Experimental study on the transmission of measurements by tolerance in SCADA systems

The study of the existing relationship between a measurement error and the time elapsed since that measurement was taken in the field, a period of time which we will call the datum age, will allow us to learn about its behavior in a supervisory control and data acquisition (SCADA) system. This study has allowed us to know that, in the case of electrical measurements, they quickly reach their maximum error value because of their age. Therefore, it is not necessary to send measurements to the control center at small intervals: it is possible to wait a given time without having a higher associated error. After getting these results, we have done an experimental study about electrical measurements, in which these measurements are sent to the control center only if they exceed a given percentage of the former measurement, what we call measurement tolerance. In this paper, it has been experimentally proved that this send-by-tolerance method significantly reduces the transmission channel load, so the system can benefit from this because the bandwidth can be reused by more remote units, as well as performance of the existing ones is improved.     

“In‐field” cell temperature evaluation in solar modules through time‐dependent open circuit voltage measurements

A method for the evaluation of p–n junction cell temperature in PV modules operating in the maximum power point (MPP) mode has been proposed. The method does not require specialized equipment and (for the concentrator modules) the data on the open circuit (OC) voltage temperature coefficients measured under pulse illumination. It consists of measuring several open circuit voltage magnitudes together with temperature measurements on the external module surface near one of the cells. In this procedure, a fast transition from MPP to OC operational mode is carried out, during which a time‐dependent voltage measurement is carried out with the help of a memory oscilloscope. A “reference” OC voltage magnitude in a “cold” module (a condition, as if the cells are kept at ambient temperature) is obtained by calculations, so that there is no necessity in a fast mechanical shuttering of the module aperture area. In the case of the concentrator modules, the module OC voltage temperature coefficient can be measured, if heat sinking process is artificially modified during outdoor measurements. Copyright © 2015 John Wiley & Sons, Ltd.     

The origin of the catalysis of hydrogen peroxide reduction by functionalized graphene surfaces: A density functional theory study

The adsorption of hydrogen peroxide on pristine and modified graphene sheets is studied by means of density functional theory calculations. The system considered involves perfect and defective layers, which can be pristine or functionalized with carboxyl groups.It is found that functionalization increases (in absolute value) the adsorption energy of hydrogen peroxide and improves the reduction reaction due to a favourable change in the properties of the defective layer. These changes are analyzed and mechanisms for the reduction reaction of hydrogen peroxide on the different surfaces are proposed. The associated energy barriers are calculated by means of state-of-the-art calculation methods.     

Synthesis of Fatty Acid Amides of Catechol Metabolites that Exhibit Antiobesity Properties

A series of fatty acid amides of 3,4‐methylenedioxymethamphetamine (MDMA) catechol metabolites were synthesized in order to evaluate their biological activities. Upon administration, all synthesized compounds resulted in negative modulation of food intake in rats. The most active compounds have affinity for the CB₁ receptor and/or PPAR‐α; part of their biological activity may be caused by these double interactions.     

Expert system for the integrated management of a power utility'scommunication system

In this paper we present a rule-based expert system applied to the fault diagnosis in the communication system of a power utility. The expert system is part of the system devoted to the management of a power utility's communication system, that we called NOMOS. NOMOS manages the communication systems of Sevillana de Electricidad and Union Electrica Fenosa (two major Spanish power utilities)     

Development of a PCR protocol to detect ochratoxin A producing moulds in food products

Ochratoxin A (OTA) is a mycotoxin produced by several Penicillium and Aspergillus species growing in food commodities. To prevent OTA in foods it is necessary to have rapid and specific methods for early detection of producing moulds regardless of species and genera. In this work a PCR method to detect ochratoxigenic moulds has been developed. For this purpose, 75 mould strains belonging to species usually reported in food products were used. Their OTA production was checked by micellar electrokinetic capillary electrophoresis (MECE) and high-pressure liquid chromatography-mass spectrometry (HPLC-MS). A specific amplicon of 459 bp was detected by using the designed PCR protocol only in the OTA producing strains. The detection limit of the developed PCR protocol was estimated for 25 pg of mould DNA from pure cultures and from about 10²–10⁴ cfu/g when it was evaluated directly on artificially inoculated food. Its functionality in naturally infected samples was also demonstrated. In conclusion, the developed PCR method could be used for detecting ochratoxigenic moulds in foods and consequently for monitoring these moulds in the HACCP programs.