Large Distance Modification of Newtonian Potential and Structure Formation in Universe

In this paper, we study the effects of super-light brane world perturbative modes on structure formation in our universe. As these modes modify the large distance behavior of Newtonian potential, they effect the clustering of a system of galaxies. So, we explicitly calculate the clustering of galaxies interacting through such a modified Newtonian potential. We use a suitable approximation for analyzing this system of galaxies, and discuss the validity of such approximations. We observe that such corrections also modify the virial theorem for such a system of galaxies.Comment: 13 pages, 3 captioned figure

Ant Colony Optimization Algorithm to Dynamic Energy Management in Cloud Data Center

With the wide deployment of cloud computing data centers, the problems of power consumption have become increasingly prominent. The dynamic energy management problem in pursuit of energy-efficiency in cloud data centers is investigated. Specifically, a dynamic energy management system model for cloud data centers is built, and this system is composed of DVS Management Module, Load Balancing Module, and Task Scheduling Module. According to Task Scheduling Module, the scheduling process is analyzed by Stochastic Petri Net, and a task-oriented resource allocation method (LET-ACO) is proposed, which optimizes the running time of the system and the energy consumption by scheduling tasks. Simulation studies confirm the effectiveness of the proposed system model. And the simulation results also show that, compared to ACO, Min-Min, and RR scheduling strategy, the proposed LET-ACO method can save up to 28%, 31%, and 40% energy consumption while meeting performance constraints

Adaptability evaluation of pavement structure to replacement treatment subgrade of black cotton soil

Aiming at the typical engineering problem of black cotton soil (BCS) subgrade under the alternation of dry and wet climate in the region of Nairobi, Kenya, this paper takes the pavement structure as the research object, and the numerical calculation model of BCS subgrade is established based on the consolidation coupling theory of unsaturated soil. Taking the modulus and thickness of the subbase as variables, the deformation characteristics and additional stresses of different pavement structures are analysed. Then the adaptability of different pavement structures to replacement treatment subgrade of BCS is evaluated by gray incidence decision analysis method. The results show that whatever the pavement structure is, neither subgrade modulus nor thickness is sensitive to the pavement surface deformation, and the deformation differences between each pavement structure are more obvious in wet season; the additional stress at control layer bottom and pavement surface decreases with the increase of subbase modulus, whereas the stress may increase at subbase bottom; the additional stress at subbase bottom, control layer bottom and pavement surface all decreases with the increase of subbase thickness for pavement Structure I and II. For pavement Structure III, the change of subbase thickness is not sensitive to the additional stress at the control layer bottom and pavement surface, whereas the stress at subbase bottom increases with the increase of subbase thickness. It is concluded that the most adaptable structure is pavement Structure I, which can minimize the comprehensive level of pavement settlement and additional stress

Effects of active galactic nucleus feedback on cold gas depletion and quenching of central galaxies

We investigate the influence of active galactic nucleus (AGN) feedback on the galaxy cold gas content and its connection to galaxy quenching in three hydrodynamical simulations of Illustris, IllustrisTNG, and SIMBA. By comparing to the observed atomic and molecular neutral hydrogen measurements for central galaxies, we find that Illustris overpredicts the cold gas masses in star-forming galaxies and significantly underpredicts them for quenched galaxies. IllustrisTNG performs better in this comparison than Illustris, but quenched galaxies retain too much cold gas compared with observations. SIMBA shows good agreement with observations, by depleting the global cold gas reservoir for quenched galaxies. We find that the discrepancies in IllustrisTNG are caused by its weak kinetic AGN feedback that only redistributes the cold gas from the inner disks to the outer regions and reduces the inner cold gas densities. It agrees with observations much better when only the cold gas within the stellar disk is considered to infer the star formation rates. From dependences of the cold gas reservoir on the black hole mass and Eddington ratio, we find that the cumulative energy release during the black hole growth is the dominant reason for the cold gas depletion and thus the galaxy quenching. We further measure the central stellar surface density within 1 kpc (Σ1) for the high-resolution run of IllustrisTNG and find a tight correlation between Σ1 and black hole mass. It suggests that the observed decreasing trend of cold gas mass with Σ1 is also a reflection of the black hole growt