Reduction Definition and 472 Threads

Hawking and Hertog's new paper "A Smooth Exit from Eternal Inflation?" does away with the infinite multiverse of Hawking's previous theory and proposes a cosmology that predicts "a simpler and finite universe". But I can't figure out the extent of this reduction to a "simpler and finite"...

$\textsf{a. Find the determinants by row reduction in echelon form.}$ $$\left| \begin{array}{rrr} 1&5&-6\\ -1&-4&4 \\ -2&-7 & 9 \end{array} \right|$$ ok i multiplied $r_1$ by 1 and added it to $r_2$ to get $$\left| \begin{array}{rrr} 1&5&-6\\ 0&1&-2 \\ -2&-7 & 9 \end{array} \right|$$...

So I've been learning how batteries work. What I learned is that a battery consists of 2 pieces of metal both with different electronegativities. These metals react with an electrolyte. One metal (called the anode) is oxidized and has its electrons removed, leaving behind a positive ion which...

< Mentor Note -- thread moved to HH from the technical physics forums, so no HH Template is shown > in the solution sheet, He took the 18 ohms parallel with the 9 ohms and not the 6 ohms. I don't understand why he took this approach. I was going to take 18 ohms parallel with the 6 ohms and find...

Quick note: Sorry for dominating the homework help board, guys! But, I wanted to say thank you to everyone who replies to my excessive questions. This forum's input has become integral to me as I am in a position now where I can't go to my teacher for help because of the logistics of commuting...

If the number of wheels on a vehicle are reduced from four to three or two (assuming problem of balance is taken care of), will it reduce the amount of energy spent on all resistance (such as friction/slippage at tyres, rolling resistance etc) faced by vehicle at the wheels. It is also assumed...

I'm doing a little experiment on reducing iron oxide back to bare iron. I'm going to use a blued rod, coconut oil and ultraviolet light. Im using coconut oil because information from this site suggests that it is very transparent to uv light. https://www.hindawi.com/journals/jspec/2013/540417/...

My background is QM as done in Griffiths( So yes I have a background of operators, observables and scattering matrix), Classical fields as done in Goldstein and Particle physics as in Griffiths. Griffiths actually works out Feynman rules for QED and QCD. I've started QFT with Peskin and...

Something that routinely comes up as a problem at work is when we size flow projects for piping systems. We calculate pressure drop across a length of fixed diameter for compressible gasses, but we do not calculate pressure changes through an expansion or contraction with gas (for example...

I am trying to work out which is oxidised and reduced in this reaction2mg + o2 ->2mgo so the mg has a oxidation number of 2+ and the oxygen has a oxidation number of 3+. I am not sure what the oxidation numbers of magnesium and oxygen are in magnesium oxide as it does not work out and it is not...

I was wondering if anyone knows how to set up a procedure in REDUZE that will decompose tensor integrals appearing in QCD loop calculations into a sum of scalar topologies with the tensor structure factored out? I've had a look at the appropriate manual but I am not entirely sure how to...

Hi, I'm trying to figure out the equivalent change of the Centre of Gravity when an amount of liquid is reduced. This could be a fuel oil tank on a ship. In other words, if I e.g. reduce the content what would be the equivalent vertical change of Centre of Gravity on a ship with a total...

Interesting new jet plane has rolled out of its hanger. https://img.purch.com/h/1400/aHR0cDovL3d3dy5zcGFjZS5jb20vaW1hZ2VzL2kvMDAwLzA2Ni80NjMvb3JpZ2luYWwvZHJvbmUxX3dlYnNpdGUuanBnPzE0OTYyNjgyNTY= It looks like there are vibration modes of the plane that during normal operation would shake the...

What is the difference between valence factor and n-factor for oxidants and reductants? Take ##H_2O_2## as an example. What is the difference between the n-factor and valence factor for this compound? Also, how do I find the n-factor for any oxidant or reductant?

Homework Statement Let In = ∫x(cos^n(x)) with limits between x=π/2, x=0 for n≥0 i) Show that nIn=(n-1)In-2 -n^-1 for n≥2 ii) Find the exact value of I3 Homework Equations ∫u'v = uv-∫uv' is what I use for these questions The Attempt at a Solution Rewritten as ∫ xcos^n-1(x) cosx u'=cosx...

Homework Statement A question asked to write an equation for the reduction of PbCl2 The answer key was PbCl2+X ----> Pb+XCl2 where X can be: ...Fe, Mg...but not Na or K Why are Na or K not acceptable?

I try to solve a block diagram reduction example but when I did the operations, sign of one operation is incorrect. I tried to understand why it is so? Would somebody like to help me. (1) First I carry the feedback into the parallel line. (2) I add +1/G1H1 in the parallel line because I...

Looking for effective weight lost or horsepower gained... Original wheels weighed 29 lbs front wheels 20" x 10" rear wheels 20" x 11"New wheels weigh 22 lbs front wheels 19" x 10" rear wheels 19" x 11"for the purposes of the exercise I will assume tire weights are the same since the side wall...

I would like to ask why cannot I think G5 in series with G3(G4+G6G7) and then after muliplying them why I cannot think of G5*G3(G4+G6G7) in parallel to G2 so sum G2 and G5*G3(G4+G6G7) ? Thank you.

Homework Statement : [/B] Qstn no. 3.10 in the attached image. [ Moderator note: Copy of relevant portion of attachment inserted to make it visible here] Homework Equations : For power calculation, [/B] Power = torque * angular velocity... Also, reduction gear is used to deliver lower outout...

Lab manual is confusing me, and I'm not sure if its actually wrong, or the wording is bad, or if this is because I'm not understanding something. It says: "Before a broth can be tested for nitrate reductase activity it must be examined for evidence of denitrification. This is simply a visual...

Good afternoon, i have been trying to find without success the standard reduction potential for the next semireaction: 2CO2 +2e- <-> (C2O4)^2- Could someone please help me with that or tell me where could i find this potencial?. Thanks

< Mentor Note -- thread moved to HH from the technical forums, so no HH Template is shown > Hi! I've been working on reducing a controller with block reduction in order to understand it and I have trouble to continue since I've stumbled across something that I haven't seen before. My goal is...

< Mentor Note -- thread moved to HH from the technical forums, so no HH Template is shown > Hi! I am trying to reduce a PID controller by using block reduction rules but I am having some trouble Here is the block: https://postimg.org/image/9am5n8bsp/ My attempt: 1. Multiply (1/I)*(1/s) ->...

I am calculating the amount of torque required to give mobility to a 7000 lbs oilfield service vehicle. The vehicle has a rectangular frame with fairly even weight distribution. The radius, from wheel center to edge of tire is 11.5 inches. These tires are treaded with various half-inch tall...

Homework Statement Reduction from top network to bottom network in the screen shot. I can not find the steps that have been taken to do this. Fault impedance = Zfa = Zfb = Zfc = j0.5 Homework EquationsThe Attempt at a Solution in hand written screenshot, sorry for the mess, just to show it...

Derive a reduction formula for the integral: $\int \sec^nx dx, \;\;\; n \ge 2.$ - without any help from an online integrator.

Homework Statement Homework EquationsThe Attempt at a Solution Should I find the characteristic equation then find the solution y2? Or just integrate the expression of part (a)?? Part B, just find the derivatives and plug into the ode

Homework Statement teacher gave me the correct solution which said that the result from him was as follows ##\frac{1}{a^2b^6}## Homework Equations original problem was as follows ##\frac{ (\frac{1}{a})^2*b^{-3}}{ ab^3 }## The Attempt at a Solution...

I want put here an imaginary, but close to reality scenario. We have 3 MW power plant here having 1800 kg/hr or 0.5 kg/sec steam flow and the exhaust will be steam at 1 bara pressure and 100C temperature. If a cooling system of 2000 ton capacity is fitted to the Condenser, how much it can...

Homework Statement Show that the determinant of is (a-b)(b-c)(c-a) Homework Equations Row reduction, determinants The Attempt at a Solution Apparently I got a (a-b)^2 instead of (a-b) when I multiplied them up. It would be grateful if someone can point me out where the mistakes are.

If Have have the torque needed to turn the input shaft of a 500:1 Gearbox with no load, can that information allow me to calculate the opposite. I want to know the torque required to turn the output shaft. What I mean is, if you were to apply the force to the output shaft. In other words, use...

Spin current is defined as ##I_s=I_\uparrow -I_\downarrow## in which ##I_\uparrow## and ##I_\downarrow##are the currents of spin up and down electrons respectively. One of the advantages of the spin current is that if ##I_\uparrow =-I_\downarrow##, then the charge current ##I_C=I_\uparrow...

Hi, could anyone explain to me how odd harmonics in the power system are reduced or removed? I've read that in transformers the harmonics produced by the load circulate if the secondary side is wired as delta configuration, yet star is usually used on secondary side i believe? I've looked...

In tube end forming practices, is it possible to first reduce the diameter of the pipe (tube 0.9mm thick) and then expand it, at the same end, by about 1mm in total, with a transistion radius of 8mm ? Please see attached image. Though it might be exaggerated, but the image should suffice. I want...

Homework Statement [/B] The reduction formula for tannx is a confusing matter for me, First how do you derive it? Let's use tan3 as an example Here in an integral calculator when it gets to tan4(x) it uses the reduction formula BUT When I ask it to integrate Tan3(x) the answer...

Hey! :o A trucking company has two same trucks. The luggage space is a cuboid with floor area $2m\times 5m$ and height $3m$. The packages that the comany has to deliver are also cuboid. The packages must be distributed into the two trucks. The problem is defined as followed: $n$ packages...

Contrary to potential appearance, this is not homework. I've been out of college for a long time now. Just working on a project with my kids and I'm trying to approach specific energy of these reduction reactions from the theoretical side, mostly so I know what sort of safety precautions to...

Homework Statement integral of cot^2 x / csc^8 x dx Homework Equations u = cot x du = csc^2 x du The Attempt at a Solution if I use reduction formula I could answer this but it's going to be very very LONG SOLUTION I just need some basic integral work.

Since the field in the title is opposing the original magnetic flux that causes the induction, how can it be reduced? I understand that a laminated magnetic core can be used. 1) Where is this magnetic laminated core placed? 2) Can it be obtained from specialized manufacturers? 3) My choice for...

Hi Guys, I am looking for a high level overview concerning resistor noise and how to reduce it. I have read the following general statements. Carbon comp resistors are rated at 0 db. I read this somewhere. Vishay metal film resistors MIL-R-10506 are rated at -40 db...

So I know that things in the Universe tend to move toward a state of least potential energy. This is why forces point in the direction of decreasing potential energy, as everything is trying to minimize its potential energy. So my main question is: does Gibb's free energy basically just...

Homework Statement part c Homework Equations The Attempt at a Solution Jm+2=m+2-1/m+2 Jm=m+1/m+2 Jm hence Jm+2<Jm should i expend Jm+2 Jm+1 Jm to the term J0 then compare them? why the inequality is <= but not <? should i use M.I to proof it??[/B]

Hello, I have a silicon wafer with a 50nm layer of copper sputtered on it. I coated it with a 1µm of positive photo resist and patterned it with a UV laser stepper. Then I developed it and washed it thoroughly. The pattern has a surface area which measures appx 1300µm x 8µm. What I want to do...

http://highered.mheducation.com/olcweb/cgi/pluginpop.cgi?it=jpg::::::/sites/dl/free/0023654666/650262/Standard_Reduction_Potential_19_01.jpg::Standard reduction potentials The voltage is slightly different in my textbook. The questions I am trying to answer involve getting both half reactions...

I need some math help. I am very good with my hands and building mechanical things, but not-so-good with math calculations. ( I got a D in high school physics but can fix damned near anything...) I would appreciate some help figuring this out. I have attached a diagram showing what I am trying...

Hello, i am a junior mechanical engineering student and i was given the task of designing (on paper) a gearbox. I chose to design a worm gear single speed reduction gearbox. I know the basics of what composes it which are the worm, worm gear, input and output shaft bearings and the housing the...

When attempting to find an answer to the "quality" of sound one attains from various audio cables, most of the research leads to the very subjective answers of audio/sound engineers. I was hoping to gain some insight from a physics/engineering perspective. I'm curious if an expensive or...

Homework Statement You are given some undirected graph G = (V, E), along with a set S which consists of 0 or more pairs of G's edges. As an example, a complete graph on 3 vertices (a triangle, basically) would be described as follows: G = (V, E) = ({v1, v2, v3}, {v1v2, v2v3, v1v3}). A set S...

Homework Statement I am not yet at the chapter of equations of equilibrium, plus it says the couple moment is not 0, so I assume it just about the loadings and not including the reactive forces and reactive moment. Homework Equations F= 1/2*b*h M= 1/2*b*h*d The Attempt at a Solution So if I...