Evolution of pore systems in low-maturity oil shales during thermal upgrading--Quantified by dynamic SEM and machine learning

In-situ upgrading by heating is feasible for low-maturity shale oil,where the pore space dynamically evolves.We characterize this response for a heated substrate concurrently imaged by SEM.We systematically follow the evolution of pore quantity,size(length,width and cross-sectional area),orientation,shape(aspect ratio,roundness and solidity)and their anisotropy—interpreted by machine learning.Results indicate that heating generates new pores in both organic matter and inorganic minerals.However,the newly formed pores are smaller than the original pores and thus reduce average lengths and widths of the bedding-parallel pore system.Conversely,the average pore lengths and widths are increased in the bedding-perpendicular direction.Besides,heating increases the cross-sectional area of pores in low-maturity oil shales,where this growth tendency fluctuates at<300℃ but becomes steady at>300℃.In addition,the orientation and shape of the newly-formed heating-induced pores follow the habit of the original pores and follow the initial probability distributions of pore orientation and shape.Herein,limited anisotropy is detected in pore direction and shape,indicating similar modes of evolution both bedding-parallel and bedding-normal.We propose a straightforward but robust model to describe evolution of pore system in low-maturity oil shales during heating.

Manufacturing of SEM and TEM Samples for Oocyte

[ Objective] The research aimed to explore the manufacturing methods of scanning electron microscope （SEM） and transmission electron microscopy （TEM） for oocyte and provide technical support for related research. [ Method] Based on GV-and MII-stage oocytes, samples of SEM and TEM were prepared respectively, then ultrastructure changes were observed. [ Result] The results showed that the method needed few samples, keep intact cell morphology and can see clear ultrastructure. [Conclusion] The method is suitable for ultrastructural observation of oocyte.

Understanding the influence of petrographic parameters on strength of differently sized shale specimens using XRD and SEM

Ground failure is a major contributor to fatalities in underground mines in the US.Underground coal mines in the Northern Appalachian have weak roof rock composed of shale,which is prone to failure under high horizontal stress.Understanding the relationship among strength,specimen size and rock petrographic parameters is essential for developing an effective ground control plan.Size effect studies have found that rock strength varies with specimen size.This paper attempts to understand this strength variation using three specimen sizes(254-mm,508-mm,and 762-mm).The specimen strength was measured and the major petrographic parameters affecting the strength,namely grain size,grain shape,quartz content,clay content,etc.were analyzed using X-ray diffraction(XRD)and scanning electron microscopy(SEM).The petrographic parameters were then correlated with the strength of the three differently sized specimens.The results showed that 508-mm specimen had the lowest strength.Quartz content of the 508-mm specimen was lower than that of 254-mm and 762-mm specimens.Clay content and average grain size of the 508-mm specimen were higher than those of 254-mm and 762-mm specimens.These results clearly show that grain size,quartz content and clay content contribute to strength variation observed in differently sized shale specimens.

Microstructure of ferrospheres in fly ashes: SEM, EDX and ESEM analysis

Ferrospheres in fly ashes from a coal-fired power plant were extracted by a magnetic separation technique and their microstructure was studied by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and environmental scanning electron microscopy (ESEM). Ferrospheres in fly ashes show significant iron enrichment compared to their respective fly ashes. Iron oxides in ferrospheres mainly occur as minerals magnetite (Fe3O4) and hematite (α-Fe2O3), which are derived mainly from the decomposition and oxidation of iron-bearing minerals in coal during combustion. EDX data indicate that ferrospheres also contain Si, S, Al and Ca resulting from quartz, mullite, anhydrite and amorphous materials. A large percentage of ferrospheres are commonly 5～50 μm in size. The microstructure of ferrospheres includes smooth, polygonal, dendritic, granular and molten drop characteristics. SEM coupled with EDX provided fast and accurate results of the microstructure and chemical composition of ferrospheres, and helped us to assess environmental issues related to the disposal and utilization of fly ashes.

Investigation of meso-failure behaviors of Jinping marble using SEM with bending loading system

In th is study, th e m eso-failure m ech an ism an d fracture surface o f Jinping m arble w ere investigated bym ean s o f scanning electro n m icroscope （SEM） w ith ben d in g loading system and laser-scanner equipment. The Y antang an d B aishan m arbles specim ens from Jinping II hyd ro p o w er sta tio n w ere used. Testresu lts show th a t th e fracture to u g h n ess and m echanical behaviors o f Y antang m arble w ere basicallyh ig h er th a n th o se o f Baishan m arble. This is m ainly d u e to th e fact th a t Baishan m arble co n tain s a largep ercen tag e o f d o lom ite an d m in o r mica. Crack pro p ag atio n p a th and fracture m orphology in d icated th a tth e d irection o f ten sile stress has a significant effect on th e m echanical behaviors an d fracture toughnesso f B aishan m arble. For Yantang an d B aishan m arbles, a large n u m b e r o f m icrocracks a ro u n d th e m aincrack tip w ere observed w h e n th e directio n o f ten sile stress w as parallel to th e bed d in g plane.C onversely, few m icrocracks o ccurred w h e n th e directio n o f ten sile stress w as p erp en d icu lar to th ebed d in g plane. The presen ce o f a large n u m b e r o f m icrocracks a t th e m ain crack tip d ecreased th e globalfracture to u g h n ess o f m arble. The results o f th re e -p o in t ben d in g te sts show ed th a t th e average bearingcapacity o f intact m arble is 3.4 tim es th e notch ed m arble, b u t th e ductility p ro p e rty o f th e defectivem arble afte r p eak load is b e tte r th a n th a t o f th e intact m arble. H ence, large d efo rm atio n m ay beg en erated before failure o f in tact m arbles a t Jinping II h y d ro p o w er station. The fractal d im en sio n o ffracture surface w as also calculated by th e cube covering m eth o d . O bservational resu lt show ed th a t th elargest fractal dim en sio n o f Y antang m arble is cap tu red w h e n th e directio n o f ten sile stress is parallel toth e bedding plane. H ow ever, th e fractal d im en sio n o f fracture surface o f Yantang an d Baishan m arblesw ith ten sile stress vertical to th e bed d in g plane is relatively sm all. The fractal d im en sio n can also be usedto characterize th e ro ughness o f fracture surface o f rock m aterials.

Effect of Cu on Microstructures of Manganese Steel by EDXA and SEM

In order to investigate the distribution of Cu and Mg, and the effect of Cu on the microstructure of steels, manganese steels containing various Cu contents were annealed at 1260, 1100 and 1000℃, respectively, for I h and subsequently cooled to room temperature in the furnace to simulate the pre-rolling anneal. The results indicate that Cu is not microscopically segregated in the annealed steels. The scanning electron microscopy （SEM） observation shows that the main microstructure consist of ferrite and pearlite; the percentage of pearlite in the steels increases with increasing Cu content. The grain size reduces with the decrease of the annealing temperature. The results of energy dispersive X-ray analysis （EDXA） suggest that Cu content in pearlite is higher than that in ferrite, demonstrating that the microstructure-segregation of Cu occurred. However, the cast specimens show that Cu content in MnS and S-rich phases is high. In addition, Cu of 0.2%-0.4% could improve the distribution of MnS and S-rich inclusions. The optimal Cu content in steels and the optimal annealing temperature between 1100-1200℃ were determined.

Surface characteristics analysis of fractures induced by supercritical CO_(2)and water through three-dimensional scanning and scanning electron micrography

Morphology of hydraulic fracture surface has significant effects on oil and gas flow,proppant migration and fracture closure,which plays an important role in oil and gas fracturing stimulation.In this paper,we analyzed the fracture surface characteristics induced by supercritical carbon dioxide(SC-CO_(2))and water in open-hole and perforation completion conditions under triaxial stresses.A simple calculation method was proposed to quantitatively analyze the fracture surface area and roughness in macro-level based on three-dimensional(3D)scanning data.In micro-level,scanning electron micrograph(SEM)was used to analyze the features of fracture surface.The results showed that the surface area of the induced fracture increases with perforation angle for both SC-CO_(2)and water fracturing,and the surface area of SC-CO_(2)-induced fracture is 6.49%e58.57%larger than that of water-induced fracture.The fractal dimension and surface roughness of water-induced fractures increase with the increase in perforation angle,while those of SC-CO_(2)-induced fractures decrease with the increasing perforation angle.A considerable number of microcracks and particle peeling pits can be observed on SC-CO_(2)-induced fracture surface while there are more flat particle surfaces in water-induced fracture surface through SEM images,indicating that fractures tend to propagate along the boundary of the particle for SC-CO_(2)fracturing while water-induced fractures prefer to cut through particles.These findings are of great significance for analyzing fracture mechanism and evaluating fracturing stimulation performance.

Morphological variation and distribution of free neuromasts during half-smooth tongue sole Cynoglossus semilaevis ontogeny

This study was conducted to clarify the distribution and morphology of free neuromasts during the development of half-smooth tongue sole （Cynoglossus semilaevis） using scanning electron microscopy. During development, （1） the apical surface of free neuromasts changed in shape from a circle to a four-poiut star; （2） the external structure changed from being level with the epidermis to papilla-like above the level of the epidermis; （3） the neuromast cupula changed from cylindrical to blade-shaped; （4） the free neuromasts went from occurring singly to being in clusters of a few single organs; （5） the arrangement changed from a linear array to no discernable pattern; （6） there was a significant increase in the number of free neuromasts after metamorphosis. In adult C. semilaevis, free neuromasts were only observed on the abocular side of the head. Thus, there were more free neuromasts located on the abocular side of the head with a higher concentration around the anterior nostril and mouth, which may have a mechanical sensory function to help locate food as an adaptation to a benthic mode of life.

Elemental Analysis of Soil Phosphorus Neighborhoods Using SEM, Spectral Mapping and GIS

The utility of GIS （geographic information system） methods and spatial statistical analysis on spectral maps of sediment samples were examined. Detailed elemental maps are often constructed using energy dispersive X-ray techniques and SEM （scanning electron microscopy）. The elemental neighborhood associations of a single element, P （phosphorus）, were quantified at a magnification of 3,000 ×. For each of the 170,000 pixels on the images which displayed a strong P concentration, neighborhoods from 0.1μm^2 to 12 μm^2 were examined for associated elemental concentrations. PCA （principal component analysis） revealed two significant neighborhood types associated with P in samples of pH 4, and three neighborhood types at pH 8. These neighborhoods corresponded to Mg-P associations commonly found to be chemically prevalent in river sediments impacted by agricultural operations. Discriminant analysis showed that the greatest accuracy in predicting sample pH could be achieved by using a neighborhood size of 12 ~m2. Potassium at relatively large neighborhood sizes was the element most significant in predicting pH. While many of the chemical associations in close proximity to P could be predicted and explained through mineral solubility, spatial analysis provided some interesting insights into the structure of the samples. Results also indicted differences in the spatial scale associated with different processes.

Scanning Electron Microscopy Studies of YBa_2Cu_3O_(7-δ) Superconductors

Micrcostructures of bulk and thin film YBa_2Cu_3O_(7-δ) superconductors were studied by using scanning elec-tron microscopy (SEM). It was confirmed that viscous technique processed bulk YBa_2Cu_3O_(7-δ) has a homoge-neous microstructure across the pellet diameter. Concerning the thin film, it was found that 2 ￣H￣+ ion implanta-tion with a dose of 1× 10￣(12)cm￣(-2) at 50 keV does not cause microstructural change of the film at a micrometrelevel. Combined with previous studies by using high resolution transmission electron microscopy, it appearsthat the structural modification is at an atomic scale.

Effects of Functional Fish Organizations on the Fractal Characteristics of the Microstructure of Feces

Fish feces affect the structure and function of aquatic ecosystems,and they are affected by the functional fish organizations.In this research,Ctenopharyngodon idellus,Hypophthalmichthys molitrix,and Cyprinus carpio were selected to study the effects of different functional fish organizations on the fractal characteristics of fecal micro-structure by scanning electron microscopes(SEM),particles(pores)and cracks analysis system(PCAS).The results showed that fish feces pores mainly consisted of medium pores(cumulative pore number,97%)classified by the International Union of Pure and Applied Chemistry(IUPAC).The grain area fractal dimension D_(1) and the pore-number and pore-size fractal dimension D_(2) were 1.94-1.96 and 2.07-2.19,respectively.The distribution of fish feces pores was very close to the Sierpinski carpet structure,which is the basic fractal construction methods widely used to describe the fractal of pore surface distribution.D_(1)(1.96)and D_(2)(2.19)of Hypophthalmichthys molitrix were the maximum values of the three functional organizations.Combining with the habit of fish,it is inferred that the feces of H.molitrix,the finer the feed and the faster the swimming of fish,the higher the content of feces clay,the larger the fractal dimension of feces,the easier it is to decompose feces,and the high the content of nutrients and organic matter to release into the water.It is demined that fish functional organizations affected the fractal characteristics and the stability of fish feces in water.This study is helpful for further research on water quality prediction and the impact of functional fish organizations on the structure and function of the ecosystem.

Detection of Bisphenol A (BPA) in Plastic Bottles Using Vertical Cultivation at Various Temperatures

Polycarbonate plastics containing bisphenol A (BPA) used to manufacture drinking water bottles. Kurdistan region in northern Iraq is a developed area with increased pollution from plastic bottles. Trace amounts of BPA have been detected in bottled water samples. The absorption of BPA was measured with HPLC using a vertical cultivation system with Bulbs of the Allium Cepa plant planted in these plastic bottles with monitored growth. Vertical cultivation was found to have a low level of BPA in the plant cells, making it a safe cultivation method under specific climate conditions. The mean concentration of BPA in vertical cultivation is 0.19 ug/ml (3.8 ng for a 20 uL injection), and the Limit of Quantification (LOQ) is 0.63 ug/ml (12.7 ng for 20 uL injection). While Scanning Electron Microscope (SEM) shows that the concentrations are relatively low in water samples stored at room temperature compared to those exposed to direct sunlight (40°C) and water bottle samples stored at (-4°C), The correlation coefficients were found to be good (0.9992). SEM is used for plastic bottle samples stored at different temperatures. The images identify compound decay and explore the morphology of BPA in manufactured plastic materials.

Effectiveness of Sodium Silicate on the Corrosion Protection of AA7075-T6 Aluminium Alloy in Sodium Chloride Solution

The influence of sodium silicate on the corrosion behaviour of aluminium alloy 7075-T6 in 0.1 M sodium chloride solution was studied by open circuit potential (OCP) and electrochemical impedance spectroscopy (EIS) techniques. Scanning electron microscopy (SEM) was used to characterize the AA7075-T6 surface. Silicate can significantly reduce corrosion deterioration and the inhibition efficiency increases with the concentration of Na2SiO3. The corrosion inhibition mechanism involves the formation of a protective film over the alloy surface by adsorption of aluminosilicate anions from solution, as has also been suggested by others in literature.

Colonization Pattern of Azospirillum brasilense Yu62 on Maize Roots

Plasmid pVK1001 which carried the gfp gene of GFPmut2, a mutant of GFP, was introduced into Azospirillum brasilense Yu62 by electroporation. Maize seedlings were inoculated with the GFP-labelled baeteria and grown gnotobiotically in flask with semi-solid agar medium. Observations were performed with confocal laser scanning microscopy (CLSM) and electron microscopy, respectively, at 8 d and 12 d after inoculation. Confocal laser scanning microscopy showed that A. brasilense Yu62 could penetrate into the cortex tissue, colonizing in the intercellular spaces of the parenchyma cells of the cortex tissue. Transmission and scanning electron microscopy (TEM) showed that the majority of the bacteria colonized on the root surface and only a minority of them resided in the root interior.

Antibacterial activities and corrosion behavior of novel PEO/nanostructured ZrO_2 coating on Mg alloy

Plasma electrolytic oxidation（PEO） was developed as a bond coat for air plasma sprayed（APS） nanostructure ZrO2 as top coat to enhance the corrosion resistance and antibacterial activity of Mg alloy. Corrosion behavior and antibacterial activities of coated and uncoated samples were assessed by electrochemical tests and agar diffusion method toward Escherichia coli（E. coli） bacterial pathogens, respectively. The lowest corrosion current density and the highest charge transfer resistance, phase angle and impedance modulus were observed for PEO/nano-ZrO2 coated sample compared with those of PEO coated and bare Mg alloys. Nano-ZrO2 top coat which has completely sealed PEO bond coat is able to considerably delay aggressive ions transportation towards Mg alloy surface and significantly enhances corrosion resistance of Mg alloy in simulated body fluid（SBF） solution. Moreover, higher antibacterial activity was also observed in PEO/nano-ZrO2 coating against bacterial strains than that of the PEO coated and bare Mg alloys. This observation was attributed to the presence of ZrO2 nanoparticles which decelerate E. coli growth as a result of E. coli membranes.

Microstructure characteristics of cement-stabilized sandy soil using nanosilica

An experimental program was conducted to explore the impact of nanosilica on the microstructure and mechanical characteristics of cemented sandy soil.Cement agent included Portland cement type II.Cement content was 6% by weight of the sandy soil.Nanosilica was added in percentages of 0%,4%,8% and 12% by weight of cement.Cylindrical samples were prepared with relative density of 80% and optimum water content and cured for 7 d,28 d and 90 d.Microstructure characteristics of cementnanosilica-sand mixtures after 90 d of curing have been explored using atomic force microscopy(AFM),scanning electron microscopy(SEM) and X-ray diffraction(XRD) tests.Effects of curing time on microstructure properties of cemented sandy soil samples with 0% and 8% nanosilica have been investigated using SEM test.Unconfined compression test(for all curing times) and compaction test were also performed.The SEM and AFM tests results showed that nanosilica contributes to enhancement of cemented sandy soil through yielding denser,more uniform structure.The XRD test demonstrated that the inclusion of nanosilica in the cemented soil increases the intensity of the calcium silicate hydrate(CSH) peak and decreases the intensity of the calcium hydroxide(CH) peak.The results showed that adding optimum percentages of nanosilica to cement-stabilized sandy soil enhances its mechanical and microstructure properties.

Microstructural evolution and physico-chemical behavior of compacted clayey soil submitted to an alkaline plume

In the French concept of deep nuclear waste repositories,the galleries should be backfilled with excavated argillite after the site has been filled.Some additives like lime could be used to improve the mechanical characteristics of the argillite.After thousands of years,the degradation of the concrete lining of the galleries will generate an alkaline solution（pH value 12） that will diffuse through the backfill.This study presents the effect of a saturated Ca（OH）_2 solution circulation through lime-treated sample at 60 ℃ for 3,6 and 12 months,respectively.The effect of such circulation on the lime-treated Manois argillite（MA） was assessed by petrographical examination coupled to image analysis and scanning electron microscopy（SEM） equipped with energy dispersive X-ray（EDX） analyser of soil pieces.The objective of this study is to make the link among the mineralogical transformations,the textural and mechanical changes produced in the compacted clayey soil as a consequence of the alkaline solution circulation.

Morphological and toxicity characteristics of Pseudo-nitzschia pungens strain PP0201-01 isolated from the East China Sea

The morphology and toxicity of Pseudo-nitzschia strain PP0201-01, isolated near the estuary of Changjiang (Yangtze) River in Year 2002 and tentatively identified as Pseudo-nitzschia pungens, were studied. The strain was identified morphologically as P. pungens using scanning electronic microscope (SEM). The ana- lytical results of LC-PDA (liquid chromatography with photodiode array detector), LC-MS (liquid chromatogra- phy with mass detector), and the toxicity data from mouse bioassay, showed that no domoic acid was produced by the strain. However, the mechanism of domoic acid production by Pseudo-nitzschia species is complicated. More works are needed to assess the toxic species and to evaluate the potential risk of amnesic shellfish poison- ing (ASP) in China.

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.

Strength and compressibility behaviors of expansive soil treated with coffee husk ash

Various factors can affect the durability of roads, such as the strength of sub-grade, the quality of the subbase and base course, the environments and properties of the soil used. Particularly, roads built on expansive soil are susceptible to early damage due to the swelling and shrinkage characteristics of this kind of soil under changing moisture conditions. The most common technique used to improve the properties of problematic soil is stabilization with additives. Using waste materials to improve the properties of expansive soil is a recent trend in soil stabilization. This study deals with the treatment of expansive soil with coffee husk ash(CHA). Coffee husk is a by-product of coffee production, and CHA is the resulting ash after burning it. In this study, the bearing capacity and compressibility characteristics of expansive soil(specifically black cotton(BC) soil) stabilized with varying percentages of CHA(5%, 10%,15%, and 20%) are investigated. Then, scanning electron microscopy(SEM) and energy dispersive X-ray(EDX) were used to analyze the influence of CHA on surface morphology and chemical composition of the studied soil. The results showed that the soil treated with CHA is generally improved in terms of strength.Addition of 20% CHA increases the bearing capacity of the soil by three-fold. In addition, the morphological studies of the soil samples treated with 10% and 15% CHA indicated the formation of hydrated particles and cementitious compounds as a result of the reaction between the soil and CHA. This indicates the potential usage of CHA as a stabilization agent and subsequently, it can address the disposal and environmental concerns related to coffee husk.