We present the structural and spectroscopy characterization of carbon nanotubes (CNTs) grown by the spray pyrolysis technique, using ferrocene as catalyzer and cyclohexanol as the carbon source, and synthetized in a temperature range of 750 to 1000°C. The structural morphology was observed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The spectroscopy response was obtained by UV-Vis and Raman spectroscopy. We observed morphological changes and found that the product yield seems to increase with temperature. The optical characterization corroborated the presence of n–π∗ transitions and Van Hove singularities as result of possible electrical conductivity changes.

In this paper we present the didactic experience of building a low-cost robot composed of sensors, actuators, general electronics and already available frameworks. The control of the robot is through the usage of commercialOpen Sourceplatforms asArduino;and theRaspberry Pi.The experience ranges from general conceptualization, mechanical, electric and electronic design, microcontroller programming and communications.

The wave equation is a direct but a complex approach to solve analytically for the Chladni figures, mainly because of the complications that non-smooth and open boundary conditions impose. In this paper, we present an alternate solution model based on the principle of Huygens-Fresnel and on the ideas of Bohr for the hydrogen atom. The proposed model has been implemented numerically and compared, with good agreement, to our own experimental results for the case of a thin homogenous circular plate with open boundaries.

We have performed a comparative study of electrical properties between pristine and nitrogen doped (at low concentration) single wall carbon nanotubes (SWNTs), for three zig-zag cases: (6,0), (8,0) and (9,0). The results were obtained through the Density Functional Theory (DFT) with the Generalized Gradient Approximation (GGA) in the relaxed Cî¸C bond length for the long-wavelength limit. The stability of the structures was determined by calculating total energies for the pristine and the N-doped structures. From the calculations of the energy loss function, we probed plasmon peak positions for the proposed quiralities. Keywords: DFT, Carbon nanotubes, Electrical propertie

Carbon nanotube (CNT)-based hydrogels continue to present a persistent challenge of material comparability, as systems that appear equivalent frequently generate different mechanical, electrical, and biological responses. Although experimental variability is frequently cited as the primary explanation, many discrepancies arise from comparing systems whose nanotubes differ structurally in ways that are rarely documented. Diameter distribution, defect density, residual catalyst content, and surface chemistry directly influence CNT dispersion, network integration, and interactions in hydrated polymer matrices. When these parameters are insufficiently reported, formulations that appear comparable may represent materially distinct systems. In this review, the CNT–hydrogel literature is reconsidered from the perspective of material comparability. Rather than focusing only on whether reported results agree across studies, this review evaluates whether sufficient structural and processing information is available to determine if the systems being compared are materially equivalent. Selected publications were analyzed using a reporting-based descriptor framework encompassing nanotube origin, structural characterization, dispersion, microstructure, transport behavior, and biological relationships. A consistent pattern emerges: reproducibility becomes more interpretable when nanotube identity and processing history are documented with sufficient resolution. This enables meaningful cross-study comparison without requiring strict protocol standardization.