alongside informational, thermal, and generalized nonequilibrium resources. [ABSTRACT FROM AUTHOR]

In the work using the finite element method, a three-dimensional computer model of the processes of electrothermal treatment of an aluminium core of a power cable in an electric furnace and a thermostat was developed, and the patterns of changes in the temperature field in such a core were determined under different modes of implementation of the so-called "annealing" processes, that is, the restoration of the necessary electrical properties in it , in particular, an increase in specific electrical conductivity and plasticity. Calculations based on the developed mathematical model and the obtained regularities are consistent with the results of practical measurements of electrical conductivity and plasticity of experimental samples of aluminium cores of cables manufactured by YUZHCABLE WORKS, PJSC, Kharkiv. However, the analysis of the patterns of changes in the temperature field in the volume of aluminium cores of cables during their continuous electric heating to the required temperatures of both the outer and inner layers of the core wound on a spool showed that the difference in their temperatures can exceed 50 0С. Such nonuniformity of the temperature field of the core and long-term overheating of its outer layers leads to unacceptable losses of electricity and reduces the positive result of the processes of such heat treatment of the core, in particular, regarding the increase of its electrical conductivity. It is substantiated that in order to reduce the loss of electricity and the nonuniformity of the temperature field in the aluminium core, it is necessary to reduce the duration of electric heating of the aluminium core to the temperature of its upper layers, necessary for annealing, and then move the drum with such a core to a thermostat without electronic heating elements. In such a thermostat, the temperature of the outer layers will decrease, and the temperature of the inner layers will continue to increase. The work shows that after some time (≈ 60 min), the temperature distribution in the core will become almost uniform, and the total losses of electricity and the nonuniformity of the temperature field in the volume of the core will become smaller. Based on the results of the calculations, recommendations were developed for the selection of appropriate modes of heat treatment of aluminium cores wound on a spool, with acceptable energy consumption and overheating of the upper layers of the core.

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HPR1000 NPP is designed with Passive Containment Heat Removal System (PCS) following the technical route called active and passive combined concept. The installed PCS system will have effect on the thermal hydraulic (T-H) behavior in the containment, and the complex T-H environment will influence the heat removal and operating character of PCS system backwards. The main goal of this work is to evaluate the effectiveness of the PCS system of HPR1000 and analyse the complex T-H environment of HPR1000 when the PCS system is operating. The HPR1000 containment is modelled by the containment T-H code and the PCS system is modelled based on experiment results. Then, the severe accident sequence initiated by large break LOCA is calculated by an integrated computer code, which outputs mass and energy release sources from reactor coolant primary system as boundaries for the containment T-H code. The results show that HPR1000 PCS system has enough heat removal capability under selected severe accident, which could ensure the containment meet the design requirement. Also, the nonuniformity of temperature and gases in the containment will disappear when the mass and energy releases turn stable, and the operating of PCS system does not cause a huge effect on containment inhomogeneity.

In practice, it is important to assess the nonuniformity of the crankshaft speed in internal combustion engines. In such assessments, the sensitivity of the chosen criteria to the following factors is of particular interest: the spread of the maximum pressure; and the spread in the operational characteristics in successive working cycles. In the present work, the criteria and operational characteristics are calculated in idling. A unique relation between the deviations in successive working cycles and the nonuniformity of the crankshaft speed is only possible in idling [1]. The following criteria are considered: the variation in the increment in crankshaft speed over the cycle in a sequence of operational cycles; the variation of the maximum crankshaft speed (its amplitude); the variation of the set of maximum and minimum crankshaft speeds; and the relation between the real and kinematic nonuniformity of the crankshaft speed. [ABSTRACT FROM AUTHOR]

Breakdown (BD) voltage is significant in high-voltage power electric machines. Currently, BD voltages are mainly predicted by the semi-empirical formula in strongly inhomogeneous electric fields. However, the equation could not be applied for electrodes with weakly inhomogeneous electric fields. In this paper, positive lightning impulse BD voltages are predicted in various sphere-to-plane air gaps using forms of machine learning such as support vector regression (SVR), Bayesian regression (BR) and multilayer perceptron (MLP). Unlike previous studies, a method is also proposed by introducing streamer propagation characteristics as new features and by removing electric field gradients as unnecessary features to find out how to reduce the feature dimension. The streamer propagation characteristics are suggested to reflect the possibility of a discharge process between electrodes. Predicted voltages from machine learning algorithms are compared with the experimental results and calculated voltages from the semi-empirical formula. Firstly, the predictions from each model agreed well with the datasets. New features were observed to be applied for machine learning algorithms and to be as important as known electrostatic features before discharge. Secondly, predicted BD voltages were more accurate than calculated voltages from the semi-empirical equation in strongly inhomogeneous electric fields. Predictions from each model also agreed well with the experimental results in weakly inhomogeneous electric fields. The prediction accuracy of SVR was better than those of BR and MLP. Machine learning algorithms were also shown to be applied for electrodes with a wide range of inhomogeneities, unlike a semi-empirical method. We expect that the suggested features and machine learning algorithms can be used for accurately calculating BD voltages.

The nonuniformity of stress and strain analysis is an important consideration that describes the bond behavior between concrete and externally bonded fiber reinforced polymer (FRP) laminates. The interfacial stress transfer between FRP and concrete generates a longitudinal strain gradient in the longitudinal (or FRP fiber) direction. Most of the available studies in this area have focused on nonuniformity in the longitudinal direction. In this paper, the nonuniformity in the FRP width direction is investigated by studying the strain distribution using digital image correlation (DIC) full-field optical techniques. In the direction along the FRP width, there is an area in the middle that has consistent strain and stress, while the edge regions have strain and stress gradients. During the complete debonding process, the width of the central area is found to be insignificantly affected by the concrete strength but significantly affected by the FRP stiffness. The fracture characteristics below the central region are purely Mode II fracture. However, the complex curved cracks and high in-plane shear strains at the interface near the FRP edge regions show a mixed mode with Modes II and III. This boundary effect results in a significant difference in the bond–slip characteristics of FRP along the width direction. The maximum bond stress of the central region is higher than that of the edge region. However, for FRP with higher stiffness, the inhomogeneity of the stress distribution is weakened. Moreover, it is reasonable to find that calculating the sum of the bearing capacity of the single FRP strips along the width direction is close to the experimental bond strength. Based on the research findings in this study, it is qualitatively recommended that the width factor model in calculating FRP-concrete bond strength should include the significant effect of FRP stiffness. • The stress and deformation nonuniformities in the FRP width direction are initially investigated. • The width of the central stable portion increases with increasing FRP stiffness but is insensitive to the concrete strength. • By dividing the FRP into multiple strips with different bond–slip curves, the sum load matches well with the experimental peak load. • A new rational and accurate width factor model considering the FRP stiffness effect is necessary to be developed. [ABSTRACT FROM AUTHOR]

The spatial distribution of the emission intensity in the near field of a laser-diode bar with a wavelength of 808 nm is obtained experimentally. During the experiments, laser diodes operate in the quasi-continuous lasing mode in the range of injection currents from the threshold value to the onset of degradation of individual laser diodes. On the basis of analysis of the distribution of the emission intensity in the near field in the direction parallel to epitaxial layers, a system of parameters is proposed that makes it possible to obtain a probabilistic estimate of the limiting value of the injection current of individual diodes. During optical inspection of the surface of the laser diodes, it is found that the failure of individual diodes in most cases occurs due to catastrophic optical degradation of the semitransparent mirror of a laser cavity formed on the cleaved surface of a semiconductor. The proposed system of parameters includes both previously known and new ones: the ratio of the maximum and average values of the intensity of laser diodes in the spatial distribution, the standard deviation of the intensity, and a parameter that takes into account the emission intensity of edge-emitting laser diodes. As a result of analysis of the spatial distribution of the emission intensity in the near field of a laser-diode bar in the working section of the light–current characteristic, it is possible to single out individual laser diodes characterized by the lowest limiting injection current and to predict the development of degradation processes. [ABSTRACT FROM AUTHOR]

The study of [1] considers the effect on the sintering process caused by charge flow stabilization during charge loading operations in the sintering machines. This article presents the results of a study concerning the formation of a rational sinter charge layer profile, consisting in an equalization of the vertical sintering rate along the width of the sintering machines. By introducing this measure at the Magnitogorsk Iron & Steel Works (MMK) sinter plant No. 5, it was possible to achieve a 3.2–3.5% increase in the productivity of sintering machines. [ABSTRACT FROM AUTHOR]

The pre-swirl system is of great importance for temperature drop and cooling air supply. This study aims to investigate the influencing mechanism of heat transfer, nonuniform thermodynamic characteristics, and cooling air supply sensitivity in a pre-swirl system by the application of the flow control method of the pre-swirl nozzle. A novel test rig was proposed to actively control the supplied cooling air mass flow rate by three adjustable pre-swirl nozzles. Then, the transient problem of the pre-swirl system was numerically conducted by comparison with 60°, 120°, and 180° rotating disk cavity cases, which were verified with the experiment results. Results show that the partial nozzle closure will aggravate the fluctuation of air supply mass flow rate and temperature. When three parts of nozzles are closed evenly at 120° in the circumferential direction, the maximum value of the nonuniformity coefficient of air supply mass flow rate changes to 3.1% and that of temperature changes to 0.25%. When six parts of nozzles are closed evenly at 60° in the circumferential direction, the maximum nonuniformity coefficient of air supply mass flow rate changes to 1.4% and that of temperature changes to 0.20%. However, different partial nozzle closure modes have little effect on the average air supply parameters. Closing 14.3% of the nozzle area will reduce the air supply mass flow rate by 9.9% and the average air supply temperature by about 1 K. [ABSTRACT FROM AUTHOR]

Multiple identical paths are usually connected to form circulating loops in many industrial reactors including chemical looping combustion (CLC), however the flow pattern may be highly nonuniform in these identical paths, compromising the stable operation. In this study, by using the Eulerian multifluid model, the nonuniformity in a CLC apparatus is studied. First, the symmetry of computational domain is verified by simulation and the model setting is validated by experimental data. Then the typical nonuniformity phenomenon is discussed and evaluated in terms of bed inventory evolution and gas-solid distribution in symmetrical parts. The effects of key operating parameters including total bed inventory, gas aeration rate, and wall roughness on nonuniformity degree are then studied. The simulating results show that the nonuniformity degree between the two symmetrical parts increases with the increase of total bed inventory and gas aeration rate and this trend will be intensified in the predictable short-term future. And through the analysis of pressure fluctuation, the instability of the system is aggravated. However, wall roughness shows an indefinite influence and tendency. This work provides an insightful understanding of nonuniformity and will help further optimise symmetrical CLC systems. [Display omitted] • Nonuniformity in a symmetrical CLC unit is studied using Eulerian multifluid model. • Nonuniformity of gas-solid distribution is observed in a symmetrical CLC model. • Enlarging total bed inventory and gas aeration rate can enhance nonuniformity. • Specularity coefficient has an insignificant influence on the degree of nonuniformity. [ABSTRACT FROM AUTHOR]

Photo response nonuniformity (PRNU) is a crucial parameter in evaluating and choosing CMOS image sensors. The current methods and standards use the integrating sphere to illuminate the sensor and assume a known uniform illumination. And PRNU is calculated based on the spatial variance of images. In practice, the uniformity of illuminance can be hardly guaranteed. A slight nonuniformity will cause a significant increase in spatial variance and bring unacceptable evaluation errors. In this article, we present a novel method to estimate PRNU of linear CMOS image sensors. The method allows nonuniform illumination and does not require specific settings for the light source and sensors. First, an observation model is established for the data of nonuniformly exposed images. The model is composed of an irradiance model and a noise model. The irradiance model describes the original output, and the noise model depicts the noise variance as a function of local illuminance. PRNU is a parameter in the noise model to be estimated. Then, the model parameters including PRNU are estimated by a two-stage method based on maximum likelihood estimation. We also use simulations to validate the developed methods and demonstrate the robustness of the model under sensor misalignment. Finally, the proposed method is illustrated by a measurement experiment. [ABSTRACT FROM AUTHOR]

Various methods of attaching stepped thin-walled cylinders in honing are considered. Means of increasing the machining precision of the hole are proposed. In the analysis, the nonuniform deformation of the cylinder by the clamping forces is taken into account, and radial forces simulate the cutting forces. The stress–strain state is determined by the finite-element method using DEFORM-3D (v. 6.1) software. [ABSTRACT FROM AUTHOR]

• Soiling particle diameters vary from ∼1 μm to ∼100 μm. • Average power deterioration of ∼6–7% per 5% drop in transmittance. • Nonuniform soiling leads to a 13% transmittance drop and a 2 °C temperature rise. • Nonuniform soiling reduces power generation by up to ∼30 % relative to a clean module. • Nonuniform soiling leads to hotspot formation and a 7% spatial power output variation. Photovoltaic (PV) module soiling, i.e., the accumulation of dust on PV module surfaces, poses several challenges to PV system performance. Among these challenges, the nonuniform deposition of soiling across the module surface has received scarce attention. Soiling is directly associated with an overall performance loss, but can also potentially give rise to localised hotspots that can lead to long-term PV module failure. Therefore, addressing the issues arising from this nonuniformity is not only important for optimising energy production, but also for enhancing system reliability, and ensuring the long-term operation of relevant power generation systems. In this study, the impact of nonuniform soiling on PV performance is investigated experimentally by examining soil deposition on the upper surfaces of low-iron glass samples. Samples positioned at four different tilt angles were collected on a monthly basis over a one-year study period. Since the horizontal samples were found to represent the worst-case conditions, the most soiled sample at horizontal tilt was divided into four zones, each housing a single monocrystalline solar cell and examined further. The findings reveal that the soiled sample experiences an average transmittance deterioration of 13% relative to a clean sample, and a maximum (relative) spatial variation of 4% between the four zones. These optical losses affect the amount of sunlight received by the cells, resulting in a power deterioration of ∼6–7% per 5% drop in transmittance. The soiled sample experienced an average temperature rise of 2 °C, and an average power output (and efficiency) reduction of 30% relative to the clean sample, and a maximum (relative) spatial variation of 7% between the zones. The 30% average power loss measured in this nonuniform soiling case is more than double that which would be expected theoretically for a transmittance loss of 13% but from uniform soiling, so these results highlight the importance of addressing PV soiling for optimal PV performance, and of accounting for spatial soiling nonuniformity. [ABSTRACT FROM AUTHOR]

Improving the quantification of the transverse mixing coefficient in rivers is essential for a better estimation of pollutant dispersion. This coefficient is evaluated from tracing experiments or from semi‐empirical equations assuming uniform flow conditions. This assumption, verified for laboratory experiments, is questionable for river studies. For example, piedmont rivers exhibit nonuniform flows due to their longitudinal morphological variations. This work aims at studying the longitudinal variability of the transverse mixing coefficient in a river with longitudinally varied morphology and the overlooked impact of the flow nonuniformity on the coefficient's values. Tracing experiments were conducted in the Durance River in France using slug injections and concentration measurements made at the cross‐sections delineating homogeneous sub‐reaches. Using the well‐known 1D transverse diffusion model, values of the transverse mixing coefficient are determined for all consecutive sub‐reaches. These values substantially vary along the studied river, with stronger mixing efficiency at pools and complex riffles and weaker mixing efficiency in straight sub‐reaches with emerging obstacles. The dimensionless transverse mixing coefficient is strongly related to a parameter quantifying the deviation from flow‐uniformity, i.e., indicating flow acceleration, deceleration or a succession of both within the sub‐reaches. While usual formulas from the literature fail to predict our empirical results, a new equation including the flow nonuniformity parameter fits our experimental data with high accuracy. After further validation, such equation may be used for predicting the transverse mixing coefficient in rivers with longitudinally varied morphology. Key Points: Tracing experiments in a shallow, gravel‐bedded river yield highly variable transverse mixing coefficientsUsual predictive formulas fail to predict reach‐averaged transverse mixing coefficients in a river with longitudinally varied morphologyAn equation based on a flow nonuniformity parameter is fitted to our experimental data [ABSTRACT FROM AUTHOR]

Purpose: The Achilles tendon consists of three subtendons with the ability to slide relative to each other. As optimal intratendinous sliding is thought to reduce the overall stress in the tendon, alterations in sliding behavior could potentially play a role in the development of Achilles tendinopathy. The aims of this study were to investigate the difference in intratendinous sliding within the Achilles tendon during isometric contractions between asymptomatic controls and patients with Achilles tendinopathy and the effect of changing the horizontal foot position on intratendinous sliding in both groups., Methods: Twenty-nine participants (13 Achilles tendinopathy and 16 controls) performed isometric plantarflexion contractions at 60% of their maximal voluntary contraction (MVC), in toes-neutral, and at 30% MVC in toes-neutral, toes-in, and toes-out positions during which ultrasound images were recorded. Intratendinous sliding was estimated as the superficial-to-middle and middle-to-deep relative displacement., Results: Patients with Achilles tendinopathy present lower intratendinous sliding than asymptomatic controls. Regarding the horizontal foot position in both groups, the toes-out foot position resulted in increased sliding compared with both toes-neutral and toes-out foot position., Conclusion: We provided evidence that patients with Achilles tendinopathy show lower intratendinous sliding than asymptomatic controls. Since intratendinous sliding is a physiological feature of the Achilles tendon, the external foot position holds promise to increase sliding in patients with Achilles tendinopathy and promote healthy tendon behavior. Future research should investigate if implementing this external foot position in rehabilitation programs stimulates sliding within the Achilles tendon and improves clinical outcome., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The article discusses the results of soil and geobotanical studies at the plots on the coastal plain of the Caspian Sea (Northern Dagestan) of different ages: 1340 ± 36 years calBP (Kaspii-1) and 293 ± 13 years calBP (Kaspii-2). Changes in the biodiversity of the vegetation cover and the soil-salinity variation over time are assessed. It is shown that the variability of soil salinity (range, quartile scale, and standard deviation) at the local level (areas of nonuniformity with linear dimensions of meters or tens of meters) has increased, while the parameters of vegetation biodiversity (floristic richness, the species number, the family number, the number of long-vegetating herbaceous perennials and ephemers, the presence of species with different salinity tolerance, and differentiation of the intracoenotic diversity) have decreased. The plot with a Tamarisk community (Kaspii-2) is characterized by a statistically significant, moderate correlation (R2 = 0.29) between soil salinity and vegetation based on data on the distribution of dominant species, whereas this correlation is not significant on the older plot with a saltwort-suaeda community (Kaspii-1). The data show that, when the area dries up after sea regression, the variation in soil properties (salinity) and vegetation changes in different directions: the variation in soil salinity (functional pedodiversity) increases with age, while the variation in vegetation (phytodiversity) decreases. Moisture availability is obviously the main factor limiting the biodiversity on the older plot on the background of high salinization of soils on the both plots as evidenced with the smaller moisture reserve in the top 1-m soil layer on the older plot. [ABSTRACT FROM AUTHOR]

In the automotive turbochargers centrifugal compressor, the volute has a strong potential effect, leading to circumferential nonuniformity of the impeller flow field and compressor stall. In this study, full-annulus unsteady simulations for centrifugal compressors with vaned/vaneless diffusers are carried out. The influence of the diffuser vane on the potential effect of the volute and stall behavior of a centrifugal compressor is studied in detail. Based on the distribution of the casing static pressure, the formation mechanism of the circumferential distribution of static pressure and the reverse propagation process of pressure waves caused by pressure distortion are revealed. The results of this study show that the diffuser vanes can weaken the potential effect of the volute on the impeller flow field by reducing the degree of static pressure distortion. The number of static pressure peaks in the circumferential direction is related to the number of vanes/blades. The diffuser vanes can change the circumferential position of the stall inception, but cannot eliminate the "locking effect" of the volute tongue on the circumferential position of the stall. In other words, the circumferential position of the stall inception is still determined by the volute tongue for a centrifugal compressor with a vaned diffuser. Although the degree of circumferential static pressure distortion inside the impeller is reduced, the stable operating range of the compressor cannot be significantly widened by adjusting the stagger angle of the diffuser vane when the stall first occurs at the impeller inlet. [ABSTRACT FROM AUTHOR]

Featured Application: The work uses a patch-based inpainting method that is capable of filling the missing areas or removing unwanted objects in a digital image. Patch-based image inpainting methods iteratively fill the missing region via searching the best sample patch from the source region. However, most of the existing approaches basically use the fixed size of patch regardless of content features nearby, which may lead to inpainting defects. Also, global match is needed for searching the best sample patch, but only to fill one target patch in each iteration, resulting in low efficiency. To handle the issues above, we first evaluate the nonuniformity in an image, by which the patch size is adaptively determined. Moreover, we divide the source region into multiple non-overlapping subregions with different nonuniformity levels, and the patch match proceeds in every subregion, respectively. This strategy not only saves the match time for single target patch, but also reduces the mismatch, and enables the simultaneous filling of multiple target patches in a single iteration. Experimental results show that in comparison to previous patch-based works, our method has achieved further improvement both in quality and efficiency. We believe our method could provide a new way for patch match with better accuracy and efficiency in image inpainting tasks. [ABSTRACT FROM AUTHOR]

Infrared focal plane array is affected by nonuniformity, which leads to the generation of infrared image blind pixels and reduces the image quality. This paper puts forward an infrared blind-pixel compensation algorithm based on generative adversarial networks and Poisson image blending (GAN–PIB), which implements the greyscale prediction of the original image blind pixels through the combination of the pre-trained adversarial network and the blind-pixel compensation function and in the form of generating new images, breaking through the traditional thinking of the existing compensation algorithm based on interpolation and filtering. Firstly, the blind-pixel compensation network is constructed based on the generative adversarial networks. Through training, the model learns the image features of infrared blind pixels and achieves a better compensation effect for the blind-pixel image data sets which are used for training. Secondly, the blind-pixel detection of the test blind-pixel images is carried out to generate a binary mask matrix, and the constructed blind-pixel compensation loss function is combined to create the fake image. Finally, by fitting the original blind-pixel image and the generated image with the Poisson image blending algorithm, the compensation precision is improved through iteration, and finally, the compensation for the infrared blind pixels is completed. The experimental results show that GAN–PIB algorithm has strong adaptability to isolated blind pixels and clustered blind pixels, and compared with traditional algorithms, the compensated images have higher intelligibility and texture details. [ABSTRACT FROM AUTHOR]

Nonuniform performance of the parallel channels of the microchannel heat sink is one of the major limitations aggravating many undesired influences in both the single phase and the two phase heat transfer in microchannel heat sink. The nonuniform performance of the channels is preliminarily governed by the nonuniformity of the mass flow rate and heat flux transferred from the interface of parallel microchannels. The poor heat transfer (adiabatic/natural convection) boundary condition is primarily responsible for heat flux nonuniformity. In the current study a novel design of parallel microchannels heat sink is proposed, which is obtained by decreasing nonuniformity of mass flow rate and heat transfer existing between parallel channels of the microchannel heat sink. The nonuniformity of the mass flow rate is removed by the existing variable width approach and heat transfer nonuniformity among parallel channels is solved by the newly developed slanted microchannel provision. Developed design normalizes flow nonuniformity by 95.5% and heat transfer nonuniformity by 97.5% in comparison to the conventional design microchannel heat sink. The two major benefits offered by the proposed design are cooled (4.2 K lower than the conventional design) and uniform (3.1 K lesser than the conventional design) base surface temperature. It is also found that proposed work even facilitated in reduction of average base temperature (1.3 K lower than the conventional design). The maximum improvement in Nusselt number is 4.07%, also the proposed design extends benefits at off-design conditions even. [ABSTRACT FROM AUTHOR]

In this paper, the impingement cooling performance on pin-fin heat sinks is experimentally and numerically investigated with different outlet arrangements and pin-fin layouts. Compared with one-way opening arrangement, results show that the two-way opening arrangement can offer a much lower pressure loss ($\Delta p$) due to shorter flow distance of airflow from outer jets. Meanwhile, it is surprising that the two-way opening arrangement still offers appreciable improvements on effective heat transfer coefficient ($h_{\mathrm {eff}}$). This is because the fountain may shift toward the outer jets more rapidly with one-way opening arrangement. Yet the implementation of staggered pin-fin layout has minor improvement on $h_{\mathrm {eff}}$. However, $\Delta p$ can be obviously reduced by 11.1% due to the more effective spreading of impinging airflow in radial direction. The $h_{\mathrm {eff}}$ value can be further increased by 8.8% when a smaller jet-to-target distance is applied. With priority consideration of hot spots in electronic cooling, the nonuniformity of local Nusselt number (${S}$) is further studied through the computational fluid dynamics (CFD) method. ${S}$ approaches 18.5% when the airflow directly impinges on a flat surface with optimized jet array. Implementing pin-fin heat sinks can reduce the nonuniformity of Nusselt number distribution to fall below 8.0%. The nonuniformity of local Nusselt number can be further reduced to 1.8% by applying four-way opening arrangement and larger central jet at the same time. [ABSTRACT FROM AUTHOR]

The results of kinematic analysis of the ASz-62IR radial engine crankshaft was presented. In addition, the one-dimensional model of the working cycle of the engine was created in AVL BOOST system. Differences in the waveforms for each pistons causes the differences in the filling process what reflects in the mass of the load supplied to cylinders. Additionally, due to one dimensional model computation. The results show differences in the value of maximum pressure. This causes differences in mean effective pressure of up to 4% and which also affects the vibrations of the whole engine.

The uniformity degree of the air distribution over the heat-exchange surface of an air cooled condenser (ACC) plays an important role since it determines the efficiency of this surface's usage. In this paper, this factor at a special stand, where all the main processes of an air flow were simulated, is studied. The typical design of the A-framed ACC was chosen as the basis for the study. Two ACC models differing from one another by the presence of a diffuser after the fan were studied. Each of the models was tested in two versions: with a low-speed electric motor and a high-speed electric motor with a gearbox. In the ACC models, heat transfer surfaces were simulated by a set of flat metal grids with a uniform distribution of square cells. The aerodynamic drag of a set of grids was preliminarily selected so that the Euler criteria were equal for the full-scale object and model. During the tests, the air velocities in front of and behind the grids were measured by traversing, and the velocity fields (isotachs) of the cooling air in these sections were plotted. A condenser with a low-speed electric motor provides the most uniform distribution of cooling air over the heat-exchange surface, while condensers with a high-speed electric motor and gearbox and with a diffuser have significantly greater nonuniformity in the air supply. During the "suction" operation, the flow distribution is more uniform but worse than that for the version with a low-speed electric motor. The effect of the nonuniform velocity field of cooling air on the heat transfer of ACC is estimated. The real condenser module was calculated for various flow and velocity distributions along the tube length. Losses of heat removal due to the nonuniformity of the air flow of the considered circuits can be estimated within 1–3% at a ±50% deviation of the flow rate from the average value. [ABSTRACT FROM AUTHOR]

Device dimension scaling and process complexity have revealed new phenomena such as post-breakdown (BD) and variability issues in advanced technology nodes. Coupling of the first BD phenomena and their methodologies discussed in part I with the development of post-BD methodologies allows engineers to use device stress-data to accurately predict the product failure lifetime. The statistical modeling and new advances in understanding the root cause of variability issues have mitigated these seemingly uncontrollable “catastrophes” so that the scaling of the advanced technology process can continue its successful path forward. These two important aspects of dielectric BD will be reviewed in part II. [ABSTRACT FROM AUTHOR]

For a centrifugal compressor with volute, the flow field is circumferentially nonuniform because of the volute asymmetrical structure and leads to a circumferential difference in the tip leakage flow. In this work, the compressor performance and the casing wall static pressure distribution are measured, and the results are compared with the time-averaged results of the unsteady calculation to verify the reliability of the simulation. The results show a relationship between the tip leakage vortex trajectory and the high static pressure region in the diffuser, based on which a prediction model is established for the reverse propagation of pressure waves caused by a volute tongue. Influenced by the volute asymmetric structure, the trajectory, shape, and strength of the tip leakage vortex at different circumferential positions differs significantly. The tip leakage vortex trajectory affected by the high static pressure is more inclined to a circumferential direction because the tip leakage flow velocity flowing out of the suction surface is reduced, and the tip leakage flow with low velocity is subjected to the high-pressure gradient in a passage. Moreover, the tip leakage vortex breakdown in different passages differs significantly. A tip leakage vortex core more inclined towards the streamwise direction is more likely to break down than a tip leakage vortex core inclined towards the circumferential direction because of the larger reverse pressure gradient. [ABSTRACT FROM AUTHOR]

For most large-area applications, spatial nonuniformity of transistor characteristics makes it difficult if not impossible, to achieve adequate performance. Nonuniform parameters may lead to variations in color or gray level, which is commercially not viable. A variation in threshold voltage, mobility or ${I}-{V}$ characteristics of an organic thin-film transistor (OTFT) in a pixel circuit can result in unacceptable variation in the current driving the organic light-emitting diode (OLED) which accounts for large nonuniformities in the pixel brightness. Given its importance, a fast and straightforward method for characterization of device variations would be of great help in the process development and optimization. In the present work, a simple, easy to fabricate two-terminal asymmetric metal–insulator–semiconductor (AMIS) capacitive test structure is proposed for quick and accurate characterization of the process-induced nonuniformities in mobility, threshold voltage, and drain current. The capacitance–voltage (${C}-{V}$) characteristic of the proposed AMIS structure is derived mostly from the channel, and its contribution to the total capacitance at any given frequency depends on channel properties including mobility and threshold voltage. At low frequencies, the ${C}-{V}$ characteristics become independent of the series resistances, and hence, complex techniques can be sidestepped for accurate estimation of channel properties. The simulation results are presented to demonstrate the concept using a single AMIS test structure. The experimental results obtained with top contact pentacene based on AMIS arrays are presented to show the concept and advantages of the proposed structure. [ABSTRACT FROM AUTHOR]

The emerging graphene foams (GrFs) have received increasing attention in both scientific and engineering fields in recent years. A good elasticity is the prerequisite for its further applications. However, the mechanism and basic characteristics of elasticity of GrFs have not been understood clearly so far. In this paper, we conduct systematic simulations of compression-uncompression and tension-untension to study the characteristics of GrF elasticity using the coarse-grained molecular dynamics (CGMD) method. We find that deformation of GrFs is highly nonuniform at the scale of both flakes and regions, which is qualitatively consistent with the experimental observations. The deformation of GrFs is dominated by the flake bending rather than stretching, which is independent of the loading type, size, shape or thickness of flakes, as well as the density or stiffness of crosslinks. The great asymmetry of elasticity under tension and compression is induced by different mode of bond breaking. Furthermore, by evaluating the elastic energy density, we find that both thicker flakes and more crosslinks are two key factors responsible for good elasticity of GrFs. These results should be useful for understanding GrF elasticity and further design of advanced graphene-based materials. Image 1 [ABSTRACT FROM AUTHOR]

Evaluating the joint significance of covariates is of fundamental importance in a wide range of applications. To this end, p-values are frequently employed and produced by algorithms that are powered by classical large-sample asymptotic theory. It is well known that the conventional p-values in Gaussian linear model are valid even when the dimensionality is a non-vanishing fraction of the sample size, but can break down when the design matrix becomes singular in higher dimensions or when the error distribution deviates from Gaussianity. A natural question is when the conventional p-values in generalized linear models become invalid in diverging dimensions. We establish that such a breakdown can occur early in nonlinear models. Our theoretical characterizations are confirmed by simulation studies. [ABSTRACT FROM AUTHOR]

Contact problem for a system of rigid rough punches and layered foundation with nonuniform upper layer is considered.Mathematical model of the problem is compiled. It's effective solution is constructed by using Manzhirov projection method. Qualitative conclusions are presented. [ABSTRACT FROM AUTHOR]

Mild steel was successfully joined by linear friction welding. Grain size at peripheral region was coarser than that at the other zones of the weld interface, which had no significant effect on microhardness. The local tensile properties were considerably decreased when oxides or lack of bonding appeared at the interface. Ductile fracture dominated the fracture mode for all joints. Variation in local tensile properties could be relieved under a medium friction pressure, a relatively high amplitude with a sufficient friction time. It was attributed to the facts that plastic metal layer of joint became uniform to some extent and interfacial defects were eliminated. The standard deviation of plastic metal layer thickness (χp) could be used to describe the combined effects of welding parameters on joint integral performance. It was found that the standard deviation of plastic metal layer thickness showed a strong inverse correlation with the joint integral performance. Well-formed and defect-free joints exhibiting 90% of the base metal tensile strength could be produced when processing at a frequency of 20 Hz with a friction pressure of 103 MPa or 155 MPa, an amplitude of 2.5 mm and a friction time of at least 4 s. [ABSTRACT FROM AUTHOR]

• (1) A unified phase diagram is proposed that exhibits the relationship of the water depths from downstream to upstream of an emergent canopy. • (2) The threshold for identifying strong or weak nonuniformity is explored based on the relative backwater rise in the vegetated flow. • (3) The backwater rise of an emergent canopy is predicted from a dimensionless vegetated parameter and unit discharge based on the momentum loss. • (4) The effect of downstream water depth on backwater rise is quantified by two partitions: supercritical flow and subcritical flow. Vegetation is widely used to restore waterways and wetland ecosystems. However, emergent canopies create a nonuniform water surface, and predicting the backwater rise is necessary to evaluate the flood hazard. This paper investigates the water surface elevation from downstream to upstream of an emergent canopy in a steady nonuniform flow and predicts the upstream backwater rise. Laboratory flume experiments are conducted on rigid vegetation with varying coverage exposed to different flow rates. The backwater rise and the nonuniformity of vegetated flow are explored based on a momentum equation, and a general formula for backwater rise within and downstream of an emergent canopy is proposed for nonuniform flow. The results reveal that a unified phase diagram of backwater rise can be derived from the momentum model, which presents the variation of both the upstream and downstream water surface elevations and acquires a threshold to identify strong or weak nonuniformity in vegetated flow. The upstream water depth H 1 exhibits a nonmonotonic variation, first decreasing and then increasing with water depth H 2 at the trailing edge of the emergent canopy. Two partitions of subcritical flow and supercritical flow for the downstream water depth H 3 are quantified by the experimental data. The proposed model can be used to accurately predict the backwater rise based on a dimensionless vegetated parameter C veg and unit discharge q , as demonstrated by both the present and previous experimental results. This work improves the understanding and predictability of the nonuniformity and backwater rise generated by emergent canopies in natural or ecology-restored rivers. [ABSTRACT FROM AUTHOR]

Patch-based image inpainting methods iteratively fill the missing region via searching the best sample patch from the source region. However, most of the existing approaches basically use the fixed size of patch regardless of content features nearby, which may lead to inpainting defects. Also, global match is needed for searching the best sample patch, but only to fill one target patch in each iteration, resulting in low efficiency. To handle the issues above, we first evaluate the nonuniformity in an image, by which the patch size is adaptively determined. Moreover, we divide the source region into multiple non-overlapping subregions with different nonuniformity levels, and the patch match proceeds in every subregion, respectively. This strategy not only saves the match time for single target patch, but also reduces the mismatch, and enables the simultaneous filling of multiple target patches in a single iteration. Experimental results show that in comparison to previous patch-based works, our method has achieved further improvement both in quality and efficiency. We believe our method could provide a new way for patch match with better accuracy and efficiency in image inpainting tasks.