Silicon-Boron Alloys as New Ultra-High Temperature Phase-Change Materials: Solid/Liquid State Interaction with the h-BN Composite

Silicon-boron alloys have been recently pointed out as novel ultra-high temperature phase change materials for applications in Latent Heat Thermal Energy S     

Ascorbic Acid Supplementation Improves Skeletal Muscle Growth in Pacu (Piaractus mesopotamicus) Juveniles: In Vivo and In Vitro Studies

In fish, fasting leads to loss of muscle mass. This condition triggers oxidative stress, and therefore, antioxidants can be an alternative to muscle recovery. We investigated the effects of antioxidant ascorbic acid (AA) on the morphology, antioxidant enzyme activity, and gene expression in the skeletal muscle of pacu (Piaractus mesopotamicus) following fasting, using in vitro and in vivo strategies. Isolated muscle cells of the pacu were subjected to 72 h of nutrient restriction, followed by 24 h of incubation with nutrients or nutrients and AA (200 µM). Fish were fasted for 15 days, followed by 6 h and 15 and 30 days of refeeding with 100, 200, and 400 mg/kg of AA supplementation. AA addition increased cell diameter and the expression of anabolic and cell proliferation genes in vitro. In vivo, 400 mg/kg of AA increased anabolic and proliferative genes expression at 6 h of refeeding, the fiber diameter and the expression of genes related to cell proliferation at 15 days, and the expression of catabolic and oxidative metabolism genes at 30 days. Catalase activity remained low in the higher supplementation group. In conclusion, AA directly affected the isolated muscle cells, and the higher AA supplementation positively influenced muscle growth after fasting.     

Methacrylate monomer as an alternative to styrene in typical polyester–styrene copolymers

This study presents the research on the influence of crosslinking monomers [styrene and diethylene glycol dimethacrylate (DEGDMA)] on the properties of unsaturated polyester resins (UPRs). Syntheses of the unsaturated polyesters (UPs) modified with benzyl alcohol were carried out. Then, each polyester was used in preparation of five resin solutions with different amounts of crosslinking monomers acting as reactive diluents. These diluents improve the processability of UPs reducing their viscosities. They also take part in crosslinking of resins during copolymerization process. The properties of the prepared UPRs systems were investigated before and after the curing process. The measurements of their viscosity, reactivity, mechanical properties, thermal stability (thermogravimetry), and dynamic mechanical analysis were performed. Resins where DEGDMA was used as reactive diluent were characterized by the largest viscosities in comparison to styrene ones. The type of the used monomer influenced also degree of the resin crosslinking. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47735.     

Modell zum turbulenten Wärmeübergang in Rohren auf der Basis radialer und axialer Turbulenzintensitäten für Newtonsche Fluide

Zusammenfassung Ausgehend von vereinfachenden Annahmen zum Verlauf der radialen und axialen Geschwindigkeitsschwankungen in einem turbulent durchstr?mten Rohr wird eine den W?rmetransport beschreibende Differentialgleichung aufgestellt und numerisch gel?st. Es zeigt sich für den Fall der thermisch ausgebildeten Str?mung bei konstanter Wandtemperatur, da? bei Newtonschen Fluiden die über dem Rohrquerschnitt vorliegende Mitteltemperatur („Mischtemperatur”) stets in einem Wandabstand von ca. 0,3·Rohrradius im radialen Temperaturprofil auftritt. Aufgrund dieses Sachverhalts kann mit Hilfe eines einfachen Widerstandsmodells ein Parameter R_T relativ schnell an experimentelle Werte bzw. entsprechende Gebrauchsformeln angepa?t werden. Eine überprüfung mit dem in der Literatur h?ufig angewendeten Ansatz, bei dem ein turbulenter W?rmeaustauschkoeffizient ε _q (eddy diffusity of heat) definiert wird, zeigt die Gültigkeit der durchgeführten Vereinfachungen. Mit der Modellvorstellung kann auch der W?rmeübergang nicht-Newtonscher Flüssigkeiten (z.B. reibungsmindernde Polymerl?sungen) beschrieben werden, wenn deren Turbulenzintensit?ten durch Messungen gegeben sind.     

Stability and calorimetric studies of silico‐ferrites of calcium aluminum and magnesium

In a systematic study on silico‐ferrites of calcium aluminum and magnesium (SFCA phases) this investigation focuses on synthesis of silicon‐free SFCA‐type compounds with low‐MgO contents (~1.00 apfu—atoms per formula unit). Previous studies revealed the existence of iron‐rich SFCA phases similar to the SFCA‐I structure with the chemical composition Ca₃MgAl₆Fe₁₀O₂₈ (Metall Mater Trans B. 2017;48:2207). The experimental results in the quaternary Fe₂O₃‐CaO‐Al₂O₃‐MgO system confirm large stability fields of 2 silicon‐free ferrites FCAM‐I and FCAM‐III, which are members of the homologous series M_14+6nO_20+8n (n = 1, 2). Starting with compositions corresponding to Ca₃MgAl_xFe_16‐xO₂₈ (with increasing aluminum content from x = 0‐12 apfu), it was possible to synthesize these phases with an x‐value ≥2 apfu, which corresponds to Al₂O₃ contents ≥7.14 wt%. Synthesis of pure silicon‐free ferrites with n = 1 (FCAM‐I) and 2 (FCAM‐III) and silicon‐bearing ferrites with n = 0 (SFCA) was possible. Samples were characterized by electron probe microanalysis, powder diffraction, and subsequently studied using relaxation calorimetry measurements in combination with differential scanning calorimetry for determination of the heat capacities and standard entropies S°(298). The corresponding values are S°(298) = 650.3 ± 4.6 J/mol·K for SFCA, S°(298) = 864.5 ± 6.1 J/mol·K for FCAM‐I, and S°(298) = 1206.2 ± 8.4 J/mol·K for FCAM‐III. These thermodynamic data are a step toward a rigorous quantitative thermodynamic modeling of the iron ore sintering process.     

ETL workflow reparation by means of case-based reasoning

Data sources (DSs) being integrated in a data warehouse frequently change their structures/schemas. As a consequence, in many cases, an already deployed ETL workflow stops its execution, yielding errors. Since in big companies the number of ETL workflows may reach dozens of thousands and since structural changes of DSs are frequent, an automatic repair of an ETL workflow after such changes is of high practical importance. In our approach, we developed a framework, called E-ETL, for handling the evolution of an ETL layer. In the framework, an ETL workflow is semi-automatically or automatically (depending on a case) repaired as the result of structural changes in DSs, so that it works with the changed DSs. E-ETL supports two different repair methods, namely: (1) user defined rules, (2) and Case-Based Reasoning. In this paper, we present how Case-Based Reasoning may be applied to repairing ETL workflows. In particular, we contribute an algorithm for selecting the most suitable case for a given ETL evolution problem. The algorithm applies a technique for reducing cases in order to make them more universal and capable of solving more problems. The algorithm has been implemented in prototype E-ETL and evaluated experimentally. The obtained results are also discussed in this paper.     

Representation and analysis of enterprise models with semantic techniques: an application to ArchiMate,e3value and business model canvas

Enterprise models assist the governance and transformation of organizations through the specification, communication and analysis of strategy, goals, processes, information, along with the underlying application and technological infrastructure. Such models cross-cut different concerns and are often conceptualized using domain-specific modelling languages. This paper explores the application of graph-based semantic techniques to specify, integrate and analyse multiple, heterogeneous enterprise models. In particular, the proposal described in this paper (1) specifies enterprise models as ontological schemas, (2) uses transformation mapping functions to integrate the ontological schemas and (3) analyses the integrated schemas with graph querying and logical inference. The proposal is evaluated through a scenario that integrates three distinct enterprise modelling languages: the business model canvas, e3value, and the business layer of the ArchiMate language. The results show, on the one hand, that the graph-based approach is able to handle the specification, integration and analysis of enterprise models represented with different modelling languages and, on the other, that the integration challenge resides in defining appropriate mapping functions between the schemas.