Crushed Samples Research Articles

Preparation of a spinel LiMn2O4 single crystal film from a MnO wafer

Spinel LiMn2O4 is a very promising material for positive electrodes in a wide range of Li-ion battery applications due to its lower cost and more environmental friendliness than any other electrode materials. Although the bulk properties of LiMn2O4 have been studied intensively, there have been few reports about the structure and properties of LiMn2O4 surfaces in spite of the importance of solid/electrolyte interfaces. This is caused by the difficulty in preparing LiMn2O4 samples with accessible flat surfaces suitable for atomistic observations. To address this, we have successfully prepared a single crystalline LiMn2O4 film with an atomically flat surface by solid-state reaction from a MnO wafer with LiOH.H2O powder. X-ray diffraction (XRD) reveals the single crystalline growth of LiMn2O4 films depending on the orientation of a MnO wafer. Atomic force microscopy observations revealed that a LiMn2O4 (111) film has an atomically flat surface with steps of a {111} interlayer height. Electron energy-loss spectroscopy (EELS) study of the (111) film revealed that the sample consists of Li, Mn3+ and Mn4+ with a composition similar to LiMn2O4. The (111) film sample is also investigated by cyclic voltammetry and galvanostatic experiments, revealing that a crushed powder sample from the film has electrochemical activity as usual positive electrode material.

Swelling Measurements of a Low Rank Coal in Supercritical CO<sub>2</sub>

Coal swelling in the presence of water as well as CO2 is a well-known phenomenon, and these may affect the permeability of coal. Quantifying swelling effects is becoming an important issue to verify the suitability of particular coal seams for CO2-enhanced coal bed methane recovery projects. In this report, coal swelling experiments using a visualization method in the CO2 supercritical conditions were conducted on crushed coal samples. The measurement apparatus was designed specifically for the present swelling experiment using a visualization method. Crushed coal samples were used instead of block coal samples to shorten equilibrium time and to solve the problem of limited availability of core coal samples. Dry and wet coal samples were used in the experiments because there is relatively limited information about how the swelling of coal by CO2 is affected by water saturation. Moreover, some coal seams are saturated with water in initial reservoir conditions. The maximum volumetric swelling was around 3% at 10 MPa for dry samples and almost half that at the same pressure for wet samples. The wet samples showed lower volumetric swelling than dry ones because the wet coal samples were already swollen by water. Experimental results obtained for swelling were comparable with other reports. Our visualization method using crushed samples has advantages in terms of sample preparation and experimental execution compared with the other methods used to measure coal swelling using block samples.

Impact of Supercritical CO2/Water Interaction on the Caprock Nanoporous Structure

In the context of CO2 geological storage, storage capacity and safety are two aspects to be evaluated in order to ensure the efficiency of this operation. The safety of this technique is primarily related to the conservation of the intrinsic properties of the caprock (stratigraphic trapping), which are controlled by the porous structure. This paper focuses on the assessment of the impact caused by the CO2/water interaction on the porous nanostructure. A suspension of crushed rock samples and synthetic water was reacted with supercritical CO2 at 84 bar and 53 ̊C under static conditions over a 2-month period. At the end of the experiment, the solid and liquid phases were collected in order to analyze the porous structure of the rock and water chemistry. Over short time periods, the results show a slight increase of the microporous and mesoporous volumes due to the rapid dissolution of calcite compared to the slower dissolution of aluminosilicates.

Nanopore-Structure Analysis and Permeability Predictions for a Tight Gas Siltstone Reservoir by Use of Low-Pressure Adsorption and Mercury-Intrusion Techniques

Summary The pore structure of unconventional gas reservoirs, despite having a significant impact on hydrocarbon storage and transport, has historically been difficult to characterize because of a wide pore-size distribution (PSD), with a significant pore volume (PV) in the nanopore range. A variety of methods is typically required to characterize the full pore spectrum, with each individual technique limited to a certain pore size range. In this work, we investigate the use of nondestructive, low-pressure adsorption methods, in particular low-pressure N2 adsorption analysis, to infer pore shape and to determine PSDs of a tight gas silt-stone reservoir in western Canada. Unlike previous studies, core-plug samples, not crushed samples, are used for isotherm analysis, allowing an undisturbed pore structure (i.e., uncrushed) to be analyzed. Furthermore, the core plugs used for isotherm analysis are subsamples (end pieces) of cores for which mercury-injection capillary pressure (MICP) and permeability measurements were previously performed, allowing a more direct comparison with these techniques. PSDs, determined from two isotherm interpretation methods [Barrett-Joyner-Halenda (BJH) theory and density functional theory (DFT)], are in reasonable agreement with MICP data for the portion of the PSD sampled by both. The pore geometry is interpreted as slot-shaped, as inferred from isotherm hysteresis loop shape, the agreement between adsorption- and MICP-derived dominant pore sizes, scanning-electron-microscope (SEM) imaging, and the character of measured permeability stress dependence. Although correlations between inorganic composition and total organic carbon (TOC) and between dominant pore-throat size and permeability are weak, the sample with the lowest illite clay and TOC content has the largest dominant pore-throat size and highest permeability, as estimated from MICP. The presence of stress relief-induced microfractures, however, appears to affect laboratory-derived (pressure-decay and pulse-decay) estimates of permeability for some samples, even after application of confining pressure. On the basis of the premise of slot-shaped pore geometry, fractured rock models (matchstick and cube) were used to predict absolute permeability, by use of dominant pore-throat size from MICP/adsorption analysis and porosity measured under confining pressure. The predictions are reasonable, although permeability is mostly overpredicted for samples that are unaffected by stress-release fractures. The conceptual model used to justify the application of these models is slot pores at grain boundaries or between organic matter and framework grains.

Advances in Measuring Permeability Address Shortcomings of Crushed-Rock Technique

This article, written by Editorial Manager Adam Wilson, contains highlights of paper SPE 152257, ’Advances in Measurement Standards and Flow Properties Measurements for Tight Rocks Such as Shales,’ S. Sinha, SPE, E.M. Braun, SPE, Q.R. Passey, SPE, S.A. Leonardi, SPE, A.C. Wood III, T. Zirkle, SPE, J.A. Boros, SPE, and R.A. Kudva, SPE, ExxonMobil Upstream Research, prepared for the 2012 SPE/EAGE European Unconventional Resources Conference and Exhibition, Vienna, Austria, 20-22 March. The paper has not been peer reviewed. The most commonly used industry method for measuring permeability is the Gas Research Institute (GRI) technique or its variants, which involve the use of crushed samples. The accuracy of such techniques, however, is questionable because of a number of inadequacies, such as the absence of reservoir overburden stress while conducting these measurements. In addition to the questionable accuracy of crushed-rock techniques, studies have indicated that there is significant variability in results reported by different laboratories that use crushed-rock techniques to measure permeability on shale samples. The complete paper presents a robust steady-state technique for measuring permeability on intact tight-rock samples under reservoir overburden stress. These standards can be used to calibrate any permeability-measurement apparatus used on intact tight-rock samples, such as shales, to enable delivery of consistent results across different laboratories. Introduction For low-permeability reservoirs such as shales, the GRI method is popular because of the relatively quick times associated with the measurements as a result of the increased surface area available and because of the perception that measurements on intact low-permeability plug samples by use of well-established methods such as steady state or pulse decay could take such long times that it would make such measurements impractical. However, using crushed rock for measuring permeability has a number of inadequacies, resulting in skepticism associated with the accuracy of such measurements. Perhaps the most serious drawback of the crushed-rock method for measuring permeability, as presented in a number of studies, is the wide variability in results reported by different vendors, with results that could differ by as much as three orders of magnitude. Shortcomings of GRI Technique of Measuring Permeability The GRI, or crushed-rock, technique for measuring permeability is a relatively fast method for measuring permeability on low-permeability samples, but it has the following shortcomings. Absence of Overburden Stress. The GRI technique is implemented on crushed rock samples, and, therefore, these measurements are not conducted at reservoir overburden stress. Ignoring the effect of overburden stress while measuring the permeability could lead to significant discrepancy between permeability measured in the laboratory and in-situ permeability.

Correction to Klinkenberg slip theory for gas flow in nano-capillaries

Using a lattice Boltzmann (coarse grain) simulation of gas dynamics we show that the apparent permeability values of nano-scale capillaries could be significantly higher than those predicted by the Klinkenberg slip theory. The difference is due to kinetic effects of gas molecules that have gone through inelastic collisions with the capillary walls on those molecules that make up the bulk fluid in the capillary. The kinetic energy that the bouncing-back molecules have and the associated momentum carried to the bulk fluid is not a trivial matter in capillaries with diameter, h , less than 100 nm. Momentum carried by bouncing-back molecules amplifies the velocity profile developing across the diameter of the capillary. In a sense, it is not only the molecules interacting with the capillary wall that slip but also those interacting with the bulk fluid, i.e., double‐slip. The double-slip effect is shown using measured permeability data of two crushed nano-porous samples, Pyrophyllite, and three different shale samples at varying pore pressures. Using the simulation results, we propose a modification to the Klinkenberg equation. Our new double-slip Klinkenberg equation includes a characteristic length scale ( L Ke ) that is proportional to the kinetic energy per capillary cross-sectional area of the bouncing-back molecules by the capillary walls. The new length scale of the molecular kinetic effects in nano-capillaries is larger than the mean free path of the molecules. The double-slip Klinkenberg equation reduces to the classical equation for slip flow in large capillaries, i.e., h/ L Ke >> 1, and converges to the absolute permeability value at high pressure.

The determination of some physical characteristics of different particle sizes in soils with reflection spectroscopy

The main objective of this study is to evaluate the ability of visible near-infrared reflectance spectroscopy (VNIRS) to predict diverse soil properties in grinding different particular size effect. In this study, 60 soil samples were collected from the fields include different soil ordo (Entisols, Inceptisols, Vertisols and Mollisols) in Isparta (Atabey) district Crushed samples were subjected into five different mesh sizes (4.76-2.00, 2.00-1.00, 1.00-0.50, 0.5-0.25 and <0.25 mm, respectively). Each soil samples were scanned with a visible near-infrared spectrometer, with a spectral range of 350 to 2500 nm, at five different particular sizes. The spectral reflectances were used to predict some physical properties of the soil (texture, field capacity and wilting point) using partial least squares (PLS) regression. PLS analysis was used to develop calibration models between smoothed-first derivative 6-nm-spaced spectral reflectance data and soil physical analysis measured clay, silt, sand, field capacity and wilting point. The results showed that while soils need to be crushed to pass through 0.25 mm sieve in order to determine wilting point and amount of clay, mesh size was found non-significant in determining sand, silt and field capacaity and the results obtained from the reflectance values taken from field samplings proved to be satisfactory. Key words: Texture, field capacity, wilting point, visible near-infrared reflectance spectroscopy (VNIRS).

Laboratory investigation of triple marking the parasitoid Gonatocerus ashmeadi with a fluorescent dye and two animal proteins

AbstractGonatocerus ashmeadi Girault (Hymenoptera: Mymaridae), a parasitoid of Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) (glassy‐winged sharpshooter), was used as a model insect to investigate triple marking a minute hymenopteran for potential use for monitoring dispersal patterns of natural enemies in the field. The triple mark contained egg albumin in chicken eggs, casein in bovine milk, and SARDI yellow fluorescent dye. Three application treatments of the triple mark were investigated: (1) a wet topical treatment, (2) a dry residue treatment, and (3) untreated control. The presence of albumin and casein protein marks were detected by an anti‐albumin and anti‐casein enzyme‐linked immunosorbent assays (ELISA) using both ‘soaked’ and ‘crushed’ specimens. Of the topically treated parasitoids, yellow dye, casein, and albumin were detected on 88, 69, and 21% of the crushed samples, respectively. The yellow dye and casein (tested with crush ELISA) were the most efficient marking methods, detecting up to 29% more marked G. ashmeadi. Yellow dye resulted in zero false positives in the untreated control. The percentage of false positives for casein (tested with crush ELISA) was 1.3; however, this was reduced to 0% when a double‐marking system using any two of the three marks (yellow dye, casein, and albumin) were used to mark parasitoids. This double‐mark system resulted in 65% of parasitoids being successfully marked in the topical treatment over the duration of the study. For casein, crush ELISA was 26% more sensitive and 24% more accurate than soak ELISA for detecting this mark. Yellow dye, albumin, and casein (tested with crush ELISA) were retained on marked parasitoids for the entire duration of the 11‐day study. Parasitoids self‐marked with yellow dye, albumin (tested with soak ELISA), casein (tested with crush ELISA), and the double‐mark (tested with crush ELISA) by walking over dried residue of the triple mark. This resulted in up to 17% more marked parasitoids in the residue treatment compared with the untreated control. A topical application of the triple mark had no effect on survival of G. ashmeadi compared with the control. The residue treatment resulted in significantly lower mortality than the untreated control, indicating that G. ashmeadi may have fed on the protein in the residue of the triple‐mark, which enhanced longevity.

Assessments of the sylvinite ore dressability at the Starobin potassium salt deposit

Determination of basic quality parameters of sylvinite ores qualities them as economic mineral material only, but does not account for the properties necessary to be considered to classify their dressability. A saturation exploration of the Nezhin mining site involved for the first time a forecast and technological assessment of sylvinite ores in three minable potash horizons, which was made along with estimates of geological fields and was based on a comprehensive study of the mineralogical and technological features of ores in the rock massif and crushed samples.

Rules for confidence intervals of permeability coefficients for water flow in over-broken rock mass

Based on the steady-state seepage method, we used the Mechanical Testing and Simulation 815.02 System and a self-designed seepage instrument for over-broken stone to measure seepage properties of water flows in three types of crushed rock samples. Three methods of confidence interval in describing permeability coefficients are presented: the secure interval, the calculated interval and the systemic interval. The lower bound of the secure interval can be applied to water-inrush and the upper bound can solve the problem of connectivity. For the calculated interval, as the axial pressure increases, the length of confidence interval is shortened and the upper and lower bounds are reduced. For the systemic interval, the length of its confidence interval, as well as the upper and lower bounds, clearly vary under low axial pressure but are fairly similar under high axial pressure. These three methods provide useful information and references for analyzing the permeability coefficient of over-broken rock.

Evaluation of free porosity in shale gas reservoirs (Roseneath and Murteree formations case study)

Organically rich shale rocks represent a voluminous, long-term, global source of natural gas and could be referred to as shale gas. Unlike conventional gas reservoirs, shale gas reservoirs have very low effective porosity and permeability. Therefore, an evaluation of porosity in such a tight rock is a challenge. The Roseneath and Murtree shale formations in the Cooper Basin are believed to be potential shale gas reservoirs in SA. Core samples of Murteree and Roseneath carbonaceous shales from the Della–4 and Moomba–46 wells were collected to measure interstitial and intergranular porosity in these prospective shale gas reservoirs in the Nappamerri Trough. After initial preparation, the shale core samples were investigated to determine the pore size classification and effective free porosity using the mercury injection capillary pressure technique (MCIP). The focused ion beam/scanning electron microscopy (FIB/SEM) technique was then employed to obtain micro and nano scale images of the core samples. Then, helium porosimetry was used on the samples to measure their effective porosity. Finally, the pyknometry method was used on the crushed samples to measure their total intergranular porosity. MICP techniques revealed that the samples were mainly comprised of meso-porosity, with the pore throat diameters between 2–50 nanometres and an effective porosity of less than 2%. Helium porosimetry also showed an average porosity of less than 2%. Liquid pyknometry revealed an average absolute porosity of 30.5% for Murteree shale and 39% for the the Roseneath shale, which is much higher than the results from the MCIP technique and helium porosimetry. This is an indication of having very high isolated porosity and very low permeability. The findings were analysed and validated by the use of SEM images, displaying high amounts of isolated porosity, confirming the high porosity measurement from the pyknometry technique. The results achieved strongly emphasised that gas prone, over-mature, carbonaceous shales have very low effective but very high total porosity. Therefore, it is envisaged that total intergranular porosity holding compressed gas in over-mature source rocks cannot be evaluated using the helium porosimetry and mercury injection techniques. The pyknometry technique supported by the SEM images is an alternative method; however, this method can only measure total, rather than effective, porosity.

Chemical and phase heterogeneity of Ti-Fe-Mn-silica microspherules in crushed ore samples

A Fe-Ti-Mn-silicate microspherule from the heavy mineral fraction of crushed geological samples from an underground mine (Kellyam gold deposit, Yakutia) was examined by transmission electron microscopy. The 400-μm microspherule has a complex chemical composition and contains the following elements (in order of decreasing content): O, Ti, Si, Mn, Fe, Al, Mg, Ca, and K. The material of the micro-spherule shows a polyphase structure and chemical heterogeneity with separation into amorphous oxide-silicate (SiO2) and crystalline metallic (α-Ti + FeTi) constituents. The spherical shape and the character of internal heterogeneity suggest that the microspherule was formed owing to the rapid solidification of a melt droplet. The nanoscale heterogeneity of the microspherule is a consequence of a two-stage process. (1) Liquid immiscibility in the initial melt droplet before its solidification resulted in the incomplete spatial separation of Si + Al and Ti + Fe + Mn and appearance of SiO2 globules with admixtures of Al, Ca, K, Mg, Ti, Fe, and Mn approximately 100 nm in size. (2) Chemical heterogeneity developed subsequently both within the globules and within the matrix at the stage of melt solidification or after the solidification. The second-stage chemical heterogeneity was manifested in (a) the separation of heavy minor element oxides (Ti, Fe, and Mn) from the light elements Si, Al, K, Ca, and Mg(?) within the globules and (b) the separation of the matrix material into crystalline metallic (α-Ti + FeTi) and amorphous oxide-silicate [SiO2-MgO-Mn3O4(?)-Fe2O3(?)-TiO2(?)] parts. The obtained results do not rule out the possibility of formation of such microspherules during drilling operations.

Methods to Estimate the Protection of Soil Organic Carbon within Macroaggregates, 1: Does Soil Water Status Affect the Estimated Amount of Soil Organic Carbon Protected inside Macroaggregates?

The additional mineralized soil organic carbon (SOC) after soil crushing is considered to be the amount of SOC protected within aggregates (>200 μm). This study investigated the effect of soil moisture in crushed and uncrushed soil samples on the calculated amounts of protected SOC in five tropical soils (Arenosol, two Ferralsols, Nitisol, and Vertisol). No differences in soil moisture optimum were observed between crushed and uncrushed soil samples, except in clayey soils with high SOC contents and high SOC mineralization rates (Nitisol and Vertisol). Crushing the soil increased soil respiration by 0.9 to 2.4 times. Soil moisture seemed to be a confounding factor in estimation of the SOC-protected amount only in soil with a high amount of protected SOC or with a low macroaggregate stability (Ferralsol and Vertisol). In these soils, the amount of protected SOC could be influenced by the method used to estimate it.

Experimental study on cooling enhancement of crushed rock layer with perforated ventilation pipe under air-tight top surface

Abstract Under the warm and ice-rich nature of permafrost and the scenarios of climate warming on the Qinghai–Tibet Plateau, it will be necessary to use combinatorial techniques of cooling the ground temperature in the proposed Qinghai–Tibet Express Highway of construction. For the crushed rock highway embankment embedded a perforated ventilation pipe in permafrost regions of the Qinghai–Tibet Plateau, the mechanism of impact on the cooling capability enhanced by a perforated ventilation pipe in the air-tight crushed rock layer was studied using laboratory experiment. All boundary conditions at each edge of the crushed rock sample with dimensions of 100 × 60 × 100 cm except the inlet and outlet of the perforated pipe are air-tight. A ventilation steel pipe with an inner diameter of 8 cm was drilled with many small holes with a diameter of 1 cm and horizontally embedded in the length direction of the crushed rock sample with a depth of 53 cm. The laboratory experiments with a periodically fluctuating air temperature in the inner test tank regulated by program control were performed. The perforated pipe is only ventilated during the negative temperature fluctuation period in the inner test tank. The results show that the heat transfer processes in the crushed rock layer embedded a perforated ventilation pipe with an air-tight surface include pure heat conduction, forced convection that occurs in the crushed rock layer forming directly a pore air circulation in conjunction with the in-duct air by the small holes of perforated pipe wall absorbed from the inner test tank, and convective heat transport between the in-duct air and the inner surface of ventilation pipe wall. When air temperatures in the inner test tank are colder than the pore air temperatures in the crushed rock region around the perforated ventilation pipe, the perforated ventilation pipe can produce a significantly enhanced cooling of the crushed rock layer base due to the direct formation of a complete pore air circulation in the crushed rock layer in conjunction with the in-duct air via the small holes of the perforated pipe wall. When the fluctuating air temperature in the inner test tank rises from a minimum value to a warmer one than the pore air temperature in the crushed rock region around the perforated pipe during the negative temperature ventilating period, a warming process begins to occur in the crushed rock layer due to a warmer in-duct air absorbed from the inner test tank. This stronger warming process in the crushed rock region around the perforated pipe may decrease the cooling capability of the air-tight crushed rock layer. Thus, in order to avoid this warming process at this stage before ventilating end, the ventilating end time of ventilation pipe ought to be brought forward.

Biochemical factors involved in the resistance of some smoked tropical fish samples to insect attack

The role of mineral elements (ppm), protein and oil content (%), and saponification and free fatty acid values in contributing to resistance against insect infestation was investigated in 4 fish species: Clarias gariepinus, Parachuma obscura, Hydrocynus sp., and Malapterus electricus. Smoked fish samples were purchased from a local market in Ilorin, Kwara State, Nigeria, packaged, and maintained at 4 ^°C for 7 days. They were later brought out to acclimatise, and then observed for 4 months for possible natural insect infestation. Next, crushed samples of each species were analysed using conventional chemical analysis in order to assess the role of some elements and biochemical compounds in inducing resistance. The results showed that insect infestation did not occur after the period of storage (4 months) and chemical analysis showed that 3 samples lacked lead (Pb), a heavy metal not required in trace amounts, but contained other heavy metals required in trace amounts, such as Fe, Mn, Co, and Cu. Protein content in the 4 samples was average (50%), but oil content was low. Hydrocynus sp. and Malapterus electricus had an acid value below 50 mg KOH/g. Additionally, all the samples had high a saponification value (above 500 mL/g). The presence of iron (>=1.5), high protein (%) and saponification values, low oil content, and low acid values of between 35 and 90 were the elements and biochemical constituents that prolonged the shelf life of the fish species studied.

Bacterial assemblages differ between compartments within the coral holobiont

It is widely accepted that corals are associated with a diverse and host species-specific microbiota, but how they are organized within their hosts remains poorly understood. Previous sampling techniques (blasted coral tissues, coral swabs and milked mucus) may preferentially sample from different compartments such as mucus, tissue and skeleton, or amalgamate them, making comparisons and generalizations between studies difficult. This study characterized bacterial communities of corals with minimal mechanical disruption and contamination from water, air and sediments from three compartments: surface mucus layer (SML), coral tissue and coral skeleton. A novel apparatus (the ‘snot sucker’) was used to separate the SML from tissues and skeleton, and these three compartments were compared to swab samples and milked mucus along with adjacent environmental samples (water column and sediments). Bacterial 16S rRNA gene diversity was significantly different between the various coral compartments and environmental samples (PERMANOVA, F = 6.9, df = 8, P = 0.001), the only exceptions being the complete crushed coral samples and the coral skeleton, which were similar, because the skeleton represents a proportionally large volume and supports a relatively rich microflora. Milked mucus differed significantly from the SML collected with the ‘snot sucker’ and was contaminated with zooxanthellae, suggesting that it may originate at least partially from the gastrovascular cavity rather than the tissue surface. A common method of sampling the SML, surface swabs, produced a bacterial community profile distinct from the SML sampled using our novel apparatus and also showed contamination from coral tissues. Our results indicate that microbial communities are spatially structured within the coral holobiont, and methods used to describe these need to be standardized to allow comparisons between studies.

Determination of Sperm Concentration for Small-Bodied Biomedical Model Fishes by Use of Microspectrophotometry

The goal of this study was to establish an efficient method for determination of sperm concentration requiring only 1-2 microL of sample by use of microspectrophotometry. The objectives were (1) determination of wavelengths with absorbance profiles appropriate for analysis of sperm suspensions from zebrafish Danio rerio, green swordtail Xiphophorus helleri, and medaka Oryzias latipes collected by crushing of dissected testis or by stripping of live males; (2) generation of standard curves and equations between sperm sample absorbance and sperm concentration estimated by hemocytometer counts; (3) accuracy verification of equations for estimating concentration by microspectrophotometry; and (4) analysis of the precision in generating equations and estimation of sperm concentration. Within the visible wavelengths (380-750 nm) there was no single maximal absorbance peak. For zebrafish, a linear correlation was established with an effective absorbance range of 0.034-0.936 for crushed samples, and 0.028-0.961 for stripped samples at 400 nm. For Xiphophorus, the effective absorbance range was 0.014-1.154 for crushed samples, and the effective range was 0.038-1.082 for stripped samples. For medaka, the effective range was 0.041-0.896 for crushed samples. The accuracy of these equations was verified by comparison of sample concentrations counted with hemocytometer and calculated with equations, and no significant differences (p = 0.447) were observed. Measurement of serially diluted aliquots from pooled samples verified the precision of techniques used. Overall, this confirmed that microspectrophotometric estimation of sperm concentration is accurate, efficient, and sample-saving for use with small-bodied fishes.

Decay Dynamics of Excited Nd$^{+3}$ Ions in Nd:YVO$_{4}$ Following Weak Excitation

Decay dynamics of the upper-laser energy level of Nd:YVO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> are re-evaluated. In order to reduce the effects of re-absorption, comparative measurements among crushed samples with different doping concentrations were conducted. The magnitude of re-absorption was estimated experimentally by comparing the relative intensity of the emitted fluorescence spectra at different wavelengths, and estimated theoretically by employing a simplified model. The temporal decay dynamics are found to be non-exponential and the associated rate parameters are presented. The room temperature intrinsic life time value of the <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3/2</sub> energy level is found to be significantly shorter than the value accepted today.

Analysis of colloids released from bentonite and crushed rock

Inorganic colloids are present in natural groundwater but colloids can also be produced from degraded Engineered Barrier System (EBS) materials. The potential relevance of colloids for radionuclide transport is highly dependent on the release and stability of colloids in different chemical environments and their interaction with radionuclides. In this work, release and stability of inorganic colloids were determined from bentonite and crushed rock which will be used in the tunnel back-fill. In the batch dispersion experiments, MX-80 bentonite powder or crushed rock samples of mica gneiss, unaltered and two altered tonalites were added to Milli-Q water, saline OLSO, and low salinity Allard reference water with adjusted pH values 7–9. After 4 months, pH, particle size distribution, zeta potential, morphology, elemental composition, and colloid concentration were analyzed. The release and stability of colloids depended significantly on groundwater salinity, pH, and the degree of alteration of the rock. In saline OLSO, zeta potential values near zero, wide particle size range, and low colloid concentrations indicated particle aggregation and instable colloidal dispersion. In low salinity Allard and Milli-Q water, high or moderate negative zeta potential values, smaller particle sizes, and higher colloid concentrations than in OLSO indicated the existence of stable colloids.

The age of unusual xenogenic zircons from Yakutian kimberlites

Several spindle-shaped grains of zircon, which have a small size (<0.25 mm) and a distinct purplish pink coloration were found in the crushed samples of kimberlites from the Aykhal, Komsomolskaya-Magnitnaya, Botuobinskaya (Siberian platform), and Nyurbinskaya (Yakutia) pipes and olivine lamproites of the Khani massif (West Aldan). U-Pb SHRIMP II zircon dating performed at the VSEGEI Center for Isotopic Research yielded the ages of 1870–1890 Ma for the pipes of the Western province (Aykhal and Komsomolskaya) and 2200–2750 Ma for the pipes of the eastern province (Nyurbinskaya and Botuobinskaya), which allowed us to consider these zircons to be xenogenic to kimberlites. Although these zircons resemble in their age and color those from the granulite xenoliths in the Udachnaya pipe [2], no other granulite minerals are found there. Thus, major geological events in the mantle and lower crust, which led to the formation of zircon-bearing rocks, happened at 1800–1900 Ma in the northern part of the kimberlite province, whereas in the Eastern part of the province (Nakyn field) these events were much older (2220–2700 Ma). It is known that the period of 1800–1900 Ma in the Earth’s history was accompanied by intense tectonic movements and widespread alkaline-carbonatite magmatism. This magmatism was related to plume activity responsible for overheating the large portions of the mantle to the temperatures at which some diamonds in mantle rocks would burn (northern part of the kimberlite province). In the Nakyn area, the mantle underwent few or no geological processes at that time, and perhaps for this reason this area hosts more diamondiferous kimberlites. The age of olivine lamproites from the Khani massif is 2672–2732 Ma. Thus, these are some of the world’s oldest known K-alkaline rocks.