Quantum gravitational contributions to quantum electrodynamics

Quantum electrodynamics describes the interactions of electrons and photons. Electric charge (the gauge coupling constant) is energy dependent, and there is a previous claim that charge is affected by gravity (described by general relativity) with the implication that the charge is reduced at high energies. But that claim has been very controversial with the situation inconclusive. Here I report an analysis (free from earlier controversies) demonstrating that that quantum gravity corrections to quantum electrodynamics have a quadratic energy dependence that result in the reduction of the electric charge at high energies, a result known as asymptotic freedom.Comment: To be published in Nature. 19 pages LaTeX, no figure

QED coupled to QEG

We discuss the non-perturbative renormalization group flow of Quantum Electrodynamics (QED) coupled to Quantum Einstein Gravity (QEG) and explore the possibilities for defining its continuum limit at a fixed point that would lead to a non-trivial, i.e. interacting field theory. We find two fixed points suitable for the Asymptotic Safety construction. In the first case, the fine-structure constant vanishes at the fixed point and its infrared ("renormalized") value is a free parameter not determined by the theory itself. In the second case, the fixed point value of the fine-structure constant is non-zero, and its infrared value is a computable prediction of the theory.Comment: 25 pages, 3 figure

Computing the effective action with the functional renormalization group

The \u201cexact\u201d or \u201cfunctional\u201d renormalization group equation describes the renormalization group flow of the effective average action \u393 k. The ordinary effective action \u393 0 can be obtained by integrating the flow equation from an ultraviolet scale k= \u39b down to k= 0. We give several examples of such calculations at one-loop, both in renormalizable and in effective field theories. We reproduce the four-point scattering amplitude in the case of a real scalar field theory with quartic potential and in the case of the pion chiral Lagrangian. In the case of gauge theories, we reproduce the vacuum polarization of QED and of Yang\u2013Mills theory. We also compute the two-point functions for scalars and gravitons in the effective field theory of scalar fields minimally coupled to gravity. \ua9 2016, The Author(s)

CFD model of the CNG direct injection engine

The paper presents CFD analysis of fuel flow in the CNG injector. The issues such a pressure drop along an injector channel, mass flow through the key sections of the injector geometry, flow rates, the impact of the needle shape on the deflection of the sprayed gas cone and the impact of the wall head are analyzed in the article. The simulation was made in the transient states conditions for full injection process, including the opening and closing of the injector. An injection time of 6 ms, velocity of 0.33 mm/ms and a lift of 0.5 mm were selected for opening and closing of injector based on experimental test. The simulation shows that the volume inside the injector is a kind of fuel accumulator, and the opening process of the needle influence the flow parameters in an inlet cross-section after a certain time, depending on a channel cross section. The calculations allowed to select the ratio of an injector duct cross sectional area to the aperture area of the injection capable of the reducing pressure loss. The unusual location of the injector in the socket of a glow plug in the Andoria ADCR engine makes a stream be impaired by a part of the head. This research result would be useful in developing an injector construction which will be used for an investigation of CNG addition into diesel engine

Designing of Wankel engine injection adapter using rapid prototyping method

W artykule przedstawiono proces wytwarzania adaptera wtryskiwaczy silnika Wankla. Zaprezentowano etap projektowania adaptera w systemie CAD (Catia v5) przy użyciu zawansowanych technik komputerowego wspomagania projektowania. Przedstawiono proces wytwarzania adaptera techniką Rapid Prototyping przy użyciu drukarki 3D - ZPrinter 450 oraz zaprezentowano gotowy element wytworzony za pomocą obróbki CNC.The article presents the 3D printing process of a Wankel engine injector adapter. The paper presents the design stage of an adapter in a CAD (Catia V5) by using advanced computer-aided design techniques. Article shows the process of printing an adapter using rapid prototyping technique in 3D Printer - ZPrinter 450. In the end the finished item produced by the CNC is presented

Model termodynamiczny gwiazdowego silnika lotniczego ASz-62IR

The article presents assumptions of the one-dimensional model of the ASz-62IR aircraft engine. This model was developed in the AVL BOOST software. The ASz-62IR is a nine cylinder, aircraft engine in a radial configuration. It is produced by the Polish company WSK “PZL-Kalisz” S. A. The model is used for calculating parameters of the fuel stream and the air stream in intake system of the engine, as well as for the analyses of the combustion process and the exhaust flow to the external environment. The model is based on the equations describing the isentropic flow. The geometry of the channels and all parts of the model has been mapped on the basis of empirical measurements of the engine elements. The model assumes indirect injection where the gasoline was used as a fuel with the calorific value of 43.5 MJ/kg. The model assumes a mixture of a stoichiometric ratio of 14.5. This model is only part of the overall the ASz-62IR engine model. After the simulation tests on the full model the obtained results confirmed the correctness of the model used to create the mixture. It was found that the AVL BOOST software is good for the implementation of this type of work.W artykule przedstawiono założenia jednowymiarowego modelu wymiany ładunku z silnika lotniczego ASz-62IR. Model ten został opracowany w programie AVL BOOST. Silnik ASz-62IR jest dziewięciocylindrowym silnikiem lotniczym w układzie gwiazdy. Jest on produkowany przez polską firmę WSK „PZL-Kalisz” S.A. Opracowany model służy do obliczania parametrów strumienia paliwa i powietrza w układzie dolotowym silnika, jak również do analizy procesu spalania i przepływu spalin do środowiska zewnętrznego. Model jest oparty na równaniach opisujących przepływ izentropowy. Geometrię kanałów i wszystkich przepływowych elementów modelu odwzorowano na podstawie empirycznych pomiarów konstrukcji silnika. W modelu założono wtrysk pośredni, a jako paliwo zastosowano benzynę o wartości opałowej 43,5 MJ/kg. Założono stechiometryczną mieszankę o współczynniku 14,5. Opisany model jest tylko częścią całkowitego modelu silnika ASz-62IR. Po wykonaniu badań symulacyjnych pełnego modelu uzyskano wyniki potwierdzające prawidłowość zastosowanego modelu tworzenia mieszanki oraz stwierdzono przydatność oprogramowania AVL BOOST do realizacji tego typu prac

3D modeling of the SI engine intake process

W Politechnice Lubelskiej powadzone są prace mające na celu opracowanie systemu zasilania wodorem silnika o ZI. W celu poznania zjawisk zachodzących podczas procesu napełniania silnika przeprowadzono badania modelowe z wykorzystaniem oprogramowania AVL Fire. W artykule przedstawiono wyniki badań modelowych ilustrujące zjawiska związane z przepływem powietrza przez kanały dolotowe silnika jak również ruch powietrza w komorze spalania.Hydrogen supply system for SI engines is developed in Lublin University of Technology. To learn the phenomena that occur during the engine filling process, AVL based modeling was performed. This paper describes the results of the modeling studies to show the air flow through engine intake duct and the air movement in the combustion chamber

Hydrogen-powered automotive engine model

W artykule przestawiono model silnika opracowany w programie AVL BOOST. Model oparto na rzeczywistym czterocylindrowym silniku o oznaczeniu A14XER, który spełnia normę emisji spalin EURO 5. Wykonano obliczenia dla pełnego obciążenia silnika. Wyznaczono charakterystykę zewnętrzną silnika oraz porównano ją z badaniami eksperymentalnymi. Przedstawiono również wyniki obliczeń uzyskane podczas zasilania silnika mieszaniną benzyny oraz wodoru. Analizie poddano osiągi silnika.A hydrogen-powered engine model developed in AVL BOOST is studied in this paper. The model is based on the A14XER real four-cylinder engine which complies with the EURO 5 standards. The calculations are done for full load. The engine external characteristics is specified and compared with experimental studies. The paper reports the results from the calculation of a gasoline and hydrogen mixture supply and the engine performance examination