arXiv subjects

Pablo Diniz Batista

Publications and source records attributed to Pablo Diniz Batista.

5 recordsLinked to original sources

arXiv2023

Experimental apparatus for non-contact resistivity measurements of the rock core plug based on magnetic induction

A new apparatus has been developed to measure the conductivity of rock samples. The probe, which consists of multi-coil transmitters and receivers doesn't require physical contact with the samples. The measurement is based on the induction principle. The measurement system is validated by using saline solutions and water-saturated sands of known conductivity. This work presents details of the development of a system of magnetic resistivity measurements by magnetic induction for petrophysical applications. The first application consists of measuring the resistivity of the core plug which is 0.038 m in diameter. Currently the system is operating properly at a frequency of 50 kHz with a current of up to 500 mA at 20 °C. During the study two types of samples were investigated: aqueous solutions with conductivities between 1 to 100 mS/cm and rocks. Several tests were carried out with the objective of investigating the performance of the instrument, such as the experiment to obtain sensitivity for the measurement system as a function of the current applied to the transmitter coil.

cond-mat.mtrl-sci↗

arXiv2016

Web of Science: showing a bug today that can mislead scientific research output's prediction

As it happened in all domains of human activities, economic issues and the increase of people working in scientific research have altered the way scientific production is evaluated so as the objectives of performing the evaluation. Introduced in 2005 by J. E. Hirsch as an indicator able to measure individual scientific output not only in terms of quantity, but also in terms of quality, h index has spread throughout the world. In 2007, Hirsch proposed its adoption also as the best to predict future scientific achievement and, consequently, a useful guide for investments in research and for institutions when hiring members for their scientific staff. Since then, several authors have also been using the Thomson ISI Web of Science database to develop their proposals for evaluating research output. Here, using a software we have developed, we analyse more than 100 thousand articles and show that a subtle flaw in Web of Science can inflate the results of info collected, therefore compromising the exactness and, consequently, the effectiveness of Hirsch's proposal and its variations.

physics.soc-ph↗

arXiv2013

An embedded measurement system for electrical characterization of EGFET as pH sensor

This work presents the development of an electronic system for the electrical characterization of pH sensors based on the extended gate field effect transistor (EGFET). We designed an electronic circuit with a microcontroller (PIC15F14K50) as the main component in order to provide two programmable outputs voltage as well as circuits to measure electric current and voltages. The instrument performance analyze was carried out using a glass electrode as a sensitive membrane for investigating the EGFET operation as pH sensor. The results show that the system is an alternative to commercial equipment for the electrical characterization of sensors based on field effect devices. In addition, some of the key features expected of this electronic module are: low cost, flexibility, portability and communication with a personal computer using a USB port.

physics.ins-det↗

arXiv2005

An index to quantify an individual's scientific research valid across disciplines

The number h of papers with at least h citations has been proposed to evaluate individual's scientific research production. This index is robust in several ways but yet strongly dependent on the research field. We propose a complementary index hI = h^2/N_t, with N_t being the total number of authors in the considered h papers. A researcher with index hI has hI papers with at least hI citation if he/she had published alone. We have obtained the rank plots of h and hI for four Brazilian scientific communities. Contrasting to the h-index curve, the hI index present a perfect data collapse into a unique allowing comparison among different research areas.

physics.soc-ph↗

arXiv2005

Universal Behavior of a Research Productivity Index

Indexes that account for good representations of an individual's productivity are theme of major importance for the evaluation and comparison among researchers. Recently, a new index was proposed combining productivity with impact such that a researcher with index h has h papers with at least h citations. A drawback of this is the sensitivity to the research field. Here we propose a new index (hI) that accounts for the coauthorship effect. The statistics of h and hI are presented for Brazilian research. We have found a universal curve for different disciplines, allowing a comparison among scientists of different research areas.

physics.soc-ph↗