As far back as the 1950s, Mercedes tried direct injection in a few production models, but the technology originally lost out to the less expensive indirect systems.
Because direct measurements of rock compressibility are time consuming and cost expensive, indirect measurements from other readily available experimental data are highly demanded.
Treatment is expensive; indirect costs are more so.
Indirect, and also less expensive.
Of the two systems, many favor the indirect, because it is less expensive.
The currently available detection methods are either indirect or time consuming and expensive.
But then Jupiter moves too far out of position, and alternate routes to Pluto are either much more expensive or much more indirect.
The objective is to develop an indirect method that avoids the potentially expensive direct solution of the problem.
Rare and elusive species living in low visibility environments, like many of the world's threatened tropical animals, are usually impossible to count directly and difficult or expensive to detect by indirect methods [1], [2].
Though mono-Si devices exhibit high efficiency and a dominant place in commercial market, setbacks such as expensive purification process, poor defect tolerance, indirect band-gap nature (less absorption coefficient) have made researchers seek for a better alternative.
