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Anticorrosive nanomaterials of the type Zn₃Nb₂O₈ undoped and doped with trivalent Er³⁺ ions in saline environment
Get PDFThis study involvs the depositions of metal-oxide films via the spin-coating method, using pseudo-binary Zn3Nb2O8 oxides, both undoped and doped with Er3+ ions, synthesized hydrothermally on metallic substrates. Following the preparation of the thin films, electrochemical method were employed to evaluate their corrosion resistance and to validate their potential as corrosion inhibitors. The tests were cared out using a Voltalab PGZ 402 potentiostat connected to a threeelectrode elecrochemical cell, with the working electrodes consisting of steels discs coated with the thin films. The working parameteres included a potential range set between -1.3V and -0.6V and a scane rate of 1mV/s. The measurements were performed at a temperature of 23°C. The open circuit potential (OCP) of the modified electrodes was monitored for 30minutes prior to polarization. The corrosive medium used for the tests was a 0.3 M NaCl saline solution
Formulation of functional orange jellies enriched with rosehip powder
Get PDFThe contemporary food industry increasingly focuses on developing functional products that meet consumer demand for a healthy and balanced diet. This study aimed to develop healthier orange jelly formulations by incorporating rosehip powder (RP), a valuable unconventional ingredient rich in bioactive compounds. In this study, RP was incorporated into a conventional orange juice jelly recipe at concentrations of 0% (control), 2%, 4%, and 6% (w/w). Both the rosehip powder and the resulting jelly formulations were analyzed for total phenolic content (TPC), total flavonoid content (TFC), vitamin C, and antioxidant capacity, expressed as ferric reducing antioxidant power (FRAP), as key indicators of their functional properties. The rosehip powder exhibited high levels of total phenolic content (TPC: 2015.89 mg GAE/100 g d.w.), total flavonoids (TFC: 1280.42 mg QE/100 g d.w.), vitamin C (992.71 mg/100 g d.w.), and antioxidant capacity measured as FRAP (469.38 µM Fe²⁺/g d.w.). By supplementing orange jelly with RP at levels of 2%, 4%, and 6%, increases of 8.93%, 17.19%, and 25.81% in TPC, 9.73%, 20.48%, and 28.91% in TFC, 15.88%, 32.34%, and 46.51% in FRAP, and 31.73%, 61.70%, and 87.05% in vitamin C were observed compared to the control. These results indicate that RP is a rich source of polyphenols and vitamin C, substantially contributing to the antioxidant activity and functional properties of food products. In the RP-enriched jelly formulations, levels of bioactive compounds and antioxidant activity increased progressively, reaching their highest values in the 6% RP sample. Overall, the study demonstrates that RP represents a promising functional ingredient for jelly fortification. Its incorporation enhances the antioxidant profile, offering a promising strategy for developing value-added, healthsupporting foods
Obtaining and characterization of TiO₂ by dip coating for UV-blocking applications
Get PDFThis study reports on the synthesis and characterization of thin films of titanium dioxide (TiO₂) with a focus on their ultraviolet (UV) blocking properties. The thin films were obtained through a sol-gel method, deposited by dip-coating, and subsequently annealed to enhance structural and optical properties. Various precursor solutions, solvents, and deposition speeds were investigated to optimize film quality. The films were analyzed using X-ray diffraction (XRD), Raman spectroscopy, and UV-Vis-NIR spectroscopy. Results showed that the deposited films were well-crystallized, highly transparent in the visible range, and had efficient UV-blocking properties. The results suggest that these thin films are promising candidates for applications in protective coatings and UV filters for high-temperature working materials, combining effective UV shielding with favorable optical transparency in the visible spectrum at high temperatures
Determination of biometric and chemical parameters in the fruits of some quince varieties
Get PDFQuince (Cydonia oblonga Miller) is a commonly cultivated plant throughout the world, known for centuries for its valuable nutritional and curative properties. Although quince fruits are extremely aromatic, due to their high hardness and sour, astringent [10] and bitter taste, they are not suitable for direct consumption in unprocessed form. However, they are an important raw material in fruit processing, for example, in the production of jams, jellies and juices. Quince fruits fall into the category of temperate fruits, so their shelf life can be predicted. Considering that technological processing affects not only the organoleptic properties and shelf life, but also the functional properties of the fruits, For this study, 20 fruits from 4 quince varieties (Bereczki_RO; Champion_HU; De Portugalia_TR; Constantinopol_RO) that were purchased from the supermarket, in 2024, were analyzed, the fruits were studied from a biometric and qualitative point of view, tracking the following parameters: large diameter (mm), small diameter (mm), height (mm), weight (g), soluble dry matter (0Brix), sugar percentage (%) and fruit firmness. From the results obtained for the physical (biometric)-chemical parameters, the following results can be observed: for the Bereczki_RO quinces: the average of the large diameter values is 80.42 mm, the highest value was recorded by the Constantinopol_RO variety, with a value of 88.65 mm, with an average of the experiment of 82.48 mm. Regarding the soluble dry matter (0Brix)% and the percentage of sugars, it can be observed that the Bereczki_RO variety recorded the highest value for these parameters, these being 14.01(0Brix), respectively 12.39%
HRMS analysis of surfactin-type components produced by Bacillus strains isolated from environmental samples
Get PDFSurfactin-type components produced by Bacillus species are cyclic lipopeptides with broad potential across environmental sustainability, agriculture, and environmental protection. In addition to their ecological relevance, these compounds also exhibit practical bioactivities such as antibacterial, antifungal, antiviral, and antitumor properties. In this study, we successfully performed the taxonomic identification of 40 Bacillus strains isolated from fungal compost. The surfactin production by each strain, as well as the individual surfactin variants, was examined by High-Resolution Mass Spectrometry (HRMS). Of the 40 Bacillus strains, 18 were found to produce surfactins, representing members of the species B. subtilis, B. halotolerans, B. licheniformis, and B. velezensis. A total of 109 distinct surfactin variants were identified among the isolates. Following the spectrometric analysis, biological assessments were performed to determine the antimicrobial activity of the surfactin producing strains against phitopathogenic bacteria and fungi. B. subtilis strains were generally effective against phytopathogenic bacteria. For phytopathogenic fungi, B. halotolerans strains demonstrated the strongest activity. In general, our findings on the production of surfactin by Bacillus isolates provide a solid foundation for the identification of promising candidates for future biocontrol applications
Prolongation of solutions and Lyapunov stability for Stieltjes dynamical systems
Get PDFIn this article, we present Lyapunov-type results to study the stability of an equilibrium of a Stieltjes dynamical system. We utilize prolongation results to establish the global existence of the maximal solution. Using Lyapunov’s second method, we establish results of stability (resp. uniform stability) and asymptotic stability (resp. asymptotic uniform stability). Finally, we present examples and real-life applications to study asymptotic stability of equilibria in two population dynamics models
Bifurcation in two parameters for a quasilinear Schrödinger equation
Get PDFThis paper deals with existence and multiplicity of positive solutions for the quasilinear Schrödinger equation −∆u − λm(x)u∆(u 2 ) = f(µ, x, u) in Ω, u = 0 on ∂Ω. where Ω is a bounded open domain in RN with smooth boundary and m is a bounded non negative continuous function. Under suitable assumptions on the asymptotically linear f , we use bifurcation theory to analyze the set of positive solutions
On the set of eigenvalues for some classes of coercive and noncoercive problems involving (2, p(x))-Laplacian-like operators
Get PDFWe consider a class of double-phase nonlinear eigenvalue problems driven by a (2, ϕ)-Laplace-like operator: −∆u − ε div [ϕ(x, |∇u|)∇u] = λ(u + ε) in a domain Ω, subject to Dirichlet boundary conditions, where Ω is a bounded subset of RN with a smooth boundary. Here, ε > 0, and the potential function ϕ exhibits p(x)-variable growth. We establish several results on the existence and concentration of eigenvalues for this problem, focusing on the influence of the growth behavior of the potential function ϕ, specifically through the interaction between the variable growth exponent p(x) and the constant growth exponent 2. The proofs rely on variational arguments based on the Direct Method in the Calculus of Variations, Ekeland’s variational principle, and energy estimates
