Bulk Grain Research Articles

Challenges of sampling grain for mycotoxin analysis

During growth and post-harvest storage, fungi can infect grain and produce secondary metabolites known as “mycotoxins ”. Some mycotoxins are regulated due to their potential hazardous health effects. Thusly, analysis of bulk grain consignments for mycotoxins is common in the grain trade. The heterogeneity of bulk grain with respect to deoxynivalenol (DON) and ochratoxin A (OTA), two regulated mycotoxins, was investigated. Variation of concentrations amongst individual wheat kernels was assessed, along with the variation within sub-samples and test portions produced from 10 kg laboratory samples, and amongst 500 t increments sampled during loading of bulk shipments (4,600 to 55,000 t). Concentrations in individual kernels ranged from < 0.02 to 583 mg/kg for OTA and < 0.3 to 414 mg/kg for DON. Analysis of the distribution of concentrations was limited due to the difference between the sample sets available for use; one was naturally infected (DON) and the other was inoculated and incubated under laboratory conditions (OTA). Bulk shipments were sampled during loading using a Canadian Grain Commission-approved automated cross-stream diverter-type sampler and in-line divider. Increments were combined, and 10 kg laboratory samples were prepared from the resulting composite using a Boerner divider, comminuted using a rotor beater mill, and sub-sampled using rotary sample division to produce representative sub-samples and test portions. Concentrations of OTA in the 500 t increment samples varied from < 0.25 to 22.9 µg/kg; DON varied from < 0.05 to 0.67 mg/kg. Within shipments, the OTA concentrations varied more amongst increments than did DON. The coefficients of variation for OTA ranged from 42 to 95% which were 2-4× greater than for DON. The results illustrate heterogeneity of bulk wheat relevant to international trade and regulated mycotoxins. Differences observed for DON and OTA also reflect how biological differences in mycotoxin production contributes to the challenges faced in analysing bulk whole grain for mycotoxins.

Ergot in Canadian cereals – relevance, occurrence, and current status

Ergot is a fungal disease that occurs on cereals and grasses, including rye, oat, wheat, and barley. The ergot pathogen, Claviceps purpurea, infects the floret, and as infection progresses, it replaces individual kernels, appearing on the head as darkly coloured fungal bodies called sclerotia. Ergot is a grain-grading factor in Canada and can affect grain quality and value, as well as safety due to production of ergot alkaloids. Testing of durum fortified with ergot sclerotia showed that the presence of sclerotia resulted in black specks in semolina and pasta, but had no impact on milling performance or end-product quality. Surveillance performed as part of the Canadian Grain Commission’s annual Harvest Sample and Cargo Monitoring Programs provided insights into ergot incidence and severity in different grains, growing locations, and years, as well as the presence of ergot alkaloids. Analysis of more than 230 000 Harvest Sample Program grain samples from western Canada across 25 years showed the highest ergot incidence and severity occurred in rye, followed by bread and durum wheat, and then barley and oats. Ergot incidence and severity varied annually, but only incidence increased over time. Analyses of bulk grain shipments indicated that the presence of ergot alkaloids reflected the disease incidence observed in the harvest samples (median ergot alkaloid concentrations in wheat and durum > oats and barley). Data on ergot alkaloids from the Cargo Monitoring Program also showed that the Canadian bulk grain-handling system mitigated the variability in annual ergot incidence and severity observed in harvest samples.

Review on Grain Refinement of Metallic Materials to Regulate Cellular Behavior

Metallic materials have been widely used as orthopedic implants in clinics for their good mechanical, physical, and chemical properties, but their slow osseointegration rate is still one of the main issues causing implantation failure. Grain refinement has recently attracted wide attention for its effective improvement of cell–material interaction for biometals. In this review, the surface and bulk grain refinement mode and the influence of grain size reduction of various metallic materials including titanium, stainless steel, magnesium, zirconium, tantalum, and their alloys as well as NiTi shape memory alloys on the cell responses is summarized in detail. It is hoped that this review could help biomaterials-related researchers to understand the grain refinement of metallic materials in a timely manner, thus boosting the development of biomedical metals for clinical use.

Hyperspectral imaging for classification of bulk grain samples with deep convolutional neural networks

Near Infrared hyperspectral imaging (HSI) offers a fast and non-destructive method for seed quality assessment through combining spectroscopy and imaging. Recently, convolutional neural networks (CNN) have shown to be promising tools for red-green-blue (RGB) image or spectral cereal classification. This paper describes the design and implementation of deep CNN models capable of utilizing both the spatial and spectral dimension of HSI data simultaneously for analysis of bulk grain samples with densely packed kernels. Classification of eight grain samples, including six different wheat varieties, were used as a test case. The study shows that the CNN architecture ResNet, originally designed for RGB images, can be adapted to use the full spatio-spectral dimension of the HSI data through adding a linear down sample layer prior to the conventional ResNet architecture. Using traditional spectral pre-processing methods before passing the data to the CNN does not improve the classification accuracy of the networks, while a channel-wise image standardization improves the accuracy significantly. The modified ResNet applied to the full spatio-spectral dimension has a classification accuracy of up to 99.75 ± 0.02%, outperforming both purely spectral (86.5 ± 0.1%) and purely spatial (98.70 ± 0.01%) based methods in terms of accuracy, indicating that utilizing spatio-spectral correlation can improve sample classification, but also that grain classification is primarily solved using spatial information. The findings reported in this paper demonstrate how CNN networks can be designed to leverage spatio-spectral information in hyperspectral data. The combination of HSI and spatio-spectral CNN networks shows a possible method for fast prediction of bulk grain quality parameters where both spectral and spatial properties of the grains are important.

Exploration and tuning of Al2O3/Mo composite for enhancement of anti-corrosion and tribological characteristics in zinc phosphate conversion coatings

Recently, phosphate conversion coatings have been modified by transition/non-transition metal oxide with distinguished characteristic features such as corrosion resistance, wear resistance, lubrication and adhesion. The present paper explores the development of Al2O3/Mo composite incorporated zinc phosphate coatings on galvanized steel for achieving higher corrosion-resistant characteristics with an added advantage of tribological performance. Incorporation of Mo leads to the phase transformation from γ to α-Al2O3, which ensures the subsequent crystallization of alumina particles by the anisotropic grain growth of Mo content. Particle size, elemental composition and morphology of the Al2O3/Mo composite are tuned for retaining the stable crystalline alpha phase of the composite. The optimum concentration of the tuned content of Al2O3/Mo composite in the phosphating solution can effectively perform as an active nucleating source for the establishment of more compact, homogeneous and dense zinc phosphate crystal growth and coverage in the galvanized steel surface by significantly reducing the activation energy during the phosphating process. The resultant composite phosphate coating ensures the formation of a large quantity of crystalline hopeite rich phase compared to other coatings, which effectively acts as an insulator during the electrochemical reaction by imparting a corrosion-resistant barrier between the substrate and corrosive media. Uniform distribution of composite particles at the grain boundaries and at the bulk grain composition is also achieved. Lower average surface roughness (Sa), root mean square surface roughness (Sq), maximum height (St), surface skewness (Ssk) and higher surface kurtosis (Sku) values are acquired for better anti-corrosion properties with excellent tribological performance. The higher Rp and Rct values with lower Cdl and corrosion rate values of the tuned composition of Al2O3/Mo composite based zinc phosphate coating confirms the better porosity and thereby enhances the corrosion-resistant performance due to the sealing action of the composite.

High-Voltage Induced Surface and Intragranular Structural Evolution of Ni-Rich Layered Cathode.

Layered Ni-rich lithium transition metal oxides are promising cathode materials for high-energy-density lithium-ion batteries. These cathodes, however, suffer from rapid performance decay under high-voltage operation. In this work, the electrochemical properties and structural evolution of the LiNi0.8 Mn0.1 Co0.1 O2 (NMC811) cathode upon high-voltage cycling are investigated. The results show that the NMC811 cathode not only experiences surface evolution with the formation of Li-deficient rock-salt layers, but also suffers from drastic intragranular structural changes inside bulk grains after high-voltage cycling. Direct evidence for the formation of transition-metal/Li disordering domains with uneven Li content and lattice plane distortion at the internal grains of 4.6V-cycled NMC811 are provided with their atomic ordering and spatial distribution clearly resolved. The complex intragranular structural changes impede Li+ diffusion inside bulk material, resulting in kinetic limitation and capacity loss. The results demonstrate that the high-voltage cycling would induce severe structural degradation at the grain interior of the cathode material beyond surface evolution, which contributes significantly to the rapid performance decay of the NMC811 cathode. The findings provide new insights for developing effective countermeasures to mitigate this degradation pathway.

Recrystallization sintering and characterization of composite powders composed of two types of SiC with dissimilar particle sizes

AbstractPure silicon carbide (SiC) ceramics were prepared through recrystallization sintering by using two types of SiC powder, with different particle sizes, as the raw materials. The effects of the fine powder content on the bulk density, porosity, flexural strength, and grain morphology were investigated. In the synthesis process, silicon nitride (Si3N4) was used as the sintering additive that decomposed and transformed into SiC to promote the growth of SiC grains. The added fine powder was exploited in the evaporation and condensation process and grain amalgamation caused by the movement of the grain boundaries. Thus, a dissimilar fine powder content modulated the microstructure and mechanical strength of the SiC ceramics. The results indicate that the bulk density and flexural strength increase to a maximum of 2.12 g/cm3, 44.2 MPa, respectively, when the fine powder content is 40 wt.%. Three kinds of grain morphologies, that is, uniform equiaxed grains, round, equiaxed grains, and hexagonal platelet grains, and the maximum average pore size (3.62 μm) are obtained when the fine powder content is between 0 wt.% and 60 wt.%. In addition, the main crystal phase 6H‐SiC is partially converted to 4H‐SiC when the fine powder content is up to 60 wt.%.

Enabling Traceability in Agri-Food Supply Chains Using an Ontological Approach

Abstract Traceability of food products to their sources is critical for quick responses to food emergencies. US law now requires stakeholders in the agri-food supply chain to support traceability by tracking food materials they acquire and sell. However, having the complete and consistent information needed to quickly investigate sources and identify affected material has proven difficult. There are multiple reasons that food traceability is a challenging task, including diversity of stakeholders and their lexicons, standards, tools, and methods; unwillingness to expose information about internal operations; lack of a common understanding of the steps in a supply chain; and incompleteness of data. The objective of this work is to address the traceability challenge by developing a formal ontology that can provide a shared and common understanding of the traceability model across all stakeholders in bulk food supply chains. A formal ontology can support semantic mediation, data integration, and data exploration, thus improving the intelligence and reliability of trace and track process. The Industrial Ontologies Foundry (IOF) procedures and principles are employed in the development of the supply chain traceability ontology. Basic Formal Ontology (BFO) is selected as the top-level ontology. A bottom-up approach is also adopted in a sense that a real use case related to the bulk grain domain is selected to be used for requirements definition and ontology validation. A software tool for visualization of the traceability graph is developed to validate the developed ontology based on simulated data. The test and validation results indicate that the developed ontology has the expressivity needed to represent the semantics of traceability data models within the scope of the selected use case. Also, it was observed that the developed supply chain traceability tool can effectively facilitate the track and trace process through visualizing the Resource Description Framework (RDF) triples, thus eliminating the need to formulate complex SPARQL queries for information retrievals.

Developing a statistical model for the active ventilation of a grain layer with high moisture content

The most important stage in the technological operations for grain production is its post-harvest processing. At this stage, the quality of the grain masses is lost because the temperature condition inside bulk grain is almost never checked during temporary storage. In order to increase the technological efficiency of primary grain processing and storage, an installation has been designed that could preserve the quality of grain at low-capacity enterprises or during temporary storage. As the self-heating of grain during storage is a serious issue, the installation would also help solve the problem related to the temporary lack of storage facilities. Thus, using active grain ventilation makes it possible to improve the resistance of grain masses to storage. The available body of research into energy-saving drying processes, active ventilation, and purification of grain from light impurities mainly resolve highly specialized technological tasks. Of interest are those studies that aim to design and implement the rational equipment structure for the active ventilation and cleaning of grain from light impurities, which make it possible to practically execute non-stationary modes. This paper considers the efficiency of active ventilation and the reduction of energy costs depending on the installation's structural parameters; specifically, the height of the chamber and the speed of supply of warm air are selected. The height of the working chamber of 1 m and the air velocity of 1.1–1.4 m/s have been experimentally proven and theoretically substantiated.

Laser-clad Nb(Ta)TiZr medium-entropy alloy coatings on pure Zr sheet: Microstructural characteristics, hardness and wear resistance

In this work, two Nb(Ta)TiZr medium-entropy alloy (MEA) coatings were fabricated successfully on a commercially pure Zr sheet by pulsed laser cladding. Their phase constitutions, microstructural characteristics, chemical compositions and grain orientations were well characterized and analyzed by using X-ray diffraction (XRD), electron channeling contrast (ECC) imaging, energy dispersive spectrometry (EDS) and electron backscatter diffraction (EBSD) techniques, with hardness and wear resistance measured and correlated with the microstructural characteristics as well. Results show that irregular-shaped bulk grains (BCC solid-solution phase) are formed in the two Nb(Ta)TiZr MEA coatings (cladding zones), both of which have a thickness of ∼800 μm with good metallurgical bonding to the substrate. After adding Ta, grains in the MEA coating are slightly refined. The phase constitutions in both the coatings agree with calculations based on several theoretical parameters. Hardness tests show that the NbTiZr and the NbTaTiZr coatings have hardnesses of 360 ± 18 HV and 430 ± 28 HV, respectively, ∼1.8 times and ∼2.2 times that of the substrate (196 ± 4 HV). This can be ascribed to combined effects of grain refinement strengthening, solid solution strengthening with denser low angle boundaries in the MEA coatings. Specific wear rates of the NbTiZr and the NbTaTiZr coatings are only ∼17% and ∼6% of that of the substrate, respectively, indicating markedly improved wear resistance. This is demonstrated to be closely related to complete oxide films easily formed on the coatings with oxidation and abrasive wear mechanisms.

3D Pore Structure Characterization of Stored Grain Bed

Highlights An image analysis for reconstruction of 3D pore structure within bulk grain was presented. Mathematical models for porosity and tortuosity were developed from the 3D reconstructed images. The mathematical models can be incorporated in computational model of flow through bulk grains. Abstract. An image analysis technique for reconstruction of the complex 3D pore structure within bulk grain from 2D section images was presented. The technique relies on aligning successive 2D images of cut-sections obtained from colored-wax solidified soybean grain beds, which were then subjected to image processing using ImageJ software developed by the National Institute of Health (NIH, Bethesda, Md.) for the reconstruction and visualization of different airflow paths within the bulk grain. Porosity and tortuosity values were quantified from the 3D image volume and 3D reconstructed inter-connected airflow paths to develop empirical mathematical models for predicting porosity and tortuosity as a function of compaction due to the pressure exerted by the grain depth. Results indicated that the rate of decrease in porosity was higher at the lower compaction grain depth and then gradually approached a minimum value as the compaction grain depth increased. At the top of the compacted grain, the porosity of the tested soybean bed was determined to be 0.42 and reduced to 0.34 at a compaction pressure of 14.2 kPa (equivalent to a compaction grain depth of 25 m). Tortuosity increased with the compaction pressure from 1.15 to 1.58 at a compaction pressure of 14.2 kPa (equivalent to 25 m of grain depth), or by 37.4%. Keywords: Grain bed, Image analysis, Pore structure, Porosity, Tortuosity.

Portable-Mechanical-Sampler System for Real-Time Monitoring and Predicting Soybean Quality in the Bulk Transport

During transport, the grains can deteriorate and lose quality due to the increase in their metabolic activity. Thus, it is suggested that the monitoring of the intergranular variables and the prediction of the grain mass quality can collaborate for the decision making about the time of transport and unloading. Therefore, an equipment comprising a mechanical-portable sampler with a hardware device and DHT22 and MHZ-14 sensors was proposed in this study for the real-time monitoring of the temperature, relative humidity, and CO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> of the intergranular air, with advantages about others technologies, since it possibility to predict the physical quality of soybean mass during bulk transport. In addition, the equipment allows sampling the grain mass in the profile to analyze its quality on the laboratory to prove the results obtained in the monitoring and prediction. The equipment was developed using low-cost materials, sensors, and components and tested in the laboratory and at a full scale. The system was validated by comparing the results of the indirect measurement with those of the grain quality analyses. Thus, the equipment can be applied for the monitoring of bulk grain transport to avoid quantitative and qualitative losses and to collaborate in the field of food safety and post-harvest logistics.

Characterization and Visualization of Grain Boundary Disconnections

We introduce a method to visualize dislocations along grain boundaries at the atomic level. It uses an atomic-level Nye tensor, representing the dislocation density. To calculate the Nye tensor at grain boundaries, we extend the Hartley-Mishin strain gradient calculation to the displacement shift complete lattice. We show that the method is effective in visualizing disconnections and the dislocation content of grain boundary phase junctions in body-centered cubic tungsten, as well as face-centered cubic copper. In addition, we use the method to characterize the morphology of a two-dimensional grain boundary phase nucleus in a symmetric tilt grain boundary in tungsten. This method can be applied to both bulk dislocations and grain boundary disconnections, which makes it ideal for studying the interactions and reactions of bulk dislocations with grain boundaries, and grain boundary disconnections.

Prediction of milling yield in wheat with the use of spectral, colour, shape, and morphological features

Image and spectral data captured from 996 wheat samples were used to construct predictive models of flour milling yield (MY)%. The data consisted of multispectral images of individual wheat grains, as well as near-infrared reflectance spectra of corresponding bulk grain. Samples were characterized by sets of features extracted from the data, broadly grouped into spectral features, and image features (mean and standard deviations of sample grain features), including the colour, shape, and morphology of the grains. Image feature extraction included the use of deep learning for classification of grain orientation, estimation of the relative size of the embryo and endosperm, and a method for estimation of grain crease-depth. Extracted features were used as independent variables for the selection of regression models of MY%. The models included multiple linear regression, support vector regression, and Gaussian process regression (GPR). Along with MY%, physical grain traits related to MY%, including test weight (TW), and grain weight (GWT), were modelled to compare the performance of the feature and regression model combinations across traits. The combination of all features as input variables for a GPR model was found to give the best accuracy, with adjusted-R 2 cross-validation values of 0.81, 0.94, and 0.61, for TW, GWT, and MY, respectively. The corresponding cross-validation RMSE of the MY% model was 1.24%. • MY prediction accuracy was improved by combining spectral and image features. • Image features included grain shape, colour, and morphology. • Embryo size and crease depth were extracted from individual grain images. • GPR models were found to outperform SVR and MLR for modelling MY.

Pb0.8Ln0.2Fe0.1Cr0.1Ti0.8O3 (Ln = La, Nd and Sm): exploring the structure-property characteristics

The structure-property response of Pb0.8Ln0.2Fe0.1Cr0.1Ti0.8O3 (Ln = La, Nd and Sm) synthesised by solid-state reaction technique was analysed as a function of frequency and temperature using impedance spectroscopy. We observe a series of semi-circular arcs denoting electrical processes owing to bulk material, grain boundaries and interfacial polarisation in the output complex plane plots. The relaxation spectrum is affected by the increase in direct current (dc) conductivity at high temperature range. The activation energies deduced from dc conductivity plots are 0.811 eV, 0.829 eV and 0.875 eV respectively. We have observed the significant substitution effect on the electrical properties.

Carbonate strength classification based on depositional textures and fossil content of the Lower Eocene Drunka Formation, Assiut Area, central Egypt

The present study reports petrographic and physico-mechanical analyses conducted on the lower Drunka Formation in the Assiut Area of Central Egypt. The study investigated the percentage of carbonate content and percentage of allochems “Ach” and their impact on the petrophysical features using correlation and multivariate regression analyses. This study analyzes the petrophysical characterization of Drunka Formation rocks and the effect of fossil content on them. The carbonate rock samples derived from the lower Drunka Formation were studied to evaluate the compressive strength , dry and saturated unit weight, porosity, and acoustic wave velocities. The petrographic examination of the rock samples was conducted to understand the facies characteristics, size and percentage of grains, matrix type and extent of diagenesis . Various microfacies associations were also detected within the examined samples, such as lime-mudstone, echinoidal bioclastic wackestones, nummulitic/miliolid wackestones, bioclastic peiodal packstone, echinoidal packstone and nummulitic grainstone . Petrophysical analyses displayed a wide range of porosity and dry bulk density values from 1.3 to 2.75% and 2.31–2.48 g/cm 3 , respectively. The wet bulk density and grain densities are between 2.33˗2.50 and 2.35˗ 2.57 g/cm 3 , respectively. The dry ultrasonic wave velocity “V p” was observed between 2926 and 5549 m/s, whereas the saturated ultrasonic wave velocity “V p “was estimated between 3067 and 5875 m/s. The Unconfined Compressive Strength (UCS) of the tested samples was 22 ≤ UCS ≤ 82 MPa while the slake durability index was recorded as 94.37 ≤ SDI ≤ 98.7%. The Brazilian test indices characterized the studied rock samples as highly porous rocks and showed the values of 1.47 ≤ Brazilian ≤ 5.13 MPa. Finally, for all tested facies, the Böhme test data have a minimum, maximum, and an average of 12.98, 25.95, and 19.04 cm 3 /50 cm 2, respectively. The study's findings showed that, except for the mineral grain scale, the physico-mechanical properties are highly dependent on the petrographic characteristics. The study also revealed that the Ach% and the rock's carbonate content significantly affect the rock's petrophysical and mechanical properties under investigation. The mechanical properties such as UCS, tensile and point load test. increase with increasing carbonate content and decreasing with increasing Ach% of the rock. This paper presents an extensive dataset of physical parameters of a carbonate formation in Egypt; many empirical relationships are presented for predicting mechanical properties. This provides site-specific predictive value; the relationships can be used for all carbonate rocks worldwide with broader international significance. • Classification of strength from texture is proposed based on fossil and carbonate content. • This study analyzes the petrophysical characterization of Drunka Formation rocks and the effect of fossil content on them. • This paper introduces a new strength classification of carbonate rocks based on allochems and carbonate content. • The depositional texture of carbonate rocks has a significant impact on variations of physico-mechanical properties of rocks. • Diagenesis has a remarkable effect on rock strength.

Mobilization and fractionation of Ti-Nb-Ta during exhumation of deeply subducted continental crust

The behavior of Ti-Nb-Ta is crucial to reveal the genesis of island arc magmatism. However, mobilization and fractionation of Ti-Nb-Ta in subduction zone settings remain poorly understood. The discovery of felsic veins rich in coarse-grained rutile within retrograde eclogite of the North Qaidam UHP metamorphic belt provides a unique and novel opportunity to study age variation during rutile formation and alteration, as well as Ti-Nb-Ta mobility and fractionation during fluid/melt-rock interaction. Rutile high-resolution elemental mapping, and U-Pb bulk grain (ID-TIMS), and in-situ U-Pb geochronology have been utilized to focus on the properties of rutile in both, felsic vein and retrograde eclogite host to gain insight into possible similarities and differences. Three groups of rutile were distinguished according to its host rock, trace elements signature, and genetical connection to ilmenite: eclogite-hosted rutile (Rt-1), felsic vein-hosted rutile not associated with ilmenite (Rt-2a), and associated with ilmenite (Rt-2b). Field evidence and rutile trace elements characteristics document the source of vein-hosted rutile to be mainly derived from the eclogite during fluid/melt-rock interaction. Principal Component Analysis reveals that Nb, Ta, Sn, and W are more enriched in Rt-2a compared to Rt-1; Rt-2b has higher Nb, U, and Hf than Rt-2a. High-resolution mapping across large rutile grains shows the enrichment of high field strength elements (HFSEs) in rutile near to ilmenite, which indicates a HFSEs back diffusion from the rutile–ilmenite boundary during the replacement of rutile by ilmenite. The Nb/Ta ratios of Rt-2a are lower than those of Rt-1, which result from different partition coefficients of Nb and Ta during fluid/melt-rock interaction. The diffusion-influenced rutile exhibits suprachondritic Nb/Ta ratios and demonstrates that diffusion of Nb in rutile is higher than that of Ta under identical P-T conditions. Rutiles Rt-1 and Rt-2a yield consistent 206Pb/238U ages of 426–423 Ma, which is similar to the 433 ± 3 Ma determined by ID-TIMS results of bulk rutile grains. This indicates that Ti-Nb-Ta must have been mobilized during the exhumation of deeply subducted continental crust. However, the diffusion-influenced rutile shows a large variation of ages compared to the rutile not associated with ilmenite, demonstrating that the back-diffusion may affect the U-Pb system in rutile. Therefore, when rutile is partially altered into ilmenite or titanite, its dating should be used with caution. Thus, this study demonstrates volume diffusion is a very important geological process to result in extreme HFSEs fractionation and age variation of rutile on the mineral scale. The rutile aggerates that occur in the felsic veins in 3–5 m distance to the adjacent retrograde eclogite suggest that Ti-Nb-Ta-rich melts/fluids were transported over a distance of at least several meters and that rutile does not represent a residual phase of the Na-Si-Al-, F- and CH4-bearing fluid/melt environment that formed during anatexis of the subducted continental crust. The formation of rutile-rich aggregates during the generation, transport, and crystallization of subducted continental crust-derived melts/fluids in the deep roots of orogenic belts may be a critical trigger for the depletion of HFSEs in arc magmatic rocks during the formation of the continental crust.

Adaptation of Crushed Rock Analysis to Intact Rock Analysis To Improve Assessment of Water Saturation and Fast Pressure Decay Permeability

Summary Legacy crushed rock analysis, as applied to unconventional formations, has shown great success in evaluating total porosity and water saturation over the previous three decades. The procedure of crushing rock into small particles improves the efficiency of fluid recovery and grain volume measurements in a laboratory environment. However, a caveat to crushed rock analysis is that water and volatile hydrocarbons evaporate from the rock during the preparatory crushing process, causing significant uncertainty in water saturation assessment. A modified crushed rock analysis incorporates nuclear magnetic resonance (NMR) measurements before and after the crushing process to quantify the volume of fluid loss. The advancements improve the overall total saturation quantification. However, challenges remain in the quantification of partitioned water and hydrocarbon loss currently derived from the NMR spectrum along with its uncertainty. Furthermore, pressure decay permeability from crushed rock analysis has been reported to have two to three orders of magnitude difference between different laboratories. The calculated pressure decay permeability of the same rock could even vary by several orders of magnitude with different crushed sizes, which questions the quality of the crushed pressure decay permeability. In this paper, we introduce an intact rock analysis workflow on unconventional cores for improved assessment of water saturation and enhanced quantification of fast pressure decay matrix permeability from intact rock. The workflow starts with acquisition of NMR T2 and bulk density measurements on the as-received state intact rock. Instead of crushing the rock, the intact rock is directly transferred to a retort chamber and heated to 300°C for thermal extraction. The volumes of thermally recovered fluids are quantified through an image-based process. The grain volume measurement and a second NMR T2 measurement are performed on post-retort intact rock. The pressure decay curve during the grain volume measurement is then used for calculating the pressure decay matrix permeability. Total porosity is calculated using the bulk volume and grain volume of the rock. Water saturation is quantified using the total volume of recovered water. In addition, the twin as-received-state rocks are processed through the crushed rock analysis workflow for an apple-to-apple comparison. Meanwhile, the pressure decay permeability of the post-retort intact sample is cross-validated against the steady-state gas permeability of the same post-retort sample. The introduced workflow has been tested successfully on different formations, including Bakken, Bone Spring, Eagle Ford, Cotton Valley, and Niobrara. The results show that total porosities calculated from intact rock analysis are consistent with total porosities from crushed rock analysis, while water saturations from the new workflow are an average 8% saturation unit (SU) [0.2 to 0.7% porosity unit (PU) of bulk volume water (BVW)] higher than those from the prior crushed rock workflows. The study also indicates that for some formations (e.g., Bone Spring), the fluid loss during the crushing process is dominated by water; however, for some other formations (e.g., Bakken), the hydrocarbon loss is significant. Pressure decay permeability quantified using intact rock analysis is also confirmed within an order of magnitude of steady-state matrix permeability.

Bias dependent admittance spectroscopy of thin film solar cells: KF post deposition treatment, accelerated lifetime testing, and their effect on the CVf loss maps

Modern solar cell designs include an always larger variety of elements and additional layers. This approach is usually successful and leads to the development of increasingly efficient materials. However, scientifically, it makes the drawing of accurate conclusions always more challenging, due to the growing number of elements, possible defects, interfaces, and barriers. To try and remedy this problem, we developed a novel way to investigate solar cells by representing bias dependent admittance spectroscopy (CVf) measurement data in the form of a 2D loss map. In this contribution, we elaborate how this technique can be used experimentally, present some concrete results we obtained from measurements on ultra-thin CIGS solar cells and explain how they can be interpreted. We identify 3 major response domains on our typical CVf loss maps. One at high frequency that covers most of the bias range and can be related to series resistance. One at low frequency, mostly visible at strong positive and negative biases, which is related to shunt and dissipation. The last response domain, close to 100 kHz and impacting most of the bias range, can be identified as a defect response of the material. Using CVf measurements on samples with KF post deposition treatment, known for its grain boundary passivation properties, and samples that were previously submitted to accelerated lifetime testing in damp heat conditions, the impact of bulk defects, grain boundaries and conduction band offsets are investigated.

Prospects for Use of Biological Control of Insect and Mites for the Food Industry in North America

There are a number of strategies used to mitigate and control insect infestations in stored products and stored product facilities in North America and globally. Fumigation remains one of the main techniques used, particularly in bulk grain. Other techniques are also utilized effectively, such as the use of extreme temperatures and the use of biological control agents, but are mainly restricted to organic products and to Europe, respectively. Here, we review the past research conducted in the field of biological control for pests of stored products in North America and in Europe, its past and present successes in Europe, its challenges, and what we can learn from them to develop biological control as a viable option to problems of insect pests of stored products in North America.