Key Engineering Materials Vol. 885

Abstract: Recently the high strength steel has been applied in the automotive more and more widely. In this study, the effect of blank shape on the formability of an automotive part was analyzed. The three kinds of blank shapes were chosen, including a rectangular shaped blank, a blank with two corners cut straightly and a blank with two corners cut in curve. The effect of the variable blank holder force on the formability was studied. The four kinds of variable blank holder force were applied. The blank shape in this part is the blank with two corners cut curve. The results show that the blank with two corners curve is the most suitable. And the blank holder force from 1000 kN to 1500 kN is the most useful for the formability.

Abstract: The investigation of new materials that have properties such as resistance to high temperatures, wear resistance, rigidity, and low weight, involves the use of technological processes with more and more advantages. For this purpose, mechanical alloying is a widely used technique, which consist of high-energy impact between balls inside a container, where constant collisions deform and fracture the material, achieving the alloy of the particles in a solid state. This work focuses on the Vickers hardness evaluation of the copper matrix alloy with 4% Pb, 4% Sn and 4% Zn, in an oxidizing atmosphere, sintered at 800 °C and 900 °C, using milling times of 3 hours, 6 hours and 9 hours. The results show that there is a relationship between the hardness obtained, in the two groups of specimens at 800 ° C and 900 ° C, with the grinding time and the sintering temperature, among others used in the process. An average maximum hardness of 53.4 HV was obtained.

Abstract: In this report, we proposed a MALDI mass spectrometry-based approach to study the formation of glycated species by coupling carbonyl aldehydes of sugar and molecules nucleophilic groups via enzymatic oxidation. The proposed enzymatic glycation in vitro could be a simple method to obtain well-defined substrates useful to study biological properties and activities of proteins in clinical samples, during oxidative stress and disease.

Abstract: We proposed a MALDI mass spectrometry based approach to characterize walnut allergens. The strategy is based on the extraction of hydro-soluble tissue proteins followed by protein fractionation and mass-spectrometry analysis. Linear MALDI was adopted to evaluate the intact protein mass information and the presence of glycoproteins.

Abstract: The research on phenolic compound degradation using chemical oxidation methods in a plasma reactor was performed with an Ozone-Plasma Hybrid Reactor (RHOP). This device operates by combining ozonation reactions in the liquid plasma within the reaction room. Furthermore, Ozone gas as a reagent is produced by the standard ozonator type Resun RSO-9805 made in Hong Kong and fed into this device, where the liquid phase is mixed within the injector. This way, the two-phase mixture reacts more intensively in RHOP. Also, this combination is designed to intensify hydroxyl radicals while the liquid phase is in an alkaline condition constantly exposed to plasma. The results demonstrated a continuous circulation for 2 hours at the initial concentration of 50 ppm for p-chlorophenol with a volume of 2 liters. This further obtained an 83.98% removal rate and 42.19% COD value decrease.

Abstract: Hydrogels are cross-linked polymeric structures, which consist of up to approximately 90% water, the remainder is polymer chain. Retention of large volumes of water in the intermolecular space is related to the presence of hydrophilic functional groups in the network. The unique hydrogels properties, such as porosity, and biological and mechanical properties, make them suitable for a wide range of applications, especially in the medical sector. Furthermore, ease of modification and good printability are expected in 3D bioprinting technologies. Nevertheless, to maintain their structure and softness, hydrogels must be stored in suitable conditions to prevent water vaporization. The water removal from the hydrogel network results in weight reduction, structural and volumetric changes. It is a considerable challenge for the printouts manufactured by 3D bioprinting technology, where hydrogel products are exposed to drying during the production process, which may affect their shape change and shrinkage. The paper presents a crosslinking process of a hydrogel-based on sodium alginate and the shrinkage of dried hydrogels depending on the crosslinking procedure. An investigation focused on the alginate hydrogel water content, as well as shrinkage of alginate hydrogel degree depending on the concentration of the cross-linking (CaCl₂) solution and the duration of the process. For longer cross-linking time or using higher cross-linking agent concentration, the cross-linking was more efficient. However, it is necessary to optimize the parameters for the bioprinting process.

Abstract: There is the need for the use of biodegradable optical filters. This concept of this work is to solve the problems of electronic waste and enhance spectra filtering in photovoltaic (PV) module. The extract of the Ixora plant was used for this experiment. The extract was doped with 0.05 m of copper. The voltage peak analysis (VPA) was used to analyze the chemical stability of the filter. It was observed that the filter was chemically stable at certain time of the day due to temperature variations on the PV module.

Abstract: The evolution of semiconductor from the conventional type to organic semiconductor has not convincingly shown that it is eco-friendly both in the short and long term. This research presents the green solution bio-semiconductor that was synthesized from zinc coated carica papaya. It was observed that carica papaya extracts do not respond significantly to the extracting solution (methanol, ethanol and butanol). The band gap of sample 1 (extract in methanol solution), sample 2 (extract in ethanol solution) and sample 3 (extract in butanol solution) was calculated as 1.98 eV, 2.01eV and 1.93 eV respectively. Further research is therefore recommended for the perfection of the bio-semiconductor.

Abstract: Innovative preparation strategies for nanomaterial functionalization were proposed to provide novel tool to be used as drug delivery vectors for biomedical applications. In particular, three different carbon nanotubes were considered in this study such as the very small CNTs, the carboxylated CNTs (CNT-COOH) and the buckypapers and two polymers were used to study the functionalization. Different preparation procedures were investigated by thermogravimetric analysis (TGA), including the selection of the most performing polymer to be linked to the nanomaterial between PEI and PAMAM, the percentage of the polymer and the time of suspension. To simultaneously evaluate all these variables, an experimental design was planned and the recorded data were processed by chemometrics to identify the preparing procedure providing new nanomaterials able to conjugate microRNAs and to transfect efficiently endothelial cells.