Los dispositivos electrónicos que han sido diseñados para ser instalados en el vehículo pueden ser sometidos a pruebas necesarias para obtener una certificación o aprobación mínima requerida para ser ...instalada en el sistema eléctrico del automóvil. Con el uso de un equipo normado el cual permite generar condiciones eléctricas a un dispositivo electrónico, se han obtenido diferentes resultados ante el comportamiento eléctrico que se puede encontrar especialmente en el vehículo; condiciones tales como: caídas momentáneas de tensión, sobretensiones e inversiones de tensión de voltaje, considerando incluso someter los dispositivos a las fuertes condiciones eléctricas del sistema automotriz cuando se produce el arranque del motor. Con este análisis se obtiene resultados del comportamiento entre dos dispositivos electrónicos y de tal manera determinar mediante la validación de cada uno, si las características del diseño o aspectos de programación pueden influir en el resultado de cada prueba. Esto nos permite considerar varios aspectos ante el diseño del dispositivo y de esta manera lograr conseguir un óptimo funcionamiento; siendo esto reflejado en obtener una certificación.
Many large furnaces used for production of ferroalloys are operated using three-phase alternating current. In such furnaces, there are significant skin and proximity effects caused by induction ...effects in, and between, the electrodes. Moreover, there may be high currents induced in the furnace steel shell. This causes additional proximity effects between the currents in the electrodes and alloy, and the induced currents in the lining and shell. A numerical study of such effects in realistic 3D geometries of ferromanganese and ferrosilicon furnaces is presented. The models are used to estimate the induced currents in the steel shell as well as accurate alternating current distributions in the material layers within the furnace. Also, the active and reactive power densities within the furnace are studied. The results show that there are strong skin and proximity effects in the conductive material layers within the furnace. Both the electrode proximity effects and the proximity effects caused by the steel shell are computed. The latter can be significant, and should be included when high accuracy is required.
The voltage problem generally exists in the high-speed train (HST) and may influence the train's normal operation. It is important to analyze the voltage of train body (TB) for safety protection. ...Taking China railways highspeed 380CL-type train as an example, by means of electromagnetic transients program, this paper proposes a systematic train impedance modeling scheme that is only aimed at low-frequency electrical conditions. Based on the effective analysis regarding the influence factors of TB voltages, this scheme is elaborated. At first, through investigation, only the modeling of impedance parameters of TB and rail is involved, and the measured operation grounding currents are selected as the external sources of model. Next, the model impedance parameters are determined by theoretical calculations or experimental measurements for establishing the final model. Last, based on three different HST operation conditions, experiments are implemented in the Chinese Nanjing electric multiple unit station. The effectiveness of modeling scheme is demonstrated by the comparisons of many model simulations and experimental measurement results, which not only indicates that the assumptions and simplifications in modeling are reasonable, but also illustrates that the scheme can assess the TB voltages for different low-frequency electrical conditions and different HST types.
The electromagnetic-field distribution in a refined-slag layer is simulated so as to refine the electrical operating conditions in ladle–furnace units. A mathematical model is derived for the ...electric field strength in the slag layer. The dependence of the resistivity of metal slags on their basicity and the melt temperature is obtained. A difference scheme is proposed for the solution of the differential equation describing the electromagnetic-field distribution. The differential equation is solved by Picard successive approximation. Sample electromagnetic-field distributions in the slag layer at different heights from the metal meniscus are presented. The results of mathematical simulation are in good agreement with physical modeling.
Electrochemotherapy (ECT) or electrical impulse chemotherapy, proposed by Okino and Mohri and Mir et al., is a new technique that enhances the antitumor effect of various anticancer agents by ...delivering high-voltage electrical impulses to tumors. Recently, several reports have described the effectiveness of ECT against tumor cell lines. However, few experimental studies have evaluated the optimum electrical conditions for ECT. We designed this study to determine the optimum electrical conditions for ECT against rat squamous cell carcinoma in vitro and in vivo. SCC158 cells, a rat squamous cell carcinoma cell line, were cultured in Dulbecco's MEM with several concentrations of bleomycin (BLM) for 72 hours. The BLM concentration that inhibited cell growth by 50%(BLM-IC50) was determined by MTT Assay. Tumor cells in the media containing BLM-IC50×10-1, BLM-IC50×10-2, or BLM-IC50×10-3 recieved electrical pulses (200-1400V/cm, 0.1msec, 1-8 pulses) and were sequentially recultured for 72 hours. The surviving fraction of tumor cells was analyzed. SCC158 cells were transplated into the tongue of Fischer rats. The rats recieved electrical pulses (125-1200V/cm, 0.1msec, 8 pulses) 30min after the administration of BLM. The antitumor effect of ECT on these tumors and damage to the surrounding normal tissue were then evaluated histologically. The anticancer effect of ECT appeared when the voltage was more than 600V/cm. Futhermore, ECT of 1000-1200V/cm enabled the BLM concentration to be reduced to as low as 1/100 the BLM-IC50 to obtain a similar anticancer effect in vitro. In addition, the anticancer effect of ECT was strongest when the voltage was 1000V/cm or more; however, the surrounding normal tissue within the electrical field was seriously damaged in vivo. In conclusion, ECT is expected to be useful in the treatment of human oral cancers, and the optimum voltage is considered to be 1000V/cm or more. It is hoped that problems related to damage to normal tissue will be resolved by future investigations.
In order to find the electrical conditions for operating high-pressure sodium lamps with a constant correlated color temperature to get high color rendering from lamps of the same type having ...different correlated color temperatures, we conducted a set of experiments. We operated 150W lamps under various electrical conditions to determine the relationship between the correlated color temperature and the electric properties. Based on the results, we derived the following formula: Tcp=a·W1a+b· V1a+c, where Tcp is the correlated color temperature, W1a is the lamp power, Via is the lamp voltage, and a, b, and c are constants. This formula gives the electrical conditions of W1a and V1a for a specific value of Tcp. The same formula is also applicable to lamps of other wattages by changing the values of the constants a, b, and c. If the correlated color temperature of the lamp is limited to±150K by controlling these electrical conditions, the deviation of the lamp from the black body locus is preferable for vision. In the same manner, we derived Tcp=d· V1a+e· I1a+f, where Tcp is the correlated color temperature, V1a is the lamp voltage, I1a is the lamp current, and d, e, and f are constants. The sensing circuits for a specific value of Tcp can be the simple sensing circuits of V1a and I1a.
An interface crack between dissimilar one-dimensional hexagonal quasicrystals with piezoelectric effect under anti-plane shear and in-plane electric loadings is considered. Mixed boundary conditions ...at the crack faces are studied. Using special representations of field variables via sectionally analytic vector-functions, a homogeneous combined Dirichlet–Riemann boundary value problem and a Hilbert problem are formulated. Exact analytical solutions of both these problems are obtained, and analytical expressions for the phonon and phason stresses and the electric field as well as for the derivative jumps of the phonon and phason displacements and also the electrical displacement jump along the bimaterial interface are derived. The field intensity factors are determined as well. The dependencies of the mentioned values on the magnitude and direction of the external electric loading and different ratios of electrically conductive and electrically permeable crack face zone lengths are demonstrated in graph and table forms.
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