Spatial and temporal dynamics of Belousov-Zhabotinsky reaction: A STEM approach

An integrative methodology for teaching science is proposed through the STEM methodology (Science-Technology-EngineeringMathematics).The STEM methodology provides students the opportunity to combine knowledge in an interdisciplinary and collaborative manner, allowing the development of creative and systemic thinking. As a model we propose the experimental reproduction of the Belousov-Zhabotinsky reaction (BZ), which is the standard prototype of non-linear chemistry, in addition we used the Python V2.7 programming software and the Jupyter platform for the computational reproduction of the BZ reaction. The STEM methodology could help the development of new competences for students, that is, it will provide them with tools to solve complex current problems that require of the interdisciplinarity

MODEL DAN SIMULASI PERBANDINGAN PROTOTYPE RANGKAIAN DIGITAL HALF ADDER ALU STANDAR DENGAN INOVASI RANGKAIAN DIGITAL HALF ADDER ALU

- This research was conducted to model and simulate the Half Adder system. This system is designed by analyzing the descriptive method, and the comparative method. After analysis, modeling is done with UML (Unified Modeling Language) and hardware design based on microcontroller can be programmed using CodeVisionAVR-C software. The results of this study are a standard prototype Half ALU ALTER Adder system that uses XOR, AND, OR gates with ALU Half Adder system innovation using NAND and NOR gates.Keywords - Half Adder, Prototype, XOR, AND, OR, NAND, NOR

Composite resistor standard for calibration of measuring transducers in laboratory conditions

Calibration of measuring transducers for precision measurement is done by measuring voltage drop at the resistor standard, produced by output dc current proportional to the input measured value. Resistance fluctuations due to the temperature coefficient of the resistor standard are minor, thanks to the stable temperature conditions in laboratory environment. This fact brings the need to calculate the effect of resistor self-heating on its resistance. This thermal effect, produced by the flow of current through the resistor, is often disregarded. For the precise measurements this can be a significant source of error and must be quantified. This paper describes mathematical model of measurement error, resistor self-heating coefficient is defined, as it?s not usually given in product datasheets. The effect on measurement results is given in detail. Composite resistor standard prototype is described, made from off-the-shelf mass produced components, calculated and hand selected to cancel the self-heating coefficient effects. The prototype is compared to the existing commercially available high performance resistor standard.

ENCEPHALITIS IN EXPERIMENTAL COXSACKIE B-3 INFECTION

A study has been made of the vulnerability of various parts of the brain in experimental Coxsackie B-3 virus infection. The standard prototype Coxsackie B-3 virus and a stock of inbred albino mice have been used for this purpose. The sites of greatest susceptibility have been precisely defined by thorough examinations of the whole brain and it has been observed that in 7- to 12-day-old mice the lesions are confined to sensory centers.Furthermore, observations have been made upon the effects of various factors such as the age at the time of inoculation, the state of myelination in different parts of the brain, and the route of inoculation. The complete resistance of the cerebellum to damage in spite of multiplication of virus in this site is of considerable interest.In the past little attention has been paid to the anatomical distribution of the brain lesions caused by the Coxsackie group B virus. It would seem to be profitable to direct attention to the features of the experimental disease in view of our lack of basic information regarding many non-fatal illnesses which affect the brain.