The hydration of reactive cement-in-polymer dispersions studied by nuclear magnetic resonance

The behaviour of two novel cement-in-polymer (c/p) dispersions, namely cement-in-poly(vinyl acetate) and cement-in-poly(vinyl alcohol) upon exposure to water at room temperature was investigated by a combination of various NMR methods. The swelling, cracking, and the water ingress were monitored non-destructively using ¹H single point imaging. The hydration of the cement matrix was investigated using ²⁹Si NMR whilst ¹³C CPMAS NMR spectra allowed the quantification of the kinetics of the hydrolysis reaction of poly(vinyl acetate) into poly(vinyl alcohol). The polymer controls the rate of water ingress and swelling which in turn determines the behaviour of the c/p dispersions upon exposure to water. For the cement-in-poly(vinyl alcohol), the rates of water ingress and swelling are much faster than the hydration of the clinker whilst for the cement-in-poly(vinyl acetate) the slow rates of the two processes allow the formation of a cementious matrix which assures the stability of the sample.     

Starvation in ball bearings

A complex analytical model for the starvation mechanism in ball-race contacts, in correlation with thermal effects, has been developed. From the theoretical results it was found that in high speed, mist-lubricated ball bearings, the reduction factor of the film thickness by starvation and thermal effects can be computed in correlation with the ball-race lateral oil meniscus thicknesses. Experimental investigations of 7206 C angular contact ball bearings, operating between 5000 and 35 000 min⁻¹, are in good correlation with the theoretical results when only starvation and inlet shear heating have been included. When the ball bearing temperature increases, both the theoretical and experimental results show that starvation occurs at smaller ball-race lateral oil meniscus thicknesses, by decreasing the oil viscosity.     

Surface properties and biocompatibility of cellulose acetates

The article describes some properties of cellulose acetates (CAs) with different substitution degrees. The hydrophilic/hydrophobic properties, morphological aspects, and interface properties with red blood cells and platelets are affected by the substitution degree, synthesis conditions, history of the formed films from solutions in acetone/water nonsolvent/nonsolvent mixtures, and low pressure plasma treatment. The results obtained are useful in biomedical applications, including evaluation of bacterial adhesion onto surfaces, or utilization of CA for semipermeable membranes. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Principles for the risk assessment of genetically modified microorganisms and their food products in the European Union

Genetically modified microorganisms (GMMs) are involved in the production of a variety of food and feed. The release and consumption of these products can raise questions about health and environmental safety. Therefore, the European Union has different legislative instruments in place in order to ensure the safety of such products. A key requirement is to conduct a scientific risk assessment as a prerequisite for the product to be placed on the market. This risk assessment is performed by the European Food Safety Authority (EFSA), through its Scientific Panels. The EFSA Panel on Genetically Modified Organisms has published complete and comprehensive guidance for the risk assessment of GMMs and their products for food and/or feed use, in which the strategy and the criteria to conduct the assessment are explained, as well as the scientific data to be provided in applications for regulated products. This Guidance follows the main risk assessment principles developed by various international organisations ( and ). The assessment considers two aspects: the characterisation of the GMM and the possible effects of its modification with respect to safety, and the safety of the product itself. Due to the existing diversity of GMMs and their products, a categorisation is recommended to optimise the assessment and to determine the extent of the required data. The assessment starts with a comprehensive characterisation of the GMM, covering the recipient/parental organism, the donor(s) of the genetic material, the genetic modification, and the final GMM and its phenotype. Evaluation of the composition, potential toxicity and/or allergenicity, nutritional value and environmental impact of the product constitute further cornerstones of the process. The outcome of the assessment is reflected in a scientific opinion which indicates whether the product raises any safety issues. This opinion is taken into account by the different European regulatory authorities prior to a decision regarding authorisation to commercialise the product.     

New Potential Antitumor Pyrazole Derivatives: Synthesis and Cytotoxic Evaluation

New pyrazole derivatives were designed and synthesized as potential protein kinase inhibitors in the view to develop specific antitumor therapies. The structures of the compounds were elucidated using spectral and elemental analyses. The antitumor potential was estimated using wheat seeds and the general toxicity was evaluated by alternative methods, using invertebrate animals. One 3-aminopyrazole derivative emerged as a potential candidate for the development of future cytotoxic compounds.     

Influence of the substitution degrees on the optical properties of cellulose acetates

Cellulose acetates with different substitution degrees possess a set of properties that makes them highly suitable for optical applications. This article discusses some of these properties, namely refractivity, dielectric properties, and transmittance. The contribution of the ratio between the molar refraction, which is proportional to the induced dipole moment, and the molar volume for the different atoms present in the studied polymers to the optical properties was investigated. The study illustrates the importance of such structural and compositional characteristics in tailoring some specific optical applications. Furthermore, optical transmission has been investigated in the 200–1000 nm range. To obtain the optical parameters, the approach proposed by Tauc for amorphous semiconductors has been used because of the similarity of the absorption edges. The values of pseudogap energy ranged between 3.44 and 4.70 eV, whereas those of Urbach energy were modified in the 18–37 meV range. All parameters determined have been related to the influence of the substitution degrees and of the synthesis condition. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Implicit improved vertex control for uncertain,time-varying linear discrete-time systems with state and control constraints

The problem of regulating an uncertain and/or time-varying linear discrete-time system with state and control constraints to the origin is addressed. It is shown that feasibility and a robustly asymptotically stable closed loop can be achieved using an interpolation technique. The design method can be seen as an alternative to optimization-based control schemes such as Robust Model Predictive Control. Especially for problems requiring complex calculations to find the optimal solution, the present method can provide a straightforward suboptimal solution. A simulation demonstrates the performance of this class of constrained controllers.     

On the disturbance model in the robustification of explicit predictive control

This article deals with the predictive control for linear systems, described in a explicit form as piecewise affine (PWA) state feedback laws. The main goal is to reduce the sensitivity of these schemes with respect to the model uncertainties. This objective can be attained by considering worst-case (min–max) formulations, optimisation over the control policies or tube predictive control. Such comprehensive approaches may lead to fastidious on-line optimisation, thus reducing the range of application. In the present note, a two-stage predictive strategy is proposed, which in the first place synthesises an analytical (continuous and piecewise linear) control law based on the nominal model and secondly robustifies the control law in the neighbourhood of the equilibrium point (the feedback gain obtained for the unconstrained control problem – most often assimilated to the LQR gain). How the disturbance model corresponding to the unconstrained control robustification can be used to improve the robustness of the PWA control law is also shown.     

Photobase‐generating new polyurethanes with oxime–urethane groups in the main chain

New polymeric photobase generators containing oxime–urethane groups were prepared by the polyaddition reaction of 2,4‐tolylene diisocyanate with terephthalaldehyde dioxime in the presence or absence of a polyol component to study the ability of these polymers to generate amines through the photolysis of oxime–urethane linkage. The amines induced the crosslinking of poly(glycidyl methacrylate), as proved by the variation of the amount of the insoluble fraction of polymer films with the heating temperature and/or irradiation time. UV and IR absorption spectra indicated that the thermal crosslinking of poly(glycidyl methacrylate) was catalyzed by the photogenerated amines. The photobehavior of the polymers was followed by a reduction of the absorption band at 290 nm, which was characteristic of oxime–urethane groups, as a function of the UV irradiation time. Blue fluorescence was visualized by the treatment of irradiated films with fluorescamine. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2324–2332, 2004     

Emergency management: does it have a sufficiently comprehensive understanding of decision-making, process and context?

It is widely recognised in the social and management sciences that the effective support of decision-making requires a multidisciplinary perspective. This trend is also clear in nuclear emergency management (EM). However, communication between disciplines is not easy to maintain in EM contexts when the decision makers (DMs) are likely to be highly stressed. Such circumstances can lead them to revert to the instinctive patterns of perception of their core disciplines, making communication between disciplines difficult and, perhaps, obscuring complex interactions that have not been rehearsed in practice exercises. This paper explores decision making in EM and the nature of the socio-technical issues that will arise, suggesting that despite the lessons of past accidents the research EM community is still not taking a broad enough view of what future incidents may entail.