scholarly journals An approach to confirm the existence of a black hole

2021 ◽  
Author(s):  
Junjin Huang ◽  
Chanyuk Lam David ◽  
Qiuyun Liu
Keyword(s):  
Black Hole ◽  
Large Mass ◽  
Small Mass ◽  
The Earth ◽  
Acceleration And Deceleration

Solar and lunar gravitational pulls prompt slower accelerations of large mass or faster accelerations of small mass on the Earth. Gravitation-triggered acceleration and deceleration is the cause of volcanoes, earthquakes, sunspots and starspots. Starspots in neighboring stars can thus be used as the indication for the existence of a black hole.

scholarly journals Vortex-Induced Vibration: the slower deceleration of the west bank leads to the shortening of the Humen Bridge in Guangdong, China

2020 ◽  
Author(s):  
Haili Ran ◽  
Xiaoyong Lu ◽  
Ruohan Zheng ◽  
Cui Yang ◽  
Qiuyun Liu
Keyword(s):  
Potential Energy ◽  
Civil Engineering ◽  
West Bank ◽  
Large Mass ◽  
Small Mass ◽  
The West ◽  
Vortex Induced Vibration ◽  
Gravitational Fields ◽  
The Earth ◽  
Engineering Projects

The Earth self-rotates in the solar and lunar gravitational fields. According to Newton’s Law of Inertia, large mass accelerates and decelerates more slowly than smaller masses, whereas small mass accelerates and decelerates more quickly than larger mass, which gives rise to stress when potential energy is present, damaging civil engineering projects. Humen Bridge of Guangdong, China and two century-old dams in Michigan which were affected recently can be explained by this theory.

scholarly journals Resection of primary cardiac angiosarcoma infiltrating the right atrioventricular junction and tricuspid valve: a case report

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Lubna Bakr ◽  
Hussam AlKhalaf ◽  
Ahmad Takriti
Keyword(s):  
Surgical Resection ◽  
Tricuspid Valve ◽  
Right Atrium ◽  
Large Mass ◽  
Small Mass ◽  
Malignant Tumours ◽  
Atrioventricular Junction ◽  
Cardiac Angiosarcoma ◽  
Complete Surgical Resection ◽  
The Right

Abstract Background Primary cardiac tumours are extremely rare. Most of them are benign. Sarcomas account for 95% of the malignant tumours. Prognosis of primary cardiac angiosarcoma remains poor. Complete surgical resection is oftentimes hampered when there is extensive tumour involvement into important cardiac apparatus. We report a case of cardiac angiosarcoma of the right atrium and ventricle, infiltrating the right atrioventricular junction and tricuspid valve. Case presentation Initially, a 22-year-old man presented with dyspnoea. One year later, he had recurrent pericardial effusion. Afterwards, echocardiography revealed a large mass in the right atrium, expanding from the roof of the right atrium to the tricuspid valve. The mass was causing compression on the tricuspid valve, and another mass was seen in the right ventricle. Complete resection of the tumour was impossible. The mass was resected with the biggest possible margins. The right atrium was reconstructed using heterologous pericardium. The patient’s postoperative course was uneventful. Postoperative echocardiography showed a small mass remaining in the right side of the heart. Histopathology and immunohistochemistry confirmed the diagnosis of angiosarcoma. The patient underwent adjuvant chemotherapy and radiotherapy later on. He survived for 1 year and 5 days after the surgery. After a diagnosis of lung and brain metastases, he ended up on mechanical ventilation for 48 h and died. Conclusions Surgical resection combined with postoperative chemotherapy and radiotherapy is feasible even in patients with an advanced stage of cardiac angiosarcoma when it is impossible to perform complete surgical resection.

scholarly journals Probing within the bondi radius of the ultramassive black hole in NGC 1600

2021 ◽  
Author(s):  
J Runge ◽  
S A Walker
Keyword(s):  
Black Hole ◽  
Accretion Rate ◽  
Statistical Significance ◽  
Large Mass ◽  
Nearby Galaxy ◽  
Density Profiles ◽  
Spatially Resolved ◽  
Single Temperature ◽  
Slight Rise ◽  
Two Temperature

Abstract We present deep (250 ks) Chandra observations of the nearby galaxy group NGC 1600, which has at its centre an ultramassive black hole (17±1.5 billion M⊙). The exceptionally large mass of the black hole coupled with its low redshift makes it one of only a handful of black holes for which spatially resolved temperature and density profiles can be obtained within the Bondi radius with the high spatial resolution of Chandra. We analyzed the hot gas properties within the Bondi accretion radius R$_\rm {B}=1{_{.}^{\prime\prime}} 2 - 1{_{.}^{\prime\prime}} 7= 0.38 - 0.54~\rm {kpc}$. Within a ∼3 kpc radius, we find two temperature components with statistical significance. Both the single temperature and two temperature models show only a very slight rise in temperature towards the centre, and are consistent with being flat. This is in contrast with the expectation from Bondi accretion for a temperature profile which increases towards the centre, and appears to indicate that the dynamics of the gas are not being determined by the central black hole. The density profile follows a relatively shallow ρ∝ r−[0.61 ± 0.13] relationship within the Bondi radius, which suggests that the true accretion rate on to the black hole may be lower than the classical Bondi accretion rate.

scholarly journals Forming bulges during galaxy minor mergers

2007 ◽  
Vol 3 (S245) ◽  
pp. 63-66 ◽  
Author(s):  
T. J. Cox ◽  
J. Younger ◽  
L. Hernquist ◽  
P. F. Hopkins
Keyword(s):  
Black Hole ◽  
Large Mass ◽  
Elliptical Galaxies ◽  
Equal Mass ◽  
Mass Ratio ◽  
Black Hole Growth ◽  
Major Merger ◽  
Hole Growth ◽  
Minor Mergers ◽  
Large Mass Ratio

AbstractThe hierarchical formation of structure suggests that dark halos, and the galaxies they host, are shaped by their merging history. While the idea that mergers between galaxies of equal mass, i.e., major merger, produce elliptical galaxies has received considerable attention, he galaxies that result from minor merger, i.e., mergers between galaxies with a large mass ratio, is much less understood. We have performed a large number of numerical simulations of minor mergers, including cooling, star formation, and black hole growth in order to study this process in more detail. This talk will present some preliminary results of this study, and in particular, the morphology and kinematics of minor merger remnants.

INFLUENCE OF MAGNETIC CHARGE ON THE SAGNAC EFFECT IN THE BARDEEN SPACETIME

2021 ◽  
Vol 0 (1) ◽  
pp. 92-96
Author(s):  
R.KH. KARIMOV ◽  
◽  
K.K. NANDI ◽  
Keyword(s):  
Black Hole ◽  
Light Source ◽  
Magnetic Charge ◽  
Sagnac Effect ◽  
Modified Theories Of Gravity ◽  
Circular Orbits ◽  
The Earth ◽  
Astrophysical Objects ◽  
Interesting Task ◽  
Theories Of Gravity

This paper investigates one of the most interesting effects associated with the rotation of astrophysical objects (the Sagnac effect). The effect was first confirmed in laboratory experiments by Georges Sagnac with a rotating ring interferometer in 1913. Later, the effect was also confirmed within the framework of the Earth in the "Around-the-World" experiment conducted by J. Hafele and R. Kitting, in which they twice circled the Earth with an atomic cesium clock on board and compared the "flying" clock with those remaining static on the Earth. As a result, a non-zero difference in the clock rate was found as a confirmation of the Sagnac effect. Subsequently, more precise satellite experiments have been carried out to measure the Sagnac effect within the Earth. The effect was also considered in general relativity and modified theories of gravity, where many works were carried out to study the influence of such parameters as angular momentum, cosmological constant, Ricci scalar, etc. on the Sagnac effect. An interesting task is to study the influence of a magnetic charge on the effect, since the solution with rotation described by a black hole with mass M and magnetic charge g is the Bardeen nonsingular black hole. The work will calculate the Sagnac effect in the space-time of the rotating Bardeen black hole for both geodesic and non-geodesic circular orbits of the light source / receiver (assuming that the light source and receiver are defined at the same point). Two types of circular orbits describe the opposing influence on the Sagnac effect: the Sagnac delay increases with an increase in the magnetic charge in the case of non-geodesic circular orbits and decreases in the case of geodesic circular orbits. However, the farther is the orbit of the light source / receiver, the less the magnetic charge affects the Sagnac delay. It is also assumed that the gravity of the Earth and the Sun near the surface is well described by the Bardeen metric.

scholarly journals A multi-component SIMP model with U(1)X → Z2 × Z3

2021 ◽  
Vol 2021 (9) ◽  
Author(s):  
Soo-Min Choi ◽  
Jinsu Kim ◽  
Pyungwon Ko ◽  
Jinmian Li
Keyword(s):  
Dark Matter ◽  
Gauge Symmetry ◽  
Mass Difference ◽  
Massive Particle ◽  
Large Mass ◽  
Small Mass ◽  
Dark Matter Candidate ◽  
Mass Hierarchy ◽  
New Class ◽  
Matter Fields

Abstract Multi-component dark matter scenarios are studied in the model with U(1)X dark gauge symmetry that is broken into its product subgroup Z2 × Z3 á la Krauss-Wilczek mechanism. In this setup, there exist two types of dark matter fields, X and Y, distinguished by different Z2 × Z3 charges. The real and imaginary parts of the Z2-charged field, XR and XI, get different masses from the U(1)X symmetry breaking. The field Y, which is another dark matter candidate due to the unbroken Z3 symmetry, belongs to the Strongly Interacting Massive Particle (SIMP)-type dark matter. Both XI and XR may contribute to Y’s 3 → 2 annihilation processes, opening a new class of SIMP models with a local dark gauge symmetry. Depending on the mass difference between XI and XR, we have either two-component or three-component dark matter scenarios. In particular two- or three-component SIMP scenarios can be realised not only for small mass difference between X and Y, but also for large mass hierarchy between them, which is a new and unique feature of the present model. We consider both theoretical and experimental constraints, and present four case studies of the multi-component dark matter scenarios.

Experimental determination of bulk dielectric properties and porosity of porous asphalt and soils using GPR and a cyclic moisture variation technique

Geophysics ◽  
2006 ◽  
Vol 71 (4) ◽  
pp. K93-K102 ◽  
Author(s):  
W. L. Lai ◽  
W. F. Tsang ◽  
H. Fang ◽  
D. Xiao
Keyword(s):  
Water Saturation ◽  
Complex Refractive Index ◽  
Large Mass ◽  
Small Mass ◽  
Time Domain Reflectometry ◽  
Water Permeation ◽  
Moisture Variation ◽  
Wide Range ◽  
Test Materials ◽  
Variation Technique

This paper describes a new method for determining porosities in two porous construction and geologic materials (asphalt and soil) by using ground-penetrating radar (GPR) over a wide range of controlled degrees of water saturation [Formula: see text]. We call this method a cyclic moisture variation technique (CMVT). Freshwater is used as an enhancer or a tracer to allow GPR to easily detect and differentiate amounts of water or other moisture in these materials. The CMVT is based on measuring the changes of real permittivity [Formula: see text] and [Formula: see text] in the test materials as they transition from partially saturated states to a fully saturated state via cycles of water permeation and dewatering. This method does not disturb the test materials, as do the methods associated with traditional laboratory testing on cored samples. It also tests a large mass of in situ material, compared with the small mass tested by the conventional or electromagnetic coaxial transmission line (EMCTL) method (also known as a dielectric cell) and the time-domain reflectometry (TDR) method. Porosity values of asphalt [Formula: see text] and of soils [Formula: see text] were determined by fitting the data into the complex refractive index model (CRIM). Dielectric hysteresis of both soils and asphalt also is observable during the tests and shows that the pathways of water-ingress and water-egress processes are not identical in the plot of [Formula: see text] versus degrees of water saturation [Formula: see text].

scholarly journals Periodic self-reformation of rippled perpendicular collisionless shocks in two dimensions

2018 ◽  
Vol 36 (4) ◽  
pp. 1047-1055 ◽  
Author(s):  
Takayuki Umeda ◽  
Yuki Daicho
Keyword(s):  
Magnetic Field ◽  
Shock Front ◽  
Large Scale ◽  
Large Mass ◽  
Small Mass ◽  
Two Dimensions ◽  
Electron Mass ◽  
The Reformation ◽  
Ion Cyclotron ◽  
Mass Ratios

Abstract. Large-scale two-dimensional (2-D) full particle-in-cell (PIC) simulations are carried out for studying periodic self-reformation of a supercritical collisionless perpendicular shock with an Alfvén–Mach number MA∼6. Previous self-consistent one-dimensional (1-D) hybrid and full PIC simulations have demonstrated that the periodic reflection of upstream ions at the shock front is responsible for the formation and vanishing of the shock-foot region on a timescale of the local ion cyclotron period, which was defined as the reformation of (quasi-)perpendicular shocks. The present 2-D full PIC simulations with different ion-to-electron mass ratios show that the dynamics at the shock front is strongly modified by large-amplitude ion-scale fluctuations at the shock overshoot, which are known as ripples. In the run with a small mass ratio, the simultaneous enhancement of the shock magnetic field and the reflected ions take place quasi-periodically, which is identified as the reformation. In the runs with large mass ratios, the simultaneous enhancement of the shock magnetic field and the reflected ions occur randomly in time, and the shock magnetic field is enhanced on a timescale much shorter than the ion cyclotron period. These results indicate a coupling between the shock-front ripples and electromagnetic microinstabilities in the foot region in the runs with large mass ratios. Keywords. Space plasma physics (wave–particle interactions)

DECIGO PATHFINDER

2013 ◽  
Vol 22 (01) ◽  
pp. 1341002 ◽  
Author(s):  
MASAKI ANDO ◽  
the DECIGO WORKING GROUP
Keyword(s):  
Black Hole ◽  
Gravitational Wave ◽  
Conceptual Design ◽  
High Precision ◽  
Precision Measurements ◽  
Current Status ◽  
The Earth ◽  
Future Space

DECIGO Pathfinder (DPF) is a small (~350 kg) satellite orbiting the Earth. DPF was originally proposed as the first milestone mission for a future space gravitational-wave (GW) antenna, DECi-hertz Interferometer Gravitational wave Observatory (DECIGO). In addition to the purpose of space demonstrations for DECIGO, DPF has scientific objectives: observation of GWs from black-hole mergers and monitor of Earth's gravity, as well as establishment of space technologies for high-precision measurements. In this paper, we review the conceptual design, scientific outcomes and the current status of DPF.

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