Design of helical coil condenser of small-capacity Water/Lithium Bromide absorption cooling machine

Absorption machines are considered as a good alternative to vapor compression systems in terms of energy efficiency and environmental impacts. However, they use undeveloped resources (industrial waste heat …) and renewable energy (solar energy …) as primary energy sources. These considerations focus on the intent of the market on small-capacity absorption machines for domestic applications. The major problem of absorption machines is the high investment cost, which is mainly due to the prices of different components of the machine. In fact, the current machines implement shell and tube heat exchangers, which are largely incompatible with small-capacity compact machines. In this context, we are interested in the study and the development of a falling film compact condenser which allows meeting these expectations and developing domestic absorption machines. This work aimed to size a new type of a falling film helical coil condenser used in an absorption machine operating with the couple water/Lithium Bromide (H₂O/LiBr) and delivering a thermal power of 10 kW. It also presents a literature review on the transfer phenomena which react during the falling film condensation and various types and modes of condensation. A dimensioning model of helical coil condenser, based on the equations and the empirical correlations of heat transfer, was developed. The proposed configuration of the helical coil condenser has a great potential because of its compact size and the minimal weight for the design of our H₂O/LiBr machine for domestic applications.     

So Useful,Those Quasicrystals

For years, the community working on quasicrystals in many countries in the world was expecting the ultimate recognition of its contribution to the advancement of crystal chemistry, solid-state physics, mathematics, and other fields. Nearly thirty years after the initial discovery, it was finally awarded in October 2011 to Prof. Danny Shechtman by the Nobel Committee for Physics and Chemistry. Many, most often independent, achievements contributed to this success. The purpose of this article is to chronicle the role played by the applications of quasicrystals and related compounds in the development of the field and its financing by governmental institutions as well as private companies. Those applications, potential or realized, have made the field of quasicrystals comprehensible to the general public and to decision makers all over the world, including in Stockholm, in spite of its rather complicated high-dimensional crystallographic background, and in spite of the absolute opposition that a great chemist manifested against it in its infancy.     

Electro-oxidation of hydrolysed poly-oxymethylene-dimethylether on PtRu supported catalysts

Poly-oxymethylene-dimethylether (CH₃-O-(CH₂-O)_n-CH₃ (n = 3), abbreviated as POMM₃), which has no toxicity and a very low vapour pressure, unlike methanol, was investigated as a possible liquid fuel for a direct oxidation-type fuel cell. The electrocatalytic activity towards the oxidation of methanol, formaldehyde and a fully hydrolysed form of POMM₃ in 0.1 mol dm⁻³ HClO₄ solution was examined from 30 °C to 90 °C by using a channel flow cell system at three different types of PtRu catalysts, dispersed on high surface area supports, i.e., carbon black, antimony-doped tin oxide (Sb-SnO₂), and the latter mixed with a certain fraction of acetylene black (AB) to improve the electronic conductivity. The PtRu/Sb-SnO₂ + AB catalyst exhibited the best electrocatalytic activity and thermal stability towards the fully hydrolysed POMM₃ and formaldehyde oxidations, for which the mass activity was about ten times higher than that for methanol.     

Influence of Rolling Element Bearing Modeling on the Predicted Thermal Behavior of the FZG Test Rig

A thermomechanical model of the FZG test rig is presented. The numerical model is based on the thermal network method and takes into account power losses due to tooth friction, rolling element bearings (REBs), oil churning, and shaft seals. Some measurements underline that REB rings run at different temperatures. To investigate this difference, several REB models are proposed and compared to measurements. Their influence on the global thermal behavior of the gear unit is discussed and analyzed.     

Pressure and Chemical Unfolding of an α-Helical Bundle Protein: The GH2 Domain of the Protein Adaptor GIPC1

When combined with NMR spectroscopy, high hydrostatic pressure is an alternative perturbation method used to destabilize globular proteins that has proven to be particularly well suited for exploring the unfolding energy landscape of small single-domain proteins. To date, investigations of the unfolding landscape of all-β or mixed-α/β protein scaffolds are well documented, whereas such data are lacking for all-α protein domains. Here we report the NMR study of the unfolding pathways of GIPC1-GH2, a small α-helical bundle domain made of four antiparallel α-helices. High-pressure perturbation was combined with NMR spectroscopy to unravel the unfolding landscape at three different temperatures. The results were compared to those obtained from classical chemical denaturation. Whatever the perturbation used, the loss of secondary and tertiary contacts within the protein scaffold is almost simultaneous. The unfolding transition appeared very cooperative when using high pressure at high temperature, as was the case for chemical denaturation, whereas it was found more progressive at low temperature, suggesting the existence of a complex folding pathway.     

Fukushima Daiichi fuel debris retrieval: results of aerosol characterization during laser cutting of non-radioactive corium simulants

ABSTRACT

The production and dispersion of contaminated aerosols during the laser cutting of corium can potentially provide useful insights into the dispersion of contamination during the evacuation of damaged reactors during decommissioning. Quantitative assessments of contamination dispersion are fundamental to the development of a safety case for the decommissioning of the Fukushima Daiichi plant. This collaborative work between IRSN, ONET Technologies and CEA, managed by the Mitsubishi Research Institute on behalf of the Japanese Ministry of Economy, Trade and Industry, presents the characterization of aerosols generated during laser cutting of corium simulants both in air and under water.

The objective is to obtain quantitative data for risk assessment related to the contamination released and disseminated when implementing this technique, over the next few years, in the process of decommissioning the damaged reactors. This paper presents a part of the results stemming from this project, focused on the characterization of aerosols produced during laser cutting of two representative corium simulants in air and underwater conditions. The experimental configuration also enabled investigation of the production of other material residues such as particle dross and water purity on the particulate composition of the aerosols. Ultimately, the radioisotope concentration distribution in the aerosols are transposed to radioactivity in order to assess the risk to radiation workers during decommissioning.     

New In Vitro Model of Oxidative Stress: Human Prostate Cells Injured with 2,2-diphenyl-1-picrylhydrazyl (DPPH) for the Screening of Antioxidants

The antioxidant activity of natural compounds consists in their ability to modulate gene and protein expression, thus inducing an integrated cell protective response and repair processes against oxidative stress. New screening tools and methodologies are crucial for the actual requirement of new products with antioxidant activity to boost endogenous oxidative stress responsive pathways, Reactive Oxygen Species (ROS) metabolism and immune system activity, preserving human health and wellness. In this study, we performed and tested an integrated oxidative stress analysis, using DPPH assay and PNT2 cells injured with DPPH. We firstly investigated the mechanism of action of the oxidising agent (DPPH) on PNT2 cells, studying the variation in cell viability, oxidative stress genes, inflammatory mediator and ROS levels. The results reveal that DPPH activated ROS production and release of Prostaglandin E₂ in PNT2 at low and intermediate doses, while cells switched from survival to cell death signals at high doses of the oxidising agent. This new in vitro oxidative stress model was validated by using Trolox, β-carotene and total extract of the green microalga Testraselmis suecica. Only the T. suecica extract can completely counteract DPPH-induced injury, since its chemical complexity demonstrated a multilevel protecting and neutralising effect against oxidative stress in PNT2.     

Flaxseed proteins: food uses and health benefits

Flaxseed proteins are potent multi‐functional ingredients for food formulation owing to their techno‐functionalities, food preservation capacity, and health benefits. A possible synergistic effect with mucilage on their functionalities could be valuable even though this co‐product in flaxseed may limit the protein yield during their production processes. Their techno‐functional properties could also be considered in mixture with other flax bioactive components such as lignans and fibre to enhance the value of the flaxseed meal. The present paper reviews flaxseed protein uses in food and their health benefits. New perspectives according to consumers’ demand for products with health promoting bioactive components are also suggested.     

Evaluation of a new method for measuring the internet degree distribution: Simulation results

Many contributions rely on the degree distribution of the Internet topology. However, current knowledge of this property is based on biased and erroneous measurements and is subject to much debate. Recently, in [1], a new approach, referred to as the Neighborhood Flooding method, was proposed to avoid issues raised by classical measurements. It aims at measuring the neighborhood of Internet core routers by sending traceroute probes from many monitors distributed in the Internet towards a given target router. In this paper, we investigate the accuracy of this method with simulations. Our results show that Neighborhood Flooding is free from the bias highlighted in the classical approach and is able to observe properly the exact degree of a vast majority of nodes in the core of the network. We show how the quality of the estimation depends on the number of monitors used and we carefully examine the influence of parameters of the simulations on our results. We also point out some limitations of the Neighborhood Flooding method and discuss their impact on the observed distribution.