Explore the vast range of titles available.

We demonstrate a proof of concept for magnetically-driven 2D cells organization on superparamagnetic micromagnets fabricated by laser direct writing via two photon polymerization (LDW via TPP) of a photopolymerizable superparamagnetic composite. The composite consisted of a commercially available, biocompatible photopolymer (Ormocore) mixed with 4 mg/mL superparamagnetic nanoparticles (MNPs). The micromagnets were designed in the shape of squares with 70 µm lateral dimension. To minimize the role of topographical cues on the cellular attachment, we fabricated 2D microarrays similar with a chessboard: the superparamagnetic micromagnets alternated with non-magnetic areas of identical shape and lateral size as the micromagnets, made from Ormocore by LDW via TPP. The height difference between the superparamagnetic and non-magnetic areas was of ~ 6 µm. In the absence of a static magnetic field, MNPs-free fibroblasts attached uniformly on the entire 2D microarray, with no preference for the superparamagnetic or non-magnetic areas. Under a static magnetic field of 1.3 T, the fibroblasts attached exclusively on the superparamagnetic micromagnets, resulting a precise 2D cell organization on the chessboard-like microarray. The described method has significant potential for fabricating biocompatible micromagnets with well-defined geometries for building skin grafts adapted for optimum tissue integration, starting from single cell manipulation up to the engineering of whole tissues.

Aluminum-silicon alloys have become a popular choice for applications in the automotive and aerospace industries and have proven themselves through their fault-tolerant processability and respectable static properties at comparatively low costs. Current research has focused on a water jet gun for firefighters. This is an essential device used by firefighters and other emergency response teams to control and direct the flow of water from fire hoses. The role of the research is also to understand the performance of enriched materials in the construction of water guns for firefighters. Through a series of friction and wear tests on aluminumbased alloys, the research establishes correlations between wear performance and the mechanical properties of the materials. These findings provide critical insights into the design and performance of pressure guns, thereby helping to increase the safety and effectiveness of firefighting equipment. The results of the study provide practical recommendations for increasing the durability and functionality of essential firefighting tools.

As the market of the SW based electronic components in the automotive industry is increasing with high speed, both Original Equipment Manufacturers (OEM) and suppliers need to find solutions for delivering quality products which fulfil customer requirements and safety regulations. One measure of quality is represented by the number of Customer Defects. But how to normalize the Number of Customer Defects metric in order to measure and compare the results of this metric for any kind of automotive SW development project, independent of the complexity and code size? We experienced one possible solution by measuring the metric Customer Defects per Lines of Code on several projects. We analysed if and how code size and implicitly complexity influence the quality of the Automotive SW Development applications. Are complex systems more prone to errors? Should we invest in quality for low complexity systems? These are the main questions we tried to answer.

Machining with tool that have cutting edge radius provides components with high fatigue strength, microhardness of a large surface layer and plastic deformation. Finite element simulations of the cutting process give a better knowledge of the chip generation phenomenon, heat generation in the machining area, stress and temperature field results. This study emphasizes the true importance of the mathematical model that underlies the shape of the tool in the pre-processing steps of finite element analysis. The argument is that its achievement and definition depend on the network difficulty. This research purpose is to perform simulations series of orthogonal machining with different radius and depth of cut. In this way, conclusions on the impact of these variations on the whole cutting process were drawn. The finite element application used is Deform 2D, the Lagrange incremental method and the Johnson-Cook material model. The temperature distribution, stress distribution, von Mises stress distribution, effects on specific tool pressure and wear, and fluctuations in the cutting resistance of the tool tip and C45 workpiece were analyzed.

This work concerns the study of the coatings for the ultrasound frequency range as a quasi one-dimensional phononic crystal structure protecting a sea object against high resolution active sonar in the frequency range most commonly found for this type of equipment. The topology of the examined structure was optimized to obtain a band gap in the 2.2-2.3 MHz frequency band. For this purpose, a genetic algorithm was used, which allows for optimal distribution of individual elements of the ultrasound multilayer composite. By optimal distribution is meant to achieve a structure that will allow minimal reflectance in a given frequency range without height reflectance peaks with a small half width. Analysis of the wave propagation was made using the Transfer Matrix Method (TMM). As part of the research, 15 and 20-layer structures with reflectance at the level of 0.23% and 0.18%, respectively, were obtained. Increasing the number of layers in the analyzed structures resulted in finding such a distribution in which a narrow band of low reflectance was obtained, such distributions could also be used as bandpass filters. The use of a genetic algorithm for designing allows to obtain modern coatings, the characteristics of which result from the structure.

An alternative for Ordinary Portland cement (OPC) consumption is the production and integration of green cement. In other words, the clinker consumption has to be replaced with new low-carbon binders. A possible solution was introduced by the geopolymerisation technology. However, the alkaline activation of geopolymers offers the possibility of obtaining greener materials with high properties, superior to OPC, but due to the high price of sodium silicate, their industrial use is limited. In the past few years, a new activator has been discovered, namely phosphoric acid. This study approaches the obtaining of coal ash-based geopolymers activated with acid solution cured at room temperature. Accordingly, phosphoric acid, 85% by mass, was diluted in distilled water to obtain a corresponding activation solution for H3PO4/Al2O3 ratio of 1.0 and two types of geopolymers were ambient cured (22°C ±2°C). Moreover, to evaluate the geopolymerisation potential of this system (coal ash – phosphoric acid), SEM and EDS analysis was performed to investigate their morphologic characteristics.

The product development process is a very challenging one, especially in the case of the automotive industry. The actual constructions require performance and quality while focusing on mechanical performance, lightweight and cost-effective. Thus, the virtual development stage is critical. Once the product is validated according to its geometrical definition and features, it is necessary to evaluate its mechanical performance. This process is usually performed using numerical simulation methods. In this paper, the numerical process performed for the validation of a safety part is discussed. As a specific feature, the assembly is finished using a riveting process. The manufacturing process’s influence on the assembly’s mechanical performance is further investigated. A discussion of the methods available for the design validation summarizes the finding of this specific work.

Generally, the metallic implants do not exhibit any bio-integration properties in contact with bone tissues. To improve the interfacial properties of metallic implants in contact with bone, the coatings with thin biocompatible films are used. Two methods to coating titanium implants with hydroxyapatite are described. The first is a two phase method, where by cathodic polarization is deposed a monetite film followed by an alkaline treatment when the monetite is converted to hydroxyapatite. The second method is a biomimetic deposition on an alkaline activate titanium surface, using a five time more concentrated simulated body fluid (5xSBF). After deposition this samples was drying at 120℃ and was sintered at 700℃ for three hours. Optical microscopy, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray (EDX) were used to characterize structure, morphology and compositions of the deposed films. In this study, electrochemical deposition and biomimetic deposition of hydroxyapatite are compared.

Among the synthetic media used in the industry the most advantageous are the substances resulting as secondary products from the wood or paper processing industry, as carboxymethyl cellulose. Carboxymethyl cellulose dissolved in water is a synthetic quenching environment used in large tempering basin. Due to the dimensions of the quenching basins, the quenching medium is used repeatedly, which leads to its thermal degradation. The degree of modification of the cooling properties and corrosion behavior of aqueous solutions of carboxymethyl cellulose in the thermal range 800-50°C were studied. The changes in the physicochemical properties such as density, pH, specific heat, diffusivity were studied. These characteristics were found to extert major effect on cooling characteristics during tempering. At the same time, the technological characteristics of cooling were also studied. The specific cooling curve of the medium and thermally degraded compared with the characteristics of classic quenching media such as water and heat treatment oil was analyzed. This study provides guidance on maintaining the specific cooling characteristics of a tempering medium after repeated uses.

Production of Ti-based alloys with non-toxic elements give the possibility to control the market of medical applications, using alloys with appropriate properties for human body, contributing to improving the health of the population. Determination of parameters of atomic and magnetic structure of functional biomaterials demonstrating interesting physical phenomena and being promising for medical applications in a wide range of thermodynamic parameters; exploration of the role of cluster aggregation in the formation of physical properties. Paper is about the obtaining of the new titanium system alloys, the determining their characteristics and structure, and obtaining information concerning phase transitions and some mechanical properties. Ti15Mo7ZrxTa (5 wt.%, 10 wt.% and 15 wt.%) alloys developed shows a predominant β phase highlighted by optical microstructure and XRD patterns. A very low young modulus of alloys was obtained (43-51 GPa) which recommends them as very good alloys for orthopedic applications.