scholarly journals A General Framework for Crankshaft Balancing and Counterweight Design

2021 ◽  
Vol 11 (19) ◽  
pp. 8997
Author(s):  
Alberto Dagna ◽  
Cristiana Delprete ◽  
Chiara Gastaldi
Keyword(s):  
General Framework ◽  
Combustion Engine ◽  
Matrix Formulation ◽  
Dynamic Balancing ◽  
Present Contribution ◽  
Fundamental Parameters ◽  
Centre Of Gravity ◽  
The Masses ◽  
Optimisation Procedure ◽  
Engine Size

In the automotive field, the requirements in terms of carbon emissions and improved efficiency are shifting the focus of designers towards reduced engine size. As a result, the dynamic balancing of an engine with strict limitations on the number of cylinders, the weight and the available space becomes a challenging task. The present contribution aims at providing the designer with a tool capable of selecting fundamental parameters needed to correctly balance an internal combustion engine, including the masses and geometry of the elements to be added directly onto the crankshaft and onto the balancing shafts. The relevant elements that distinguish the tool from others already proposed are two. The first is the comprehensive matrix formulation which makes the tool fit for a wide variety of engine configurations. The second is an optimisation procedure that selects not only the position of the mass and centre of gravity of the counterweight but also its complete geometric configuration, thus instantaneously identifying the overall dimensions and weight of the crankshaft.

scholarly journals Fermion mass hierarchies from supersymmetric gauged flavour symmetry in 5D

2021 ◽  
Vol 10 (6) ◽  
Author(s):  
Ketan Patel
Keyword(s):  
Vacuum Expectation ◽  
Vacuum Expectation Value ◽  
Fermion Mass ◽  
Order Unity ◽  
Anomaly Cancellation ◽  
Fundamental Parameters ◽  
Yukawa Couplings ◽  
Fifth Dimension ◽  
Fermion Masses ◽  
The Masses

A mechanism to generate realistic fermion mass hierarchies based on supersymmetric gauged U(1)_FU(1)F symmetry in flat five-dimensional (5D) spacetime is proposed. The fifth dimension is compactified on S^1/Z_2S1/Z2 orbifold. The standard model fermions charged under the extra abelian symmetry along with their superpartners live in the 5D bulk. Bulk masses of fermions are generated by the vacuum expectation value of N=2N=2 superpartner of U(1)_FU(1)F gauge field, and they are proportional to U(1)_FU(1)F charges of respective fermions. This decides localization of fermions in the extra dimension, which in turn gives rise to exponentially suppressed Yukawa couplings in the effective 4D theory. Anomaly cancellation puts stringent constraints on the allowed U(1)_FU(1)F charges which leads to correlations between the masses of quarks and leptons. We perform an extensive numerical scan and obtain several solutions for anomaly-free U(1)_FU(1)F, which describe the observed pattern of fermion masses and mixing with all the fundamental parameters of order unity. It is found that the possible existence of SM singlet neutrinos substantially improves the spectrum of solutions by offering more freedom in choosing U(1)_FU(1)F charges. The model predicts Z^\primeZ′ boson mediating flavour violating interactions in both the quark and lepton sectors with the couplings which can be explicitly determined from the Yukawa couplings.

scholarly journals A theory of colour vision

1916 ◽  
Vol 92 (642) ◽  
pp. 424-432 ◽  
Keyword(s):  
Infinite Number ◽  
Colour Vision ◽  
The Third ◽  
Centre Of Gravity ◽  
Usual Procedure ◽  
Divergence Of Opinion ◽  
Colour Blindness ◽  
The Masses ◽  
Two Sides

At the present time there is no generally accepted theory of colour vision, and there is considerable divergence of opinion as to the tests which should be applied for colour blindness. The young-Helmholtz theory certainly explains the facts of colour mixing, but it is doubtful whether we can deduce from these facts the existence of three primary colour sensations. For, if we represent colours by particles on a plane, making the masses of the particles proportional to the luminosities of the colours, and represent mixtures of these colours by the rule for determining the centre of gravity of the particles, as is done on Newton's colour diagram, then, if any triangle be drawn enclosing all the possible points, its corners may be taken as representing the three primary colours, and these corners may take up an infinite number of positions. The usual procedure is to make two sides of this triangle fit the curve representing the spectrum as closely as possible, and take two corners of the triangle on the ends of the curve. Two of the primary Colours are then definite colours of the spectrum, while the third is a sensation which can never be produced pure. But there is a certain amount of arbitrariness about this proceeding.

scholarly journals Breakdown in CO2 and CO2/C2F4 Mixtures at Elevated Temperatures in the Range 1000-4000 K

2019 ◽  
Vol 6 (1) ◽  
pp. 39-42 ◽  
Author(s):  
M. Seeger ◽  
T. Votteler ◽  
S. Pancheshnyi ◽  
J. Carstensen ◽  
A. Garyfallos ◽  
...  
Keyword(s):  
Electric Fields ◽  
Experimental Validation ◽  
Elevated Temperatures ◽  
Electric Breakdown ◽  
Circuit Breakers ◽  
Critical Fields ◽  
Present Contribution ◽  
Fundamental Parameters ◽  
Theoretical Predictions ◽  
Temperature And Pressure

CO<sub>2</sub> is a promising gas for replacement of SF<sub>6</sub> in high voltage circuit breakers. The electric breakdown in CO<sub>2</sub> and mixtures with C<sub>2</sub>F4 from PTFE nozzles is, however, still not fully understood. To understand the electric breakdown in CO<sub>2</sub> and mixtures with C<sub>2</sub>F<sub>4</sub> from PTFE nozzles fundamental parameters like the temperature and pressure dependence of critical electric fields are needed. Data on critical fields is usually available based on simulations only and experimental validation is lacking so far. Our present contribution aims to close this gap and presents experiments where the breakdown fields in uniform and weakly non-uniform electric fields are determined at various temperatures and pressures. The gas temperatures were estimated from measurements with pyrometers. The results are compared to theoretical predictions.

scholarly journals THE NEUTRALINO MASS: CORRELATION WITH THE CHARGINOS

2006 ◽  
Vol 21 (20) ◽  
pp. 1609-1623
Author(s):  
MÜGE BOZ ◽  
NAMIK K. PAK
Keyword(s):  
Standard Model ◽  
Fundamental Parameters ◽  
The Standard Model ◽  
Neutralino Mass ◽  
The Masses ◽  
Two Sectors

As the fundamental SU(2) supersymmetric parameters can be determined in the chargino sector, and the remaining fundamental parameters of the minimal supersymmetric extensions of the standard model can be analyzed in the neutralino sector, the two sectors can be correlated via these parameters. We have shown that for the CP-conserving case, the masses of all the neutralinos can be determined in terms of the chargino masses and tan β. In this case the neutralino masses are quite insensitive to the variations of tan β, they change by about 15% when tan β varies in the range from 5 to 50. In the CP-violating case, the neutralino masses are found to be quite sensitive to the variations of the CP-violating phase. For the heavier neutralinos the dependence of the masses to the CP-violating phase show complementary behavior at CP-violating points.

Active Control for the Complete Dynamic Balancing of Linkages

1992 ◽  
Author(s):  
Jorge Angeles ◽  
Meyer A. Nahon ◽  
Thomas Thümmel
Keyword(s):  
Active Control ◽  
Degree Of Freedom ◽  
Dynamic Balancing ◽  
Reaction Forces ◽  
The Masses ◽  
Inertia Forces ◽  
Shaking Moment

Abstract This paper deals with the dynamic balancing of linkages. For one-degree-of-freedom linkages, this task consists of eliminating both the shaking moment and the shaking force exerted by the inertia forces of the moving links on the frame. While the latter can be eliminated by properly deciding on both the location of the mass centers and the ratios of the masses and link lengths involved, the shaking moment due to these forces cannot be eliminated in this way. Indeed, the elimination of the shaking force is attained by having the two transmitted forces cancel each other, although each individual force does not necessarily vanish, thereby still producing a shaking moment. In this paper, we propose the use of redundant motors in order to eliminate the reaction forces transmitted to the base, thereby also eliminating the shaking moment due to these forces. However, the net moment acting on the frame is shown to be unaltered by this technique.

The Fifteenth Maudsley Lecture: The Professional Mind

1934 ◽  
Vol 80 (330) ◽  
pp. 469-481 ◽  
Author(s):  
Lord Macmillan
Keyword(s):  
Scientific Knowledge ◽  
Combustion Engine ◽  
Popular Science ◽  
Public Affairs ◽  
Market Place ◽  
Practical Applications ◽  
The People ◽  
Political Implications ◽  
Excellent Work ◽  
The Masses

In devoting to the foundation of a memorial lectureship a portion of Dr. Maudsley's bequest, the learned Society which I have this afternoon the honour to address made an indulgent concession to the laity in prescribing that the lecture to be delivered should in alternate years be of a scientific and of a popular character. This year it is the turn of the popular lecturer—a rôle which I have assumed with some trepidation. The distinction drawn is an ominous one. It seems to suggest that to be scientific you must be unpopular, and to be popular you must be unscientific. But is there necessarily so absolute a dividing line between the two domains? I hazard the view that it is possible to be at once both popular and scientific. No doubt there is still a tendency in learned circles to deride what is known as popular science, but that is an inheritance from the days of the cheap and inaccurate manuals which used to be written by imperfectly informed persons, pretentiously professing to enlighten the masses on the truths of science. Nowadays, science has become more condescending, indeed almost affable, to democracy. The approach has come from both sides, for democracy is now better educated, and science is now more expert in the art of exposition. The advent of the internal combustion engine, of wireless telegraphy and of many other practical applications of science to daily life has created a new and widespread interest and aptitude on the part of the general public in the acquisition of accurate scientific knowledge, particularly among the younger generation. At the same time the physicist, the chemist and the biologist have found it possible and worth while to impart much of their learning to wider audiences. Science is daily entering more and more into the lives of the people, with the consequence that its social, economic and political implications are being more and more realized by its professors. The President of the Royal Society has reminded us that we live in an age when the advance and development of scientific knowledge are continually creating new social and economic problems of the utmost importance, and has emphasized the necessity of bridging the gap between the scientist and the layman by every possible means. The British Science Guild, now doing such excellent work, was founded some thirty years ago by Sir Norman Lockyer for the express purpose of promoting the application of scientific method and results to social problems and public affairs. The market-place can doubtless never supersede the laboratory, but the scientist no longer disdains to take his wares to market.

scholarly journals Fundamental parameters of 4 massive eclipsing binaries in Westerlund 1

2010 ◽  
Vol 6 (S272) ◽  
pp. 515-516
Author(s):  
Eugenia Koumpia ◽  
Alceste Z. Bonanos
Keyword(s):  
Binary Systems ◽  
Local Group ◽  
Massive Stars ◽  
Eclipsing Binaries ◽  
Fundamental Parameters ◽  
Red Supergiants ◽  
The Masses ◽  
Rare Opportunity ◽  
Luminous Blue Variable

AbstractWesterlund 1 is one of the most massive young clusters known in the Local Group, with an age of 3-5 Myr. It contains an assortment of rare evolved massive stars, such as blue, yellow and red supergiants, Wolf-Rayet stars, a luminous blue variable, and a magnetar, as well as 4 massive eclipsing binary systems (Wddeb, Wd13, Wd36, WR77o, see Bonanos 2007). The eclipsing binaries present a rare opportunity to constrain evolutionary models of massive stars, the distance to the cluster and furthermore, to determine a dynamical lower limit for the mass of a magnetar progenitor. Wddeb, being a detached system, is of great interest as it allows determination of the masses of 2 of the most massive unevolved stars in the cluster. We have analyzed spectra of all 4 eclipsing binaries, taken in 2007-2008 with the 6.5 meter Magellan telescope at Las Campanas Observatory, Chile, and present fundamental parameters (masses, radii) for their component stars.

scholarly journals Asteroseismic and orbital analysis of the triple star system HD 188753 observed by Kepler

2018 ◽  
Vol 617 ◽  
pp. A2 ◽  
Author(s):  
F. Marcadon ◽  
T. Appourchaux ◽  
J. P. Marques
Keyword(s):  
Likelihood Estimation ◽  
Star System ◽  
Current Estimate ◽  
Seismic Parameters ◽  
Fundamental Parameters ◽  
The Individual ◽  
The Masses ◽  
Stellar Masses ◽  
Triple Star ◽  
Orbital Analysis

Context. The NASA Kepler space telescope has detected solar-like oscillations in several hundreds of single stars, thereby providing a way to determine precise stellar parameters using asteroseismology. Aims. In this work, we aim to derive the fundamental parameters of a close triple star system, HD 188753, for which asteroseismic and astrometric observations allow independent measurements of stellar masses. Methods. We used six months of Kepler photometry available for HD 188753 to detect the oscillation envelopes of the two brightest stars. For each star, we extracted the individual mode frequencies by fitting the power spectrum using a maximum likelihood estimation approach. We then derived initial guesses of the stellar masses and ages based on two seismic parameters and on a characteristic frequency ratio, and modelled the two components independently with the stellar evolution code CESTAM. In addition, we derived the masses of the three stars by applying a Bayesian analysis to the position and radial-velocity measurements of the system. Results. Based on stellar modelling, the mean common age of the system is 10.8 ± 0.2 Gyr and the masses of the two seismic components are MA = 0.99 ± 0.01 M⊙ and MBa = 0.86 ± 0.01 M⊙. From the mass ratio of the close pair, MBb/MBa = 0.767 ± 0.006, the mass of the faintest star is MBb = 0.66 ± 0.01 M⊙ and the total seismic mass of the system is then Msyst = 2.51 ± 0.02 M⊙. This value agrees perfectly with the total mass derived from our orbital analysis, Msyst = 2.51−0.18+0.20 M⊙, and leads to the best current estimate of the parallax for the system, π = 21.9 ± 0.2 mas. In addition, the minimal relative inclination between the inner and outer orbits is 10.9° ± 1.5°, implying that the system does not have a coplanar configuration.

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