Journal of Experimental Techniques and Instrumentation

Analysis of the polarization states of light through the experimental determination of the Stokes Parameters

2022-01-05T09:45:43+00:00

Nowadays polarized light sources have various applications in optoelectronic devices, displays, stress tests on mechanical parts and even in studies of mineralogy. One of the main requirements is to determine the state of polarization (linear, circular, elliptical, or a superposition of them) of the light beam. In this work, we apply the emission ellipsometry technique to investigate the polarization states of different light sources. This technique is based on the theory of Stokes and the types of polarization are correlated to the Stokes parameters. The measurements were performed on beams of light from a polarized LASER, a polarized LASER passing through a quarter wave lag at ± 45 ° (circular polarization), a depolarized LED and the same LED with light reflected onto glass plate at various angles including the Brewster angle. The experimental setup is composed by an achromatic quarter wave plate, a linear polarizer and a photodetector. The results have presented a discrepancy of about 1% compared to the already known polarization of the light sources. Thus we have verified that the emission ellipsometry technique can be applied to determine the polarization state of light produced by sources in general.

Developing a low cost microcontrolled space probe prototype for thermology work

2022-01-05T09:45:29+00:00

Although the prototyping process is traditionally associated with engineering, nowadays, there are several projects in different areas being developed from microcontrolled systems. This work aims to describe how a prototype of a low-cost microcontrolled space probe has applicability to the area of Physics and Astronomy. The materials used to develop the prototype of the low cost microcontrolled probe were a simple ESP32 microcontroller board and a BME-280 temperature sensor. The method for developing the interlocution between the hardware structures and the components coupled in the simulated space probe was the C ++ programming language. Finally, based on the structures that make up the cart, which simulates a space probe through its components, it was possible to collect satisfactory data regarding the temperature and compare it with the environmental conditions provided by meteorological institutes.

Exploring Torricelli's theorem with Arduino

2022-01-05T09:45:14+00:00

We explore the dynamics of the water in a PVC pipe during the drain using two independent sensors simultaneously. We track the height of the water column and the discharge velocity of the water through the hole made in the lower part of the pipe. The ultrasonic distance sensor and the flow meter used as sensors were controlled by an Arduíno board. The acquired data follows the theoretical models but, with a coefficient of discharge smaller than 1.

Production of Complex Ceramic Films using domestic Inkjet Printers

2022-01-05T09:44:57+00:00

The production cost is one of the issues for some complex ceramics applications, like the superconducting oxides. The main properties of such materials, i.e., zero electrical resistivity and perfect diamagnetism, make them attractive for several applications, including energy storage. Thus, in this work, we focus on the production and structural characterization of BSCCO superconducting films using a domestic inkjet printer. The precursor solution was prepared following Pechini's method, and it was used, such as the ink. Then, an E-shape film was printed over a SiO₂ substrate. The results show that the sample produced with 12 depositions presented a superconducting transition at 81 K and a critical current density of 9.68 A/cm² at 78 K.

Desenvolvimento do projeto mecânico conceitual de uma ferramenta didática para roleteamento cilíndrico ou plano

2022-01-05T09:44:43+00:00

In recent decades, the burnishing operation has gained relevance as a method of surface treatment of mechanical components. Burnishing is commonly used after the machining process in order to improve surface properties and resistance to cyclic loading of mechanical components. This article describes the development of the conceptual mechanical design of a burnishing tool with didactic purposes through Fusion 360 CAD (Computer Aided Design) software. In the development of the project, the steps of research, understanding of the problem and calculations necessary for the execution of the project were addressed, with all the results raised, the dimensioning of the helical compression spring and the screws used in the 3D modeling of the rolling tool was carried out. The project aimed to develop a reliable teaching tool that presents an alternative in relation to commercial equipment that have systems that use high pressure pumps or compressed air cylinders that increase the costs of the process. The results showed that the proposed burnishing tools have the capacity to withstand a burnishing force of 880 N and a burnishing pressure of 38.92 MPa which presents the execution efficiency and applicability of the project when compared to commercial tools. In addition, the proposed project enables the construction and dissemination of the technology.

Interações químicas entre monômero e molécula molde em polímeros com impressão molecular, o EGDMA: 2-VP (4: 1) - estudo de caso MIP lumefantrina

2022-01-05T09:45:58+00:00

Molecularly Imprinted Polymers (MIP) are synthetic materials used as a tool to enhance the selectivity in different analytical approaches, such as solid-phase extraction, chromatography, and sensing devices. Knowing the mechanism involved in the interaction between the template and monomer is essential for a further successful application. However, studies on this topic are scarce. This work evaluates the involved mechanisms in the template-monomer interaction for a lumefantrine MIP system, an antimalarial drug. Field-emission gun scanning electron microscopy, thermal analysis, X-ray diffraction, and density functional theory were applied to determine the mechanism involved in two MIPs obtained in different conditions. A new parameter, named Molecularly Imprinting Factor (MIF), was proposed to evaluate the contribution of specific interactions in the sorption of the analyte by the MIP structure. MIF allows direct insights into specific binding, non-specific contributions, interaction nature, behavior predictability, system acid-base behavior, pre-screening pairs capability, and binding site affinities evaluation. Two interaction types were observed, covalent and non-covalent, when methacrylic acid and 2-vinyl pyridine were used as monomers, respectively. Therefore, the use of methacrylic acid formed a sorbent inappropriate for solid-phase extraction since the binding is not reversible. On the other hand, 2-vinyl pyridine-lumefantrine binding was reversible, and MIF = 0.59 (59.02% of specific site sorption) indicates that the predominant mechanism in the sorption is specific.