Mineral Changes Research Articles

Effects of Compressive Stress on Carbonation-Induced Degradation of Oil Well Cement under CO<sub>2</sub> Storage Environment

This paper presents an experimental study to investigate the effects of compressive stress during the CO2 attack on wellbore cement under carbon capture and storage (CCS) conditions. Oil well cement samples were designed to be exposed to humid supercritical CO2 gas and CO2-saturated brine and simultaneously subjected to external compressive stresses with load levels of 0, 25%, 50%, and 75% of the ultimate compressive strength. Morphology changes were determined using phenolphthalein dye testing and scanning electron microscopy. Mineral changes were detected by X-ray diffraction. Relative compressive strength and gas permeability of exposed cement were analyzed. It is shown that the 25% stress level has little effect on degradation of cement while the applied compression load up to 50% increased the compactness of cement and finally slowed down the degradation rate. In contrast, a much higher compressive stress level up to 75% facilitated the generation and propagation of micro-cracks. The stress induced micro-crack finally caused a surge in CO2-rich fluids and then significantly accelerated the degradation rate of oil well cement. Findings from this study expanded the understanding of the integrity of oil well cement for CCS wells.

Temperature and moisture driven changes in soil carbon sequestration and mineralization under biochar addition

Sequestering more carbon in soil is an effective approach to mitigate climate change. The temporal variability of soil organic carbon (SOC) that reflects its loss and accumulation potential is important to model SOC sequestration under climate change, but it is still poorly understood under biochar addition. To identify the temporal variability of SOC, induced by climate conditions (i.e. precipitation and temperature) under biochar addition, a field experiment with the biochar addition rates of 0 (CK), 1.8 (BL), 3.6 (BM), and 7.2 (BH) mega gram (Mg) ha−1 yr−1 and a laboratory incubation under controlled conditions at 20, 40, and 70% moisture under 10 and 20 °C in CK and BH soils was conducted. The results showed that biochar addition increased average annual SOC sequestration rates by 31.8–47.8% (369.8–556.6 kg ha−1 yr−1), and led to higher stock compared with CK. However, the annual sequestration rates of biochar addition showed a decreasing trend from 2014 (0.8–4.0 Mg ha−1 yr−1) to 2018 (−7.1 to −3.5 Mg ha−1 yr−1), and BH had the lowest sequestration rate from 2017 to 2018 compared with CK. Because the coefficients of variation of SOC concentration under biochar addition (1.2–11.0%) were significantly higher than those of CK (0.8–2.9%), indicating that biochar enhanced the temporal variability of SOC. The incubation study also confirmed that higher temporal variability under biochar addition resulted from increased sensitivity of SOC mineralization to temperature at 0–10 cm and to moisture at 10–20 cm layer. The high temporal variability was not conducive to the rates of carbon inputs retention in soil, and BH decreased by 20.4% compared with CK. Therefore, higher temporal variability induced by biochar addition constrains the potential for SOC sequestration, and middle and low rates (1.8–3.6 Mg ha−1 yr−1) of biochar addition are promising and cost-effective options in the North China Plain.

Imaging with radiolabelled bisphosphonates.

Radiolabeled bisphosphonates were developed in the 1970s for scintigraphic functional imaging of the skeleton in benign and malignant disease. Tracers such as 99mTc-methylene diphosphonate, that map focal or global changes in mineralization in the skeleton qualitatively and quantitatively, have been the backbone of nuclear medicine imaging for decades. While competing technologies are evolving, new indications and improvements in scanner hardware, in particular hybrid imaging (e.g. single photon emission computed tomography combined with computed tomography), have allowed improved diagnostic accuracy and a continued role for radiolabeled bisphosphonate imaging in current practice.

Changes in soil carbon mineralization, soil microbes, roots density and soil structure following the application of the arbuscular mycorrhizal fungi and green algae in the arid saline soil

Evaluation of the potential mechanisms that link arbuscular mycorrhizal fungi (AMF) and green algae to carbon mineralization is highly fundamental under saline arid land since a deep vision into these interrelationships might lead to improvements in soil quality, carbon protection and the implication for a better ecosystem functioning. This study aimed to determine the interactions between arbuscular mycorrhizal fungi (Glomus mosseae), algal biomass (chlamydomonas sp) and subsequent effects on carbon mineralization, bacterial biomass carbon, soil pH, roots density, large macroaggregates (>2000 μm), small macroaggregates (250–2000 μm) and microaggregates (53–250 μm) in maize crop. The general nature of the results that were significant and what they mean is sufficient. Overall, results showed that the combination of AM fungi with algae was effective and provoked carbon decomposition and soil aggregates formation by lowering pH and boosting bacterial biomass C as well as roots density which can be beneficial to soil ecology through the enhancement of the soil bio-characteristics and the potential for the corn growth promotion in the arid saline soil.

Nitrogen mineralization of legume residues: interactions between species, temperature and placement in soil

Aim of study: To assess the interactive effects of legume species, residue placement and temperature on the net nitrogen (N) mineralization dynamics in a sandy loam soil.Area of study: Northern PortugalMaterial and methods: Cowpea (Vigna unguiculata L. Walp), faba bean (Vicia faba L.) and pea (Pisum sativum L.) residues were incorporated or applied to the soil surface at typical field yields in Europe and incubated in aerobic conditions for up to 240 days, either at 10ºC or 20ºC. Initial chemical characteristics of the soil and residues were determined. Net N mineralization was estimated at eight time intervals.Main results: Cowpea residues caused no negative changes in soil mineral N contents and were able to release the equivalent of 21-45 kg N ha-1 in 240 days. Net N immobilization (up to 17 kg N ha-1) was observed throughout most of the trial in soil with faba bean and pea residues. Differences in mineralization patterns could be attributed to the higher quality (lower carbon to nitrogen (C:N) ratios) of cowpea. Surface placement increased net N mineralized by as much as 18 kg N ha-1. The sensitivity of N mineralization to changes in temperature and residue placement varied with legume species, likely due to effects associated with differences in C:N ratios.Research highlights: Adding cowpea residues to soil is suitable when high N availability is immediately required. Faba bean or pea residues are better suited for conservation of soil N for later release.

Evaluation of the effect of fluorinated tooth bleaching products using polarized Raman microscopy and particle induced gamma-ray emission.

In this in vitro study, the effect of the application of tooth bleaching products in human enamel was evaluated using polarized Raman microscopy, particle induced gamma-ray emission (PIGE) and Vickers Hardness test. Due to their acidic nature, teeth whitening products are associated with changes in enamel mineralization. Consequently, products have appeared in the market that promote the incorporation of fluorine in order to decrease the solubility of the hydroxyapatite in enamel and prevent demineralization. This way, four commercial products with different active principle concentrations: 16% carbamide peroxide (Opalescence PF® and VivaStyle®) or 6% hydrogen peroxide (Opalescence Go PF® and VivaStyle Paint On®) and presence or not of fluorine were compared. The information on the crystalline state of the enamel was provided by the determination of the depolarization ratio of the symmetric stretching band of phosphate (at 959cm-1). Furthermore, the content and uptake of F was evaluated using PIGE in the two fluorinated products as well as in one negative control group. In order to evaluate the microhardness of enamel by means of Vickers test, another group of polished samples was prepared (using Opalescence PF®) and evaluated. Conversely to what could be expected, the obtained results determined a statistically significant decrease of depolarization ratio, leading to an increase of mineralization after the application of the bleaching products, except for VivaStyle®. For this group, no significant variation was obtained before-after treatment, most likely due to the acidity of the product (pH=5.8). Additionally, an increase of concentration of F in the dental tissues was determined for the fluorinated products. On the other hand, enamel polishing, required for the application of the Vickers test, led to increased susceptibility to erosion, resulting in decreased hardness and an increased enamel depolarization ratio.

The influence of multiple combined chemical attack on cast-in-situ concrete: Deformation, mechanical development and mechanisms

In this paper, a laboratory program was performed to investigate the influence of combined internal chloride and external sulfate/magnesium simulated exposure on cast-in-situ OPC concrete samples. Specimens of cylinder shape were prepared and then stored in distilled water or aggressive solutions, which were sulfate or sulfate-magnesium solutions. The specimen parameters, such as diameter increments, mass increments, unconfined compression strength together with sulfate concentration, were determined continuously during the immersion. Mineral and microstructural changes of tested samples were analyzed to determine the attack products after 12-months immersion. Results illustrate that the development of concrete strength was limited by sulfate, chloride, magnesium, or multiple combined chemical attack at the early stage and resulted in a low strength in the long-term. Internal chlorides accelerated the degradation induced by external sulfate attack, subsequently enhancing the accumulation rate of sulfates in concrete in both sulfate and sulfate-magnesium solutions. Coexisting magnesium helps to restrain the degradation and decrease the diffusion speed of sulfates. Magnesium weakens the acceleration effect of internal chlorides on the degradation induced by sulfate attack. While the internal chlorides restrains the protection effect on internal concrete by Magnesium. Degradation layer-by-layer is the proposed mechanism when concrete subjected to magnesium involved chemical attack.

Bone, inflammation and chronic kidney disease

Increasing knowledge on inflammatory mediators and bone metabolism highlights the relationship between inflammation and bone disease. During acute illness, inflammatory cells and cytokines modulate bone cells activity so as to mobilize calcium seemingly to supply the metabolic requirements for immune response. In case of long lasting, chronic inflammatory states a condition of maladaptive, smouldering inflammation is realized and negatively affects calcium bone balance. Aging, now nicknamed inflammaging, is regarded as a chronic inflammatory condition, characterized by increased circulating inflammatory cytokines, that contributes to the development of osteoporosis, cardiovascular diseases and chronic kidney disease. In patients with renal insufficiency, the development of bone and mineral disorders (so called CKD-MBD “syndrome”) is now a recognized pathogenic factor for the seemingly accelerated process of aging and for the increased risk of cardiovascular death in these patients. The adaptive changes in mineral and bone metabolism developing in the early stages of chronic kidney disease could represent a hypothetical model of accelerated aging, osteoporosis and cardiovascular disease.

Analysis on the Changes of Functional Groups after Coal Dust Explosion at Different Concentrations Based on FTIR and XRD

ABSTRACT In this study, experiments were performed on coal dust explosion (CDE) at different concentrations by using a 20 L spherical explosion device. Besides, the raw coal and solid residues of CDE were subjected to FTIR and XRD analyses. The aims are to investigate the changes of functional groups after CDE at different concentrations, the relationship between functional group consumption rate and explosion characteristic parameters, and the changes of inorganic minerals. The results show that during the CDE, various functional groups are consumed to varying degrees. Among the groups, the consumption of oxygen-containing functional groups is the most, followed by those of hydroxyl groups and aliphatic hydrocarbons, and that of aromatic hydrocarbons is the least. When the coal dust concentration is greater than 200 g/m3, the functional group consumption rate exceeds 50%; when the coal dust concentration exceeds 500 g/m3, the functional group consumption rate exceeds 90%. The total consumption of functional groups is positively correlated with the explosion pressure P m, the growth rate of explosion pressure (dp/dt)m, the flame propagation velocity V F and the impulse I during the CDE experiments. Compared with raw coal, solid residues of CDE possess an increased content of minerals. The absorption peak area of minerals reaches a maximum of 10.28 (about 10 times of that for the raw coal) under the concentration of 700 g/m3. The main mineral components vary before and after the CDE. The main mineral components in the raw coal are quartz and kaolinite, while the main mineral components in the solid residues after CDE are quartz, calcium zeolite, wollastonite and magnesium oxide.

A calcified chronic total occlusion preclinical model.

To create an experimental chronic total occlusion (CTO) model with calcification by dietary modification (cholesterol, calcium carbonate, vitamin D) and local injection of pro-calcification factors (dipotassium phosphate, calcium chloride, and bone morphogenetic protein-2 [BMP-2]). Percutaneous revascularization of CTOs frequently fails in heavily calcified occlusions. Development of novel approaches requires a reproducible preclinical model of calcified CTO. CTOs were created in 18 femoral arteries of 9 New Zealand White rabbits using the thrombin injection model. Dietary interventions included a high cholesterol diet (0.5% or 0.25%), calcium carbonate (150 mg × 3-5 days/week), and vitamin D (50,000 U × 3-5 days/week). In selected animals, BMP-2 (1-4 μg), dipotassium phosphate, and calcium chloride were injected locally at the time of CTO creation. Animals were sacrificed at 2 weeks (n = 4 arteries), 6 weeks (n = 4 arteries), and 10-12 weeks (n = 14 arteries). CTOs showed evidence of chronic lipid feeding (foam cells) and chronic inflammation (intimal/medial fibrosis and microvessels, inflammatory cells, internal elastic lamina disruption). In calcium/vitamin D supplemented rabbits, mineralization (calcification and/or ossification) was evident as early as 2 weeks post CTO creation, and in 78% of the overall arteries. Mineralization changes were not present in the absence of calcium/vitamin D dietary supplements. Mineralization occurred in 85% of BMP-treated arteries and 60% of arteries without BMP. Complex mineralization occurs in preclinical CTO models with dietary supplementation of cholesterol with vitamin D and calcium.

Enamel Subsurface Caries-Like Lesions Induced in Human Teeth By Different Solutions: A TMR Analysis.

This study assessed the effectiveness of models for developing subsurface caries lesions in vitro and verified mineral changes by transverse microradiography (TMR). Enamel blocks from permanent (n=5) and deciduous teeth (n=5) were submitted to lesion induction by immersion in demineralizing solutions during 96 h, followed by pH cycles of demineralization (de) and remineralization (re) for 10 days. Two de-/re solutions were tested. Demineralizing solution "A" was composed by 2.2 mM CaCl2, 2.2 mM KH2PO4, 0.05 M acetic acid, with pH 4.4 adjusted by 1 M KOH. Demineralizing solution "B" was composed by 2.2 mM CaCl2, 2.2 mM NaH2PO4, 0.05 M acetic acid and 0.25 ppmF, with pH 4.5 adjusted by 1M KOH. Solution "A" produced cavitated lesions in permanent teeth, whereas solution "B" led to subsurface lesions in deciduous teeth. Solution "B" was then tested in enamel blocks from permanent teeth (n=5) and subsurface lesions were obtained, so that solution "B" was employed for both substrates, and the blocks were treated with slurries of a fluoride dentifrice (1450 ppm F, as NaF, n=5) or a fluoride-free dentifrice (n=5). Solution "B" produced subsurface lesions in permanent and primary teeth of an average (±SD) depth of 88.4µm (±14.3) and 89.3µm (±15.8), respectively. TMR analysis demonstrated that lesions treated with fluoride-free dentifrice had significantly greater mineral loss. This study concluded that solution "B" developed subsurface lesions after pH cycling, and that mineral changes were successfully assessed by TMR.

Influence of Alien Species Pistia stratiotes L., 1753 on Representative Species of Genus Salvinia in Ukraine

Abstract This work purpose was to find the impact of Pistia stratiotes L., 1753 - a new species on the territory of Ukraine, on the vitality of other free-floating hydrophytes so-called pleuston- Salvinia natans (L.) All., 1785, S. laevigatum (Humb. and Bonpl. ex Willd.) Heine, 1968, to determine the degree of stability and competitiveness of these species for resources in natural ecosystems relatively to the undesirable species. To find out the influence of P. stratiotes on other free-floating on the water surface plant species which compete for elements of nutrition among each other, we have investigated changes in the content of photosynthetic pigments in S. laevigatum and S. natans, which were exhibited with P. stratiotes for 14 days. Besides changes in water indices, oxygen content, mineralization and pH, were measured.

Mineralogical and geochemical characteristics of hydrocarbon-bleached rocks in Baiyanggou mud volcanoes, Xinjiang, NW China

A total of 11 rock samples were systematically collected along the main flow of geofluids running on the slope of the Baiyanggou mud volcanic system and analyzed for their mineralogical and chemical compositions as well as for iron species using XRD, XRF and Mössbauer spectroscopy, respectively. The analytical results clearly indicated spatial variations for most geochemical parameters caused by redox fluctuation processes around the Baiyanggou mud volcanic system. Close to the mud volcanic craters, the bleached greyish rocks mainly contained ferrous iron in chlorite and muscovite (para-Fe2+) with some portion of ferric hydroxide and ferric iron in clay minerals (para-Fe3+), suggesting a strong reducing environment. Further away from the craters, the relative contents of reducing iron species (Fe2+) in the rocks gradually decreased. The reddish rocks did not appear to be greatly influenced by erupting geofluid and contained relatively high contents of para-Fe3+ and ferric iron in hematite (hem-Fe3+). A redox front occurred at a certain distance from the active mud volcanic craters, in which sharp changes of iron-bearing minerals could be tracked. The reducing and weakly alkaline medium contributed to the precipitation of secondary carbonate minerals such as calcite and siderite. Geofluids composed of brackish waters, gases and oils tended to migrate through sandy veins in a clay sequence, faults and fracture networks with relatively high porosity and permeability. Iron speciation of the solid rocks in the seepage areas could therefore be considered a potential indicator for the migration of reducing geofluids including hydrocarbons located underground.

Experimental Investigation of Anisotropic Thermal Deformation of Oil Shale Under High Temperature and Triaxial Stress Based on Mineral and Micro-fracture Characteristics

The anisotropic deformation of oil shale at different temperatures should be given particular attention considering that thermal deformation affects borehole stability, oil and gas permeation channel formation and surface subsidence during the pyrolysis of oil shale. The deformation of oil shale parallel and perpendicular to the bedding directions under different triaxial stresses was studied from room temperature to 600 °C. Evolutions in mineral compositions and thermal fracturing were studied by X-ray diffractometry and computer tomography, respectively. The main results are as follows. (1) Under 2.5 and 5 MPa axial stresses, the thermal deformation perpendicular to the bedding direction shows compressive deformation with increasing temperature, and the strain rate increases sharply at 200 °C, 350 °C and 400 °C. When the axial stress is 10 MPa, the deformation rate increases sharply when the temperature increases to 100 °C, and then, the compression deformation increases almost linearly. (2) Under 2.5 and 5 MPa axial stresses, the thermal deformation parallel to the bedding tends to be expansion–compression–expansion–recompression with increasing temperature. When the axial stress increases to 10 MPa, the overall deformation of the material will be compression deformation, and no expansion deformation will occur with the increase in temperature. (3) The deformation characteristics under the coupled action of temperature and stress are less related to mineral changes but more related to fracture evolution characteristics. (4) Thermal stress has a great influence on the thermal deformation of oil shale perpendicular to the bedding directions but little effect on the thermal deformation parallel to the bedding directions.

Pregnancy-Related Bone Mineral and Microarchitecture Changes in Women Aged 30 to 45 Years.

ABSTRACTAt birth, the neonatal skeleton contains 20 to 30 g calcium (Ca). It is hypothesized maternal bone mineral may be mobilized to support fetal skeletal development, although evidence of pregnancy‐induced mineral mobilization is limited. We recruited healthy pregnant (n = 53) and non‐pregnant non‐lactating (NPNL; n = 37) women aged 30 to 45 years (mean age 35.4 ± 3.8 years) and obtained peripheral quantitative computed tomography (pQCT) and high‐resolution pQCT (HR‐pQCT) scans from the tibia and radius at 14 to 16 and 34 to 36 weeks of pregnancy, with a similar scan interval for NPNL. Multiple linear regression models were used to assess group differences in change between baseline and follow‐up; differences are expressed as standard deviation scores (SDS) ± SEM. Decreases in volumetric bone mineral density (vBMD) outcomes were found in both groups; however, pregnancy‐related decreases for pQCT total and trabecular vBMD were −0.65 ± 0.22 SDS and −0.50 ± 0.23 SDS greater (p < .05). HR‐pQCT total and cortical vBMD decreased compared with NPNL by −0.49 ± 0.24 SDS and −0.67 ± 0.23 SDS, respectively; trabecular vBMD decreased in both groups to a similar magnitude. Pregnancy‐related changes in bone microarchitecture significantly exceeded NPNL change for trabecular number (0.47 ± 0.23 SDS), trabecular separation (−0.54 ± 0.24 SDS), cortical thickness (−1.01 ± 0.21 SDS), and cortical perimeter (0.78 ± 0.23 SDS). At the proximal radius, cortical vBMD and endosteal circumference increased by 0.50 ± 0.23 SDS and 0.46 ± 0.23 SDS, respectively, compared with NPNL, whereas cortical thickness decreased −0.50 ± 0.22 SDS. Pregnancy‐related decreases in total and compartment‐specific vBMD exceed age‐related change at the distal tibia. Changes at the radius were only evident with pQCT at the cortical‐rich proximal site and suggest endosteal resorption. Although the magnitude of these pregnancy‐related changes in the appendicular skeleton are small, if they reflect global changes across the skeleton at large, they may contribute substantially to the Ca requirements of the fetus. © 2020 Crown copyright. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR). This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.

Carbon mineralization, biological indicators, and phytotoxicity to assess the impact of urban sewage sludge on two light-textured soils in a microcosm.

The agricultural reuse of urban sewage sludge (USS) modifies soil properties depending on sludge quality, management, and pedo-environmental conditions. The aim of this microcosm study was to assess C mineralization and subsequent changes in soil properties after USS addition to two typical Mediterranean soils: sandy (Soil S) and sandy loam (Soil A) at equivalent field rates of 40 t ha-1 (USS-40) and 120 t ha-1 (USS-120). Outcomes proved the biodegradability of USS through immediate CO2 release inside incubation bottles in a dose-dependent manner. Accordingly, the highest rates of daily C emission were recorded with USS-120 (3.7 and 3.9mg kg-1 d-1 for Soils S and A, respectively) after 84 d of incubation at 25 °C. The addition of USS also improved soil fertility by enhancing soil macronutrients, microbial proliferation, and protease activity. Protease showed significant correlation with N, total organic C, and heterotrophic bacteria, reflecting the biostimulation and bioaugmentation effects of sludge. Soil indices like C/N/P stoichiometry and metabolic quotient (qCO2 ) varied mostly with mineralization rates of C and P in both soils. Despite a significant increase of soil salinity and total heavy metal content (lead, nickel, zinc, and copper) with USS dose, wheat germination was not affected by these changes. Both experimental soils showed intrinsic (Soil A) and incubation-induced (Soil S) phytotoxicities that were alleviated by USS addition. This was likely due to the enhancement of biodegradation and/or retention of phytotoxicants originating from previous land uses. Urban sewage sludge amendments could have applications in soil remediation by reducing the negative effects of allelopathic and/or anthropogenic phytoinhibitors.

Short-Term Nitrogen Fertilization Affects Microbial Community Composition and Nitrogen Mineralization Functions in an Agricultural Soil.

Soil extracellular enzymes play a significant role in the N mineralization process. However, few studies have documented the linkage between enzyme activity and the microbial community that performs the function. This study examined the effects of inorganic and organic N fertilization on soil microbial communities and their N mineralization functions over 4 years. Soils were collected from silage corn field plots with four contrasting N treatments: control (no additional N), ammonium sulfate (AS; 100 and 200 kg of N ha-1), and compost (200 kg of N ha-1). Illumina amplicon sequencing was used to comprehensively assess the overall bacterial community (16S rRNA genes), bacterial ureolytic community (ureC), and bacterial chitinolytic community (chiA). Selected genes involved in N mineralization were also examined using quantitative real-time PCR and metagenomics. Enzymes (and marker genes) included protease (npr and sub), chitinase (chiA), urease (ureC), and arginase (rocF). Compost significantly increased diversity of overall bacterial communities even after one application, while ammonium fertilizers had no influence on the overall bacterial communities over four seasons. Bacterial ureolytic and chitinolytic communities were significantly changed by N fertilization. Compost treatment strongly elevated soil enzyme activities after 4 years of repeated application. Functional gene abundances were not significantly affected by N treatments, and they were not correlated with corresponding enzyme activities. N mineralization genes were recovered from soil metagenomes based on a gene-targeted assembly. Understanding how the structure and function of soil microbial communities involved with N mineralization change in response to fertilization practices may indicate suitable agricultural management practices that improve ecosystem services while reducing negative environmental consequences.IMPORTANCE Agricultural N management practices influence the enzymatic activities involved in N mineralization. However, specific enzyme activities do not identify the microbial species directly involved in the measured process, leaving the link between the composition of the microbial community and the production of key enzymes poorly understood. In this study, the application of high-throughput sequencing, real-time PCR, and metagenomics shed light on how the abundance and diversity of microorganisms involved in N mineralization respond to N management. We suggest that N fertilization has significantly changed bacterial ureolytic and chitinolytic communities.

The Effect of Bread Fortification with Whole Green Banana Flour on Its Physicochemical, Nutritional and In Vitro Digestibility.

The use of Whole Green Banana Flour (WGBF) in bread production may be a strategy to improve the nutritional profile of bread, but the extent of improvement may depend on the processing conditions of the flour. Therefore, WGBF was produced using two methods (freeze-drying and air-oven drying) and was used in bread-making. This study investigated the effect of flour type—FDF (WGBF produced by freeze-drying) and ODF (prepared by air-oven drying at 50 °C)—at fortification levels of 0% (control), 10%, 20%, and 30% on the fortified bread. A significant decrease in energy caloric value and an increase in moisture and fibre at >20% fortification level (p < 0.05) was noted. The ODF bread samples had a higher browning index compared to the control and the FDF samples. Addition of WGBF improved macro minerals (Mg, Ca, Na, K, and P) with a no significant change in micro minerals (Fe, Zn, and Mn). The use of FDF in bread resulted in a marked increase in resistant and slow digestible starch levels in F30 compared to ODF samples and their comparable fortification levels. The digestibility of the bread samples showed that WGBF can be used as an alternative functional ingredient to prepare bread with better nutritional value.

Characterization and recovery of rare earth elements and other critical metals (Co, Cr, Li, Mn, Sr, and V) from the calcination products of a coal refuse sample

The impacts of calcination on the leaching recovery of rare earth elements (REEs) and other critical metals from a Baker seam coal refuse material were investigated in this study. Acid leaching test results showed that leaching recovery of the REEs, especially the light REEs, was increased significantly from around 24% to 80–90% after calcination under 600–750 °C for two hours. By considering the major element leaching kinetics and the mineralogical changes of the dominant minerals caused by calcination, two mechanisms were proposed for the improved leaching performance: (1) decomposition of difficult-to-dissolve REE-bearing minerals into soluble forms; and (2) liberation of REE-bearing minerals encapsulated in clays after calcination due to the dehydration and disintegration of the layered clay structure. Sequential chemical extraction tests showed that a significant fraction (around 75%) of the REEs in the raw material were present in an insoluble form. After calcination under proper temperatures (600–800 °C), the majority of the insoluble light REEs (LREEs) were converted into soluble forms. Changes in the modes of occurrence of the LREEs and phosphorous based on leaching rate and sequential leaching correlated well as a function of the calcination temperature. This finding in addition to SEM-EDX results tends to indicate the potential that the LREEs occur primarily as rare earth phosphates such as monazite in the untreated coal refuse material. The acid leaching and sequential chemical extraction results show that co-extraction of REEs and other critical metals such as Co, Mn, and Li is possible using a calcination-acid leaching procedure.

Optimized Method of Estimating Mineral Reserves Using the O’Hara Mathematical Model for Underground Mining in Peru

This research project is aimed at applying the proposed methodology to optimize the calculation of mining reserves using an empirical relationship for dilution, as proposed by O’Hara. This methodology uses three key parameters: dilution, mineral value, and total costs. In general, costs include mining costs, processing within plants, and administrative expenses related to producing a mineralized block. Similarly, to calculate the mineral value, studies on changes in mineral prices over the last 30 years were included to provide more representative values. The research was applied to mineralized block number 1000, which yielded positive results since dilution could be easily calculated using three key parameters: operating method, dip, and vein width. The dilution value of 12.25% was valid, as it was within the range of 10% to 23%. This range was considered based on other studies that apply this operating method. Then, the methodology was analyzed in three more settings, each represented by a mineralized block. The blocks assessed were 1001, 1002, and 1003, and the results indicated that the dilution found was acceptable at values of 18%, 19%, and 22%, respectively.