Perturbative Gravity in the Causal Approach

Quantum theory of the gravitation in the causal approach is studied up to the second order of perturbation theory. We prove gauge invariance and renormalizability in the second order of perturbation theory for the pure gravity system (massless and massive). Then we investigate the interaction of massless gravity with matter (described by scalars and spinors) and massless Yang-Mills fields. We obtain a difference with respect to the classical field theory due to the fact that in quantum field theory one cannot enforce the divergenceless property on the vector potential and this spoils the divergenceless property of the usual energy-momentum tensor. To correct this one needs a supplementary ghost term in the interaction Lagrangian.Comment: 50 pages, no figures, some changes in the last sectio

The Interaction of Quantum Gravity with Matter

The interaction of (linearized) gravitation with matter is studied in the causal approach up to the second order of perturbation theory. We consider the generic case and prove that gravitation is universal in the sense that the existence of the interaction with gravitation does not put new constraints on the Lagrangian for lower spin fields. We use the formalism of quantum off-shell fields which makes our computation more straightforward and simpler.Comment: 25 page

Photoacoustic technique for the characterization of plasmonic properties of 2D periodic arrays of gold nanoholes

We apply photo-acoustic (PA) technique to examine plasmonic properties of 2D periodic arrays of nanoholes etched in gold/chromium layer upon a glass substrate

Local Nature of Coset Models

The local algebras of the maximal Coset model C_max associated with a chiral conformal subtheory A\subset B are shown to coincide with the local relative commutants of A in B, provided A contains a stress energy tensor. Making the same assumption, the adjoint action of the unique inner-implementing representation U^A associated with A\subset B on the local observables in B is found to define net-endomorphisms of B. This property is exploited for constructing from B a conformally covariant holographic image in 1+1 dimensions which proves useful as a geometric picture for the joint inclusion A\vee C_max \subset B. Immediate applications to the analysis of current subalgebras are given and the relation to normal canonical tensor product subfactors is clarified. A natural converse of Borchers' theorem on half-sided translations is made accessible.Comment: 33 pages, no figures; typos, minor improvement

PRODUCTION STATUS OF BIOMASS PELLETS – REVIEW

The use of biomass has become extremely important for the production of clean energy from renewable sources. This is due to the continuously increased need for energy, to the possible depletion of conventional fossil fuels in the near future, and also to the regulations of European Union on the need to reduce significantly the emissions of greenhouse gases. This paper presents a synthesis on the raw materials used for pellets production, some of the important characteristics of pellets (density, ash content and heating power), and also data on the status of pellets production and consumption in different countries. Latest reported data show that the European Union is the biggest wood pellets producer globally, with a production of 13.5 million tonnes in 2014. Romania’s pellets production in 2014 was of 740000 tonnes, and estimations are that in 2020 it will exceed 1.2 million tonnes

ASPECTS REGARDING THE ENERGY POTENTIAL OF THE MISCANTHUS PLANT

Greenhouse gases resulting from human activities are the most significant driver of climate change. The use of renewable resources obtained by cultivating energy plants, that have the potential of replacing fossil fuels, is one of the most important approaches to reduce the consequences produced by this global climate change hazard.The paper presents information regarding the energy potential of the Miscanthus plant, that can be explored in three main directions: to produce bioethanol, biogas or solid biomass (chopped, pellets or briquettes), then use thermochemical processes for energy production

RESEARCH ON INDUSTRIALIZATION IN OBTAINING BIOFERTILIZERS AND BIOFUELS FROM SEAWEED

Obtaining biofertilizers and biofuels from organic products has been of great interest in recent years and is an important step in combating pests and reducing soil chemicals. Seaweed is an great agent in reduction pollution, in the textile industry, in the manufacture of pulp and paper, in distillation, in petrochemistry, metallurgy, chemistry, food, pharmaceuticals, as well as in agriculture as biofertilizers.This article presents stages of research worldwide on the potential of industrialization in obtaining biofuels and biofertilizers from seaweed.The paper highlights technologies and processing methods in obtaining future biofertilizers and biofuels with a low impact on new climate change felt strongly on agriculture

Advances in multimodality treatment of cerebral aneurysms

Background: The treatment of intracranial aneurysms has undergone a paradigm shift such that endovascular therapy has emerged as a viable treatment regimen. Thus, microsurgery techniques have become less invasive, more appealing to patients, lower risk, and efficacious for complex aneurysms, particularly those unfavorable for or failing endovascular therapy. Methods: We reviewed literature and emphasized major modern techniques used in complex aneurysm treatment. Also we present several cases of minimal invasive supraorbital „keyhole” craniotomy, used in treatment of anterior circulation aneurysms and a case report of a giant cavernous carotid aneurysm resolved with an extra-intracranial high-flow bypass and trapping of parent vessel. Results: Multimodality treatment of cerebral aneurysm provided by literature can be divided in two major groups: microsurgery and endovascular techniques. Microsurgery include: direct clip occlusion via a large or minimal invasive craniotomy, clip occlusion after coil extraction and bypass techniques; while endovascular techniques embrace: coiling, stent/balloon-assisted coiling and pipeline endovascular device flow diverter. Conclusion: Contemporary management strategies should involve all aspects of neurovascular care, including neuroendovascular physicians, neurocritical care, and neuroanesthesia. All of these specialties should be synergistic and complementary in their approach with the common goal of managing the obliteration of the aneurysm with minimal risk, both short-term and long-term, to the patient