Chromium nitride (CrNx) thin films were deposited by DC magnetron sputtering under increasing N2 flow to investigate their suitability for piezoresistive sensing applications. Structural, morphological, and electrical properties were systematically studied as a function of nitrogen incorporation. SEM and AFM analyses revealed a transition from coarse columnar metallic Cr to dense, nanocrystalline CrNx films as N2 flow increased, with a temporary amorphous-like regime at low nitrogen content (10 sccm). XRD confirmed the formation of the FCC-CrN phase for N2 flows >= 20 sccm, accompanied by an increase in crystallite size. Electrical resistivity similarly evolved from metallic behavior to semiconducting characteristics, driven by Cr-N bonding and reduced carrier density. Piezoresistive testing under cyclic bending demonstrated stable, repeatable, and linear responses for CrNx films at higher nitrogen content, yielding gauge factors of 3.9 +/- 0.3 (20 sccm) and 4.5 +/- 0.3 (25 sccm), outperforming pure Cr and comparable to high-performance metallic strain gauges. Thermoresistive evaluation revealed negative TCR values, typical of transition-metal nitrides, with improved thermal stability at higher nitrogen content. These findings establish sputtered CrNx thin films as promising candidates for multifunctional, mechanically robust, and thermally tolerant micro-scale pressure and temperature sensors, relevant for Industry 4.0/5.0 monitoring systems and flexible electronics.

Magnetic hyperthermia relies on the conversion of magnetic energy into heat by nanoparticles exposed to alternating magnetic fields, with specific loss power (SLP) being the key metric for heating efficiency. However, SLP can be evaluated at different levels of physical description, either from microscopic magnetic energy dissipation models or from macroscopic thermal analyses of calorimetric measurements, often without a clear distinction between their respective domains of validity. Here, we experimentally investigate how microscopic magnetic energy dissipation described by Linear Response Theory (LRT) and the macroscopic thermal response obtained from calorimetric energy-balance modeling provide complementary frameworks for interpreting SLP in superparamagnetic nanoparticle systems. By combining structural, morphological, magnetic, and magnetothermal characterizations, we determine parameters governing energy dissipation and evaluate the applicability of the LRT formalism under controlled small-field conditions. LRT predictions are directly compared with SLP values extracted from calorimetric heating curves analyzed using progressively more physically complete thermal energy-balance descriptions, from the adiabatic approximation to nonadiabatic regimes including conductive, convective, and radiative heat losses. We show that LRT calculations and calorimetric analyses reproduce consistent qualitative trends in heating efficiency, whereas quantitative differences arise from the distinct physical quantities represented by each framework. LRT describes microscopic magnetic energy dissipation under small-field conditions in terms of magnetic parameters that characterize the nanoparticle ensemble, whereas calorimetric energy-balance models capture the macroscopic thermal response of the nanoparticle suspension under realistic experimental conditions. Estimates of Neel and Brownian relaxation times indicate that relaxation is dominated by the Neel mechanism in the investigated systems with proximity to dynamic matching conditions governing relative heating efficiencies. As a consequence, the extracted SLP depends not only on magnetic relaxation processes but also on the level of physical completeness adopted in the thermal energy-balance description. These results demonstrate that LRT and calorimetric approaches should not be regarded as competing methods but as complementary levels of description of magnetic hyperthermia, providing experimental guidance for the consistent interpretation, comparison, and reporting of SLP values in magnetic nanoparticle systems.

The properties of a certain compound developed as a thin film can be influenced either by modifying the composition (mass ratio of the constituent elements) or, for a certain composition, by modifying the structural architecture. TiN compound, developed as a thin film, is well known, especially for its mechanical and tribological properties. For its stoichiometric aspect, it was found that modifying the structural design of the compound can expand its application area (from the perspective of thermal, electrical, optical properties). It is of particular interest to investigate the consequences of these structural architectural modifications taking into account the potential reduction in mechanical and tribological performance. This study focuses on the preparation of nanostructured thin films and the tailoring of their properties by employing inclined and zigzag-like growth architectures. To achieve this, TiN thin films were deposited on stainless steel and silicon substrates using Oblique Angle Deposition (OAD) with a DC reactive magnetron sputtering system. The mechanical and tribological properties of the films were found to be strongly influenced by their roughness and porosity values evolution, which resulted from the specific characteristics of the OAD geometry. As the deposition configuration shifted from conventional growth geometry (normal incidence) to OAD with inclined and zigzag geometries, both surface porosity and roughness values increased significantly due to the shadowing effect and comparatively low thermalization degrees. This led to a noticeable decrease in hardness and Young's modulus values, friction coefficient and wear rates, along with a reduced scratch resistance of the thin films. However, the values obtained were consistent with those reported in the literature, confirming the thin films' good applicability and suitability for a variety of applications. Hardness/Young's modulus values varied from about 27/260 GPa for the samples grown in the conventional geometry, reducing to approximately 13/210 GPa and about 10/190 GPa for the inclined and zigzag grown TiN films, respectively. The same reduction trend was also observed in the adhesion behaviour, where a decrease of about 50 % was observed for the critical loads (Lc2 and Lc3) when going from conventional to inclined and from this last to zigzag growth geometries. Finally, and keeping this tendency to a slight degradation of the mechanical and tribological behaviour, the friction coefficient, mu, increased from 0.20 for the conventional grown TiN sample to about 0.69 and 0.81 for the inclined and zigzag grown TiN sets.

This study reports on the influence of nanostructure design on the corrosion behaviour of titanium nitride (TiN) thin films, prepared by DC reactive magnetron sputtering, using the Glancing Angle Deposition (GLAD) technique. The primary objective was to explore how modifying the deposition geometry affects the growth design and surface features of TiN films (keeping roughly constant the N/Ti ratio) and compare these effects with those produced by changing the chemical composition within the same thin film system (N/Ti increasing ratios). For this, two groups of samples were prepared: Group 1 - the samples were prepared in the conventional geometry (normal growth) with varied nitrogen content (stoichiometric and non-stoichiometric films) and; Group 2 - the samples were prepared with modified growth geometries (inclined and zigzag, with increasing incidence angles), keeping an almost unchanged stoichiometry. The results revealed increased surface porosity and roughness for Group 2 films compared to Group 1, demonstrating that deposition geometry can affect more significantly the surface characteristics than the composition variations. Corrosion studies indicated that the films prepared within Group 2, despite having higher porosity, showed a more stable open circuit potential (OCP) and nobler values than the reference close-stoichiometric TiN 0.92 film (reference sample) from Group 1. However, potentiodynamic polarization curves suggested higher corrosion kinetics for Group 2 films, most likely due to their increased surface heterogeneities. Electrochemical impedance spectroscopy (EIS) confirmed these findings, showing lower corrosion resistance for films prepared with inclined and zigzag geometries, if compared to the films prepared in conventional geometry (Group 1 samples). This study advances the current state of the art on this film's responses, by demonstrating that tailoring nanostructure design through deposition geometry offers a promising approach to optimize the corrosion behaviour of TiNx without the need to change its composition.

Titanium-copper thin films were prepared by Glancing Angle Deposition (GLAD) to assess their suitability for temperature sensors, by measuring the temperature resistance coefficient (TCR). The films were deposited with zigzag and spiral architectures, while the substrate holder was maintained at a fixed angle of alpha = 20 degrees relative to the incident flux of the sputtered particles. The films were produced through DC co-deposition magnetron sputtering, using two targets of pure Ti and Cu. A wide range of compositions was achieved by varying the current on the Cu target from 6 mA up to 20 mA. The obtained architectures were stabilized through in-vacuum annealing treatments to minimize the hysteresis effects of the temperature on the electrical resistance of the films. The sheet resistance showed a direct correlation with the formation/precipitation of the Ti-Cu intermetallic phases in the film. The measured Temperature Coefficient of Resistance (TCR) values ranged from - 1.08x10- 3 to - 5.1x10- 3 degrees C- 1, closely resembling the absolute value of platinum's TCR (3.93x10- 3 degrees C- 1). Moreover, the elimination of hysteresis from the TCR plot and consistent results obtained during multiple cycles of heating and cooling highlight the potential of titanium copper thin films as promising alternatives for temperature sensors.

The growing interest in advancing microfluidic devices for manipulating fluids within micrometer-scale channels has prompted a shift in manufacturing practices, moving from single-component production to medium-size batches. This transition arises due to the impracticality of lab-scale manufacturing methods in accommodating the increased demand. This experimental study focuses on the design of master benchmarks 1–5, taking into consideration critical parameters such as rib width, height, and the relative width-to-height ratio. Notably, benchmarks 4 and 5 featured ribs that were strategically connected to the inlet, outlet, and reaction chamber of the master, enhancing their utility for subsequent replica production. Vat photopolymerization was employed for the fabrication of benchmarks 1–5, while replicas of benchmarks 4 and 5 were generated through polydimethylsiloxane casting. Dimensional investigations of the ribs and channels in both the master benchmarks and replicas were conducted using an optical technique validated through readability analysis based on the Michelson global contrast index. The primary goal was to evaluate the potential applicability of vat photopolymerization technology for efficiently producing microfluidic devices through a streamlined production process. Results indicate that the combination of vat photopolymerization followed by replication is well suited for achieving a minimum rib size of 25 µm in width and an aspect ratio of 1:12 for the master benchmark.

The widespread use of Cu-Zn alloys containing lead (Pb) in plumbing applications poses significant health risks due to potential Pb leaching into drinking water. In response to international legislation aimed at reducing or eliminating Pb in metal alloys, there is an increasing demand for environmentally friendly brass. In this experimental work, authors show that during the Laser Beam Powder Bed Fusion (PBF-LB) process of the CuZn42 (CW510L) alloy, small particles only a few microns large mixed with large particles that are hundreds of microns in size, are spattered from the material. Large particles show average Zn/Cu ratio around 0.22, while for small particles it increases up to 3, against a nominal value of 0.72 for the CW510L alloy. The fallout of such particles on the produced part enriches surface of Zn, thus altering the surface chemical composition with an increase in Zn concentration beyond the acceptance limit of 43 at.%. To restore the standard chemical composition of the surface, a treatment based on the ablation of the surface material by a laser beam was proposed. Results clearly show that, after the laser treatment, the chemical composition of the surface is completely restored, and the standard properties recovered.

This study investigated the impact of the nanostructure design of titanium nitride (TiNx) thin films on their optical, electrical and thermal properties. The growth designs of the films were tailored using conventional sputtering (series 1) and GLancing Angle Deposition (GLAD) geometries (series 2 and 3). The results showed the potential to modify the properties of thin films by adjusting their nanostructure design, rather than changing their composition. TiNx thin films prepared by GLAD, revealed wider and more significant variations in optical and electrical properties, while the thermal properties seemed to be more affected by the structural changes promoted by the N content in the films. GLAD geometries resulted in the reduction of the film's reflectivity, and colour coordinates, as well as an increase in the electrical resistivity. The thermal parameters of effusivity ratio and diffusivity were reduced as the N/Ti ratio increased.

The attachment or entrapment of microbial cells and enzymes are promising solutions for various industrial applications. When the traps are beads, they are dispersed in a fluidized bed in a vessel where a pump guarantees fresh liquid inflow and waste outflow without washing out the cells. Scientific papers report numerous types of cell entrapment, but most of their applications remain at the laboratory level. In the present research, rigid polymer beads were manufactured by two different additive manufacturing (AM) techniques in order to verify the economy, reusability, and stability of the traps, with a view toward a straightforward industrial application. The proposed solutions allowed for overcoming some of the drawbacks of traditional manufacturing solutions, such as the limited mechanical stability of gel traps, and they guaranteed the possibility of producing parts of constant quality with purposely designed exchange surfaces, which are unfeasible when using conventional processes. AM proved to be a viable manufacturing solution for beads with complex shapes of two different size ranges. A deep insight into the production and characteristics of beads manufactured by AM is provided. The paper provides biotechnologists with a manufacturing perspective, and the results can be directly applied to transit from the laboratory to the industrial scale.

Sea star wasting (SSW) disease, a massive and ongoing epidemic with unknown cause(s), has led to the rapid death and decimation of sea star populations with cascading ecological consequences. Changes in microbial community structure have been previously associated with SSW, however, it remains unknown if SSW-associated dysbiosis is a mechanism or artifact of disease progression, particularly in wild populations. Here, we compare the microbiomes of the sunflower sea star, Pycnopodia helianthoides, before (Naïve) and during (Exposed and Wasting) the initial outbreak in Southeast Alaska to identify changes and interactions in the microbial communities associated with sea star health and disease exposure. We found an increase in microbial diversity (both alpha and beta diversity) preceding signs of disease and an increase in abundance of facultative and obligate anaerobes (most notably Vibrio) in both Exposed (apparently healthy) and Wasting animals. Complementing these changes in microbial composition was the initial gain of metabolic functions upon disease exposure, and loss of function with signs of wasting. Using Bayesian network clustering, we found evidence of dysbiosis in the form of co-colonization of taxa appearing in large numbers among Exposed and Wasting individuals, in addition to the loss of communities associated with Naïve sea stars. These changes in community structure suggest a shared set of colonizing microbes that may be important in the initial stages of SSW. Together, these results provide several complementary perspectives in support of an early dysbiotic event preceding visible signs of SSW.

Appears in: EDULEARN23 Proceedings Publication year: 2023Pages: 29-38ISBN: 978-84-09-52151-7ISSN: 2340-1117doi: 10.21125/edulearn.2023.0030Conference name: 15th International Conference on Education and New Learning TechnologiesDates: 3-5 July, 2023Location: Palma, Spain

The digital environment and the businesses can no longer exist separately; the way in which entrepreneurs adapt to digital environments determines the future of the companies. By aiming to understand Romanian entrepreneurs' openness and the assets disposed for digitalisation, the authors performed a study which revealed different managerial approaches used in order to achieve digital entrepreneurial sustainability. With exploratory research, they (i) identified the strategic approaches of the businesses within the digital environment, (ii) analysed the importance of strategic objectives and the entrepreneurial vision, (iii) understood the long-term strategies and the costs of digitalisation, and (iv) analysed the future of the business in terms of cyber security. The study highlighted that no Romanian entrepreneur placed digitalisation as an independent objective for its company, showing that companies needed a proper digitalisation strategy correlated to the opportunities and threats of the business environment. Moreover, the Romanian entrepreneurs' knowledge in cyber security was low even though they were aware that it was imperative to control critical information and develop data security strategy so as to avoid data theft/loss in the company. All the findings favoured conceptualising a new Digital Sustainable Entrepreneurship Model based on owners' entrepreneurial visions and companies' strategic objectives alike, a guide-framework to remain competitive in a sustainable, ever-growing market.

Although additive manufacturing (AM) technologies have been rarely used to produce lead-containing brass, the same AM technologies have never been adopted to produce lead-free brass parts based on the CuZn42 alloy. This study aims to fill the gap, demonstrating the feasibility of lead-free brass alloys by laser powder bed fusion (LPBF) technology and investigating structural and mechanical properties of the produced specimens, focusing attention on the role of surface energy density on material properties. Starting from a raw powder of CuZn42 alloy containing α, β and γ brass phases, fully dense samples with high hardness values were obtained by LPBF. The structural and mechanical properties of the samples were investigated by scanning electron microscopy (SEM), energy-dispersive microanalysis (EDS), X-ray diffraction (XRD) and density and hardness measurements. Results showed that density, hardness and the relative amount of the brass phases depend on the surface energy density (SED) Es. The investigated range of SED allowed defining the process window ranging from 2 J/mm2 to 10 J/mm2, within which fully dense samples can be obtained. A linear dependence of hardness on density was also found, suggesting that deformation mechanisms are mainly due to the presence of residual pores and internal cavities rather than to microstructural features, such as the relative amount of brass phases and crystallographic defects. All results obtained in this work demonstrated, for the first time, that LPBF is suitable to produce components based on the CuZn42 alloy, and that structural and mechanical properties of the produced parts can be properly designed by controlling SED.

Within the frame of this work, the synthesis of silver nanoparticles (Ag NPs) and silver chloride nanoparticles (AgCl NPs) as mediated by microbes has been investigated. The nanoparticles were reduced from a silver nitrate precursor by the presence of bacteria, like Raoultella planticola and Pantoea agglomerans. The results show that the characteristic surface plasmon resonance absorption band occurs at about 440 nm. Nanoparticles were also characterized with the help of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), and X-ray diffraction (XRD), which showed the formation of spherical Ag/AgCl NPs with a centered cubic crystal structure and a mean particle size of around 10–50 nm. Assays for antimicrobial activity of the biosynthesized nanoparticles demonstrated meaningful results against microorganisms such as Staphylococcus aureus, Streptococcus pyogenes, Salmonella, and Bacillus amyloliquefaciens. Furthermore, this study shows that the combination of the obtained nanoparticles with standard antibiotics may be useful in the fight against emerging microbial drug resistance.

In this paper, we explore and modify the structural, mechanical, and decorative properties of films composed by TiN and Ti (N, C) with a wide range of N2 gas flow during the deposition in order to be used on orthodontic systems. The films were grown using reactive DC magnetron sputtering from a pure Ti target and customized with C pellets onto Si and stainless steel 316L substrates. The structural properties were studied using X-ray diffraction and scanning electron microscopy, while the mechanical ones were obtained through hardness, elastic modulus, and friction coefficient. Moreover, the wear rate has been measured under an artificial saliva medium to simulate the oral cavity. The color of the films deposited onto stainless steel 316 L substrate was characterized through CIELab color code. Our findings show that the addition of N2 and C in the Ti matrix improves the mechanical properties of the films. With the increase in the amount of N2 and C, the hardness reaches a value of 739 HV, higher than the one reported in the literature (600 HV), a low value of the coefficient of elasticity (8.0 GPa), and also a low friction coefficient (0.30). Moreover, with the addition of N2 and C in the Ti films, the color of the films changes from metallic aspect until “with” gold, which means that our coatings exhibit versatile mechanical and color characteristics to be used in orthodontic wires applications.

This paper aims at identifying the entrepreneurial opportunities for establishing innovative startups during and post COVID-19 crisis. To reach this goal, we conducted an exploratory study based on semi-structured interviews with 168 students who intend to involve themselves in entrepreneurship in their future career. The research started from the debates in literature regarding the huge negative impact of the COVID-19 crisis on economic development, which can jeopardize the achievement of United Nations Sustainable Development Goals. The research findings confirm the results of other studies regarding the vulnerability of startups during crises, the reason why they have to refocus on innovative businesses, especially based on information and communication technology (ICT). Such businesses are considered incentives of sustainable development. Other ideas highlighted the importance of social entrepreneurship for the management of startups. It means that startups should develop strong relationships with employees but also with other stakeholders, like companies in the same industry, the public sector, academia, and citizens. In addition, changing the business culture aiming at developing green business could be an inexpensive solution for developing a sustainable entrepreneurial ecosystem. These empirical results have implications for both business and the academic environment, which should cooperate in order to overcome the crisis. Such an approach could be used in the long run in order to manage other crises and to develop sustainable business.

The continuous development of modern industries rises the necessity for functionally graded materials. This research starts from the consideration that the incorporation of SiC particles in the molten aluminum alloy can be difficult due to the very low wettability of SiC particles. In order to increase their wettability, SiC particles were covered with a layer of metallic copper. The incorporation of SiC particles into the aluminum alloy mass was performed by centrifugal casting. The secondary hypoeutectic Al-Si alloy used in this study was elaborated within the crucible of a resistors heated furnace. The metallic coating of SiC particles, in addition to the effect of increasing their wettability by molten metal, also has a role in preventing the formation of aluminum carbide in case of heating above 700 °C. A great amount of attention was paid to the parameters used during the centrifugal casting process. The results showed that adjusting the proportion of SiC particles within the composite allows us to obtain values of the thermal expansion coefficient within previously established limits. The present work demonstrates that the coating of SiC particles covered with a thin layer of metallic Cu creates the conditions to easily incorporate them into the molten Al mass, thus obtaining FGMs with controlled properties.

The article focuses on the creation and the development of the entrepreneurial ecosystem around the innovation clusters. Clusters are believed to have a well-defined strategic approach aimed at boosting businesses’ sustainable development, especially if clusters are centred around small and middle-sized enterprises. Having undertaken a piece of phenomenological qualitative research, we found that large companies were more open to cooperation and sustainability than the small and middle-sized ones, thus initiating and developing innovation clusters around them (particularly in high-technologized industries such as the automotive and Information Technology). Additionally, we highlight that a sustainable entrepreneurial ecosystem is based on strong pillars, of which small companies’ capabilities, including the entrepreneurial ones, are innovation-driven, and place them in the centre of the innovation cluster. This piece of research also provides relevant insights for private and public organisations and policymakers in order to co-create a local innovation and entrepreneurship strategy. Our findings have implications for both cluster literature and the field of entrepreneurship.

This study reports the assessment of the mechanical properties of intermetallic titanium thin films, doped with different amounts of aluminium, copper, silver, and gold, aiming their use as biopotential electrodes for non-invasive physiological monitoring. The four binary thin film systems, Ti-Me (Me = Al, Cu, Ag, Au), were prepared by DC magnetron sputtering, placing different number of Me pellets on a pure Ti target. The use of a Ti-composed target gave rise to a wide range of compositions, resulting in three distinctive zones of (micro) structural features, identified in all the prepared systems. In the first zone, a Ti-rich one, the films behaved like solid solutions, developing Ti-like microstructures. As the Me/Ti atomic ratio increased, the formation of intermetallic phases played the leading role and it became possible to observe two different microstructural trends, clearly related to the Me type. This zone was identified as an intermetallic region. In the third zone, a Me-rich one, the microstructures displayed by the different films (Me/Ti > 1.0) showed to be dependent on the Ti solubility into Me. The assessment of the mechanical properties revealed an improved hardness and stiffness with the Me addition, directly related to the formation of intermetallic compounds in different degrees of crystallinity. Moreover, the adhesive strength between the substrate and the coating was higher for the films deposited in the intermetallic zone, more evident in the films prepared with Au, Cu and Ag, in this order. The hardness enhancement was especially evident for the thin films presenting microstructures typical of thin film metallic glasses (TFMGs), Ti-Au and Ti-Cu, about twice the values exhibited by the Ti-Al and Ti-Ag ones. Furthermore, the toughness of these metallic glass-like thin film systems was remarkable, more evident within the Ti-rich zone, presenting H/E ratios close to 0.1 and good elastic recoveries. In contrast, the typical columnar morphologies, combined with the brittle intermetallic structures of the Ti-Ag and Ti-Al films, proved to be less resistant to the plastic deformation (H/E < 0.04), despite the improved elasticity presented by the Ag-rich films.