Synergistic Interaction of Dyes and Semiconductor Quantum Dots for Advanced Cascade Cosensitized Solar Cells

A new procedure for the cosensitization with quantum dots (QDs) and dyes for sensitized solar cells is reported here. Cascade cosensitization of TiO₂ electrodes is obtained by the sensitization with CdS QDs and zinc phthalocyanines (ZnPcs), in which ZnPcs containing a sulfur atom are specially designed to produce a cascade injection by direct attachment to QDs. This strategy causes a double synergetic interaction. This is the differentiating point of cascade cosensitization in comparison with other approaches in which dyes with conventional functionalization are anchored to TiO₂ electrodes. Cosensitization produces a panchromatic response from the visible to near‐IR region already observed with other sensitization strategies. However, cascade cosensitization produces in addition a synergistic interaction between QDs and dye, that it is not merely limited to the complementary light absorption, but dye enhances the efficiency of QD sensitization acting as a passivating agent. The cascade cosensitization concept is demonstrated with using [Co(phen)₃]^3+/2+ redox electrolyte. The TiO₂/CdS QD‐ZnPc/[Co(phen)₃]^3+/2+ sensitized solar cell shows a large improvement of short‐circuit photocurrent and open‐circuit voltage in comparison with samples just sensitized with QDs. The advent of such cosensitized QD‐ZnPc solar cells paves the way to extend the absorbance region of the promising QD‐based solar cells and the development of a new family of molecules designed for this purpose.     

Hydrothermal oxidation: application to the treatment of different cutting fluid wastes

The aim of this work is to present the application of the hydrothermal oxidation in supercritical conditions, also named supercritical water oxidation (SCWO) to the treatment of two commercial cutting fluids: Biocut and Servol. Experiments were carried out in a continuous flow system at a constant pressure of 25 MPa, using pure oxygen as oxidant in excess, and different temperatures ranging from 673 to 773 K. Both semi-synthetic cutting fluids are a mixture of several compounds so the efficiency of the oxidation process was followed in terms of the reduction in chemical oxygen demand (COD) and total organic carbon (TOC). A comparison of the results obtained in the study showed that it is possible to apply successfully SCWO for both cutting fluids, obtaining more than 95% for both COD and TOC removal at 773 K. However, the results also show that different residence times are needed to obtain the same percentage of COD or TOC removal depending on the cutting fluid treated, being in all cases Servol easier to oxidize than Biocut. A kinetic model to predict COD and TOC conversion has been proposed for both cutting fluids. A two-parameter mathematical model involving two steps (a fast reaction followed by a slow reaction) was used to describe the Biocut SCWO kinetics and to calculate the kinetic constants.     

Resource allocation strategies for full frequency reuse in tri‐sectorized multi‐cell orthogonal frequency division multiple access systems

In this paper, we propose several frequency reuse coordination schemes for interference management in orthogonal frequency division multiple access. The aim of these schemes, working together with time and frequency domain packet scheduling, is to achieve reuse of 1 at sector level in a tri‐sectorized base station scenario. Inter‐sector interference is strong at the frontier between sectors, and a tight coordination scheme needs be applied. To support this coordination scheme, the users' location information is then essential to determine if a user is prone to suffer strong inter‐sector interference. The performance of these resource allocation algorithms is compared with schemes based on fractional frequency reuse, where reuse of 1 at cell level is assumed. Copyright © 2012 John Wiley & Sons, Ltd.     

Challenges associated with spray drying of lactic acid bacteria: Understanding cell viability loss

Lactic acid bacteria (LAB) cultures used in food fermentation are often dried to reduce transportation costs and facilitate handling during use. Dried LAB ferments are generally lyophilized to ensure high cell viability. Spray drying has come to the forefront as a promising technique due to its versatility and lower associated energy costs. Adverse conditions during spray drying, such as mechanical stress, dehydration, heating, and oxygen exposure, can lead to low LAB cell viability. This reduced viability has limited spray drying's industrial applications thus far. This review aims to demonstrate the operations and thermodynamic principles that govern spray drying, then correlate them to the damage suffered by LAB cells during the spray-drying process. The particularities of spray drying that might cause LAB cell death are detailed in this review, and the conclusion may enhance future studies on ways to improve cell viability.     

Potential applications of recombinant bifidobacterial proteins in the food industry,biomedicine, process innovation and glycobiology

Food Science and Biotechnology - Bifidobacterial proteins have been widely studied to elucidate the metabolic mechanisms of diet adaptation and survival of Bifidobacteria, among others. The use of...     

Environmental tobacco smoke exposure in public places of European cities

Background: Exposure to environmental tobacco smoke (ETS) has important public health implications. The results of the first European multi-centre study that measured ETS exposure in a range of public places (transport, educational settings, and leisure facilities such as bars and restaurants) are presented.     

Using virtual reality to study the effect of information redundancy on evacuation effectiveness

The International Organization for Standardization evacuation alarm (ISO 8201: 2017) is ineffective in initiating evacuation, particularly when people are engaged in pre-evacuation activities, and it is not easy to conduct experiments for evaluating evacuation behavior due to ethical and cost issues. A virtual building emergency where alarms went off while participants were performing activities was created to study the effect of redundancy on evacuation effectiveness. Three alarms were studied: (i) a regular nonverbal ISO alarm, (ii) a speech-inserted ISO alarm, and (iii) a technology-based ISO alarm concept (sound, visual, and haptic information). Evacuation behavior, perceived urgency, and delay time were measured. Results confirmed the effect of redundancy on measurements, and participants complied better with the speech-inserted and technology-based alarms, but there were no differences in evacuation effectiveness between them. Participants perceived higher urgency from the technology-based solution, which can be more adaptive in complicated environments where background noise and language/education barriers are problems. Otherwise, the speech-inserted alarm is more cost-effective.