The international trade, the environmental protection and the science, today, cannot be able to exist without reliable measurements. Nowadays, any results of measurement of a physical or chemical quantity should be accompanied for any quantitative indication of the quality of this data, in order to be able to evaluate its reliability. Thus, an easy concept known and with wide acceptance that could characterize the quality of the result of a measurement is expressed by its uncertainty. In this work, we will present the application of the ISO GUM 95 for estimating uncertainty in the following tests: sulfur and flash point in diesel fuel. This research includes the development of a software based on Delphi version 6.0 to calculate the possible sources of uncertainty associated to the measurement used in both process and an estimation of their value, either by statistical methods (Type A) or by other means (Type B). Later on the individual components are combined to calculate the standard and expanded uncertainty for the whole process. The program developed aimed reducing the time spent in figuring out the main sources of uncertainty, moreover, facilitating the obtainment of the uncertainty result. To visualize the most relevant factor in the uncertainty measurement, the program provides a graphic showing the uncertainty contributions and enables the calculation of final uncertainty combined by the relative method, based on Eurachem/CITAC Guide, allowing the graphic comparison among the different methods in calculating uncertainty in measurement.

In different areas of science and engineering are used different indirect measurement procedures that lead to obtaining the quantity desired. In this paper is described the considerations about indirect measurement system (IMS). Is realized the analysis between direct measurement and indirect measurement, presenting the limitations of the estimator. The IMS are classified under the methodological point of view. Practical considerations for design of IMS in dynamic system are specified, as clock cycle, time of hardware execution and software, size of the memory of data and program, represented for quality; system modelling; error estimations and uncertainty in indirect measurement.

Fiber optic optical time domain reflectometry (OTDR) sensors are suitable to apply the distributed measurement by multiplexing configuration. OTDR sensor system with displacement sensors has been developed to monitor slope stability in soil layers. The displacement was determined from the difference between the reflected signal of the sensing optical connector and the signal of the reference optical connector. Laboratory tests indicate that displacements can be measured with the resolution of several mm and the maximum measurable displacement is about 10 cm, which is enough to apply for the monitoring of soil movements.

Emissions monitoring of volatile organic compounds (VOC) from industrial facilities is complex for both economical, computational and practical reasons. A new wide areas monitoring approach based on "few sensors" wireless network supported by a predictive learning algorithm and an air modeling software can obtain both local and wide VOC estimation.

The paper presents the implementation of a low cost, small size portable measuring system based on a personal digital assistant (PDA) for indoor air quality monitoring. The virtual system is based on a compact flash data acquisition board (CF-DAQ), plugged-in the PDA, that provides a set of analogue inputs used to read the voltages associated with temperature, humidity and broadband air quality sensors. The acquired voltages corresponding to the air conditions of individual rooms or vehicle cabins under observation are processed at the PDA level using the LabVIEW software that assures the voltage to air quantity conversion (VAQc) using techniques such as look-up tables and polynomial or neural network inverse modelling. A comparison between the above mentioned conversion techniques are considered. Information from the sensors can also be recorded in the PDA memory (quite limited) or in the building room air quality monitoring in a personal computer that are Wi-Fi connected to the PDA.