Reverse Definition and 311 Threads

Hi, I'm trying to reverse a list in Common Lisp without using the reverse function. I've had a go but it's not working. Can anyone help? (defun my-reverse(my-list) (cond ((null my-list) nil) (t (append (my-reverse(cdr my-list)) (list (car my-list)))))) Thanks.

Based on the very basic understanding on enzymes I have gained from Year 12 Biology and Chemistry, I don't undesrtand why the enzymes specific shape also helps the reverse reaction. I guess my trouble would be due to the simplified diagrams I've seen from Biology, where only the forward reaction...

Certainly fission is a prime example of entropy. But what about fusion? Doesn't fusion look like a process that goes from a disordered state to an ordered one? Out of chaos comes order!

Hi, I'm trying to write a simple program for reversing a string stored in memory. This is what I've come up with. For some reason this code coredumps, so something is wrong. any ideas ? #include <stdio.h> #include <string.h> #include <stdlib.h> char *reverse(char *buf,unsigned...

How far can you go? I only got up to 7 digits http://cognitivefun.net/test/10

From what I know, to get the reverse trace form of the Einstein field equations, you must multiply both sides by gab (I didn't have a lot of time to make this thread so I did not spend time finding the Greek letters in the latex). This turns: Rab- \frac{1}{2}gabR= kTab (where k=...

What is the order of the reverse saturation current before breakdown in a zener diode ?

First time writing , hope all goes well. Looking to understand the properties of rare Earth magnets, are you able to reverse the polarity of two magnets that are stuck together and separate them with an electromagnetic pulse or any other instrument ? Please if this is the wrong forum ...

If I have the following transfer function: x = A1 + A2*y + A3*sin(A4*y + A5) + A6*sin(A7*y + A8) +A9*sin(A10*y + A11) +A12*sin(A13*y + A14) I know x and all the A coefficients, how would one solve for y?

I'm getting a rough idea of the holographic principle relating the shannon entropy of a boundary surface to the thermodynamic entropy contained within the bounded volume. So far as I understand the primary claim is that the total information needed to describe the entirety of the internal...

Hi all I was hoping someone could help answer the following question:- I think of two numbers A & B The HCF of A & B is 8 The LCM of A& B is 192 What are the numbers A&B? I do the following:- A*B = HCF & LCM A*B = 8 * 192 A*B = 1536. Prime factor (PF) both numbers to...

This has to do with optics and a bit about biology. plus lenses (reading glasses) help the help the eyes focus on things that are close while while minus lens do the opposite. What is your opinion about using reading glasses (wearing them while reading and doing other near work) to reverse or...

why does diode breakdown into conduction when reverse biased?

I need to find a function f(x) such that \int_{-\infty}^{100+10n} (f(x)) dx = 1-0.1^n for n=1,2,3,4,5,6...∞. How would I go about this? It must be exponential in some way I'm guessing? This is not a homework problem. I don't just want the answer. I want guidance on this type of problem...

Hi, Given 3D points P1(200,60,140), P2(300,120,110), P3(3,0,-1), P4(-100,0,-1) and the radius of arc C1MP3 is equal to radius of arc C2MP1. How do I calculate coordinates x, y, z of points C1 and C2? Points C1 and C2 are centers of two reverse arcs which are tangent to each other at point...

Hi, Given 3D points P1(200,60,140), P2(300,120,110), P3(3,0,-1), P4(-100,0,-1) and the radius of arc C1MP3 is equal to radius of arc C2MP1. How do I calculate coordinates x, y, z of points C1 and C2? See this image. Points C1 and C2 are centers of two reverse arcs which are tangent to...

Hello This is a concept I have been researching for a while. A company called LIM Technology has made a few working prototypes of this very concept they call a simple cycle engine; they have a patent for the intake valve technology. Here is their website...

"Reverse Microwave" There's some buzz going around about this product, http://www.businessinsider.com/this-reverse-microwave-chills-beer-in-45-seconds-2013-10 which claims to be able to cool drinks rapidly. Honestly, I'm a bit unimpressed. It looks like it's just a refrigerator that...

A string is wrapped around a reel. The reel is the set on a horizontal flat surface. This string is set perpendicularly to a surface and pulled. The reel starts to roll in the direction away from the string. However, as the angle between the reel string and the surface decreases, the velocity of...

So I look at the Minowski diagrams, and I can understand that moving on the y means moving in time, and moving on the x means moving in space, but drawing some diagrams of my own, I find it impossible to see why it would imply FTL travel. All objects travel either directly on the x...

Homework Statement Why integral from a to b of f(x) equals "minus (-)" integral from b to a of f(x)? when a<b or a>b Homework Equations The Attempt at a Solution

A four minute video from NASA http://www.space.com/22264-sun-s-magnetic-field-will-soon-flip-stormy-space-weather-ahead-video.html Let's hope the climate scientists start talking with the solar scientists.

Homework Statement . A 50 mL acetate solution is titrated with a 0.2342 M HCl solution. The equivalence point occurs at 28.52 mL. Acetate is the conjugate base of acetic acid, for which Ka = 1.8 × 10-5 . b) Write down the titration reaction. c) Find the pH of the acetate solution at the...

So in a supernova explosion for example (5th slide) http://www.astro.princeton.edu/~burrows/classes/541/blastwavesChisari.pdf Ambient medium is accelerated, compressed and heated. It pushes back into the ejecta, creating a reverse shock. Why does it do this and not just emit a drag...

I don't know much about the subject, besides some diagrams and youtube vids, so please bear with me. I'm trying to make a reverse heat pump to cool a small room. If I had a heat reservoir (in a box within the same room) that could increase the temperature/pressure of a refrigerant and then...

Homework Statement I\!f~ f(x+1)=\sqrt{x^2-2x}~~~and~~~g(x)=f(\!\sqrt{x}) Find: g'(x-1) Homework Equations In order to find g'(x-1) I know the following steps have to be taken: f(x+1) \rightarrow f(x) \rightarrow f(\sqrt{x}) = g(x) \rightarrow g'(x) \rightarrow g'(x-1) The Attempt at a...

My problem: There is an LED and a switch. When the switch is closed, I want the LED OFF. When the switch is open, I want the LED ON. What is the simplest circuit I can build to make this happen? The power source can be either AC or DC, whatever is easiest. Thanks!

EE is not my forte. Although this little circuit is so simple that I could get myself 90 percent there, it performs such an important function that I would like to get it more like 99 percent correct. I want to add the circuit to this board...

Okay. First off. This isn't homework. I have been working on a personal project and if I could get an equation for this it would really help me out. I'll try and explain the problem the best I can. What I need: An equation/method where I can specify an angle theta and a 3D line and it...

"Antimatter gravity could explain Universe's expansion:" http://phys.org/news/2011-04-antimatter-gr...-expansion.html "Anti-matter atoms to address anti-gravity question:" http://www.bbc.co.uk/news/science-environment-16756457 Image Source (before editing)...

I want to know the possibility for reducing pressure of reject Brine fluid below the inlet pressure of raw feeding water to RO by a pressure exchanger / Energy recovery turbine in Reverse osmosis system. If its possible, how it works? Please help me in this regards. Thank you

Homework Statement I have a problem where I know P1, P2, V1, and molecular mass. I do not know total mass, final volume, temperature 1 or temperature 2, or the work. I also know that P = 40V^2 + 20 Can I reverse the W = ∫PdV equation into the form W = ∫V dP? Because I could just solve...

Has any experiments been done equal to this scenerio where the twin leaving Earth and seeing Earth time dilated.. but when the twin reverses and returns to earth, the Earth speeds up or go in fast motion? If time dilation is slowing down.. what is the term for time speeding up? Also what...

Dear All, I need you kind support in a problem, which I am unable to figure out. It is regarding thick lens. I am determining lens principal planes and radius using shaping factor and focal length. The forward problem I am using is, Focal length 1/f = (n-1)*[1/r1 - 1/r2...

Hi all!, first post! I'm programming an attitude estimation and control algorithm for a satellite. So I need a reference "trayectory" for my control system to try to follow. The generation of that attitude profile is tricky: point to the sun, if sat has access to a certain city, point to...

I would like to understand exactly what happens when a PN doped crystalline silicon cell is shaded.Lets assume we have ten solar cells wired together in a series string.That there is plenty of sunlight on the first nine cells but cell ten is completely shaded.Lets say the forward bias of each...

From the tensor, ##\bar{h}^{ij}=h^{ij}-1/2\eta^{ij}h## Where, h=##h^i_i##, Prove that ##\bar{h}=-h##, Where, ##\bar{h}=\bar{h}^i_i##

So I was learning about the LC circuit and I know that an inductor would oppose the change in current through it, so if I connect a charged capacitor with an inductor, the charges on the capacitor would want to flow to the other side and neutralize the two plates like it does when the two plates...

I've written a modified mutation algorithm that I am trying to derive a more analytical probability model for. The basic algorithm works like this: 1. The probability of mutation is P(M) = 0.01. 2. If mutation occurs, then: a. The probability that mutation-type A is P(A|M) = 0.50 b. The...

Hi, I need to know how to calculate the power level and pulse width required to revers the polarity of a rod or bar shaped alnico magnet, depending on the width. I also don't know whether to use AC or DC power. I'm prototyping an invention and it needs to be as power efficient as possible.

Hello All, I'm designing a circuit board that needs to run on a 12VDC supply and will need to supply a fair amount of power to drive a bunch of 12V relay coils, in addition to some electronics. Since I want to keep the voltage drop on the supply a small as possible, I thought about using a...

Dear All I have been recently started to work with Reverse Engineering technology and I would now like to determine a circuit layout diagram of a charge controller from its PCB Layout. Can anyone please help me with this one. I have uploaded the PCB design for your reference. Please...

Hi, I wonder how you calculate the "inverse COP" of a heat exchanger. Say a heat exchanger has a COP 4 at 0 degrees C. Under that condition the heat exchanger consumes 1kW, and deliver 4kW heat. So if you now turn it off, and instead heat one side and cool the other side with external heat...

I would like to know if it's possible to build a dynamo that instead of having an electrical current driven through a coil by movement of a magnet to generate electricity could be driven by ac to move the magnet or coil in a vertical motion instead. If so, (which logically it sounds possible to...

We know we can biject the segments of size 0.5, 0.25, 0.125, … to the segments of size 0.25, 0.125, 0.0625, …, furthermore we can biject these segments to the segments of size 0.125, 0.0625, 0.03125, …, and there is no end to it. So, we can use index #1 for segment 0.5. We can as well use index...

I have a stepper motor with built-in controller/servo system that requires a supply voltage of 24 VDC +/- 10%. The problem is, the power system I'm using is a lead-acid battery that is normally maintained at a top up voltage of 27 V to 28 V, which exceeds the upper limit motor input. Most of the...

Hi guys I am not sure if this is the right forum, so please feel free to move this topic around to where it belongs. This is not homework help, but something I have been wondering about lately. Anyway. I am wondering about som differences between VAr Import and reverse power for...

I've been thinking about this on and off for awhile now. It first started with the idea of a solar trap. Solar trap being something like having a solar collector focusing light on a container of water, having an infra red barrier around the container, and a black body at the centre. Incoming...

Conduction in reverse biasing too?? Is it the case with transistor?? I have a mechanical analogy of diode in which a socket is provided with a one way valve. (figure 1st below). The arrow inside the circle shows the direction of motor pump. When there is enough pressure to lift the valve...

Homework Statement Integrate (x+2y) over y=1+x^2 , y=2x^2 and x=0, x=1 (dy dx) Homework Equations Graph is sketched. The Attempt at a Solution y = 2x^2 --> x=(y/2)^(1/2) y = 1+x^2 --> x=(y-1)^(1/2) integrate over y=0 to y=2 problem encountered when solving definite integral from y=0 to...