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# Energy Conservation - Science topic

Explore the latest questions and answers in Energy Conservation, and find Energy Conservation experts.

Questions related to Energy Conservation

Dear researchers,

I am currently working on the development of a Low Mach Number multi-species solver (a system similar to that used in LMN combustion, but with no reactions at present ...) I am having issues with deriving the exact temperature equation (note that c_p varies for each species...) I emphasize that I am looking for having an equation expressed as a function of the temperature (not enthalpy, not internal nor total energy !)

- Can you please help by providing some references that can help to derive this equation ?

- Shall I start from the conservation equation of the internal or total energy ? should I neglect specific terms ?

- From your experience, is the inter-species diffusion term important and should be taken into account in such a system of GE ?

- Same for the term div(Pu) ? any ideas

- Same for the viscous tensor (u Tau) ... this is so complex to code in fact ....

Thanks for your comments and recommendations !

Regards

Elie

We have shown that the Lorentz transformation diverges to infinite energy at zero volume approaching a relative velocity of c. In the limit of small velocities the Lorentz transformation gives a three times higher field energy increase than the kinetic energy equation. The Galilean transformation does not transform field energy or volume if the relativistic invariant field transformations are considered. The Euclidean transformation allows a description of kinetic energy as a pure relativistic effect of increasing experienced volume. In the limit of small velocities the Euclidean relativity transforms field energy in the same relation as the kinetic energy equation.

Is the invariance of energy density a necessary rule in physics and the violation of this rule a reason to refute Lorentz transformation?

Energy conservation can be expressed in different ways, such as the temperature equation and the enthalpy equation. However, the two equations do not behave the same way when used in Computational Fluid Dynamics (CFD) simulation (finite difference method and finite volume method). My question is: why? If someone can give me a brief explication.

Circular Economy and Triple Bottom line are two main tools in achieving sustainable development goals. But many academics, professionals and stakeholders are finding difficult to distinguish the difference between them and also fail to interconnect them. In this aspect, how they are inter related in terms of construction industry and technological applications?

I would very much appreciate thoughts about drivers and barriers for development of ESCOs in Africa. Maybe this particular question should be firstly considered on the more limited markets. Eventually assessing of the situation with drivers and barriers should be done on the level of the regions or even on the level of particular countries. Furthermore, maybe it will be promptly bundled with several more questions including one as Whether SuperEsco may assist in overcoming key barriers?

For example ants that developed thermoregulation of their nest. Bees that generate heat through movement and the storing of energy in other forms such as in honey or wasps that just protect their queen long enough to start a fresh in spring. Maybe there is other more exotic and complex or simple examples out there?

Arakawa(1966)'s Jacobian(his eq. 46) is a mean of 3 components: J++(eq.36), J+x(eq.37), and Jx+(eq.38), which have different conservation properties. I am trying to show the difference when using different version of Jacobian in the simulation of two dimensional turbulence, which can be formulated as the stream funciton(\psi)-relative vorticity(\zeta) equation:

\frac{\partial \psi}{\partial \t}=-J(\psi,\zeta)

The model was initialized with \zeta(\psi), such that the relative vorticity is a function of the stream funciton and J(\psi,\zeta)=0, therefore the flow field does not change with time. My result shows that energy/enstrophy remains almost conserved for a while but blows up anyway(for the accumulation of round-off error?), no matter which Jacobian implementation was employed, I am confused.

The Fourier-spectral method was emplyed for spatial differencing( so continuous form of J

^{++}, J^{+x}, and J^{x+}were used in the code) and I know that the conservation property of Arakawa Jacobian, 1/3*( J^{++}+ J^{+x}+ J^{x+}), should be independent of the sptial differencing technique. So I supposed that 1/3*( J^{++}+ J^{+x}+ J^{x+}) should be better than using any of the 3 alone, in terms of energy/enstrophy conservation. However little difference was observed when different initial condition was used. In the simulation, horizontal diffusion in contained in a wavenumber filter to remove the shot waves beyond 2/3 of the maximum wavenumber. Highly possiblely it is an uneducated question, but would be appreciated if someone can explain.Hello Researchers,

Energy is one of the most influential sectors in recent years. So, optimal management of this sector will be of great importance. In your opinion, what will be the energy management issues, in the future?

Dear colleagues,

I need your help. The law of energy conservation in fluid dynamics is associated with Bernoulli equation or, in more general case, with Lagrange-Cauchy equation. I am interesting in the paper were this association was first declared. It is not Bernoulli own thesis, since the law was formulated in the middle of XIX c. I would like to know first arguments and definition of energy of the pressure term in the equation. As far as I know, Rayleigh was first who noted energy of pressure in fluid in his paper "On waves" (1876). But he did not give any definition what is the energy and how it has to be calculated. I am interesting in first definition.

In powder metallurgy, energy is consumed in powder production, ball milling, powder compaction, and sintering. Whereas in casting, the energy is consumed only in melting the ingot. In some of the papers, I have read that energy consumption is lower in powder metallurgy. How? Can anyone explain, please?

Redshift of radiation energy density has been taking place since the early universe due to the expansion of the universe. How much energy has been lost? How does our cosmological model account for it?

Case example: Author A stated an equation 'Dk= 4/3K (8RT/M)' in their report.

Author B cites this equation and writes in her/his report as "... the equation of xyz can be expressed as Dk=48 (RT/M) { ref:Author A}."

which probably have the same meaning but in different form. Any opinions?

Hello everyone,

I'm studding thermal properties of amorphous SiO2(a-SiO2) via molecular dynamics(LAMMPS) using Tersoff potential( ). But I'm experiencing a continuous temperature increasing issue in nve ensemble with a time step of 0.5fs. Problem can be solved by reducing the time step to 0.1fs. But my calculations are kinda time consuming ones so I really need to have the energy conservation with the 0.5fs time step. Anyone who experienced a similar issue with Tersoff potential (for a-SiO2)? Hope someone could give me an advice on my issue.

Stay safe.

Thank you

Chamara Somarathna

Over the years I have repeatedly encountered the problem that NVT dynamics of simple liquids and solids with a Langevin thermostat do not manage to keep the desired temperature. I have observed this behavior for several atomic and molecular liquids with VASP as well as with ASE. Sometimes this can be fixed by reducing the timestep and/or increasing the coupling constant (within reasonable limits), but in some cases, even this does not help.

My current system is pre-equilibrated liquid pentane at T = 300 K at its experimental volume with all masses set to 10 amu and a semi-empirical GFN0-xTB Hamiltonian. I have tried increasing the coupling constant from 0.02 au (suggested value) to 0.05 au and 0.10 au and decreased the time step from 4 fs to 2 fs and 1 fs, but even after 20 ps of simulation time and a pre-equilibration of 10 ps with an even higher coupling constant the average T of the simulation remains at ~290 K instead of the desired 300 K.

I have made similar observations in countless VASP simulations of atomic liquids and solids (DFT Hamiltonian), so I'm starting to think this is a fundamental problem of the LV thermostat? If I'm not completely mistaken that behavior means that the thermostat can not put energy into the simulation fast enough. But where is the energy going? With such a short time step energy conservation should be really good but obviously it isn't.

What is my misconception, what am I doing wrong, and how can I fix that behavior?

Any help would be greatly appreciated.

Jan

The smaller, the better? What can we benefit from using mini/micro channel heat exchangers in refrigeration and air-conditioning systems? Any thoughts shared here will be much appreciated. The following are my bits for your comments.

1. Compact from high heat transfer area-to-volume ratio (e.g., the ratio ~ 1/d for a cylindrical flow channel while d is the channel diameter)

2. Reducing refrigerant charge from small refrigerant-side volume with small OD tubes

3. Maximising capacity/COP with trade-off between decreasing pressure drop and increasing heat transfer coefficient by effective refrigerant flow distributing/circuiting

4. Air-side heat transfer coefficient increase from enhanced air flow disturbance with small OD tubes and narrow spacing tube banks

5. Low air flow pressure drop from using small OD tubes so both fan power and noise may be decreased

The smaller, the better for heat exchanger fluid flow channel size? This is one of the hot topics with users of our Refriglab cloud eTools ( www.refriglab.com being available for free trials). For developers and designers, an interesting question is how we can benefit more from a single mini/micro channel air coil design.

This post is a follow-up to my previous ones at LinkedIn:

The 3D Taylor-Green vortex problem is a well-established adademic test problem for decaying turbulence. For a careful comparison of two discontinuous Galerkin-FEM for the incompressible

case at Re=1600, I refer to N. Fehn et al in arXiv:1905.00142 (or IJNMF 2019). Results for under-resolved TG flow at higher Re numbers can be found in the Ph.D thesis by P.W. Schroeder "Robustness of high-order divergence-free FEM for incompressible CFD", Göttingen 2019, Sec. 9.1.3. For the inviscid TGV at Re=\infty, one observes for the method without any stabilization for

the fully turbulent flow for t \ge 10 a simple redistribution of kinetic energy., see Fig. 9.14. This unphysical behavior is sometimes called "thermalization" or "white noise".

To the best of my knowledge, the currently best numerical simulation of the incompressible 3D Euler TGV can be found in N. Fehn et al. in arXiv:2007.01656. The authors show that the kinetic energy evolution does not (!) tend towards exact energy conservation which implies an energy dissipation anomaly. The proper representation of the Reynolds stress tensor requires an appropriate numerical dissipation. In my opinion, it would be good to share the experience of other colleagues regarding the given problem and a proper choice of numerical dissipation which does not perturb the divergence-free constraint.

When we derive differential equations for flow, i.e. the mass, momentum, and energy conservations, we use Taylor's series to determine the relationship between the 2 points. Are there no other series that produce a more precise equations?

Dear respective researchers, please give your reply.

Thank you very much.

Kind regards.

Energy conservation is the result of several processes, such as productivity increase in terms of technological progress. However, energy efficiency is measure of energy intensity in a specific process.

We know that the energy density of the gravitational field around masses is negative.

This fact is a consequence of the analogy to the electrostatic attraction of different charges. If different charges come closer, the electrostatic field energy becomes converted to kinetic energy. In the electrostatic case this is obvious, because the electric field around both charges becomes weaker.

But in the gravitational case, the situation is just reverted. Approaching masses gain kinetic energy and the surrounding gravitational field becomes stronger. The only possibility, matching to energy conservation, is that the energy density in the gravitational field is negative.

But this fact has consequences. We also know that gravitational waves exist and that they have a positive energy contents. If gravitational waves are pure oscillating gravitational fields, the same fields which surround masses, then their energy content also would be negative. Therefore a gravitational field component, oscillating with normal gravitational fields but with positive energy density must exist.

Further consequences concern the generation of gravitational waves. Large heavy celestial bodies encircling each other generate gravitational waves, which are detectable light years away. The emission of gravitational waves costs kinetic energy. Obviously a mechanism exists, which converts the kinetic energy of moving masses to gravitational waves.

But what happens to the gravitational waves travelling through space? The oscillation amplitude becomes smaller and smaller and the energy density is reduced proportional to the square of the covered distance. What finally remains is a tiny contribution to positive gravitational field energy density.

We then come to the question, is the universe an infinite flat space with giant clouds of galaxy clusters inside or is it a closed S3-sphere. Let us assume it is a closed S3-sphere. In this case all gravitational waves finally would add up to a positive gravitational field energy, surrounding us in the background. In an infinite flat space the gravitational waves irrecoverably would escape together with fast particles and electromagnetic radiation.

What are the consequences of a positive gravitational field density surrounding us? The answer is simple, as long as there are no gradients we would not feel anything. If there are gradients, they cannot be steep, because they would be equalized by a gravitational wave flow, moving with the speed of light. But if there aren’t consequences all the arguments above wouldn’t be relevant.

This leads us to the final considerations. If giant moving masses produce gravitational waves, detectable light years away, tiny moving masses may also produce gravitational waves but with a small amplitude far beyond our detection capabilities. Even quants of electromagnetic radiation then could become a source of gravitational waves. The key point is, that stars contain fast moving particles and a high level of radiation. They therefore must be a considerable source of incoherent non detectable gravitational waves. But this flow actually would lead to a permanent gradient in the density of the positive gravitational field energy in the environment of stars. Dark energy therefore could be the same as the energy density resulting from flows of incoherent gravitational waves out of stars. The influence on galaxy dynamics and the details of the interaction between negative and positive gravitational energy must be investigated.

As my PhD work, I am working on underwater sensor networks and need a suitable simulator for designing in terms of effective routing and energy conservation.Among all available such as NS2, NS3, OPNET, OMNET, QUALNET, which is the best one to work with?

I am trying to make a smart phone charger by converting the wasted heat while cooking our food using thermoelectric generator (TEG).The main issue is I need to add a 5 V DC cooling fan along with a heat sink in one part of TEG in order to make that part cooler than the other one. If the DC fan is powered from the generated electricity using TEG, then will there be enough remaining electrical energy to charge a smart phone?

Some researchers consider rotation variables as work-conjugate with moments, others think that the displacement derivatives is, and others use semi tangential rotation as work-conjugate to conservative moments

Any explanation or more references?

What you say about, the idea of integration of SPV with an electrolzer and PEM fuel cell, how much energy we will lost?

Is it possible to combine together electrolyzer and fuel cell without external energy source?

As electrolyzer is used to produce hydrogen by splitting water into hydrogen and oxygen by using electricity and hydrogen fuel cell uses hydrogen as a fuel to converts chemical potential energy into electrical energy. And it’s common that people use extra waste energy produced by SPV (solar voltaic system) in electrolysis to produce hydrogen and in the absence of sunlight they use this fuel hydrogen to produce electricity by using a fuel cell. And my question is it possible that electrolyzer and fuel cell work together supply each other electricity and hydrogen fuel? If we already lost energy due to heat and always get less energy by fuel cell than we have spent on electrolysis, so maybe these processes are only for energy storage.

Sorry for my bad English as I didn’t explain a very simple question very well.

SPV, Solar voltaic system

PEM, Proton-exchange membrane

phosphoric acid plant energy conservation and quality control

There are different proofs that the quantum nechanics (QM), more exactly the quantum formalism (that was NEVER contradicted by experiment), does not admit a substructure of particles following

**continuous**trajectories. As two rigorous proofs I recommend my articleand section 5, "Does a quantum objecthave a 'particle' ? ", in my article

Deleted research item The research item mentioned here has been deleted

However, with all my efforts until now, I didn't succeed to prove a stronger statement: that the quantum object, which travels in our apparatus(es) does not possess a

**weird 'particle'**which jumps accross disjoints regions, separated by a space in which the wave-function is null. This problem arises very strongly when we have to do with a wave-function consisting in two or more wave-packets traveling through isolated regions, e.g. : |ψ> = |a> + |b>.In my last article mentioned above, I used as assumption the idea that a particle cannot do such a jump. i.e. cannot jump from the wave-packet |a> to the wave-packet |b>. The motivation is that an instant jump between two disjoint regions would mean, in a suitable frame of coordinates in movement with respect to the lab, that the particle disappears for a while from the universe. That would contradict the energy conservation, which has to be respected in any frame of coordinates.

Could there be a NO-GO here? Could it be that it is impossible to prove that there is no such weird particle? Could it be that it though exists?

The Hamiltonian function H is defined as the total energy of a system, the sum of kinetic and potential energy. Lagrangian function L is defined as the potential energy subtracted from the kinetic energy.

Both functions are essential in solving for predicted movement in a many bodied problem of celestial mechanics. The Hamiltonian is conserved, while the change of Lagrangian with time is minimized in each interval.

That energy is conserved is intuitive. Minimizing the change of Lagrangian takes a bit of explanation that is usually not given. It has to do with the way the action S is calculated from L. One explanation is that in the nature of objects in a group moving under their combined gravities and individual momentums, the path of least resistance is the one in which the least possible conversion of energy between kinetic and potential occurs. This is the simplified explanation for the non specialist.

It's a bit of mystery why a physical system in vacuum space time would be biased against conversion of energy between kinetic and potential. The Lagrangian is suggesting the potential and kinetic energies compete with each other for control of curvature.

In an extreme high gravity the space curvature is tending to enclose the source in an event horizon, like a concave curvature. The opposite must be a convex curvature with respect to the source of kinetic energy. This difference may be a physical cause of bias against conversion between potential and kinetic energy. It is inconvenient in the mechanisms of stress energy and is avoided when another path is available.

In the present question it is recognized and well known in publications that a Legendre transformation is able to compute the Hamiltonian from the Lagrangian subtracted from the change of Lagrangian with logarithm of velocity, for a fixed location. Maybe some additional character can be deduced of space time and the objects it processes, especially how velocity and acceleration relate H to L. Conventional GRT has no such bias, but classical Celestial Mechanics does.

Why Can The Hamiltonian Be Computed From The Lagrangian?

I have done a couple of calculations with this dispersion corrections and range separated functionals. The complex under study is Cinnamic---DMSO from XRD studies, where the ethylene group is 3.4 Angstroems from the S of DMSO (dimethylsulfoxide). The LMO-EDA ends up with reasonable energies, except for polarization energy that is way out of range

-------------

ALL BASIS SET HARTREE KCAL/MOL

------------- wP57X-D / TZV

ELECTROSTATIC ENERGY ES= 35.155915 22060.69 kCal/mol ??

EXCHANGE ENERGY EX= 0.001502 0.94

REPULSION ENERGY REP= 0.020100 12.61

POLARIZATION ENERGY POL= -35.152773 -22058.72 kCal/mol ??

DFT DISPERSION ENERGY DISP= -0.008141 -5.11

TOTAL INTERACTION ENERGY HF OR DFT E= 0.016604 10.42

However using MP2 I get reasonable energies.

-------------

ALL BASIS SET HARTREE KCAL/MOL

-------------

ELECTROSTATIC ENERGY ES= -0.006687 -4.20

EXCHANGE ENERGY EX= -0.015563 -9.77

REPULSION ENERGY REP= 0.025771 16.17 kCal/mol

POLARIZATION ENERGY POL= -0.002422 -1.52 kCal/mol

MP2 DISPERSION ENERGY DISP= -0.005410 -3.40

TOTAL INTERACTION ENERGY HF OR DFT E= 0.001099 0.69

TOTAL INTERACTION ENERGY MP2 E= -0.004312 -2.71

Can anyone suggest a reason for that? Does anybody have a reference for H-bonds?

Thanks.

Consider the one-particle wave-function

(1) |ψ> =

*α*|a> +*β*|b>, with |*α*|^{2}+ |*β*|^{2}= 1.where a and b are eigenvalues of some operator, e.g. path- operator.

Then, the amplitudes of probability

*α*and*β*are usually defined as giving, theough their absolute square, the probability of obtaining the result a or b. We get a detection on path a with probability |*α*|^{2}, or on path b with probability |*β*|^{2}.But

*α*and*β*have an additional phenomenological meaning. For instance, in interference experiments, they determine the contrast of the fringe pattern and the position of the pattern.Though, my question goes further: in each trial and trial of the experiment, what do the amplitudes

*α*and*β*? Let the detectors be ion-chambers, and let our particle be electrically charged. The detection is due to the ionization of the gas in the chamber by the charge of the particle*.*But, which effect have*α*and*β*in a given trial of the experiment? These amplitudes are not physical properties of the particle, as charge, energy, linear momentum, etc. Then, how do they influence the material in the detector?No doubt there is an influence, since along the run of the experiment the detection on path a occurs with probability |

*α*|^{2}, and the detection on path b occurs with the probability |*β*|^{2}. Therefore, it's due to these amplitudes, that in a given trial of the experiment a detector fires, or remains silent, and only one detector fires. But, how does it work, how does a detector interact with an amplitude?I want to know the share of coal for producing electricity and steel production

With the Energiewende, the German government pursues a long term energy strategy which aims to transform the energy sector by mid-century. To achieve this it has implemented a comprehensive, long term policy framework which receives broad support across the political spectrum. The United States lacks a similar approach. The reasons are likely manifold. My question is how the character of each country's federalism impacts the long term energy approach of both countries and might help to explain differences?

i am taking an ieee 14 bus system.i consider an outage and i apply demand response on mostly loaded bus.taking 8,4,10 hrs as valley,peak,off peak periods respectively i want the price variations with respect to demand.

Recent research has delved into many aspects of aviation fuel consumption. In some ways the analogy with a personal automobile is apt: you fill up, and you drive until the tank is nearly empty, repeat. The difference for aviation is that the weight of the fuel itself significantly adds to the power needed to fly ("it takes fuel to fly fuel"). So, although the equations and ideas are well known, I would appreciate pointers to industry standard methods. Our goal is analytical shortcuts that would allow this idea to be built into a model of a major airlines network.

If you want to reduce your energy bill, it is quite possible to insulate the roof and walls. However windows are a more difficult subject, and they let out significant amounts of heat. Are there any solutions that can reduce this loss?

**I am working on a project titled as energy conservation of exhaust gases of SG-34 (18-V) gas engine at thermal power station**

The future of oil is in ambiguity. Developed countries seem to be replacing oil with other renewable energies. Please leave a comment? Thankful

Hi, I was trying to bring a transient conduction system problem to the frequency domain in order to facilitate the solution and I began to wonder: Can the analogy between electrical circuits and thermal circuits be extended to transmission lines for transient heat conduction? Let me explain my reasoning:

If one rearranges the terms of the Fourier conduction equation, in 1D cartesian coordinates:

q=-k*A*dT/dx

q/A * 1/k = -dT/dx

Now making q/A=q" (heat flux) and 1/k=R' (thermal resistance per unit length), one can write it as:

q"*R'=-dT/dx (1)

Writing out energy conservation, and considering the source term equal zero:

d/dx(k*dT/dx)=rho*cp*dT/dt

Identifying that k*dT/dx=-q" (the heat flux in an element), we can rewrite it as:

-dq"/dx=rho*cp*dT/dt

Now, calling C'=rho*cp (Thermal capacitance per unit length), the energy conservation can be rewritten:

-dq"/dx=C' * dT/dt (2)

Equations (1) and (2) are of the same form as the Telegrapher's equations for a 1D transmission line, which for the general case are:

-dV/dx=L' * dI/dt + R' * I (3)

-dI/dx=C' * dV/dt + G' * V (4)

Where I and V are the current and voltage, L' is the inductance per unit length, R' is the resistance per unit length, C' is the capacitance per unit length and G' is the shunt resistance per unit length.

**The interesting part here is,**if one makes L'=0 (no thermal inductance) and G'=0 (no thermal shunts in a flat plate), eq. (1) matches eq. (3) (V~T, q"~I) and eq. (2) matches eq. (4).

The consequence is that all features of a transmission line apply (given L'=G'=0) to thermal conduction: Wave propagation, wave distortion, etc. It also becomes relatively easy to associate different materials by using two-port networks and other basic electrical engineering concepts.

What do you think? Is that possible? If not, why? I'm really curious!

Hi,

I am struggeing with a numeric implementation of the free field 2D Green function of the wave equation in space and time domain, which, according to all references I could find, is proportional to

( t

^{2}-(r/c)^{2})^{-1/2}and thus, has a singularity at r/c=t. If I want to implement this function as numeric array that can be convolved numerically with a source distribution to get a wave field, I do not know how to deal with this singularity.

An option would be polynominal extrapolation, but I would prefer a mathematically correct attempt.

I thought I might have to analytically convolve the Green function it with a sinc function first, to attain a function that can be accutely sampled according to the Nyquist criterion, but this still did not resolve the singularity.

In consequence, I am also wondering if the 2D Green function is even integrable. I believe it should be in terms of energy conservation, but I ended up with an infinite integral.

Thanks for your time!

The current density made by electrons with number density n inside a conductor is J=qnv. How the energy conservation equation is expressed? and what type of energies these electrons have? I am working on a formalism that connect the quantum and classical nature of electrons moving inside a conductor. In such a case the energy conservation representing the particle from the two points of view should hold.

Consider 3 hollow conductor spheres A, B and C together with the charged hollow conductor sphere X of charge Q.

Let the spheres A, B, C and X be of a similar capacitance C. i.e.The difference in their capacitances is so small to be significant.

Bring the spheres A, B and C towards X so that the enclose it.

Momentarily earth the spheres A, B, C and X so that A, B and C each gain a net charge Q. Let the volumes of the spheres A, B, C and X each be V. i.e. The difference in their volumes is so small to be significant.

The charge density Z on X was,

Z = Q/V

The charge densities Z on A, B and C are,

Z = Q/V+Q/V+Q/V

Z = 3Q/V

The results show that the charge density of A, B and C charge system is higher than that which was on X. This is possible because the electrostatic field on the outer most sphere is the vector sum of the electrostatic fields emanating from the charged inner spheres. So the charge density on the outermost sphere is more than that which was on the central sphere if we add the net and induced charges on the surface of the outermost sphere.

Therefore a higher charge density is being created at a certain point in space without as expending energy.

This is compared to crunching a group of like charges together without expending

energy.

**This goes against the law of energy conservation.**

For more information visit

I am confused about how to apply Conservation of Energy and Conservation of Momentum to the following situation:

**A horizontal spring-block oscillator moving on a friction-less surface is in motion when a block of equal mass is gently lowered onto the oscillating block and moves together with the lower block.**

How does the addition of the second block impact the Kinetic Energy, the Potential Energy, Period and Amplitude of the the spring-block system?

If I apply conservation of momentum to the addition of the second block, then the combined two block system will have reduction in velocity. And since KE is 1/2 mv squared, the reduction in velocity will have a greater impact on reducing KE than the doubling of the mass. In fact, the overall KE will reduce by 50% if velocity halved while mass doubled.

**So here is my question**, if KE of this spring-block system was reduced by 50%, does that mean that this situation violated Conservation of Energy? If it does not violate it, then what accounts for the 50% reduction in KE? What did that energy transform into?

Thanks very much.

In Loop quantum gravity, particles couple on spin foams and not on gravitons (gravitational force exchange boson). And the spin foam changes as it is evolving through space and time. Does it imply by Noether's Theorem that energy is not conserved in this theory due to non-homogeneous spinfoam?

Moreover, some research suggested that Lorentz invariance is broken. And Lorentz group is subgroup of Poincare group.

Another question:

Implies no translation invariance no Lorentz invariance or no Lorentz invariance implies no translation invariance?

I am solving the natural convection heat transfer problem within an enclosure with few heat generating components using Fluent.Around this enclosure,I have considered the fluid domain. To consider the solar effect, i have used the solar model ( No radiation model).Will this problem converge? Energy will be conserved? . I have a thought the since this solar load is applied as heat source (heat flux) on the outer surface of the enclosure, It is pumping the heat to the inside fluid. Because of this fact, inside fluid temperature may keep going and resulting in no convergence. Will that be true.

Please share your views.

When we try to find out algorithm to calculate evolution of mechanical system in discrete time, we find, that energy is not conserving. Does this mean some deep law? Is it possible to use momentum or only use coordinates difference / delta t?

Noether's theorem is the following: To every continuous symmetry one obtains a conserved quantity.

Example: If a physical theory is homogenous in time (i.e. the physical laws are valid independent on time), energy is conserved.

Question: Are there physical theories, where energy is not conserved? I know that in General Relativity energy is covariantly conserved and in quantum mechanics, energy has uncertainties. But are there any well-known physical theories, where no energy conservation/ homogenity in time exists?

Maybe quantum gravity theories?

I created this thought experiment but it seems to contradict energy conservation.

Electric charges may have the tendency to mirror energy without transforming it.

Let’s charge a conductor sphere until it gains a positive charge. Let’s enclose it in neutral concentric conductor spheres as shown in the attached image.

The spheres are insulated from each other, are good electric conductors and are close to each other.

Firstly connect the positively charged outer surface of A to the Earth. Then connect the negatively charged inner surface of A to positively charged outer surface of B. Then connect the negatively charged inner surface of B to the positively charged outer surface of C. Then lastly connect the inner negatively charged surface of C to the positively charged sphere at the center. If my sphere at the center held electric potential energy of 10J how much electric energy will I get from all the different electric current movements. I think that with enough spheres I will get more electric energy than the 10J I used in the charging of the inner sphere.

Your thoughts are welcome.

Ideal air loads (heating and cooling) much higher than other HVAC system loads!

As the name suggests, Ideal air loads, this suppose to estimate a small load when compared with HVAC systems. However, when I compare Ideal air loads with any other HVAC system the ideal load is always higher. Does any one knows why?

The figure below shows a comparison of different systems for my building.

I want to work on localisation and energy conservation aspects. So far I have come across NS2, NS3 or OMNet++.

When googling for this topic, I don't get helpful results. In one article I have seen u=Re(psi* H psi). However,

i), in stationary cases, the kinetic energy density, psi* T psi, becomes negative in domains, in which E<V ('tunneling');

ii) it leads to energy conservation even in cases,

where the classical potential energy depends on time: V=V(r,t), because it obeys an equation of continuity without source term.

The following formula does not exhibit these two deficiencies:

u = hbar^2/2m |grad psi|^2 + V|psi|^2

Here,

@u/@t * div j = @V/@t |psi|^2

What do you think?

Thank you!

Hot water heating system for residential use is a norm. The portion of electricity bill for water (and space) heating can be around 30% in some countries. Is there any information of this for Gulf countries (Saudi Arabia and surrounding countries) or reference to areas with arid climate?

what should be the considerable variables to find out heat exchanger working at stenter machine ? if heat exchanger engineered with tubes & Air to Air exchange method?

Assume a single-particle wave-packet landing on a beam-splitter. Two wave-packets emerge, one transmitted, |a> and one reflected |b>.

In "which-way" experiments we place a detector on the path of each one of the wave-packets |a> and |b>, i.e. D

_{a}and D_{b}. In each trial of the experiment either D_{a}will report a detection, or D_{b}, but not both. Consider a trial in which D_{a}reports a detection; one may be tempted to think that the wave-packet |b> is a*fiction*, does not exist really.But this is not true, as it can be shown if we deflect the two wave-packets so as to cross one another, and get interference.

*Interference can't be obtained between a wave-packet, say |a>, and a fiction*. Therefore, we have to admit that both wave-packets contain some form of matter.Let's recall that if the detector is a photographic plate, during the detection process the wave-packet delivers

**energy**that impresses the plate.Now, if the wave-packets |a> and |b> are identical, both should contain energy. But the collapse enforces that only one of the wave-packets delivers energy to the detector.

What happens with the energy contained in the other wave-packet? Where it goes?

Please pass a logo, a word or a sentence that can change our world.

I was searching for a system/architecture that includes a smart meter as well as several smart plugs distributed in the home. In particular interesting would be how such a system integrates smart appliances into the HEMS

I am currently doing research work on Knowledge Based Building Energy Conservation in which I am using various operational strategies and internal loads to minimize energy consumption. My study is based in composite climate of India and I need BEE recommenced EPI for the same to make relevant comparisons.

We've recently started a small (internal) project on Smart Specialisation and energy. In that respect I'm interested in getting connected to others working on that topic. Tips about relevant literature (reports, articles etc.) are also highly appreciated.

The increasing efforts for insulation of housings often are combined with reduced windows areas to avoid overheating by the sun. This trend does not take in account that the energy of the sun is for free ....especially in the winter time.

Typically decentralized energy generation capacities are connected to the power grid with central dispatch. So "decentralized" means "distributed" or "close to the customer". But traditional power stations are in many cases also located rather close to the customers, for example within cities or at the city borders.

Does "decentralized" mean "small" as compared to "large"? Or does it mean "autonomous" which then means the so called "prosumer" concept: electricity self-generation. This concept actually has much dynamic in countries where political levies and electricity tax rates on electricity are significant and self-generation is exempted from these levies. As a result, electricity sales and revenues from grid operation decline. Thus, the issue is relevant for energy policy which has a simple instrument in hand to stop decentralization: charge levies and electricity tax on self-generated electricity.

Buildings often initiated with the plans of reducing energy during its construction and operation period fail to achieve the energy targets.

I am currently doing a literature review on this topic.

It is an encouraging trend that building energy modeling has been more used at various phases of the building life cycle to improve energy efficiency and reduce energy use. However, is the detailed energy simulation always the best choice? Maybe not. Especially when there is very limited information about the building, or there are lots of measured data available for the building. In these cases other methods or tools might be better choices.

Dear all,

I'm working on cloud workload prediction, focusing on energy conservation. Is anyone aware of high-quality review papers on cloud workload prediction?

Thanks,

Salam

New technologies, such as smart meters, provide access to more detailed energy use information for specific appliances (lighting, refrigeration, TV, radio, smartphone, cellular mobile phone charger, computer, etc) which could support energy use decisions and machine learning in control automation intelligence (ie AC or DC smartgrid microgrid - energy or electricity time of use time series databases for ANN neural network or linear optimization).

Any appliance disaggregated time-series data sets available for machine learning of PV, isolated power or grid connected power systems ?

Usually yellowness appears in solar EVA sheets, after testing in DHT, but when I tried with PID EVAs, it turned into pink colour.

How I can calculate the total energy consumption in a building?

I have all energy bills (Natural gas, Water and Electricity in cubic meter, cubic meter and kW per hour, respectively) in last year for a case study. I want to have the total energy consumption. But, there are different unit for each. Should I convert them to a specific criteria?

I am researching on using data analytics for addressing the issue of unintentional islanding in distribution grids given that renewable energy based generators will increase their penetration. I plan to use predictive grid analytics for which I will require data on events of islanding in any real distribution grid. Basically all the instances when unintentional islanding took place or whenever disconnection from the main grid took place are important.

The basic idea is to pinpoint the instances when events (disturbances) took place which are expected to be recorded, in form of alarms , at least. Events like switching surges, transients , overloads and opening of grid Circuit breakers/ CBs at any feeder node, are important.

The main motive is to analyze what were the conditions just before the actual event happening and so power flow conditions and dynamic data preceding the event are more important. A pre-event classifier will then identify the signatures that can truly lead to islanding, preventing false-tripping of the connected solar PV generator. I have tried contacting Delhi utilities but chances are thin. Can any other resource/source/link be provided?

Most of the MENA region countries are blessed with abundant reserves of oil and gas. Due to this the energy cost per KWh is low in these countries so as the energy bill. However, due to low energy cost there is no energy conservation culture in these regions due to which the electricity producing companies are in great stress during the peak hours as the energy demand is very high. This might result is grid malfunctions, however, due to absence of energy conservation culture the consumers are not playing their role to mitigate the difference between supply and demand. Under these circumstances, what methods could be adopted to encourage the consumers to reduce the energy usage during peak load hours..

The role of energy in the development of humankind is very important.The use of alternative sources of energy will reduce cost in the long run. According to energy experts, the renewable power sector needs to explore alternate avenues of funding through the bond market route. More innovation needs to be done in the area of low cost renewable equipments manufacturing. Conserving energy is the need of the hour.

Various conveyors are available for different processes...which one will be the most efficient??

For example, let's say we set the initial energy input (temperature) at some given value, say 1000 K for the first job. When this job is complete, we take the final positions and velocities and use them as the starting point for the next simulation.

However, rather than set the temperature at 1000 K again (thus adding more energy into the system), we set it at 0 K, and allow the particles to further equilibrate.

My colleague suggests that, because energy is conserved in NVE, the results will be the same as running the simulation in one go. However, I suspect that the particles will tend toward the 0 K equilibration state, after some time.

Any insight would be appreciated!

I am trying to understand rotating wave approximation in terms of quantum optics used in Rabi Oscillations. What is the physical meaning of this approximation? And more importantly why do we need it? Energy conservation?

Waste management, Energy conservation, Water conservation