Nature's pH meter

The Youden pH Meter

Sørensen used a slide-wire potentiometer to make his pH measurements. Here a known potential is applied to counterbalance the potential of the hydrogen cell (i.e. the hydrogen electrode plus the counter electrode) and to reduce its current output to zero, at which point the value of the applied counter-potential is equal to that of the cell potential. Since the point of balance is indicated by...

pH Measurement with a fiber-optic tissue-pH monitor and a standard blood-pH meter.

Continuous monitoring of the pH of tissue with a glass electrode was initially introduced by Stamm et al. (1). Its potential value in monitoring the high-risk fetus during labor has been demonstrated in several studies (2-4). However, this technique has not been clinically accepted for routine use in labor, mostly because of problems with the application and sustained proper attachment of the r...

The Natures of Nonconfigurationality

Population, development, and human natures

At the dawn of this new millennium, the human enterprise is quickly becoming a globally unified one. Yet numerous obstacles and pitfalls remain in the path of a full and fair unification. A substantial fraction of the world’s population is well-off and increasingly connected through trade and communications systems. But an even larger fraction is struggling to make ends meet and is only sketchi...

Design and Development of Microcontroller Based Digital pH Meter

A Microcontroller based digital pH meter was designed and developed to measure the value of pH (acidity or alkalinity) for any type of solution. Two op-amps of high input impedance and low output impedance were used to design the pH meter: one is used as a buffer and the other as a summing amplifier. The output of the summing amplifier is connected to the microcontroller as an input. The pH val...