Fraction Of Boron Research Articles

Boron nitride: Novel ceramic reductant for low‐activity waste vitrification

AbstractDuring vitrification of radioactive wastes, excessive foaming reduces processing rates within melters by hindering heat transfer from the molten glass pool to the reacting melter feed. Formulations of low‐activity waste (LAW) melter feeds, for vitrification at the Waste Treatment and Immobilization Plant at the Hanford Site, conventionally include the addition of sucrose to mitigate excessive foaming by hastening the denitration process. However, incomplete combustion of sucrose produces organics such as acetonitrile (C2H3N) that may exceed bounding limits of downstream effluent treatment facilities. Using boron nitride (BN) as an alternate reductant to sucrose, in a representative LAW melter feed reduced C2H3N production by 90% by preventing the low‐temperature sucrose–nitrate reactions. Furthermore, foaming was suppressed due to the higher decomposition temperature of BN than H3BO3 meaning a delayed reaction of a large fraction of boron with the transient glass‐forming melt until above the foam onset temperature, thus reducing the quantity and viscosity of the connected melt and trapping less gas in the foam layer.

Deuterium plasma induced preferential erosion in ultra-high temperature ceramics TiB2 and ZrB2*

Abstract Steady-state deuterium plasma exposures were performed on ultra-high temperature ceramics titanium diboride (TiB2) and zirconium diboride (ZrB2) using the PISCES-RF linear plasma device (LPD) as early screening for first wall, plasma-facing applications. Deuterium plasma exposures were performed using 40 eV ion energies at 240, 525, and 800 °C sample temperatures and 90 eV ion energies at 240 °C sample temperatures to analyze TiB2 and ZrB2 surface morphology and chemistry evolution behavior. Post-plasma exposure chemistry characterization of the near surface ( < 50 nm) region of the samples all show transition metal enrichment, indicating boron preferential erosion. Transition metal to boron fractions vary with plasma exposure temperature under the 40 eV ion energy; metal enrichment is maximized at 800 °C and then minimized at 525 °C. SEM micrographs of all plasma exposed sample surfaces show no significant or noticeable plasma induced damage from cracking or blistering.

Adsorption pathways of boron on clay and their implications for boron cycling on land and in the ocean

Reversible adsorption and isotope fractionation of boron on the surface of clay minerals is a key process that impacts boron isotope cycling in porewater, rivers and the ocean. However, the differences in boron isotope fractionation factors between various clay minerals and their dependence on fluid chemistry are not well known. We performed two sets of experiments, using solutions of pure water with added boron and seawater, to explore the isotope behavior during adsorption of boron onto kaolinite, smectite and illite. We found that the amount of sorbed boron increases with ionic strength of solutions and is proportional to the cation exchange capacity of a given clay mineral. Maximum adsorption is observed in alkaline seawater, which we attribute to the efficient fixation of magnesium-borate ion pairs onto negatively charged surface sites. Isotopic fractionation is modestly different between clays and demonstrates that clay surfaces preferentially sorb borate, even when the concentration of borate in solution is low. In both pure water and seawater, adsorbed complexes retain the isotopic composition of their dissolved precursors (borate or boric acid) with minimal isotopic fractionation. In other words, isotopic composition of adsorbed boron is set by the ability of clays to adsorb boron from an already fractionated boron pool rather than specific fractionation associated with the complexation reaction. Our experimental results allow us to provide revised constraints on the adsorbed boron being transported in terrestrial fluids and the ocean.

Influence of Selenium Oxide on Structure and Properties of New Zinc Boroselenite Glasses

The traditional melt quenching method was used to prepare new zinc boroselenite glasses in the system xSeO2·(50 − x)ZnO·50B2O3 with varying SeO2/ZnO molar ratio. X-ray diffraction patterns (XRD) have revealed an amorphous structure in glasses of up to 40 mol pct SeO2. On the other hand, the presence of sharp diffraction peaks on the XRD spectra of samples containing 40 and 50 mol pct SeO2 confirms a formation of some polycrystalline phases distributed in the host glass network. Based on FTIR and NMR data, the glass structure at a short-range order exhibited a similar value of the fraction of tetrahedral boron (N4), particularly, for both samples of 0 and 5 mol pct SeO2. In this situation, SeO2 is as well as ZnO both played a modifier role. On the other hand, increasing SeO2 on expense of ZnO decreases the N4 fraction gradually. However, in SeO2-rich glass, most of boron atoms are mainly placed in three coordinated sites in BO3 units coordinated with SeO4 groups. Decreasing N4 fraction and increasing crystallization confirmed that SeO2 operates as a glass former and mainly as a crystalline agent. The results based on the TEM of the selected area of electron diffraction patterns (EDP) agree well with the ones obtained by XRD. The diffraction patterns clearly displayed two sets of diffraction rings: one is caused by boroselenite nanocrystals and the other by zinc selenite. In contrast, a broader halo of dispersed structure, known as an amorphous structure, is present in the diffraction pattern obtained from SeO2-free glass.

Thermoviscosimetric characteristics of borosilicate glasses with regard to the promising area of low-melting compositions currently being developed for the removable small-scale melter designed by Mayak Production Association

Relevance. The need to obtain experimental data on dependence of thermoviscosimetric properties of the examined borosilicate glasses on temperature, in order to solve the problem of developing a low-melting composition of borosilicate glass for a small-scale melter designed by Mayak Production Association. Aim. To get the most complete characterization of the glasses under study using thermoviscometric measurements. Methods. Mathematical modelling, simplex-lattice design. Results and conclusions. One of the most effective methods of experiment planning, which allows, with a relatively small number of experiments, obtaining a mathematical model reflecting the dependence of the studied property of the mixture on the content of components in it, is the simplex experiment planning method. To simplify the solution of such a task, a group or groups of components are usually distinguished, in which the ratio of the mass fraction of the components does not change. In this article, three groups of components are taken – simulators of high-level radioactive waste, sodium and boron oxides, and glass frit. The authors have identified the most promising area, where the mass fraction of glass frit is from 67.5 to 75%, the mass fraction of sodium and boron is from 25 to 32.5% and the mass fraction of high-level waste components is from 0 to 20%. The paper presents the results of thermoviscometric measurements of 15 melts of low-melting borosilicate glasses of different compositions at temperatures ranging from 700 to 1,200°C. Using simplex-based mathematical models of experiment planning, domains of dependence of thermoviscosimetric characteristics of glass melts on their compositions were created. The authors identified the compositions of glass melts that are found within the viscosity limits determined as allowable for glass melt discharge during operation of the removable small-scale melter of Mayak Production Association design.

Ecological implications of boron and sulfur in sediments from a lake in the Nile Delta: Remote sensing, fractionation and ecotoxicity

PurposeThe study aimed to provide an overview of the behavior, fate and ecotoxicity of boron and sulfur in the sediments of Lake Burullus, Egypt, after the degradation of the lake area.Materials and methodsChanges in the studied lake area due to human activities were estimated using Erdas Imagine v14 and ArcGIS. Sequential and non-sequential extraction techniques for boron and sulfur fractionation in sediments were evaluated.Results and discussionA remote-sensing tracking investigation revealed a decrease in area of about 19.4%. Boron geochemical fractions had the order of residual (BF5, 61.48 ± 3.84%) > bound oxide (BF3, 15.47 ± 9.64%) > specifically adsorbed (BF2, 13.34 ± 9.85%) > bound organic (BF4, 9.85 ± 12.40%) > water-soluble and exchangeable (BF1, 2.2 ± 2.66%). Sulfur gave the order of the fractions as residual (SF5, 70.52 ± 16.92%) > phosphate extractable (SF2, 15.47 ± 9.34%) > bound organic (SF4, 7.20 ± 5.35%) > CaCl2 -extractable (SF3, 9.85 ± 12.40%) > water-soluble sulfur (SF1, 1.34 ± 1.52%). A worst-case scenario involving boron and sulfur toxicity values was studied using mixture risk characterization ratios (RCRmix) based on the predicted no effect concentration (PNEC) and sum of toxic units (STU).ConclusionsThe RCRmix and STU of boron showed high long-term risks to aquatic organisms, while sulfur showed high short-term risks. Invertebrates were the most sensitive species to boron and sulfur. This study sheds light on the ecological impact of boron and sulfur in Lake Burullus sediments, highlighting potential risks to aquatic organisms. Further research could focus on developing mitigation strategies to address these concerns.Graphical

Determination of boron isotopic compositions in five fractions of soil boron: traces of the environmental behavior of boron in soil

A stepwise extraction method established for boron isotope measurement of five fractions in soil boron showed their feathered isotopic signals.

Influence of Selected Soil Properties and Cropping System on Soil Boron Fractions in an Inceptisol of Assam, India

The current research aimed to investigate different boron fractions in diverse cropping systems and assess their relationship with various soil physico-chemical properties. Twenty-four geo-referenced surface soil samples (0-15 cm) were collected from four cropping systems: Rice-Rice, Rice-Fallow, Vegetable-Vegetable, and Plantation crops. The study found that the available boron (ranging from 0.56 to 1.69 mg kg-1) and five boron fractions, including Readily Soluble Boron (0.04-2.41 mg kg-1), Specifically Adsorbed Boron (0.15-1.92 mg kg-1), Oxide Bound Boron (5.18-17.41 mg kg-1), Organically Bound Boron (6.86-20.3 mg kg-1), and Residual Boron (17.73-36.57 mg kg-1), did not significantly differ among the cropping systems. The results revealed that the proportions of these boron fractions in soils followed this order: Readily Soluble B < Specifically Adsorbed B < Oxide Bound B < Organically Bound B < Residual B. Additionally, pH and CEC (Cation Exchange Capacity) did not exert a significant influence on soil boron fractions, while Soil Organic Carbon (SOC) significantly impacted Oxide Bound and Organically Bound Boron fractions. Despite the different cropping systems, there were no significant variations in the various boron fractions. Furthermore, the study identified positive correlations between soil organic carbon and Oxide Bound B, Organically Bound B, Specifically Adsorbed B, and Electrical Conductivity (E.C.). The cropping system did not have a significant effect on the diverse boron fractions investigated in this study.

Repercussions of fertilization with boron and enriched organic manure on soil chemical characteristics, boron and phosphorus fractions, and French bean productivity in an acidic Inceptisol of eastern Himalaya

Boron (B) and phosphorus (P) in the soil are dispersed in numerous geochemical fractions (forms) which depend primarily on physicochemical properties of soils, climate and management exercises, and each form is in dynamic equilibrium with each other. The study of these fractions caters for an advanced understanding of their bioavailability to plants. To better elucidate how the nexus of B and enriched farmyard manure (EFYM) synergy influences the soil chemical characteristics, B and P fractions, and French bean pod production, an investigation was undertaken during the three consecutive years from 2015 to 18 in acidic Inceptisol of eastern Himalaya. The experiment was laid out in symmetrical factorial design and the imposed treatments comprised four graded levels each of B (0, 0.5, 1 and 1.5 kg ha−1) and EFYM (0, 5, 10, 15 Mg ha−1). The results implied that the conjoint (interaction) application of a higher rate of B @ 1.5 kg ha−1 and EFYM @ 15 Mg ha−1 (B1.5EFYM15) levels were superior to other treatment combinations in improving soil chemical characteristics including pH, electrical conductivity (EC), soil organic carbon content (SOC) and reducing the concentration of iron oxides (Fe2O3) and aluminium oxides (Al2O3). Similarly, there was a significant increase of B fractions, total B, Hot water-soluble B (HWS-B), P fractions, total P and available P in the soil. Correspondingly, the maximum average French bean pod yield (FBPY) (12.04 Mg ha−1) was achieved under plots fertilized with B1.5EFYM15, while the minimum FBPY (7.82 Mg ha−1) was logged under B0EFYM0 (control). The correlation study exhibited a significant positive correlation amongst EC, SOC and cation exchange capacity (CEC) with both the B and P fractions. Of the various B fractions, readily soluble B (RSB) followed by organic bound B (OBB) was the most overriding B fraction affecting the available B. Likewise, concerning the P fraction, Resin P followed by bicarbonate extracted inorganic and organic P fractions (BiCPi and BiCPo), was realized to be the overriding P fraction implicated in affecting the available P. Higher phosphorus activation coefficient (PAC) was logged in those plots fertilized with B1.5EFYM15. The inclusive findings indicated that the addition of the successive increase in the level of B and EFYM up to B1.5EFYM15 can enhance the status of soil characteristics, diverse B fractions, total B, Hot water-soluble B (HWS-B), P fractions, Total P and available P and ultimately the FBPY in an acidic Inceptisol of eastern Himalaya.

Soil Properties Influence Vertical Distribution of Boron Fractions in Lateritic Soil

The present study was conducted at Palli Siksha Bhavana (Institute of Agriculture), Visva-Bharati, West Bengal, India, during 2019-20 to evaluate the different fractions of boron (B) along depth and their relationship to some soil properties in lateritic soils of West Bengal, India. The sequential B fractionation scheme was followed to estimate B fractions in the studied soils. It was found that most of the soils fall under the sandy clay loam and clay loam soil textural categories. The soil pH was either categorized as extremely acidic or slightly acidic in nature and the range of low to medium organic carbon content was present. The studied soils’ CEC varied between 5.90 to 26.64 [C mol (P+) kg-1]. In the B fractionation study, it was revealed that, for uptake of plants, the readily soluble boron (Rs-B) is the most easily accessible fraction among all other fractions, and the residual boron (Res-B) fraction accounts for the major portion of total soil boron (Tot-B). Different soil properties of the study area greatly influenced the B fractions along soil depths. The contribution of different B fractions towards total soil B (Tot-B) B followed the order: residual boron (Res-B) >> oxide-bound boron (Oxd-B) > organically bound boron (Org-B) > specifically adsorbed boron (Sad-B) > readily soluble boron (Rs-B). The current study will be helpful for adopting the fertilizer management practices of boron-deficient lateritic soils (Alfisols).

Boron coordination change in barium borate melts and glasses and its contribution to configurational heat capacity, entropy, and fragility.

High-energy x-ray diffraction from molten and glassy BaB2O4 and BaB4O7 has been performed using aerodynamic levitation and laser heating over a wide range of temperatures. Remarkably, even in the presence of a heavy metal modifier dominating x-ray scattering, it was possible to extract accurate values for the tetrahedral, sp3, boron fraction, N4, which declines with increasing temperature, using bond valence-based mapping from the measured mean B-O bond lengths while accounting for vibrational thermal expansion. These are used within a boron-coordination-change model to extract enthalpies, ΔH, and entropies, ΔS, of isomerization between sp2 and sp3 boron. The results for BaB4O7, ΔH = 22(3) kJ mol-1 boron, ΔS = 19(2) J mol-1 boron K-1, agree quantitatively with those found previously for Na2B4O7. Analytical expressions for N4(J, T) and associated configurational heat capacity, CPconf(J, T), and entropy, Sconf(J, T), contributions are extended to cover a wide composition range 0 ≤ J = BaO/B2O3 ≤ 3 using a model for ΔH(J) and ΔS(J) derived empirically for lithium borates. Maxima in the CPconf(J, Tg) and fragility index contributions are thereby predicted for J ≲ 1, higher than the maximum observed and predicted in N4(J, Tg) at J ≃ 0.6. We discuss the utility of the boron-coordination-change isomerization model in the context of borate liquids containing other modifiers and the prospect of neutron diffraction to aid in empirical determinations of modifier-dependent effects, illustrated by new neutron diffraction data on Ba11B4O7 glass, its well-known α-polymorph, and lesser-known δ-phase.

The Boron Budget in Waters of the Mono Basin, California

Mono Lake in eastern California has the highest natural boron concentrations measured in a natural water body. Inputs to Mono Lake are from creeks that drain from the Sierra Nevada, accounting for over 80% of the total water input, and springs account for most of the rest of the water budget. We measured boron concentrations and isotope compositions of water sources in the lake and lake water collected over several seasons. The δ11B offset of at least +2.5‰ between Mono Lake water compared to its inputs suggests that, like seawater, the boron isotopic composition of the lake is influenced by the removal of light boron by coprecipitation and/or sorption of borate. Given the alkalinity of the lake, boron fractionation likely occurs before or as the water sources enter the lake. The famous tufa towers around the lake are a physical representation of a ‘chemical delta’ that alters the boron isotopic composition of the source fluids as they enter the lake. Based on different combinations of the measured end members, the residence time of boron in Mono Lake is estimated to be within the range of 5~80 ka.

Field strength effect on elastoplastic behavior of aluminoborosilicate glass: I. Elastic moduli and indentation size effect

AbstractThe modifier field strength (FS) is believed to play an important role in determining the elastic–plastic responses of aluminoborosilicate (ABS) glasses, but its effect is not well understood. Three novel alkali and three alkaline earth (AE) ABS compositions were created for this study which is the first part of two studies that explored the elastoplastic responses of these glasses. Six compositions were designed using different network modifiers (NWMs) to cover a range of cation FS. The glasses were also designed such that the concentrations of NWM and Al2O3 were similar, which maximized the three‐coordinated boron fraction in the network. It is well known that modifier FS can affect the coordination number (CN) of Al and B in an ABS glass structure, for example, a higher FS modifier can promote B3 → B4 and higher [Al5,6], but the degree of this depends on network former (NWF) ratios. Previous work used solid‐state NMR spectroscopic analysis on the current glasses to find that there was variation between [B4] and [Al4] between the two glass series (alkali vs. AE) but that was attributed to synthesis factors and no trend with FS was associated with the varying NWF CN. Further, 29Si ssNMR showed no evidence of NBOs which made sense based on composition. The conclusion, therefore, was that there was a far greater correlation with modifier FS for the increased mechanical and physical properties rather than the CN of Al and B. Part I of the current work focused on the elastic moduli, Poisson's ratio, the indentation size effect (ISE), and the bow‐in parameter. This part laid out the foundation to investigate the intersection of these elastoplastic properties with hardness and crack resistance as a function of NWM FS. Results showed that: (i) the Young's, bulk, and shear moduli increased with modifier FS, whereas Poisson's ratio did not trend with FS; (ii) the alkali glasses had a significantly higher magnitudes of ISE compared to the AE glasses; and (iii) the bow‐in parameter was load dependent and decreased with modifier FS at the highest indentation load.

Wall conditioning effects and boron migration during boron powder injection in ASDEX Upgrade

The efficacy of boron powder injection as a wall conditioning tool method in terms of its ability to create a sufficiently uniform boron layer on plasma-facing surfaces has been studied in ASDEX Upgrade. Boron powder was injected in two series of dedicated plasma discharges at varied injection rates and total amount injected. The resulting boron deposition was determined quantitatively by exposure of witness samples followed by ex-situ surface analysis of the retrieved samples. In both experiments, isotopically enriched boron was used to distinguish the deposition of the newly injected material from the residual boron fraction in the machine originating from previous glow discharge boronisations. It could be confirmed that the injected boron is migrating and re-deposited across plasma-facing wall surfaces already within one discharge. At erosion dominated divertor areas, the boron influx from the main chamber results in formation of a mixed tungsten-boron surface layer with a boron area density of O(1nm) whereas at deposition dominated areas closed boron layers grow with ongoing boron injection to a thickness of up to O(1μm). Extrapolating the radial boron deposition profile on the samples exposed in the main chamber to the limiter front yields a similar boron coverage of O(1μm), which is about ten times higher than typical values for glow discharge boronisation. Together with the observed reduction of oxygen level and improved wall pumping, the surface analysis results demonstrate that boron powder injection provides a suitable means to refresh the wall conditioning effect of a preceding glow discharge boronisation.

The choice of methods for lithium and boron determination in lithium-boron alloys

A lithium-boron alloy (LBA) with a high lithium content (up to 70%) is used as an anode material for molten salt batteries in chemical sources of current. We present a complex of developed techniques for determining mass fractions of free lithium, total lithium, and total boron in lithium-boron alloys containing lithium mass fractions no more than 70%, boron mass fractions — no less than 26%. Optimal conditions for preparation of LBA samples and subsequent free lithium extraction from them are determined. The developed techniques are intended for i) extraction-titrimetric determination of free lithium in a content range of 20 - 50% (the relative total error no more than 1.1%); ii) determination of the total lithium content using flame atomic emission spectrometry in a content range of 59.0 - 96.0% (the relative overall error no more than 2.7%; iii) determination of the total boron content by two methods, i.e., potentiometric titration within a content range of 5 - 40% (the relative total error no more than 1.3%) and flame atomic absorption spectrometry within a content range of 4.9-50.7% (the relative total error no more than 4.9%). The results of analysis of full-scale LBA samples for the content of free lithium, total lithium and total boron are presented. It is shown that the application of two techniques for the determination of total boron content in lithium-boron alloys makes it possible to get the convergent results within the limits of measurement errors. The developed techniques are certified by the metrological service of the enterprise and can be used for the incoming and process control of the LBA production.

Long-Term Impact of Boron Addition at Various Dosages to a Groundnut-Cabbage System on Crop Yield and Boron Dynamics in Typic Haplustepts

The addition of boron (B) fertilizers to soils with low B content is required for augmenting crop yield. Therefore, it is imperative to have knowledge about the impact of long-term B addition at various dosages on crop yield and soil-B dynamics. A field experiment of a 6-year duration was carried out at Anand Agricultural University, Gujarat, India to study the influence of long-term B fertilization in the groundnut (Arachis hypogaea L.)-cabbage (Brassica oleracea var. capitata) cropping system in different rates and frequencies on yield of crops and soil-B dynamics. The direct effect of B addition on groundnut yield and the residual effect on succeeding cabbage crop yield was eval-uated. The treatments of the experiment encompassed various combinations of three frequencies and four rates of B application including one control (no B application). The application of B at different rates and frequencies significantly increased groundnut and cabbage yield in comparison to yield attained under the control. The addition of 1.0 kg B ha−1 in alternate years was found op-timum for enhancing the yield of groundnut and cabbage crops grown on study soil. Boron appli-cation enhanced B content in groundnut pod, haulm, cabbage and available B in soil. Optimal available B content in soil was 1.25 mg kg−1 for both groundnut pod and cabbage-head yield. The application of B with different rates and frequencies significantly enhanced B fractions in soil. The content of different fractions improved with the increase in rates of B application. The percentage contribution of various B fractions towards total B content followed the order: readily soluble B (0.43 to 0.55%) < specifically adsorbed B (0.74 to 0.98%) < organically bound B (0.70 to 1.55%) < ox-ide bound B (1.26 to 3.11%) < residual boron B (93 to 96.8%). Path analysis revealed the highest contribution of total boron towards groundnut-pod yield with a coefficient value of 4.30. Whereas oxide-bound boron fraction contributed to the maximum extent with a coefficient value of 0.91 towards cabbage-head yield. This information will be useful for B management in the ground-nut-cabbage cropping system grown on studied soil.

Boron fractions and its availability in soils of the Indo-Gangetic plains

We studied relationships between available B and different fractions of B in soils, and how soil properties, climatic parameters, and cropping systems influenced their contents in soils of the Indo-Gangetic Plains (IGP). Available B in soils was assessed by four methods viz., hot-calcium chloride (HCC), mannitol-calcium chloride (MCC), hydrochloric acid (HCl) and salicylic acid (SA). Soil B was also separated into five fractions viz., readily soluble B (RSB), specifically adsorbed B (SAB), organically bound B (OrB), oxides bound B (OxB) and residual B (RB). On average, a higher amount of available B was found in soils of the upper and trans region of IGP dominated by illitic minerals compared with a lower amount in the lower region dominated by kaolinitic one. Among the fractions, RB constituted ∼ 89 % of the total, followed by OxB(6.11 %) > OrgB (5.32 %) ≫ SAB (0.46 %) > RSB (0.26 %). Variations in the amount of available B, and its fractions in soils were explained on the basis of variations in soil properties and climatic parameters. For example, most of the fractions of B (SAB, OrgB and OxB) along with its available amount decreased with increasing soil depth due to declining contents of organic C and amorphous Fe- and Al-oxides. Soil properties explained 51–76 % variability in available B, and 27–65 % in different B fractions. Rice-based cropping systems mobilized RB to available (RSB and SAB) and potentially available (OxB and OrgB) fractions. Among the methods used, HCC and MCC were found suitable for assessing available B status in the soils. The study thus explained variations in B availability in rice and non-rice-based cropping systems, predicted its availability, and also identified suitable method(s) for its estimation in soils of the IGP for a better B management.

Investigation of the influence of SrO addition on the bioactivity of CaO[sbnd]Na2O-P2O5-B2O3 glass system

In this work, the role of strontium oxide in the bioactive glasses calcium-sodium-borate was studied to evaluate the bioactivity of the system and the rate of the ion release in Simulated Body Fluid (SBF). Five samples were prepared, with concentration of strontium oxide (SrO) from 0 to 20 wt%, in order to understand how SrO change the glass structure and the ionic leaching process in SBF. Results of density and molar volume, XRD, FTIR, weight loss, pH and cytotoxicity assay were presented and discussed as a function of SrO. The measured pH values of SBF, presented lower values for samples with greater amounts of SrO, suggesting that the increase of SrO in the glasses can reduce the release of the ions in SBF. The fraction of tetracoordinate boron, N4, calculated by FTIR results, increases with the addition of SrO, which shows an increase in the glass connectivity and a decrease of the chemical reactivity. The FTIR spectra and X-ray diffraction results, after immersion in SBF, confirmed the materials bioactivity with the formation of carbonated hydroxyapatite or crystalline calcium phosphate. The samples did not show in vitro cytotoxicity against osteoblast cell line. Also, we highlight that 10SrO sample has induced proliferation of osteoblast-like cells in vitro to all concentrations of glass. These results show that SrO doped calcium-sodium-borate glasses are materials with high rate of bioactivity, low cytotoxicity and reduced dissolution rate of the glasses in an aqueous medium, besides induce cells proliferation and bone tissue growth and their biocompatibility with living tissues.

Fermentation profile, aerobic stability, chemical and mineral composition of silages of mango combined with cocoa pod husk meal

The objective was to evaluate the fermentation profile, aerobic stability, chemical composition, and mineral content of silages of mango combined with cocoa pod husk meal. A completely randomized design was adopted, including four levels (65, 70, 75, and 80%) and five repetitions, totaling 20 experimental silos that were opened after 90 days of sealing. Increasing mango levels in the silages increased the dry matter recovery, total carbohydrates, and fraction B2 of carbohydrates, and reduced gas losses, dry matter, and mineral matter. The quadratic effect was found for pH, buffering capacity, potassium, boron, iron, and nitrogen fractions A and B1 + B2. Using unconventional products such as mango combined with cocoa pod husk meal for silage making can reduce the cost of food supplementation for ruminants, and the environmental contamination.

Liquid fragility maximum in lithium borate glass‐forming melts related to the local structure

AbstractThe structure of liquid lithium pyroborate, Li4B2O5 (J = Li/B = 2), has been measured over a wide temperature range by high‐energy X‐ray diffraction, and compared to that of its glass and borate liquids of other compositions. The results indicate a gradual increase in tetrahedral boron fraction from 3(1)% to 6(1)% during cooling from T = 1271(15) to 721(8) K, consistent with the larger N4 = 10(1)% found for the glass, and literature 11B nuclear magnetic resonance measurements. van't Hoff analysis based on a simple boron isomerization reaction BØ3O2– ⇌ BØO22– yields ΔH = 13(1) kJ mol–1 and ΔS = 40(1) J mol–1 K–1 for the boron coordination change from 4 to 3, which are, respectively, smaller and larger than found for singly charged isomers for J ≤ 1. With these, we extend our model for N4(J, T), nonbridging oxygen fraction fnbr(J, T), configurational heat capacity , and entropy Sconf(J, T) contributions up to J = 3. A maximum is revealed in at J = 1, and shown semi‐quantitatively to lead to a corresponding maximum in fragility contribution, akin to that observed in the total fragilities by temperature‐modulated differential scanning calorimetry. Lithium is bound to 4.6(2) oxygen in the pyroborate liquid, with 2.7(1) bonds centered around 1.946(8) Å and 1.9(1) around 2.42(1) Å. In the glass, nLiO = 5.4(4), the increase being due to an increase in the number of short Li–O bonds.