QUANTIFICATION OF BINARY MIXTURES OF COCAINE AND ADULTERANTS USING DISPERSIVE RAMAN AND FT-IR SPECTROSCOPY AND PRINCIPAL COMPONENT REGRESSION

Current forensic methods for detecting and identifying cocaine and its adulterants are destructive, so evidence cannot be re-analyzed. Vibrational techniques [Raman and Fourier transform infrared (FT-IR) spectroscopy] allow rapid, economical, nondestructive analysis. This work compares these techniques as methods for quantifying mixtures of cocaine (in the crack presentation) and adulterants. The aim is to provide a method to determine the amount of cocaine in crack rocks and to identify and quantify possible adulterants. A sample of crack was adulterated with benzocaine, caffeine, sodium carbonate, and lidocaine to create binary mixtures of concentrations of 20%, 40%, 60%, and 80%; pure samples of each adulterant and of crack were also examined. All samples were observed using dispersive Raman and attenuated total reflectance FT-IR spectroscopy. Quantitative analysis was performed based on principal component regression (PCR) applied to simulated and real spectra. The PCR model revealed that the Raman spectra yielded only minor measurement errors and the highest correlations using the PC2 spectral vector, which presented spectral features of cocaine. Among the mixtures, the best and worst results were obtained for caffeine and sodium carbonate, respectively. Dispersive Raman spectroscopy outperformed FT-IR in the quantitative determination of binary mixtures of cocaine and adulterants.     

Binary integer programming formulations for scheduling in market-driven foundries

This paper describes the development and solution of binary integer formulations for production scheduling problems in market-driven foundries. This industrial sector is comprised of small and mid-sized companies with little or no automation, working with diversified production, involving several different metal alloy specifications in small tailor-made product lots. The characteristics and constraints involved in a typical production environment at these industries challenge the formulation of mathematical programming models that can be computationally solved when considering real applications. However, despite the interest on the part of these industries in counting on effective methods for production scheduling, there are few studies available on the subject. The computational tests prove the robustness and feasibility of proposed models in situations analogous to those found in production scheduling at the analyzed industrial sector.     

Seed oils of ten traditional Portuguese grape varieties with interesting chemical and antioxidant properties

To increase the potential and better exploring of grape seeds that are an important wine-industrial waste, oils of ten traditional Portuguese grape varieties were evaluated in relation to their vitamin E content (tocopherols and tocotrienols), fatty acid profile, as well as, antioxidant properties. Our results showed that the grape-seed oils were a good source of γ-tocotrienol (499–1575 mg/kg), α-tocopherol (85.5–244 mg/kg) and α-tocotrienol (69–319 mg/kg). Concerning fatty acid profile, linoleic (C18:2cc), oleic (C18:1), palmitic (C16:0) and stearic (C18:0) acids were the predominant. Grape-seed oils demonstrated to be a good source of polyunsaturated fatty acids (PUFAs) (63.64–73.53%), whereas monounsaturated fatty acid (MUFA) and saturated fatty acid (SFA) ranged between 14.19–21.29% and 11.64–14.94%, respectively. Interesting values of DPPH and ABTS radical scavenging activities were also obtained. This study demonstrated that these seeds may be reused and their oils incorporated in other food products, taking into account the compounds with positive effects on human health that are present in their composition.     

Optimisation of the extraction of phenolic compounds and antioxidant activity from aerial parts of Bidens pilosa L. using response surface methodology

Response surface methodology was used to find the optimum ethanol concentration and temperature which maximises the antioxidant activity (AA) of hydroalcoholic extracts from aerial parts of Bidens pilosa L. A rotatable central composite design was used, and the extracts were characterised by the determination of solid concentration (SC), total flavonoid (TFC) and total polyphenol content (TPC). AA was determined through 2,2′‐azinobis (3‐ethylbenzothiazoline‐6‐sulphonic acid) diammonium salt (ABTS) and 2,2‐diphenyl‐1‐pycrylhydrazyl (DPPH) radical scavenging activity. Mathematical models showed the significant effects of each variable and allowed to select the optimum conditions of ethanol concentration (62.7%) and extraction temperature (66.2 °C). The optimised extract presented an AA of 804.9 ± 12.2 Trolox equivalent antioxidant capacity (TEAC) dry base (d.b.) for DPPH and 515.8 ± 31.8 TEAC d.b. for ABTS. It was observed that both TFC and TPC showed a good correlation with AA of the extracts.     

Functionalization of wool fabric with phase‐change materials microcapsules after plasma surface modification

The use of microcapsules has increased in several different areas, namely, textile applications. They have been used as a possible means of introducing new properties, namely, in medical care by antibiotics, skin moisturizers, and other drugs and for thermal comfort. In this study, we examined the influence of dielectric barrier discharge (DBD) plasma treatment on the adhesion of phase‐change material (PCM) microcapsules on wool fabric. Several experimental techniques were used to evaluate the wool surface modification after plasma treatment and the influence of the microcapsules' resistance to washing conditions, namely, the determination of the static and dynamic contact angles, surface energy, and adhesion work; X‐ray photoelectron spectroscopy; Fourier transform infrared spectroscopy; differential scanning calorimetry; and scanning electron microscopy. Chemical and physical characterization of the wool fiber in the fabric confirmed significant surface modification. The plasma treatment greatly increased the hydrophilicity, surface energy, and adhesion work of the wool fabric; this proved that more microcapsules were adsorbed on the fabric and more microcapsules remained on the fabric surface after the washing procedures. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Magnetic effect in multilayer Fe/Cr films

Ferromagnetic resonance measurements on different Fe/Cr multilayer samples with the same thickness of the spacing Cr layers suggest that these multilayers have a different magnetic behavior depending on the thickness of the active Fe layers. In this work we show that the change of magnetic behavior from bulk mode to surface mode is observed only when the thickness of the Fe layers is less than 4 nm. This is attributed to the Fe layer thickness and to the relative thickness of the magnetic and non-magnetic layers. ©1999Kluwer Academic Publishers     

Ground grid design of a transition station system-a typical exampleof fault transfer

E.T.D. Barra Funda I urban station, located in Sao Paulo, Brazil, is surrounded by several buildings, so it is not possible to make reliable earth resistivity and ground electrode resistance measurements. The grounding of this station was designed by using external circuits connected to the ground mat (sheaths and bare copper bondings). The use of these circuits allows a transfer of the fault potentials from E.T.D. Barra Funda I to E.T.R. Barra Funda II due to a strong cable shielding. A discussion is presented of the basic procedures adopted for controlling the potential rise at the E.T.D. Barra Funda I station in order to ensure the safety of people and equipment during the occurrence of a fault to the ground. This study deals with such design aspects as: high short-circuit level, high soil resistivity and backup protection time, and reduced area for diffusion of short-circuit current