Application of the needle penetration test to a calcarenite, Maastricht, the Netherlands     

D.J.M. Ngan-Tillard  W. Verwaal  A. Mulder  H.K. Engin  R. Ulusay 《Engineering Geology》2011,(3):214

In this paper, first, the needle penetrometer test is briefly presented and experience gained, mainly in Japan and Turkey, with a model manufactured in Japan is reviewed. Second, the needle penetrometer test is used successfully to distinguish qualitatively carbonate sands from very weak and weak calcarenites in borehole cores recovered for cut-and-cover tunnel projects in Maastricht. Third, the relation between UCS and needle penetration resistance (NPR) for the Maastrichtian limestones is further analyzed. Needle penetration tests are conducted with the help of a loading frame. Results suggest that there is a statistically significant relationship between the UCS and NPR, that leaves however to high predictive uncertainty. During testing, very high compressive and shear stresses develop under the needle and stresses normal to the needle shaft increase. Microscopic observations show the extent of grain crushing and compaction ahead and around the needle. Nevertheless, resistance to needle penetration and UCS values are somehow related. The needle penetrometer is recommended as an index test rather than a way to determine accurately the UCS of the Maastrichtian limestones.  相似文献   

Oceanic thermohaline intrusions: theory     

Barry Ruddick  Oliver Kerr 《Progress in Oceanography》2003,56(3-4):483

This is a review of theories governing growth and evolution of thermohaline intrusive motions. We discuss theories based on eddy coefficients and salt finger flux ratios and also on molecular Fickian diffusion, drawing relationships and parallels where possible. We discuss linear theories of various physical configurations, effects of rotation and shear, and nonlinear theories. A key requirement for such theories to become quantitatively correct is the development and field testing of relationships between double-diffusive fluxes and average vertical gradients of temperature and salinity. While we have some ideas about the functional dependencies and rough observational constraints on the magnitudes of such flux/gradient relationships, many questions will not be answered until usable ‘flux laws’ exist. Furthermore, numerical experiments on double-diffusive intrusions are currently feasible, but will have more quantitative meaning when fluxes are parameterised with such laws. We conclude that more work needs to be done in at least two areas. Firstly, tests of linear theory against observations should continue, particularly to discover the extent to which linear theories actually explain the genesis of intrusions. Secondly, theoretical studies are needed on the nonlinear effects that control the evolution and finite amplitude state of intrusions, since these determine the lateral fluxes of salt, heat, and momentum.  相似文献   

青石斑外周血细胞显微结构的观察     

黄思基  曹伏君  李长玲 《海洋通报》2006,25(6):30-36

报道了青石斑外周血细胞的显微结构,血涂片经过wright染色液染色,可区分出:红血细胞、血栓细胞、嗜中性粒细胞、单核细胞、淋巴细胞等5种血细胞,未发现嗜碱性粒细胞、嗜酸性粒细胞。白血细胞中,血栓细胞体积最小,单核细胞体积最大;在数量上,血栓细胞最多,淋巴细胞次之,单核细胞和嗜中性粒细胞则较少。青石斑的淋巴细胞可分为以下三种类型:大淋巴细胞、中淋巴细胞和小淋巴细胞。此外,在外周血液中还观察到少量未成熟的红血细胞和嗜中性粒细胞,幼稚型、成熟型和功能衰退型以及三者之间过渡类型的嗜中性白细胞皆可见到。偶尔可见正在分裂的红血细胞及单核细胞,提示红血细胞及白血细胞的部分种类也可在外周血直接分裂。  相似文献   

铬铁磨球的研究及应用     

张兰英 《广东海洋大学学报》1996,(1)

综述了铬铁磨球研究方面的最新成果。并对铬铁磨球的生产工艺要点、组织性能特点及应用效果进行了重点讨论。  相似文献   

Micromorphology of landslide soil——Case study on the Jibazi landslide in Yunyang in the Three Gorges Region, China   总被引：2，自引：1，他引：1  

HE Yurong CUI Peng LIAO Chaolin ZHANG Baohua ZHAO Yu 《山地科学学报》2006,3(2):147-157

Introduction The studies on landslides in the Three Gorges Region were conducted, e.g., those on affecting factors and forming mechanism of landslide (YIN Kunlong et al. 1998, DENG Qinglu et al. 2000, CHEN Yongbo et al. 2003, XU Qiang et al. 2003), on ris…  相似文献   

Theoretical aspects and interpretation of thermal measurements concerning the subsurface investigation of a cometary nucleus     

Thomas Keller  Tilman Spohn 《Planetary and Space Science》2002,50(9):929-937

Part of the lander payload for the comet rendezvous mission Rosetta is the thermal probe multi-purpose sensors for surface and subsurface science (MUPUS). In this paper, we discuss the relationship of the expected MUPUS data to structural and textural parameters of the near-surface layers of the cometary nucleus. Such properties could be crucial parameters concerning the formation and evolution of the nucleus. Thus, we calculate the thermal conductivity of a porous material in terms of microstructural parameters, using a geometrical model with a solid matrix, a surrounding pore space and a distinct contact area between different particles. We include the possibility that a significant amount of heat may be transported by pore filling vapour in addition to heat conducted via the matrix. Furthermore, we consider that the heat is transmitted through only a fraction of the grains and these are organized into a chain-like structure. These chains—and not the single grains—should be regarded as the basic unit of structure. Applying our model to measured thermal conductivities of porous water ice, we interpret the material in terms of microparameters and estimate the effective size of the contact area and the effective pore radius. The results are in good agreement with our knowledge of the prepared samples. Contrary, we can also show that popular models used in cometary research do not fit with laboratory data at all.  相似文献   

勒氏笛鲷外周血细胞显微结构的观察     

李长玲  曹伏君  刘楚吾  陈刚 《广东海洋大学学报》2001,21(3):5-9

报道了勒氏笛鲷外周血细胞的显微结构,血涂片经过Wright染色液染色,可区分出红血细胞、血栓细胞、嗜中性粒细胞、单核细胞、淋巴细胞等五种血细胞,没有发现嗜碱性粒细胞、嗜酸性粒细胞.白血细胞中,血栓细胞体积最小,单核细胞体积最大;血栓细胞数目最多,淋巴细胞和单核细胞数目最少;淋巴细胞有大小两种类型大淋巴细胞和小淋巴细胞.此外,在外周血液中还观察到少量未成熟的红细胞和嗜中性粒细胞,偶而可见正在分裂的红细胞,提示红细胞也可在外周血直接分裂.  相似文献   

Microstructure Investigation in Unsaturated Soils: A Review with Special Attention to Contribution of Mercury Intrusion Porosimetry and Environmental Scanning Electron Microscopy   总被引：5，自引：1，他引：4  

Enrique Romero  Paul H. Simms 《Geotechnical and Geological Engineering》2008,26(6):705-727

With the advent of modern microstructural testing techniques and microstructure based constitutive models the microstructural characterisation of soils is gaining prominence. This paper reviews the history of microstructure investigation in unsaturated soils and discusses the engineering significance of this research to date. After a brief overview of the main microstructural techniques, the paper focuses on the evaluation of the current state of use and the development of two widely used techniques to study the microstructure of partially saturated soils, namely mercury intrusion porosimetry and the environmental scanning electron microscopy. The details of these techniques, their advantages and limitations, are first covered, followed by the presentation of selected test results. These results highlight the use of these techniques for understanding different hydro-mechanical behavioural features observed at macroscopic scale. Specifically, the paper shows the use of these techniques to explore the fundamental properties of water retention characteristics, water permeability, and micro and macrostructural interactions along different hydro-mechanical paths.  相似文献   

Quantitative characterization of plastic deformation of zircon and geological implications   总被引：1，自引：1，他引：0  

Steven M. Reddy  Nicholas E. Timms  Wolfgang Pantleon  Patrick Trimby 《Contributions to Mineralogy and Petrology》2007,153(6):625-645

The deformation-related microstructure of an Indian Ocean zircon hosted in a gabbro deformed at amphibolite grade has been quantified by electron backscatter diffraction. Orientation mapping reveals progressive variations in intragrain crystallographic orientations that accommodate 20° of misorientation in the zircon crystal. These variations are manifested by discrete low-angle (<4°) boundaries that separate domains recording no resolvable orientation variation. The progressive nature of orientation change is documented by crystallographic pole figures which show systematic small circle distributions, and disorientation axes associated with 0.5–4° disorientation angles, which lie parallel to rational low index crystallographic axes. In the most distorted part of the grain (area A), this is the [100] crystal direction. A quaternion analysis of orientation correlations confirms the [100] rotation axis inferred by stereographic inspection, and reveals subtle orientation variations related to the local boundary structure. Microstructural characteristics and orientation data are consistent with the low-angle boundaries having a tilt boundary geometry with dislocation line [100]. This tilt boundary is most likely to have formed by accumulation of edge dislocations associated with a 〈001〉{100} slip system. Analysis of the energy associated with these dislocations suggest they are energetically more favorable than TEM verified 〈010〉{100} slip. Analysis of minor boundaries in area A indicates deformation by either (001) edge, or [100](100) and [001](100) screw dislocations. In other parts of the grain, cross slip on (111), and (112) planes seems likely. These data provide the first detailed microstructural analysis of naturally deformed zircon and indicate ductile crystal-plastic deformation of zircon by the formation and migration of dislocations into low-angle boundaries. Minimum estimates of dislocation density in the low-angle boundaries are of the order of ∼3.10¹⁰ cm⁻². This value is sufficiently high to have a marked effect on the geochemical behavior of zircon, via enhanced bulk diffusion and increased dissolution rates. Therefore, crystal plasticity in zircon may have significant implications for the interpretation of radiometric ages, isotopic discordance and trace element mobility during high-grade metamorphism and melting of the crust.  相似文献   

Magnetic fabrics and microstructures of the Jurassic Shah-Kuh granite pluton (Lut Block, Eastern Iran) and geodynamic inference     

D. Esmaeily  J.L. Bouchez  R. Siqueira 《Tectonophysics》2007,439(1-4):149-170

The Jurassic Shah-Kuh granite pluton was emplaced in the northeastern part of the Lut Block (Eastern Iran) while this block was a part of the active margin under which the Tethys ocean, that separated Arabia from Central Iran, was subducting. Since this time, the Lut Block has rotated and migrated northward up to its present position. This structural study of the Shah-Kuh aims at strengthening the evidence of its original geodynamical location. Thanks to a systematic collection of oriented samples in the field, well-defined fabric and microstructural patterns were deduced from magnetic fabric measurements and optical microscopy observations. The overall magnetic fabric of the pluton yields vertical, north–south striking foliations and shallow lineations plunging to the north. The corresponding microstructures attest to their formation in the magmatic stage, i.e. during emplacement. Subsequent deformation, characterized by (sub)mylonitic microstructures, has modified the original fabric into a northwest and locally a west–northwest trend inside a two kilometre-wide corridor. This corridor reflects the trace of a sinistral shear zone that offsets the previous north–south magmatic pattern of the pluton. The latter magmatic pattern is proposed to result from the shear component of strain that was parallel to the ancient active margin during pluton emplacement, as a result of strain partitioning, a situation frequently documented at convergent margins. Sinistral shear along an  E–W directed south-facing active margin, assuming a northeastward slip vector for the Tethys ocean during the Jurassic, and accepting a  150° counterclockwise rotation of the Lut Block after emplacement of the Shah-Kuh pluton, best explains both the magmatic and the solid-state lineation patterns.  相似文献