Hydrophobically modified poly(ethylene glycol) as reactive clays inhibitor additive in water‐based drilling fluids

Adsorption measurements and inhibition tests were used to investigate the mechanisms of shale stabilization by hydrophobically modified poly(ethylene glycol) (PEG). Commercially available PEG with a large range of molar masses and PEG diesters were adsorbed on smectite‐rich clay from saline solutions and the clay/polymer complexes obtained were characterized by thermogravimetric analysis and x‐ray diffraction. The adsorption isotherms obtained for all unmodified PEG showed low affinity for the clay surface, however they all accessed the interlamellar spaces of the clay and reduced the clay water content of the complexes obtained. The PEG macromolecules had their affinity for the clay strongly enhanced by the hydrophobic modification especially with dodecanoic acid and were intercalated into the clay matrix, reducing, in a more efficient way, the water uptake by the clay. Conventional rolling tests were performed to evaluate the effect of polymers on the clay cuttings integrity. Results show that under conditions promoting the adsorption of polymers on both external and interlayer clay surfaces, displacement of the water from the clay was obtained and dispersion and disintegration of clay cuttings were inhibited. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Characterisation of roman mortars from Conímbriga with respect to their repair

The need for the formulation of mortars for repair of ancient Roman renders in the archaeological site of Conímbriga brought about the need for a study of the rendering solutions existent therein. Various samples were extracted and analysed by means of acid attack followed by determination of particle size distribution, execution and visualization of thin sections, thermal analysis and mineralogical and chemical analysis using XRD and XRF. This paper presents the results of four of the Conímbriga mortars; the results show similarities in terms of the raw materials that were used and crushed ceramic particle size.     

Implementing Bologna in Southern European countries: Comparative analysis of some research findings

From the European and national perspectives the analysis of policy implementation tends to focus on aspects related to the legal framework. At these levels, institutions offer “the vision of a triumphant march towards the objectives set for 2010” [Veiga, A., Amaral, A., 2006b, The open method of co-ordination and the implementation of Bologna process. Tert Educ Manage, 12(4): 283–295]. There are several factors influencing this perspective: policy implementation is viewed as a linear process, which is an outdated perspective and obscures a number of interlocking dimensions; the political time is not aligned with the academic time, preventing a reform in substance and the competitive emulation practices emphasising the role of performance indicators stress the economic dimension [Neave, G., 2005, On snowballs, slopes and the process of Bologna: some testy reflections on the advance of higher education in Europe, ARENA—Centre for European Studies, University of Oslo; Veiga, A., Amaral, A., 2006b, The open method of co-ordination and the implementation of Bologna process. Tert Educ Manage, 12(4): 283–295]. From the local perspective, the perceptions show that higher education institutions (HEIs) often use alternative interpretations of Bologna that suit their institutional strategies.

In this paper, the implementation is analysed using as empirical data the stocktaking exercises [Bologna Follow-up Group, 2005, Bologna process stocktaking report, in: Ministerial Meeting in Bergen, Bergen; Bologna Follow-up Group, 2007, Bologna process stocktaking report, in: Ministerial Meeting in London, London] and the material collected in two research projects (the UNIMON project [Moscati, R., 2006, University change: Italy and Europe, in: Monitoring the Reform of the Higher Education System in Six Italian Universities, Final Results, University of Milano-Biccoca, Milan] and the survey involving all Portuguese higher education institutions that presented new degree programmes or adaptations to the Bologna-type structure).

The paper starts by providing the broad context of the Bologna process putting emphasis on the instruments that have been used to steer the agenda. The analysis of policy implementation is based on both the depiction of policy contexts of Southern European countries and on the confrontation of the stocktaking results with those contexts to conclude that the initiative lies at present with the HEIs.     

Experimental applications of mortars with pozzolanic additions: Characterization and performance evaluation

Old fortresses near the coast of Lisbon have been originally rendered with very durable lime mortars, sometimes showing pozzolanic reactions (Silva A. Caracterização de argamassas antigas – casos paradigmáticos (in Portuguese). Lisbon: LNEC; October 2002. Cadernos Edif?´cios, No. 2. p. 87–101; Pinto J, Silva A. Lime mortars with pozzolans. The S. Julião da Barra and Ericeira case studies (in Portuguese). In: 3rd ENCORE, Encontro sobre Conservação e Reabilitação de Edif?´cios. Lisbon: LNEC; May 2003), but their very severe environmental conditions – salty atmosphere and sea water close to foundations and walls, mechanical action of the waves, hot sun and temperature variations, strong wind – and also some lack of knowledge concerning maintenance and conservation techniques, produced the deterioration of these renders and the need for their substitution.The best options were thought to be lime mortars with pozzolanic additions.Because of the lack of experience with modern pozzolanic mortars on sea environment, it was decided to carry out experimental applications on one of the Fortresses’ walls of renders with different pozzolanic additives and of some comparison mortars with known performance. Tests were carried out in situ and in laboratory and one of the formulations was chosen for application as a substitution render of the Fortress’s walls.     

Wettability alteration of oil-wet carbonate rocks by chitosan derivatives for application in enhanced oil recovery

The increasing demand for oil and the fast decline of crude oil production from mature fields encourages the development of new enhanced oil recovery (EOR) technologies. In this work, trimethyl chitosan (TMC) and trimethyl chitosan hydrophobized with myristoyl chloride (TMC-C14) are synthesized, and their wettability modification capacity of oil-wet carbonate rocks is evaluated through contact angle measurements, atomic force microscopy, and Raman spectroscopy. Their interaction with asphaltene molecules was evaluated through UV–Vis spectroscopy. Transport behavior and oil displacement capacity were investigated in an unconsolidated porous medium. Results show that they can modify the wettability of oil-wet carbonate rocks, turning them water-wet, promoting oil displacement increases by 25% for TMC, and 16% for TMC-C14.TMC shows a better performance for wettability alteration than TMC-C14, confirming the hypothesis that the higher the positive charge density on the polymeric surfactant structure, the more efficient will be the system as a wettability modifier and as an EOR agent.     

Nutritional composition,fatty acid profile,phytochemistry and evaluation of the effects of Carya illinoinensis on diabetes

The increase in chronic diseases has arisen interest to search for alternative treatments so that people can improve their quality of life. Thus, Carya illinoinensis is the subject of the present work which aims at determining whether it has antidiabetic activity. The plant was collected and its nuts were separated from their peels, dried and grinded and incorporated into the feed, in concentration of 6% and 10%, for the treatment of animals. The centesimal composition of this diet was also determined. From the nut was also obtained the fixed oil, for the profile of fatty acids, and the 70% hydroethanolic extract for the phytochemical analysis. The results have shown that species presents hypoglycaemic effect, high fat composition of unsaturated fatty acids and the presence of some phenolic compounds, directly related to the antidiabetic activity. Therefore, the specie presente benefits that can contribute to the binomial diet/health.     

Different cell disruption methods for obtaining carotenoids by Sporodiobolus pararoseus and Rhodothorula mucilaginosa

Food Science and Biotechnology - Since carotenoids are synthesized inside the cell, it is desirable to find an efficient method to extract carotegenic pigments. This study aimed at comparing the...     

The importance of the exact satisfaction of the incompressibility constraint in nonlinear elasticity: mixed FEMs versus NURBS-based approximations

In the present paper we investigate the capability of finite element methods to correctly reproduce the stability range of finite strain problems in the incompressible regime. To this end, we develop a numerical scheme, obtained combining a stream function formulation with an isogeometric NURBS approach, which is able to sharply estimate the stability limits of the continuous problem. Using such a method, we show a pair of benchmark problems on which various well-known finite element methods largely fail in approximating the correct stability range.