Статті в журналах з теми "Weak local residuals"
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Mungkasi, Sudi, and Stephen Gwyn Roberts. "Weak Local Residuals as Smoothness Indicators in Adaptive Mesh Methods for Shallow Water Flows." Symmetry 12, no. 3 (March 1, 2020): 345. http://dx.doi.org/10.3390/sym12030345.
Повний текст джерелаАнотація:
This paper proposes some formulations of weak local residuals of shallow-water-type equations, namely, one-, one-and-a-half-, and two-dimensional shallow water equations. Smooth parts of numerical solutions have small absolute values of weak local residuals. Rougher parts of numerical solutions have larger absolute values of weak local residuals. This behaviour enables the weak local residuals to detect parts of numerical solutions which are smooth and rough (non-smooth). Weak local residuals that we formulate are implemented successfully as refinement or coarsening indicators for adaptive mesh finite volume methods used to solve shallow water equations.
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Mungkasi, Sudi, Zhenquan Li, and Stephen Gwyn Roberts. "Weak local residuals as smoothness indicators for the shallow water equations." Applied Mathematics Letters 30 (April 2014): 51–55. http://dx.doi.org/10.1016/j.aml.2013.12.007.
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Roberts, Stephen Gwyn, and Sudi Mungkasi. "Well-balanced computations of weak local residuals for the shallow water equations." ANZIAM Journal 55 (December 9, 2015): 128. http://dx.doi.org/10.21914/anziamj.v56i0.9369.
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Jia, Zhuo, Sixin Liu, Ling Zhang, Bin Hu, and Jianmin Zhang. "Weak Signal Extraction from Lunar Penetrating Radar Channel 1 Data Based on Local Correlation." Electronics 8, no. 5 (May 23, 2019): 573. http://dx.doi.org/10.3390/electronics8050573.
Повний текст джерелаАнотація:
Knowledge of the subsurface structure not only provides useful information on lunar geology, but it also can quantify the potential lunar resources for human beings. The dual-frequency lunar penetrating radar (LPR) aboard the Yutu rover offers a Special opportunity to understand the subsurface structure to a depth of several hundreds of meters using a low-frequency channel (channel 1), as well as layer near-surface stratigraphic structure of the regolith using high-frequency observations (channel 2). The channel 1 data of the LPR has a very low signal-to-noise ratio. However, the extraction of weak signals from the data represents a problem worth exploring. In this article, we propose a weak signal extraction method in view of local correlation to analyze the LPR CH-1 data, to facilitate a study of the lunar regolith structure. First, we build a pre-processing workflow to increase the signal-to-noise ratio (SNR). Second, we apply the K-L transform to separate the horizontal signal and then use the seislet transform (ST) to reserve the continuous signal. Then, the local correlation map is calculated using the two denoising results and a time–space dependent weighting operator is constructed to suppress the noise residuals. The weak signal after noise suppression may provide a new reference for subsequent data interpretation. Finally, in combination with the regional geology and previous research, we provide some speculative interpretations of the LPR CH-1 data.
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Alcantara, C. A., J. D. Escoto, A. C. Blanco, A. B. Baloloy, J. A. Santos, and R. R. Sta. Ana. "GEOSPATIAL ASSESSMENT AND MODELING OF URBAN HEAT ISLANDS IN QUEZON CITY, PHILIPPINES USING OLS AND GEOGRAPHICALLY WEIGHTED REGRESSION." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W16 (October 1, 2019): 85–92. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w16-85-2019.
Повний текст джерелаАнотація:
Abstract. Urbanization has played an important part in the development of the society, yet it is accompanied by environmental concerns including the increase of local temperature compared to its immediate surroundings. The latter is known as Urban Heat Islands (UHI). This research aims to model UHI in Quezon City based on Land Surface Temperature (LST) estimated from Landsat 8 data. Geospatial processing and analyses were performed using Google Earth Engine, ArcGIS, GeoDa, and SAGA GIS. Based on Urban Thermal Field Variance Index (UTFVI) and the normalized mean per barangay (village), areas with strong UHI intensities were mapped and characterized. high intensity UHIs are observed mostly in areas with high Normalized Difference Built-up Index (NDBI) like the residential regions while the weak intensity UHIs are noticed in areas with high Normalized Difference Vegetation Index (NDVI) near the La Mesa Reservoir. In the OLS regression model, around 69% of LST variability is explained by Surface Albedo (SA), Sky View Factor (SVF), Surface Area to Volume Ratio (SVR), Solar Radiation (SR), NDBI and NDVI. OLS yield relatively high residuals (RMSE = 1.67) and the residuals are not normally distributed. Since LST is non-stationary, Geographically Weighted Regression (GWR) regression was conducted, proving normally and randomly distributed residuals (average RMSE = 0.26).
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Mircheva, Biliana, Milen Tsekov, Ulrich Meyer, and Guergana Guerova. "Analysis of the 2014 Wet Extreme in Bulgaria: Anomalies of Temperature, Precipitation and Terrestrial Water Storage." Hydrology 7, no. 3 (September 9, 2020): 66. http://dx.doi.org/10.3390/hydrology7030066.
Повний текст джерелаАнотація:
Impact on the hydrology cycle is projected to be one of the most noticeable consequences of climate change. An increase in regional dry and wet extremes has already been observed, resulting in large socioeconomic losses. The 2014 wet conditions in Bulgaria present a valuable case study for analyzing the interaction between multiple drivers that are essential for early forecasting and warning of flood events. In this paper, time series analysis of temperature, precipitation and Terrestrial Water Storage Anomaly (TWSA) is performed and cross-correlations between observations and climate variability indices are computed for a 12-year period. In Bulgaria, a positive linear temperature trend was found with precipitation and TWSA exhibiting negative trends for the period 2003–2014. The year 2014 started with a drier and warmer than usual winter followed by five consecutive wet months from March to July. We found the following long-term variations: (1) temperature showing a local minimum in November 2014, (2) precipitation peaks in July 2014 and (3) a local TWSA maximum in December 2014. Over a 12-year period, weak to moderate negative correlations were observed between the long-term components of temperature, precipitation and TWSA. Moderate positive correlations with a 3 to 6-month lag were obtained between precipitation and TWSA long-term components. The long-term trends of temperature and precipitation from surface observations and atmospheric reanalysis showed very good alignment. Very large subseasonal precipitation residuals from observations and atmospheric reanalysis were obtained for April and September 2014. Two oscillation indices showed: (1) weak correlations with precipitation and (2) weak to moderate correlations with TWSA.
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Ren, Zhiming, and Yang Liu. "A hierarchical elastic full-waveform inversion scheme based on wavefield separation and the multistep-length approach." GEOPHYSICS 81, no. 3 (May 2016): R99—R123. http://dx.doi.org/10.1190/geo2015-0431.1.
Повний текст джерелаАнотація:
Elastic full-waveform inversion (FWI) updates model parameters by minimizing the residuals of the P- and S-wavefields, resulting in more local minima and serious nonlinearity. In addition, the coupling of different parameters degrades the inversion results. To address these problems, we have developed a hierarchical elastic FWI scheme based on wavefield separation and a multistep-length gradient approach. First, we have derived the gradients expressed by different wave modes; analyzed the crosstalk between various parameters; and evaluated the sensitivity of separated P-wave, separated S-wave, and P- and S-wave misfit functions. Then, a practical four-stage inversion workflow was developed. In the first stage, conventional FWI is used to achieve rough estimates of the P- and S-wave velocities. In the second stage, we only invert the P-wave velocity applying the separated P-wavefields when strong S-wave energy is involved, or we merely update the S-wave velocity by matching the separated S-wavefields for the weak S-wave case. The PP and PS gradient formulas are used in these two cases, respectively. Therefore, the nonlinearity of inversion and the crosstalk between parameters are greatly reduced. In the third stage, the multistep-length gradient scheme is adopted. The density structure can be improved owing to the use of individual step lengths for different parameters. In the fourth stage, we make minor adjustments to the recovered P- and S-wave velocities and density by implementing conventional FWI again. Synthetic examples have determined that our hierarchical FWI scheme with the aforementioned steps obtains more plausible models than the conventional method. Inversion results of each stage and any three stages reveal that wavefield decomposition and the multistep-length approach are helpful to improve the accuracy of velocities and density, respectively, and all the stages of our hierarchical FWI method are necessary to give a good recovery of P- and S-wave velocities and density.
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Musialkowska, Ida, Agata Kliber, Katarzyna Świerczyńska, and Paweł Marszałek. "Looking for a safe-haven in a crisis-driven Venezuela." Transforming Government: People, Process and Policy 14, no. 3 (April 20, 2020): 475–94. http://dx.doi.org/10.1108/tg-01-2020-0009.
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Purpose This paper aims to find, which of the assets: gold, oil or bitcoin can be considered a safe-haven for investors in a crisis-driven Venezuela. The authors look also at the governmental change of approach towards the use and mining of cryptocurrencies being one of the assets and potential applications of bitcoin as (quasi) money. Design/methodology/approach The authors collected the daily data (a period from 01 May 2014 to 31 July 2018) on the development of the following magnitudes: Caracas Stock Exchange main index: Índice Bursátil de Capitalisación (IBC) index; gold price in US dollars, the oil price in US dollars and Bitcoin price in bolivar fuerte (VEF) (LocalBitcoins). The authors estimated a threshold VAR model between IBC and each of the possible safe-haven assets, where the trigger variable was the IBC; then the authors modelled the residuals from the TVAR model using MGARCH model with dynamic conditional correlation. Findings The results show that that gold is a better safe-haven than oil for Venezuelan investors, while bitcoin can be considered a weak safe haven. Still, bitcoin can perform (to a certain extent) money functions in a crisis-driven country. Research limitations/implications Further research after the change of local currency from VEF into bolivar soberano might be looked at on the later stage. Practical implications The authors provide evidence on which of analysed asset is the best safe-haven for the investors acting in the time of the crisis. The evidence goes in line with other authors’ findings, thus, the results might bring implications for investors of more universal character. Additionally, the result might be helpful for governments and/or monetary authorities while projecting institutional frameworks and conducting monetary policy. Social implications The unprecedented economic crisis in Venezuela was one of the factors that fuelled the mining and use of cryptocurrencies in the daily life of its citizens. Nowadays, the country is a leader in terms of the use of bitcoin and other cryptocurrencies in Latin America. The results show a potential application of bitcoin as a store of value or even means of payments in Venezuelan (or in other countries affected by the crisis). Originality/value The paper builds on the original data set collected by the authors and brings evidence from the models the authors constructed to verify, which asset is the best option for investors in hard times of the crisis. The authors add to the existing literature on financial assets, cryptocurrencies and behaviour of investors under different economic conditions.
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Baryshnikov, Sergei O., Alla B. Krasiuk, and Valentin B. Chistov. "THE INFLUENCE OF LOCAL RESIDUAL DEFORMATIONS ON THE SHIPS HULLS RELIABILITY." Vestnik Gosudarstvennogo universiteta morskogo i rechnogo flota imeni admirala S. O. Makarova 14, no. 3 (September 2, 2022): 403–16. http://dx.doi.org/10.21821/2309-5180-2022-14-3-403-416.
Повний текст джерелаАнотація:
The changes in the bearing capacity of the hull sheets and beams of the ship’s set under the action of compressive and tensile forces are studied in the paper. The inf luence of local residual deformations on the permissible wear of the deformed element, which allows assessing its reliability, is established. Since the longitudinal forces (compressive and tensile) are significant only for the deck or bottom in the middle part of the hull, the effect of local residual deformations on the bearing capacity of sheets and beams of the longitudinal set is estimated only for these elements. It is assumed that the retained local residual deformations of the housing elements do not change with the time of ship operation. Corrections for permissible wear in the cross-section equal to a decrease in the average thickness of the sheets in the cross-section are calculated (for a section of the body equal to the length of the sheet, from joint to joint). The wear rate of all cross-section sheets is assumed to be the same, and the probability of its occurrence corresponds to the law of normal distribution with the characteristics specified in the Rules of the Russian River Register established for a given group of elements. According to the assumptions made above, it is possible to calculate the probability of failure in the cross-section of a group of elements with local residual deformations depending on the number of years of the vessel operation. The probability of failures in a given group of elements is estimated by the multiplication of the failures probability in several sections after a given number of years of operation. The probability of failures in the hull of the vessel is calculated as the multiplication of the failures probabilities in all groups of elements. Formulas for calculating the loss of the bearing area of the sheathing plates and beams of the longitudinal set due to the local residual deformations have been obtained. The loss of the working area of the sheets and longitudinal beams is represented as additional wear of the sheets. After dividing the mentioned loss of the cross-section area by the cross-section width, the value of the permissible reduction in the residual thickness of the sheets, weighted average for the section under consideration, is obtained.
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Lam, William, Kalev Kask, Javier Larrosa, and Rina Dechter. "Residual-Guided Look-Ahead in AND/OR Search for Graphical Models." Journal of Artificial Intelligence Research 60 (October 20, 2017): 287–346. http://dx.doi.org/10.1613/jair.5475.
Повний текст джерелаАнотація:
We introduce the concept of local bucket error for the mini-bucket heuristics and show how it can be used to improve the power of AND/OR search for combinatorial optimization tasks in graphical models (e.g. MAP/MPE or weighted CSPs). The local bucket error illuminates how the heuristic errors are distributed in the search space, guided by the mini-bucket heuristic. We present and analyze methods for compiling the local bucket-errors (exactly and approximately) and show that they can be used to yield an effective tool for balancing look-ahead overhead during search. This can be especially instrumental when memory is restricted, accommodating the generation of only weak compiled heuristics. We illustrate the impact of the proposed schemes in an extensive empirical evaluation for both finding exact solutions and anytime suboptimal solutions.
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Weißer, Steffen, and Thomas Wick. "The Dual-Weighted Residual Estimator Realized on Polygonal Meshes." Computational Methods in Applied Mathematics 18, no. 4 (October 1, 2018): 753–76. http://dx.doi.org/10.1515/cmam-2017-0046.
Повний текст джерелаАнотація:
AbstractIn this work, we realize goal-oriented error estimation using the dual-weighted residual method on general polygonal meshes. Such meshes are of current interest in various applications thanks to their great flexibility. Specifically the discrete problems are treated on BEM-based FEM. Our dual-weighted residual estimator is derived for two localization procedures. Firstly, a classical (strong) localization. Secondly, a weak form is adopted in which localization is achieved with the help of a partition-of-unity. The dual (i.e., adjoint) solution is obtained via a local higher-order approximation using a single element. Our algorithmic developments are substantiated with the help of several numerical tests.
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Harlan, William S. "Wavelet balancing for residual moveouts." GEOPHYSICS 79, no. 6 (November 1, 2014): V217—V225. http://dx.doi.org/10.1190/geo2013-0479.1.
Повний текст джерелаАнотація:
Conventional moveout analysis stretches and squeezes traces to increase the coherence of reflected amplitudes in prestack seismic gathers. Higher order residual moveouts require increasingly difficult scans of semblances with extra dimensions or picking from correlations with many local minima. Alternatively, we can model our data with an adaptive convolution that assumes consistent reflectivities at all offsets (or angles). Short, convolutional wavelets can adjust residual moveouts arbitrarily with offset, but slowly with time (or depth). A Gauss-Newton optimization easily inverts this transform by minimizing a least-squares objective function. With estimated and normalized wavelets, we deconvolved the original data to remove phase and spectral distortions that affected more than one reflection. By constraining how slowly wavelets adapt, we retained phase and amplitude changes distinctive to individual reflections. Deconvolution also avoided any explicit smoothing or mixing of amplitudes among traces. Estimated wavelets captured residual coherence and were easier to track visually than individually weak reflections. By adjusting the length and number of independent dynamic wavelets, we can adjust the resolution to the redundancy supported by the data.
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Neupetsch, Constanze, Eric Hensel, Burkhard Kranz, Welf-Guntram Drossel, Thomas Felderhoff, and Christoph-Eckhard Heyde. "Proof of Concept for the Detection of Local Pressure Marks in Prosthesis Sockets Using Structural Dynamics Measurement." Sensors 21, no. 11 (May 31, 2021): 3821. http://dx.doi.org/10.3390/s21113821.
Повний текст джерелаАнотація:
The wear comfort of a prosthesis is of great importance for amputee patients. The wear comfort can be affected by changes in the interface between the residual limb and prosthesis socket, which can be caused by time-dependent volume fluctuations of the tissue, leading to unwanted local pressure marks. The basis to ensure time-independent wear comfort of a prosthesis is to identify these changes. Common techniques for identifying these variations have a negative impact on the sensitive interface between the residual limb and prosthesis. The following paper contains a proof of concept for the detection of local pressure marks without affecting the described interface using structural dynamics measurements, exemplarily shown at a prosthetic socket for transfemoral amputees in a test bench scenario. The dynamical behaviour of the investigated system is analysed in the form of frequency response functions acquired for different pressure locations and preloads using an impact hammer for excitation and a triaxial acceleration sensor. The frequency response functions show major changes for the various boundary conditions with respect to their frequency-dependent compositions. The results demonstrate how the utilised method enables the identification of changes in local pressure marks regarding the variation of position and magnitude.
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Guillon, Robin, Cédric Stéphan, Yannick Balcaen, Claudie Josse, Benoit Fori, Olivier Dalverny, and Joel Alexis. "An Estimation of Local Residual Stresses in Amorphous and Crystallized Trivalent Chromium Coatings." Coatings 13, no. 1 (January 9, 2023): 124. http://dx.doi.org/10.3390/coatings13010124.
Повний текст джерелаАнотація:
Hard chromium coatings have demonstrated their performance for several decades, particularly for their wear and corrosion resistance properties. However, the traditional process using chromium trioxide (CrO3) is very toxic and is intended to disappear in the European Union by 2024, thanks to the REACH regulation. This study aimed to determine the residual stress of amorphous chromium deposits elaborated from baths containing trivalent chromium ions. However, the amorphous structure of these deposits does not allow the determination of residual stresses by conventional means. In this study, we propose adapting a recent method called “FIB-DIC”, which is not limited by the material’s crystalline structure compared to the classical X-ray diffraction (XRD) analysis. The method is based on the measurement of relaxation-induced displacement fields following the ablation of material on a very local scale. The results obtained by the classical (XRD) and the FIB-DIC method on crystallized heat-treated Cr(III) deposits are 296 ± 45 and 377 ± 275 MPa. Then, the FIB-DIC technique allowed us to evaluate a residual stress level of 479 ± 359 MPa for amorphous trivalent chromium coating, which has never been performed before.
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Wang, Hongsu, Yoon Kyung Lee, Christine Xue та Zhefeng Guo. "Site-specific structural order in Alzheimer's Aβ42 fibrils". Royal Society Open Science 5, № 7 (липень 2018): 180166. http://dx.doi.org/10.1098/rsos.180166.
Повний текст джерелаАнотація:
Deposition of amyloid fibrils is a pathological hallmark of Alzheimer's disease. Aβ42 is the major protein whose aggregation leads to the formation of these fibrils. Understanding the detailed structure of Aβ42 fibrils is of particular importance for delineating the mechanism of Aβ42 aggregation and developing specific amyloid-targeting drugs. Here, we use site-directed spin labelling and electron paramagnetic resonance spectroscopy to study the site-specific structural order at each and every residue position in Aβ42 fibrils. Strong interactions between spin labels indicate highly ordered protein backbone at the labelling site, while weak interactions suggest disordered local structure. Our results show that Aβ42 consists of five β-strands (residues 2–7, 10–13, 17–20, 31–36, 39–41), three turns (residues 7–8, 14–16, 37–38) and one ordered loop (residues 21–30). Spin labels introduced at β-strand sites show strong spin–spin interactions, while spin labels at turn or loop sites show weak interactions. However, residues 24, 25 and 28 also show strong interactions between spin labels, suggesting that the loop 21–30 is partly ordered. In the context of recent structural work using solid-state NMR and cryoEM, the site-specific structural order revealed in this study provides a different perspective on backbone and side chain dynamics of Aβ42 fibrils.
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Murakami, Naoya, Seiichi Yoshimoto, Satoshi Nakamura, Masakazu Uematsu, Tairo Kashihara, Kana Takahashi, Koji Inaba, et al. "Per-oral interstitial brachytherapy catheter insertion for boost in case of recurrent tonsillar carcinoma: dosimetry and clinical outcome." BJR|case reports 6, no. 1 (March 2020): 20190059. http://dx.doi.org/10.1259/bjrcr.20190059.
Повний текст джерелаАнотація:
High-dose-rate interstitial brachytherapy (HDR-ISBT) is relatively rarely applied for the head and neck cancer. However, its dose distribution is more confined than intensity modulated radiation therapy (IMRT) and can deliver higher dose while sparing surrounding normal tissues. In this case report, the effectiveness of HDR-ISBT as a boost following IMRT for post-operative recurrent oropharyngeal cancer patient was indicated. A 73-year-old male who developed local recurrence after surgery for oropharyngeal squamous cell carcinoma. Salvage IMRT up to 70 Gy concurrent with weekly cetuximab was planned. However, CT taken at 60 Gy found a residual tumor, then, boost HDR-ISBT was proposed. 1 week after 60 Gy of IMRT, HDR-ISBT, 12 Gy in 2 fractions, was delivered under local anesthesia. MRI taken 2 months after HDR-ISBT showed no residual tumor. It was demonstrated that boost HDR-ISBT following IMRT for local recurrence of oropharyngeal cancer was performed safely and showed favorable efficacy.
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Roth, A., J. Schneider, T. Klimach, S. Mertes, D. van Pinxteren, H. Herrmann, and S. Borrmann. "Aerosol properties, source identification, and cloud processing in orographic clouds measured by single particle mass spectrometry on a Central European mountain site during HCCT-2010." Atmospheric Chemistry and Physics Discussions 15, no. 17 (September 8, 2015): 24419–72. http://dx.doi.org/10.5194/acpd-15-24419-2015.
Повний текст джерелаАнотація:
Abstract. Cloud residues and out-of-cloud aerosol particles with diameters between 150 and 900 nm have been analysed by on-line single particle aerosol mass spectrometry during the six-week study HCCT-2010 in September/October 2010. The measurement location was the mountain Schmücke (937 m a.s.l.) in Central Germany. More than 170 000 bipolar mass spectra from out-of-cloud aerosol particles and more than 14 000 bipolar mass spectra from cloud residual particles were obtained and were classified using a fuzzy c-means clustering algorithm. Analysis of the uncertainty of the sorting algorithm was conducted on a subset of the data by comparing the clustering output with particle-by-particle inspection and classification by the operator. This analysis yielded a false classification probability between 13 and 48 %. Additionally, particle types were identified by specific marker ions. The results from the ambient aerosol analysis show that 63 % of the analysed particles belong to clusters indicating a diurnal variation, suggesting that local or regional sources dominate the aerosol, especially for particles containing soot and biomass burning particles. In the cloud residues the relative percentage of large soot-containing particles and particles containing amines was found to be increased compared to the out-of-cloud aerosol, while in general organic particles were less abundant in the cloud residues. In the case of amines this can be explained by the high solubility of the amines, while the large soot-containing particles were found to be internally mixed with inorganics, which explains their activation as cloud condensation nuclei. Furthermore, the results show that during cloud processing, both sulphate and nitrate are added to the residual particles, thereby changing the mixing state and increasing the fraction of particles with nitrate and/or sulphate. This is expected to lead to higher hygroscopicity after cloud evaporation, and therefore to an increase of the particles' ability to act as cloud condensation nuclei after their cloud passage.
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Roth, A., J. Schneider, T. Klimach, S. Mertes, D. van Pinxteren, H. Herrmann, and S. Borrmann. "Aerosol properties, source identification, and cloud processing in orographic clouds measured by single particle mass spectrometry on a central European mountain site during HCCT-2010." Atmospheric Chemistry and Physics 16, no. 2 (January 19, 2016): 505–24. http://dx.doi.org/10.5194/acp-16-505-2016.
Повний текст джерелаАнотація:
Abstract. Cloud residues and out-of-cloud aerosol particles with diameters between 150 and 900 nm were analysed by online single particle aerosol mass spectrometry during the 6-week study Hill Cap Cloud Thuringia (HCCT)-2010 in September–October 2010. The measurement location was the mountain Schmücke (937 m a.s.l.) in central Germany. More than 160 000 bipolar mass spectra from out-of-cloud aerosol particles and more than 13 000 bipolar mass spectra from cloud residual particles were obtained and were classified using a fuzzy c-means clustering algorithm. Analysis of the uncertainty of the sorting algorithm was conducted on a subset of the data by comparing the clustering output with particle-by-particle inspection and classification by the operator. This analysis yielded a false classification probability between 13 and 48 %. Additionally, particle types were identified by specific marker ions. The results from the ambient aerosol analysis show that 63 % of the analysed particles belong to clusters having a diurnal variation, suggesting that local or regional sources dominate the aerosol, especially for particles containing soot and biomass burning particles. In the cloud residues, the relative percentage of large soot-containing particles and particles containing amines was found to be increased compared to the out-of-cloud aerosol, while, in general, organic particles were less abundant in the cloud residues. In the case of amines, this can be explained by the high solubility of the amines, while the large soot-containing particles were found to be internally mixed with inorganics, which explains their activation as cloud condensation nuclei. Furthermore, the results show that during cloud processing, both sulfate and nitrate are added to the residual particles, thereby changing the mixing state and increasing the fraction of particles with nitrate and/or sulfate. This is expected to lead to higher hygroscopicity after cloud evaporation, and therefore to an increase of the particles' ability to act as cloud condensation nuclei after their cloud passage.
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Miyazawa, Haruna, Takako Nakajima, Makoto Horimizu, Kazuhiro Okuda, Noriko Sugita, Kyoko Yamazaki, Lu Li, et al. "Impact of Local Drug Delivery of Minocycline on the Subgingival Microbiota during Supportive Periodontal Therapy: A Randomized Controlled Pilot Study." Dentistry Journal 8, no. 4 (October 27, 2020): 123. http://dx.doi.org/10.3390/dj8040123.
Повний текст джерелаАнотація:
The aim of this study was to examine the effect of adjunct local minocycline administration on the microbiological parameters of subgingival plaque samples in the residual periodontal pockets. Ten chronic periodontitis patients under a supportive periodontal therapy regimen were recruited. After subgingival debridement, either 2% minocycline gel, Periocline™, (Test Group) or a placebo (Control Group) was administered to the selected sites once a week for three weeks. Subgingival plaque was collected at baseline, and at four weeks and eight weeks. The microbiological composition was analyzed by 16S ribosomal RNA sequencing. In the Test Group, α-diversity (evenness) decreased compared to the baseline (p = 0.005) and was lower compared to the control group at four weeks (p = 0.003). The microbial community composition between the two groups was significantly different at four weeks (p = 0.029). These changes were attributable to a decrease in the bacteria associated with periodontitis and an increase in the bacteria associated with periodontal health. Additionally, the improvement in bleeding on probing continued at eight weeks; however, there were little microbial effects of 2% minocycline gel observed at eight weeks. The control group demonstrated no change throughout the eight-week experimental period. Thus, local minocycline administration can change the subgingival microbial community of residual periodontal pockets.
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Wang, Junyuan, Xiaofeng Han, Zhijian Wang, Wenhua Du, Jie Zhou, Jiping Zhang, Huihui He, and Xiaoming Guo. "Modified Singular Spectrum Decomposition and Its Application to Composite Fault Diagnosis of Gearboxes." Sensors 19, no. 1 (December 24, 2018): 62. http://dx.doi.org/10.3390/s19010062.
Повний текст джерелаАнотація:
Under the strong noise environment, the composite fault signal of gearbox is weak, which makes it difficult to extract fault features. For this problem, based on noise-assisted method, we propose a novel method called Modified Singular Spectrum Decomposition (MSSD). Singular Spectrum Decomposition (SSD) has many advantages such as high decomposition precision and strong ability to restrain mode mixing, etc. However, the ability of SSD to extract a weak signal is not ideal, the decomposition results usually contain a lot of redundant noise and mode mixing caused by intermittency, which is also a troubling problem. In order to improve the decomposition efficiency and make up for the defects of SSD, the new method MSSD adds an adaptive and particular noise in every SSD decomposition stage for each trial, and in addition, whenever the input signal is decomposed to obtain an intrinsic module function (IMF), a unique residual is obtained. After multiple decomposition, the average value of the residual is used as input to the next stage, until the residual cannot continue to decompose, which means that the residual component has, at most, one extreme value. Finally, analyzing simulated signals to explain the advantages of MSSD compared to ensemble empirical mode decomposition (EEMD) and complete ensemble local mean decomposition with adaptive noise (CEEMDAN). In order to further prove the effectiveness of MSSD, this new method, MSSD, is applied to the fault diagnosis of an engineering gearbox test stand in an actual engineer project case. The final results show that MSSD can extract more fault feature information, and mode mixing has been improved and suffers less interference compared to SSD.
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Mikhalchenkov, Alexander, Sergey Feskov, and Andrey Kubyshkin. "WEAR OF PARTS OF THE WORKING BODY OF THE PSKU HIGH-SPEED PLOW." SCIENCE IN THE CENTRAL RUSSIA, no. 5 (October 31, 2022): 37–47. http://dx.doi.org/10.35887/2305-2538-2022-5-37-47.
Повний текст джерелаАнотація:
The use of high-speed plows manufactured in the Russian Federation is due to the intensification of field work and the problem of import substitution. The purpose of the research is to study the wear of the structural elements of the working body of the plow of the PSKu series. The parameters for assessing the technical condition of parts taken out of service were changes in linear dimensions (linear wear). The number of controlled parts for each item was 27 units. Plowing was carried out on loamy soils - 25 ha per product. Research has established that the wear geometry of the surfaces of the left knives has a complex configuration, and the maximum wear in width and thickness is not critical, so the part is suitable for further operation. The control of the right knives according to the residual thickness and the amount of wear of the blade showed that they are in working condition, and the wear of the penetrating area has a radial character and is located in two sections. Typical for vertical knives is radial wear that extends to the side. The thinning of the cutting area leads to local through rubbing of the part. The suitability of these knives for further operation and restoration is determined by their permissible residual width and thickness. The limiting wear of vertical knives determines the working state of the working body. Radiation wear is a defining defect for dumps, although it does not reach its limit value in terms of residual thickness. Therefore dumps after an operating time of 25 hectares are suitable for operation. Thus, the controlled parts are suitable for further operation, however, it is necessary to carry out hardening operations.
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Yin, Haoran, Jinxuan Cao, Luzhe Cao, and Guodong Wang. "Chinese Emergency Event Recognition Using Conv-RDBiGRU Model." Computational Intelligence and Neuroscience 2020 (May 21, 2020): 1–12. http://dx.doi.org/10.1155/2020/7090918.
Повний текст джерелаАнотація:
In view of the weak generalization of traditional event recognition methods, the limitation of dependence on field knowledge of expert, the longer train time of deep neural network, and the problem of gradient dispersion, the neural network joint model, Conv-RDBiGRU, integrated residual structure was proposed. Firstly, text corpus is preprocessed by word segmentation and stop words processing and uses word embedding to form the matrix of word vectors. Then, local semantic features are extracted through convolution operation, and deep context semantic features are extracted through RDBiGRU. Finally, the learned features are activated by softmax function and the recognition results are output. The novelty of work is that we integrate residual structure into recurrent neural network and combine these methods and field of application. The simulation results show that this method improves precision and recall of Chinese emergency event recognition, and the F-value is better than other methods.
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Cadamuro, Daniela, and Yoh Tanimoto. "Wedge-local observables for factorizing S-matrix with gap in the coupling constant." Reviews in Mathematical Physics 30, no. 04 (April 19, 2018): 1850010. http://dx.doi.org/10.1142/s0129055x18500101.
Повний текст джерелаАнотація:
In the bootstrap approach to integrable quantum field theories in the [Formula: see text]-dimensional Minkowski space, one conjectures the two-particle S-matrix and tries to study local observables. We find a family of two-particle S-matrices parametrized by two positive numbers, which are separated from the free field or any other known S-matrix. We propose candidates for observables in wedge-shaped regions and prove their commutativity in the weak sense. The sine-Gordon model is conjectured to be equivalent to the Thirring model, and its breather–breather S-matrix components (where the first breather corresponds to the scalar field of the sine-Gordon model) are closed under fusion. Yet, the residues of the poles in this breather–breather S-matrix have wrong signs and cannot be considered as a separate model. Our S-matrices differ from the breather–breather S-matrix in the sine-Gordon model by CDD factors which adjust the signs, so that this sector alone satisfies reasonable assumptions.
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Inose, Hiroyuki, Tsuyoshi Kato, Shoichi Ichimura, Hiroaki Nakamura, Masatoshi Hoshino, Shinji Takahashi, Daisuke Togawa, et al. "Factors Contributing to Residual Low Back Pain after Osteoporotic Vertebral Fractures." Journal of Clinical Medicine 11, no. 6 (March 12, 2022): 1566. http://dx.doi.org/10.3390/jcm11061566.
Повний текст джерелаАнотація:
Although osteoporotic vertebral fractures (OVFs) are the most common type of osteoporotic fracture, few reports have investigated the factors contributing to residual low back pain in the chronic phase after OVFs by using radiographic evaluation. We examined the contribution of nonunion, vertebral deformity, and thoracolumbar alignment to the severity of residual low back pain post-OVF. This post hoc analysis of a prospective randomized study included 195 patients with a 48-week follow-up period. We investigated the associations between radiographic variables with the visual analog scale (VAS) scores for low back pain at 48 weeks post-OVF using a multiple linear regression model. Univariate analysis revealed that analgesic use, the local angle on magnetic resonance imaging, anterior vertebral body compression percentage on X-ray, and nonunion showed a significant association with VAS scores for low back pain. Multiple regression analysis produced the following equation: VAS for low back pain at 48 weeks = 15.49 + 0.29 × VAS for low back pain at 0 weeks + (with analgesics: +8.84, without analgesics: −8.84) + (union: −5.72, nonunion: −5.72). Among local alignment, thoracolumbar alignment, and nonunion, nonunion independently contributed to residual low back pain at 48 weeks post-OVF. A treatment strategy that reduces the occurrence of nonunion is desirable.
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Shcherbyna, Nadiia. "Libraries and their activities in the context of historical and local history development in the region." Bulletin of Luhansk Taras Shevchenko National University, no. 4 (342) (2021): 176–87. http://dx.doi.org/10.12958/2227-2844-2021-4(342)-176-187.
Повний текст джерелаАнотація:
The article reveals the historical and local history activities of the libraries of the Odessa region in the second half of the 40s – 80s XX century. The analysis of this activity indicates that despite the great difficulties (the residual principle of financing culture, and the weak material and technical base of libraries), they have become real centers of local history work in the region. During this period, libraries have accumulated a significant bibliographic base on local history issues, acquired extensive experience in working with local history research. In the development of library local lore, an important role was played by bibliographers of local lore of Odessa scientific libraries. Thanks to their activities, a local history fund was collected in almost every library, catalogs and card indexes were created, which included numerous materials on various local history topics. That is why libraries performed the social functions of education and culture units and became centers of local history. However, the regional studies of the regional libraries require further in-depth study, because by that time they, acting as regional information centers, were engaged in the search, storage and provision of local history literature for public use. The development of library local lore in the region was negatively affected by those general tendencies of social life arising from the very nature of the then totalitarian regime.
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Trojan, Karel, Václav Ocelík, Jiří Čapek, Jaroslav Čech, David Canelo-Yubero, Nikolaj Ganev, Kamil Kolařík, and Jeff T. M. De Hosson. "Microstructure and Mechanical Properties of Laser Additive Manufactured H13 Tool Steel." Metals 12, no. 2 (January 27, 2022): 243. http://dx.doi.org/10.3390/met12020243.
Повний текст джерелаАнотація:
Hot working tool steel (AISI H13) is one of the most common die materials used in casting industries. A die suffers from damage due to friction and wear during its lifetime. Therefore, various methods have been developed for its repair to save costs to manufacture a new one. A great benefit of laser additive manufacturing (cladding) is the 3D high production rate with minimal influence of thermal stresses in comparison with conventional arc methods. Residual stresses are important factors that influence the performance of the product, especially fatigue life. Therefore, the aim of this contribution is to correlate the wide range of results for multilayer cladding of H13 tool steel. X-ray and neutron diffraction experiments were performed to fully describe the residual stresses generated during cladding. Additionally, in-situ tensile testing experiments inside a scanning electron microscope were performed to observe microstructural changes during deformation. The results were compared with local hardness and wear measurements. Because laser cladding does not achieve adequate accuracy, the effect of necessary post-grinding was investigated. According to the findings, the overlapping of beads and their mutual tempering significantly affect the mechanical properties. Further, the outer surface layer, which showed tensile surface residual stresses and cracks, was removed by grinding and surface compressive residual stresses were described on the ground surface.
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Jaramillo, María Fernanda, Alberto Galvis, Marisa Escobar, Laura Forni, David Purkey, Jack Siebel, Gabriel Lozano, Cesar Rodríguez, Juan Castaño, and Carlos Sabas. "Integración de los modelos WEAP y QUAL2K para la simulación de la calidad agua de fuentes superficiales. Caso de estudio: cuenca del río La Vieja, Colombia." Aqua-LAC 8, no. 2 (September 30, 2016): 14–24. http://dx.doi.org/10.29104/phi-aqualac/2016-v8-2-02.
Повний текст джерелаАнотація:
En esta investigación se evaluó el impacto de las aguas residuales domésticas y agroindustriales en la cuenca del río La Vieja, Colombia, considerando como factores para la evaluación el crecimiento poblacional, el desarrollo agroindustrial y los efectos de la variabilidad y el cambio climático. La evaluación de la calidad del agua se logró mediante la integración de las herramientas de modelación WEAP (Water Evaluation And Planning System) y QUAL2K, que permitió realizar el análisis dendrítico (sistema ramificado de 11 fuentes hídricas que tributan al cauce principal) del comportamiento de la cantidad y la calidad del agua del río La Vieja. La cuenca del río La Vieja se localiza al centro sur de Colombia, con una extensión aproximadamente de 2.880 km2. Las principales ventajas de la integración de los modelos corresponden a la posibilidad de modificar la cinética de degradación de los contaminantes por tramo de río en el modelo QUAL2K y la dinamización de los resultados de este modelo en pasos de tiempo mensual, beneficio que aporta el modelo de planificación WEAP. La integración de modelos tuvo como resultado principal la identificación del comportamiento espacio temporal de los parámetros de calidad del agua Oxígeno Disuelto (OD), Demanda Bioquímica de Oxígeno (DBO5) y Temperatura (T) en una escala de agregación mensual en el año de línea base considerado como 2011 y la evaluación de la implementación de dos estrategias de control de la contaminación hídrica: sistemas de tratamiento de aguas residuales municipales y sistemas de tratamiento anaerobio para la remoción de carga orgánica en el beneficio del café. Los valores de concentración de DBO no superan los 5 mg/l en el escenario de línea base. La concentración de OD se encontró entre 4 y 9.5 mg/l. Los resultados obtenidos, representan el comportamiento del río La Vieja, que cumple con la normatividad local para los usos actuales del agua
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Rosati, Lauren M., Shalini Moningi, Amy Hacker-Prietz, Dan Laheru, Lei Zheng, Ana De Jesus-Acosta, Dung T. Le, et al. "A prospective study evaluating stereotactic body radiation therapy in unresectable, recurrent, or residual pancreatic adenocarcinoma." Journal of Clinical Oncology 34, no. 4_suppl (February 1, 2016): 454. http://dx.doi.org/10.1200/jco.2016.34.4_suppl.454.
Повний текст джерелаАнотація:
454 Background: The purpose of this prospective, non-randomized phase II single-institution study was to evaluate if local control can be achieved with reasonable acute and late GI toxicity using fractionated SBRT in patients with unresectable, recurrent, or residual locally advanced pancreatic cancer (LAPC). Methods: A total of 24 patients with LAPC were enrolled from June 2013 to August 2014. Eligibility required stability after induction chemotherapy or residual disease or local failure after surgery. Induction chemotherapy regimens consisted of: (1) gemcitabine alone (8%); (2) gemcitabine-based regimens (17%); (3) FOLFIRINOX-based regimens (63%); or (4) combination regimens (13%). Chemotherapy was discontinued one week prior to SBRT. Patients received a median cumulative dose of 33 Gy in 5 fractions (5-6.6 Gy/fraction). Patients were permitted to resume chemotherapy one week post-SBRT. Toxicity was assessed using the NCI CTCAE version 4.0. Results: Of the 24 patients, 58% were male and 50% had tumors in the head of the pancreas. Median age at diagnosis was 66.8 years, and median follow-up from the date of diagnosis was 11.9 months (range, 7.4-29.7 months). There have not been any acute or late grade ≥ 2 gastritis, enteritis, fistula, or ulcer toxicities (primary endpoint). Median OS has not yet been reached, median LPFS was 19.3 months (95% CI, 12.3-14.8), median DMFS was 13.6 months (95% CI, 9.2-17.9) and median PFS was 13.6 months (95% CI, 13.5-25.2). Plasma CA 19-9 level was non-significantly reduced after SBRT, displaying a -9.15 average percent change from baseline (median time after SBRT, 1.2 months). FFLP at 1 year was 83.9%. Eight (33%) patients underwent successful surgery following SBRT, with rates of both margin- and node-negative resection being 75%. Conclusions: Chemotherapy followed by fractionated SBRT results in favorable local control and survival with minimal acute and late GI toxicity. A notable proportion of patients initially deemed unresectable underwent successful resection. This study suggests that SBRT can be safely given following more aggressive multiagent chemotherapy in patients with LAPC. Clinical trial information: NCT01781728.
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Chan, Steven C., and Sumant Nigam. "Residual Diagnosis of Diabatic Heating from ERA-40 and NCEP Reanalyses: Intercomparisons with TRMM." Journal of Climate 22, no. 2 (January 15, 2009): 414–28. http://dx.doi.org/10.1175/2008jcli2417.1.
Повний текст джерелаАнотація:
Abstract Diabatic heating is diagnosed from the 40-yr ECMWF Re-Analysis (ERA-40) circulation as a residue in the thermodynamic equation. The heating distribution is compared with the heating structure diagnosed from NCEP and 15-yr ECMWF Re-Analysis (ERA-15) circulation and latent heating generated from Tropical Rainfall Measuring Mission (TRMM) observations using the convective–stratiform heating (CSH) algorithm. The ERA-40 residual heating in the tropics is found to be stronger than NCEP’s (and ERA-15), especially in July when its zonal–vertical average is twice as large. The bias is strongest over the Maritime Continent in January and over the eastern basins and Africa in July. Comparisons with precipitation indicate ERA-40 heating to be much more realistic over the eastern Pacific but excessive over the Maritime Continent, by at least 20% in January. Intercomparison of precipitation estimates from heating-profile integrals and station and satellite analyses reveals the TRMM CSH latent heating to be chronically weak by as much as a factor of 2! It is the low-side outlier among nine precipitation estimates in three of the four analyzed regions. No less worrisome is the inconsistency between the integral of the CSH latent heating profile in the tropics and the TRMM precipitation retrievals constraining the CSH algorithm (e.g., the 3A25 analysis). Confronting TRMM’s diagnosis of latent heating from local rainfall retrievals and local cumulus-model heating profiles with heating based on the large-scale assimilated circulation is a defining attribute of this study.
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Burt, Jonathan M., and Iain D. Boyd. "Convergence Detection in Direct Simulation Monte Carlo Calculations for Steady State Flows." Communications in Computational Physics 10, no. 4 (October 2011): 807–22. http://dx.doi.org/10.4208/cicp.090210.311210a.
Повний текст джерелаАнотація:
AbstractA new criterion is presented to detect global convergence to steady state, and to identify local transient characteristics, during rarefied gas flow simulations performed using the direct simulation Monte Carlo (DSMC) method. Unlike deterministic computational fluid dynamics (CFD) schemes, DSMC is generally subject to large statistical scatter in instantaneous flow property evaluations, which prevents the use of residual tracking procedures as are often employed in CFD simulations. However, reliable prediction of the time to reach steady state is necessary for initialization of DSMC sampling operations. Techniques currently used in DSMC to identify steady state convergence are usually insensitive to weak transient behavior in small regions of relatively low density or recirculating flow. The proposed convergence criterion is developed with the goal of properly identifying such weak transient behavior, while adding negligible computational expense and allowing simple implementation in any existing DSMC code. Benefits of the proposed technique over existing convergence detection methods are demonstrated for representative nozzle/plume expansion flow, hypersonic blunt body flow and driven cavity flow problems.
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Wang, Shubin, Yukun Tian, Xiaogang Deng, Qianlei Cao, Lei Wang, and Pengxiang Sun. "Disturbance Detection of a Power Transmission System Based on the Enhanced Canonical Variate Analysis Method." Machines 9, no. 11 (November 6, 2021): 272. http://dx.doi.org/10.3390/machines9110272.
Повний текст джерелаАнотація:
Aiming at the characteristics of dynamic correlation, periodic oscillation, and weak disturbance symptom of power transmission system data, this paper proposes an enhanced canonical variate analysis (CVA) method, called SLCVAkNN, for monitoring the disturbances of power transmission systems. In the proposed method, CVA is first used to extract the dynamic features by analyzing the data correlation and establish a statistical model with two monitoring statistics T2 and Q. Then, in order to handling the periodic oscillation of power data, the two statistics are reconstructed in phase space, and the k-nearest neighbor (kNN) technique is applied to design the statistics nearest neighbor distance DT2 and DQ as the enhanced monitoring indices. Further considering the detection difficulty of weak disturbances with the insignificant symptoms, statistical local analysis (SLA) is integrated to construct the primary and improved residual vectors of the CVA dynamic features, which are capable to prompt the disturbance detection sensitivity. The verification results on the real industrial data show that the SLCVAkNN method can detect the occurrence of power system disturbance more effectively than the traditional data-driven monitoring methods.
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Hussain, Muzammil, Kiran Aftab, Munawar Iqbal, Shafaqat Ali, Muhammad Rizwan, Saad Alkahtani, and Mohamed M. Abdel-Daim. "Determination of Pesticide Residue in Brinjal Sample Using HPTLC and Developing a Cost-Effective Method Alternative to HPLC." Journal of Chemistry 2020 (September 18, 2020): 1–12. http://dx.doi.org/10.1155/2020/8180320.
Повний текст джерелаАнотація:
Two analytical techniques HPLC (high performance liquid chromatography) and HPTLC (high performance thin layer chromatography) were validated to reveal the quality and quantity of pesticide residues (organophosphorus, organochlorine, and pyrethroids) in brinjal samples collected from a local market of Faisalabad. The HPTLC methods showed linear behavior for standard samples and residue was in the range of 1–130 ng. The organochlorine (α-endosulfan) contaminates the samples at 4, 5, 9, and 10 weeks, and detected quantity was less than MRL (minimum residue level) of the FAO (Food and Agriculture Organization of United Nations), i.e., 0.5 mg·kg−1. The organophosphorus pesticide (chlorpyriphos, methamidophos, monocrotophos, dichlorvos, carbosulfan, profenophos, and dimethoate) residue contaminated the samples and violated the MRL limit. Pyrethroids (deltamethrin, β-cyhalothrin, and cypermethrin) were present at appreciable levels, in samples of 1, 3, 4, 6, 8, and 9 weeks. The concentration of β-cyhalothrin (0.25 mg·kg−1) and cypermethrin (0.205 mg·kg−1) was significantly higher than that of all detected pesticides. The carbosulfan and deltamethrin contaminated all 10-week samples. The HPLC analysis of samples was carried out to confirm the efficiency of HPTLC as cost-effective method. The concentration of α-endosulfan, chlorpyriphos, dimethoate, monocrotophos, profenophos, deltamethrin, and cypermethrin in brinjal samples through the HPTLC method showed similar residual concentration with HPLC analysis.
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Gupta, Ankita, Treshita Dey, Bhavana Rai, Arun S. Oinam, Srinivasa GY, and Sushmita Ghoshal. "Point-Based Brachytherapy in Cervical Cancer With Limited Residual Disease: A Low- and Middle-Income Country Experience in the Era of Magnetic Resonance–Guided Adaptive Brachytherapy." JCO Global Oncology, no. 7 (September 2021): 1602–9. http://dx.doi.org/10.1200/go.21.00147.
Повний текст джерелаАнотація:
PURPOSE To evaluate the clinical outcomes in patients with cervical cancer with limited residual disease at brachytherapy (BT) treated with point-based dose prescription. METHODS Patients with locally advanced squamous cell carcinoma of the cervix treated with computed tomography (CT)-based intracavitary BT were considered for analysis. Patients with good response to external beam radiotherapy and limited residual disease suitable for intracavitary BT alone were included. Postapplication CT scans were performed before each fraction and individual plans were made for each session. The dose per fraction was 9Gy high dose rate, prescribed to point-A. Two sessions were planned, 1 week apart. The organs at risk were contoured, and cumulative dose-volume histograms were computed. Local control, pelvic control, disease-free survival, and overall survival were evaluated and late toxicities were documented. RESULTS Four hundred ninety patients were included. Overall, 79.8% had International Federation of Gynecology and Obstetrics (FIGO) stage IB2 to IIB disease and 20.2% had stage III to IVA disease. Median dose at point A (EQD210Gy) was 74.4 Gy (interquartile range [IQR] 72.3-74.5 Gy) and median D2cc (EQD23Gy) for bladder, rectum, and sigmoid were 82.5 Gy (IQR, 65.5-90.8 Gy), 66.5 Gy (IQR, 60.7-75.7 Gy), and 54.1 Gy (IQR, 50.5-77.3 Gy), respectively. At a median follow-up of 62 (IQR, 33-87) months, the 5-year local and pelvic control rates were 90.1% and 88.3%, respectively. The 5-year disease-free survival was 80% and overall survival was 88%. Rates of grade 3-4 bladder and rectosigmoid toxicities were 6.93% and 4.08%, respectively. CONCLUSION In patients with limited residual disease at BT, point-based dose prescription with CT planning results in good local control and acceptable toxicity. In a resource-constrained setting, patients may be triaged to receive point-based BT or magnetic resonance imaging–guided adaptive BT depending on the extent of residual disease.
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Schlicht, Hans, and Hermann Vetters. "Residual Stresses in Roller Bearing Components." Materials Science Forum 768-769 (September 2013): 755–61. http://dx.doi.org/10.4028/www.scientific.net/msf.768-769.755.
Повний текст джерелаАнотація:
Rolling contact fatigue is a very complex process. The mechanism can only be described by speculative considerations. Because the loading conditions during the elastic- hydro- dynamical contact are not clearly described. The loading cycle runs within extremely short rates and structural alterations occur under high hydrostatic pressure. Widely unknown is therefore, how the materials conditions are influenced by these processes. But by means of simplified considerations an approach to the rolling contact fatigue process can be obtained. Following these conceptions simplifying quasi-static conditions are drawn. A lubricant film inhibits the metallic contact of the revolved bearing components. A HERTZian load stress will be accumulated over an elliptical contact area and within and beneath this contact area three dimensional stresses are acting. The materials strengthening can be described by the hypothesis of alteration of shape. During the fatigue period, the microstructure will be changed by micro- and macro- plastically deformation. By this residual stresses occur. These are superimposed to the operational -loading –stresses which change the distressing conditions of the material. The progressive plastically deformations accompanying the growing fatigue procedure cause perpetually alterations in the distress- conditions of the material. Structural alterations of the rolling contact fatigue process are shown by means of metallography as followed: by dark etching areas (DEA), and by white etching areas (WEA) showing bands, which are positioned beneath the contact area at an angle of 30° (30°WEB) and for instance at 80° (80°WEB), and furthermore by so called butterfly structures (butterflies with “white etched” flanks). All these white etching areas, regarding their morphological structure and the etching conditions, are commonly originated by two axial distressing. The three dimensional materials distressing within the roller-bearing component on the one hand and the two dimensionally originating of the WEA on the other seem to be an antagonism. But when the changes of residual stresses during the contact rolling fatigue process are to be analyzed, it is clear that this antagonism rises only virtually because there exists a real tri-axial stress condition, which tolerates a two axial distressing of the material. By the concept, that the growing plastically deformations cause residual stresses superposing the operational load stresses, the temporary cycle of the structural alterations and the local and angular positions of the 30° WEB can be explained.
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Adams, Brian M., and Juan Diego Jaramillo. "A two-dimensional study on the weak-motion seismic response of the Aburra Valley, Medellin, Colombia." Bulletin of the New Zealand Society for Earthquake Engineering 35, no. 1 (March 31, 2002): 17–41. http://dx.doi.org/10.5459/bnzsee.35.1.17-41.
Повний текст джерелаАнотація:
A two-dimensional elastic finite-element method is used to investigate the weak-motion seismic response of the Aburra Valley of Medellin, Colombia. A vertically propagating anti- plane SH Ricker wavelet is used to study the response of the valley for frequencies up to 5 Hz. The Aburra Valley is very large and geologically diverse. The -1200-metre-deep and -15- kilometre-wide valley is covered by a variable layer of soft soils averaging some 30 metres deep. The soils are mainly residual, alluvial or debris-flow deposits. The valley also contains a network of 24 strong-motion seismic recorders. A 49,900-element mesh of a cross-sectional model through the southern end of Medellin is analysed using the finite-element software package, Archimedes. The results are presented in both time and frequency domains. A similar one-dimensional finite-element method is used for comparison. It is found that while amplification often occurs at frequencies defined by a one-dimensional analysis, the level of amplification is often highly dependent on multi-dimensional effects. Local irregularities in the stratigraphy and topography at some sites have a significant effect on the seismic response. Site response may also be influenced strongly by sub-valley structures up to a few kilometres across, yet the influence of the valley as a whole is small. Poor correlation between modelling results and recorded data is probably due to a lack of site-specific detail within the model, and the limiting two-dimensional nature of the analysis.
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Oliveira, Tiago, Wilber Vélez, and Artur Portela. "Formulation of local numerical methods in linear elasticity." Multidiscipline Modeling in Materials and Structures 16, no. 5 (June 4, 2020): 853–86. http://dx.doi.org/10.1108/mmms-05-2018-0094.
Повний текст джерелаАнотація:
PurposeThis paper is concerned with new formulations of local meshfree and finite element numerical methods, for the solution of two-dimensional problems in linear elasticity.Design/methodology/approachIn the local domain, assigned to each node of a discretization, the work theorem establishes an energy relationship between a statically admissible stress field and an independent kinematically admissible strain field. This relationship, derived as a weighted residual weak form, is expressed as an integral local form. Based on the independence of the stress and strain fields, this local form of the work theorem is kinematically formulated with a simple rigid-body displacement to be applied by local meshfree and finite element numerical methods. The main feature of this paper is the use of a linearly integrated local form that implements a quite simple algorithm with no further integration required.FindingsThe reduced integration, performed by this linearly integrated formulation, plays a key role in the behavior of local numerical methods, since it implies a reduction of the nodal stiffness which, in turn, leads to an increase of the solution accuracy and, which is most important, presents no instabilities, unlike nodal integration methods without stabilization. As a consequence of using such a convenient linearly integrated local form, the derived meshfree and finite element numerical methods become fast and accurate, which is a feature of paramount importance, as far as computational efficiency of numerical methods is concerned. Three benchmark problems were analyzed with these techniques, in order to assess the accuracy and efficiency of the new integrated local formulations of meshfree and finite element numerical methods. The results obtained in this work are in perfect agreement with those of the available analytical solutions and, furthermore, outperform the computational efficiency of other methods. Thus, the accuracy and efficiency of the local numerical methods presented in this paper make this a very reliable and robust formulation.Originality/valuePresentation of a new local mesh-free numerical method. The method, linearly integrated along the boundary of the local domain, implements an algorithm with no further integration required. The method is absolutely reliable, with remarkably-accurate results. The method is quite robust, with extremely-fast computations.
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SAJJAD ATHAR, M., S. CHAUHAN, S. K. SINGH, and M. J. VICENTE VACAS. "NEUTRINO NUCLEUS CROSS-SECTIONS." International Journal of Modern Physics E 18, no. 07 (August 2009): 1469–81. http://dx.doi.org/10.1142/s0218301309013774.
Повний текст джерелаАнотація:
We present the results of our calculation which has been performed to study the nuclear effects in the quasielastic, inelastic and deep inelastic scattering of neutrinos(antineutrinos) from nuclear targets. These calculations are done in the local density approximation. We take into account the effect of Pauli blocking, Fermi motion, Coulomb effect, renormalization of weak transition strengths in the nuclear medium in the case of the quasielastic reaction. The inelastic reaction leading to production of pions is calculated in a Δ-dominance model taking into account the renormalization of Δ properties in the nuclear medium and the final state interaction effects of the outgoing pions with the residual nucleus. We discuss the nuclear effects in the [Formula: see text] structure function in the deep inelastic neutrino(antineutrino) reaction using a relativistic framework to describe the nucleon spectral function in the nucleus.
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Pezzotti, Giuseppe. "Environmental Phase Stability of Next Generation Ceramic Composite for Hip Prostheses." Key Engineering Materials 309-311 (May 2006): 1223–26. http://dx.doi.org/10.4028/www.scientific.net/kem.309-311.1223.
Повний текст джерелаАнотація:
A hip-joint femoral head, made of alumina matrix composite, has been evaluated with respect to its surface degradation upon increasing elongation time in water vapor environment. A microscopic evaluation of surface degradation phenomena was obtained according to laser microprobe Raman and fluorescence spectroscopies. According to a confocal configuration of the optical probe, the spectroscopic assessments were performed in volumes limited to the very neighborhood of the material surface, thus minimizing the effect of the sub-surface, which was less affected by environmental degradation. Two main features were observed: (i) significant transformation of zirconia occurred in moist environment from the tetragonal to the monoclinic polymorph; such an environmentally induced phase transformation, conspicuously increased the fraction of monoclinic polymorph (i.e., ≅ 18 vol.% in average) already present in the as-received femoral head; (ii) the equilibrium residual stress field stored at the joint surface changed from a tensile field in the as-received material to a slightly compressive stress field after several hours aging in moist atmosphere and, after exposures >50 h to an increasingly tensile stress state. A residual stress field of tensile nature in the joint surface may trigger wear degradation in the femoral head in presence of microscopic (local) weight impingements due to micro-separation and third-body wear phenomena.
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Myint, Arthur Sun, Brice Thamphya, and Jean-Pierre Gerard. "Does non-TME surgery of rectal cancer compromise the chance of cure? Preliminary surgical salvage data from OPERA phase III randomized trial." Journal of Clinical Oncology 39, no. 3_suppl (January 20, 2021): 12. http://dx.doi.org/10.1200/jco.2021.39.3_suppl.12.
Повний текст джерелаАнотація:
12 Background: Non-operative modality (NOM) treatment of rectal cancer is gaining popularity as it avoids extirpative TME surgery and a stoma. OPERA trial was set up to evaluate the role of dose escalation using Contact X-ray brachytherapy [CXB] in improving the chance of organ preservation compared to the standard of care (EBCRT and TME surgery). We report on the preliminary surgical salvage data for treatment failures in the OPERA trial (NCT02505750). Methods: OPERA is a European phase 3 randomised trial between (Arm A- standard arm) EBCRT 45Gy/25/5weeks with oral capecitabine 825mg/m2 and EBRT boost of 9Gy/5/5 days randomised against (Arm B- experimental arm) EBCRT followed by CXB boost (90 Gy/3/4 weeks). Patients were assessed at 14, 20 and 24 weeks. Watch & wait policy was adopted for patients with cCR at 24 weeks after randomisation and surgery (TME or local excision) was offered for residual disease and also for local regrowth (recurrence) at a later date. Results: From July 2015 –June 2020, 148 patients were randomised of which 144 were evaluable (table). There were 71 patients in Arm A (standard) and 73 patients in Arm B (experimental). Median follow-up was 19 months (range 2-36 m). Overall clinical complete response (cCR) was observed in 103 out of 127 evaluable patients (81%) at 24 week in both arms (blinded). Surgery was carried out in 36/ 127 (28%) patients with suspected residual tumour. Further 13 patients had salvage surgery at a later date for local regrowth. At 19 months, 49/144 (34%) patients in total cohort had surgery. Local excision was carried out in 24 /49(49%) of which 3 proceeded to TME surgery due to R (1) or ypT2 adverse histology. TME surgery was carried out in 28/49 of which 8/28 (28.6%) had APER and 20/28(71.4%) had AR. In total, organ preservation (blinded) was achieved in 116/144 (80.5%) for the whole cohort. Kaplan Meier estimate of TME free survival is 76% at 19 months. Conclusions: Non-TME surgical treatment for cT2-cT3a-b rectal cancer is feasible in those who are fit and wish to avoid surgery (Watch & Wait). Those who needed surgery can be offered salvage surgery immediately for local residual disease or for local regrowth at a later date. Organ preservation of 80.5% (blinded) can be achieved without compromising their chance of cure. Clinical trial information: NCT02505750. [Table: see text]
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Yankovskii, A. P. "The Refined Model of Viscoelastic-Plastic Deformation of Reinforced Cylindrical Shells." PNRPU Mechanics Bulletin, no. 1 (December 15, 2020): 138–49. http://dx.doi.org/10.15593/perm.mech/2020.1.11.
Повний текст джерелаАнотація:
The paper formulates the initial-boundary-value problem of the viscoelastic-plastic bending behavior of cylindrical circular shells cross-reinforced along equidistant surfaces. The instant elastoplastic deformation of the shell composition components is described by the governing equations of the theory of plastic flow with isotropic hardening. The viscoelastic deformation of these materials is described by the defining relations of the Maxwell - Boltzmann model of body. The geometric nonlinearity of the problem is taken into account in the Karman approximation. The used system of two-dimensional resolving equations and the corresponding initial and boundary conditions make it possible to determine displacements and stress-strain state (including residual one) in materials of the composition of flexible cylindrical shells with varying degrees of accuracy. In this case, the weak resistance of the considered composite structures to transverse shears is taken into account. In the first approximation, the equations are used, the initial and boundary conditions correspond to the relations of the widely used non-classical Reddy theory. A numerical solution of the initial-boundary-value problem posed is constructed using an explicit step-by-step "cross" scheme. The elastoplastic and viscoelastic-plastic dynamic deformation of a relatively thin long circular cylindrical shell is investigated. The structure is rationally reinforced in the circumferential direction and is loaded with an internal pressure of an explosive type. It has been demonstrated that under intense short-term loading even of a relatively thin cylindrical reinforced shell by internal pressure, the traditional Reddy theory does not guarantee that the maximum residual deflection and the intensity of residual deformations of the components of the composition are accurate to within 10% compared to calculations performed by the refined theory. The difference in the results of the corresponding calculations increases with an increase in the relative thickness of the composite shell. It was found that after plastic deformation of a long reinforced cylindrical shell in its residual state, not only appear zones of edge effects, but also a local zone of an intense deformation located in the vicinity of the central section of the shell. The length of the local central zone is comparable with the length of the zones of edge effects. It is shown that the amplitude of the transverse vibrations of the reinforced shell in the vicinity of the initial moment of time significantly (by an order of magnitude) exceeds the value of the maximum modulus of the residual deflection. Therefore, the calculations performed in the framework of the theory of elastoplastic deformation of composition materials do not allow a very approximate determination of the magnitude of the residual displacements and the magnitude of the residual deformed state of the components of the composition of the cylindrical shell.
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Abdalla, Ahmed, Amr Aref, Amer Alame, Mohammed Barawi, Abdelkader Hawasl, and Adli Yakan. "Incidence and severity of postoperative complications following neoadjuvant therapy and full-thickness local excision for moderately advanced rectal cancer." Journal of Clinical Oncology 37, no. 15_suppl (May 20, 2019): e15167-e15167. http://dx.doi.org/10.1200/jco.2019.37.15_suppl.e15167.
Повний текст джерелаАнотація:
e15167 Background: Trans-anal full-thickness local excision (LE) for patients with moderately advanced rectal cancer (MARC) whose tumors respond well to neoadjuvant therapy, is one approach for organ preservation. Some authors call for abandoning this procedure because it causes frequent and severe complications. We aim to report our post-operative complications rate and severity following this procedure. Methods: This is a retrospective review of the complications observed in 10 patients who underwent LE at our center between May 2017-January 2019. Primary outcomes were the presence and nature of complications associated with the treatment course. Results: Five patients were treated according to Phase II trial and received three months of FOLFOX chemotherapy followed by concurrent chemo-RT. Five additional patients received only concurrent chemo-radiotherapy as they were treated off protocol. Radiation therapy (RT) dose ranged between 45-54 Gy and the interval between completion of RT and LE ranged between 6-15 weeks; median 11.5 weeks. Gross residual disease was resected with no margin in nine patients. The size of removed specimens ranged between 6.8-1.4cm; median 2.2 cm with a depth of resection of 1.5-0.4 cm; median .6 cm. Two patients had a very low residual gross abnormality and the surgical resection extended to the dentate line. Both patients experienced grade III complications of severe pain, infection and fistula formation. Of the remaining 8 patients with tumors located between 3-8 cm from the anal verge, two patients developed grade II complications requiring a short course of antibiotics and symptomatic treatment. In both cases, symptoms resolved within one week. Conclusions: Post-operative complications in this setting are not prohibitive if LE doesn’t extend to the dentate line and the resection is limited to only residual abnormality with no mucosal margin. A complete pathological response, confirmed by LE after neoadjuvant therapy provides valuable prognostic information and can influence the intensity and burden of future follow up. The risk of surgical complications is acceptable in view of these advantages. LE remains a viable option in pursuing organ preservation for MARC when complete remission is achieved by neoadjuvant therapy.
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Parding, Kajsa M., Beate G. Liepert, Laura M. Hinkelman, Thomas P. Ackerman, Knut-Frode Dagestad, and Jan Asle Olseth. "Influence of Synoptic Weather Patterns on Solar Irradiance Variability in Northern Europe." Journal of Climate 29, no. 11 (May 24, 2016): 4229–50. http://dx.doi.org/10.1175/jcli-d-15-0476.1.
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Abstract Observations have revealed strong variability of shortwave (SW) irradiance at Earth’s surface on decadal time scales, referred to as global dimming and brightening. Previous studies have attributed the dimming and brightening to changes in clouds and atmospheric aerosols. This study assesses the influence of atmospheric circulation on clouds and SW irradiance to separate the influence of “natural” SW variability from direct and, to some extent, indirect aerosol effects. The focus is on SW irradiance in northern Europe in summer and spring because there is little high-latitude SW irradiance during winter. As a measure of large-scale circulation the Grosswetterlagen (GWL) dataset, a daily classification of synoptic weather patterns, is used. Empirical models of normalized SW irradiance are constructed based on the GWL, relating the synoptic weather patterns to the local radiative climate. In summer, a temporary SW peak in the 1970s and subsequent dimming is linked to variations in the synoptic patterns over Scandinavia, possibly related to a northward shift in the North Atlantic storm track. In spring, a decrease of anticyclonic and increase of cyclonic weather patterns over northern Europe contributes to the dimming from the 1960s to 1990. At many sites, there is also a residual SW irradiance trend not explained by the GWL model: a weak nonsignificant residual dimming from the 1950s or 1960s to around 1990, followed by a statistically significant residual brightening. It is concluded that factors other than the large-scale circulation (e.g., decreasing aerosol emissions) also play an important role in northern Europe.
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Morales-Máximo, Mario, José Guadalupe Rutiaga-Quiñones, Omar Masera, and Víctor Manuel Ruiz-García. "Briquettes from Pinus spp. Residues: Energy Savings and Emissions Mitigation in the Rural Sector." Energies 15, no. 9 (May 7, 2022): 3419. http://dx.doi.org/10.3390/en15093419.
Повний текст джерелаАнотація:
This study analyzes the household energy needs of the indigenous community of San Francisco Pichátaro, Michoacán, Mexico, and the use of Pinus spp. wood residues for the production of briquettes. The energy and emission performances of wood briquettes were evaluated on the field and in the laboratory. On-field surveys and measurements show that most users combine the use of fuelwood and LPG for cooking and heating water, and 65% of people use fuelwood daily (40% of houses consumed more than 39 kg per week). The use of biomass waste is an energy option in rural communities and contributes to reducing firewood consumption and mitigating GHGs. Briquettes gasification to heat water reduces 74% of GHG emissions, increases the thermal efficiency by 30%, and reduces pollutant emissions of CO, CH4, and PM2.5, NMHC, EC, and OC by 50% to 75% compared to a three-stone fire. The use of briquettes on the Patsari stove showed energy savings of 12% and a 36% reduction in CO2e compared to the “U” type open fire. The briquettes could reduce the fuelwood consumption by 318 t/year. It is possible to produce briquettes at a cost similar to or cheaper than fuelwood and generate a local market (circular economy) with local benefits.
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Moore, Davi d. T., Anjali Ganjiwale, Hong Cheng, Heinrich Roder, William F. DeGrado та Joel S. Bennett. "Characterization of the Weak Interaction of C-Src with the β3 Cytoplasmic Tail". Blood 112, № 11 (16 листопада 2008): 2856. http://dx.doi.org/10.1182/blood.v112.11.2856.2856.
Повний текст джерелаАнотація:
Abstract Integrins are ubiquitously expressed α/β heterodimers that mediate cell-cell and cellextracellular matrix interactions. Integrins reside on the plasma membrane in a highly regulated dynamic equilibrium between an inactive resting state and an active ligand binding conformation. An essential feature of this equilibrium is the association and dissociation of integrin transmembrane (TM) and cytoplasmic domains. Thus, when integrins are inactive, the TM and cytoplasmic domains of their α and β subunits are in proximity; the domains separate when integrins assume their active conformations. Subsequent to ligand binding, integrins cluster to generate “outside-in” signals, believed to be initiated by the activation of integrin-associated c-Src and related kinases. The prototypic example of regulated integrin activation and outside-in signaling is the major platelet integrin αIIbβ3. We have employed exogenous αIIb TM binding peptides to stabilize the separated conformation of αIIbβ3 and better understand the link between integrin conformation and downstream signal transduction. These peptides activate αIIbβ3 independent of “inside-out” signal transduction and induce αIIbβ3-mediated platelet aggregation despite the presence of the inhibitory prostaglandin PGE1 or the metabolic inhibitors 2-deoxyglucose and NaN3. When platelets are stimulated by natural agonists such as ADP or thrombin, fibrinogen binds to αIIbβ3 after which the c-Src associated with the β3 cytoplasmic tail is activated. This results in a characteristic phosphotyrosine signal that can be detected by immunoblotting platelet lysates using phosphotyrosine-specific antibodies and can be inhibited by the αIIbβ3 antagonists abciximab and RGDS that inhibit fibrinogen binding and clustering of αIIbβ3 in the membrane. By contrast, exogenous αIIb TM binding peptides activate phosphotyrosine signaling in platelets in the presence of abciximab and RGDS. This clustering-independent signal transduction is both integrin- and Src-dependent as it is absent in β3 knockout mice and can be blocked by the Src inhibitors PP2 and dasatinib. To better understand how β3-associated Src kinases are activated, we investigated the interaction of c-Src with αIIbβ3 by NMR spectroscopy. It has been reported that the SH3 domain of c-Src interacts with the C-terminal three amino acids of β3, Arg-Gly-Thr. We synthesized short fragments of the β3 cytoplasmic domain containing this sequence and observed perturbations in the 15N-1H HSQC NMR spectrum of the c-Src SH3 domain. There were significant shifts in the backbone amide spectra for residues Arg19, Asp23, Leu24, Glu21, Thr20, Tyr55, and Asn36, as well as shifts in the spectra for the side chains of Trp42, Trp43, Asn37, and Asn59. Titration experiments revealed a dissociation constant of approximately 4 mM for β3 peptide binding to the SH3 domain. It is noteworthy that the perturbed residues are localized to one region of the SH3 domain and are located outside of the canonical polyproline binding groove, implying a new mode of SH3 interaction. Moreover, the weak interaction of c-Src with the β3 cytoplasmic domain is consistent with the high local concentrations of β3 and Src kinases at the platelet membrane and the dynamic nature of integrin protein-protein interactions. These results suggest that the cytoplasmic domain separation that accompanies αIIbβ3 activation may be sufficient to activate the Src kinases weakly associated with β3 cytoplasmic domain. Subsequent αIIbβ3 clustering and/or c-Src dissociation may then amplify the tyrosine phosphorylation signal to complete outside-in signaling.
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Farneti, Riccardo, Thomas L. Delworth, Anthony J. Rosati, Stephen M. Griffies, and Fanrong Zeng. "The Role of Mesoscale Eddies in the Rectification of the Southern Ocean Response to Climate Change." Journal of Physical Oceanography 40, no. 7 (July 1, 2010): 1539–57. http://dx.doi.org/10.1175/2010jpo4353.1.
Повний текст джерелаАнотація:
Abstract Simulations from a fine-resolution global coupled model, the Geophysical Fluid Dynamics Laboratory Climate Model, version 2.4 (CM2.4), are presented, and the results are compared with a coarse version of the same coupled model, CM2.1, under idealized climate change scenarios. A particular focus is given to the dynamical response of the Southern Ocean and the role played by the eddies—parameterized or permitted—in setting the residual circulation and meridional density structure. Compared to the case in which eddies are parameterized and consistent with recent observational and idealized modeling studies, the eddy-permitting integrations of CM2.4 show that eddy activity is greatly energized with increasing mechanical and buoyancy forcings, buffering the ocean to atmospheric changes, and the magnitude of the residual oceanic circulation response is thus greatly reduced. Although compensation is far from being perfect, changes in poleward eddy fluxes partially compensate for the enhanced equatorward Ekman transport, leading to weak modifications in local isopycnal slopes, transport by the Antarctic Circumpolar Current, and overturning circulation. Since the presence of active ocean eddy dynamics buffers the oceanic response to atmospheric changes, the associated atmospheric response to those reduced ocean changes is also weakened. Further, it is hypothesized that present numerical approaches for the parameterization of eddy-induced transports could be too restrictive and prevent coarse-resolution models from faithfully representing the eddy response to variability and change in the forcing fields.
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Gao, Yuan, Jingmang Xu, Ping Wang, and Yibin Liu. "Effect of Surface Hardening on Dynamic Frictional Rolling Contact Behavior and Degradation of Corrugated Rail." Shock and Vibration 2019 (August 25, 2019): 1–15. http://dx.doi.org/10.1155/2019/5493182.
Повний текст джерелаАнотація:
The present study was undertaken to evaluate the effect of surface hardening technology on dynamic frictional rolling contact behavior and degradation of corrugated rail in Shenzhen. Characteristic parameters such as length and depth of corrugation were analyzed by means of a continuous measurement method based on the corrugation analysis trolley. The explicit finite element method for material hardening characteristics and real contact geometry was adopted to set up the 3D transient FE model of wheel and rail, after which the value and distribution of stress/strain as well as contact solutions could be obtained during frictional contact, and then the Archard wear model and simplified wear superposition method are integrated as a numerical simulation tool for rail wear after hardening. The simulation results show that laminar plasma surface hardening technology can increase residual stress and shear stress in quenched zones, leading to local stress concentration at their boundaries; the plastic strain in the matrix material is higher than that in the quenched zones, while the strain concentration is mainly focused on the matrix material. The hardening can remarkably reduce the rail wear along the corrugation wave, and the wear depth of material with hardening technology is about 36% of that of nonhardening material. Laminar plasma surface hardening technology can therefore restrain the development of rail corrugation.
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Klocke, Fritz, Anton Shirobokov, Rafael Hild, Andreas Feuerhack, Daniel Trauth, and Patrick Mattfeld. "Friction and Wear Analysis of Deep Rolled and Vibrorolled Specimens in Lubricated Contact." Key Engineering Materials 767 (April 2018): 93–100. http://dx.doi.org/10.4028/www.scientific.net/kem.767.93.
Повний текст джерелаАнотація:
Deep rolling is an established mechanical surface treatment technology based on local plastic deformation of the surface layer. By these means, residual stresses, and strain hardening are induced into the surface layer as well as its surface structure is smoothed. Vibrorolling is a derivate technology of deep rolling characterized by sinusoidal rolling lanes. Due to process kinematics of vibrorolling the surface layer is incrementally deformed multiple times in different directions. As a result, a more intensive plastic deformation of the surface layer is achieved and potentially tribologically active surface structures are produced. To investigate and compare the effects of both surface treatment technologies on the tribological behavior of a processed component, a friction and wear analysis under lubricated conditions was conducted in this work. Friction and wear behavior of untreated, deep rolled, and vibrorolled specimens using a pin-on-cylinder tribometer was conducted. Hardness, roughness, and geometrical measurements of the wear traces were used to characterize the specimens. Additionally, qualitative assessments of the wear traces using scanning electron microscopy imaging were made. The measurements were performed before, during, and after the friction and wear analysis. Furthermore, contact forces between a tribometer pin and the workpiece were determined to analyze the development of contact shear stresses. Based on the conducted investigations, the effects of deep rolling and vibrorolling on the friction and wear behavior of the treated specimens are discussed and explanations for the observed phenomena are formulated in this work.
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Grasha, K., Q. H. Chen, A. J. Battisti, A. Acharyya, S. Ridolfo, E. Poehler, S. Mably, et al. "Metallicity, Ionization Parameter, and Pressure Variations of H ii Regions in the TYPHOON Spiral Galaxies: NGC 1566, NGC 2835, NGC 3521, NGC 5068, NGC 5236, and NGC 7793." Astrophysical Journal 929, no. 2 (April 1, 2022): 118. http://dx.doi.org/10.3847/1538-4357/ac5ab2.
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Abstract We present a spatially resolved H ii region study of the gas-phase metallicity, ionization parameter, and interstellar medium (ISM) pressure maps of six local star-forming and face-on spiral galaxies from the TYPHOON program. Self-consistent metallicity, ionization parameter, and pressure maps are calculated simultaneously through an iterative process to provide useful measures of the local chemical abundance and its relation to localized ISM properties. We constrain the presence of azimuthal variations in metallicity by measuring the residual metallicity offset Δ(O/H) after subtracting the linear fits to the radial metallicity profiles. We, however, find weak evidence of azimuthal variations in most of the galaxies, with small (mean 0.03 dex) scatter. The galaxies instead reveal that H ii regions with enhanced and reduced abundances are found distributed throughout the disk. While the spiral pattern plays a role in organizing the ISM, it alone does not establish the relatively uniform azimuthal variations we observe. Differences in the metal abundances are more likely driven by the strong correlations with the local physical conditions. We find a strong and positive correlation between the ionization parameter and the local abundances as measured by the relative metallicity offset Δ(O/H), indicating a tight relationship between local physical conditions and their localized enrichment of the ISM. Additionally, we demonstrate the impact of unresolved observations on the measured ISM properties by rebinning the data cubes to simulate low-resolution (1 kpc) observations, typical of large IFU surveys. We find that the ionization parameter and ISM pressure diagnostics are impacted by the loss of resolution such that their measured values are larger relative to the measured values on sub-H ii region scales.
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Bai, Peng, Jia Wang, Hui Zhao, Bo Li, Jingling Yang, Peiliang Li, and Tianyu Zhang. "Thermal Structure of Water Exchange at the Entrance of a Tide-Dominated Strait." Remote Sensing 14, no. 13 (June 25, 2022): 3053. http://dx.doi.org/10.3390/rs14133053.
Повний текст джерелаАнотація:
In summer, westward residual flow in the Qiongzhou Strait (QS) drives a water transport through the strait into the Beibu Gulf, playing a vital role in modifying the gulf-scale circulation. By utilizing multi-source observations, realistic simulations, as well as idealized modeling, the water exchange process at the western entrance of the QS was explored from the perspective of thermal structure. High-resolution satellite sea-surface temperature images captured an interesting thermal phenomenon in the studied region, i.e., a trident-shaped warm water tongue. Validations of numerical results suggested satisfactory model performance in reproducing the trident-shaped warm water tongue. Modeling results together with cruise observations indicates extremely weak stratification in the studied region, which is a result of local intense tidal mixing. The cold upwelling water developed at the eastern side of the strait arrived at the western entrance by the westward residual flow, and then encountered and communicated with the well-mixed warm gulf water there. The alternatively deep/shallow topography (sea trough/ridge) triggers spatial variability in tidal current intensity: stronger currents over the deep area with weaker flow above the shallow region leads to alternatively warm/cold thermal distribution in the cross-isobath direction. Further investigation demonstrates that, through modifying the circulation and regulating the intensity of upwelling on the eastern side of the QS, wind also makes a significant contribution to the thermal distribution at the western entrance of the QS.
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Shteingolts, Sergey A., Julia K. Voronina, Liliya F. Saifina, Marina M. Shulaeva, Vyacheslav E. Semenov, and Robert R. Fayzullin. "On the transfer of theoretical multipole parameters for restoring static electron density and revealing and treating atomic anharmonic motion. Features of chemical bonding in crystals of an isocyanuric acid derivative." Acta Crystallographica Section B Structural Science, Crystal Engineering and Materials 77, no. 6 (November 10, 2021): 871–91. http://dx.doi.org/10.1107/s2052520621009690.
Повний текст джерелаАнотація:
The crystal and electronic structure of an isocyanuric acid derivative was studied by high-resolution single-crystal X-ray diffraction within the Hansen–Coppens multipole formalism. The observed deformation electron density shows signs of thermal smearing. The experimental picture meaningfully assigned to the consequences of unmodelled anharmonic atomic motion. Straightforward simultaneous refinement of all parameters, including Gram–Charlier coefficients, resulted in more significant distortion of apparent static electron density, even though the residual density became significantly flatter and more featureless. Further, the method of transferring multipole parameters from the model refined against theoretical structure factors as an initial guess was employed, followed by the subsequent block refinement of Gram–Charlier coefficients and the other parameters. This procedure allowed us to appropriately distinguish static electron density from the contaminant smearing effects of insufficiently accounted atomic motion. In particular, some covalent bonds and the weak π...π interaction between isocyanurate moieties were studied via the mutual penetration of atomic-like kinetic and electrostatic potential φ-basins with complementary atomic ρ-basins. Further, local electronic temperature was applied as an advanced descriptor for both covalent bonds and noncovalent interactions. Total probability density function (PDF) of nuclear displacement showed virtually no negative regions close to and around the atomic nuclei. The distribution of anharmonic PDF to a certain extent matched the residual electron density from the multipole model before anharmonic refinement. No signs of disordering of the sulfonyl group hidden in the modelled anharmonic motion were found in the PDF.