ABSTRACT
The paper deals with a brief overview of magnetoelastic sensors and magnetoelastic sensors used in general for sensing bending forces, either directly or sensing bent structures, and defines the current state of the art. Bulk magnetoelastic force sensors are usually manufactured from transformer sheets or amorphous alloys. In praxis, usually, a compressive force is sensed by bulk magnetoelastic sensors; however, in this paper, the sensor is used for the measurement of bending forces, one reason being that the effect of such forces is easily experimentally tested, whereas compressive forces acting on a single sheet make buckling prevention a challenge. The measurement of the material characteristics that served as inputs into a FEM simulation model of the sensor is presented and described. The used material was considered to be mechanically and magnetically isotropic and magnetically nonlinear, even though the real sheet showed anisotropic behavior to some degree. A sinusoidal magnetizing current waveform was used in the experimental part of this paper, which was created by a current source. The effects of various frequencies, amplitudes, and sensor geometries were tested. The experimental part of this paper studies the sensors' RMS voltage changes to different loadings that bend the sheet out of its plane. The output voltage was the induced voltage in the secondary coil and was further analyzed to compute the linearity and sensitivity of the sensor at the specific current characteristic. It was found that for the given material, the most favorable operating conditions are obtained with higher frequency signals and higher excitation current amplitudes. The linearity of the sensor can be improved by placing the holes of the windings at different angles than 90° and by placing them further apart along the sheet's length. The current source was created by a simple op-amp voltage-to-current source controlled by a signal generator, which created a stable waveform. It was found that transformer sheet bending sensors with the dimensions described in this paper are suitable for the measurement of small forces in the range of up to 2 N for the shorter sensors and approximately 0.2 N for the longer sensors.
ABSTRACT
BACKGROUND: Coronavirus disease-2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is characterized by systemic inflammatory response syndrome and vasculopathy. SARS-CoV-2 associated mortality ranges from 2% to 6%. Liver dysfunction was observed in 14%-53% of COVID-19 cases, especially in moderate severe cases. However, no cases of spontaneous hepatic rupture in pregnant women with SARS-CoV-2 have been reported. CASE SUMMARY: A 32-year-old pregnant patient (gestational age: 32 wk + 4 d) without any remarkable medical history or long-term medication presented with epigastralgia. Infectious, non-infectious, and pregnancy-related hepatopathies were excluded. Sudden onset of right subcostal pain with D-dimer and liver enzyme elevation was followed by shock with thrombocytopenia. While performing an emergency cesarean section, hemoperitoneum was observed, and the patient delivered a stillbirth. A 6-cm liver rupture at the edges of segments V and VI had occurred, which was sutured and drained. SARS-CoV-2 positivity on reverse transcription-polymerase chain reaction was confirmed. Further revisions for intrahepatic hematoma with hemorrhagic shock and abdominal compartment syndrome were performed. Subsequently, the patient developed hemoptysis, which was treated using bronchoscopic therapy and non-invasive ventilation. Liver tissue biopsy revealed hemorrhagic foci and necrosis with an irregular centrilobular distribution. Antiphospholipid syndrome and autoimmune hepatitis were also ruled out. Fetal death was caused by acute intrauterine asphyxia. CONCLUSION: This case reveals that pregnant women with SARS-CoV-2 infection may be predisposed to liver parenchyma disease with liver rupture.
ABSTRACT
The article describes the implementation of IoT technology in the teaching of microprocessor technology. The method presented in the article combines the reality and virtualization of the microprocessor technology laboratory. A created IoT monitoring device monitors the students' microcontroller pins and sends the data to the server to which the teacher is connected via the control application. The teacher has the opportunity to monitor the development of tasks and student code of the program, where the functionality of these tasks can be verified. Thanks to the IoT remote laboratory implementation, students' tasks during the lesson were improved. As many as 53% (n = 8) of those students who could improve their results achieved an improvement of one or up to two tasks during class. Before the IoT remote laboratory application, up to 30% (n = 6) of students could not solve any task and only 25% (n = 5) solved two tasks (full number of tasks) during the class. Before implementation, 45% (n = 9) solved one problem. After applying the IoT remote laboratory, these numbers increased significantly and up to 50% (n = 10) of students solved the full number of tasks. In contrast, only 10% (n = 2) of students did not solve any task.
Subject(s)
Laboratories , Students , Humans , Monitoring, PhysiologicABSTRACT
An ever-increasing use of wireless devices over the last decades has forced scientists to clarify their impact on living systems. Since prenatal development is highly sensitive to numerous noxious agents, including radiation, we focused on the assessment of potential adverse effects of microwave radiation (MR) on testicular development. Pregnant Wistar albino rats (3 months old, weighing 282±8 g) were exposed to pulsed MR at a frequency of 2.45 GHz, mean power density of 2.8 mW/cm², and a specific absorption rate of 1.82 W/kg for 2 hours/day throughout pregnancy. Male offspring were no longer exposed to MR following birth. Samples of biological material were collected after reaching adulthood (75 days). In utero MR exposure caused degenerative changes in the testicular parenchyma of adult rats. The shape of the seminiferous tubules was irregular, germ cells were degenerated and often desquamated. The diameters of the seminiferous tubules and the height of the germinal epithelium were significantly decreased (both at ∗∗p<0.01), while the interstitial space was significantly increased (∗∗p<0.01) when compared to the controls. In the group of rats prenatally exposed to MR, the somatic and germ cells were rich in vacuoles and their organelles were often altered. Necrotizing cells were more frequent and empty spaces between Sertoli cells and germ cells were observed. The Leydig cells contained more lipid droplets. An increased Fluoro Jade - C and superoxide dismutase 2 positivity was detected in the rats exposed to MR. Our results confirmed adverse effects of MR on testicular development.
