Purpose Continuous wet granulation and drying require an adequate process control strategy to ensure the product quality. The most important critical quality attributes of dried granules are the granule size distribution and moisture content. Process analytical technologies (PATs) are available for real-time monitoring of moisture content by, e.g., near-infrared spectroscopy (NIRS), which requires additional installation and complex multivariate validation. Thus, a mass and energy balance (MEB) was derived for a vibrated fluidised bed dryer, which is part of the QbCon ® 1 intended for continuous wet granulation and drying. Method Process parameters that are frequently logged were used for the derivation of a MEB. The predicted MEB was compared with the measured loss-on-drying (LOD) for two different formulations. Results The model-derived data were in good agreement with the observed LOD, leading to RMSE values of 0.12–0.45. Conclusion The implemented MEB can predict the LOD over time and thus might be suitable as a soft sensor without the installation of additional sensors. The obtained energy flux gives insight into the heat transfer, and the derived energy balance might be used to determine the required energy under certain drying conditions.

The new thiostannate Na4Sn2S6 was prepared by directed crystal water removal from the hydrate Na4Sn2S6 center dot 5H(2)O at moderate temperatures. While the structure of the hydrate comprises isolated [Sn2S6](4-) anions, that of the anhydrate contains linear chains composed of corner-sharing SnS4 tetrahedra, a structural motif not known in thiostannate chemistry. This structural rearrangement requires bond-breakage in the [Sn2S6](4-) anion, movements of the fragments of the opened [Sn2S6](4-) anion and Sn-S-Sn bond formation. Simultaneously, the coordination environment of the Na+ cations is significantly altered and the in situ formed NaS5 polyhedra are joined by corner- and edge-sharing to form a six-membered ring. Time-dependent in situ X-ray powder diffraction evidences very fast rehydration into Na4Sn2S6 center dot 5H(2)O during storage in air atmosphere, but recovery of the initial crystallinity requires several days. Impedance spectroscopy demonstrates a mediocre room-temperature Na+ ion conductivity of 0.31 mu S cm(-1) and an activation energy for ionic transport of E-a=0.75 eV.

A highly unusual solid-state epitaxy-induced phase transformation of Na4SnS4 center dot 14H(2)O(I) into Na4Sn2S6 center dot 5H(2)O (II) occurs at room temperature. Ab initio molecular dynamics (AIMD) simulations indicate an internal acid-base reaction to form [SnS3SH](3-) which condensates to [Sn2S6](4-). The reaction involves a complex sequence of O-H bond cleavage, S-2-protonation, Sn-S bond formation and diffusion of various species while preserving the crystal morphology. In situ Raman and IR spectroscopy evidence the formation of [Sn2S6](4-). DFT calculations allowed assignment of all bands appearing during the transformation. X-ray diffraction and in situ H-1 NMR demonstrate a transformation within several days and yield a reaction turnover of approximate to 0.38%/h. AIMD and experimental ionic conductivity data closely follow a Vogel-Fulcher-Tammann type T dependence with D(Na)=6x 10(-14) m(2) s(-1) at T=300 K with values increasing by three orders of magnitude from -20 to +25 degrees C.

Abstract We present the convenient synthesis and characterization of the new ternary thiostannate Na4SnS4 (space group I41/acd ) by directed removal of crystal water molecules from Na4SnS4⋅14 H2O. The compound represents a new kinetically stable polymorph of Na4SnS4, which is transformed into the known, thermodynamically stable form (space group P4‾21c ) at elevated temperatures. Thermal co‐decomposition of mixtures with Na3SbS4⋅9 H2O generates solid solution products Na4−x Sn1−x Sb x S4 (x=0.01, 0.10) isostructural to the new polymorph (x=0). Incorporation of Sb5+ affects the bonding and local structural situation noticeably evidenced by X‐ray diffraction, 119Sn and 23Na NMR, and 119Sn Mössbauer spectroscopy. Electrochemical impedance spectroscopy demonstrates an enormous improvement of the ionic conductivity with increasing Sb content for the solid solution (σ 25°C=2×10−3, 2×10−2, and 0.1 mS cm−1 for x=0, 0.01, and 0.10), being several orders of magnitude higher than for the known Na4SnS4 polymorph.

We present new insights into the electrochemical properties of three metal sulfides MCr 2 S 4 ( M = Cr, Ti, Fe) probed as anode materials in sodium-ion batteries for the first time. The electrodes deliver decent reversible capacities and good long-term cycle stability, e.g., 470, 375, and 524 mAh g −1 are obtained after 200 cycles applying 0.5 A g −1 for M = Cr, Ti, and Fe, respectively. The reaction mechanisms are investigated via synchrotron-based X-ray powder diffraction and pair distribution function analyses. The highly crystalline educts are decomposed into Na 2 S nanoparticles and ultra-small metal particles during initial discharge without formation of intermediate NaCrS 2 domains as previously reported for CuCrS 2 and NiCr 2 S 4 . After a full cycle, the structural integrity of MCr 2 S 4 ( M = Cr, Ti, Fe) is not recovered. Thus, the Na storage properties are attributed to redox reactions between nanoscopic to X-ray amorphous conversion products with only local atomic correlations M···S/S···S in the charged and M···M/Na···S in the discharged state. Graphical Abstract

A highly unusual solid-state epitaxy-induced phase transformation of Na4 SnS4  ⋅ 14H2 O (I) into Na4 Sn2 S6  ⋅ 5H2 O (II) occurs at room temperature. Ab initio molecular dynamics (AIMD) simulations indicate an internal acid-base reaction to form [SnS3 SH]3- which condensates to [Sn2 S6 ]4- . The reaction involves a complex sequence of O-H bond cleavage, S2- protonation, Sn-S bond formation and diffusion of various species while preserving the crystal morphology. In situ Raman and IR spectroscopy evidence the formation of [Sn2 S6 ]4- . DFT calculations allowed assignment of all bands appearing during the transformation. X-ray diffraction and in situ 1 H NMR demonstrate a transformation within several days and yield a reaction turnover of ≈0.38 %/h. AIMD and experimental ionic conductivity data closely follow a Vogel-Fulcher-Tammann type T dependence with D(Na)=6×10-14  m2  s-1 at T=300 K with values increasing by three orders of magnitude from -20 to +25 °C.

Various electrode materials are considered for sodium-ion batteries (SIBs) and one important prerequisite for developments of SIBs is a detailed understanding about charge storage mechanisms. Herein, we present a rigorous study about Na storage properties of ultra-small Fe3S4 nanoparticles, synthesized applying a solvothermal route, which exhibit a very good electrochemical performance as anode material for SIBs. A closer look into electrochemical reaction pathways on the nanoscale, utilizing synchrotron-based X-ray diffraction and X-ray absorption techniques, reveals a complicated conversion mechanism. Initially, separation of Fe3S4 into nanocrystalline intermediates occurs accompanied by reduction of Fe3+ to Fe2+ cations. Discharge to 0.1 V leads to formation of strongly disordered Fe0 finely dispersed in a nanosized Na2S matrix. The resulting volume expansion leads to a worse long-term stability in the voltage range 3.0-0.1 V. Adjusting the lower cut-off potential to 0.5 V, crystallization of Na2S is prevented and a completely amorphous intermediate stage is formed. Thus, the smaller voltage window is favorable for long-term stability, yielding highly reversible capacity retention, e.g., 486 mAh g-1 after 300 cycles applying 0.5 A g-1 and superior coulombic efficiencies >99.9%. During charge to 3.0 V, Fe3S4 with smaller domains are reversibly generated in the 1st cycle, but further cycling results in loss of structural long-range order, whereas the local environment resembles that of Fe3S4 in subsequent charged states. Electrokinetic analyses reveal high capacitive contributions to the charge storage, indicating shortened diffusion lengths and thus, redox reactions occur predominantly at surfaces of nanosized conversion products.

In contrast to other cutting processes, adiabatic blanking typically features high blanking velocities (>3 m/s), which can lead to the formation of adiabatic shear bands in the blanking surface. The produced surfaces have excellent properties, such as high hardness, low roll-over, and low roughness. However, details about the qualitative and quantitative influence of significant process parameters on the quality of the blanked surface are still lacking. In the presented study, a variable tool is used for a systematic investigation of different process parameters and their influences on the blanked surface of a hardened 22MnB5 steel. Different relative clearances (1.67% to 16.67%), velocities (7 to 12.5 m/s), and impact energies (250 J to 1000 J) were studied in detail. It is demonstrated that a relative clearance of ≤6.67% and an impact velocity of ≥7 m/s lead to adiabatic shear band formation, regardless of the impact energy. Further, an initiated shear band results in the formation of an S-shaped surface. Unexpectedly, a low impact energy results in the highest geometric accuracy. The influence of the clearance, the velocity, and the impact energy on the evolution of adiabatic shear band formation is shown for the first time. The gained knowledge can enable a functionalization of the blanked surfaces in the future.

The pseudo-layered sulfide NiCr2S4 exhibits outstanding electrochemical performance as anode material in sodium-ion batteries (SIBs). The Na storage mechanism is investigated by synchrotron-based X-ray scattering and absorption techniques as well as by electrochemical measurements. A very high reversible capacity in the 500th cycle of 489 mAh g(-1) is observed at 2.0 A g(-1) in the potential window 3.0-0.1 V. Full discharge includes irreversible generation of Ni-0 and Cr-0 nanoparticles embedded in nanocrystalline Na2S yielding shortened diffusion lengths and predominantly surface-controlled charge storage. During charge, Ni-0 and Cr-0 are oxidized, Na2S is consumed, and amorphous Ni and Cr sulfides are formed. Limiting the potential window to 3.0-0.3 V an unusual nickel extrusion sodium insertion mechanism occurs: Ni2+ is reduced to nanosized Ni-0 domains, expelled from the host lattice, and is replaced by Na+ cations to form O3-type like NaCrS2. Surprisingly, the discharge and charge processes comprise Na+ shuttling between highly crystalline NiCr2S4 and NaCrS2 enabling a superior long-term stability for 3000 cycles. The results not only provide valuable insights for the electrochemistry of conversion materials but also extend the scope of layered electrode materials considering the reversible nickel extrusion sodium insertion reaction as new concept for SIBs.

The compound CuCrS 2 with a quasi-layered crystal structure was investigated as room temperature rechargeable sodium ion battery electrode. It exhibits an excellent performance as anode material with a high reversible capacity of 424 mAhg -1 at 700 mAg -1 after 200 cycles and a capacity retention of 98.6 % compared to the third cycle. Results of ex situ X-Ray diffraction experiments performed at different stages of discharge demonstrate that at the beginning of Na uptake Cu + cations are reduced to nanosized metallic Cu particles which are expelled from the host lattice. Simultaneously Na is inserted into the host material leading to formation of Na 0.7 Cu 0.15 CrS 2 with a significantly expanded interlayer space. Metallic Cu and Na 0.7 Cu 0.15 CrS 2 coexist at this stage of discharge. Increasing the amount of Na per formula unit leads to successive conversion to X-ray amorphous Cr, nanocrystalline Na 2 S and metallic Cu. The formation of highly disordered metallic Cr with domain sizes in the range of few nanometres is revealed by atomic pair distribution function analysis. During the charge process the nanocrystalline Cu particles are retained and Na 0.7 Cu 0.15 CrS 2 is at least partially reformed. The finely distributed Cu particles dramatically improve the long-time stability as evidenced by comparison of the electrochemical behaviour of mere NaCuCrS 2 . We demonstrated that CuCrS 2 is an excellent anode material for sodium ion storage. A superior high and stable capacity of 424 mAhg -1 is achieved at high C rates in the 200 th cycle. The evolution of nanocrystalline metallic Cu particles during the first discharge leads to an improved electron transport, which explains the superior rate stability compared to other pure transition metal sulfides. Ex situ XRD analyses elucidated a successive conversion of CuCrS 2 to Cu and the intermediate phase Na 0.7 Cu 0.15 CrS 2, followed by a full conversion. The formation of Na 2 S and metallic Cu could be clearly demonstrated by ex situ XRD measurements, while PDF analysis unveiled the presence of nano-scaled, most probably highly disordered metallic Cr in the discharged state. During the charge process Na 2 S disappears while nanocrystalline Cu is still present and Na 0.7 Cu 0.15 CrS 2 is reformed. These results underline that ternary compounds might be superior compared to mere binary compounds in terms of rate and long-time cycle stability. Get out of my way: The sodium – copper extrusion mechanism of CuCrS 2 was studied using ex situ XRD measurements, Rietveld refinements and PDF analysis. CuCrS 2 exhibits a very complex phase transition in the early stage of Na uptake to form Na 0.70 Cu 0.15 CrS 2 followed by the full conversion to Cu, Cr and Na 2 S. This reaction is highly reversible leading to a capacity of 424 mAhg -1 after the 200 th cycle.

The front cover artwork is provided by the group of Prof. Bensch at the inorganic chemistry department of Christian-Albrechts-University Kiel (Germany). The image illustrates the copper – sodium extrusion mechanism in CuCrS2 during the first step of sodium uptake. Additionally, the results of ex-situ X-ray diffraction measurements and pair distribution function measurements are displayed.More information can be found in the article by M. Krengel et al. (DOI: 10.1002/batt.201800039).

Succinic acid (SA) was esterified with ethanol using Candida antarctica lipase B immobilized on acrylic resin at 40 and 50 °C. Enzyme activity in the reaction medium was assured prior to reaction experiments. Reaction-equilibrium experiments were performed for varying initial molalities of SA and water in the reaction mixtures. This allowed calculating the molality-based apparent equilibrium constant K m as function of concentration and temperature. K m was shown to depend strongly on the molality of water and SA as well as on temperature. It could be concluded that increasing the molality of SA shifted the reaction equilibrium towards the products. Water had a strong effect on the activity of the enzyme and on K m . The concentration dependence of K m values was explained by the activity coefficients of the reacting agents. These were predicted with the thermodynamic models Perturbed-Chain Statistical Associating Fluid Theory (PC-SAFT), NRTL, and Universal Quasichemical Functional Group Activity Coefficients (UNIFAC), yielding the ratio of activity coefficients of products and reactants K γ . All model parameters were taken from literature. The models yielded K γ values between 25 and 115. Thus, activity coefficients have a huge impact on the consistent determination of the thermodynamic equilibrium constants K th. Combining K m and PC-SAFT-predicted K γ allowed determining K th and the standard Gibbs energy of reaction as function of temperature. This value was shown to be in very good agreement with results obtained from group contribution methods for Gibbs energy of formation. In contrast, inconsistencies were observed for K th using K γ values from the classical gE-models UNIFAC and NRTL. The importance of activity coefficients opens the door for an optimized reaction setup for enzymatic esterifications.

Le bois est a la fois un puits de carbone terrestre majeur et une ressource naturelle renouvelable essentielle pour l’Homme. Les cellules de bois sont produites par le cambium, un tissu indifferencie qui s’intercale entre l’ecorce et le bois deja forme. Dans les regions temperees, on apercoit facilement sur la section d’un tronc d’arbre abattu une succession d’anneaux de croissance annuels, ou cernes. La structure radiale d’un cerne est caracteristique et se repete quasi inchangee d’un cerne a l’autre. Malgre son importance pour les ecosystemes, la formation du bois est mal comprise. On ne connait pas les mecanismes regulant la proliferation des cellules de bois et permettant d’aboutir a la structure typique des cernes. Plusieurs travaux experimentaux suggerent cependant que des gradients de concentration de signaux biochimiques pourraient guider les cellules dans leur differenciation en leur apportant une information positionnelle. Pour tester cette hypothese des gradients morphogenetiques, j’ai suivi une approche par modeles biophysiques. Ces modeles incluent les processus de division et d’elargissement cellulaires, ainsi que leurs consequences sur le transport des signaux. Les signaux sont supposes fournir une information positionnelle aux cellules et determiner le taux d’expansion de chaque cellule. J’ai pu demontrer que l’hypothese des gradients morphogenetiques expliquait de nombreux aspects de la formation du bois. Elle se revele neanmoins insuffisante pour reproduire precisement la structure anatomique du bois forme. Dans l’ensemble, les resultats presentes montrent que le cambium est un tissu dont la dynamique est complexe et largement autonome.