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您的检索式：作者名="Matthew R.Hall"
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| 1 | Behaviour of granular matter under gravity-induced stress gradient:A two-dimensional numerical investigation显示文摘Gravity is the most important load source in mining and geotechnical engineering,which causes both the stress level and stress gradient inside geomaterials.Different from the stress level,the influence of gravity-induced stress gradient on the behaviour of the material is still unknown.An in-deep study on it will help to promote the understanding of material behaviour,especially for those cases related to unconventional gravity such as terrestrial ng physical modelling and extraterrestrial resource exploitation(g is the terrestrial gravitational acceleration).In this study,a high-order homogenization for granular materials is proposed at first,in which the stress gradient is drawn into the constitutive representation by adopting a representative volume element(RVE).The consolidation and shear strength behaviour of RVE are then investigated by performing numerical biaxial tests.The results show that all the compressibility,shear strength,shear stiffness,volumetric deformation,and critical state behaviour show a stress gradient dependence.A coupling between stress gradient,stress level,and material properties is also observed.These observations suggest that,besides the stress level,extra attention needs to be paid to material responses related to stress gradient during engineering practices. | Ruilin Li Guoqing Zhou Pin-Qiang Mo Matthew R.Hall Jun Chen Daqing Chen Shangyue Cai | 2021 | International Journal of Mining Science and Technology2021，31，3： | 2 |
| 2 | A platform for initial testing of multiple camouflage patterns显示文摘The human visual system is still an important factor in military warfare;military personnel receive training on effective search strategies,and camouflage that can effectively conceal objects and personnel is a key component of a successful integrated survivability strategy.Previous methods of camouflage assessment have,amongst others,used psychophysics to generate distinctiveness metrics.However,the population from which the human observers are drawn is often not well defined,or necessarily appropriate.In this experiment we designed a new platform for testing multiple patterns based on a camouflaged object detection task,and investigate whether trained military observers perform better than civilians.We use a two-alternative forced choice paradigm,with participants searching images of woodland for a replica military helmet displaying Olive Green,Multi Terrain Pattern,US Marine Pattern or,as a conspicuous control,UN Peacekeeper Blue.Our data show that there is no difference in detection performance between the two observer groups but that there are clear differences in the effectiveness of the different helmet colour patterns in a temperate woodland environment.We conclude that when tasks involve very short stimulus presentation times,task-specific training has little effect on the success of target detection and thus this paradigm is particularly suitable for robust estimates of camouflage efficacy. | Joanna R.Hall Olivia Matthews Timothy N.Volonakis Eric Liggins Karl P.Lymer Roland Baddeley Innes C.Cuthill Nicholas E.Scott-Samuel | 2021 | Defence Technology(防务技术)2021，17，6： | 0 |
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