Surface Microtextures of Slipping Zone Soil of Some Landslides in the Three Gorges Reservoir District and Their Significance

The mineral assemblage and content and surface microtextures of slipping zone soil of several landslides in the Three Gorges Reservoir District have been analyzed using the scanning electron microscope (SEM) and X-ray diffractometer (XRD). All the mineral assemblages are similar in these landslides. The main minerals are montmorillonite, illite, kaolinite, chlorite, quartz and feldspar. There are two kinds of surface microtexture in the slipping zone soil, i.e., linear scratches and arcuate scratches. Based on analyses of the changes of the microtextures, one can obtain information about the number, directions and stages of landslide movements. The authors have also studied the mechanism of landslide formation, evaluated the stability of landslides and revival possibility of ancient landslides and forecasted the activity of similar landslides in different districts. The surface microtexture features of stable landslides and mobile landslides are summarized and it is concluded that the existence of filamentous bacteria may result in or increase movements of landslides.

A preliminary study on microtextures，structures and mineralizing processes of hydrothermal chimneys in Mariana Trough

Microtextures and struetures of 9 hydrothermal chimneys sampled on the small spreading ridge Of the Mari ana Trough during SONNE Cruise 57 (SO57) and 69 (SO69) in 1988 and 1990 were studied by means of scanning electron microscope. The results reveal that the two types of chimneys from the Mariana Trough. the 'silicic chimneys' containing Fe sulfide and the pure 'silica chimneys' without sulfide, vary distinctly not only in mineral and chemical compositions, but also in microtextures and structures. The silicic chimneys generally show three major types of microtextures.The inside of the chimneys is dominated by holocrystalline or semicrystalline idiomorphic and hypidiomorphic granular textures and the outwall by amorphous colloidal texture. In some of the silicic chimneys relict texture is observed. However,the pure silica chimneys show chiefly amorphous colloidal texture from the inside to the outwall. Microstructurally. theinside of the silicic chimneys is dominated by a 'silica-covering' structure and a 'voidfilling' structure, and the outwall by a chain-like or three-dimentional chain-network structure built up by individual opal globules, whereas the pure silica chimneys are mainly three-dimentional chain-network and the dense silica bands in structure. These variations suggest that not only mineralizing conditions but also processes differ distinctly during the formation of the two types of chimneys, and that hydrothermal mineralization in the Mariana Trough shows a multistage or multieplsodical nature.

The Relationship between Microtexture Types and Indices of Physico-Mechanical Properties of Loess in China

The paper deals mainly with the relationship between the microtexture types and the indices of physicomechanical properties of loess. The results of study demonstrate that the study of microtextures of loess is of importance in the prediction and preliminary evaluation of engineering geological properties of loess in a region.

Mechanically driven assembly of biomimetic 2D-material microtextures with bioinspired multifunctionality

Nature provides a wealth of bio-inspiration for advanced material research.Assembling various nanomaterials into biomimetic microtextures with bioinspired functionalities has spurred increasing research interests and facilitated technological advances in various applications.In recent years,two-dimensional materials(2DMs)have emerged as important building block units in the biomimicry field due to their distinct chemical,physical,electrical,electrochemical,and catalytic properties.In this review article,various mechanically driven assembly approaches are summarized to fabricate various genealogies of biomimetic 2DM microtextures with bio-inspired multifunctionality.First,sequential deformation strategies are discussed to programmably construct higher dimensional 2DM microtextures,ranging from wrinkles/crumples(one-time deformation)to multiscale hierarchies(multiple deformations).Next,the current progress using higher dimensional 2DM microtextures to imitate different biological structures and/or induce bio-inspired multifunctionality is systematically summarized.Four showcases of bio-inspiration and biomimicry using different 2DM nanosheets are highlighted:(1)wrinkle patterns of an earthworm that spur the design of strain sensors with programmable working ranges and sensitivities,(2)wrinkle appearance of a Shar-Pei dog that motivates the fabrication of stretchable energy storage devices,(3)hierarchical scale textures of a desert lizard that inspire cation-induced gelation platforms for 2DM aerogels,and(4)wrinkle skin of an elephant that influences the development of 2DM protective skin for soft robots.Finally,challenges and future opportunities of adopting 2DM nanosheets to assemble biomimetic microstructures with synergistic functionalities are discussed.

The influence of microtexture on the formation mechanism of nodules in Zircaloy-4 alloy tube

Corrosion re sistance of Zircaloy-4 alloy tube in superheated steam at 673 K/10.3 MPa is anisotropic.A part of the surface undergoes uniform corrosion while the other suffers nodular corrosion.Narrow and wide nodules are observed after an exposure period of 3 and 30 days,respectively.A new matrix transformation method is established in order to study the formation mechanism of nodules in the cross-section(CS) of Zircaloy-4 alloy tube using the EBSD technique,while the CS perpendicular to axial direction(AD).The results reveal that the microtexture is a key factor behind the two types of corrosion.Furthermore,the oxide layers grow anisotropically over the corroded surface.A thick oxide layer forms over the nodular corrosion region on the grains with c-axis oriented in the range of 40° around tangential direction(TD),whereas a thin oxide layer over the uniform corrosion region is detected on the grains with c-axis oriented in the range of 68° around TD.In short,the anisotropic growth of oxide layer was caused by the change of microtexture of the Zr-4 alloy tube,and this anisotropic growth of oxide layer contributed to the nodules formation.

Critical rate capability barrier by the(001)microtexture of a singlecrystal cathode for long lifetime lithium-ion batteries

In practical pouch cell,LiNi0.5Mn0.3Co0.2O2/artificial graphite lithium ion battery using single-crystal LiNi0.5Mn0.3Co0.2O2(S-NMC532)as cathode can have excellent cycle performance.However,singlecrystal LiNi0.5Mn0.3Co0.2O2 inevitably suffers poor rate capability compared to the polycrystalline materials.Here,we systematically studied the relationship between microstructural characteristics and the practical rate performance,as well as explored the impedance change during the cycling process in the pouch cell.This work shows that the(001)plane microtexture of the electrode surface structure is a critical barrier for rate capability.Electron backscatter diffraction(EBSD),electrochemical impedance spectroscopy(EIS)and distribution of relaxation times(DRT)are conducted on the cathodes.These analyses allow to conclude on the influence of the(001)plane microtexture on the electrode surface,which illustrates a diffusion resistance of lithium ions,and then,leading a high interfacial resistance.Thus,this work confirms the main cause of the inferior rate capability of S-NMC532 and offers guidance for developing a battery with high rate and ultralong cycling life.

Microtextures on quartz grains from the Gulf of Mexico and the Mexican Pacific coastal sediments:Implications for sedimentary processes and depositional environment

Microtexture analyes on quartz from coastal sediments of the Gulf of Mexico and the Mexican Pacific Coast reveal 35 and 30 types of microtextures,respectively,which were grouped into mechanical,mechanical/chemical and chemical categories based on their mode of origin.Microtextures of chemical origin are rarer in the El Carrizal than in the Manzanillo beach sediments of the Mexican Pacific Coast.Microtextures of mechanical origin like straight and curved scratches,pits,broken edges,and V-shaped marks indicate high energy,fluvial to marine depositional environments.The scarcity to absence of chemical features suggest that the energy level was higher at the Mexican Pacific coast than on the Gulf of Mexico coast.V-shaped marks are common in the Gulf of Mexico sediments,whereas they are abundant in the quartz grains from the Mexican Pacific coast.Increased frequency and density of V-shaped marks are produced by exceedingly high wave velocity during storm events or tsunamis.Abundance of V-shaped marks with fresh surfaces of quartz grains from the Mexican Pacific coast indicate an extremely high-energy impact event.Many quartz grains from the El Carrizal beach of the Mexican Pacific coast have abundant closely spaced Vshaped marks with fewer fresh surfaces.Such high frequency of V-shaped marks is mainly linked to grain-tograin collision,typically associated with high-energy sub-aqueous conditions with a large volume of sedimentary particles in the water column that are produced during a tsunami or storm events.In contrast,many quartz grains from the Gulf of Mexico have large fresh surfaces with moderate percentages of V-shaped marks that might have been produced by high-energy waves with low sediment concentrations during storm events.

Analysis of Orange Peel Defect in St14 Steel Sheet by Electron Backscattered Diffraction (EBSD)

In this paper, the orange peel defect in the surface range of the st14 steel sheet has been investigated using the electron backscattered diffraction (EBSD) technique. It has been found that the orange peel defect in the st14 steel sheet was resulted from the local coarse grains which were produced during hot-rolling due to the critical deformation in dual-phase zone. During deep drawing, the coarse grains with {100}<001> microtexture can slip on the {112}<111> slip system to form bulging and yields orange peel defects, while the coarse grains with {112}<110> orientation do not form the defect as the Schmid factor of {112}<111> slip system in it equals zero.

Resolving the Routine Presence of Kyanite, Andalusite and Sillimanite across a Region using Foliation Intersection/Inflection Axes Preserved in Porphyroblasts, Petrographic Observations and Thermobarometry

Constraints from P-T pseudosections （MnNCKFMASH system）, foliation intersection/ inflection axes preserved in porphyroblasts （FIAs）, mineral assemblages and textural relationships for rocks containing all three Al2 SiO5 polymorphs indicate a kyanite→ andalusite→ sillimanite sequential formation at different times rather than stable coexistence at the Al2SiO5 triple point. All three Al2SiO5 polymorphs grew in the Chl, Bt, Ms, Grt, St, Pl and Crd bearing Ordovician Clayhole Schist in Balcooma, northeastern Australia separately along a looped P-T-t-D path that swaps from clockwise to anticlockwise in the tectono-metamorphic history of the region. Kyanite grew during crustal thickening in an Early Silurian Orogenic event followed by decompression/heating, andalusite and fibrolitic sillimanite growth during Early Devonian exhumation.

Hydrochemistry and sediment characteristics of polar periglacial lacustrine environments on Fisher Island and Broknes Peninsula,East Antarctica

Fisher Island and Broknes Peninsula in the Larsemann Hills constitute part of a polar lowland periglacial environment between marine and glacial ecosystems. The landscape is characterized by gently rolling hills and broad valleys interspersed with lakes formed in glacially scoured basins. We analyzed the physieochemical parameters and the ionic constituents of water samples from 10 lakes in each of these two locations. Our results showed considerable differences between the two regions and demon- strated the influence of lithology and processes including weathering, evaporation, and atmospheric precipitation. All major cations and anions in the lake waters showed positive correlations indicating balanced ionic concentrations. Unconsolidated sediments were sparsely distributed and scattered over glacial deposits, valley fills, and occasional moraine ridges. The type and rate of sedi- mentation was mainly controlled by surface run-off and aeolian influx. The sediment samples from lake beds and the catchment area on Fisher Island were immature and poorly to very poorly sorted, consisting of gravelly sand with negligible silt and finer fractions. Sediments had a polymodal grain size distribution with the two major populations lying between -2 and 1 phi and be- tween 0 and 1.5 phi. The sediments were lithic arenite to arkosic in composition and the microtextures imprinted over quartz grains were dominated by mechanical textures resulting from several stages of glacial crushing and grinding. The presence of deep disso- lution cavities, cryptocrystalline precipitation, and euhedral crystal growth signified the effect of chemical activity after the deposition of grains in the lacustrine environment.

Influence of Thin Water Film on Skid Resistance

Most of past researches on the skid resistance/road wetness relationship deal with thick water depths （〉 1 mm）. Questions remain as to the variation of skid resistance with thin water films and the transition between the dry state and the so-called ＂damp＂ or ＂humid＂ state at which the skid resistance drop can be as high as 30%-40%. This paper deals with a theoretical and experimental assessment of the friction-water depth relationship. The main objective is to estimate local water depths trapped between the tire and the road asperities and to define a so-called ＂critical＂ water depth which can be used to detect risky situations for road users. Tests are performed in laboratory. It was found that the friction-water depth curves have an inverse-S shape and present an initial constant-friction part before decreasing to a minimum value. A ＂critical＂ water depth, defined as the water depth above which the friction coefficient collapses significantly, is determined from surface texture on critical water depth is discussed. observed friction-water depth curves. Influence of test speed and

Determination and prediction of pavement skid resistance–connecting research and practice

Adequate pavement skid resistance is a key requirement for safe road operations.Unfortunately,the measurement and prediction of the skid resistance property of an in-service road pavement,or pavement mixture specimens in the laboratory,is a highly challenging process from both theoretical and practical points of view.For more than 60 years,owing to the lack of theoretical solutions to the complex tire-fluid-pavement interaction problem,the practice of pavement skid resistance determination and prediction has essentially been derived from experimental and field observed data.The rapid development of efficient numerical computational techniques and high-power computing facilities in the last two decades made it possible for researchers to numerically solve the tire-fluidpavement interaction problem.It enables the numerical evaluation and prediction of high-speed wet skid resistance,and the determination of the tire-pavement kinetic friction coefficient in the evaluation of low-speed skid resistance.This paper presents a state-of-the-art review of the research development of theoretical mechanistic approaches in the determination and prediction of pavement skid resistance.It covers the following main aspects of the subject matter:(i)mechanisms of skid resistance generation in dry,wetted(i.e.,damp),wet and flooded pavements;(ii)theoretical evaluation of pavement skid resistance in dry,wetted,wet and flooded states;(iii)theoretical approaches in pavement skid resistance prediction;and(iv)concepts of representing the skid resistance state of pavement.The capability of finite element simulation approach for wet skid resistance evaluation with good accuracy is explained.Also highlighted is the practical significance of the Concept of Skid Resistance State.Areas of practical applications of the concept,coupled with the simulation model,are introduced.They include applications in driving safety analysis,road safety design and control,design of paving mixtures,safety maintenance and management of pavements,and harmonization of skid resistance measurements and predictions.

Microstructural evolution in electroformed nickel shaped-charge liners with nano-sized grains undergone deformation at ultrahigh strain rate

Nickel shaped-charge liners with nano-sized grains were prepared by the electroforming technique, and the deformation at ultrahigh strain rate was performed by explosive detonation. The as-formed and post-deformed microstructures of electroformed nickel shaped-charge liners with nano-sized grains were observed by means of transmission electron microscopy, and the orientation distribution of the grains was analyzed by the electron backscattering pattern （EBSP） technique. The melting phenomenon in the jet fragment and the recovery and recrystallization in the slug after plastic deformation at ultrahigh-strain rate were observed in the ultrafine-grained nickel shaped-charge liners. The research evidence shows that dynamic recovery and recrystallization play an important role in plastic deformation at ultrahigh strain rate.

Fabrication and Wettable Investigation of Superhydrophobic Surface by Soft Lithography

The natural hydrophobicity of surfaces can be enhanced if they are microtextured due to air trapped in the structure, which provides the deposited drop with a composite surface made of solid and air on which it is rest. Here, a series of grating microstructure surfaces with different parameters have been designed and fabricated by a novel soft lithography. The water contact angles （WCA） on these rough surfaces are measured through optical contact angle meter. The results indicate that all the WCA on the surfaces with grating microstructures are up to 150~; WCA increases and the hydrophobic performance also enhances with the decrease of the ridge width under the other fixed parameter condition; Experimental data obtained basically consists with the Cassie＇s theoretical prediction. The effects of geometric parameters of the microstructures on wettability of the grating sufaces are investigated.

Extraction of Wind Stress from HF Radar Sea-Echo Doppler Spectra

This paper describes our preliminary results by using electron backscatter diffraction(EBSD) attachment in a scanning electron microscope. These studies revealed that the basal plane of 2H martensite originates from one {220} P plane of the parent phase, four variants A,B,C,D of a self accommodating plate group originate from various {220} P planes of the parent phase. Their orientation relationships can be determined by EBSD technique. The structural information provided by EBSD technique together with the composition information provided by energy dispersive X ray spectrometer leads to much convincible identification of micro area phases. By this method three phases were identified in as cast Al Cu Fe alloys with composition near that of icosahedral quasicrystal(IQC), namely IQC, λ Al 13 Fe 4 and β phases. Two types of grains were found in an interstitial free steel recrystallized at 750℃.Among them the flat grains possess γ fibre microtexture benifitial to the cold workability.

Oxidation Resistance of Isotropic Pitch-based Carbon Fiber

The oxidation resistance of isotropic pitch-based carbon fibers are sudied by thermogravimetric analysis,scanning electron microscope and mechanical propefties measure. The change of weight loss,microtextule and mechanical properties on condition of thermostatical oxidation and nonisothermal oxidation are separately mainly discussed.The results during isothermic oxidation at 316℃ showed that the weight loss of isotropic pitch-based carbon fiber increased and the strength, module rapidly decreased with prolongation of time, but the surface of carbon fiber is smoother and has not surface such as etching pits etc. The weight of isotropic pitch-based carbon fiber decreased more rapidly during the experiment of thermo-variable weight loss after 500℃ than before 500℃.

Microtextural Characteristics and Origin of Dolomites in the Tepearasi Formation, SW of Beysehir-Konya, Turkey

The Tepearasi Formation of the autochthonous Geyikdagi Group in the CentralTauride Belt, SE of Beysehir, is Dogger in age and consists dominantly of massive limestones andgreyish dolomites occurring within the middle to upper sections. The total thickness of thedolomitic levels ranges from 100-300 m and laterally extends 500-700 m. Three types of dolomite weredistinguished through petrographic analyses: homogeneous, mottled (saddle-crystalline) andjoint-filling dolomite, which were interpreted to have formed in two different stages, earlydiagenetic and late diagenetic. The homogeneous dolomite of the early diagenetic stage islight-coloured and monotonous-textured and shows the form of a dolosparite mosaic. The mottleddolomite formed in the late diagenetic stage is light- to dark-coloured and coarsely granularidiomorphic. The other type of late diagenetic dolomite, described as the joint-filling type,presents a crystal growth pattern from the joint walls towards the centre of the joint space. It isassociated with coarse calcite crystals as well as primary dolomite crystal clasts which were formedin the early diagenetic stage. In addition to these characteristics, cataclastic texture indicatingthe influence of tectonism is also observed. Microtexture-oriented scanning electron microscopy(SEM) studies indicate that mottled dolomites show zonal structures and contain secondarydissolution vugs. SEM studies also revealed the existence of some remains (calcite, clay etc.) injoint-filling dolomites. Analyses by energy dispersive spectrometry (EDS) indicate the existence ofclay minerals (likely to be illite) in the pores of dolomite. Isotope studies conducted to shedlight onto the origin of the dolomites of the Tepearasi Formation yielded the results of delta^18O=-2.48 to - 3.87 per thousand and delta^13C=0.93 to l.12 per thousand for the early diagenetichomogeneous dolomites. Mottled and joint-filling type dolomites of the late diagenetic stage, on theother hand, gave the results of delta^18O = -5.42 to -7.12 per thousand, and delta^13C= -2.29 and-5.70 respectively. X-Ray diffractometry (XRD) and energy dispersive analysis X-Ray (EDAX), atomicabsorption spectrometry (AAS) analyses, results of petrographic data, and delta^18O and delta^13Cvalues suggest that the early diagenetic dolomitization in the Tepearasi Formation occurred underthe control of hypersaline (rich in Mg) and fresh water mixing zone. The late diagenetic dolomitespartly developed under the control of tectonic thrusting.

Analysis and Characterization of Pore System and Grain Sizes of Carbonate Rocks from Southern Lebanon

Carbonate rocks are common in many parts of the world, including the Eastern Mediterranean, where they host significant groundwater supplies and are widely used as building and ornamental stones. The porosity of carbonate rocks plays a critical role in fluid storage and retrieval. The pore structure connectivity, in particular, controls many properties of geological formations, as well as the relationships between the properties of individual minerals and the bulk properties of the rock. To study the relationships between porosity, rock properties, pore structure, pore size, and their impact on reservoir characteristics, 46 carbonate rock samples were collected from four stratigraphic sections exposed near Sidon, South Lebanon. The studied carbonate rocks are related to marine deposits of different ages(e.g., Upper Cretaceous, Eocene, and Upper Miocene). In order to understand the pore connectivity, the MICP(mercury injection capillary pressure) technique was conducted on ten representative samples. Results from the SEM analysis indicate the dominance of very fine and fine pore sizes, with various categories ranging in diameter from 0.1 to10 μm. The MICP data revealed that the pore throat radii vary widely from 0.001 to 1.4 μm, and that all samples are dominated by micropore throats. The grain size analysis indicated that the studied rocks have significant amounts of silt-and clay-size grains with respect to the coarser ‘sand-size’ particles, suggesting a high proportion of microporosity. Obtained results, such as the poorly-sorted nature of grains, high microporosity, and the high percentage of micropore throats, justify the observed low mean hydraulic radius, the high entry pressure, and the very low permeability of the studied samples. These results suggest that the carbonate rocks near Sidon(south of Lebanon) are possibly classified as non-reservoir facies.

Glaciation-induced features or sediment gravity flows——An analytic review

For more than 150 years, geologic characteristics claimed to be evidence for pre-Pleistocene glaciations have been debated. Advancements in recent decades, in understanding features generated by mainly glacial and mass flow processes, are here reviewed. Detailed studies of data offered in support of prePleistocene glaciations have led to revisions that involve environments of mass movements. Similarities and differences between Quaternary glaciogenic and mass movement features are examined, to provide a more systematic methodology for analysing the origins of more ancient deposits. Analyses and evaluation of data are from a) Quaternary glaciogenic sediments, b) formations which have been assigned to pre-Pleistocene glaciations, and c) formations with comparable features associated with mass movements(and occasionally tectonics). Multiple proxies are assembled to develop correct interpretations of ancient strata. The aim is not per se to reinterpret specific formations and past climate changes, but to enable data to be evaluated using a broader and more inclusive conceptual framework.Regularly occurring pre-Pleistocene features interpreted to be glaciogenic, have often been shown to have few or no Quaternary glaciogenic equivalents. These same features commonly form by sediment gravity flows or other non-glacial processes, which may have led to misinterpretations of ancient deposits. These features include, for example, environmental affinity of fossils, grading, bedding, fabrics, size and appearance of erratics, polished and striated clasts and surfaces(“pavements”), dropstones, and surface microtextures.Recent decades of progress in research relating to glacial and sediment gravity flow processes have resulted in proposals by geologists, based on more detailed field data, more often of an origin by mass movements and tectonism than glaciation.The most coherent data of this review, i.e., appearances of features produced by glaciation, sediment gravity flows and a few other geological processes, are summarized in a Diamict Origin Table.

Detrital zircon U-Pb geochronology and geochemistry of the Riachuelos and Palma Sola beach sediments,Veracruz State,Gulf of Mexico:a new insight on palaeoenvironment

Zircons are abundant in the beach sediments.In this study,surface microtexture,mineralogy,bulk sediment geochemistry,trace element composition and U−Pb isotopic geochronology of detrital zircons collected from the Riachuelos and Palma Sola beach areas,southwestern Gulf of Mexico were performed to infer the sediment provenance and palaeoenvironment.The zircon microtexture was categorized as mechanically-and/or chemically-induced features.The weathering index values for the Riachuelos(~72−77)and Palma Sola(~71−74)beach sediments indicated moderate weathering of both of the two source areas.The major and trace element data of bulk sediments suggested passive margin settings for the two areas.The trace elemental ratios and chondrite-normalized rare earth element(REE)patterns of bulk sediments revealed that the sediments were likely sourced by felsic and intermediate igneous rocks.And the zircon Th/U ratios(mostly more than 0.2)and zircon REE patterns(with negative Eu and positive Ce anomalies)suggested a magmatic origin for both of the beach sediments from these two areas.Two distinct zircon age peaks respectively belonging to the Paleozoic and the Cenozoic were identified both in the Riachuelos and Palma Sola beach sediments.Zircon geochronology comparison research between the Riachuelos−Palma Sola beach sediments and potential source areas in SW Gulf of Mexico revealed that the source terrane supplied the Paleozoic zircons of this study was identified as the Mesa Central Province(MCP),and the Cenozoic zircons were transported from the nearby Eastern Alkaline Province(EAP).Moreover,although the Precambrian zircons were very few in the studied sediments,their geochronology and geochemistry results still could infer that they were contributed by the source terranes of Grenvillian igneous suites in the Oaxaca and the Chiapas Massif Complexes.