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Influence of uncertainties: A focus on block volume and shape assessment for rockfall analysis

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第9期15卷 2250-2263页

作者： Gessica Umili Battista Taboni Anna Maria Ferrero Department of Earth Sciences University of Turinvia Valperga Caluso 3510125TurinItaly

Block size and shape depend on the state of fracturing of the rock mass and,consequently,on the geometrical features of the discontinuity sets(mainly orientation,spacing,and persistence).The development of non-contact surveying techniques applied to rock mass characterization offers significant advantages in terms of data numerosity,precision,and accuracy,allowing for performing a rigorous statistical analysis of the *** fact is particularly evident when dealing with rockfall phenomena:uncertainties in spacing and orientation data could significantly amplify the uncertainties connected with in situ block size distribution(IBSD),which represents a relation between each possible value of the volume and its probability of not being *** addition to volume,block shape can be considered as a derived parameter that suffers from *** attempts to model the possible trajectories of blocks considering their actual shape have been proposed,aiming to reproduce the effect on *** authors proposed analytical equations for calculating the expected value and variance of volume distributions,based on the geometrically correct equation for block volume in the case of three discontinuity *** quantify and discuss the effect of both volume and shape variability through a synthetic case ***,a fictitious rock mass with three discontinuity sets is assumed as the source of *** IBSDs obtained considering different spacing datasets are quantitatively compared,and the overall uncertainty effect is assessed,proving the correctness of the proposed ***,block shape distributions are obtained and compared,confirming the variability of shapes within the same ***,a comparison between trajectory simulations on the synthetic slope is reported,aiming to highlight the effects of the propagation of uncertainties to block volume and shape *** benefits of an approach that can quantify the uncertainties are discussed

关键词： Rockfall In situ block size distribution(IBSD) Block volume Shape Uncertainty

Free PSA performs better than total PSA in predicting prostate volume in Chinese men with PSA levels of 2.5–9.9 ng ml−1

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Asian Journal of Andrology 2023年第1期25卷 82-85页

作者： Ma-Ping Huang Ping Tang Cliff S Klein Xing-Hua Wei Wei Du Jin-Gao Fu Tian-Hai Huang Hui Chen Ke-Ji Xie Department of Urology The First Affiliated Hospital of Jinan UniversityGuangzhou 510630China Department of Urology Guangzhou First People's HospitalSouth China University of TechnologyGuangzhou 510180China Department of Urology Guangdong Provincial Work Injury Rehabilitation HospitalGuangzhou 510440China Department of Urology Guangdong Provincial Hospital of Integrated Traditional Chinese and Western MedicineFoshan 528253China Department of Urology Jiangmen Central HospitalAffiliated Jiangmen Hospital of Sun Yat-Sen UniversityJiangmen 529099China

This study investigated whether free prostate-specific antigen(fPSA)performs better than total PSA(tPSA)in predicting prostate volume(PV)in Chinese men with different PSA levels.A total of 5463 men with PSA levels of<10 ng ml^(−1) and without prostate cancer diagnosis were included in this *** were classified into four groups:PSA<2.5 ng ml^(−1),2.5–3.9 ng ml^(−1),4.0–9.9 ng ml^(−1),and 2.5–9.9 ng ml^(−1).Pearson/Spearman's correlation coefficient(r)and receiver operating characteristic(ROC)curves were used to evaluate the ability of tPSA and fPSA to predict *** correlation coefficient between tPSA and PV in the PSA<2.5 ng ml^(−1) cohort(r=0.422;P<0.001)was markedly higher than those of the cohorts with PSA levels of 2.5–3.9 ng ml^(−1),4.0–9.9 ng ml^(−1),and 2.5–9.9 ng ml^(−1)(r=0.114,0.167,and 0.264,respectively;all P≤0.001),while fPSA levels did not differ significantly among different PSA *** under ROC curve(AUC)analyses revealed that the performance of fPSA in predicting PV≥40 ml(AUC:0.694,0.714,and 0.727)was better than that of tPSA(AUC=0.545,0.561,and 0.611)in men with PSA levels of 2.5–3.9 ng ml^(−1),4.0–9.9 ng ml^(−1),and 2.5–9.9 ng ml^(−1),respectively,but not at PSA levels of<2.5 ng ml^(−1)(AUC:0.713 vs 0.720).These findings suggest that the relationship between tPSA and PV may vary with PSA level and that fPSA is more powerful at predicting PV only in the"gray zone"(PSA levels of 2.5–9.9 ng ml^(−1)),but its performance was similar to that of tPSA at PSA levels of<2.5 ng ml^(−1).

关键词： prostate cancer prostate-specific antigen prostatic hyperplasia volume

Higher volume growth rate is associated with development of worrisome features in patients with branch duct-intraductal papillary mucinous neoplasms

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World Journal of Clinical Cases 2022年第17期10卷 5667-5679页

作者： Tommaso Innocenti Ginevra Danti Erica Nicola Lynch Gabriele Dragoni Matteo Gottin Filippo Fedeli Daniele Palatresi Maria Rosa Biagini Stefano Milani Vittorio Miele Andrea Galli Gastroenterology Research Unit Department of Experimental and Clinical Biomedical Sciences"Mario Serio"University of FlorenceFlorence 50134Italy Emergency Radiology Unit Department of ServicesCareggi University HospitalFlorence 50134Italy Department of Medical Biotechnologies University of SienaSiena 53100Italy

BACKGROUND Branch duct-intraductal papillary mucinous neoplasms(BD-IPMNs)are the most common pancreatic cystic tumours and have a low risk of malignant *** guidelines only evaluate cyst diameter as an important risk factor but it is not always easy to measure,especially when comparing different *** the other side,cyst volume is a new parameter with low interobserver variability and is highly reproducible over *** To assess both diameter and volume growth rate of BD-IPMNs and evaluate their correlation with the development of malignant *** Computed tomography scans and magnetic resonance imaging exams were retrospectively *** diameter was measured on three planes,while the volume was calculated by segmentation:The volume of the entire cyst was determined by manually drawing a region of interest along the edge of the neoplasm on each consecutive slice covering the whole lesion;therefore,a threedimensional volume of interest was finally obtained with the calculated value expressed in cm^(3).Changes in size over time were *** development of worrisome features was *** We evaluated exams of 98 patients across a 40.5-mo median follow-up *** patients developed worrisome *** at baseline were significantly larger in patients who developed worrisome features(diameters P=0.0035,P=0.00652,P=0.00424;volume P=0.00222).volume growth rate was significantly higher in patients who developed worrisome features(1.12 cm^(3)/year vs 0 cm^(3)/year,P=0.0001);diameter growth rate was higher as well,but the difference did not always reach statistical *** but not diameter growth rate in the first year of follow-up was higher in patients who developed worrisome features(0.46 cm^(3)/year vs 0 cm^(3)/year,P=0.00634).CONCLUSION The measurement of baseline volume and its variation over time is a reliable tool for the follow-up of *** measurement could be a better tool than

关键词： Intraductal papillary mucinous neoplasms Cyst volume Growth Worrisome features Malignancies

Mechanism of expanding swept volume by nano-sized oil-displacement agent

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Petroleum Exploration and Development 2019年第5期46卷 991-997页

作者： LEI Qun LUO Jianhui PENG Baoliang WANG Xiaocong XIAO Peiwen WANG Pingmei HE Lipeng DING Bin GENG Xiangfei Research Institute of Petroleum Exploration&Development PetroChinaBeijing 100083China Key Laboratory of Nano Chemistry(KLNC) CNPCBeijing 100083China

The effect of expanding swept volume by iNanoW1.0 nanoparticles in ultra-low permeability core was studied by low-field nuclear magnetic resonance(LF-NMR)technology,and the mechanism of expanding swept volume was explained by oxygen spectrum nuclear magnetic resonance(17O-NMR)experiments and capillarity *** results of the LF-NMR experiment show that the nano-sized oil-displacement agent iNanoW1.0 could increase the swept volume by 10%-20%on the basis of conventional water flooding,making water molecules get into the low permeable region with small pores that conventional water flooding could not reach.17O-NMR technique and capillary analysis proved that iNanoW1.0 nanoparticles could weaken the association of hydrogen bonds between water molecules,effectively change the structure of water molecular clusters,and thus increasing the swept volume in the low permeable *** ability of weakening association of hydrogen bonds between water molecules of iNanoW1.0 nanoparticles increases with its mass fraction and tends to be stable after the mass fraction of 0.1%.

关键词： nanoparticles nano-sized oil-displacement agent water flooding swept volume water molecular hydrogen bonding capillary action

volume expansion rates of seismic landslides and influencing factors: A case study of the 2008 Wenchuan earthquake

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Journal of Mountain Science 2019年第8期16卷 1731-1742页

作者： MA Si-yuan XU Chong XU Xi-wei Key Laboratory of Active Tectonics and Volcano Institute of GeologyChina Earthquake AdministrationBeijing 100029China Institute of Crustal Dynamics China Earthquake AdministrationBeijing 100085China

When a big landside occurs, source material can change into loose deposit during its runout, causing the increase of the total landslide volume to some extent. Such changes can influence the quantification of seismic landslides. The objective of this paper was to study the volume expansion rate of landslides based on the data of 1417 co-seismic landslides triggered by the 2008 Wenchuan, China Mw 7.9 earthquake. We also analyzed the correlations between this rate and landslide geometric parameters(volume, height(H), length-width ratio(L/W), length-height ratio(L/H)), and environmental factors(peak ground acceleration(PGA), lithology, slope angle and aspect). The results show that the total source volume of the 1417 landslides is 1248 million m3, while the total volume of the deposit is 1501 million m3, which means the total volume expanding rate(Et) is 20.3% with the average volume expansion rate(Ea) 22.6%. The analysis indicates that volume expansion rate generally decreases with the increasing volume and height of landslides, while becoming larger with increasing L/H and L/W. Besides, the volume expansion rate is closely related to the landslide type and the volume scale of landslides. This study analyses volume change of co-seismic landslides deeply, permitting to help the correct quantification of the source volume and deposit volume of seismic landslide and a useful reference for the correct quantification of landslide volume.

关键词： Landslide volume volume expansion rate Wenchuan earthquake Influencing factors

volume of Singular Hyperbolic Sets

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Acta Mathematica Sinica,English Series 2021年第10期37卷 1507-1512页

作者： Dao Fei ZHANG Yun Tao ZANG Mathematics Institute University of WarwickCoventryCV47ALUK School of Mathematical Sciences East China Normal UniversityShanghai 200062P.R.C

Let X be a C^(1+)vector field on a compact Riemannian manifold M with dimension d≥***Λbe a transitive singular hypebolic set with positive *** show thatΛ=M andΛis a uniformly hyperbolic set without singularities.

关键词： Uniformly hyperbolic singular hyperbolic volume

Long-term Traffic volume Prediction Based on K-means Gaussian Interval Type-2 Fuzzy Sets

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IEEE/CAA Journal of Automatica Sinica 2019年第6期6卷 1344-1351页

作者： Runmei Li Yinfeng Huang Jian Wang the School of Electronic and Information Engineer ing Beijing Jiaotong University

This paper uses Gaussian interval type-2 fuzzy se theory on historical traffic volume data processing to obtain a 24-hour prediction of traffic volume with high precision. A K-means clustering method is used in this paper to get 5 minutes traffic volume variation as input data for the Gaussian interval type-2 fuzzy sets which can reflect the distribution of historical traffic volume in one statistical period. Moreover, the cluster with the largest collection of data obtained by K-means clustering method is calculated to get the key parameters of type-2 fuzzy sets, mean and standard deviation of the Gaussian membership *** the range of data as the input of Gaussian interval type-2 fuzzy sets leads to the range of traffic volume forecasting output with the ability of describing the possible range of the traffic volume as well as the traffic volume prediction data with high accuracy. The simulation results show that the average relative error is reduced to 8% based on the combined K-means Gaussian interval type-2 fuzzy sets forecasting method. The fluctuation range in terms of an upper and a lower forecasting traffic volume completely envelopes the actual traffic volume and reproduces the fluctuation range of traffic flow.

关键词： Gaussian interval type-2 fuzzy sets K-means clustering long-term prediction traffic volume traffic volume fluctuation range

Positron Spectroscopy of Free volume in Poly(vinylidene fluoride) after Helium Ions Irradiation

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Chinese Journal of Polymer Science 2019年第5期37卷 527-534页

作者： Jin-Zhe Lyu Roman Laptev Natalya Dubrova Division for Experimental Physics School of Nuclear Science & EngineeringNational Research Tomsk Polytechnic University

Free volume is an extremely important intrinsic defect in polymers. Structurally, free volume is the randomly distributed holes in the polymer molecular chain segments. In proton exchange membrane fuel cells, free volume is also the space needed for the directional conduction of protons. Irradiation by α particles to grafting sulfonated poly(vinylidene fluoride)(PVDF) is one of the methods to produce proton exchange membrane with good proton channel rate. Positron annihilation lifetime spectroscopy was used to study the free volume size at different absorbed dose levels from 0.13 MGy to 0.65 MGy. Measurement method of positron annihilation lifetime spectroscopy for PVDF based on ^(44) Ti positron source was developed. For low dose irradiation at 0.26 MGy, a decrease in free volume and practically unchanged crystallinity were observed. Further increase of absorbed dose range from 0.26 MGy to 0.39 MGy led to an increasing crystallinity with the same free volume level. For the absorbed dose from 0.39 MGy to 0.65 MGy, crystallinity was decreased but free volume remained almost constant.

关键词： Positron annihilation Free volume XRD Poly(vinylidene fluoride) Helium ions Connection Degradation

Modeling bubble column reactor with the volume of fluid approach:Comparison of surface tension models

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Chinese Journal of Chemical Engineering 2019年第11期27卷 2659-2665页

作者： Qi Liu Zhenghong Luo Department of Chemical Engineering College of Chemistry and Chemical EngineeringState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China

This work aims at comparing surface tension models in VOF(volume of Fluid) modeling and investigating the effects of gas distributor and gas velocity. Hydrodynamics of a continuous chain of bubbles inside a bubble column reactor was simulated. The grid independence study was first conducted and a grid size of 1.0 mm was adopted in order to minimize the computing time without compromising the accuracy of the results. The predictions were validated by comparing the experimental studies reported in the literature. It was found that all surface tension models can describe the bubble rise and bubble plume in a column with slight deviations.

关键词： Bubble column reactor Computational fluid dynamics volume of fluid method Surface tension models Gas distributor