Dynamics of fermions coupling to a U(1) gauge field in the limit e2→∞e^2\to\infty

We study in this paper the properties of a gas of fermions coupling to a U(1) gauge field at wavevectors $q<\Lambda<<k_F$ at dimensions larger than one, where $\Lambda<<k_F$ is a high momentum cutoff and $k_F$ is the fermi wave vector. In particular, we shall consider the $e^2\to\infty$ limit where charge and current fluctuations at wave vectors $q<\Lambda$ are forbidden. Within a bosonization approximation, effective actions describing the low energy physics of the system are constructed, where we show that the system can be described as a fermion liquid formed by chargeless quasi-particles which has vanishing wavefunction overlap with the bare fermions in the system.Comment: 25 page

Astrometry and geodesy with radio interferometry: experiments, models, results

Summarizes current status of radio interferometry at radio frequencies between Earth-based receivers, for astrometric and geodetic applications. Emphasizes theoretical models of VLBI observables that are required to extract results at the present accuracy levels of 1 cm and 1 nanoradian. Highlights the achievements of VLBI during the past two decades in reference frames, Earth orientation, atmospheric effects on microwave propagation, and relativity.Comment: 83 pages, 19 Postscript figures. To be published in Rev. Mod. Phys., Vol. 70, Oct. 199

Comparative life cycle assessment of LED lighting products

LED lighting products used in lighting applications and their subsequent environmental impact are growing rapidly. However, there are no in-depth updated studies that show how to assess and compare them for eco-design purposes. This research aims to add insights in this area to inform eco-design by assessing and comparing the environmental impact of a new LED eco-lighting product with an existing LED lighting product. A cradle to grave Life Cycle assessment (LCA) was conducted using ReCiPe Midpoint and Endpoint (H) life cycle impact assessment method with Simapro software. The system boundaries included all product life cycle stages, except the maintenance of the luminaires and the manufacturing of the packaging. A novel functional unit was defined for the assessment, which is more suitable for the LED lighting products. Six scenarios were considered, including three probable useful lives of the luminaires (1,000, 15,000 and 40,000 h) and two end of life options (domestic bin and recycling centre). The LCA results revealed that the new eco-lighting product has about 60% less environmental impact than the existing lighting product in all scenarios. The life cycle stages with the highest environmental impact are: 1) Use, 2) Manufacturing, 3) End of Life and 4) Transport. Based on the results obtained, recommendations for eco-design of LED lighting products were proposed, and challenges of application of LCA for the eco-design were discussed

Defining freshwater as a natural resource: a framework linking water use to the area of protection natural resources

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: While many examples have shown unsustainable use of freshwater resources, existing LCIA methods for water use do not comprehensively address impacts to natural resources for future generations. This framework aims to (1) define freshwater resource as an item to protect within the Area of Protection (AoP) natural resources, (2) identify relevant impact pathways affecting freshwater resources, and (3) outline methodological choices for impact characterization model development. Methods: Considering the current scope of the AoP natural resources, the complex nature of freshwater resources and its important dimensions to safeguard safe future supply, a definition of freshwater resource is proposed, including water quality aspects. In order to clearly define what is to be protected, the freshwater resource is put in perspective through the lens of the three main safeguard subjects defined by Dewulf et al. (2015). In addition, an extensive literature review identifies a wide range of possible impact pathways to freshwater resources, establishing the link between different inventory elementary flows (water consumption, emissions, and land use) and their potential to cause long-term freshwater depletion or degradation. Results and discussion: Freshwater as a resource has a particular status in LCA resource assessment. First, it exists in the form of three types of resources: flow, fund, or stock. Then, in addition to being a resource for human economic activities (e.g., hydropower), it is above all a non-substitutable support for life that can be affected by both consumption (source function) and pollution (sink function). Therefore, both types of elementary flows (water consumption and emissions) should be linked to a damage indicator for freshwater as a resource. Land use is also identified as a potential stressor to freshwater resources by altering runoff, infiltration, and erosion processes as well as evapotranspiration. It is suggested to use the concept of recovery period to operationalize this framework: when the recovery period lasts longer than a given period of time, impacts are considered to be irreversible and fall into the concern of freshwater resources protection (i.e., affecting future generations), while short-term impacts effect the AoP ecosystem quality and human health directly. It is shown that it is relevant to include this concept in the impact assessment stage in order to discriminate the long-term from the short-term impacts, as some dynamic fate models already do. Conclusions: This framework provides a solid basis for the consistent development of future LCIA methods for freshwater resources, thereby capturing the potential long-term impacts that could warn decision makers about potential safe water supply issues in the future

Serum-Free Cryopreservation of Five Mammalian Cell Lines in Either a Pelleted or Suspended State

Herein we have explored two practical aspects of cryopreserving cultured mammalian cells during routine laboratory maintenance. First, we have examined the possibility of using a serum-free, hence more affordable, cryopreservative. Using five mammalian lines (Crandell Feline Kidney, MCF7, A72, WI 38 and NB324K), we found that the serum-free alternative preserves nearly as efficiently as the serum-containing preservatives. Second, we compared cryostorage of those cells in suspended versus a pellet form using both aforementioned cryopreservatives. Under our conditions, cells were in general recovered equally well in a suspended versus a pellet form

Організаційно-економічне забезпечення розвитку електронної промисловості

Розкрито питання організаційно-економічного забезпечення електронної промисловості в рамках організаційно-економічного механізму розвитку електронної промисловості на інноваційній основі, який регламентує діяльність державних, галузевих і підприємницьких структур, що забезпечують розвиток електронної промисловості. Ключові слова: електронна промисловість, організаційне забезпечення розвитку електронної промисловості, організаційно-економічний механізм, інноваційний розвиток.  Раскрываются вопросы организационно-экономического обеспечения электронной промышленности в рамках организационно-экономического механизма развития электронной промышленности на инновационной основе, который регламентирует деятельность государственных, отраслевых и предпринимательских структур, обеспечивающих развитие электронной промышленности. Ключевые слова: электронная промышленность, организационное обеспечение развития электронной промышленности, организационно-экономический механизм, инновационное развитие.  The paper deals with the issues of organizational and economic support of electronic industry in the framework of the organizational and economic mechanism of the above industry development on the basis of innovation. It regulates the activities of the government, sectoral and business organizations, which provide the development of the electronic industry. The proposalsare as follows: to work out a State Program of Development of the Electronic Industry, andto create a sectoral information system, a cluster “development of the electronic industry”, holding the electronic industry, a sectoral technology transfer system, training educational and scientific centres for the engineering staff. It is shown that at a corporate level the development of electronic industry is promoted by establishment of production facilities with the use of well-known brands and foreign electronic productions, technologies transfer with consideration of supply channels, introduction of business market mechanisms, IPC standards, and production information systems PDM/PLM. A specific feature of these measures is that to develop the issues of financial and economic, technical and technological, innovation and market support of the electronic industry development the methods of grouping, generalization of economic indicators received from the enterprises of this industry, and economic mathematical modelling using a correlation regression and structural logical analysis have been used. The application of these methods suggests that the use of the organizational and economic support contributes to promising development of the electronic industry in Ukraine which consists in formation of the core of the electronic industry and its integration in the world electronic space in the future. Keywords: electronic industry, organizational support of electronic industry development, organizational and economic mechanism, innovation-based development

Sub-surface Oxygen and Surface Oxide Formation at Ag(111): A Density-functional Theory Investigation

To help provide insight into the remarkable catalytic behavior of the oxygen/silver system for heterogeneous oxidation reactions, purely sub-surface oxygen, and structures involving both on-surface and sub-surface oxygen, as well as oxide-like structures at the Ag(111) surface have been studied for a wide range of coverages and adsorption sites using density-functional theory. Adsorption on the surface in fcc sites is energetically favorable for low coverages, while for higher coverage a thin surface-oxide structure is energetically favorable. This structure has been proposed to correspond to the experimentally observed (4x4) phase. With increasing O concentrations, thicker oxide-like structures resembling compressed Ag2O(111) surfaces are energetically favored. Due to the relatively low thermal stability of these structures, and the very low sticking probability of O2 at Ag(111), their formation and observation may require the use of atomic oxygen (or ozone, O3) and low temperatures. We also investigate diffusion of O into the sub-surface region at low coverage (0.11 ML), and the effect of surface Ag vacancies in the adsorption of atomic oxygen and ozone-like species. The present studies, together with our earlier investigations of on-surface and surface-substitutional adsorption, provide a comprehensive picture of the behavior and chemical nature of the interaction of oxygen and Ag(111), as well as of the initial stages of oxide formation.Comment: 17 pages including 14 figures, Related publications can be found at http://www.fhi-berlin.mpg.de/th/paper.htm

Does Pelletizing Catalysts Influence the Efficiency Number of Activity Measurements? Spectrochemical Engineering Considerations for an Accurate Operando Study

International audienc

Spectroscopic and computational insights on catalytic synergy in bimetallic aluminophosphate catalysts

A combined electronic structure computational and X-ray absorption spectroscopy study was used to investigate the nature of the active sites responsible for catalytic synergy in Co-Ti bimetallic nanoporous frameworks. Probing the nature of the molecular species at the atomic level has led to the identification of a unique Co-O-Ti bond, which serves as the loci for the superior performance of the bimetallic catalyst, when compared with its analogous monometallic counterpart. The structural and spectroscopic features associated with this active site have been characterized and contrasted, with a view to affording structure property relationships, in the wider context of designing sustainable catalytic oxidations with porous solids