Crude oil aggregation by microscopy and dynamic light scattering

This research is focused on establishing a methodology to evaluate the aggregation state of Mexican crude oil solutions from two different sources and SARA compositions, by using Dynamic Light Scattering (DLS). Different crude oil concentrations were established and monitored through time in order to determine their effects on the aggregation state. DLS results indicate that the aggregation state of the studied solutions is influenced by crude oil composition, specifically by the amount of resins. Particle size and elemental analysis of the aggregates were performed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX), respectively. Results from these techniques reveal particulated low-porosity smooth surfaces due to the presence of resin, as well as the determination of the characteristic elements found in asphaltenes. High-Resolution Transmission Electron Microscopy (HTEM) indicated the presence of asphaltene aggregates constituted by nanometric particles and asphaltene stacking as well as ultrafine nanocrystalline-oriented structures.     

Multi-agent location system in wireless networks

In this paper we propose a flexible Multi-Agent Architecture together with a methodology for indoor location which allows us to locate any mobile station (MS) such as a Laptop, Smartphone, Tablet or a robotic system in an indoor environment using wireless technology. Our technology is complementary to the GPS location finder as it allows us to locate a mobile system in a specific room on a specific floor using the Wi-Fi networks.The idea is that any MS will have an agent known at a Fuzzy Location Software Agent (FLSA) with a minimum capacity processing at its disposal which collects the power received at different Access Points distributed around the floor and establish its location on a plan of the floor of the building. In order to do so it will have to communicate with the Fuzzy Location Manager Software Agent (FLMSA). The FLMSAs are local agents that form part of the management infrastructure of the Wi-Fi network of the Organization.The FLMSA implements a location estimation methodology divided into three phases (measurement, calibration and estimation) for locating mobile stations (MS). Our solution is a fingerprint-based positioning system that overcomes the problem of the relative effect of doors and walls on signal strength and is independent of the network device manufacturer.In the measurement phase, our system collects received signal strength indicator (RSSI) measurements from multiple access points. In the calibration phase, our system uses these measurements in a normalization process to create a radio map, a database of RSS patterns. Unlike traditional radio map-based methods, our methodology normalizes RSS measurements collected at different locations on a floor. In the third phase, we use Fuzzy Controllers to locate an MS on the plan of the floor of a building.Experimental results demonstrate the accuracy of the proposed method. From these results it is clear that the system is highly likely to be able to locate an MS in a room or adjacent room.     

Application of near (NIR) infrared and mid (MIR) infrared spectroscopy as a rapid tool to classify extra virgin olive oil on the basis of fruity attribute intensity

A sensory analysis of 112 virgin olive oils was performed by a fully trained taste panel. The samples were divided in “defective” and “not defective” on the basis of their olfactory attributes. Then, the “not defective” samples were classified into “low”, “medium” and “high” according to the fruity aroma intensity perceived by assessors. All samples were also analysed by FT-NIR and FT-IR spectroscopy and processed by classification methods (LDA and SIMCA). The results showed that NIR and MIR spectroscopy coupled with statistical methods are an interesting technique compared with traditional sensory assessment in classifying olive oil samples on the basis of the fruity attribute. The prediction rate varied between 71.6% and 100%, as average value. The spectroscopic methods, combined with chemometric strategies, could represent a reliable, cheap and fast classification tool, able to draw a complete fingerprint of a food product, describing its intrinsic quality attributes, that include its sensory attributes.     

Effect of polypropylene morphology on thermal cis-trans isomerization and photofading of some azo dyes: A kinetic study

Five polypropylene films were prepared having different crystallinity and morphology, the latter having been modified by stretching. They were colored with azo dyes XC₆H₄N?NC₆H₄N(C₂H₅)₂ (where X?H, OCH₃, CN, and NO₂). The kinetics of the thermal cis-trans isomerization of these dyes has been studied in the range 21–41°C, much above the glass transition temperature of the polymer. The isomerization process was found to be strictly first-order; the kinetic parameter values have been correlated with the free volume extent in the amorphous regions of the matrix. Lightfastness of the dyes in the polymer matrices has been also investigated: It appeared to be more important for the unoriented samples with respect to the stretched ones and substantially independent on the crystalinity degree.     

Effect of poly(ethylene terephthalate) morphology on thermal cis-trans isomerization and photofading of some azo dyes: A kinetic study

Three poly(ethylene terephthalate) films were prepared having the same crystallinity but different morphology. They were colored with azo dyes XC₆H₄N = NC₆H₄N(C₂H₅)₂ (where X is H, OCH₃, CN, and COOC₂H₅). The kinetics of the thermal cis-trans isomerization of these dyes has been studied below the glass transition temperature in the range 25–56°C. The isomerization process was found to be the result of a multiplicity of first-order reactions. The kinetic parameters have been correlated with the order degree at molecular level of the polymer. Lightfastness of the dyes in the polymer matrices has been also investigated: it appeared to be in relation with the supermolecular structure of the film.     

Photochemical grafting of acrylated azo dyes onto polymeric surfaces,IV. Grafting of 4-(N-ethyl-N-2-acryloxyethyl)amino-4′-nitro-azobenzene onto cellulose

Photochemically induced grafting and graft-polymerization of 4-(N-ethyl-N-2-acryloxyethyl)amino-4′-nitro-azobenzene I , brought into contact in the solid state with cellulose by evaporation of solvent from monomer solutions, has been investigated kinetically at 30°C. Two constant rate periods were observed. The first one was interpreted on the basis of a self-sensitized grafting mechanism of monomeric or oligomeric species of I , photochemically initiated by hydrogen abstraction from the cellulose surface. The second one was explained as a self-sensitized photochemically induced graft-polymerization of I on the first grafted layer. Some particular features, such as concurrent photodegradation of the first grafted layer at low surface coverage, are discussed in the light of the proposed mechanism.     

Evaluation of freshness decay of minced beef stored in high-oxygen modified atmosphere packaged at different temperatures using NIR and MIR spectroscopy

Meat freshness has been monitored by various microbiological, chemical and sensorial indices. However, these methods are slow and not suited to automation. Infrared spectroscopy is one of the most convenient analytical tools which could be used to monitor the evolution of food quality. The aim of this work was to investigate the ability of both NIR (Near Infrared) and MIR (Mid Infrared) spectroscopy to follow meat freshness decay. The minced beef was packaged in high-oxygen modified atmosphere (30% CO₂ and 70% O₂) and stored at three temperatures. Spectra were collected by Fourier-Transformation (FT)-NIR and FT-IR instruments. PCA, applied to the data, was able to discriminate samples on the basis of storage time and temperature. The modelling of PC scores versus time allowed the setting of the time of initial freshness decay for the samples (6–7 days at 4.3 °C, 2–3 days at 8.1 °C and less than 1 day at 15.5 °C).     

Space-frequency linear dispersion codes for single carrier-frequency domain equalization

This letter addresses the application of Linear Dispersion Codes (LDC) in space and frequency domains in Single Carrier - Frequency Domain Equalization (SCFDE) systems. Space-Frequency (SF)-LDCs are more suitable than Space- Time (ST)-LDC in high mobility environments. However, the application of LDCs in space and frequency domains in SCFDE systems is not straightforward as in Orthogonal Frequency Division Multiplexing (OFDM) systems because in this case there is no direct access to subcarriers at the transmitter. This letter shows that it is possible to induce a target SF symbol dispersion in SCFDE by using a simple linear pre-coder and a conventional LDC that spreads the symbols in time and space domains according to specific ST dispersion matrices. The letter shows how to derive the ST dispersion matrices to be used at the transmitter as a function of the dispersion matrices describing the target SF dispersion. The presented procedure can be applied to both pure transmit diversity and pure multiplexing schemes, which are special cases of LDCs. Therefore, the proposed scheme provides a low complexity implementation of any dispersion in space and frequency over SCFDE systems, which alternatively would require the use of FFT/IFFT also at the transmitter side. The letter also shows a performance comparison of SF-LDCs and ST-LDCs in a typical propagation environment for future radio systems. The comparison confirms the suitability of using the dispersion in frequency rather than time for a wide range of coherence bandwidths.     

NIR and MIR spectroscopy as rapid methods to monitor red wine fermentation

Fifteen micro-fermentation trials were conducted during the 2008 vintage harvest in the Valtellina (Northern Italy) viticultural area. During fermentation, the spectra were achieved in the near and mid-infrared region by a FT-NIR spectrometer and a FT-IR spectrometer, respectively. Samples were also analysed by using chemical methods to evaluate sugars (glucose and fructose), alcohols (ethanol and glycerol) and phenolic compounds (total phenolics, total anthocyanins and total flavonoids). The pretreated spectral data were processed using principal component analysis. After feature selection by the algorithm SELECT, linear discriminant analysis (LDA) was applied to spectral data as a classification technique, to predict the fermentation stage from initial to final phase. Moreover, partial least square regression was used to predict sugar content, ethanol, glycerol and phenolic compounds simultaneously. LDA results, characterised by a high percentage of correct classification (87% and 100% as average value in prediction for NIR and MIR spectroscopy, respectively), showed that samples belonging to a particular fermentation step could be correctly classified. Good calibration models for the prediction of the main compositional changes during alcoholic fermentation were obtained with both FT-NIR and FT-IR, suggesting that either instruments could be used to evaluate online and simultaneously these compounds in red wine.