Catechin and epicatechin in testa and their association with bioactive compounds in kernels of cashew nut (Anacardium occidentale L.)

Catechins in testa and bioactive compounds in testa-free and testa-containing kernels of cashew nuts were analysed. The cashew nut testa contained (+)-catechin and (−)-epicatechin with concentrations of 5.70 and 4.46 g per kg DM, respectively. Testa-containing kernels revealed significantly higher levels of β-carotene (218 vs. 89.6 μg/kg DM), lutein (525 vs. 292 μg/kg DM), and α-tocopherol (10.1 vs. 2.4 mg/kg DM), similar amounts of zeaxanthin (7.0 vs. 7.1 μg/kg DM), γ-tocopherol (10.6 vs. 10.1 mg/kg DM), stearic acid (41 vs. 43 g/kg DM), oleic acid (214 vs. 219 g/kg DM) and linoleic acid (69 vs. 62 g/kg DM), but a lower concentration of thiamine (3.0 vs. 10.7 mg/kg DM) in comparison to testa-free samples. The testa-containing kernels provide high amounts of catechins and higher concentrations of β-carotene, lutein and α-tocopherol than do testa-free cashew nut kernels. This could have potential health benefits for consumers.     

Effect of the Slag Composition on the Process Behavior,Energy Consumption,and Nonmetallic Inclusions during Electroslag Remelting

Electroslag remelting (ESR) is an important process to produce high-quality tool steels. The slag composition has a strong effect on the remelting behavior, particularly on energy consumption and the removal of nonmetallic inclusions (NMI). The latter aspect is strongly related to chemical reactions between the slag and the metal and determines the necessary composition of the slag. Also, the electrical conductivity of the slag is determined by the slag composition, and a high resistivity is desirable. The effect of different slag compositions with 0%–60% CaF₂ and a corresponding wide range of electrical conductivities is investigated regarding slag movement, slag surface temperature, and slag skin thickness, as well as their impact on chemical reactions and the removal of NMI. Therefore, a laboratory-scale ESR unit and the plastic mold steel X40Cr14 are used for the experimental trials. The results show a strong impact on the remelting behavior as well as on the specific energy consumption ranging from ≈900 to over 1700 kWh h⁻¹. The findings from the chemical analysis and detection of NMI indicate that a similar metallurgical behavior is feasible, leading to comparable amounts of dominantly Al₂O₃–MgO-type inclusions with some variation due to different activities in the slag.     

Influence of Partitioning Effects on the Retained Austenite Content and Properties of Martensitic Stainless Steel

The effect of a quenching and partitioning (Q&P) heat treatment with a quenching temperature (T_Q) range from 20 to 190 °C is investigated for two martensitic stainless tool steels X40Cr14 and “X25CrN13”, focusing on microstructural evolution, hardness, and toughness. The influence on the retained austenite (RA) content, when replacing part of carbon with nitrogen, is of core interest. The amount of RA is analyzed by X-ray diffraction and is additionally proved with electron backscatter diffraction, and the RA content is thermodynamically calculated. Subsequently, the effect of the microstructure on toughness and hardness is investigated. For both steels, the toughness maximum is reached in the region of the RA maximum. The “X25CrN13” attains higher toughness at higher RA contents. Higher RA contents do not benefit X40Cr14. Furthermore, the effect of double tempering at higher tempering temperatures after Q&P on the steels is investigated. Besides RA contents and hardness, dilatometer curves are used to evaluate the formation of fresh martensite in the microstructure. The secondary hardness maximum of “X25CrN13” is reached at 500 °C and that of X40Cr14 is at 480 °C. For double tempering temperature at 520 °C, T_Q has little effect on toughness, and “X25CrN13” shows better values.     

Structural Aspects of Native and Acid or Enzyme Degraded Amylopectins - a 13C NMR Study

¹³C NMR signal assignments were achieved for amylopectin (from waxy maize starch) dissolved in dimethylsulfoxide mainly by comparison with the corresponding amylose spectrum and chemical shift arguments. From these data a branching degree of amylose and amylopectin of 1.4±0.5% and 6.0±0.7% could be estimated. Investigation of acid and enzyme degraded amylopectins by means of this method revealed that cleavage by these methods proceeded in an analogous manner. Thus, viewed from the standpoint of structural aspects they yielded virtually identical products.     

Linking Interfacial Bonding and Thermal Conductivity in Molecularly-Confined Polymer-Glass Nanocomposites with Ultra-High Interfacial Density

Thermal transport in polymer nanocomposites becomes dependent on the interfacial thermal conductance due to the ultra-high density of the internal interfaces when the polymer and filler domains are intimately mixed at the nanoscale. However, there is a lack of experimental measurements that can link the thermal conductance across the interfaces to the chemistry and bonding between the polymer molecules and the glass surface. Characterizing the thermal properties of amorphous composites are a particular challenge as their low intrinsic thermal conductivity leads to poor measurement sensitivity of the interfacial thermal conductance. To address this issue here, polymers are confined in porous organosilicates with high interfacial densities, stable composite structure, and varying surface chemistries. The thermal conductivities and fracture energies of the composites are measured with frequency dependent time-domain thermoreflectance (TDTR) and thin-film fracture testing, respectively. Effective medium theory (EMT) along with finite element analysis (FEA) is then used to uniquely extract the thermal boundary conductance (TBC) from the measured thermal conductivity of the composites. Changes in TBC are then linked to the hydrogen bonding between the polymer and organosilicate as quantified by Fourier-transform infrared (FTIR) and X-ray photoelectron (XPS) spectroscopy. This platform for analysis is a new paradigm in the experimental investigation of heat flow across constituent domains.     

Structure–property relationships of model chlorstrifluoroethylene oligomer compounds: Thermal stability

Low molecular weight chlorotrifluoroethylene (CTFE) oligomers have been the base fluid for an extensive DoD research and development programme for nonflammable hydraulic fluids, compatible elastomeric seals, components, and systems. To gain a more fundamental understanding of the effect of the specific isomers and other components of commercial CTFE fluids on the important fluid properties, model compounds were synthesised and their physical and chemical properties were determined. Thermal stability, in the presence of typical hardware system metals, is one of the more important properties and is discussed in relation to molecular structure. Two Microscale evaluation techniques were devised and validated. Optimum thermal stability is observed when the chlorines in the molecules are positioned as far apart as possible. In general, it was found that the compounds with larger amounts of chlorine were less stable and the positioning of the chlorine in the molecule had a lesser, but measurable effect.