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Reliability analysis for mine blast performance based on delay type and firing time

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International Journal of mining Science and Technology 2018年第2期28卷 195-204页

作者： Silva Jhon Li Lifeng Gernand Jeremy m. Department of mining Engineering University of KentuckyLexingtonKY 40506USA The Pennsylvania State University PA 16802USA

mining blasts may be defined as the use of explosive charges in a controlled manner by following a tightly controlled timing sequence according to an assigned firing order. Changes of timing between charges may result in an altered firing order and failure of the blasting sequence, which can cause high vibration levels, poor fragmentation, and/or an undesirable rock mass movement direction. Despite the importance of timing in determining mine blast results, there exists a lack of methodologies or tools with which to assess performance of a complete blast based on delay type and timing sequence. This document applies reliability engineering principles to evaluate the performance of a mine blast. The analyses are based on test results of the accuracy and precision of electronic and pyrotechnic detonators for typical firing times used in a surface coal mine, but may be applied to a variety of mines and timing scenarios.

关键词： Blast Timing sequence Scatter Reliability Risk analysis monte Carlo simulation

Ageing Effect on Hardness and microstructure of Al-Zn-mg Alloys

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Journal of materials Science & Technology 2000年第3期16卷 319-322页

作者： m.Iqbal, m.A.Shaikh, m.Ahmad and K.A.Shoaib (Nuclear Physics Division, Pakistan Institute of Nuclear Science and Technology P.O.Nilore, Islamabad, Pakistan) Nuclear Physics Division Pakistan Institute of Nuclear Science and Technology P.O.Nilore Islamabad Pakistan

Experimental results of the investigation on the hardness of two Al-Zn-mg alloys [Al-10.0 Zn-4.0 mg and Al-8.5 Zn-3.0 mg (wt pct)] aged in the temperature range 60～310℃ for different intervals of time from 1/4 h to 168 h are presented. Both the alloys were found to show identical behaviour of hardness with ageing time. Alloy with higher Zn and mg content had higher hardness than the alloy with lower solute content. There were three ranges of temperature in which different types of precipitates formed and affected the hardness. Some of the grain boundaries were found to migrate and precipitate free zone has been observed.

关键词： Zn Ageing Effect on Hardness and microstructure of Al-Zn-mg Alloys Al

Numerical solutions of nonlinear fractional Wu-Zhang system for water surface versus three approximate schemes

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Journal of Ocean Engineering and Science 2019年第2期4卷 144-148页

作者： mostafa m.A.Khater Raghda A.m.Attia Dianchen Lu Department of mathematics Faculty of ScienceJiangsu UniversityChina Department of Basic Science Higher technological institute 10 th of Ramadan cityEgypt

This paper examines the effects of three distinct numerical schemes(Adomian Decomposition,quintic&septic Spline methods)to investigate semi-analytical and approximate solutions on Wu-Zhang(ZW)*** describes the(1+1)-dimensional dispersive long wave in two horizontal directions on shallow *** ZW model is one of the fractional nonlinear partial differential *** derivatives properties are employed to convert the nonlinear fractional partial differential equation into an ordinary differential equation with integer order so as to obtain the approximate solutions for this *** solutions obtained for each technique were compared to reveal their relationship to their characteristics illustrated under the suitable choice of the parameters *** obtained solutions showed the power,easiness,and effectiveness of these methods on nonlinear partial differential equations.

关键词： Fractional nonlinear Wu-Zhang system Conformable fractional derivatives Numerical schemes.

Regulation of Pollen Foraging Activity in Apis mellifera Africanized Honeybees Colonies

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Agricultural Sciences 2016年第6期7卷 335-340页

作者： Erica Gomes de Lima Simone Cristina Camargo Pedro da Rosa Santos Jose Washington Santos oliveira Vagner de Alencar Arnaut de Toledo Universidade Estadual de maringa Maringa Brazil Universidade Federal de Sergipe Sergipe Brazil Departamento de Zootecnia Universidade Estadual de Maringa Maringa Brazil

Efficient honey production requires knowledge about the behavior of the workers and the parameters that influence the strength of the colony. In this study, the objective was to analyze the interaction between the foraging behavior of worker honeybees and pollen storage levels in Africanized honeybees colonies. Colonies with low pollen storage increased pollen intake rates, but this value was 15% lower than colonies with high pollen storage, demonstrating a direct relationship between the pollen storage levels and foraging activity. The difference in pollen intake rates varied according to the number of foraging honeybees and pollen load collected by each individual. Under both high and low pollen storage, colonies returned pollen storage to initial level within 16 days, suggesting that honeybees regulate pollen storage levels around a homeostatic set point. Relationship between pollen storage levels and colony brood production was also found, indicating how alterations in the behavior of each individual can affect the strength of the colony.

关键词： Comb mapping Honeybee Nutrition management in Beekeeping Behavior

Repeatability of decision-making behaviour in male threespine stickleback Gasterosteus aculeatus： Effects of dummy vs. live stimuli

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Current Zoology 2011年第1期57卷 101-108页

作者： Teresa L. DZIEWECZYNSKI Lindsay m. FORRETTE Department of Psychology University of New England 11 Hills Beach Rd Biddeford ME 04005 USA

Individuals select from a number of behaviours when responding to various situations and the decisions they make may affect their fitness. The costs and benefits of these responses vary among individuals causing them to differ even in identical situations. One example of this type of situation is when territorial males encounter both a male and female simultaneously, gene- rating a trade-off that likely leads to individual differences due to differing costs of various actions among males. This situation commonly occurs in threespine stickleback, Gasterosteus aculeatus. However, for selection to act effectively, individuals must behave in a consistent manner and measuring repeatability can aid in understanding how selection may shape such trade-offs. males of this species exhibit consistent individual differences in their response to dummy males and females but it is unknown ff patterns are similar when feedback from the stimuli is present. To assess this, male threespine stickleback were tested with dummy and live male and female conspecifics, presented separately and simultaneously. While the same trends were found re- gardless of stimulus type, males were more aggressive towards the live conspecifics than to the dummies. Repeatability values were similar within a treatment regardless of whether live or dummy conspecifics were used, suggesting that individuals show the same level of consistency. This study adds to our understanding of consistent individual differences by demonstrating that feed- back may not affect responses to conflicting stimuli and that male threespine stickleback respond in a consistent manner to both dummy and live stimuli

关键词： Decision-making Stimulus efficacy Behavioural consistency Repeatability Threespine stickleback

Heavy metal concentrations in plants and soils at roadside locations and parks of urban Guangzhou

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Journal of Environmental Sciences 2006年第3期18卷 495-502页

作者： GUAN Dong-sheng m. R. Peart Department of Environmental Science Sun Yatsen University Guangzhou 510275 China Department of Geography University of Hong KongHong Kong China

Levels ofCu, Ni, Zn, Pb and Cr were measured in soils and trees in urban Guangzhou, China. Tree and soil samples were collected from the roadside, urban parks and a university campus. mean concentrations of Cu, Ni, Zn, Pb and Cr in tree leaves were 28.3, 7.7, 142.1, 23.4, and 195.1 mg/kg respectively. In a comparison of heavy metal concentrations in tree leaves between roads and park locations, only Pb concentrations were significantly higher in the former. Heavy metal concentrations were lower in the roots compared to leaves. It indicated that heavy metal pollution of trees is mainly from air pollution, For all top soil samples the mean concentrations of Cu, Ni, Zn, Pb and Cr were 24.3, 17.3, 121.5, 63.9 and 88.7 mg/kg, respectively. Heavy metal concentrations in roadside soils were higher and their coefficient of variation was higher than those in urban parks. Comparing heavy metal concentrations in trees and soil between urban Guangzhou and Hainan Island, China, Cu, Ni, Zn, Pb and Cr levels in soils and plants in urban Guangzhou were evidently affected by the human impact. However the heavy metal content in the soil compared to some international standards do not give cause for concern. Some observations on the implications of the data for environmental monitoring are made.

关键词： heavy metals roadside parks plants soil

Numerical Simulation of Wake-Field Acceleration Using an Eulerian Vlasov Code

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Communications in Computational Physics 2008年第8期4卷 703-718页

作者： m.Shoucri Institut de recherche d’Hydro-Quebec(IREQ) VarennesQuebecJ3X 1S1Canada

We study the generation of nonlinear plasma wake fields by intense laser pulses,using an Eulerian code for the numerical solution of the fully relativistic onedimensional(1D)Vlasov-maxwell *** examination of the phase-space of the distribution function allows to study without numerical noise aspects of the particle acceleration by the wake-field generated by intense laser pulses,in the very low density regions of the *** study the effect of the thermal spread on the existence of accelerated beams,and we compare between results obtained from a circularly polarized wave and a linearly polarized wave.

关键词： Eulerian code Vlasov-maxwell wake-field plasma

Seismic isolation effect of lined circular tunnels with damping treatments

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Earthquake Engineering and Engineering Vibration 2008年第3期7卷 305-319页

作者： Seyyed m. Hasheminejad Amir K. miri Acoustics Research Laboratory Department of Mechanical Engineering Iran University of Science and Technology Narmak Tehran 16844 Iran

The Havriliak-Negami model for dynamic viscoelastic material behavior and Biot＇s theory of poroelasticity are employed to develop an exact solution for three-dimensional scattering effect of harmonic plane P-SV waves from a circular cavity lined with a multilayered fluid-filled shell of infinite length containing viscoelastic damping materials and embedded within a fluid-saturated permeable surrounding soil medium. The analytical results are illustrated with numerical examples where the effects of liner/coating structural arrangement, viscoelastic material properties, liner-soil interface bonding condition, seismic excitation frequency, and angle of incidence on the induced dynamic stress concentrations are evaluated and discussed to obtain representative values of the parameters that characterize the system. It is demonstrated that incorporating viscoelastic damping materials with a low shear modulus in the constrained layer configuration is an efficient means of enhancing the overall seismic isolation performance, especially for near-normally incident seismic shear waves where the amplitudes of induced dynamic stresses may be reduced by up to one-third of those without isolation in a relatively wide frequency range. Some additional cases are considered and good agreements with solutions available in the literature are obtained.

关键词： underground tunnel permeable soil seismic wave scattering flee/constrained layer damping

Exact solutions of mHD second Stokes flow of generalized Burgers fluid

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Applied mathematics and mechanics(English Edition) 2015年第2期36卷 211-224页

作者： m.KHAN R.mALIK A.ANJUm Department of mathematics Quaid-i-Azam University

This work concerns with the exact solutions of magnetohydrodynamic（mHD）flow of generalized Burgers fluid describing the second Stokes problem. The modified Darcy law is taken into account. The related velocity distribution and shear stress are expressed as a combination of steady-state and transient solutions computed by means of integral transformations. The effects of various parameters on the flow field are investigated. The mHD flow results in reduction of velocity distribution and associated thickness of the boundary layer.

关键词： generalized Burgers fluid magnetohydrodynamic(mHD) flow porous medium exact solution