Real‐time monitoring by proton relaxometry of radical polymerization reactions of acrylamide in aqueous solution

The potential of time‐domain nuclear magnetic resonance (TD‐NMR) for the real‐time monitoring of solution radical polymerizations is demonstrated. A model system composed of a redox‐pair initiator system, acrylamide as monomer and water as solvent was investigated. A second‐generation continuous wave free precession technique was employed to measure the longitudinal relaxation time constant (T₁) of the samples throughout the polymerization reactions. This parameter was shown to be sensitive to the reactant feed free‐radical enhancement of the water molecule relaxation time, making it a good probe to monitor monomer conversion in real time in an automated, non‐destructive fashion. It was found that the T₁ value was better than the transverse relaxation time constant (T₂) for describing the evolution of the polymerization reactions, due to its greater sensitivity to paramagnetic effects. The TD‐NMR signal variation observed was linked to the formation, propagation and termination steps of the radical polymerization kinetics scheme. These first results may contribute to the application of real‐time monitoring of radical polymerization reactions employing low‐cost and robust TD‐NMR spectrometers. © 2018 Society of Chemical Industry     

A simple model for the semicontinuous heterophase polymerization: Ethyl methacrylate as a case example

A simple but comprehensive model considering homogeneous and micellar nucleation, coagulation, entry of radicals to particles and to micelles and radicals' exit from particles, is presented. The model is validated, in a starved semicontinuous heterophase polymerization of ethyl methacrylate, at three monomer addition rates. The model accurately describes the overall and instantaneous conversion, the average particle density and diameter, and the number and weight average molar masses evolutions over time. It is found that even though the average number of radicals is much smaller than 0.5, the system is not 0-1. An empirical function was used to describe the gel effect. The homogeneous nucleation was the prevailing mechanism for particle formation and large exit rates of radicals were observed. POLYM. ENG. SCI., 60: 223–232, 2019. © 2019 Society of Plastics Engineers     

Multi-level attention model for tracking and segmentation of objects under complex occlusion

A multi-level attention framework for tracking and segmentation of humans and objects under complex occlusions is investigated, featuring an effective probabilistic appearance-based technique for pixel reclassification during object grouping and splitting. A novel ’spatial-depth affinity metric’ is introduced in the conventional likelihood function, utilising information of both spatial locations of pixels and dynamic depth ordering of the component objects in grouping. Depth ordering estimation is achieved through a combination of top-down and bottom-up approach. Experiments on some realworld difficult scenarios of low quality and highly compressed videos demonstrate the very promising results achieved.     

Evaluating the application of a decision support system in identifying adequate wastewater treatment for small communities. A case study: the Fluvia River Basin.

The identification of adequate wastewater treatment for small communities is a complex problem since it demands a combination of data from different sources, such as aspects of the community and landscape, the receiving environment and the available wastewater treatment technologies. The Catalan Water Agency (Agència Catalana de l'Aigua) considered using an EDSS (Environmental Decision Support System) as a tool to help water managers select the most adequate treatment for the urban wastewater of nearly 3,500 small communities in Catalonia (Spain). From that moment, EDSS was applied to all the river basins in Catalonia. In this paper the authors present the results obtained for the 76 small communities located in one of these river basins: the Fluvia River Basin. The characteristics of the community used in the reasoning process of the EDSS, the list of selected wastewater treatment alternatives, the technical environmental justification for the selected treatments and the reasons for discarding, favouring or disadvantaging them are presented. Finally, some results for the Fluvia River Basin are compared with those obtained in other Catalan river basins with different characteristics in order to evaluate which are the significant features in identifying adequate wastewater treatments.     

Grouped Approach for the Design of H.264/AVC Motion Estimation Architectures

This letter presents a novel approach for organizing computational resources into groups within H.264/AVC motion estimation architectures, leading to reductions of up to 75% in the equivalent gate count with respect to state‐of‐the‐art designs.     

Cost-effective smart power CMOS/DMOS technology: design methodology for latch-up immunity

To answer to the need of a cost effective smart power technology, an original design methodology that permits implementing latch-up free smart power circuits on a very simple CMOS/DMOS technology is proposed. The basic concept used to this purpose is letting float the wells of the MOS transistors most susceptible to initiate latch-up. The efficiency of the design methodology is experimentally shown.     

Organizational determinants of IT adoption in the pharmaceutical distribution sector

The aim of this paper is to propose new organizational factors that might explain the differences in the extent and the speed of IT adoption. With this in mind, we carried out an analysis of 16 cases in the pharmaceutical distribution sector in Spain. The results indicate that there are certain intangible assets that favour the introduction and development of IT. Among these are a frank and fluid communication between departments and members of the organization, low levels of conflict, the explicit support of top management towards IT adoption and learning and creative skills of IT-staff. In addition to these factors, we found others that we propose as catalysts of IT adoption. Among these we might mention the special relationship between the member-clients and the company in the case of cooperative firms.     

Modelling the kinetics of antigen-antibody reactions at particle enhanced optical immunoassays

Functionalized latexes coated by antibodies are used in diagnostic tests for the detection of antigens in biological fluids. A simple kinetic model is presented which is related to the optical monitoring of the formation of specific complexes between antigen and antibody amplified by latex beads. The antibodies are chemically coupled onto chloromethylstyrene (CMST) particles. The kinetic model is able to describe the immunoprecipitin curves of immunolatex beads. The number of fitting parameters is relatively reduced (only three), and the meaning of these parameters can be interpreted in terms of the chemical equilibrium constant, the percentage of active IgG on the latex beads, and optical response. The model explains very well the optical response of immunolatex prepared by covalent coupling of antibodies on polymer carriers.