scholarly journals Technical issues in a spherical system coupled with isotropic matter distribution and the horizon problem with higher curvature quantities

2016 ◽  
Vol 94 (11) ◽  
pp. 1216-1221 ◽  
Author(s):  
T. Hussain ◽  
M. Khurshudyan
Keyword(s):  
Equations Of Motion ◽  
Matter Content ◽  
Matter Distribution ◽  
Technical Issue ◽  
Time Duration ◽  
Spherical System ◽  
Exterior Region ◽  
Horizon Problem ◽  
Technical Issues ◽  
Total Matter

In this paper, we explore some technical issue in the study of a spherical system coupled with isotropic matter distribution. We also study the horizon problem under the influence of higher curvature quantities. We evaluate well-known equations of motion. We also join the exterior region with an interior one by taking the well-known matching conditions. We first find total matter content within the system and then calculate black hole and cosmological horizons. We have developed a technique for determining some dynamical variables that are involved in controlling the time duration of the emergence of horizons as well as singularities.

scholarly journals Does the Cosmological Expansion Change Local Dynamics?

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1417
Author(s):  
Marcelo Schiffer
Keyword(s):  
Dark Matter ◽  
Modified Gravity ◽  
Hubble Constant ◽  
Matter Content ◽  
Matter Distribution ◽  
Present Value ◽  
Field Equations ◽  
Local Dynamics ◽  
Cosmological Expansion ◽  
Modified Gravity Theories

It is a well-known fact that the Newtonian description of dynamics within Galaxies for its known matter content is in disagreement with the observations as the acceleration approaches a0≈1.2×10−10 m/s2 (slighter larger for clusters). Both the Dark Matter scenario and Modified Gravity Theories (MGT) fail to explain the existence of such an acceleration scale. Motivated by the closeness of the acceleration scale and the Hubble constant cH0≈10−9 h m/s2, we are led to analyze whether this coincidence might have a Cosmological origin for scalar-tensor and spinor-tensor theories by performing detailed calculations for perturbations that represent the local matter distribution on the top of the cosmological background. Then, we solve the field equations for these perturbations in a power series in the present value of the Hubble constant. As we shall see, for both theories, the power expansion contains only even powers in the Hubble constant, a fact that renders the cosmological expansion irrelevant for the local dynamics.

Technical Issues on Seismic Design of Nuclear Piping Systems

2007 ◽  
Author(s):  
Gerry C. Slagis
Keyword(s):  
Seismic Design ◽  
Seismic Event ◽  
Seismic Loads ◽  
Significant Issue ◽  
Technical Issue ◽  
Piping Systems ◽  
Technical Issues ◽  
Design Requirements ◽  
Seismic Stress ◽  
Effective Design

The design of nuclear piping systems has evolved significantly since the first Section III plants were constructed in the early 70s. Effective design to accommodate seismic loads is the dominant problem in the industry. The Section III code committee has been working since the late 80s to develop new seismic stress limits. Code revisions were incorporated in 1994, but to date, have not been accepted by NRC. Hence, appropriate piping seismic stress limits is one very significant technical issue. A second significant issue is revisions to seismic design requirements in 10CFR50 that NRC has made. It is now acceptable to design only for SSE loads, if the plant is shut down for inspection for a seismic event of equal to or greater than 1/3 the SSE. A third issue is whether the amplified response levels required for modern designs are reasonable and appropriate. The purpose of this paper is to explore these three issues. Recommendations are provided.

scholarly journals Imprint of Pressure on Characteristic Dark Matter Profiles: The Case of ESO0140040

Galaxies ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 74
Author(s):  
Kuantay Boshkayev ◽  
Talgar Konysbayev ◽  
Ergali Kurmanov ◽  
Orlando Luongo ◽  
Marco Muccino
Keyword(s):  
Dark Matter ◽  
Complex Structure ◽  
Matter Content ◽  
Model Parameters ◽  
Matter Distribution ◽  
Density Profiles ◽  
The Galaxy ◽  
Dark Matter Distribution ◽  
Observational Signature

We investigate the dark matter distribution in the spiral galaxy ESO0140040, employing the most widely used density profiles: the pseudo-isothermal, exponential sphere, Burkert, Navarro-Frenk-White, Moore and Einasto profiles. We infer the model parameters and estimate the total dark matter content from the rotation curve data. For simplicity, we assume that dark matter distribution is spherically symmetric without accounting for the complex structure of the galaxy. Our predictions are compared with previous results and the fitted parameters are statistically confronted for each profile. We thus show that although one does not include the galaxy structure it is possible to account for the same dynamics assuming that dark matter provides a non-zero pressure in the Newtonian approximation. In this respect, we solve the hydrostatic equilibrium equation and construct the dark matter pressure as a function for each profile. Consequently, we discuss the dark matter equation of state and calculate the speed of sound in dark matter. Furthermore, we interpret our results in view of our approach and we discuss the role of the refractive index as an observational signature to discriminate between our approach and the standard one.

scholarly journals Effect of harvest period on foliage production and dry matter distribution in five cassava cultivars during the second plant cycle

2006 ◽  
Vol 49 (6) ◽  
pp. 1007-1018 ◽  
Author(s):  
Edvaldo Sagrilo ◽  
Pedro Soares Vidigal Filho ◽  
Manoel Genildo Pequeno ◽  
Maria Celeste Gonçalves Vidigal ◽  
Carlos Alberto Scapim ◽  
...  
Keyword(s):  
Dry Matter ◽  
Rest Period ◽  
Matter Content ◽  
Plant Production ◽  
Dry Matter Content ◽  
Matter Distribution ◽  
Storage Roots ◽  
Leaf Production ◽  
Dry Matter Distribution ◽  
Cassava Plant

The objective of this work was to study the leaf production pattern and dry matter distribution in cassava during the second plant cycle. The completely randomized experimental design with four replications was used, with five cultivars in the main plots and ten harvest times in the sub-plots. Foliage production was affected by plant age, being higher in hot periods. Leaf blades and petioles dry matter content presented a linear increase due to a progressive decrease in the amount of young leaves and ontogenetic factors. The stems provided, temporarily, carbohydrates to the plant re-growth, delaying the availability and use of storage roots dry matter. The dry matter content in the storage roots was lower during the vegetative and higher during rest period. The storage roots diameter increased considerably when the amount of leaves was higher, indicating the importance of leaf area in the cassava plant production.

Effects of non-vanishing dark matter pressure in the Milky Way Galaxy

2021 ◽  
Vol 508 (1) ◽  
pp. 1543-1554
Author(s):  
K Boshkayev ◽  
T Konysbayev ◽  
E Kurmanov ◽  
O Luongo ◽  
D Malafarina ◽  
...  
Keyword(s):  
Black Hole ◽  
Dark Matter ◽  
Gravitational Lensing ◽  
Matter Content ◽  
Dark Matter Halo ◽  
Matter Distribution ◽  
Milky Way Galaxy ◽  
The Galaxy ◽  
Dark Matter Distribution ◽  
Inner Parts

ABSTRACT We consider the possibility that the Milky Way’s dark matter halo possesses a non-vanishing equation of state. Consequently, we evaluate the contribution due to the speed of sound, assuming that the dark matter content of the galaxy behaves like a fluid with pressure. In particular, we model the dark matter distribution via an exponential sphere profile in the galactic core, and inner parts of the galaxy whereas we compare the exponential sphere with three widely used profiles for the halo, i.e. the Einasto, Burkert and Isothermal profile. For the galactic core, we also compare the effects due to a dark matter distribution without black hole with the case of a supermassive black hole in vacuum and show that present observations are unable to distinguish them. Finally we investigate the expected experimental signature provided by gravitational lensing due to the presence of dark matter in the core.

What Is a “Known and Established” Standard?

2018 ◽  
Author(s):  
Samuel Miranda
Keyword(s):  
Federal Regulations ◽  
Technical Issue ◽  
Technical Issues

The NRC staff, and licensees will sometimes cite a Known and Established Standard, especially when there is evidence that the staff’s position, with respect to a Known and Established Standard, may have changed. Licensees will often flag such changes as backfits, and demand that they meet the requirements of the Backfit Rule in the Code of Federal Regulations (10 CFR §50.109). However, the term, Known and Established Standard, is not clearly defined. If the term is not defined by the NRC staff, then it’s possible that it will be defined by others, most notably by licensees with technical issues or license amendment requests (LARs) that are undergoing the staff’s review. What follows is a discussion of the origin and application of the NRC’s Known and Established Standard, and how it might be defined. The Known and Established Standard is first deconstructed into its two components, Known and Established, and then each is defined separately. When this is done, it becomes apparent that some Known and Established Standards can be more important than others. The two definitions can be used, together, to distinguish between unequal, even incompatible Known and Established Standards. This could help the NRC staff identify the most relevant Known and Established Standard to apply in its review or evaluation of a particular technical issue or license amendment request (LAR). Simply choosing the most recent of Known and Established Standards might not be adequate.

scholarly journals Dark matter distribution and dynamics of dwarf spheroidal galaxies

2019 ◽  
Vol 14 (S353) ◽  
pp. 239-245
Author(s):  
Ewa L. Łokas
Keyword(s):  
Dark Matter ◽  
Velocity Dispersion ◽  
Matter Content ◽  
Current Status ◽  
Superposition Method ◽  
Matter Distribution ◽  
Dwarf Spheroidal Galaxies ◽  
Dark Matter Distribution ◽  
Dynamical Modelling ◽  
Spheroidal Galaxies

AbstractI review the current status of dynamical modelling of dwarf spheroidal galaxies focusing on estimates of their dark matter content. Starting with the simplest methods using the velocity dispersion profiles I discuss the inherent issues of mass-anisotropy degeneracy and contamination by unbound stars. I then move on to methods of increasing complexity, aiming to break the degeneracy, up to recent applications of the Schwarzschild orbit superposition method. The dynamical modelling is placed in the context of possible scenarios for the formation of dwarf spheroidal galaxies, including the tidal stirring model and mergers of dwarf galaxies. The two scenarios are illustrated with examples from simulations: a comparison between the tidal evolution of dwarfs with cuspy and cored dark matter profiles and the formation of a dwarf spheroidal with prolate rotation.

scholarly journals Financial Implications of Femtocell Deployment

2018 ◽  
Vol 227 ◽  
pp. 03006 ◽  
Author(s):  
Jana Zausinová ◽  
Martin Zoričak ◽  
Gabriel Bugár ◽  
Juraj Gazda
Keyword(s):  
Heterogeneous Networks ◽  
Modern Concept ◽  
Pricing Strategies ◽  
Economic Aspects ◽  
Allocation Mechanism ◽  
Technical Issue ◽  
Agent Based ◽  
Technical Issues ◽  
Data Transfers ◽  
Increasing Demand

Increased usage in wireless communication has been observed in the last decades and it is expected to rise even more. Traditional spectrum allocation mechanism together with increasing demand for data transfers caused spectrum to become more congested. As a consequence, high pressure for its more effective usage emerges. Modern concept of heterogeneous networks with cognitive femtocells represents one of the promising solutions. Associated technical issues of heterogeneous networks have been discussed in many papers. However, economic aspects of femtocell deployment in network are still insufficiently analysed. This paper is devoted to economic aspects of operators’ behaviour in the macro-femto network but we also focus on technical issue of overall spectrum usage. For this purpose, the agent-based model of two-tier network was proposed. Results of simulation confirm significant influence of number of deployed femtocells and their location in the network on operators’ pricing strategies and their whole economic performance.

scholarly journals STIFFENED PLATES SUBJECTED TO UNIFORM BLAST LOADING/IŠSKIRSTYTĄJA SPROGIMO APKROVA VEIKIAMOS SUSTANDINTOS PLOKŠTĖS

2008 ◽  
Vol 14 (3) ◽  
pp. 155-161 ◽  
Author(s):  
Abdelkrim Kadid
Keyword(s):  
Numerical Solutions ◽  
Equations Of Motion ◽  
Linear Equations ◽  
Time Integration ◽  
Blast Loading ◽  
Rate Sensitivity ◽  
Stiffened Plates ◽  
Time Duration ◽  
Central Difference ◽  
Plastic Strain Energy

An investigation has been carried out to examine the behaviour of stiffened plates subjected to uniform blast loading. The aim of this work is to determine the dynamic response of the plates with different stiffener configurations and consider the effect of mesh dependency, loading duration, and strain‐rate sensitivity. Numerical solutions are obtained by using the finite element method and the central difference method for the time integration of the non‐linear equations of motion. Special emphasis is focused on the evolution of mid‐point displacements, and plastic strain energy. The results obtained allow an insight into the effect of stiffener configurations and of the above parameters on the response of the plates under uniform blast loading and indicate that stiffener configurations and time duration can affect their overall behaviour. Santrauka Atlikta išskirstytąja sprogimo apkrova veikiamų sustandintų plokščių elgsenos analizė. Šio darbo tikslas – atlikti plokščių dinaminės elgsenos analizę, esant skirtingam sąstandų išdėstymui bei įvertinant baigtinių elementų tinklo, apkrovimo trukmės ir deformacijų pokyčio jautrumo įtaką skaičiavimo rezultatams. Netiesinės judėjimo lygties skaitiniai sprendiniai gauti integruoti laiko atžvilgiu taikant baigtinių elementų ir skirtumų metodus. Itin daig dėmesio skirta viduriniojo taško įlinkių ir plastinių deformacijų energijai vertinti. Gauti skaičiavimo rezultatai parodė, kokią įtaką sąstandų išdėstymas ir anksčiau išvardyti parametrai turi išskirstytąja sprogimo apkrova veikiamų plokščių elgsenai.

scholarly journals Prognosis on Concentration of Soil Organic Matter Using Maps of Organic Matter Distribution and Progress Mathematical Models

2011 ◽  
Vol 68 (1) ◽  
Author(s):  
Raluca SFARU ◽  
Petru CARDEI ◽  
Vergil MURARU
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Mathematical Models ◽  
Plane Surface ◽  
Organic Matter Content ◽  
Matter Content ◽  
Initial Moment ◽  
Matter Distribution ◽  
Soil Organic Matter Content ◽  
Moment Distribution

This paper presents a method of prognosis of organic matter content evolution in a plane agricultural surface soil, using the information obtained by initial scanning with spectrophotometrical techniques. The scanning result – map of organic matter content distribution – is used as initial moment distribution for calculating the evolution of soil organic matter content in terms of time. In order to calculate the evolution in time of organic matter quantity, mathematical models described by differential equations known in specialty literature are used: Willigen et al. (2008 are used. .Knowing this evolution, we are able to evaluate the optimum moment applying and the fertilizer quantity necessary for obtaining the appropriate parameters of soil nutrients. Therefore, this method aims at predicting the evolution of organic matter content in an agricultural soil, on a plane surface, for being able to add in due time the chemical fertilizers treatments needed.

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