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Using a extended version of the Quantum Hadrodynamics (QHD), I propose a new microscopic equation of state (EoS) able to correctly reproduce the main properties of symmetric nuclear matter at the saturation density, as well produce massive neutron stars and satisfactory results for the radius and the tidal parameter $\Lambda$. I show that even when hyperons are present, this EoS is able to reproduce at least 2.00 solar masses neutron star. The constraints about the radius of a $2.00M_\odot$ and the minimum mass that enable direct Urca effect are also checked., Comment: 7 pages, 4 figures - Published version

Aiming at the weight problem of a light electric commercial vehicle, a lightweight optimization idea is proposed, which is based on the design of the frame structure made of TC4 titanium alloy. Taken the strength, stiffness and stability of the longitudinal beam as the boundary constraints, and the minimum mass of the frame longitudinal beam as the objective function, the mathematical model was established, and the longitudinal beam size was optimized by ant colony algorithm. The influence of different materials on the strength and stiffness of the frame was analyzed from the bending and torsion conditions. The finite element model of the frame before and after optimization was established in ANSYS, and the static conditions before and after optimization were compared and analyzed. The results show that: under the constraint conditions, the frame weight of TC4 material is reduced from 122kg before optimization to 103kg after optimization, which is 15.5% less than that before optimization, and the stress and deformation of the optimized frame meet the service conditions, which has great advantages for reducing the vehicle weight and realizing the lightweight purpose.

Many researchers are working in the field of pneumatic slurry transportation, where the rheological parameters involved in the flow. In the present work is a numerical simulation for the study of pressure drop of 30µm particle size of fly ash air mixture flow through a circular pipe was investigated through ANSYS Fluent. The present paper introduces a simplified 3-D Eulerian model along with RNG k-ε turbulent model. It was observed that the pressure drop was maximum for minimum mass flow rate of air and as the mass flow rate increases the pressure drop decreases and it becomes constant at a threshold mass flow rate for this particle size, which qualitatively matches with the experimental results observed by Bansal et al. (2013).

Based on the contact fatigue strength criterion of tooth surface, the mathematical model of gear ratio distribution of the electric vehicle is established. In the process, there are two objective functions. One is the minimum diameter of electric vehicle reducer, the other is the minimum mass of electric vehicle reducer. Through examples, relevant program is compiled with matlab software. It is obtained that there is a distribution method for gear ratio of the electric vehicle reducer.

In order to meet the needs of sludge dewatering treatment in urban areas, a screw extrusion filter with dynamic and static ring was designed. The spiral axis of the filter is simulated by finite element statics. Based on the simulation results, the structure of the spiral axis was topologically optimized, and the optimized mathematical model was established. The minimum mass was taken as the objective function, and the reasonable structure size of the spiral axis was obtained after optimization. Under the condition of satisfying the structural strength, its quality was reduced by 9.7%, and a good optimization effect was achieved.

The paper proposes an approach to the creation of an energy-efficient slow-moving linear magnetoelectric drive of a long-stroke single-stage piston compressor. The problem of optimal design of the magnetic system of the magnetoelectric motor of reciprocating action satisfying the criterion of the maximum of the developed electromagnetic force while ensuring the minimum mass of the active materials used is solved. A mathematical model for calculating the dynamics of a linear magnetoelectric drive is presented and the results of modeling dynamic starting characteristics are presented.

In this work we measure and study the cross-correlation signal between a foreground sample of GAMA galaxies with spectroscopic redshifts in the range $0.2, Comment: 31 pages, 9 figures, accepted version to be published in JCAP

Stars form from large clouds of gas and dust that contract under their own gravity. The birth of a star occurred when a fusion reaction of hydrogen into helium has ignited in its core. The key variable that determines the formation of a star is mass. If the mass of the contracting cloud is below certain minimum value, instead of a star, a substelar object -- known as a brown dwarf -- will form. How much mass is required for a star to form? This article aims to answer this question by means of a simple heuristic argument. The found value is 0.016 solar masses, which is of the same order of magnitude as the accepted value 0.08 solar masses. This article may be useful as pedagogical material in an introductory undergraduate astronomy course., 9 pages, 2 figures. Physics Education 2019

For ensuring the safety of battery pack and its enclosure, the mechanical design is crucial for generating lower deformation, lower stresses and vibrations during its actual operation. In addition, the minimum mass of battery pack is needed for lower energy consumption of pack. Therefore, the problem to be solved can be formulated as multi-objective optimization and much desire one for electric vehicle industry application. In this paper, the application of evolutionary approach of Genetic programming (GP) is illustrated for battery pack casing design considering the design requirements having higher mechanical performance. Data generated from finite element simulation was used as input in GP. The analysis concluded that the GP perform satisfactorily. GP models for three design outputs predicted the values in compare to actual values with errors RMSE and MAPE of .00154 and .00715, .000033 and 1.16, .52 and .48, respectively. These results can be used to design the battery pack enclosures. The similar models can be applied to different independent parameters to find out the possible relation in between them to correlate the results, find out the criticality of the individual parameter and then optimize the design accordingly.

The architectural design becomes an interdisciplinary process while the architectural forms, due to their various criteria, are more and more often created as a result of conducted optimization (simulated processes - "form follow process"). Activities that mimic the processes occurring in nature seem to be of particular interest. The inspirations with observed structures in nature shaped under the influence of loads acting on them constitute an interesting aspect of the search for optimization. The material and energy consumption were minimized through the evolution of structures and their adaptation to the environment. Therefore, such processes can serve as important patterns in the pursuit of building objects, effectively adapted to the location conditions, as an urban ecosystem element in accordance with the idea of sustainable development. In modern architecture, research is conducted using mathematical models in the search for optimal forms, based on the patterns of structures observed in nature. The article presents an analysis of a number of examples of bionic architecture in terms of structure and material. In addition, own model studies of selected bionic and geometrical structural forms were presented. The aim of the analysis at hand was to conduct optimization searches for the shaped bionic rod structures, selected due to the criterion of minimum mass. Among the analyzed structures, a noticeable effectiveness of forms transferred from nature was observed, which indicates the need for further research in this area.

We report the discovery of a substellar companion around the intermediatemass giant HD 175679. Precise radial velocity data of the star from Xinglong Station and Okayama Astrophysical Observatory (OAO) revealed a Keplerian velocity variation with an orbital period of 1366.8 \pm 5.7 days, a semiamplitude of 380.2 \pm 3.2m s.1, and an eccentricity of 0.378 \pm 0.008. Adopting a stellar mass of 2.7 \pm 0.3 M\odot, we obtain the minimum mass of the HD 175679 b is 37.3 \pm 2.8 MJ, and the semimajor axis is 3.36 \pm 0.12 AU. This discovery is the second brown dwarf companion candidate from a joint planet-search program between China and Japan., 10 pages, 3 figures, RAA accepted

The article describes a technique of determining the maximum accelerations of beam span structures arising from vibrations of the action of high-speed trains. The reliability of the proposed methodology is confirmed by the results of numerical modelling of the passage of high-speed trains on spans with different speeds. The proposed dynamic calculation algorithm is based on the connection between the maximum acceleration of a span, its stiffness and inertial characteristics, the length of the span and the parameters of a high-speed train. As a result of the research, requirements were received to limit the minimum mass of spans with the condition that the permissible vertical acceleration of the span is not exceeded (3.5 and 5.0 m / s2 for ballast and ballastless bridges). Based on the presented results, recommendations were developed for limiting the lower limit of the natural frequencies of oscillations of simple span structures, that are different from the recommendations of the International Union of Railways (UIC), designed for speeds less than 250 km/h and given in the Eurocode. The presented limitations of the lower limit of the natural frequencies of the oscillations of the span structures (10 to 30 m in length) make it possible to assign the main design parameters at the initial design stage in such a way as to minimize the dynamic impact of the mobile load at train speeds of up to 400 km/h. The proposed recommendations on the assignment of a minimum mass of span structures and the limitation of the lower limit of the natural frequencies of oscillations of simple span structures are of great importance and can be used in determining the main constructive parameters. Accounting for these recommendations significantly cuts the labor costs for de-sign and reduces the likelihood of possible adjustments after performing dynamic calculations.

FV CVn is a solar-type (G7) eclipsing binary whose analysis has so far been ignored. We observed it from 2014 January to 2018 May. The first photometric and orbital period investigation are presented here, combined with spectroscopic observations obtained by the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). The current preliminary solutions show that FV CVn is a new W-subtype contact binary with a mass ratio of q = M-2/M-1 = 2.44(+/- 0.20) and a temperature difference of Delta T = T-2 -T-1 similar or equal to -315 K. The orbital period investigation suggests that a cyclic variation of A = 0.0184(+/- 0.0034) days and P-3 = 17.65(+/- 0.076) years exists in FV CVn. This cyclic variation is analyzed for the light-travel-time effect (LTTE) via the presence of a third body with a minimum mass of M-3min = 0.73(+/- 0.018) M-circle dot, and an orbital semimajor axis shorter than 5.27(+/- 1.62) au. This is in agreement with the presence of a large quantity of a third light in the system. Photometric solutions suggest that the third body contributes about 26.4(+/- 6.3)% in R-c, and 29.0(+/- 5.9)% in I-c to the total light of the multiple system. The additional component may play an important role in the origin and evolution of central close binary. New radial velocities are needed in the future to check the accuracy of the absolute parameters.

We present radial velocity measurements of two stars observed as part of the Lick Subgiants Planet Search and the Keck N2K survey. Variations in the radial velocities of both stars reveal the presence of Jupiter-mass exoplanets in highly eccentric orbits. HD 16175 is a G0 subgiant from the Lick Subgiants Planet Search, orbited by a planet having a minimum mass of 4.4 M_Jup, in an eccentric (e = 0.59), 2.71 yr orbit. HD 96167 is a G5 subgiant from the N2K ("Next 2000") program at Keck Observatory, orbited by a planet having a minimum mass of 0.68 M_Jup, in an eccentric (e = 0.71), 1.366 yr orbit. Both stars are relatively massive (M_star = 1.3 M_sun) and are very metal rich ([Fe/H] > +0.3). We describe our methods for measuring the stars' radial velocity variations and photometric stability.

We present the photometric properties of the eclipsing binary TU Boo from detailed studies of the period and light variations, based on our new BVR observations and historical data collected from the literature. A total of 349 times of minimum light over 80 yr, including our four timings, were used for the period study. An analysis of the resulting O – C diagram reveals that the orbital period of TU Boo has varied in a quasi-sinusoidal way superposed on a long-term period decrease. The secular variation presumably indicates that mass is thermally transferred from the more massive primary star to its companion at a rate of about 7.24 × 10–8 M⊙ yr–1. The period and semiamplitude of the cyclical variation are 54.5 yr and 0.0177 days, respectively, which could be produced by either a light-time effect or a magnetic activity cycle. Our light curves are asymmetrical, with max I about 0.02-0.03 mag brighter than max II. Among possible spot models, the light variations were best-fit by using a two-spot model with both a cool spot and a hot spot on the secondary star. These may be formed by a combination of effects from a magnetic dynamo and mass transfer. We suggest that TU Boo is probably a triple system, consisting of a massive primary star with a spectral type of G3, a secondary component of spectral type G5-6, and a low-mass M-type tertiary companion with a minimum mass of about M3 = 0.34 M⊙.

We report precise Doppler measurements of GJ849 (M3.5V) that reveal the presence of a planet with a minimum mass of 0.82 Mjup in a 5.16 year orbit. At a = 2.35 AU, GJ849b is the first Doppler-detected planet discovered around an M dwarf to orbit beyond 0.21 AU, and is only the second Jupiter mass planet discovered around a star less massive than 0.5 Msun. This detection brings to 4 the number of M stars known to harbor planets. Based on the results of our survey of 1300 FGKM main--sequence stars we find that giant planets within 2.5 AU are ~3 times more common around GK stars than around M stars. Due to the GJ849's proximity of 8.8 pc, the planet's angular separation is 0."27, making this system a prime target for high--resolution imaging using adaptive optics and future space--borne missions such as the Space Interferometry Mission. We also find evidence of a linear trend in the velocity time series, which may be indicative of an additional planetary companion.

In this paper, a new method for the determination of optimum parameters of open-cycle liquid-propellant engine of launch vehicles is introduced. The parameters affecting the objective function, which is the ratio of specific impulse to gross mass of the launch vehicle, are chosen to achieve maximum specific impulse as well as minimum mass for the structure of engine, tanks, etc. The proposed algorithm uses constant integration of thrust with respect to time for launch vehicle with specific diameter and length to calculate the optimum working condition. The results by this novel algorithm are compared to those obtained from using Genetic Algorithm method and they are also validated against the results of existing launch vehicle.

The dynamical nature of the fluid motion in very low-mass and brown dwarf stars indicates that the magnetic field has to be generated in these objects by dynamo action. Pressure in these stars is supported partially by non-relativistic degenerate electrons. It was established that the magnetic field can act on degenerate gas produces pressure anisotropy. Also anisotropy can be generated in rotating stars. Hence magnetic field and rotation may be considered as a source of anisotropy in such stars. This paper addresses the effect of anisotropy in the minimum mass of hydrogen burning and in brown dwarf stars. The results show that the minimum mass of the star needs to be increased to reach the stability condition due to the existence of pressure anisotropy and there was a change in the mass-radius relation for that stars.

Extreme mass ratio close binaries of W UMa-type represent an interesting class of objects in which ~1M⊙ main-sequence star is in contact with a significantly less massive companion (M2 ~ 0.1M⊙). Earlier theoretical investigations of these systems found that there is a minimum mass ratio q = M2/M1 ≈ 0.085 - 0.095 (obtained for n = 3 polytrope–fully radiative primary) above which these systems are stable. If the mass ratio is lower than minimum, a tidal instability develops (Darwin's instability). This instability, which is secular, growing on a viscous dissipation timescale, eventually forces the stars to merge into a single, rapidly rotating object (such as FK Com-type stars or blue stragglers), implying that such systems would not be observed. There appear to be, however, some W UMa-type binaries with empirically obtained q values below the theoretical limit for stability. The aim of this dissertation was to try to resolve the discrepancy between theory and observations by considering rotating polytropes. Other candidate systems for stellar mergers such as AM CVn-type stars have also been discussed in the dissertation.

Most of our knowledge of planets orbiting nearby stars comes from Doppler surveys. For spaced-based, high-contrast imaging missions, nearby stars with Doppler-discovered planets are attractive targets. The known orbits tell imaging missions where and when to observe, and the dynamically-determined masses provide important constraints for the interpretation of planetary spectra. Quantifying the set of planet masses and orbits that could have been detected will enable more efficient planet discovery and characterization. We analyzed Doppler measurements from Lick and Keck Observatories collected by the California Planet Survey. We focused on stars that are likely targets for three space-based planet imaging mission concepts studied by NASA--WFIRST-AFTA, Exo-C, and Exo-S. The Doppler targets are primarily F8 and later main sequence stars, with observations spanning 1987-2014. We identified 76 stars with Doppler measurements from the prospective mission target lists. We developed an automated planet search and a methodology to estimate the pipeline completeness using injection and recovery tests. We applied this machinery to the Doppler data and computed planet detection limits for each star as a function of planet minimum mass and semi-major axis. For typical stars in the survey, we are sensitive to approximately Saturn-mass planets inside of 1 AU, Jupiter-mass planets inside of ~3 AU, and our sensitivity declines out to ~10 AU. For the best Doppler targets, we are sensitive to Neptune-mass planets in 3 AU orbits. Using an idealized model of Doppler survey completeness, we forecast the precision of future surveys of non-ideal Doppler targets that are likely targets of imaging missions., Comment: Accepted to PASP, 125 pages, 89 figures, Machine-readable data products are available at http://exoplanetarchive.ipac.caltech.edu/docs/contributed_data.html

All available mid-eclipse times of the eclipsing binary Z Draconis are analyzed, and three sets of cyclic variations with periods of 20.1, 29.96 and 59.88 yr are found. The low-amplitude variations with a period of 20.1 yr may be attributed to the unavoidable slight imperfection in the double-Keplerian model, which gives periods of 29.96 and 59.88 yr. Interestingly, the Z Draconis system is close to a 2:1 mean-motion resonance, or a 6:3:2 mean-motion resonance if the 20.1 yr period really exists. We also find that the best solutions tend to give the minimum eccentricities. Based on Kepler’s third law, the outermost companion has a minimum mass of ~ 0.77 M ⊙ , whereas the middle companion is an M dwarf star with a mass of ~ 0.40 M ⊙ , suggesting that Z Draconis is a general N-body system.

It is suggested that black holes have a minimum mass of the order of the Planck mass, mPl. This limit gives rise to limits for other black-hole parameters. It is shown that the limits derived can sometimes be more general in their applicability, and that black holes can be used as a device to obtain limits on physical quantities in a wider context. This is, in part, a consequence of the approximate application of the Principle of Equivalence. As an example in dynamics, the maximum acceleration of a free particle is treated, and this is related to what the authors call the 'Planck acceleration'; while in thermodynamics, arguments are given concerning the entropy/energy ratio for physical systems. It is concluded that only a black-hole minimum mass approximately mPl can give the remarkable self-consistency that exists between all the limits discussed.

We report high-resolution optical spectroscopy of the low-mass X-ray binary V395 Car/2S 0921-630 obtained with the MIKE echelle spectrograph on the Magellan-Clay telescope. Our spectra are obtained near superior conjunction of the mass donor star and we exploit the absorption lines originating from the back-side of the K-type object to accurately derive its rotational velocity. Using K0-K1 III templates, we find vsini=32.9 +/- 0.8 km/s. We show that the choice of template star and the assumed limb darkening coefficient has little impact on the derived rotational velocity. This value is a significant revision downwards compared to previously published values. We derive new system parameter constraints in the light of our much lower rotational velocity. We find M_1=1.44 +/- 0.10 Msun, M_2=0.35 +/- 0.03 Msun, and q=0.24 +/- 0.02 where the errors have been estimated through a Monte-Carlo simulation. A possible remaining systematic effect is the fact that we may be over-estimating the orbital velocity of the mass donor due to irradiation effects. However, any correction for this effect will only reduce the compact object mass further, down to a minimum mass of M_1=1.05 +/- 0.08 Msun. There is thus strong evidence that the compact object in this binary is a neutron star of rather typical mass and that the previously reported mass values of 2-4Msun were too high due to an over-estimate of the rotational broadening., 4 pages, 3 figures, accepted for publication in ApJ Letters

Truss structures are widely used for the support of structural loads in applications where minimum mass solutions are required. Their nodes are normally constructed to resist rotation to maximize their stiffness under load. A multi-link node concept has recently been proposed that permits independent rotation of tetrahedral trusses linked by such a joint. High authority shape morphing truss structures can therefore be designed by the installation of linear displacement actuators within the truss mechanisms. Examples of actuated structures with either linear or planar shapes are presented and their ability to bend, twist and undulate is demonstrated. An experimental device has been constructed using one-way shape memory wire actuators in antagonistic configurations that permit reversible actuated structures. It is shown that the actuated structure displacement response is significantly amplified by use of a mechanically magnified design.

Minimum-mass target is an effective way to control debris produced during 13.5 nm EUV emission. In this work, we introduce a new method to fabricate 500 ?m PVA air bubbles which is the supporting medium for tin layer using our home-made apparatus. We found that the thinner needle could produce smaller PVA bubbles at a stirring speed of > 420 rpm and the air bubbles were found to be stable more than 40 min which satisfies the requirement of EUV target. Tin elements were assembled on the PVA air bubbles and the presence of tin was confirmed by ICP experiment. The stability of the PVA air bubbles shows that they could be used as EUV emission target in the future.

Two nearby M dwarfs, CC 1228 and Wolf 922, give indication of duplicity from plates taken with the Sproul 61-cm refractor. The unseen companions cause a perturbation for CC 1228 with P = 6.3y and for Wolf 922 with P = 1.93y. The interpretation leads to a minimum mass of 0.02 solar mass for CC 1228B and a likely range in mass of 0.13-0.20 solar mass for Wolf 922B. Accurate parallaxes yield distances of 12.2 parsecs for CC 1228 and 8.2 parsec for Wolf 922.

Models of AGB evolution of intermediate mass stars are constructed that take into account overshooting by extrapolating models by Bertelli et al. (1985). Models with overshooting show an increased importance of second dredge-up compared with standard models. He production is increased, allowing dY/dZ to increase by roughly 0.7. Secondary N production is also increased in a way that can explain the observed N/O versus O diagram. Overshooting decreases the theoretical minimum mass for the formation of type I planetary nebulae (PN) down to roughly 2.6 solar masses, in good agreement with the observed value of 2.4 solar masses. Other effects of overshooting in type I PN are He/H abundances as high as 0.22 and higher depletion of O.

The nearby M3 V star CC 20,986, shows a perturbation from astrometric plates taken with the 61-cm Sproul refractor. The interpretation indicates an unseen companion revolving about the visible component in a period of 3.r72 with a likely range in minimum mass of 0.06 to 0.08 'At . Key words: astrometric binary-parallax