scholarly journals DEM modeling of the one-dimensional compression of sands incorporating a statistical particle fragmentation scheme

2021 ◽  
Author(s):  
Mengmeng Wu ◽  
Jianfeng Wang ◽  
Budi Zhao
Keyword(s):  
Principal Component ◽  
Coefficient Matrix ◽  
Particle Crushing ◽  
Micro Computed Tomography ◽  
Particle Fragmentation ◽  
One To One ◽  
Ct Data ◽  
Specific Fragment ◽  
The One ◽  
Statistical Trends

This paper presents a novel framework of modeling crushable granular materials under mechanical loadings based on the discrete element method (DEM). The framework is featured with the construction of the one-to-one model in which every particle in a physical experiment has its own numerical twin and allows the modeling of irregular shaped fragments during the continuous breakage process. First, image processing techniques and spherical harmonic (SH) analysis were adopted, respectively, to segment and label particles and to construct a one-to-one model mathematically in DEM. Then, a particle crushing criterion based on the maximum inter-particle contact force was used to predict the crushing events, showing fitting results that agreed very well with a large number of single particle crushing tests. Next, a statistical approach for the generation of particle fragmentation modes of a given type of sand particles based on the principal component analysis (PCA) was proposed. The aim of the PCA was to analyze the statistical trends of the coefficient matrix, which was composed of the SH coefficients of all the particles involved in the analysis. Finally, a successful modeling of a particle crushing event was achieved by replacing the particle, which was judged by the crushing criterion to undergo crushing, with a few sub-particles chosen randomly from a specific fragment template constructed using the micro-computed tomography (micro-CT) data.

Spearman's Law of Diminishing Returns

2006 ◽  
Vol 27 (4) ◽  
pp. 199-207 ◽  
Author(s):  
Peter Hartmann
Keyword(s):  
Principal Axis ◽  
Age Groups ◽  
Principal Component ◽  
Longitudinal Survey ◽  
Male And Female ◽  
Two Samples ◽  
Diminishing Returns ◽  
The One ◽  
Armed Services ◽  
Principal Axis Factor

Spearman's Law of Diminishing Returns (SLODR) with regard to age was tested in two different databases from the National Longitudinal Survey of Youth. The first database consisted of 6,980 boys and girls aged 12–16 from the 1997 cohort ( NLSY 1997 ). The subjects were tested with a computer-administered adaptive format (CAT) of the Armed Services Vocational Aptitude Battery (ASVAB) consisting of 12 subtests. The second database consisted of 11,448 male and female subjects aged 15–24 from the 1979 cohort ( NLSY 1979 ). These subjects were tested with the older 10-subtest version of the ASVAB. The hypothesis was tested by dividing the sample into Young and Old age groups while keeping IQ fairly constant by a method similar to the one developed and employed by Deary et al. (1996) . The different age groups were subsequently factor-analyzed separately. The eigenvalue of the first principal component (PC1) and the first principal axis factor (PAF1), and the average intercorrelation of the subtests were used as estimates of the g saturation and compared across groups. There were no significant differences in the g saturation across age groups for any of the two samples, thereby pointing to no support for this aspect of Spearman's “Law of Diminishing Returns.”

Influence of Rim Run-Out on the Nonuniformity of Tire-Wheel Assemblies

1994 ◽  
Vol 22 (2) ◽  
pp. 99-120 ◽  
Author(s):  
T. B. Rhyne ◽  
R. Gall ◽  
L. Y. Chang
Keyword(s):  
Finite Element ◽  
Radial Force ◽  
Membrane Model ◽  
Model Experiments ◽  
Force Variation ◽  
One To One ◽  
The One

Abstract An analytical membrane model is used to study how wheel imperfections are converted into radial force variation of the tire-wheel assembly. This model indicates that the radial run-out of the rim generates run-out of the tire-wheel assembly at slightly less than the one to one ratio that was expected. Lateral run-out of the rim is found to generate radial run-out of the tire-wheel assembly at a ratio that is dependent on the tire design and the wheel width. Finite element studies of a production tire validate and quantify the results of the membrane model. Experiments using a specially constructed precision wheel demonstrate the behavior predicted by the models. Finally, a population of production tires and wheels show that the lateral run-out of the rims contribute a significant portion to the assembly radial force variation. These findings might be used to improve match-mounting results by taking lateral rim run-out into account.

Tree Rewriting Systems, Combinatory Weak Reduction Systems and Type Free Languages1

1982 ◽  
Vol 5 (3-4) ◽  
pp. 279-299
Author(s):  
Alberto Pettorossi
Keyword(s):  
Combinatory Logic ◽  
Rewriting Systems ◽  
Tree Transducers ◽  
Tree Languages ◽  
One To One ◽  
The One ◽  
Weak Reduction

In this paper we consider combinators as tree transducers: this approach is based on the one-to-one correspondence between terms of Combinatory Logic and trees, and on the fact that combinators may be considered as transformers of terms. Since combinators are terms themselves, we will deal with trees as objects to be transformed and tree transformers as well. Methods for defining and studying tree rewriting systems inside Combinatory Weak Reduction Systems and Weak Combinatory Logic are also analyzed and particular attention is devoted to the problem of finiteness and infinity of the generated tree languages (here defined). This implies the study of the termination of the rewriting process (i.e. reduction) for combinators.

scholarly journals Method for assessment of matching of total ankle joint endoprostheses based on CT data

2020 ◽  
Vol 6 (3) ◽  
pp. 396-397
Author(s):  
Heiner Martin ◽  
Josephine Wittmüß ◽  
Thomas Mittlmeier ◽  
Niels Grabow
Keyword(s):  
Cross Sections ◽  
Spline Functions ◽  
Moments Of Inertia ◽  
Cad System ◽  
Principal Moments Of Inertia ◽  
Principal Axes ◽  
Ct Data ◽  
The One ◽  
Relative Differences ◽  
Systemic Design

AbstractThe investigation of matching of endoprosthesis tibial components to the bone cross section is of interest for the manufacturer as well as for the surgeon. On the one hand, a systemic design of the prosthesis and the assortment is possible, on the other hand, a better matching implantation is enabled on the basis of experience of this study. CT sections were segmented manually using a CAD system and fitted by spline functions, then superseded with cross sections of the tibial component of a modified Hintermann H3 prosthesis. The principal moments of inertia, the direction of the principal axes and the area of the section were evaluated. Based on the relative differences of the principal moments of inertia, recommendations for application of the different prosthesis size and its selection with the surgery can be made.

scholarly journals A Micro-Computed Tomography Comparison of the Porosity in Additively Fabricated CuCr1 Alloy Parts Using Virgin and Surface-Modified Powders

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1995
Author(s):  
Mirko Sinico ◽  
Suraj Dinkar Jadhav ◽  
Ann Witvrouw ◽  
Kim Vanmeensel ◽  
Wim Dewulf
Keyword(s):  
High Energy ◽  
High Energy Density ◽  
Micro Ct ◽  
Micro Computed Tomography ◽  
Powder Bed ◽  
Metallurgical Defects ◽  
Ct Analysis ◽  
Ct Data ◽  
Surface Modified ◽  
Fusion Pores

Recently, the use of novel CuCr1 surface-modified powder for reliable laser powder-bed fusion (LPBF) manufacturing has been proposed, enabling a broader LPBF processing window and longer powder storage life. Nevertheless, virgin CuCr1 powder is also LPBF processable, on the condition that a high-energy density is employed. In this work, we compare two dense specimens produced from virgin and surface-modified CuCr1 powder. Furthermore, a third sample fabricated from surface-modified powder is characterized to understand an abnormal porosity content initially detected through Archimedes testing. Utilizing high-resolution micro-CT scans, the nature of the defects present in the different samples is revealed. Pores are analyzed in terms of size, morphology and spatial distribution. The micro-CT data reveal that the virgin CuCr1 dense specimen displays keyhole pores plus pit cavities spanning multiple layer thicknesses. On the other hand, the sample fabricated with the surface-modified CuCr1 powder mainly contains small and spherical equi-distributed metallurgical defects. Finally, the CT analysis of the third specimen reveals the presence of a W contamination, favoring lack-of-fusion pores between subsequent LPBF layers. The LPBF melting mode (keyhole or conductive), the properties of the material, and the potential presence of contaminants are connected to the different porosity types and discussed.

scholarly journals Detection and Localization for Multiple Stationary Human Targets Based on Cross-Correlation of Dual-Station SFCW Radars

2019 ◽  
Vol 11 (12) ◽  
pp. 1428 ◽  
Author(s):  
Yong Jia ◽  
Yong Guo ◽  
Chao Yan ◽  
Haoxuan Sheng ◽  
Guolong Cui ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Continuous Wave ◽  
Coefficient Matrix ◽  
Constant False Alarm Rate ◽  
Localization Algorithm ◽  
Cfar Detection ◽  
Stepped Frequency ◽  
The Cross ◽  
The One ◽  
Detection And Localization

This paper demonstrates the feasibility of detection and localization of multiple stationary human targets based on cross-correlation of the dual-station stepped-frequency continuous-wave (SFCW) radars. Firstly, a cross-correlation operation is performed on the preprocessed pulse signals of two SFCW radars at different locations to obtain the correlation coefficient matrix. Then, the constant false alarm rate (CFAR) detection is applied to extract the ranges between each target and the two radars, respectively, from the correlation matrix. Finally, the locations of human targets is calculated with the triangulation localization algorithm. This cross-correlation operation mainly brings about two advantages. On the one hand, the cross-correlation explores the correlation feature of target respiratory signals, which can effectively detect all targets with different signal intensities, avoiding the missed detection of weak targets. On the other hand, the pairing of two ranges between each target and two radars is implemented simultaneously with the cross-correlation. Experimental results verify the effectiveness of this algorithm.

In search of the perfect orthography

2005 ◽  
Vol 7 (2) ◽  
pp. 139-163 ◽  
Author(s):  
Richard L. Venezky
Keyword(s):  
Writing System ◽  
Writing Systems ◽  
International Phonetic Alphabet ◽  
Experienced Reader ◽  
Cultural Considerations ◽  
Advanced Stages ◽  
One To One ◽  
The One ◽  
Psychological Processing ◽  
The Ideal

Philologists, linguists, and educators have insisted for several centuries that the ideal orthography has a one-to-one correspondence between grapheme and phoneme. Others, however, have suggested deviations for such functions as distinguishing homophones, displaying popular alternative spellings, and retaining morpheme identity. If, indeed, the one-to-one ideal were accepted, the International Phonetic Alphabet should become the orthographic standard for all enlightened nations, yet the failure of even a single country to adopt it for practical writing suggests that other factors besides phonology are considered important for a writing system. Whatever the ideal orthography might be, the practical writing systems adopted upon this earth reflect linguistic, psychological, and cultural considerations. Knowingly or unknowingly, countries have adopted orthographies that favour either the early stages of learning to read or the advanced stages, that is, the experienced reader. The more a system tends towards a one-to-one relationship between graphemes and phonemes, the more it assists the new reader and the non-speaker of the language while the more it marks etymology and morphology, the more it favours the experienced reader. The study of psychological processing in reading demonstrates that human capacities for processing print are so powerful that complex patterns and irregularities pose only a small challenge. Orthographic regularity is extracted from lexical input and used to recognise words during reading. To understand how such a system develops, researchers should draw on the general mechanisms of perceptual learning.

Development of a Single-Code/Default Coding Strategy in Pigeons

2000 ◽  
Vol 11 (3) ◽  
pp. 261-264 ◽  
Author(s):  
Tricia S. Clement ◽  
Thomas R. Zentall
Keyword(s):  
Conditional Discrimination ◽  
The Other ◽  
Matching Accuracy ◽  
Efficient Coding ◽  
Coding Strategy ◽  
One To One ◽  
Retention Intervals ◽  
The Many ◽  
The One ◽  
Better Than

We tested the hypothesis that pigeons could use a cognitively efficient coding strategy by training them on a conditional discrimination (delayed symbolic matching) in which one alternative was correct following the presentation of one sample (one-to-one), whereas the other alternative was correct following the presentation of any one of four other samples (many-to-one). When retention intervals of different durations were inserted between the offset of the sample and the onset of the choice stimuli, divergent retention functions were found. With increasing retention interval, matching accuracy on trials involving any of the many-to-one samples was increasingly better than matching accuracy on trials involving the one-to-one sample. Furthermore, following this test, pigeons treated a novel sample as if it had been one of the many-to-one samples. The data suggest that rather than learning each of the five sample-comparison associations independently, the pigeons developed a cognitively efficient single-code/default coding strategy.

Intervention in Psychiatric Nursing; Process in the One-to-One Relationship

1970 ◽  
Vol 70 (11) ◽  
pp. 2450
Author(s):  
Ilse S. Wolff ◽  
Joyce Travelbee
Keyword(s):  
Psychiatric Nursing ◽  
Nursing Process ◽  
One To One ◽  
The One
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