FINITE TIME BLOW UP OF THE SOLUTIONS TO BOUSSINESQ EQUATION WITH LINEAR RESTORING FORCE AND ARBITRARY POSITIVE ENERGY

Finite time blow up of the solutions to Boussinesq equation with linear restoring force and combined power nonlinearities is studied. Sufficient conditions on the initial data for nonexistence of global solutions are derived. The results are valid for initial data with arbitrary high positive energy. The proofs are based on the concave method and new sign preserving functionals.

Warp Drive with Positive Energy

Space and time traveling is one of the humanity’s most fascinating and challenging topics. The speed limitation makes space traveling highly difficult. Therefore, discovering the warp drive mechanism intrigued humanity to travel in space and time. Miguel Alcubierre proposed a model for warp drive. However, the energy density driven from the Alcubierre warp drive model turns to be negative everywhere. Erik Lentz proposed a shifting vector field in which we shall show that shifting vector field with appropriate spaceship geometry may provide positive energy density for warp drive. Further, we suggest looking at the spaceship geometry as a mother wavelet function with shifting, scaling, and rotation operations that may provide additional positive energy density. This sort of design requires a flexible fuselage that can be stretched and rotated.

THEORETICAL AND NUMERICAL STUDY OF THE BLOW UP IN A NONLINEAR VISCOELASTIC PROBLEM WITH VARIABLE-EXPONENT AND ARBITRARY POSITIVE ENERGY

In this paper,we consider the following nonlinear viscoelastic wave equation with variable exponents:utt-△u+∫_(0)^(t)g(t-τ)△u(x,τ)dτ+μut=|u|^(p(x)-2)-u,whereμis a nonnegative constant and the exponent of nonlinearity p(·)and g are given functions.Under arbitrary positive initial energy and specific conditions on the relaxation function g,we prove a finite-time blow-up result.We also give some numerical applications to illustrate our theoretical results.

The positive energy conjecture for a class of AHM metrics on R^(2)×T^(n-2)

We prove the positive energy conjecture for a class of asymptotically Horowitz-Myers(AHM)metrics on R^(2)×T^(n-2).This generalizes the previous results of Barzegar et al.(2020)as well as Liang and Zhang(2020).

Community microgrid:an approach towards positive energy community in an urban area of Dhaka,Bangladesh

The pollution and toxic greenhouse gases produced by fossil fuel combustion are troubling as global energy demand continues to rise.To mitigate the consequences of global warming,a transition to sustainable energy sources is necessary.This manuscript presents a feasible community microgrid design in Hazaribagh,Dhaka based on meteorological data that leads to photovoltaic installation on the rooftop of a local community building.This study shows a microgrid design of a system with the lowest cost of energy and a large renewable fraction,which is analysed using the HOMER Pro software.Using real-time data,analysis of the system cost,cost of energy,renewable fraction,unmet load,energy purchased and energy sold is discussed.A suitable case for electrification is also identified and presented for the selected community.The proposed case yields a cost of energy of$0.0357/kWh,which is 52%less than the current tariff rate,with a 70%renewable fraction.This study will provide people in this community with more green energy at a lower cost;in addition,this designed microgrid sells additional energy to the grid to avoid possible power outages.The potential for a positive energy community is also investigated in terms of energy consumption and renewable output of the planned microgrid.

Positive energy theorem for(4+1)-dimensional asymptotically anti-de Sitter spacetimes

We define the total energy-momenta for(4+1)-dimensional asymptotically anti-de Sitter spacetimes,which comes from the boundary terms at infinity in the integral form of the Weitzenbck formula.Then we prove the positive energy theorem for such spacetimes,following Witten’s original argumentsfor the positive energy theorem in asymptotically flat spacetimes.

BLOW-UP OF THE SOLUTION FOR A CLASS OF POROUS MEDIUM EQUATION WITH POSITIVE INITIAL ENERGY

This paper deals with a class of porous medium equation ut=△u^m＋f（u）with homogeneous Dirichlet boundary conditions. The blow-up criteria is established by using the method of energy under the suitable condition on the function f（u）.

Strategic Position and Roadmap of China's Renewable Energy

Fast-growing economy imposing higher requirement for energy industry During the "Tenth Five-Year Plan" period,China's GDP grew at an average annual rate of 9.5%,and correspondingly the total volume of energy consumption grew at an average annual rate of 10.5%.

Dark Matter Creation and Anti-Gravity Acceleration of the Expanding Universe

Dark matter is identified as negative relative energy between quarks in proton and is generated in cold hydrogen gas with pressure gradient in gravitational field. Positive relative energy PRE can be generated between quarks in protons in cold hydrogen gas in outskirts of the universe. The mechanisms for such creation of dark matter and PRE are reviewed and updated in greater detail and clearer manner. The so-generated dark matter in a galaxy can account for the galaxy’s rotation curve. Star formation in this galaxy uses up the hydrogen atoms and thereby reduces its dark matter content. Dark matter created in intergalactic hydrogen gas can form filaments. In a hypothetical model of the universe, a hydrogen atom with a small amount of negative relative energy or dark matter at the outskirts of this universe can via collisions with other atoms turn into one with a small positive relative energy PRE. Once such a sign change takes place, gravitational attraction switches to anti-gravity repulsion unopposed by any pressure gradient. This leads to a “run away” hydrogen atom moving away from the mass center of the universe and provides a basic mechanism for the accelerating expansion of the universe. This theoretical expansion and the measured redshift data are both compatible with the conception of an acceleratingly expanding universe and complement each other. But they cannot verify each other directly because the present model has been constructed for purposes different from those of the measurements. But it can be shown that both approaches do support each other qualitatively under certain circumstances for small velocities. Dark matter and PRE in the present model are not foreign objects like WIMPs and dark energy-cosmological constant but can only be created in cold hydrogen gas in gravitational field. To achieve this, infrequent collisions among the hydrogen atoms must take place. Dark matter was created first and can eventually later evolve into PRE in the outskirts of the universe and in the intergalactic void. Dark matter and PRE will disappear if the hydrogen atom carrying them becomes ionized as in stars.

Exponential Growth of Solutions for Nonlinear Coupled Viscoelastic Wave Equations with Degenerate Nonlocal Damping and Source Terms

This paper is concerned with a system of nonlinear viscoelastic wave equations with degenerate nonlocal damping and memory terms.We will prove that the energy associated to the system is unbounded.In fact,it will be proved that the energy will grow up as an exponential function as time goes to infinity,provided that the initial data are positive initial energy.

Global Classical Solution and Asymptotic Behavior to a Kind of Linearly Degenerate Quasilinear Hyperbolic System

This paper is concerned with the global classical solution and the asymptotic behavior to a kind of linearly degenerate quasilinear hyperbolic system in several space variables.When the semilinear terms contain at least two waves with different propagation speeds,we can prove that the system considered admits a global classical solution by the weighted energy estimate under the small and suitable decay assumptions on the initial data.Furthermore,we can show that the solution converges to a solution of the linearized system based on the decay property of the nonlinearties.

Open Positions for Senior Scientists and Engineers in School of Energy Research at Xiamen University

The School of Energy Research at Xiamen University (SER-XMU) was founded in 2007, to consolidate and expand research in the areas of Physical Energy, Chemical Energy, Bioenergy, Energy Efficiency and Energy Econom-

Open Positions for Senior Scientists and Engineers in School of Energy Research at Xiamen University

The School of Energy Research at Xiamen University (SER-XMU) was founded in 2007, to consolidate and ex-pand research in the areas of Physical Energy, Chemical Energy, Bio-energy, Energy Efficiency and Energy Econom-ics. SER-XMU is seeking senior scientists and experienced engineers to serve as Thrust Leaders and Principal Inves-

Open Positions for Senior Scientists and Engineers in School of Energy Research at Xiamen University

The School of Energy Research at Xiamen University (SER-XMU) was founded in 2007,to consolidate and expand

Open Positions for Senior Scientists and Engineers in School of Energy Research at Xiamen University

The School of Energy Research at Xiamen University (SER-XMU) was founded in 2007, to consolidate and expand research in the areas of Physical Energy, Chemical Energy, Bio-energy, Energy Efficiency and Energy Economics. SER-XMU is seeking senior scientists and experi-enced engineers to serve as Thrust Leaders and Principal Investigators.

Open Positions for Senior Scientists and Engineers in School of Energy Research at Xiamen University

The School of Energy Research at Xiamen University (SER-XMU) was founded in 2007,to consolidate and

Open Positions for Senior Scientists and Engineers in School of Energy Research at Xiamen University

The School of Energy Research at Xiamen University(SER-XMU)was founded in 2007,to consolidate and expand research in the areas of Physical Energy,Chemical Energy,Bio-energy,Energy Efficiency and Energy Economics.

Open Positions for Senior Scientists and Engineers in School of Energy Research at Xiamen University

The School of Energy Research at Xiamen University (SER-XMU) was founded in 2007,to consolidate and expand research in the areas of Physical Energy,Chemical Energy,Bio-energy,Energy Efficiency and Energy Economics.

Open Positions for Senior Scientists and Engineers in School of Energy Research at Xiamen University

The School of Energy Research at Xiamen University (SER-XMU) was founded in 2007, to consolidate and expand research in the areas of Physical Energy, Chemical Energy, Bio-energy, Energy Efficiency and Energy Economics. SER-XMU is seeking senior scientists and experienced engineers to serve as Thrust Leaders and Principal Investiga-

Open Positions for Senior Scientists and Engineers in School of Energy Research at Xiamen University

The School of Energy Research at Xiamen University (SER-XMU) was founded in 2007, to consolidate and expand research in the areas of Physical Energy, Chemical Energy,