Primary Grains Research Articles

The Influence of Undercooling ΔT on the Structure and Tensile Strength of Grey Cast Iron.

Inoculation of cast iron has become a commonly used metallurgical process, which is carried out in a foundry in order to improve the mechanical properties of utility alloys. It consists in changing the physicochemical state of the melted alloy. This change is caused by the introduction of cast iron with a low ability to nucleate graphite, shortly before pouring a small mass of the substance—an inoculant that increases the number of active nuclei. It is also justified that the literature often connects an increase in the tensile strength UTS of the inoculated grey cast iron, with changes in the characteristics of the particles of graphite. However, in strongly hypoeutectic cast iron, in which a large number of primary austenite grains crystallize, the interdendritic distribution of graphite is usually the result. It also follows that the nature of the graphite precipitates is determined by the mutual relations between the interfacial distances in eutectic grains and the interdendritic distances in the grains of primary austenite occurring in the Fe–C alloys. The article presents the influence of the inoculant on the characteristics of the precipitation of primary austenite grains in relation to the sulphur content in grey cast iron with flake graphite. The study also showed that primary grains in grey cast iron have a great influence on mechanical properties, such as the tensile strength UTS. In this case, the key is to know the value of the degree of undercooling ΔT. The type of inoculant used affects the ΔT value. The study related the number of N primary austenite grains with the degree of undercooling ΔT and the tensile strength UTS with the number of primary austenite N grains.

CREEP RUPTURE LIFE OF PRE-STRAINED SUPERALLOY N07080

The creep of the pre-strained superalloy N07080 is described in this work. The pre-strain was achieved by warm rolling at 1050 oC.-The warm rolling was performed due to additional strengthening, i.e increasing of the superalloy hardness.-The pre-strain drastically reduces the creep rupture life of the superalloy compared to the creep rupture life of the standard heat treated superalloy.-The drastic reductionof the creep rupture life is result of rapid creep cavity nucleation on stress concentration sites along primary grain boundaries of the pre-strained superalloy.-Recrystallization eliminates potential sites for rapid cavity nucleation and prolongates the creep rupture life.

Determining on welding methods and parameters for the 3%Ni steel welded joints-insights into the corrosion resistance of the fusion zone

Through exposing the 3%Ni (wt. %) steel welded joints in a tropical marine environment, the effects of welding methods and the corresponding parameters on the corrosion resistance of fusion zone (FZ) were investigated in detail. Results indicated that the microstructures of FZ were mainly composed of more finer primary austenite grains for welded joint made by CO2 gas metal arc welding (GMAW), compared with shielded metal arc welding (SMAW) and automatic submerged arc welding (SAW), which resulted in more uniform Volta potential distribution on FZ (0.02–0.21 V for GMAW, 0.37–0.64 V for SMAW, −1.21–1.2 V for SAW). The uniform corrosion morphology facilitated by the fine primary austenite grains on GMAW FZ improved the combination of the rust layer on matrix, presenting highest corrosion potentials after exposure tests (Ecorr = −577 mV for one year and −408 mV for two years). The rust layer formed on GMAW FZ contained more amorphous substance and presented better corrosion protectiveness (α/γ = 1.36) compared with other two welding processes (0.86 for SMAW and 0.75 for SAW), which was attributed to the electrode welding materials with fine diameter (1.2 mm) and the moderate welding heat input (14.5–15 kJ/cm) for GMAW.

High temperature fluid-rock interaction recorded in a serpentinized wehrlite from eastern Singhbhum Craton, India: Evidence from mineralogy, geochemistry and in situ trace elements of clinopyroxene

A N-S trending, lenticular, and dismembered ultramafic unit is found emplaced within the multiply deformed metapelites of the North Singhbhum Mobile Belt, belonging to the Singhbhum Craton, eastern India. Their occurrence in an orogenic belt, lack of evidences of intrusive activity and close proximity to the Singhbhum Shear Zone suggest emplacement by thrust control. These rocks have experienced extensive serpentinization which has obscured and obliterated some of the features of the protolith. Relict areas of the Bangriposi wehrlite rocks indicate that the protolith might have been a cumulate clinopyroxene-dunite/wehrlite from an oceanic magma chamber. Detailed petrography and mineralogy reveal numerous metasomatic features which are separate from the serpentinization event: (i)Very high Ni-content of the relict olivines which does not correlate with Fo contents, (ii) Presence of secondary clinopyroxene (Cpx2) rims around primary olivine and replacing primary clinopyroxene (Cpx1), which have major and trace element compositions similar to clinopyroxenes from diopsidites of crustal origin (iii) Occurrence of secondary calcic hornblendes as tiny blebs within the Cpx2 rims (iv) Occurrence of secondary Mg-chlorite as interstitial patches between olivine rimmed by Cpx2 and inter-mixed with antigorite in the matrix, (v) Modifications of original Cr-spinels to ferri-chromite cores rimmed by magnetite. These features indicate these rocks have experienced fluid-rock interaction at temperatures above the serpentinization process. Primary Cpx1 grains exhibit elevated LREE compositions and can either reflect effects of cryptic metasomatism or crystallization from an enriched melt. Both groups of clinopyroxenes exhibit LILE enrichment and HFSE depletion. P-T estimates from Cpx1 and Cpx2 yield values of ~1200 °C and 0.5–1.2 GPa. The calcic hornblendes provide more realistic estimates of ~1000 °C and ~ 1.0 GPa, which suggest that the Cpx2 + hornblende assemblage formed during high temperature fluid-rock interaction. Presence of interstitial chlorite, chlorite+antigorite in the matrix and Cr-spinel recrystallization suggests successively decreasing temperatures during the fluid-rock interaction episode. Modeled trace element characteristics of fluids which are supposed to be in equilibrium with Cpx2 show similarities with high-temperature, ore-forming basinal brines. Similar basinal brines formed Cu-U ores in the Singhbhum Shear Zone and was likely the metasomatic agent of the Bangriposi wehrlite rocks. These rocks were originally cumulate ultramafic units from an oceanic crustal magma chamber, which experienced prolonged fluid-rock interaction in a retrogressive regime, until its emplacement as a dismembered unit in an orogenic belt.

High-Temperature Deformation Behaviors of the C-Doped and N-Doped High Entropy Alloys

High entropy alloys (HEAs) containing multi-principal metallic constituents have attracted much attention. A good understanding of their hot-deformation behavior and recrystallization mechanism is the prerequisite for microstructures tuning and for optimizing mechanical performance. Here, the flow behavior and recrystallization mechanism of the N-doped and C-doped face-centered cubic phase HEAs are produced at high temperatures by hot-compression at 1123–1273 K, with strain rates of 0.1–0.001 s−1. Constitutive equations were successfully constructed to reveal flow behavior, and stress-strain curves were predicted using strain compensated polynomial functions. Discontinuous and continuous dynamic recrystallization proceeded concurrently when compressed at a low temperature and high strain rate, whereas discontinuous recrystallization, which occurs at primary grain boundaries, became predominant at a high temperature and low strain rate, significantly contributing to the refinement and homogenization of the grains. For this reason, a relatively high temperature and a low strain rate, in which the recrystallized grains exhibit equiaxed morphology and very weak texture, are more suitable for refining grains. The average size of the grains was approximately 10 μm. This study sheds light on grain optimization and mechanical properties through thermomechanical processing.

Microbial Volatile Organic Compounds from Tempered and Incubated Grain Mediate Attraction by a Primary but Not Secondary Stored Product Insect Pest in Wheat

There has been a dearth of research elucidating the behavioral effect of microbially-produced volatile organic compounds on insects in postharvest agriculture. Demonstrating attraction to MVOC’s by stored product insects would provide an additional source of unique behaviorally-relevant stimuli to protect postharvest commodities at food facilities. Here, we assessed the behavioral response of a primary (Rhyzopertha dominica) and secondary (Tribolium castaneum) grain pest to bouquets of volatiles produced by whole wheat that were untempered, or tempered to 12%, 15%, or 19% grain moisture and incubated for 9, 18, or 27 days. We hypothesized that MVOC’s may be more important for the secondary feeder because they signal that otherwise unusable, intact grains have become susceptible by weakening of the bran. However, contrary to our expectations, we found that the primary feeder, R. dominica, but not T. castaneum was attracted to MVOC’s in a wind tunnel experiment, and in a release-recapture assay using commercial traps baited with grain treatments. Increasing grain moisture resulted in elevated grain damage detected by near-infrared spectroscopy and resulted in small but significant differences in the blend of volatiles emitted by treatments detected by gas chromatography coupled with mass spectrometry (GC–MS). In sequencing the microbial community on the grain, we found a diversity of fungi, suggesting that an assemblage was responsible for emissions. We conclude that R. dominica is attracted to a broader suite of MVOC’s than T. castaneum, and that our work highlights the importance of understanding insect-microbe interactions in the postharvest agricultural supply chain.

Morphology genetic 3D hierarchical SnO2 microstructures constructed by Sub 5 nm nanocrystals for highly sensitive ethanol-sensor

SnO2 is widely used for ethanol-sensing applications due to its excellent physicochemical properties, low toxicity and high sensitivity. However it is a challenge to construct 3D-hierarchical structures with sub 5 nm primary grain particle, which is the optimized size for ethanol sensor. Herein, genetic tri-level hierarchical SnO2 microstructures are synthesised by the genetic conversion of 3D hierarchical SnS2 flowers assembled by ultrathin nanosheets. The SnS2 nanosheets are morphology genetic converted to porous nanosheets with sub 5 nm SnO2 nanoparticles during the calcination process. When used for the detection of ethanol, the sensor exhibits a high sensitivity of 0.5 ppm (R a/R g = 6.8) and excellent gas-sensing response (R a/R g = 183 to 100 ppm) with short response/recovery time (12 s/11 s). The excellent gas sensing performance is much better than that of the previous reported SnO2-based sensors. The highly sensitivity is attributed to the large surface area derived from the recrystallization and volume changes, which offers more active sites during the morphology genetic conversion from SnS2 to SnO2. Furthermore, the flower-like 3D structure enhances the stability of the materials and is beneficial for the mass diffusion dynamics of ethanol.

Controllable mechanical anisotropy of selective laser melted Ti6Al4V: A new perspective into the effect of grain orientations and primary grain structure

This work investigated the significantly weakened anisotropy of tensile properties of selective laser melted Ti6Al4V by heat treatment and represented a new perspective into the weakening mechanism. For the as-deposited sample, the tensile strength showed an evident improvement as the oriented angle θ (the angle between the tensile axis and the substrate plane) increased from 0° to 90° while the elongation showed the opposite trend. Nevertheless, the heat treatment weakened the anisotropy of strength as the deviation was reduced from 167 to 39 MPa, while the anisotropy of ductility was also remarkably declined. An algorithm, based on the EBSD data, was newly adopted to determine the most likely active slip system of each grain and evaluate the area-weighted average Schmid factors (SFs). The statistical results presented the distinct difference in the SFs of the as-deposited sample as θ changed while the SFs of the heat-treated sample showed similar values, quantitatively explaining the anisotropy of strength and the weakening mechanism. Besides, the high dependence of SF on the primary β grains, the number of primary β grains in the tensile specimen at different θ, and the existence of equiaxed grain boundary α together explained that ductility was worst at θ = 90° and increased as θ decreased.

Anisotropic tensile behaviour of additively manufactured Ti-6Al-4V simulated with crystal plasticity

The anisotropic behaviour of laser powder bed fusion (LPBF) Ti-6Al-4V under uniaxial tension is investigated through crystal plasticity simulations. A periodic multi-scale representative volume element (RVE) is calibrated against quasi-static tensile tests carried out on dog-bone specimens, printed in different orientations. This fitting procedure results in an anisotropic crystallographic texture and a minimum set of crystal plasticity constitutive parameters which are able to reproduce the experimental behaviour. The synthetic RVE consists of primary grains with a realistic aspect ratio and an internal lamellar structure, that approximates the α′ martensite microstructure observed in micrographs of as-built Ti-6Al-4V. The Young’s modulus, yield strength, and hardening behaviour observed experimentally, could be precisely captured using a very limited number of model parameters. Thereby, this work contributes to a deeper understanding of the interplay between micro-structure and macroscopic behaviour, and with a new set of crystal plasticity parameters specific for α′ dominated LPBF Ti-6Al-4V.

Insecticidal Effect of Eucalyptus Essential Oils on Mortalities of Storage Pests of Grains Sitophilus oryzae and Sitophilus granarius in the Region of Tissemsilet Algeria

Background: Stored cereals are attacked by pests including Sitophilus, a primary insectpestthat kthe whole grain and destroys the germ. The usual control methods are less efficient and more expensive. The use of essential oils of aromatic plants is more interesting. Eucalyptus is a plant of great medicinal value due to the presence of secondary metabolites. Methods: In this experimentation that took place during the year 2017, extraction of oils by hydro distillation of eucalyptus was used on insects at different doses by two methods with are ingestion and inhalation. Two species of Sitophylus are morphologically different as they may be different with regard to the use of biopesticide (eucalyptus essential oil), regarding the mortality rate in relation to the duration of treatment Result: Sitophilus oryzae was more sensitive to this bio-pesticide since it was only after eight (08) hours of treatment that mortality exceeded 50% by the ingestion method whereas only 6.6% of mortality was recorded on Sitophilus granarius. Same observation by the inhalation method, 90% mortality on the third day for Sitophilus oryzae while only 20% mortality on Sitophilus granarius. So the ingestion method requires fewer products plus a speed in the mortality time.

Porosity measurement of granular rock samples by modified bulk density analyses with particle envelopment

Interest in assessing the extent of “isolated” pores in the total (both effective and “isolated”) porosity of tight rocks has increased in recent years due to the development of unconventional shale reservoirs. Porosity measurements of crushed granular and whole rock samples can be used to assess the proportion of “isolated” pores in the total porosity, which will help with reservoir characterization and understanding petroleum production. This study aims to measure the porosities of granular samples by independent measurements of bulk density (i.e., the density of the matrix and pore space combined) and particle density (i.e., the density of the matrix alone) provided by a modified bulk density method and helium pycnometry. The modified bulk density method uses quartz powder (<75 μm) to substitute for the original larger- and uniform-sized DryFlo of the GeoPyc 1365 method to measure the intra-granular density of granular rock samples in the size range 75–850 μm, thereby extending the sample size range for bulk density analyses of granular samples to 75–8000 μm. Using four rock samples as examples, the bulk density and particle density of crushed Woodford Shale (two samples with different pore connectivity), Paluxy Sandstone, and Austin Chalk were measured for the porosity calculation and assessment of “isolated” pores. The results show that (1) the modified bulk density measurement of granular crushed-rock could provide semi-quantitative results with acceptable repeatability and reproducibility between samples (of the same rock at different particle sizes or rocks of different origins), and (2) the changes in effective porosity as a function of sample size are related to the primary grain size for well-connected sandstone and chalk, and the extent of “isolated” pores for shales with poor pore connectivity.

Nonclimatic and extrabasinal processes controlled pedogenesis in paleosols of the Paleocene Nacimiento Formation, New Mexico, USA

AbstractPaleosols can represent intervals of nondeposition in sedimentary packages and are used with increasing frequency as proxies for paleoenvironmental conditions during basin filling. However, the complexities of factors both internal and external to pedogenesis require consideration of paleosols in any basin or sedimentary package in a broader context than is often assumed. With this in mind, we measured and analyzed pedogenic features, stratigraphic position, geochemical composition, and petrography of paleosols in the Nacimiento Formation to gain insight into the paleoenvironmental conditions of the early Paleocene in the San Juan Basin. During this interval, the San Juan Basin was located in middle northern latitudes (~40°N) and saw rapid terrestrial siliciclastic sedimentation related to Laramide tectonism. Evidence from earlier researchers suggests that prevailing climate conditions during Nacimiento Formation deposition were warm and humid. We used morphological properties of paleosols to categorize paleosols into pedotypes indicative of distinct pedogenic conditions. The general stratigraphic distribution of these pedotypes shows an up-section increase in soil drainage conditions through the Nacimiento Formation that cannot be correlated with known climate changes. We suggest that fluvial system evolution was the major control on pedogenic conditions. We investigated Nacimiento Formation paleosols with widely used paleosol geochemical climate analyses, which provided paleoclimate estimates that are in disaccord with independently derived estimates. We show that in alluvial depositional systems with source areas in weathered sedimentary rocks, these analyses can be difficult to interpret and likely lead to estimates that do not reflect true pedogenic conditions during the postdepositional near-surface alteration of sediments. Petrographic analysis of Nacimiento Formation paleosols showed that some likely formed under semiarid to subhumid conditions that allowed pedogenic accumulation and illuviation of smectite clays yet did not substantially chemically alter primary detrital plagioclase feldspar grains in paleosol B horizons. The paleosols of the Nacimiento Formation, when analyzed at the basin scale, show that sedimentary aggradational processes can overpower climate processes in creation of a sequence of paleosols in a stratigraphic section. In addition, the incorporation of clays from sedimentary rocks in a basin's source area can drastically skew the geochemical signatures and therefore interpretations of paleosols in that basin.

In situ chemical and isotopic analyses and element mapping of multiple-generation pyrite: Evidence of episodic gold mobilization and deposition for the Qiucun epithermal gold deposit in Southeast China

Abstract Gold deposits are often the result of complex mineralization and remobilization processes. Interpretation of bulk geochemical and sulfur isotope data of the gold deposits is frequently hampered by complex zoning in pyrite, which calls for in situ determination of geochemical and sulfur isotope composition of sulfide minerals. The Qiucun deposit is a good representative of epithermal gold deposits in the Mesozoic Coastal Volcanic Belt of southeastern China. It represents a complex mineralization history, comprising three hydrothermal stages: (I) early stage of pyrite-quartz-chalcedony; (II) main ore stage of quartz-polymetallic sulfide; and (III) post-ore stage of quartz-carbonate. Detailed backscattered electron imaging (BSE) and in situ trace element and sulfur isotope analyses using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) and LA-multicollector (MC)-ICP-MS were applied to reveal the gold mineralization and remobilization history of this deposit. Four texturally distinct generations of pyrite were identified, all of which host invisible gold: Py1a and Py1b in Stage I and Py2a and Py2b in Stage II. A detailed study of the texture, chemistry, and sulfur isotopic composition as well as hydrothermal evolution of auriferous pyrite from the Qiucun deposit revealed the behavior of gold in the course of pyrite evolution. Pyrite of Stages I and II contains invisible gold, whereas later-stage visible native gold and re-enrichment in invisible gold is associated with alteration rims around the primary pyrite grains. Py1a is rich in silicate inclusions, enriched in Co and Ni, and depleted in As and Au relative to later pyrite generations. This redistribution is attributed to the alteration of biotite in the sub-volcanic host rocks that effectively destabilized gold in the ore fluid during Py1a deposition. Py1b and Py2a show oscillatory zoning with bright bands having elevated As and Au contents. The oscillatory zoning is interpreted to reflect pressure fluctuations and repeated local fluid boiling around the pyrite crystals. These three pyrite generations (Py1a, Py1b, Py2a) record a narrow range of δ34SV-CDT values between –3.6 and 4.6‰, consistent with a magmatic sulfur source. Gold and some trace elements (As, Ag, Sb, Pb, Tl, and Cu) that were initially incorporated into Py2a became partially exsolved and remobilized during the replacement of porous and invisible gold-rich Py2b. This replacement was likely due to coupled dissolution and re-precipitation reactions triggered by oxidation of the mineralizing fluids. Fluid oxidation is further supported by a general decrease trend of δ34SV-CDT from Py2a (–3.2 to 4.6‰) to Py2b (–15.2 to –2.3‰). Last, previously formed auriferous pyrite underwent post-mineralization fracturing, causing local pulverization of pyrite. Thus, newly created porosity facilitated fluid circulation, hydrothermal alteration of the pyrite, and remobilization of invisible gold, which re-precipitated with pyrite in the form of electrum as small inclusions or as larger grains within fractures. Our study emphasizes that pressure-driven hydrothermal processes play a vital role in the initial enrichment and re-concentration of gold and some other trace metals during episodic deposition, replacement, and hydrothermal alteration of gold-bearing pyrite in epithermal gold deposits, ultimately forming visible gold and high-grade ore shoots as exemplified by the Qiucun deposit.

Control of variability of primary grain assemblages on the stratigraphic differences in diagenetic processes and products in organic-rich sediments

Diagenesis exerts a key control on the evolution of mineralogical systems in shales, and by extension, on the development of rock properties amenable to unconventional reservoir prospectivity. To develop an understanding of the control of primary grain assemblage on the diagenetic pathways and products in shales, integrated high-resolution petrographic and multiple geochemical studies were conducted on samples from a vertical transect of oil-gas mature (vitrinite reflectance ranging from 0.98 to 2.72%) Whitehill Formation, a shale unit identified as the main potential gas reservoir in South Africa. Results show that the formation comprises three intervals with contrasting primary grain assemblages, including organic matter content, maceral type, and detrital mineral grains, as well as the submillimeter-scale arrangement of these constituents. The lower interval occurs as parallel-laminated black shale dominated by components derived from primary production, such as Tasmanites cysts, colonial algae, radiolarian tests, and amorphous organic matter with up to 5.78% TOC, and depleted in siliciclastic detritus. The mid and upper intervals contain biologically produced components (up to 16.57% TOC) and high quantities of siliciclastic mud dominated by clay minerals and micas, and are organized into thick discontinuous gray laminae. Petrographic data suggest that the high organic content supported a variety of bacterial metabolic pathways, which caused the precipitation of mineral cements in the sediment pore spaces prior to compaction. However, the early diagenetic reactions and products in these intervals display systematic variations that reflect heterogeneity in their primary grain assemblages. The presence of framboidal pyrite throughout the lower interval suggests sulfate reduction as the predominant metabolic pathway. In absence of significant volumes of siliciclastics, the acidity associated with this process was poorly buffered, and the pore waters were reducing. These conditions led to the dissolution of opaline radiolarian tests, which recrystallized within Tasmanites cysts and interstitial pores to quartz. On the contrary, carbon isotopes indicate that organic oxidation in the mid and upper sections was mainly promoted by methanogenic archaea and that the associated acidity was effectively buffered by the detrital aluminosilicates. The resulting bicarbonate alkalinities allowed for the formation of interstitial carbonate cements (dolomite, calcite). Aluminum released during the acid-consumption reactions recrystallized within sheltered and interstitial pores to chlorite. Considering that many other shale successions exhibit similar stratigraphic variability of primary grain assemblages as the Whitehill Formation, this type of study will improve the characterization of shale mineralogical systems and bulk properties amenable to sustainable unconventional exploration.

Combining Traditional Taxonomy and Metabarcoding: Assemblage Structure of Nematodes in the Shelf Sediments of the Eastern Antarctic Peninsula

This study provides a snapshot of the largely understudied meiobenthic and nematode communities in the Prince Gustav Channel (PGC) and Duse Bay (DB). We compared five stations sampled at different water depths along the shelf and investigated their meiobenthic community structure. We approached nematode biodiversity combining traditional taxonomic identification and high throughput sequencing (HTS), with the use of Amplicon Sequence Variants (ASVs). Additionally, we characterized the environment by primary production proxies, grain size and seasonal ice conditions. Our results suggest that the availability of organic matter and its freshness are responsible for the high densities found at all depths. However, potential factors influencing the high local and regional variability of meiofauna density and biodiversity are less clear. A bathymetric transect consisting of three stations in DB (200, 500, and 1,000 m depth) showed increasing pigment concentrations in the first centimeters of the sediment vertical profile with increasing water depth, whereas the meiofauna densities showed the opposite trend. The deepest station of DB seems to function as a sink for fine material as supported by the higher silt fraction and higher organic matter concentrations. When comparing the two basins in the PGC (1,000 and 1,250 m) and the one in DB (1,000 m), differences in terms of environmental variables, meiofaunal densities, and composition were observed. The deepest basin in PGC is located further South (closer to the highly unstable Larsen area), and marked differences with the other basins suggest that it might be experiencing different conditions as a result of its presence near the summer ice margin and its more elongated topography. Both, the shallowest and the deepest stations showed the highest number of unique sequences, suggesting a more biodiverse nematode assemblage. The morphological identification did not show significant differences in the biodiversity of all stations, differently from the ASVs approach. However, the lack of reference sequences in online databases and the thickness of nematode’s cuticule are still important issues to consider as they potentially lead to underestimations of biodiversity and functional traits.

Dietary soluble non-starch polysaccharide level and composition influences grower and finisher phase performance, excreta moisture content and total tract nutrient digestibility in broilers

ABSTRACT 1. The aim of this study was to examine the impact of dietary soluble non-starch polysaccharide (sNSP) level and composition on grower and finisher phase performance, total tract nutrient digestibility and excreta moisture content in broiler chickens. 2. Cobb 500 broilers (n = 1080) were fed 12 dietary treatments; four diets with differing primary grain sources (barley, corn, sorghum and wheat) and three different sNSP levels (low, medium and high). Diets were formulated to have similar protein and energy levels but differing sNSP levels, induced by manipulating the quantity of the ingredients in the diet. The diets were fed in three phases, starter (d 0–12), grower (d 12–23) and finisher (d 23–31). 3. For birds aged d 23 and 31, total pen body weight and feed intake were determined, and fresh excreta and litter samples were collected per pen. Dry matter (DM) content was measured in the excreta and litter samples. Total tract DM digestibility, apparent metabolisable energy corrected to nitrogen (AMEn), and soluble and insoluble NSP and free oligosaccharide degradability were evaluated. 4. In birds fed the sorghum- and corn-based diets, feeding high sNSP resulted in a lower cFCR at d 0–23 compared to low sNSP (P = 0.004 and P = 0.044, respectively). In birds fed the corn-based diet, feeding low sNSP resulted in the lowest litter DM but highest DM digestibility at d 23 (P = 0.045 and P < 0.001) and d 31 (P = 0.022 and P = 0.008). For all diets, degradability of sNSP was higher and insoluble NSP was lower when feeding low compared to high sNSP (P < 0.001). In birds fed the barley- and sorghum-based diets, AMEn was lower when feeding the low compared to high sNSP level (P < 0.001 and P = 0.016, respectively). 6. Results from this study showed that level of dietary sNSP impacts broiler productive performance and nutrient utilisation.

PETROGRAPHIC CHARACTERIZATION AND DIAGENESIS IN SANDSTONES OUTCROPS OF THE NORTHERN MACEIÓ FORMATION: IMPLICATIONS IN RESERVOIR QUALITY

The acquisition of geological data is of fundamental importance for the study of areas potentially relevant to the occurrence of petroleum systems. In this context, the development of research in outcropping rock formations has proven to be a potential method to investigate the geology of the geological unit studied in subsurface. One of several examples found in Brazil are the outcrops Barreiras do Boqueirão and Praia de Japaratinga, belonging to the Maceió Formation, located in the northern coast of Alagoas State. The Maceió Formation has the lowest cretaceous sedimentation record within the Alagoas Basin. This sedimentation, present almost in the entire basin, is located mainly in its subsurface. This geological unit is composed of several lithologies, including a turbiditic sequence predominantly formed by shales, sandstones and conglomerates. This environment makes it possible the occurrence of a petroleum system. Our research group chose to investigate this environment because turbiditic sandstones are excellent petroleum reservoirs, and they have a great economic relevance in the Brazilian petroleum scenario. To develop this research, a petrographic characterization of the Maceió Formation sandstones was conducted to help determine the compositional and diagenetic aspects of these rocks and infer the influence of diagenetic processes on the quality of these sandstones as reservoirs. The petrographic analysis showed that the studied sandstones can be classified as arkose and quartzenite, present moderate porosity and good permeability, observed through the predominant presence of floating contacts between the grains. The porosity is predominantly primary intergranular, averaging 15%, but secondary porosity by fracture and dissolution of primary grains also occurs. The sandstones of the Maceió Formation are poorly and moderately selected, with angular, sub-angular and sub-rounded grains, showing low to medium textural maturity, which may also influence the quality of the reservoir, impairing the primary porosity in the samples. The three diagenetic stages were identified as: eodiagenesis, mesodiagenesis, and telodiagenesis. The diagenetic processes found were: mechanical compaction, beginning of chemical compaction, clay infiltration, pyrite cementation, grain dissolution, chlorite cementation, quartz sintaxial growth, and mineral alteration and replacement. Mineral replacement was a phenomenon observed quite expressively in the samples analyzed. This event was evidenced, particularly, by the substitution of muscovite and feldspar for kaolinite, the alteration of biotite was also identified in the samples. Therefore, one can infer that the diagenetic processes had little influence on the reduction of the original porosity in the samples studied. In general, considering all the analyses performed in this research, one can see that the sandstones of the Maceió Formation (northern portion) present a good reservoir quality.

Effect of nanoparticles on morphology and size of primary silicon and property of selective laser melted Al-high Si content alloys

The coarsening of primary silicon phases is one of the main challenges in the preparation and application of Al-high Si content alloys. In this work, AlSi40 alloys were manufactured by selective laser melting (SLM). The influence of ceramic nanoparticles on the morphology and size of primary Si phase(s) is investigated. With addition of ceramic nanoparticles, large snow-shaped primary Si changes towards a polygonal shape in coarse regions, while blocky primary Si in fine regions shows insignificant change. The size of primary Si in the modified alloy decreases by ~27.1% and ~25.2% in the respective coarse and fine regions compared to that of the unmodified alloy. Due to the refinement and smoothening of primary Si in the modified alloy, the microhardness distribution becomes homogeneous and an average value of ~233 HV0.2 was obtained. The coefficient of friction (COF) value and the wear rate are ~0.44 and ~4.5 × 10−5 mm3N−1m−1, respectively. An ultimate compressive strength of ~0.76 GPa and a maximum compressive strain of ~7.99% are obtained, increasing by ~21.0% and ~18.0% compared to those of the unmodified alloy. The SLM-fabricated AlSi40 alloys upon heat treatment showed an improved plasticity and slightly decreased strength due to the coarsening of primary Si and grains, decreased solid solution of Si in the matrix as well as accommodation of residual stresses after heat treatment.

Grain boundaries contribute to highly efficient lithium‐ion transport in advanced LiNi0.8Co0.15Al0.05O2 secondary sphere with compact structure

AbstractLiNi0.8Co0.15Al0.05O2 (NCA) secondary particles with high tap density have a great potential for high volumetric energy density lithium (Li)‐ion power battery. However, the ionic conductivity mechanism of NCA with compact structure is still a suspense, especially the function of grain boundaries. Herein, we systematically investigate the Li‐ion transport behavior in both the primitive NCA (PNCA) secondary sphere densely grown by single‐crystal primary grains and ball‐milled NCA (MNCA) nanosized particle to reveal the role of grain boundaries for Li‐ion transport. The PNCA and MNCA have comparable Li‐ion diffusion coefficients and rate performance. Moreover, the graphene nanosheet conductive additive only mildly affects the Li‐ion diffusion in PNCA cathode, while which severely blocks the Li‐ion transport in MNCA cathode. Through high‐resolution transmission electron microscopy and electron energy loss spectroscopy, we clearly observe Li‐ion depletion at lower state of charge (SOC) and Li‐ion aggregation at high SOC along the grain boundaries of PNCA secondary particles during high‐rate lithiation process. The grain boundaries can construct an interconnected Li‐ion transport network for highly efficient Li‐ion transport, which contributes to excellent high‐rate performance of compact PNCA secondary particles. These findings present new strategy and deep insight in designing compact materials with excellent high‐rate performance.

Effects of Secondary-Phase Formation on the Electrochemical Performance of a Wire Arc Additive Manufactured 420 Martensitic Stainless Steel under Different Heat Treatment Conditions.

This study aims to investigate the effects of annealing, quenching, and tempering (Q&T) heat treatments on the microstructure, crystallographic orientation, and electrochemical performance of a wall shaped 420 martensitic stainless steel part fabricated by wire arc additive manufacturing technology. The formation of a martensitic matrix with delta ferrite in the as-printed sample, islands of spherical chromium carbides embedded in a ferritic matrix in annealed sample, and intergranular chromium-rich carbides along the primary austenite grain boundaries in addition to intra-lath Fe-rich carbides in the quenching and tempering heat treated sample were detected. To characterize the corrosion performance of the fabricated samples, open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy tests were performed on all samples in aerated 3.5 wt.% NaCl electrolyte at room temperature. The corrosion morphology of the as-printed sample was characterized by localized corrosion attacks adjacent to the delta ferrite phase, while severe pitting occurred in the annealed sample due to the high susceptibility of ferritic matrix-carbide interface to pitting. In contrast to the as-printed and annealed sample, the electrochemical performance of the quenched and subsequently tempered samples was found to be significantly improved, ascribed to elimination of the chromium depleted regions adjacent to the delta ferrite phase, and enhanced protectiveness of the passive film on the alloy’s surface.