Study of sauce glazed wares from Yaozhou kilns (Northern Song Dynasty, 960–1127 CE): Probing the morphology and structure of crystals in the glazes

Sauce glaze is one of the main varieties of glazes produced in the Yaozhou kilns during the Song Dynasty. It is famous for its reddish-brown color and high gloss. In this work, the elemental composition, morphology, structure, and light reflectivity of glazes of archeological sherds were systematically studied. A large number of ε-Fe₂O₃ dendritic crystals were observed in the glazes. Alkali etching was implemented to remove the glassy matrix surrounding these crystals to further investigate their microstructure. SEM observations emphasize that they are composed of well-arranged parallel branches separated by about 230 nm, each of which consisting of offset stacks of many small flake-shaped crystals, with the offset ranging from 100 to 110 nm. Based on these results, the origin of the reddish-brown color and high gloss was discussed. In addition, cordierite crystals were observed for the first time in the sauce glaze from Yaozhou kilns.     

Composition comparison of Zhejiang Longquan celadon and its imitation in Dapu kiln of Guangdong in the Ming Dynasty of China (1368–1644 CE) by LA-ICP-MS

Identification of Longquan celadon and its imitation is more and more caught the attention of experts in different fields. In this paper, by using laser ablation- inductively coupled plasma mass spectrometry (LA-ICP-MS) and other analytical methods, body and glaze of samples from Zhejiang Longquan celadon and its imitation in Dapu kiln of Guangdong in the Ming Dynasty of China were determined. Our research reveals that (1) the celadon bodies from the Dapu kiln contain less Al₂O₃, Mo, V, Cr and Ni, and more SiO₂ content than those of the Longquan kiln; (2) the celadon glazes from both the Longquan and Dapu kilns show higher content of CaO, Al₂O₃, Ba, Sr, P₂O₅ and MnO than the corresponding bodies; and (3) both the celadon bodies and glazes from the Dapu kiln have higher ΣREE and in particular significantly negative Ce anomalies, distinctly different from those from Longquan kiln. These results would not only provide a good basis to identify the Longquan celadon and its imitation, and even to protract the global trade route in ancient time, but also be beneficial to better understanding the recovery and transmission of Longquan celadon manufacturing technology.     

Understanding the adsorption behavior of oxygen on the 3C–SiC(1 1 0) surface: A first-principles study

The adsorption behavior of atomic oxygen and molecular O₂ on the 3C–SiC(1 1 0) surface is investigated by first-principles calculations. The atomic O prefers to be adsorbed at the C top site (C–O) with adsorption energy of −1.95 eV after zero-point energy correction, followed by the C–O–Si bridge site, Si–O–Si bridge site, and the Si top site (Si–O) with adsorption energies of −1.46, −1.36, and −1.13 eV, respectively. The molecular O₂ separately trapped by the second nearest neighboring C and Si atoms (C–O–O–Si, M4 type) is the most stable configuration with the adsorption energy of −2.46 eV, which is followed by the Si–O–O–Si (M5 type), C–O–O–Si (M3 type), O–Si–O (M2 type), and Si–O=O (M1 type) configurations with the adsorption energies of −2.24, −1.87, −1.07, and −0.75 eV, respectively. All these molecular O₂ adsorption configurations exhibit high tendency to dissociate with the dissociation barriers range of 0.09–0.19 eV. The adsorbed atomic O seems to be easily trapped at the C–O site due to the extremely low diffusion barrier. In addition, the infrared spectra of all the atomic O and molecular O₂ adsorption configurations are predicted and compared with available experimental observations.     

A study on the recovery of actinide elements from molten LiCl–KCl eutectic salt by an electrochemical separation

Pyroprocessing is a prominent way for the recovery of the long-lived elements from the spent nuclear fuel. Electrorefining is a key technology for pyroprocessing and generally composed of two recovery steps—deposition of uranium onto a solid cathode and the recovery of TRU (TRansUranic) elements. In this study, it was investigated on electrochemical separation of actinides to develop an actinide recovery system in a molten LiCl–KCl eutectic salt. In the electrorefining experiment, uranium was successfully separated from cerium. The effects of the anode material and the surface area were investigated during the electrolysis experiments for a more efficient electrorefining system. Anode potential decreased with an increasing anode surface area, however, an anode effect was observed in case of a complicated anode structure for high surface area. Glassy carbon was found to be the best anode material among the molybdenum, graphite, glassy carbon, and oxide materials. It was found that the solid cathode with a perforated ceramic container could be one of the candidates for a salt clean-up process to remove residual actinide elements in the salt after the recovery step.     

Comparative microstructural study of celadon excavated from Housi’ ao kiln site in China (Late Tang and Five Dynasties): Mi-se porcelain and ordinary Yue celadon

Mi-se porcelain provided a step change in the history of Chinese porcelain making and influenced kiln production of later generations as well as the aesthetic orientation of society. This work compares the microstructure of ordinary Yue celadon and Mi-se porcelain. The Mi-se porcelain glaze was found to be simpler and more uniform than ordinary Yue celadon, with only some bubbles existing in the glaze. Compared with ordinary Yue celadon, the residual quartz and pores in the Mi-se porcelain body were smaller. Mi-se porcelain production is more standardized than ordinary Yue celadon. The presence of calcium phosphate in the glaze indicates that grass wood ash was used in the Yue kiln. Our research confirms that Mi-se porcelain was not the best porcelain as selected from the Yue kiln products, but it is a type of celadon that was specially fired using fine raw material processing and certain firing techniques.     

The deactivation study of Co–Ru–Zr catalyst depending on supports in the dry reforming of carbon dioxide

Carbon dioxide reforming of methane was performed over Co–Ru–Zr catalyst (0.4 wt% Ru added, calcined at 400 °C) with different supports (SiO₂, γ-Al₂O₃ and MgO) in order to study their deactivation. The Co–Ru–Zr/γ-Al₂O₃ showed the highest activity at first, but severe deactivation was observed due to carbon deposition. Co–Ru–Zr/MgO exhibited low activity because of its low specific surface area. However, the high conversions could be obtained in Co–Ru–Zr/SiO₂, and activity was kept almost constantly for 500 h reaction. The characteristics of the catalysts, before and after the reaction, were investigated employing BET, XRD, TPR, TGA-DTA and TEM.     

Study of the Effect of Fluorine Atom(s) on Fluoromethylated Imines in the Tandem Mannich–Michael-type Reaction

Differences in chemical behavior between non-fluorinated and fluorinated methylimines in the tandem Mannich–Michael-type reaction are described based on NMR and computational studies.     

Using laser ablation inductively coupled plasma mass spectroscopy (LA-ICP-MS) to determine the provenance of the cobalt pigment of Qinghua porcelain from Jingdezhen in Yuan Dynasty of China (1271–1368AD)

The provenance of cobalt mineral of the blue decoration in Yuan Qinghua porcelain would reveal the technological and cultural interaction between ancient China and the Islamic world. However, the limitation of conventional methods in the determining trace elements of the blue decoration hampered the deep research on provenance of the cobalt mineral. In the paper, we employed the good advantage of Laser-ablation-inductively-coupled-plasma-mass-spectroscopy (LA-ICP-MS) to determine the major element and trace elements of blue decoration of the different type of Qinghua successfully. The blue decoration of all different types of samples shared the same characteristics of higher FeO and lower Mn, which suggested the potter adopted the non-native cobalt material of China to paint the Yuan Qinghua in Jingdezheng, and the difference on the outside appearance of blue decoration of different samples were supposed to be related to the tenor of ore, the different treatment process of cobalt material and the firing process in the kiln. In addition, the significant differences on the element concentrations of Cu, Ni, Pb, Zr and Sb in the blue decoration between Yuan Qinghua and the Islamic blue and white wares of 13–14th century provided a new evidence to discuss the provenance of the cobalt of Yuan Qinghua porcelain.     

Preferred partitioning: the influence of coalescents on the build-up of mechanical properties in acrylic core–shell particles (I)

The partitioning of three coalescents of different polarity in different phases of multiphase acrylic particles was studied to provide a rationale for obtaining the desired performance of binders for wood coatings in terms of the ideal balance between hardness development, blocking resistance, and blushing resistance. Minimum film formation temperature- and aqueous differential scanning calorimetry-measurements on the hard phase polymer by itself showed the different extents to which both hydroplasticization and plasticization by the coalescent occur. Dynamic mechanical thermal analysis was subsequently used to visualize wet-T _g effects of three different coalescents in the hard and soft polymer phase of these multiphase acrylic particles. The results have important consequences for the formulation of such binders in applications for exterior wood coatings and coatings in general.     

A study on the crystallization behavior of poly(β-hydroxybutyrate) thin films on Si wafers

The exact molecular chain orientation of poly(β-hydroxybutyrate) (PHB) in ultrathin films was successfully probed using surface-sensitive, grazing incidence X-ray diffraction techniques. The crystal orientation of spin-coated PHB films was very sensitive to free surface and thermal annealing. In pristine films, the free surface easily exerted its influence on PHB crystallization and caused lamellar orientation with the b-axis perpendicular to the film surface. The effect of the buried interface increased with temperature. With the increase in thermal annealing temperature, the lamellar orientation changed from the b-axis being perpendicular to the film surface to the c-axis becoming perpendicular to the film surface. As film thickness increased, the temperature, at which the lamellae with the b-axes oriented normal to the film surface disappeared, increased. The thickness and temperature dependence of the crystallization behavior of PHB in an ultrathin film could be attributed to the competition between the effects of the free surface and the buried interface.     

Effect of porosity on the microhardness testing of brittle ceramics: A case study on the system of NiO–ZrO2

Microhardness tests were conducted on a series of NiO–ZrO₂ ceramics with different porosities ranging from 2% to 18%. For each sample, the measured hardness decreases with increasing indentation load, showing a significant indentation size effect. The indentation data were analyzed according to the modified proportional specimen resistance (PSR) model and it was found that the resultant load-independent hardness decreases with increasing porosity. The porosity-dependence of the load-independent hardness was analyzed and a concept of true hardness was proposed to characterize the actual material resistance to indentation-induced plastic deformation. Furthermore, the applicability of the modified PSR model in describing the indentation size effect observed on porous materials is discussed.     

Role of porosity on the stiffness and stability of (001) surface of the nanogranular C–S–H gel

We present here a nanoscale modeling of the bulk and surface states of the nanogranular Calcium Silicate Hydrate (C–S–H) gel. Regarding the mechanical properties as well as porosity, we identify two main phases: a ductile one, for a porosity from 12.4% to 27% and a brittle phase for a porosity lower than 12.4% or higher than 27%. Particularly, our calculations show that 20% of gel porosity gives a better structural stability to C–S–H and a higher stiffness. Besides, we have explored the (001) surface of C–S–H gel at the nanoscale level and have proved that more water on the surface will stabilize thermodynamically the nanostructure. This means that adsorbed H₂O molecules lead to the coexistence of Si–OH and Ca–OH groups on the surface. The calcium-terminated plane is a polar and unstable surface, and will either reconstruct to neutralize the dipole moment or adsorb ions to remove it. Our results also show that the (001) surface of low density C–S–H tends to be more stable than the surface of high density phase since the obtained surface energy decreases with increasing gel porosity.     

Synthesis of cubic zirconium(IV) nitride,c-Zr3N4, in the 6–8 GPa pressure region

We report on the lowermost pressure and temperature conditions where cubic zirconium(IV) nitride having Th₃P₄-type structure, c-Zr₃N₄, forms in a belt-type apparatus. This novel hard material having exceptional wear resistance by machining of low-carbon steels appears at pressures between 6.5 and 7.7 GPa when heated to 1400–1600 °C. Single-phase samples were obtained at P = 7.7 GPa thus indicating that the industrial scale synthesis of this innovative material is feasible. Chemical reaction of the sample material with the Pt-capsule led to formation of a Pt–Zr alloy, as a minor admixture, which can potentially be used as a binder for cementing of polycrystalline c-Zr₃N₄ tools.     

Effect of Polysaccharides on the Properties of the Mucoadhesive Poly(Vinyl Alcohol) Multicore–Shell Microparticles

This study discusses about the effect of polysaccharides (agar, gum tragacanth, and guar gum) on the properties of the core (organogel)–shell [poly(vinyl alcohol)] microparticles. The size, swelling, and mucoadhesive properties of the poly(vinyl alcohol) microparticles were altered in the presence of the polysaccharides. Thermal analysis confirmed the presence of organogels within the microparticles. Fourier transform infrared spectroscopy confirmed the presence of the polysaccharides within the microparticles. The microparticles were biocompatible in nature. Drug release indicated that an alteration in the shell composition can be used for altering drug release. Ciprofloxacin-loaded microparticles showed sufficient antimicrobial efficiency.     

Influence of the availability of calcium on the hydration of tricalcium aluminate (C3A) in seawater-mixed C3A–gypsum system

This work examined the effects of seawater (SW) on the hydration of tricalcium aluminate (C₃A) in C₃A–gypsum and C₃A–gypsum–Ca(OH)₂ systems through the characterization of hydration heat release, the evolution of aqueous phase composition and hydration products with the hydration time. It was found that SW increased the dissolution driving force of C₃A and solubility of gypsum, which accelerated the early hydration of C₃A and the formation of ettringite (AFt), leading to a higher hydration degree of C₃A at an early age compared with the deionized (DI) water–mixed pastes. After gypsum depletion to form AFt, and in the absence of Ca(OH)₂, the formation of chloroaluminate hydrates was slower due to the insufficient Ca resulted in an accumulation of Al in solution. This would delay the subsequent transformation of AFt to monosulfate (SO₄–AFm) and the formation of hydrogarnet (C₃AH₆), which would further reduce the hydration degree of the C₃A at the later ages. However, in the presence of Ca(OH)₂, the hydration degree of C₃A–gypsum–Ca(OH)₂ at later ages was increased, which was similar to that of the corresponding DI pastes. This can be inferred that the amount of Ca available in SW-mixed cement concrete can affect the hydration degree of C₃A in cement.     

Effect of the acid–base composition of water on the wettability of coals of different ranks (Short Communication)

The results of the experimental studies allowed us to assume that the process characteristics determined by the wettability of coal (dust suppression, hydraulic fracturing, coal washing, etc.) may be insensitive to the acid–base composition of utilized water in a range of pH 4.6–10.     

Hydrogenation of (–)-Carvone in Presence of Gold Catalysts: Role of the Support

The liquid phase hydrogenation of biomass derived (–)-carvone into industrially valuable dihydrocarvone was studied over monometallic Au catalysts supported on alumina, titania and zirconia, as well as on the mesoporous carbon support Sibunit in methanol as a solvent (100°C, hydrogen pressure 9 bar). It was shown that among the three types of functional groups present in carvone, which can be hydrogenated, namely C=O, conjugated and isolated C=C groups, hydrogenation of the latter was predominant. The catalytic activity was found to depend on the catalyst support type. Under comparative reaction conditions, the carvone conversion increased in the following sequence: Au/C ?Au/ZrO₂ < Au/Al₂O₃ ?Au/TiO₂. A higher activity of Au catalysts over metal oxides as compared to Au/C can be caused by the presence of acid sites as well as oxygen vacancies in their structure allowing strong adsorption of carvone through its carbonyl moiety. All catalysts supported on oxides showed similar selectivity towards trans- and cis-dihydrocarvone with the ratio between isomers (trans-/cis-isomer) being about 1.8, while this value for Au/C was close to 3.9, which can be related to a much lower carvone conversion in the latter case.     

Sintering of powders in the CrSi2–Ti(Ta)Si2 systems depending on the methods for synthesis

Composite materials based on refractory silicides, in particular their solid solutions, are widely used in many areas of engineering for parts of heating elements and heat resistance protective coatings. This paper presents the findings obtained in the study of peculiarities of solid-phase interaction during synthesis of Cr_0.9Ta_0.1Si₂ and Cr_0.5Ti_0.5Si₂ solid solutions depending on the synthesis conditions. The effect of the powder dispersity on compaction of targets from Cr_0.9Ta_0.1Si₂ and Cr_0.5Ti_0.5Si₂ powders has been studied, and it has been established that the use of nanosized powders complicates the process of pressing. Also, sintering of targets from nanosized Cr_0.9Ta_0.1Si₂ and Cr_0.5Ti_0.5Si₂ powders was studied. The sintered targets were established to have a small grain size and uniform porosity all over the volume. Thanks to small closed porosity, the targets exhibit high heat resistance under thermal shock.