Solubility Of Mn Research Articles

Identification and Diversity of Mycorrhizae in Several Rhizospheres of Plant Vegetation in Ultisol Land

The poor fertility of ultisol soil hinders the cultivation of food, horticultural crops, and plantation crop nurseries, leading to the abandonment of many lands. Low fertility and productivity levels and high solubility of Al, Mn, and Fe characterize ultisol soil. One effective method to enhance soil properties is by utilizing arbuscular mycorrhiza. Arbuscular Mycorrhizal Fungi (AMF) play a crucial role in improving nutrient and water absorption, thereby enhancing the growth potential of AMF-infected roots and plants. This study aims to identify the types and diversity of mycorrhizae present in the rhizosphere of plants growing in Ultisol soil. The study employed an exploratory approach involving the collection of soil and plant samples, analysing soil, and identifying Arbuscular Mycorrhizal Fungi (AMF) in Ultisol vegetation. The results revealed the presence of AMF in the rhizospheres of various plant species, including Seduduk, Harendong, Kirinyuh, Alang-Alang, and Paku Resam. Three mycorrhizal genera were identified, namely Glomus, Acaulospora, and Gigaspora.

Enhancement of the thermoelectric performance of SnTe via Mn solubility control

Thermoelectric materials have drawn attention due to their capability of directly converting heat and electricity, which helps utilize waste heat and provides an alternative energy source.

Recovery of NMC-lithium battery black mass by microwave heating processes

The exceptional microwave absorption capabilities of carbon-based materials make them highly effective for facilitating various chemical reactions, such as synthesis, reduction, exfoliation, doping, and decoration. In this study, we applied microwave irradiation to the thermochemical treatment of spent nickel manganese cobalt (NMC622) lithium-ion batteries, obtained as a mix of the cathode and the anodic graphite. This approach significantly accelerated the chemical reactions, leveraging carbon's robust ability to absorb microwave energy. As a proof-of-concept, we demonstrated that within just 5 min, the carbothermic reduction reactions in the black mass facilitated the formation of water-soluble Li2O, and enhanced the solubility of Co, Mn, and Ni in a weak acid. More than 90% of Li and 87% of Mn are recovered. This method, which bypasses the need for cathodic and anodic separation, presents a promising new approach for recovering strategic metals from spent lithium-ion batteries.

Trace Mineral Source Influences Trace Mineral Solubility in Water and Mineral Binding Strength to Ruminal Digesta.

Two experiments were conducted to examine the impact of trace mineral (TM) source on in vitro and in vivo solubility characteristics. Experiment 1: Hydroxy TM (HTM) and sulfate TM (STM) sources of Cu, Mn, and Zn were incubated separately in water for 24 h. Immediately after mixing, initial pH of each solution was greater (P < 0.03) for HTM compared to STM for all elements. Final pH tended to be greater for Cu (P = 0.09) and Zn (P = 0.07) from HTM compared to STM. Water solubility of Cu, Mn, and Zn from STM was greater (P < 0.01) than HTM sources. Experiment 2: Eight steers fitted with rumen cannula were blocked by body weight and randomly assigned to treatments. Treatments consisted of 10 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either STM or HTM sources. Steers were individually fed a cracked corn-corn silage-based diet. Treatments were top-dressed daily. Rumen contents were collected at 0, 2, and 4 h post-feeding on d 1 and 14. On d 15, strained ruminal fluid and particle-associated microorganisms were obtained. Zinc was more tightly bound (P = 0.01) to the digesta in HTM-supplemented steers compared to STM on d 14. These data indicate that TM source influences pH and solubility of Cu, Mn, and Zn in water and may affect rumen soluble Cu concentrations and binding strength of Zn to solid digesta.

The Dominant Effect of Electrolyte Concentration on Rechargeability of γ-MnO2 Cathodes in Alkaline Batteries

Achieving high cycle life rechargeable γ-MnO2 cathodes in alkaline batteries face many challenges. Chief among these is the inability of the γ-MnO2 polymorph to retain its structural integrity when cycled to high utilization of its theoretical capacity ∼300 mAh g−1. In this paper, we investigate the root cause of failure of MnO2 cathodes under deep cycling in the one-electron discharge range and establish a strong link between capacity fade and the amount of birnessite formed. We uncover the underlying cause of failure by cycling industrial scale γ-MnO2 cathodes at various levels of theoretical capacity utilization (100%, 50%, and 30%) and in different KOH concentrations (37, 25, and 10 wt%). To determine materials evolution the cycled cathodes were dissected, characterized and analyzed using SEM, XRD, FIB/SEM, EIS, and XPS. Based on our findings, we propose that one major cause of failure of MnO2 cathodes stems from the solubility of Mn+3 formed during discharge which effectively results in destruction of the γ-MnO2 phase and amorphization of the cathode. The results show that the bulk of the γ-MnO2 phase is preserved only in ∼10 wt% KOH, which indicates the attractive range of KOH concentration for cycling of rechargeable γ-MnO2 cathodes.

Investigation of a haze-to-dust and dust swing process at a coastal city in northern China part II: A study on the solubility of iron and manganese across aerosol sources and secondary processes

The soluble fractions of iron (FeS) and manganese (MnS) in atmospheric aerosols potentially impact human health and ocean ecosystems. This study investigated a persistent haze-to-dust process observed in winter Qingdao, a coastal city in Northern China, focusing on the aerosol sources and acidification process affecting the dissolution of Fe and Mn. It was found that FeS in PM2.5 peaked during the intermingling of dust plumes with local haze, while other species of Fe and Mn reached their maximal levels coinciding with PM10. Positive Matrix Factorization (PMF) analysis determined that aged dust was the main source of FeS in PM2.5, accounting for 44.0%, while fresh dust contributed just 1.9%. Conversely, fresh dust played a more significant role in PM10, contributing 8.9% to FeS. Similar trends were observed in the initial dust and dust swing periods, aged dust was the dominant contributor to FeS, but fresh dust accounted for a higher fraction in PM10 (11.5%) than in PM2.5 (4.9%). In contrast, MnS levels, with high solubility (%MnS), were mainly from fresh dust (27.9% and 63.2% in PM2.5 and PM10, respectively). The PMF estimated %MnS in fresh dust at 17.0% for PM2.5 and 19.4% for PM10, considerably higher than Fe solubility (%FeS) at 0.3% and 0.1% in the corresponding particulate sizes. Additionally, %FeS correlated more strongly with sulfate and nitrate per unit Fe mass (R2 = 0.68 and 0.79 in PM2.5 and PM10) than %MnS (R2 = 0.49 and 0.50), suggesting a more profound impact of acidification on Fe dissolution. Further analysis suggests liquid water content rather than pH played a more critical role during the acidification process within fine particles. This study successfully estimated the solubility of Fe and Mn within various aerosols, providing valuable information and advancing our understanding of their dissolution and potential health and ecosystem impacts.

Robust Room Temperature Thermoelectric Performance of Mg3(Sb, Bi)2‐Based Alloys via Multivalent Mn Doping

Abstractn‐type Mg3(Sb, Bi)2 has excellent room temperature thermoelectric performance, which is, however, severely restricted by the negatively charged Mg vacancies that significantly deteriorate the carrier mobility. Herein, by manipulating the threshold solubility and defect formation energy of Mn, multivalent Mn is selectively introduced that synergistically promotes the carrier conduction according to different Mg chemical potentials; In Mg‐rich areas, interstitial Mn dominates which effectively reduces the migration and accumulation of Mg vacancies, while in Mg poor areas, interstitial Mn switches to substitutional sites that directly compensate for the negative charge. All the Mn centers possess Jahn–Teller inactive positions, leading to an ultra‐stable room temperature thermoelectric performance with a leading ZT up to 0.97. This work reveals the critical effect of multivalent and multifunctional transition metal incorporation in Mg3(Sb, Bi)2‐based alloys toward high room‐temperature thermoelectric performance.

Effects of quenching temperature on the structure, segregation, and properties of the AM4.5Kd + 0.2 wt.% La alloy after artificial aging

The identification of structural components in the AM4.5Kd + 0.2 wt.% La alloy, subjected to quenching at different temperatures (535–605 °C) and artificial aging at 155 °C for 4 h, was conducted through electron microscopy and XRD. An increase in the quenching temperature from 535 to 605 °C promotes the enlargement of structural components, including the α-solid solution, various aluminides, and eutectics. We observed that the base metal is not homogeneous in its chemical composition, consisting of two types of solid solutions: α1 and α2. The Cu and Mn solubility in the α2-solid solution is higher than in the α1-solid solution. As the quenching temperature increases to tq = 605 °C, the copper content in the α1-solid solution decreases. In contrast, the copper content in the α2-solid solution follows a curve with two maxima at 545 °С (4.5 at.%) and 585 °С (8.7 at.%). The Mn content in the α1-solid solution decreases sharply to the 545 °С quenching temperature and remains relatively constant up to tq = 605 °С (0.2 at.%). The Mn content in the α2-solid solution follows a curve with its maximum at tq = 545 °С (4.3 at.% Mn). Subsequent temperature rise results in a sharp drop in Mn content from 1.0 at.% at t = 565 °С to 0.3 at.% at 605 °С. Hence, the max solubility of Cu and Mn in the α2-solid solution occurs at 545 °C. At 585 °С, only an elevated Cu content (~8.7 at.%) was observed. Aluminides of alloying elements with different stoichiometries crystallize at different quenching temperatures, with complex AlxTiyLazCuvCdw and AlxCuyMnzCdv alloyed aluminides being most commonly found. ncreasing the quenching temperature to 535–545 °С results in higher hardness of the AM4.5Kd + 0.2 wt.% of La alloy, reaching 98–104 HB, with subsequent decrease to 60 HB as the quenching temperature reaches 605 °С. The hardness of the unhardened alloy is 60 HB. The optimal quenching temperature for the AM4.5Kd + 0.2 wt.% of La alloy is in the range of 535–545 °С. This temperature corresponds to the highest hardness of the alloy and the microhardness of the aluminide.

The isothermal section of the phase diagram of Gd-Mn-Ga (≤50 at.%Ga) ternary system at 873K

The phase diagram of the Gd-Mn-Ga ternary system is a very important tool for the exploration and development of rare earth Heusler alloys with excellent physical properties, such as magnetic properties, half-metallic properties, ferromagnetic shape memory effect, magnetocaloric effect, ect. In this study, the alloy samples were prepared using a vacuum arc melting furnace, and the 873 K isothermal section of the Gd-Mn-Ga (≤50 at.%Ga) ternary alloy phase diagram was determined by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy spectrometry (EDS). The isothermal section consists of 22 single-phase regions, 44 two-phase regions, and 23 three-phase regions with the presence of 6 ternary compounds, GdMnGa, Gd2MnGa6, Gd2Mn15Ga2, Gd2Mn11Ga6, GdMn0.56Ga1.44, and GdMn0.37Ga1.63. The solid solubility ranges of Ga in β-Mn and Gd2Mn15Ga2 are 5.0–18.1 at.%Ga and 10.5–25.0 at.% Ga. The maximum solid solubility of Ga in α-Mn, GdMn12, and Gd6Mn23 are 2.0, 2.7, and 7.3 at.% Ga, respectively. The maximum solid solubility of Mn in GdGa2 is determined to be 13.1 at.% Mn.

Thermoelectric performance optimization of GeMnSbTe compounds through increasing the Mn solid solubility: Effects of the co-doping of rare earth elements

GeTe is a p-type thermoelectric (TE) material that exhibits a high ZT value and holds promise for a wide range of applications. In this study, a series of Ge0.86Mn0.1Sb0.04Te + 1 mol.% RE (Rare Earth elements = Er, Tm, Yb, Lu) compounds are synthesized through the melt-quenching method followed by fast-hot-pressing. Findings indicate that the TE properties are improved by simultaneously increasing the Seebeck coefficient and reducing the thermal conductivity, making the peak ZT value experiences an enhancement of 73%, while the average ZT value through 450–800 K shows an improvement of 70%. The solid solubility of Mn is significantly increased by the addition of the REs, that promotes the regulating effect of Mn on the energy band. A diverse range of microstructures including ordered atomic staggered arrays, van der Waals interstitials, dislocation enrichment, dislocation networks, nano precipitation phases with cavity structures, interstitial clusters, and vacancy clusters are introduced by REs, significantly contributing to the reduction of the κL. Thus, this study offers valuable insights and mechanism analysis into enhancing the properties of GeMnSbTe materials by incorporating REs, and proves that Tm has better thermoelectric performance optimization effect in this.

Synthesis, characterization and evaluation of novel manganese nanoclay polymer composite and nano‐MnO2 in wheat

AbstractBackgroundManganese (Mn) deficiency due to nutrient mining by high yielding cereal–cereal cropping patterns and forgetfulness of Mn fertilizer applications becomes potential challenge in crop production.AimNano‐enabled Mn fertilizers can be safer and more nutrient efficient than conventional Mn fertilizers (nutrient use efficiency ≈ 1%–3%). However, studies about nano‐Mn fertilizer synthesis and their behaviour in soil–plant system are rare.MethodsIn this study, two novel nano‐Mn fertilizers, that is nano‐MnO2 (NMO) and manganese nanoclay polymer composites (Mn‐NCPC), were synthesized, characterized (dynamic light scattering, X‐ray diffraction, Scanning electron microscopic and energy‐dispersive X‐ray, Fourier transform infrared spectroscopy etc.) and investigated for their impact on growth, yield and nutrient acquisition by wheat crop (Triticum aestivum L., variety HD‐2967) in a pot culture experiment. Treatment comprised 25%, 50% and 100% of recommended dose of Mn (RDMn) through NMO along with 100% RDMn through MnSO4·H2O (MS). Effect of exposure route was also investigated using foliar spray of NMO at tillering stage. Mn‐NCPC was found to be most efficient Mn fertilizer in terms of yield, Mn uptake and use efficiency by wheat crop.ResultsNano‐sized formulations improved the solubility of Mn in soil due to its higher active surface area (NMO) and slow‐release behaviour (Mn‐NCPC); thus, minimal losses happened due to the fixing of Mn in oxide/hydroxide forms. Application of 25% RDMn through NMO fertilizers maintained equitant diethylenetriamine pentaacetate Mn content to 100% RDMn through MnSO4·H2O. Mn‐NCPC stimulated the soil enzymatic activities, namely dehydrogenase, acid–alkaline phosphatase activities. Mn‐NCPC and NMO at 100% RDMn recorded 3.51% and 5.20% improvement in grain yield, respectively, when compared to MnSO4·H2O 100%.ConclusionsMn fertilizer doses can be reduced up to 25% of RDMn when applied through NMO or Mn‐NCPC fertilizers. However, effects of Mn‐NCPC and NMO need to be critically evaluated in long‐term field experiments in various cropping systems especially under cereal–cereal sequences for economic profitability and wide‐scale farmer's adaptability.

Temporal development of arsenic speciation and extractability in acidified and non-acidified paddy soil amended with silicon-rich fly ash and manganese- or zinc-oxides under flooded and drainage conditions

Oxides of silicon (Si), manganese (Mn), and zinc (Zn) have been used as soil amendments to reduce As mobility and uptake in paddy soil systems. However, these amendments are hypothesized to be affected differently depending on the soil pH and their effect on As speciation in rice paddy systems is not fully understood. Herein, we used a microcosm experiment to investigate the effects of natural Si-rich fly ash and synthetic Mn and Zn oxides on the temporal development of porewater chemistry, including aqueous As speciation (As(III), As(V), MMA, DMA, and DMMTA) and solid-phase As solubility, in a naturally calcareous soil with or without soil acidification (with sulfuric acid) during 28 days of flooding and subsequent 14 days of drainage. We found that soil acidification to pH 4.5 considerably increased the solubility of Si, Fe, Mn, and Zn compared to the non-acidified soil. Additions of Mn and Zn oxides decreased the concentrations of dissolved arsenite and arsenate in the non-acidified soil whereas additions of Zn oxide and combined Si–Zn oxides increased them in the acidified soil. The Si-rich fly ash did not increase dissolved Si and As in the acidified and non-acidified soils. Dimethylated monothioarsenate (DMMTA) was mainly observed in the acidified soil during the later stage of soil flooding. The initial 28 days of soil flooding decreased the levels of soluble and exchangeable As and increased As associated with Mn oxides, whereas the subsequent 14 days of soil drainage reversed the trend. This study highlighted that soil acidification considerably controlled the solubilization of Ca and Fe, thus influencing the soil pH-Eh buffering capacity, the solubility of Si, Mn, and Zn oxides, and the mobility of different As species in carbonate-rich and acidic soils under redox fluctuations.

Fine particle pollution during megafires contains potentially toxic elements

Wildfires that raged across Australia during the 2019–2020 ‘Black Summer’ produced an enormous quantity of particulate matter (PM) pollution, with plumes that cloaked many urban centres and ecosystems along the eastern seaboard. This has motivated a need to understand the magnitude and nature of PM exposure, so that its impact on both built and natural environments can be more accurately assessed. Here we present the potentially toxic fingerprint of PM captured by building heating, ventilation, and air conditioning filters in Sydney, Australia during the peak of the Wildfires, and from ambient urban emissions one year later (Reference period). Atmospheric PM and meteorological monitoring data were also assessed to determine the magnitude and source of high PM exposure. The wildfires were a major source of PM pollution in Sydney, exceeding the national standards on 19 % of days between November–February. Wildfire particles were finer and more spherical compared to Reference PM, with count median diameters of 892.1 ± 23.1 versus 1484.8 ± 96.7 nm (mean ± standard error). On an equal-mass basis, differences in potentially toxic elements were predominantly due to higher SO42−-S (median 20.4 vs 4.7 mg g−1) and NO3−-N (2.4 vs 1.2 mg g−1) in Wildfire PM, and higher PO43−-P (10.4 vs 1.4 mg g−1) in Reference PM. Concentrations of remaining elements were similar or lower than Reference PM, except for enrichments to F−, Cl−, dissolved Mn, and particulate Mn, Co and Sb. Fractional solubilities of trace elements were similar or lower than Reference PM, except for enhanced Hg (12.1 vs 1.0 %) and greater variability in Cd, Hg and Mn solubility, which displayed upper quartiles exceeding that of Reference PM. These findings contribute to our understanding of human and ecosystem exposures to the toxic components of mixed smoke plumes, especially in regions downwind of the source.

Atmospheric deposition of mineral dust and associated nutrients over the Equatorial Indian Ocean

Aerosols are potential supplier of nutrients to the surface water of oceans and can impact biogeochemical processes particularly in the remote locations. The nutrient data from atmospheric supply is poorly reported from the Indian Ocean region. In this study, we present atmospheric nutrients such as reactive nitrogen species (Nitrate, Ammonium, Organic nitrogen), micro-nutrients (e.g. Fe, Mn and Cu) concentration along with mineral dust in the aerosol samples collected over meridional transect during summer (April–May 2018) and monsoon (June–July 2019) months. A significant spatial variation of dust was observed during summer (0.6–22.8 μg m−3) and monsoon (2.8–25.1 μg m−3) months with a decreasing trend from north to south. Dust as well as other nutrient species shows a general north to south decreasing trend, however, no such trend was seen in the soluble trace elements (TEs) concentration. Anthropogenic species like NH4+ and nss-K+ were found below detection limit during monsoon campaign. The fractional solubility (in percentage) of Fe, Mn and Cu were estimated by measuring their concentration in ultrapure water leach which averaged around 0.99 ± 1.12, 31.0 ± 14.9 and 31.1 ± 25.4, respectively during summer and 0.09 ± 0.08, 6.0 ± 8.9, 16.7 ± 9.6, respectively, during monsoon period. Correlation of soluble Fe with total Fe and total acidic species suggest varying dust sources is an important controlling factor for the fraction solubility of Fe with negligible contribution from the chemical processing. However, a significant correlation was observed between total acid and fractional solubility of Mn and Cu suggest role of chemical processing in enhancement of their solubility. Dry deposition flux of aeolian dust was estimated for both campaign using Al concentration and relatively higher fluxes were observed for summer (12.6 ± 8.4 mg·m−2·d−1) and monsoon (8.7 ± 8.4 mg·m−2·d−1) months as compared to model based estimates reported in the literature. Contrastingly, estimated deposition flux of soluble Fe from both campaign displays relatively lower values as compared to model based results which underscores a need for re-evaluation of biogeochemical models with real-time data.

Trace mineral sources influence in vitro fermentation characteristics and trace mineral solubility.

Two experiments were conducted to determine: 1) the impact of strained rumen fluid (SRF) alone or SRF with particle-associated microorganisms (PAO) included and dilution on in vitro dry matter digestibility (DMD) and 2) the impact of trace mineral (TM) source on in vitro fermentation characteristics and TM solubility under simulated abomasal and intestinal conditions. In experiment 1, 3 cannulated steers were adapted to a diet formulated to meet the nutrient requirements for lactating dairy cows. Strained RF was obtained by straining rumen content through 2 layers of cheesecloth. Half of the remaining digesta was washed with McDougall's buffer and filtered through 2 layers of cheesecloth to obtain PAO. Both SRF and PAO were filtered again through 8 layers of cheesecloth. Strained RF was mixed with either McDougall's buffer (SRF) or PAO (SRF+ + PAO) at a ratio of 1:2 or 1:4 and incubated at 39 °C for 12h using the ground basal diet as the substrate. Digestibility of DM was greater in digestion tubes containing SRF and SRF + PAO at a 1:2 ratio. In experiment 2, 8 steers fitted with a ruminal cannula were blocked by body weight and assigned to 1 of the 2 treatment groups. Treatments consisted of 10mg Cu, 40mg Mn, and 60mg Zn/kg DM from either: 1) sulfate (STM) or 2) hydroxychloride (HTM) sources. Steers were housed in individual pens and fed the same diet as described in experiment 1. Dietary TM treatments were mixed with dried distiller grains and mixed in the diet, by hand, immediately after basal diet delivery. Dietary treatments were fed for 14 d. On day 15, SRF + PAO was collected from each steer (STM-RF and HTM-RF) and used in a series of in vitro crossover experiments. In vitro substrates (S) used were the ground diets consumed by the animals on each treatment (STM-S and HTM-S). Incubations containing HTM-S had greater (P < 0.01) total volatile fatty acid (VFA) concentration and propionic acid molar proportions, but lesser (P < 0.01) acetic acid molar proportions than STM-S. Rumen fluid from steers supplemented with HTM had a greater (P < 0.03) total VFA than STM-RF at 24h post incubation. After 12h post incubation, the molar proportion of propionic acid in HTM-RF was lesser (P = 0.04) than in STM-RF. After simulated abomasal digestion, soluble Mn concentration in HTM-S was greater (P < 0.01) than in STM-S. These data indicate that the source of TM can influence in vitro rumen fermentation characteristics and Mn solubility under simulated abomasal conditions.

Experimental factors influencing the bioaccessibility and the oxidative potential of transition metals from welding fumes.

Inhalation of welding fumes (WFs) containing high levels of transition metals (Cr, Cu, Fe, Mn, Ni…) is associated with numerous health effects including oxidative stress. However, the measurements of the oxidative potential (OP) and bioaccessibility of WF transition metals depend on several physicochemical parameters and may be subject to several experimental artifacts. In this work, we investigated the influence of the experimental conditions that may affect the bioaccessibility of transition metals and their OP on stainless-steel WF extracts. WFs were produced using a generation bench and sampled on filters. The soluble fraction of the metals was analysed. Two different extraction fluids mimicking physiological pulmonary conditions were studied: phosphate buffer and Hatch's solution. Three extraction times were tested to determine the optimal time for a significant OPDTT using the dithiothreitol (DTT) method. The storage conditions of WFs after filter sampling such as duration, temperature and atmospheric conditions were investigated. The results indicate that experimental conditions can significantly affect the OPDTT and metal bioaccessibility analyses. Cr, Cu and Ni show higher solubility in Hatch's solution than in the phosphate buffer. Mn is highly sensitive to DTT and shows close solubility in the two fluids. An extraction time of 0.5 h in phosphate buffer allows a better sensitivity to OPDTT, probably by limiting complexations, interactions between metals and precipitation. Storage time and temperature can influence the physical or chemical evolution of the WFs, which can affect their OPDTT and Mn solubility. However, storage under N2(g) limits these changes. On-line measurements of OPDTT could provide an alternative to filter sampling to overcome these artifacts.

Microstructure evolution and ductility improvement mechanism of Fe-containing recycled brass alloy after Mn addition

Excessive Fe precipitates and accumulates during the reusing process of scrap brass, which affects the service performance of recycled brass. Therefore, eliminating the agglomeration of the rich-iron phase in scrap brass is significant research in the preparation of high-performance recycled brass. In this study, 0.4 wt%--0.8 wt%Mn was added in recycled brass containing 0.8 wt% Fe to eliminate the influence of Fe-rich precipitation on the as-cast and extruded brass. The results show that the introduction of Mn inhibits the precipitation of clover-like precipitates in the matrix and reduces the volume fraction of Fe-rich precipitates in as-cast brass. At the same time, the presence of Mn promotes the solid solubility of Fe in the brass matrix, and the solid solubility of Fe and Mn in the α and β phases is significantly different. For extruded brass, its ductility is significantly improved with the introduction of Mn and the strengthening process comes from the synergistic effect of solid solution strengthening and fine crystal strengthening. This study provides insight into the preparation of high-performance regenerated brass alloy with good ductility by eliminating the agglomeration of the rich iron phase in scrap brass.

Plasticity of solid solution Al-Mn and Al-Mn-Si alloys

The influence of Mn and Si on the mechanical properties of solid solution Al-Mn and Al-Mn-Si alloys have been studied at 4 K, 78 K, and 298 K. The solute strengthening potency of the yield strength increases with decreasing temperature. The addition of Si stimulates the precipitation of Mn-containing dispersoids and decreases the solubility of Mn in the Al matrix, reducing the strengthening effect. The alloys exhibit Stage III of declining work hardening rate with the flow stress during the plastic flow at three temperatures. The mean slip length Λ in the work hardening model of Nabarro, Basinski, and Holt (NBH) evaluated from σΘ curves correlates with the scale of the microstructure. The strain rate sensitivity (SRS) measurements conducted at 78 K show positive SRS of Al and the alloys. At 298 K, one observes a change in SRS due to the change of the mechanism from solute-dislocation to dislocation-dislocation dominated interactions. Mn and Si decrease SRS at 298 K. Al-Mn-Si alloys exhibit negative SRS and jerk flow at a sufficiently low strain rate at 298 K. Analysis of the apparent activation volume, distance, and work has been conducted at 78 K and 298 K to understand the rate-controlling mechanisms. The results indicate that dislocation intersections are rate-limiting processes, but the atomistic mechanism of dislocation cutting varies vastly depending on the temperature and alloy composition. It is suggested that at 78 K, forest obstacles are passed by the formation of jogs and sequential activation of individual partials without making constriction to the perfect defect. At 298 K, the cutting involves constriction, the creation of jogs, and the creation of point defects at each intersection site. The calculated activation work and distance provide signatures of these processes.

Mono- and Co-Doped Mn-Doped CsPbCl3 Perovskites with Enhanced Doping Efficiency and Photoluminescent Performance.

To investigate the effect of Mn and other metal dopants on the photoelectronic performance of CsPbCl3 perovskites, we conducted a series of theoretical analyses. Our findings showed that after Mn mono-doping, the CsPbCl3 lattice contracted and the bonding strength increased, resulting in a more compact structure of the metal octahedral cage. The relaxation of the metal octahedral cage, along with the Jahn-Teller effect, results in a decrease in lattice strain between the octahedra and a reduction in the energy of the entire lattice due to the deformation of the metal octahedron. These three factors work together to reduce intrinsic defects and enhance the stability and electronic properties of CsPbCl3 perovskites. The solubility of the Mn dopant is significantly increased when co-doped with Ni, Fe, and Co dopants, as it compensates for the lattice strain induced by Mn. Doping CsPbCl3 perovskites reduces the band gap due to the decreased contributions of 3d orbitals from the dopants. Our analyses have revealed that strengthening the CsPbCl3 lattice and reducing intrinsic defects can result in improved stability and PL properties. Moreover, increasing Mn solubility and decreasing the bandgap can enhance the PLQY of orange luminescence in CsPbCl3 perovskites. These findings offer valuable insights for the development of effective strategies to enhance the photoelectronic properties of these materials.

SrO‐MnO/Ceramic: A Novel Bifunctional Catalyst for Biodiesel production via Simultaneous Transesterification‐Esterification of Waste Frying Oil

AbstractThe strontium‐manganese supported over ceramic was synthesized through wet impregnation method and investigated as a solid catalyst for its catalytic performance in transesterifying‐esterifying low‐grade waste frying oil with methanol in a batch reactor; parameters for synthesis of catalyst and transesterification reaction were also optimized. The maximum biodiesel yield of 93.66 % was attained by SrO‐MnO/Ceramic catalyst under normal process conditions. The synthesized catalyst reusability potential was also evaluated for 12 runs with regeneration carried out after the 7th run only and it revealed that the catalyst showed great stability for the initial five cycles offering yield of over 90 %. The fresh and used SrO‐MnO/Ceramic catalysts were characterized to address the mechanism of catalytic behavior and deactivation using scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), X‐ray diffraction (XRD), benzoic acid and n‐butylamine titration method, and Hammett indicators. The alteration in surface morphology; Mn solubility in glycerol and methanol; occupation of energetic centers by organics might be the reasons for diminished activity or deactivation of solid catalyst after repeated reuse.