Sn Interactions Research Articles

Liquid Bi-Sb-Sn Electrodes with Synergistic Stabilization Mechanism for Long-Lifespan Sodium-Based Liquid Metal Batteries.

Sodium-based liquid metal batteries are well suited for stationary energy storage due to their long life, intrinsic safety, and ease of scale-up. However, the irreversible alloying reaction between the positive current collector (PCC) and the cathodes at high temperatures leads to severe capacity degradation of the battery, severely limiting its scale-up application. In this work, a Bi-Sb-Sn alloy cathode based on a synergistic stabilization mechanism was designed for the first time. Due to the density difference of Bi, Sb, and Sn and the compatibility difference of Bi and Sn with the PCC, a part of Bi and Sn is spontaneously distributed in the region close to the PCC. The protection of Sb is realized by blocking the contact of Sb with the PCC as well as removing the PCC material dissolved in the cathode to prevent the loss of active material. Based on such protection, the Na||Bi36Sb24Sn40 cell maintained 99% Coulombic efficiency for 450 cycles at a rate of 0.75 C, with a capacity retention of 99.56% and a capacity decay rate of 0.001% per cycle. In addition, the interaction of Bi, Sb, and Sn during discharge also promotes capacity release and energy efficiency. At 0.3 C, the Na||Bi36Sb24Sn40 cell achieved 89% capacity utilization and 82% energy efficiency. These results provide an idea for the design of other batteries based on liquid metal electrodes.

New constraints on the gamma-ray and high energy neutrino fluxes from the circumstellar interaction of SN 2023ixf

The recent supernova, SN 2023ixf, one of the closest observed type II SNe has revealed the presence of a dense circumstellar material (CSM). Interaction of the SN ejecta with this dense CSM might create high energy protons of PeV energies through shock acceleration. These accelerated protons then colliding with the CSM (inelastic pp collision) can produce secondaries such as high energy gamma-rays and neutrinos. However, no gamma-rays and neutrinos have been detected by Fermi-LAT and IceCube from this event. Fermi-LAT has placed an upper limit on the gamma-ray flux above 100 MeV to be 2.6 × 10-11 erg cm-2 s-1. On the other hand, IceCube's upper limit on muon neutrino flux is 7.3 × 10-2 GeV cm-2. Taking these limits into account and using the shock-CSM properties derived from multi-wavelength observations, we obtain new upper limits on the gamma-ray (10-11 erg cm-2 s-1) and neutrino (10-3 GeV cm-2) fluxes from SN 2023ixf produced via the pp interaction channel. While we found the gamma-ray flux to be consistent with Fermi-LAT's upper limit, the neutrino flux is found to be about 2 orders of magnitude smaller than the IceCube's upper limit. We further analyse the detection prospects of such secondary signals from future SN 2023 like events with upcoming detectors, CTA and IceCube-Gen2 and found to have great discovery potential, if any similar event occurs within 7 Mpc.

Variations in soil carbon, nitrogen, and phosphorus concentrations and stoichiometry with stand age in Acacia hybrid plantations in Southern Vietnam

Abstract. Chau M, Quy N, Xu X, Hung B, Cuong LV, Ngoan T, Nguyen T. 2024. Variations in soil carbon, nitrogen, and phosphorus concentrations and stoichiometry with stand age in Acacia hybrid plantations in Southern Vietnam. Biodiversitas 25: 565-573. Soil Carbon (C), Nitrogen (N), and Phosphorus (P) contents are the three most critical soil nutrient elements required for plant growth and development, and their ecological stoichiometric ratios are significant indicators for understanding soil nutrient balance and cycling. This study was conducted to probe variations in the soil organic C (SC), total N (SN), and total P (SP) contents and stoichiometry at five soil depths (0-20, 20-40, 40-60, 60-80, and 80-100 cm) in Acacia hybrid plantations of five different ages (2-, 4-, 6-, 8-, and 10-year-old plantations) in Langa-Dongnai Forestry Company, Southern Vietnam. The results showed that forest age and soil depth substantially impacted soil nutrient contents and their stoichiometric characteristics. The concentrations of SC, SN, and SP as well as C/N, C/P, and N/P ratios increased as the forest stand age increased. The contents of SC, SN, and SP reduced with soil depth, indicating an obvious soil “surface-aggregation” phenomenon. The nutrient restriction varied based on forest stand development, shifting from restricted nitrogen in the earlier growth periods of trees to restricted phosphorus in the later growth periods. The findings demonstrate that to resolve the issue of restricted availability of these nutrient indexes, additional nitrogen should be supplied during earlier growth periods and additional phosphorus during later growth periods. The results further emphasize the importance of understanding SC, SN, and SP interactions and nutritional limitations and provide relevant theoretical support for sustainable Acacia hybrid plantation management in the Southern region.

Hypercoordination by multiple dangling benzylmethoxy ligands in highly crowded triaryltin bromide [(2-MeOCH2C6H4)3]SnBr and diaryltin mixed halides [(2-MeOCH2C6H4)2]SnBrCl.

The reaction between the Grignard reagent formed between Mg and 2-bromobenzylmethyl ether and SnCl4 produced four products: [2-(MeOCH2)C6H4]3SnBr (1), [2-(MeOCH2)C6H4]2SnX2 (2, X2 = Br2 (a) and BrCl (b)), [{2-(MeOCH2)C6H4}3Sn]2 (3), and [{2-(MeOCH2)C6H4}2SnBr]2O (4). In the case of 1, two of the three dangling arm O atoms coordinate to the central tin atom with O-Sn internuclear distances of 2.53 (O1) and 2.91 (O2) Å, the shorter interaction being trans to the Br atom, the other trans to a phenyl carbon atom. In the case of 2 the resulting hexacoordinate structure exhibits two very short O---Sn interactions of 2.42 and 2.50 Å, well below the sum of the VdW radii of O and Sn, 3.69 Å. The sterically crowded ditin compound 3 was obtained in trace amounts and the structure demonstrates no dangling O---Sn interactions. General changes in structure compared to other distannane systems are reflective of the great steric crowding. Distannoxane 4, has a Sn-O-Sn bond angle of 148.1(2)o which is larger compared to other distannoxane structures. The intermolecular interactions between Sn---O 2.470(3) and 2.521(3)Å and 2.665(3) and 2.629(3)Å for Sn1 and Sn2 respectively are responsible for a distorted octahedral geometry around the two tin atoms.

Early Spectroscopy and Dense Circumstellar Medium Interaction in SN 2023ixf

We present the optical spectroscopic evolution of SN 2023ixf seen in subnight cadence spectra from 1.18 to 15 days after explosion. We identify high-ionization emission features, signatures of interaction with material surrounding the progenitor star, that fade over the first 7 days, with rapid evolution between spectra observed within the same night. We compare the emission lines present and their relative strength to those of other supernovae with early interaction, finding a close match to SN 2020pni and SN 2017ahn in the first spectrum and SN 2014G at later epochs. To physically interpret our observations, we compare them to CMFGEN models with confined, dense circumstellar material around a red supergiant (RSG) progenitor from the literature. We find that very few models reproduce the blended N iii (λλ4634.0,4640.6)/C iii (λλ4647.5,4650.0) emission lines observed in the first few spectra and their rapid disappearance thereafter, making this a unique diagnostic. From the best models, we find a mass-loss rate of 10−3–10−2 M ⊙ yr−1, which far exceeds the mass-loss rate for any steady wind, especially for an RSG in the initial mass range of the detected progenitor. These mass-loss rates are, however, similar to rates inferred for other supernovae with early circumstellar interaction. Using the phase when the narrow emission features disappear, we calculate an outer dense radius of circumstellar material R CSM,out ≈ 5 × 1014 cm, and a mean circumstellar material density of ρ = 5.6 × 10−14 g cm−3. This is consistent with the lower limit on the outer radius of the circumstellar material we calculate from the peak Hα emission flux, R CSM,out ≳ 9 × 1013 cm.

Non-Fermi-Liquid Behavior of Superconducting SnH4.

The chemical interaction of Sn with H2 by X-ray diffraction methods at pressures of 180-210GPa is studied. A previously unknown tetrahydride SnH4 with a cubic structure (fcc) exhibiting superconducting properties below TC = 72 K is obtained; the formation of a high molecular C2/m-SnH14 superhydride and several lower hydrides, fcc SnH2 , and C2-Sn12 H18 , is also detected. The temperature dependence of critical current density JC (T) in SnH4 yields the superconducting gap 2Δ(0)= 21.6 meV at 180GPa. SnH4 has unusual behavior in strong magnetic fields: B,T-linear dependences of magnetoresistance and the upper critical magnetic field BC2 (T) ∝ (TC - T). The latter contradicts the Wertheimer-Helfand-Hohenberg model developed for conventional superconductors. Along with this, the temperature dependence of electrical resistance of fcc SnH4 in non-superconducting state exhibits a deviation from what is expected for phonon-mediated scattering described by the Bloch-Grüneisen model and is beyond the framework of the Fermi liquid theory. Such anomalies occur for many superhydrides, making them much closer to cuprates than previously believed.

Dual-Coordination-Induced Poly(vinylidene fluoride)/Li6.4Ga0.2La3Zr2O12/Succinonitrile Composite Solid Electrolytes Toward Enhanced Rate Performance in All-Solid-State Lithium Batteries.

Pursuing high energy and power density in all-solid-state lithium batteries (ASSLBs) has been the focus of attention. However, due to their inferior ion transport, their rate performance is limited compared to traditional lithium-ion batteries. Herein, a dual-coordination mechanism is first proposed to construct a high-performance poly(vinylidene fluoride)/Li6.4Ga0.2La3Zr2O12/succinonitrile (PVDF/LLZO/SN) composite solid electrolyte. The dual-coordination interactions of SN with both LLZO and Li+ in lithium salts allow SN to act like a branched chain of PVDF, realizing an increase in the free volume of the composite electrolyte. Meanwhile, SN molecules are immobilized within the electrolyte membrane by coordinating with LLZO, ensuring good interfacial stability. Profiting from the dual-coordination mechanism, the PVDF/LLZO/SN composite solid electrolyte combines enhanced electrochemical performance and interfacial compatibility. When applied to ASSLBs, the composite solid electrolyte enables the battery to operate at rates up to 6 C. The LiFePO4/Li batteries operated at 4 C can still deliver a high capacity retention rate of 96.4% after 50 cycles. Notably, these batteries also exhibit good long-cycle stability. After 500 cycles at 0.5 C, the discharge capacity was maintained at 145.9 mAh g-1.

Optoelectronics of Atomic Metal-Semiconductor Interfaces in Tin-Intercalated MoS2.

Metal-semiconductor interfaces are ubiquitous in modern electronics. These quantum-confined interfaces allow for the formation of atomically thin polarizable metals and feature rich optical and optoelectronic phenomena, including plasmon-induced hot-electron transfer from metal to semiconductors. Here, we report on the metal-semiconductor interface formed during the intercalation of zero-valent atomic layers of tin (Sn) between layers of MoS2, a van der Waals layered material. We demonstrate that Sn interaction leads to the emergence of gap states within the MoS2 band gap and to corresponding plasmonic features between 1 and 2 eV (0.6-1.2 μm). The observed stimulation of the photoconductivity, as well as the extension of the spectral response from the visible regime toward the mid-infrared suggests that hot-carrier generation and internal photoemission take place.

Supramolecular architectures in novel diphenyl(aryl)tin(IV) chlorides

The diphenyl(aryl)tin(IV) chloride [2-{(CH2O)2CH)}C6H4]SnPh2Cl (1) was prepared reacting [2-{(CH2O)2CH)}C6H4]Li with Ph2SnCl2. Hydrolysis of 1 with p-toluenesulfonic acid as a proton source gave [2-(OCH)C6H4]SnPh2Cl (2), which in turn was reacted with 2-(aminomethyl)pyridine, benzidine, 1-aminopyrene, in the absence of a solvent or catalyst, to afford the mono- or bimetallic species [2-(2′-PyCH2NCH)C6H4]SnPh2Cl (3), ClSnPh2[2-C6H4(4-CHN-1,1′-C6H4C6H4-4′-NCH)-2′-C6H4]Ph2SnCl (4) and [2-(C16H12NCH)C6H4]SnPh2Cl (5) (Py = pyridyl, C16H12 = pyrene). The compounds were characterized by multinuclear NMR spectroscopy and mass spectrometry in solution and IR spectroscopy in solid state. The molecular structures for compounds 1–5 were established by single-crystal X-ray diffraction. For all compounds the metal center is pentacoordinated with a distorted trigonal bipyramidal geometry and a (C,E)C2SnX core (E = O, Nimine) as a result of intramolecular E→Sn interactions. The presence of CH···Cl and CH···π (Phcentroid, Pycentroid, Pyrenecentroid) intermolecular interaction led to the formation of supramolecular associations in solid state for all compounds, thus, ribbon-like polymer occurs in crystal of 1, 2D layers arise in the case of 2 and 4, and complex 3D architectures are found in 3 and 5.

Synthesis, characterization, and analysis of intermolecular interactions of isostructural diorganotin compounds containing enantiomeric 1,1-dithioligands

The reaction of enantiomerically pure (+) and (−) menthol as well as (R)-(+)- and (S)-(−)N-benzyl-1-phenylethylamine with carbon disulfide in presence of potassium hydroxide yielded, respectively, chiral xanthate and dithiocarbamates as their potassium salts. These chiral 1,1-dithioligands were reacted with diphenyltin dihalides to produce four enantiomeric and isostructural pairs of diorganotin complexes of formula (+)-[SnPh2{xanMEN}Cl] (1), (−)-[SnPh2{xanMEN}Cl] (1m), (+)-[SnPh2{xanMEN}Br] (2), (−)-[SnPh2{xanMEN}Br] (2m), (+)-[SnPh2{dtcBPE}Cl] (3), (−)-[SnPh2{dtcBPE}Cl] (3m), (+)-[SnPh2{dtcBPE}Br] (4), and (−)-[SnPh2{dtcBPE}Br] (4m). The 119Sn{1H} NMR data and the X-ray single-crystal diffraction studies of the eight heteroleptic compounds confirmed the anisobidentate pattern of the {(RnECS2}− (E = O, n = 1; E = N, n = 2) monoanionic ligand. The presence of halides and sulfur atoms enhanced the formation of CH⋯X, S⋯H, S⋯S, and pi⋯H non-covalent interactions in the crystalline state. A Hirshfeld surface analysis was carried out to identify these significant intermolecular contacts in the complexes. The less hindered tin atom in the xanthate complexes displayed a CS⋯X–Sn interaction of attractive nature.

Propane Dehydrogenation over PtSn/Al2O3 Catalysts: Influence of Urea to Al(NO3)3·9H2O Ratio

Al2O3 supports were synthesized by the hydrothermal method and PtSn/Al2O3 catalysts were prepared by incipient-wetness impregnation method. The influence of the ratio of urea to Al(NO3)3·9H2O on the structure and catalytic performance for propane dehydrogenation was investigated. The catalysts were characterized by XRD, N2 adsorption–desorption, SEM, H2-TPR, NH3-TPD and Raman. The results show that the ratios of urea to Al(NO3)3·9H2O influence the morphology and phy-chemical properties of Al2O3 support, which influence the dispersion of PtSn active sites and the interaction of Pt and Sn on PtSn/Al2O3 catalysts. The PtSn/Al2O3-9 catalyst possesses the highest interaction of Pt and Sn, which result in high dispersion of active sites. The PtSn/Al2O3-9 catalyst shows high propane conversion and low deactivation rate among these catalysts.

English

Chickpea is a major legume grown in Kenya. The agronomic performance, nodulation ability and grain crude protein are not fully exploited. Field experiments were conducted at Embu, Kenya to determine the effect of plant spacing and N-fertilizer rates on nodulation and protein content of selected chickpea varieties. A split-split plot design was used and replicated three times. Treatments consisted of main factor, variety in four levels (Saina K, Mwanza 2, Chania I, Chania III), sub factor, spacing in three levels (S1: 50 x 10; S2: 50 x 20; S3: 50 x 30 cm), and sub-sub factor, nitrogen  fertilizer rates in four levels of (0; 30; 60; 90 kg ha-1). Data on nodulation and CP was subjected to GLM. Spacing and N-fertilizer rates significantly affected nodule numbers, fresh weight and their sizes. Mwanza 2 x 50x10 cm x N30 posted highest nodule numbers while Chania III had highest protein content. Interactions of VS, VN, SN and VSN had no consistent pattern under nodule factors but were highly significant in percent CP. Hence, optimal interactive effects of VSN can improve nodulation factors and CP of chickpea. The information will help growers make informed decisions, and researchers in developing improved varieties. Key words: Chickpea, variety, spacing, N-fertilizer, nodulation, crude protein

Synthesis, Structure, and Bonding Properties of Hypercoordinate Triorganotin Compounds Featuring Three O→Sn Interactions

AbstractHere, heptacoordinate and hexacoordinate triorganotin compounds [o‐{(Ph2)(O)P}C6H4]3SnX (X=F (2 a), Cl (2 b), Me (2 f)) featuring three O→Sn interactions were synthesized. Chloro (2 b) and methyl (2 f) compounds were obtained from the oxygenation of the heptacoordinate triorganotin compounds {o‐(Ph2P)C6H4}3SnX (X=Cl (1 b), Me (1 f)) bearing three P donors. The fluorination of 2 b using tetrabutylammonium fluoride (TBAF) yielded the fluoro analogue 2 a. Structural studies were performed on a series of hypercoordinate triorganotin compounds, 2. The chloro analogue (2 b) exhibited a hexacoordinate geometry attributed to the Sn−Cl bond cleavage, where the highly electrophilic stannyl cation was stabilized by three O donors. In contrast, both the fluoro (2 a) and methyl (2 f) analogues exhibited heptacoordinate structures. Although 2 f adopted a tricapped tetrahedral geometry, 2 b is classified to adopt a distinctly rare bicapped trigonal pyramidal geometry featuring one strong LP(O)→σ*(Sn−F) interaction and two weak LP(O)→σ*(Sn−C) interactions (LP: lone pair electrons). The origin of the structural alternations depending on the substituent is discussed using density functional theory (DFT) calculations.

Promotional Effect of Ni−Sn Interaction over Ni Supported on Sn‐incorporated MCM‐41 Catalysts for CO2 Reforming of CH4

AbstractSintering of active Ni sites and deposition of coke remain challenging issues for catalytic dry reforming of methane. Herein, Ni supported on the Sn‐incorporated MCM‐41 catalysts were synthesized and tested for DRM process. The structural and physicochemical properties of fresh and spent samples were studied by N2 adsorption‐desorption, XRD, H2‐TPR, XPS, TEM, STEM‐EDS, Raman, and TGA techniques. It was revealed that Sn addition improved the dispersion and decreased the size of active Ni nanoparticles by tuning the charger transfer between Ni and Sn. The formation of Ni−SnOx interface provides more possibilities to activate CO2. The best results were obtained by 2Ni/Sn−MCM‐41 sample with the Ni/Sn mole ratio of 2 : 1, contributing CH4 conversion of 95% and CO2 conversion of 94% at 800 °C. Moreover, the presence of Sn increased the resistance to sintering of Ni‐based catalysts during the severe conditions, thereby the Ni nanoparticle size only appeared a slight growth after 32 h TOS. Combined with the characterization of the spent 2Ni/Sn−MCM‐41 sample, it was revealed that the coke deposition of the deactivated catalyst was dominated by amorphous carbon, which could be responsible for the desirable regeneration ability of the catalyst.

Two coordination compounds of SnCl2 with 4-methyl-pyridine N-oxide.

In the solid-state structures of catena-poly[[di-chlorido-tin(II)]-μ2-(4-methyl-pyridine N-oxide)-κ2 O:O], [SnCl2(C6H7NO)] n , 1, and di-chlorido-bis-(4-methyl-pyridine N-oxide-κO)tin(II), [SnCl2(C6H7NO)2], 2, the bivalent tin atoms reveal a seesaw coordination with both chlorine atoms in equatorial and the Lewis base mol-ecules in axial positions. While the Sn-Cl distances are almost identical, the Sn-O distances vary significantly as a result of the different bonding modes (μ2 for 1, μ1 for 2) of the 4-methyl-pyridin-N-oxide mol-ecules, giving rise to a one-dimensional coordination polymer for the 1:1 adduct, 1, and a mol-ecular structure for the 1:2 adduct, 2. The different coordination modes also influence the bonding parameters within the almost planar ligand mol-ecules, mostly expressed in N-O-bond lengthening and endocyclic bond-angle widening at the nitro-gen atoms. Additional supra-molecular features are found in the crystal structure of 2 as two adjacent mol-ecules form dimers via additional, weak O⋯Sn inter-actions.

Theoretical Insights into the Structural Differences between Organic and Inorganic Amines/Ethers.

The contrasting geometrical features between organic and inorganic counterparts of amines and oxanes are explained in terms of an offset between attractive (donor-acceptor) and repulsive (donor-donor) interactions. Natural bond orbital (NBO) calculations carried out at the density functional theory level of theory reveal that hyperconjugative effects in the organic amines and ethers are overcome by repulsive interactions occurring between the lone pair on the nitrogen/oxygen atom and the adjacent σ(C-R) bond orbitals. Although displaying lower energies than in the corresponding organic derivatives, the LP(X) → σ*(E-R) (X = N, O; E = Si, Ge, Sn) interactions in heavier counterparts overcome the LP(X)···σ(E-R) repulsions, impacting thus their structural behavior. In addition, NBO deletion optimizations emphasize that among hyperconjugations, back-bonding effects of the LP(X) → d(E) type dictate to a lesser extent the anomalous structures of the inorganic amines and oxanes.

Novel azaborastannylenes by DFT

We have reached novel borastannylenes with an unprecedented common frame work that can accommodate up to five nitrogen heteroatoms. All species appear as ground state minima on their energy surface, for showing no negative force constant. Singlets 7-boratricyclo[1.1.1.01,7.07,3.07,5]hexa-2-stannylenes (1s-20s) are ground states and more stable than their corresponding triplets (1t-20t). They are compared and contrasted with respect to their geometrical parameters, stability (ΔΕs-t), heat of hydrogenation (ΔEH), nucleophilicity (N), electrophilicity (ω), and isodesmic reactions at B3LYP/AUG-cc-pVTZ//B3LYP/6–311++G** level of theory. The highest stability belong to the singlet 1,3-diaza-7-boratricyclo[1.1.1.01,7.07,3.07,5]hexa-2-stannylene (5) which shows the highest value of ΔEs-t. Boracyclics singlet 1,4,6-triaza-7-boratricyclo[1.1.1.01,7.07,3.07,5]hexa-2-stannylene (14s) with coordinate covalent bond between nitrogen and stannylene center and 1,4,5,6-teraaza-7-boratricyclo[1.1.1.01,7.07,3.07,5]hexa-2-stannylene (18s) with high LPN → LP*Sn interactions have low ω. Also, the highest band gap (ΔΕHOMO–LUMO) belong to theirs. Our investigation introduces novel stannylene with possible applications in chemistry such as semiconductors, cumulated multi-dentate legends, etc.

One-step electrodeposition of cauliflower-like Ni–Fe–Sn particles as a highly-efficient electrocatalyst for the hydrogen evolution reaction

Herein, a Ni–Fe–Sn coating was synthesized in-situ on Ni mesh by one-step electrodeposition at different durations. The Ni–Fe–Sn60 electrode obtained after 1 h deposition exhibits cauliflower-like morphology and the best electrocatalytic properties for the hydrogen evolution reaction (HER) compared to other electrodes. The electrode requires an overpotential of 43 mV at a current density of 10 mA cm−2 and a small Tafel slope of 70 mV dec−1 in a 1 M KOH solution. Moreover, the electrode shows outstanding stability in prolonged electrolysis and overall water splitting performance, generating a current density of 93 mA cm−2 at 1.8 V, which is thrice that of an industry electrode. This electrocatalytic activity is ascribed to the high active surface area produced by the cauliflower-like Ni–Fe–Sn particles and the synergistic interaction of Ni, Fe and Sn. The simple synthesis method and excellent performance endow this electrode with great potential for large-scale applications.

Outside the Wall: Hydrodynamics of Type I Supernovae Interacting with a Partially Swept-up Circumstellar Medium

Abstract Explaining the observed diversity of supernovae (SNe) and the physics of explosion requires knowledge of their progenitor stars, which can be obtained by constraining the circumstellar medium (CSM). Models of the SN ejecta colliding with the CSM are necessary to infer the structure of the CSM and tie it back to a progenitor model. Recent SNe I revealed CSM concentrated at a distance r ∼ 1016 cm, for which models of SN interaction are extremely limited. In this paper, we assume the concentrated region is a “wall” representing swept-up material, and unswept material lies outside the wall. We simulate one-dimensional hydrodynamics of SNe Ia and Ib impacting 300 unique CSM configurations using RT1D, which captures the Rayleigh–Taylor instability. We find that the density ratio between the wall and ejecta—denoted A 0 or “wall height”—is key, and higher walls deviate more from self-similar evolution. Functional fits accounting for A 0 are presented for the forward-shock radius evolution. We show that higher walls have more degeneracy between CSM properties in the deceleration parameter, slower shocks, deeper-probing reverse shocks, slower shocked ejecta, less ejecta mass than CSM in the shock, and more mixing of ejecta into the CSM at early times. We analyze observations of SN 2014C (Type Ib) and suggest that it had a moderately high wall (10 ≲ A 0 ≲ 200) and wind-like outer CSM. We also postulate an alternate interpretation for the radio data of SN 2014C, that the radio rise occurs in the wind rather than the wall. Finally, we find that hydrodynamic measurements at very late times cannot distinguish the presence of a wall, except perhaps as an anomalously wide shock region.

Microwave induced one-pot conversion of d-glucose to 5-hydroxymethylfurfural by a novel sulfate-functionalized Sn-red mud catalyst

Sn doped and sulfate functionalized red mud produced excellent catalytic activity and stability owing to the synergistic interaction of Sn with components of red mud and enhanced acidic characteristics.