Learning pathway for advanced science concepts approach: the study of magnetorezistive materials

AbstractAdvanced science concepts approach requires specific teaching and learning strategies calling on constructivism pedagogy to do. As there are a lot of basic knowledge to be settled down in a short time, teachers need to change their strategies of teaching in favor of the most efficient ones such is using gradation teaching. For a complex perspective of the theme: “the study of magnetorezistive materials” we designed a learning pathway based on learning route of cognitive states. As for a good painting is needed a large scale of tinted bases, for a successful learning process we need to start teaching common basic concepts going to advanced ones through intermediate concepts. A learning pathway describes the function of human brain: “all concepts are stored in the mind like in a department store”. Based on this similarity teachers can build routes/pathways of learning using constructivist strategies. Magnetorezistive materials are used largely in up to date industry and they need more attention in the context of understanding science behind the gadgets we use

Contributions to the knowledge of the evolution of Dâmbovita’ s agriculture

Ispas Stefan, Antohe Carmen. Contributions to the knowledge of the evolution of Dâmbovita’ s agriculture. In: Annales d'Université "Valahia" Târgovişte. Section d'Archéologie et d'Histoire, Tome 1, 1999. pp. 166-170

The Importance of Inquiry-Based Learning on Electric Circuit Models for Conceptual Understanding

AbstractStudents usually have difficulties to understand abstract concepts of electric circuits. Various electric circuit models are used to build comprehensive bridges between reality and models. In this study, effect of using the water circuit analogy on students’ conceptual understanding is explored. Sample divided into three groups. For experimental group I, electric circuit mental-models animated in their mind and applied. For experimental group II, electric circuit mental models and water circuit analogy were applied. For control group, traditional teaching method was used. The results indicate statistically significant differences between two experimental groups and the control group. The use of electric circuit mental models and water circuit analogy as teaching aids were more effective in electricity concepts than traditional teaching method

Iron oxide/hydroxide-nitrogen doped graphene-like visible-light active photocatalytic layers for antibiotics removal from wastewater

Hybrid layers consisting of Fe oxide, Fe hydroxide, and nitrogen doped graphene-like platelets have been synthesized by an eco-friendly laser-based method for photocatalytic applications. The complex composite layers show high photodecomposition efficiency towards degradation of antibiotic molecules under visible light irradiation. The photodecomposition efficiency was investigated as a function of relative concentrations of base materials, Fe oxide nanoparticles and graphene oxide platelets used for the preparation of target dispersions submitted to laser irradiation. Although reference pure Fe oxide/Fe hydroxide layers have high absorption in the visible spectral region, their photodecomposition efficiency is negligible under the same irradiation conditions. The high photocatalytic decomposition efficiency of the nanohybrid layer, up to 80% of the initial antibiotic molecules was assigned to synergistic effects between the constituent materials, efficient separation of the electron-hole pairs generated by visible light irradiation on the surface of Fe oxide and Fe hydroxide nanoparticles, in the presence of conducting graphene-like platelets. Nitrogen doped graphene-like platelets contribute also to the generation of electron-hole pairs under visible light irradiation, as demonstrated by the photocatalytic activity of pure, reference nitrogen doped graphene-like layers. The results also showed that adsorption processes do not contribute significantly to the removal of antibiotic molecules from the test solutions. The decrease of the antibiotic concentration under visible light irradiation was assigned primarily to photocatalytic decomposition mechanisms.The authors are grateful for the financial support of the Spanish Ministry of Science and Innovation MCIN/AEI/https://doi.org/10.13039/501100011033 under the project PID2020-116612RB-C31, Generalitat de Catalunya, AGAUR through the projects 2017 SGR 1086 and 2017 SGR 1771, and the Romanian Ministry of Education and Scientific Research, UEFISCDI under the contract PN-III-P4-ID-PCE-2020-2024. ICMAB acknowledges the financial support from MCIN/AEI/https://doi.org/10.13039/501100011033, through the Severo Ochoa FUNFUTURE grant (CEX2019-000917-S).With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000917-S).Peer reviewe

Circuit Modeling on Polyaniline FunctionalizedNanowire-Templated Micro-InterdigitalCapacitors for pH Sensing

This study presents an improved alternative current (ac) circuit modeling of a highly sensitive capacitive pH-sensing element based on polyaniline (PANI) functionalized nanowire-templated micro-interdigited electrodes (NWs μIDEs). While electrical resonance measurements deal with a total equivalent capacity, comparative investigations show a good agreement with the fitting parameters of the corresponding model. A physical interpretation of the model is discussed to help in understanding the detection mechanism and a possible methodology to be used for further integration of the subsequent device is suggested

Biocomposite Materials Derived from <i>Andropogon halepensis</i>: Eco-Design and Biophysical Evaluation

This research work presents a “green” strategy of weed valorization for developing silver nanoparticles (AgNPs) with promising interesting applications. Two types of AgNPs were phyto-synthesized using an aqueous leaf extract of the weed Andropogon halepensis L. Phyto-manufacturing of AgNPs was achieved by two bio-reactions, in which the volume ratio of (phyto-extract)/(silver salt solution) was varied. The size and physical stability of Andropogon—AgNPs were evaluated by means of DLS and zeta potential measurements, respectively. The phyto-developed nanoparticles presented good free radicals-scavenging properties (investigated via a chemiluminescence technique) and also urease inhibitory activity (evaluated using the conductometric method). Andropogon—AgNPs could be promising candidates for various bio-applications, such as acting as an antioxidant coating for the development of multifunctional materials. Thus, the Andropogon-derived samples were used to treat spider silk from the spider Pholcus phalangioides, and then, the obtained “green” materials were characterized by spectral (UV-Vis absorption, FTIR ATR, and EDX) and morphological (SEM) analyses. These results could be exploited to design novel bioactive materials with applications in the biomedical field

Nanowires and nanostructures fabrication using template methods: a step forward to real devices combining electrochemical synthesis with lithographic techniques

One of the great challenges of today is to find reliable techniques for the fabrication of nanomaterials and nanostructures. Methods based on template synthesis and on self organization are the most promising due to their easiness and low cost. This paper focuses on the electrochemical synthesis of nanowires and nanostructures using nanoporous host materials such as supported anodic aluminum considering it as a key template for nanowires based devices. New ways are opened for applications by combining such template synthesis methods with nanolithographic techniques

Unidirectional Magnetic Anisotropy in Dense Vertically-Standing Arrays of Passivated Nickel Nanotubes

We report the facile and low-cost preparation as well as detailed characterization of dense arrays of passivated ferromagnetic nickel (Ni) nanotubes (NTs) vertically-supported onto solid Au-coated Si substrates. The proposed fabrication method relies on electrochemical synthesis within the nanopores of a supported anodic aluminum oxide (AAO) template and allows for fine tuning of the NTs ferromagnetic walls just by changing the cathodic reduction potential during the nanostructures’ electrochemical growth. Subsequently, the experimental platform allowed further passivation of the Ni NTs with the formation of ultra-thin antiferromagnetic layers of nickel oxide (NiO). Using adequately adapted magnetic measurements, we afterwards demonstrated that the thickness of the NT walls and of the thin antiferromagneticNiO layer, strongly influences the magnetic behavior of the dense array of exchange-coupled Ni/NiO NTs. The specific magnetic properties of these hybrid ferromagnetic/antiferromagnetic nanosystems were then correlated with the morpho-structural and geometrical parameters of the NTs, as well as ultimately strengthened by additionally-implemented micromagnetic simulations. The effect of the unidirectional anisotropy strongly amplified by the cylindrical geometry of the ferromagnetic/antiferromagnetic interfaces has been investigated with the magnetic field applied both parallel and perpendicular to the NTs axis