Solid Transformation Research Articles

In situ mapping of chemical segregation using synchrotron x-ray imaging

Abstract

Spatial Skills Associated With Block-Building Complexity in Preschoolers.

Block building is a popular play activity among young children and is also used by psychologists to assess their intelligence. However, little research has attempted to systematically explore the cognitive bases of block-building ability. The current study (N = 66 Chinese preschoolers, 32 boys and 34 girls; mean age = 4.7 years, SD = 0.29, range = 3.4 to 5.2 years) investigated the relationships between six measures of spatial skills (shape naming, shape recognition, shape composition, solid figure naming, cube transformation, and mental rotation, with the former four representing form perception and the latter two representing visualization) and block-building complexity. Correlation results showed that three of the four measures of form perception (shape naming, shape recognition, and shape composition) were significantly and positively correlated with block-building complexity, whereas the two measures of visualization were not. Results from regression models indicated that shape recognition and shape composition, as well as shape-recognition-by-gender interaction, were unique predictors of children’s block-building complexity. These findings provide preliminary evidence for the basic spatial skills underlying children’s block-building complexity and have implications for classroom instructions aimed at improving preschoolers’ block-building complexity.

Novel Biomass Derived from Grape Pomace Waste as an Efficient Nanocatalyst for the Synthesis of Dibenzoxanthene, Tetraketone, bis(indolyl)alkane and Chromene Derivatives and their Antimicrobial Evaluation.

Sulfonated carbon-based solid acids (CBSAs) have been reported as an efficient solid acid catalyst for many acid-catalyzed reactions. Furthermore, the use of carbon obtained from biomass waste has been explored and these materials showed a higher catalytic performance and higher stability compared to other solid acids. Novel biomass carbon-based solid acids nanoparticles with high catalytic activity in organic transformation, such as Grape pomace waste-SO3H Nanoparticles (GPW-SO3H NPs), were successfully synthesized. Grape pomace waste-SO3H Nanoparticles (GPW-SO3H NPs) were successfully synthesized. The grape pomace waste was dried in an oven at a temperature of 70°C and crushed to powder using an electric spice grinder. A mixture of powdered grape pomace waste (1 g) and concentrated sulfuric acid (>98%, 10 mL) was stirred at room temperature. Then, the resultant mixture was transferred into a 100 mL sealed Teflon-lined autoclave and kept at 180°C for 12 h. After cooling to room temperature, the resulting black solid was dried at 100°C in an oven under vacuum and the sulfonic acid-functionalized magnetic nanoparticles (Fe3O4@C-SO3H) were obtained. The catalytic activity of GPW-SO3H was assessed through an easy and rapid protocol developed for the one-pot synthesis of 14-aryl-14-H-dibenzo [a,j]xanthene, arylmethylene [bis(3- hydroxy-2-cyclohexene-1-one)], bis(indolyl)alkane and 2-amino-4-aryl-7-hydroxy-4H-chromene-3-carbonitrile derivatives in excellent yields. The advantages of this method include use of waste material for catalyst synthesis, high yields, mild reaction conditions, uncomplicated work-up procedures, neutral conditions, and recoverable catalyst. We have shown that biomass-derived solid acids, prepared from grape pomace waste, serve as a non-toxic, inexpensive and a promising eco-friendly and novel carbon-based solid acid nanocatalyst for organic transformations.

A New waste-free integrated approach for sapropel processing using supercritical fluid extraction

An integrated approach to the processing of sapropel with the use of supercritical CO2 extraction of bioactive substances with carbon dioxide at the first step of the process is discussed. The dependences of the yield and composition of extracts (8−35 MPa, 50 °C) and features of sapropel are established. Further carbonization of the solid residue remaining after extraction results in organic-rich products (phenol and its mono, dialkyl and methoxy derivatives, hydrocarbons C14-C22) and carbon-mineral materials with a total pore volume of 0.681–1.211 cm3 g−1. It was found that the introduction of the initial stage of treatment with supercritical CO2 allows not only extracting valuable amino acids, but also affects the yield, composition and properties of liquid and solid sapropel transformation products at subsequent stages of heat treatment.

Effect of Polymers and Storage Relative Humidity on Amorphous Rebamipide and Its Solid Dispersion Transformation: Multiple Spectra Chemometrics of Powder X-Ray Diffraction and Near-Infrared Spectroscopy.

This study aimed to investigate the effect of polymers and storage relative humidity on amorphous rebamipide (RB) and its solid dispersion phase transformation using chemometrics based on multiple datasets. The amorphous RB was prepared using particle mixture and grinding methods with hydroxypropyl cellulose, polyvinylpyrrolidone, and sodium dodecyl sulfate. Prepared amorphous RB and solid dispersion samples were stored under a relative humidity of 30% and 75% for four weeks. Infrared spectra of the dispersion samples suggested that the hydrogen bond network was constructed among quinolinone, carbonyl acid, and amide of RB and other polymers. The dataset combining near-infrared (NIR) spectra and powder X-ray diffractograms were applied to principal component analysis (PCA). The relationship between diffractograms and NIR spectra was evaluated using loadings and the PCA score. The multiple spectra analysis is useful for evaluating model amorphous active pharmaceutical ingredients without a standard sample.

Design and Control a High Gain Synchronous Buck Converter for a Solid State Distribution Transformer

A Conventional distribution transformer consists of bulky windings, cores and coolant liquid hence it is weighty and large in size. Now days, supporting by development of power semiconductor devices, the idea to develop distribution transformers using switching power converter technology becomes viable. This paper proposed a new structure of a solid state transformer (SST) for power electrical distribution system. The proposed SST works without utilizes high frequency isolating transformer. Instead, high gain cascaded Buck converters are used. The design of Buck Converters involves calculation of the applied components such as Inductors and Capacitors. Simulation result verifies that Buck Converters work well to reduce DC voltage of 25 kV DC voltage to 620 V DC without excessive ripple. The proposed SST is successfully operated to step down 20 KV of AC voltage to 400 V with THD of output voltage less than 2 %.

Crystal forms and phase transformation of 1,5-pentanediamine-terephthalate: a bio-based nylon 5T monomer.

Nylon 5T is one of the bio-based nylons, its raw material 1,5-pentanediamine is derived from biomass resources and produced by biological methods. 1,5-pentanediamine-terephthalate (PDA-TPA) is the monomeric salt for nylon 5T polymerization, and its own product quality has a significant impact on the performance of nylon 5T. PDA-TPA was prepared by anti-solvent crystallization in this study. It exists in two solid forms, a monohydrate [form (I)] and an anhydrous phase [form (II)]. The transition temperature of the two phases was around 65°C in the given ethanol-water binary (7:1) mixture. The characterization of monohydrate and anhydrate phases regarding structures and stabilities was carefully carried out using powder X-ray diffraction, single crystal X-ray diffraction, differential scanning calorimetry, thermogravimetric analysis, hot-stage microscopy and Fourier transform infrared spectroscopy. The relationship between the molecular interactions of monohydrate and anhydrate phases under different packing architectures and their thermal behaviours was analysed and established. In addition, the relationships between the structures and thermal behaviours for the two solid forms were analysed and established. In addition, the effect of solvent on phase conversion, the relationships between the temperature and water activity, as well as the relative stability of monohydrate and anhydrate phases under different thermodynamic conditions, were investigated by solid-solid transformation and solvent-mediated transformation experiments. It was obvious that the transition temperature of monohydrate and anhydrate phases of PDA-TPA was significantly influenced by water activity, and the larger the value of water activity is, the higher is the transition temperature. These studies give insight into the transformation of nylon 5T monomer salt and contribute to the control of target crystal preparation.

Magnetic-Field-Induced Liquid–Solid Interface Transformation and Its Effect on Microsegregation in Directionally Solidified Ni-Cr Alloy

The transformation of liquid–solid interface induced by the steady magnetic field (SMF) in the directionally solidified Ni-10 wt pct Cr alloy was studied experimentally. At the moderate pulling rate (50 μm s−1), it could be observed that the interface morphology gradually transformed from planar to cellular shape with increasing the SMF intensity (0 T, 3 T, 6 T). However, the cellular interface at the high pulling rate (100 μm s−1) was not influenced by the SMF. 3D numerical simulations suggested that the transformation of interface morphology originated from the thermoelectric magnetic convection near the wavelike interface at the early stage of solidification. From the composition measurement, it was found that the formation of microsegregation at the moderate pulling rate was associated with the interface morphology. Under the 3 T SMF, the liquid–solid interface remained planar and the microsegregation level increased in comparison with that without the SMF. Under the 6 T SMF, the liquid–solid interface became cellular and the microsegregation level was reduced. The factors affecting microsegregation were evaluated. The effective partition coefficient was estimated based on composition data. It was revealed that the effective partition coefficient increased with the 6 T SMF due to the thermoelectric magnetic and magnetic damping effects within the cellular structure. Additionally, the solid diffusivity was measured using the diffusion couple technique. It was found that the interdiffusion coefficient of Cr decreased with increasing the SMF intensity. The modified Brody model was used to predict the microsegregation behavior in the SMF. The predicted results were in agreement with experimental observation. It could be concluded that the decrease in solid diffusivity enhanced the formation of microsegregation for the planar interface, whereas the increase in effective partition coefficient in the SMF was beneficial for alleviating the extent of microsegregation for the cellular interface.

Evolution of cellular morphology in pure materials

The evolution of cellular morphology during interfacial instability for liquid–solid transition for pure unary material systems is studied using the maximum entropy production (generation) rate principle (MEPR) for steady-state directional solidification. This approach is dependent on a quantity called maximum entropy production rate density which inherently contains key solidification parameters that governs cellular evolution for liquid–solid transformation. The maximum entropy production rate density is computationally measured from the solid–liquid interface in diffuse form and considers steady-state solidification at low velocities for both near and far from equilibrium conditions. The results are presented in mathematical expressions for morphological instability that corresponding to the evolution of a cellular morphology which emanates from the solid–liquid interface. The model is formulated to evaluate the solid–liquid interface thickness, the solidification velocity, grain boundary energy, and the size of the cellular morphological at instability. The results are tested with a number of pure single element materials at different temperature gradients which compare well with available experimental data.

Clinical characteristics and CT imaging features of patients with different clinical types of coronavirus disease 2019

To investigate the clinical characteristics and CT imaging features of patients with different clinical types of coronavirus disease 2019 (COVID-19), so as to provide a reference for the treatment and evaluation of COVID-19. The clinical data of 278 patients with COVID-19 admitted to Guangzhou Eighth People's Hospital from January 20th to February 10th in 2020 were collected. The patients were divided into mild, ordinary, severe and critical types. The differences of clinical symptoms and signs, laboratory examination indexes and CT image features of lung in different clinical types were analyzed and compared, and the relationship between clinical and imaging features and clinical types of diseases were analyzed. Among the 278 patients with COVID-19, 130 were male (46.8%) and 148 were female (53.2%), of whom 88.8% (247/278) were 20 to 69 years old. 238 (85.6%) patients combined one or more basic diseases. The source of cases was mainly imported cases (n = 201, 72.3%), of whom 89 cases were imported from Wuhan, accounting for 44.3% of all imported cases. With the aggravation of the disease, the male composition ratio, age and the number of basic diseases of patients gradually increased, and the incidences of fever, dry cough, chilly or chills, and fatigue in severe and critical patients were significantly higher than those in the mild and ordinary ones. The white blood cell count (WBC), neutrophil counts (NEU) and proportions (NEU%) of the severe and critical patients were higher than those of the mild and ordinary patients [WBC (×109/L): 5.7±3.1, 6.5±2.4 vs. 5.4±1.7, 4.9±1.6; NEU (×109/L): 4.4±3.1, 4.9±2.5 vs. 2.8±1.2, 2.9±1.3; NEU%: 0.72±0.13, 0.73±0.14 vs. 0.51±0.12, 0.59±0.11; all P < 0.01], while the lymphocyte count (LYM) and ratio (LYM%), platelet count (PLT) were lower than those in the mild and ordinary patients [LYM (×109/L): 1.0±0.4, 1.2±0.8 vs. 2.1±0.9, 1.5±0.6; LYM%: 0.21±0.11, 0.20±0.12 vs. 0.40±0.11, 0.32±0.11; PLT (×109/L): 177.1±47.8, 157.7±51.6 vs. 215.3±59.7, 191.8±64.3; all P < 0.05]. The level of albumin (Alb) was the lowest in the critical patients and the level of total bilirubin (TBil) was the highest, which was statistically significant as compared with the mild, ordinary and severe patients [Alb (g/L): 33.0±5.8 vs. 42.8±4.4, 39.6±5.1, 34.4±4.2; TBil (μmol/L): 20.1±12.8 vs. 12.0±8.7, 10.9±6.3, 12.2±8.3; both P < 0.01]. Lactate dehydration (LDH) and cardiac troponin I (cTnI) in the severe and critical patients were significantly higher than those in the mild and ordinary patients [LDH (μmol×s-1×L-1): 5.6±2.2, 5.0±2.9 vs. 2.8±0.9, 3.3±1.2; cTnI (μg/L): 0.010 (0.006, 0.012), 0.010 (0.006, 0.012) vs. 0.005 (0.003, 0.006), 0.005 (0.001, 0.008); both P < 0.05]. C-reactive protein (CRP) level of severe patients were higher than that in the mild, ordinary and critical patients [mg/L: 43.3 (33.2, 72.1) vs. 22.1 (16.2, 25.7), 29.7 (19.8, 43.1), 25.8 (23.0, 36.7), P < 0.01]. The level of procalcitonin (PCT) in the severe and critical patients was higher than that in the mild and ordinary patients [μg/L: 0.17 (0.12, 0.26), 0.13 (0.09, 0.24) vs. 0.06 (0.05, 0.08), 0.05 (0.04, 0.09), P < 0.01]. The typical CT imaging features were as follows: the ordinary type mainly showed the single or multiple ground glass shadows on the chest image; the severe type mainly showed the multiple ground glass shadows, infiltration shadows or solid transformation shadows. Compared with the ordinary patients, the lesions increase, and the scope of the lesion expanded to show double lungs. Critical type was mainly manifested as diffuse consolidation of both lungs with multiple patchy density increase shadows, multiple leafy patchy density increase shadows were seen on each leaf, most of them were ground glass-like density, and some were shown separately lung consolidation. Men, advanced aged, and combining multiple underlying diseases are high-risk populations of COVID-19, and they should pay close attention to the risk of progressing to severe or critical type. CT imaging features could be used as an important supplement when diagnosing severe and critical COVID-19.

Exploring the solid-state phases and thermodynamics of calcium l-lactate

Calcium l-lactate, an organic salt derived from l-lactic acid, is used in many fields such as food, pharmaceutical or cosmetic industry. To this date, its solid-state thermodynamics are still poorly understood: a pentahydrate crystalline and anhydrate amorphous forms were already characterized, and potential other hydrates mentioned in literature. For the development of a robust crystallization process or down-line handling of this compound, it is important to know and understand the relationship between the different solid forms to prevent uncontrolled crystallization or solid–solid transformation during storage. In this paper, we aimed at identifying and characterizing novel solid forms of calcium l-lactate. Combining analytical techniques, we confirmed the existence of the pentahydrate and an amorphous anhydrate. In addition, we played on temperature and relative humidity conditions to discover three new crystalline forms (a crystalline anhydrate, monohydrate and dihydrate). This paper is the first occasion where these forms were successfully isolated and characterized.

A closer look at superionic phase transition in (NH4)4H2(SeO4)3: impedance spectroscopy under pressure.

The proton-conducting material (NH4)4H2(SeO4)3 is examined to check whether its conductivity spectra are sensitive to subtle changes in the crystal structure and proton dynamics caused by external pressure. The AC conductivity was measured using impedance spectroscopy, in the frequency range from 100 Hz to 1 MHz, at temperatures 260 K < T < 400 K and pressures 0.1 MPa < p < 500 MPa. On the basis of the impedance spectra, carefully analyzed at different thermodynamic conditions, the p-T phase diagram of the crystal is constructed. It is found to be linear in the pressure range of the experiment, with the pressure coefficient value dTs/dp = -0.023 K MPa-1. The hydrostatic pressure effect on proton conductivity is also presented and discussed. Measurements of the electrical conductivity versus time were performed at a selected temperature T = 352.3 K and at pressures 0.1 MPa < p < 360 MPa. At fixed thermodynamic conditions (p = 302 MPa, T = 352.3 K), the sluggish solid-solid transformation from low conducting to superionic phase was induced. It is established that the kinetics of this transformation can be described by the Avrami model with an effective Avrami index value of about 4, which corresponds to the classical value associated with the homogeneous nucleation and three-dimensional growth of a new phase.

Comments on “Measurement and correlation of the solubility of estradiol and estradiol-urea co-crystal in fourteen pure solvents at temperatures from 273.15 K to 318.15 K”

The reported study by Ning et al. about measurement and correlation of the solubility of estradiol and estradiol-urea co-crystal in fourteen pure solvents at temperatures from 273.15 K to 318.15 K has been evaluated from viewpoint of the applied method for determination of co-crystal solubility; and the effect of solid transformations in determination of co-crystal solubility has been discussed.

An automated predictor for identifying transition states in solids

The minimum energy path (MEP) and transition state are two key parameters in the investigation of the mechanisms of chemical reactions and structural phase transformations. However, determination of transition paths in solids is challenging. Here, we present an evolutionary method to search for the lowest energy path and the transition state for pressure-induced structural transformations in solids without any user input or prior knowledge of possible paths. Instead, the initial paths are chosen stochastically by connecting randomly selected atoms from the initial to final structure. The MEP of these trials paths were computed and ranked in order of their energies. The matrix particle swarm optimization algorithm is then used to generate improved transition paths. The procedure is repeated until the lowest energy MEP is found. This method is validated by reproducing results of several known systems. The new method also successfully located the MEP for the direct low-temperature pressure induced transformation of face centered-cubic (FCC) silicon to the simple hexagonal(sh) phase and FCC lithium to a complex body centered-cubic cI16 high-pressure phase. The proposed method provides a convenient, robust, and reliable approach to identify the MEP of phase transformations. The method is general and applicable to a variety of problems requiring the location of the transition state.

Structural similarity and similarity in thermal properties of the polymorphs: melting and crystallization from the melt of tolbutamide and chlorpropamide

The polymorphism of tolbutamide and chlorpropamide under melting/crystallization was investigated with using DSC and in situ X-ray powder diffraction. The asymmetry in thermal transformations was revealed for both substances. Under heating, all tolbutamide/chlorpropamide polymorphs transform into high-temperature IH/e polymorph, which melts at 128 °C. The crystal structures of the high-temperature polymorphs, IH and e, are very similar to each other in the unit cell parameters and in the arrangement of z-shaped infinite hydrogen-bonded ribbons. Under cooling, other polymorph crystallizes from the melt, V for tolbutamide and β for chlorpropamide, thus making easy the obtaining of these metastable polymorphs. The polymorphs of tolbutamide and chlorpropamide crystallized from their melts turned out to be also very similar to each other in their structures (space group, unit cell parameters, arrangement of π-shaped infinite hydrogen-bonded ribbons). Solid–solid transformation V ⇒ II in tolbutamide was detected both in samples stored under room conditions and those melted in capillaries, thus providing new easy way for II tolbutamide crystallization. In generalizing our results, one can expect that if evident similarity is found among the polymorphs of similar molecules in their crystal structure, the similarity in their thermal properties can be also found, and vice versa.

Fast Evaluation of Two-Center Integrals over Gaussian Charge Distributions and Gaussian Orbitals with General Interaction Kernels.

We present efficient algorithms for computing two-center integrals and integral derivatives, with general interaction kernels K(r12), over Gaussian charge distributions of general angular momenta l. While formulated in terms of traditional ab initio integration techniques, full derivations and required secondary information, as well as a reference implementation, are provided to make the content accessible to other fields. Concretely, the presented algorithms are based on an adaption of the McMurchie-Davidson Recurrence Relation (MDRR) combined with analytical properties of the solid harmonic transformation; this obviates all intermediate recurrences except the adapted MDRR itself, and allows it to be applied to fully contracted auxiliary kernel integrals. The technique is particularly well-suited for semiempirical molecular orbital methods, where it can serve as a more general and efficient replacement of Slater-Koster tables, and for first-principles quantum chemistry methods employing density fitting. But the formalism's high efficiency and ability of handling general interaction kernels K(r12) and multipolar Gaussian charge distributions may also be of interest for modeling electrostatic interactions and short-range exchange and charge penetration effects in classical force fields and model potentials. With the presented technique, a 4894 × 4894 univ-JKFIT Coulomb matrix JAB = (A|1/r12|B) (183 MiB) can be computed in 50 ms on a Q2'2018 notebook CPU, without any screening or approximations.

The Misfit Strain Energy Collapse during Precipitation in Solid Transformations

The misfit strain energy collapse (MSEC) which results in the dendritic or split γ’ precipitating particles during solid transformations in Ni-base alloys is discovered. Three parameters of the MSEC function, the MSEC delay, the MSEC rate, and the initial value of the MSEC function, are correlated to the persistence of the isothermal cooling, the rate during the continuous cooling, and the initial misfit strain during nucleation respectively. The MSEC point is the intersection of the two crystal lattice parameters \U0001d44e\U0001d6fe’(T) and \U0001d44e\U0001d6fe(T) of the two different phases.

Exploring the Complexity of Processing-Induced Dehydration during Hot Melt Extrusion Using In-Line Raman Spectroscopy

The specific aim in this study was to understand the effect of critical process parameters on the solid form composition of model drug compounds during hot melt extrusion using in-line Raman spectroscopy combined with Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) modeling for semi-quantitative kinetic profiling. It was observed that the hydrate and anhydrate solid forms of two model drugs in the melts of nitrofurantoin (NF):polyethylene oxide (PEO) and piroxicam (PRX):PEO could be resolved from a MCR-ALS model without an external calibration dataset. Based on this model, the influence of two critical process parameters (shear and temperature) on the solid form composition could be evaluated in a real-time mode and the kinetics of complex transformation pathways could be explored. Additionally, the dehydration pathways of NF monohydrate and PRX monohydrate in molten PEO could be derived. It can be concluded that dehydration of both hydrates in PEO occurs via competing mechanisms—a solution-mediated transformation pathway and a solid–solid transformation, and that the balance between these mechanisms is determined by the combined effect of both temperature and shear. Another important observation was that the water released from these hydrate compounds has a detectable effect on the rheological characteristics of this mixture.

Reversible, Two-Step Single-Crystal to Single-Crystal Phase Transitions between Desloratadine Forms I, II, and III

Single-crystal to single-crystal polymorphic transformations in molecular solids are relatively rare, with changes in crystal structure more commonly leading to destruction of the parent crystal. H...

Synthesis of regularly shaped AlPO4-11 molecular sieve through a solid transformation approach

Abstract The development of efficient synthesis route is the main topic in practical applications and fundamental issues of molecular sieves. In this work, a new route for direct synthesis of regularly shaped aluminophosphate molecular sieve (AlPO4-11-S) is reported. The obtained molecular sieve is fully crystallized and show excellent physicochemical properties such as hierarchically porosity and high mechanical strength which meet the request for direct applications in industry. The key intermediates in the crystallization have been carefully investigated, from which the new insights into the molecular sieve formation mechanism are proposed. The water and n-DPA molecules well retained by ionic liquids in the initial dry extrudates play an important role in the formation of regularly shaped molecular sieve. This route shows great potentials in the industrial applications considering the features such as fewer synthesis steps, rapid crystallization, and obtaining materials with high content of molecular sieve, regularly shaped form, high mechanical strength and hierarchical pores.