Journal of applied research and technology

http://www.scielo.org.mx/scielo.php?script=sci_issues&pid=1665-6423&lng=pt&nrm=iso

List of Papers (Total 183)

Math puzzles, powerful ideas, algorithms and computers in teaching problem-solving

With the current interest in teaching problem-solving, it is important that the example problems that are presented to students have important educational value. Many mathematical puzzles, while requiring little specific background to be posed and remembered, are paradigms of important practical problems. If the teacher chooses the right puzzles, he/she not only will have...

Measuring system for amperometric chemical sensors using the three-electrode technique for field application

A portable and low cost measuring system for amperometric chemical sensors using the three-electrode technique was developed. This technique allows chemical sensors to work with currents higher than ten microamperes. The system was based on a potentiostat operation, completed with an I-V converter and signal conditioning circuits. The instrument was evaluated comparing...

Optimization on RF devices design applied in wireless communications

Third generation (3G) cellular mobile communications demands very strict requirements on transreceptor devices design, in mobile terminal or base station [1]. Particularly, in mobile terminal, design requirements of power amplifier indicate the next parameters: High linearity (<-42dBc), low distortion (-42dBc), compression level of 1 dB, power gain (>20dB), maximum output power...

Applying the logo environment: learning, doing and discovering through computerized learning projects

In this paper the Logo environment is applied to several original computerized learning projects, each of a very different nature: one for learning geometry generating numerous instances for verifying the results of a little known theorem of plane geometry, a second for learning the basics of the physical foundations of music through the construction, using the keyboard of the...

Digital blood pressure monitor

In this work we present a blood pressure monitor which measures both the high blood pressure (systolic pressure), and the low blood pressure (diastolic pressure). It is a semiautomatic meter because the inflation of the occlusive cuff is carried out in a manual way. The transducer used is a piezoresistive silicon pressure sensor integrated on chip which provides a proportional...

Hearing Aid. measurement of electroacoustical characteristics

In this work we show the results obtained from several measurements, on hearing aid (HA) prototype carried out at the Acoustic Laboratory of the Centro de Ciencias Aplicadas y Desarrollo Tecnológico (CCADET) at the Universidad Nacional Autónoma de México (UNAM). The hearing aid has been developed at the Electronics Laboratory of the same Center. All the electroacoustic...

Electronic device to improve the efficiency of extracorporeal lithotripters

The design and construction of autonomous electronic instrumentation to generate fast high voltage discharges (6 to 10 kV) on a piezoelectric crystal array, in order to produce underwater shock waves, is described. If properly focused, hundreds of these shock waves are capable of destroying renal and ureteral calculi. This clinical treatment, developed more than 20 years ago, is...

CNC machine tools for low cost micro devices manufacturing

A new technology for production of low-cost micromechanical devices is proposed. This technology is based on concepts already known in conventional mechanics, used to produce a number of equipment of smaller sizes generation after generation. It is necessary to adapt each generation of equipment to the changes in physical behavior due to the decreasing scale. This technology is...

Innovation rate of change measurement part 1: Information Technology (IT)

It is possible to characterize the different stages of history according the type of technology available. The last fifty years of human history have been referred to as "The Information Age" because of the great advancements and innovations of technology in electronics, computers and communications. The first part of this work presents a method based on the generation and...

A wearable neural interface for real time translation of Spanish Deaf Sign Language to voice and writing

This paper describes a work related to the design and implementation of a communication tool for persons with speech and hearing disabilities. This tool provides to the user a Human-Computer interface capable of the capture and recognition of gestures belonging to the Mexican Spanish Sign Alphabet. To capture the manual expressions, a data-glove constructed to sense the position...

Implementation of real time autocorrelation method employing the DS87C550 microcontroller

In this work, the implementation of Real Time Autocorrelation method proposed by Takeuchi and Hogaki, is exposed. The purpose is to obtain the frequency of the fetal cardiac beats, originated from a Fetal Detector, using a wide-benefits DS87C550 microcontroller. The value of frequency is showed in a LCD. The autocorrelation algorithm was simulated in a PC to know its dynamic...

Performance of a MFS-based mosfet for low temperature applications

A split-drain MAGFET has been designed for detecting magnetic fields at very low temperature. In this design a key parameter is the Hall angle, which indicates the current line deviation due to the Lorentz force acting on the charge carriers. It is well known that reducing the work temperature the carrier mobility increases, therefore an increase in carrier deflection is expected...

Performance analysis of S-Aloha used as a random acces channel on mobile communications

This paper evaluates the effects of Rayleigh fading, shadowing, and spatial distribution of the Mobile Terminals (MTs) on the operating performance of Slotted Aloha (S-Aloha) used as a Random Access Channel (RACH). This paper also evaluates the capture probability in a channel exhibiting Rayleigh fading, shadowing, and the effect of spatial distribution of the MTs. In addition...

Object oriented software for micro work piece recognition in microassembly

The aim of this article is to describe object oriented software for the automatic micro work piece handling system. The general task of this system is the recognition of work pieces with neural classifier and detection of their positions. Other important functions of the system are work piece styles database administration, work piece database administration for neural classifier...

Analysis of a transport network based on georeference system and multicommodity network flow

The methodology used for the prediction of trips through the allocation of these according to the origin-destination (OD) survey, constitutes a traditional methodology to cover the demand of existing transport between the zones of analysis. When the transportation system fulfills the characteristics of a network (topology, routed arcs, nodes with commodity supply and demand, etc...

Technological support for ecology

Tele-detection offers great possibilities for the accomplishment of progress in the knowledge of Nature. However, all expected benefits have not yet been obtained since improvement in matters of data space, spectral and temporal resolution still need to be made. In addition, greater scientific rigor in the interpretation of the results obtained is needed, attempting not to draw...

A Silicon Magnetic-Field Sensor: Low-Temperature Performance Evaluation

A Si magnetic field-sensitive split-drain MOSFET has been used to study and analyze the effects of a magnetic field on the charge carrier conduction at liquid-nitrogen temperature. In magnetic field sensors (MFS), a key parameter is the Hall angle, which indicates the current line deviation due to the Lorentz force acting on the charge carriers. If temperature is lowered, the...