Building Definition and 919 Threads

In obtaining the materials to build a transistor, should one choose wafers of the same Miller indexes? Will the lattice structure affect the interaction between two wafers?

I was imagining how one could design a newer, more efficient city then the cities we have right now and I came up with a fairly basic design concept that I later Googled and found I was not the first. That concept was that of a snowflake. But why design a new city? Currently modern cities are...

I'm not really sure where this thread belongs... Do you know any (free) program that can allow to build bands (instead of just line curves) to take into consideration the errors of a graph? eg if I want to draw: y= bx + (c \pm \delta c) to get something like the yellow band in this (of course...

Hi, I'm new here. Nice to meet you all. I would like to ask anyone here knows how to build a controller. Any source where i can find the schematic diagram. Any help would be appreciated.

Greg Egan just proved something nice: the E10 lattice, famous in string theory and supergravity, can be described as the lattice of self-adjoint matrices with integral octonions as entries! I'm not sure this result is new, but I've been wanting it for quite a while and haven't seen it...

Homework Statement A large weight hangs over the side of a building from a cable. The cable goes over a pulley to a horizontal roof and is attached to a small weight of half the mass. The coefficient of sliding friction between roof and the small weight is 0.5. What is the approximate...

Is there any reason why logic gates are built using transistors instead of PN junctions? Wouldn't it be more cost-efficient to use PN junctions? I am referring to CMOS logic gates. Also, what can a transistor do that a PN junction can't?

Homework Statement A rocket is being launched along the line y=x from the base of a building, and another rocket is being launched from the top of the building parallel to the bottom rocket. Another rocket is being launched directly upwards away from the building. Find: The height of the...

Homework Statement A parity bit will be 0 if the data contains an even number of 1’s and it will be 1 if the data contains an odd number of 1’s. If during transmission a 1 is changed to a 0 or vice versa, then the parity check at the receiver will fail. Determine the parity P for 4–bits of...

Hi All, I know I may be shooting in the dark here but...I was hoping that someone on this forum can assist me. I am trying to build a tray dryer/ medium scale dehydrator. I'm starting a small fruit drying business but cannot afford to buy an commercial dryer. I've heard that some entrepreneurs...

Homework Statement A brick is thrown upward from the top of a building at an angle of 23.8 degrees above the horizontal and with an initial speed of a 14.2 m/s. Acceleration of gravity is 9.8 m/s/s. If the brick is in flight for 3.3 s how tall is the building? Homework Equations...

I want to have a powerful magnetic levitation device as an attraction for college fest and also as my first big project! So I need to know how to start with it. I need to workout with all theory parts before I start building it ! Where to start from?

I'm building a wall mounted cabinet, with a fold down door. It is for my grandson's slot car track, in his bedroom. The door is 3x7 feet and weighs approximately 40 lbs. It is mounted length wise, on the wall. I think I need tension or torsion gas springs, which pull instead of push. I don't...

Hello. I'm looking to build a strong electro magnet with ac power. I was going to use a MOT transformer so the primary was going to be the same windings. For the secondary windings though I'm trying to decide if I want to go with a higher current or voltage. I would assume that a stronger...

If I want make 8 bit processor I think I need following think 1) ALU 2)control unit 1)ALU responsible for Arithmetic and logic Unit 2)control unit include with multiplexer and decoder circu main component for processor ALU 8 bit decoder multiplexer Q1 I have option for decoder decoder...

I need a contraption that can keep a ball spinning, smoothly, at a slow speed. If it has a variable speed control, that would be better, but minimally it would need to spin a soccer ball and take around 30 seconds to make a full rotation. The look of the device doesn't matter, just that it...

I thought it is easy when I was watching all sorts of instruction videos. However, now I have Fisher and Paykel stator and rotor, and I cannot solve how rotor is suppose to spin. The magnets are so strong that I do not think any wind will be able to move it. When I received my parts, I had hard...

Hi there I am new to this site but I have been reading on it for a while. I have a question, I am building a loading ramp for my box truck to load my lawn mower in. it will be about 12 feet long and 6 feet wide I was wandering what size steel box tubing would be best used for this the...

Hey guys, I'm having trouble with this problem set I'm working on at the moment. I'd appreciate some help with this question: (I'm only asking about number two. Ignore number one please.) So if the length for the hypotenuse of the leftmost triangle is represented by: c^2 = x^2 + y^2 Then...

Hi, I'm interested in building a gas powered DC generator to charge a small 36 volt battery bank. I think a 500w 36volt generator would do fine, but my question is, what would be a minimum displacement necessary to turn the generator? Basically, the smallest, most efficient, gas engine to charge...

On a 100' - 0" (100 feet 0 inches) long building, how many screws are required to screw gutter to the building 12" (12 inches) off center (O/C)? Could anyone tell me how this problem would be worked. And sorry there is not image to go by for this, as it is just a word problem. Thanks.

So as a side project for my professor, I'm supposed to 1) build a recirculating simple pipe bend 2) experiment and get data 3) do hand calculations via fluids equations (Bernoulli) 4) simulate with solidworks 5) compare results Restrictions: budget and availability of finding products...

Hello so I just want to make sure I Am doing this correctly. also I know there is a magnetic field force formula. That is F= qv (dot) B How would I go about using that formula with the magnetic field I created from the solenoid in the picture? Thanks for any help! Zig

Homework Statement A single roomed building measureing 12.0m x 12.0m x 2.5m is maintained throughout the day at a temperature of between 18-23°C. Each wall is to be constructed from 2 layers of common brick, an internal particle board and a layer of insulation. The building is heated using...

Hello, does anyone know how much is the minimum required points that should be connected from the following units to the BMS: 1) chiller 2) AHU 3) FCU 4) Fan 5) Pressurizing fan 6) VAV with reheat coil 7) VAV without reheat 8) Pumps (secondary chilled water circuit)

Im still not 100% sure on engineering, last year i was set on civil engineering but took a year off and changed my mind too mechanical as it was more broad. I have accepted this program from seneca college in Toronto and was wondering what other engineers/professionals think of the program...

I have completed a few chapters. I am writing a story about a couple on New Earth which is this planet that is not 4.5 billion years old but still habitable by all Earth species. Right now in my story they have made some cow's milk cheeses and butter and they have a child but they want some...

I am a property manager and I have a building that is 1 story, with about 20ft of space from the drop ceiling to the roof. I have two exterior doors that when opened, cause a major draft of air blowing in from the outside. This causes comfort issues in the summer and winter and then also causes...

Homework Statement Need to design a system where the lamp (output) turns on when sound is heard and turns off after 10 seconds of no sound, but it must also be dark (light sensor).Homework Equations The Attempt at a Solution I have put a Light Sensor (that is set to let current flow when it is...

Hi Physics Forums, I'm a biochemist whose electronics experience is limited to resonant RLC circuits. I have been tasked with building a device that essentially acts as an RF antenna. In transmit mode, this device must create a sine wave of specific frequency (current plan is 40.05 MHz)...

Homework Statement It's a verbal problem. It goes like this: "Peter needs to buy some screws: large, medium, and small. He goes to the hardware store and orders 100 screws for a total of $100. For each large screw he was charged $5.00, $1.00 for each medium one, and $0.05 for each small one...

Hi guys, I'm an incoming engineering student at Ohio State and am really fascinated with what goes on under the hood of my car. I've done about 20 minutes of fruitless light searching on how engines work and wanted to know if there are any classic textbooks or resources on this topic. Also, I'd...

Hey guys! Not sure if this is the correct place to post this, but this seemed the most relevant... So I'm working on a coilgun to shoot 45mm steel spheres, but I need to figure out how long [diameter, gauge, etc] my coil needs to be. I want to generate a force of about 5 Joules or more...

Hi, I'm currently in the process of making my own shampoo dispenser for my shower because when using shampoo there is problems getting all the shampoo out of the bottle. I'm going to make it dispense the shampoo using a sensor. There will be different settings for the length of someones...

Homework Statement A 2.0kg physics book is dropped from the roof of a skyscraper 240.1 m high. While the book is falling to the ground, a horizontal wind exerts a constant force of 11 N on it. Ignore air resistance. a. How far from the building is the book when it hits the ground? b. How...

I would like some introductory level references for building an n-body gravity simulation. I work for the supercomputer challenge [ http://challenge.nm.org/ ] and I build the teaching models each year we use to train teachers in computer modeling and provide as an example model for the students...

Homework Statement Basically construct the circuit on a breadboard and take some measurements: http://ithaki.eng.auth.gr/aetos/elab/image.php?x=44 Homework Equations - The Attempt at a Solution - My only question is how am I supposed to do the GND grounding that it wants? o.O

So my PI suddenly decided she wants me to learn electronics. And so she started me off building a balanced detector. So here I am with this circuit I know nothing about, knowing nothing about electronics... Anyways, quick question on reading Op-Amps. In my circuit diagram, there are two...

Hello! Could you, please, name some(if any exists) good reviews about building the general relativity? In all details: with attempts of building the vector theory of gravitation by Poincare; with long Einstein's efforts of building the scalar version; with prediction some of the effects, like...

I am considering getting a BS in Aerospace engineering one day. I want to get a PhD at some point as well. What are the opportunities for people interested in building spacecraft ? Are there many job openings for NASA or commercial space agencies like SpaceX for building space-related...

Hi , I am building a Quadcopter ,i am not sure how to decide(or calculate) the length of the 4 arms .I know that it depends on the propeller size ,i am not sure if any other parameters are involved ,is there any formula to find the length using the parameter(s)?

I'm trying to build up some intuition with Gauss's law, calculating the flux through surfaces given certain charge configurations etc. For example, for any number of different charges enclosed in a box or sphere, if I move far away can I consider the object as a point source having the sum of...

Hello, I have recently been given an experiment, where i will need to build a boat. The requirements are ° the boat must have dimensions smaller than 8in x 8 in ° have a mass minimum of 25.0 grams °the weights when loaded into...

Homework Statement A stone is thrown from the top of a building with an initial velocity of 20 m/s downward. The top of the building is 60 m above the ground. How much time elapses between the instant of release and the instant of impact with the ground? Vi = -20 m/s height = 60 m t = ...

Homework Statement Hi there, I have just installed AVRstudio version 5 to be able to write programs so that we can use the micro controller ATmega 8. The encountered problem is that after the code has been build, the compiler complains on lines which doesn't even exists! How is this...

Hi all, For an applied electronics class I'm currently taking, we have to come up with and build an electronics project of our choosing from scratch. I think it would be cool to build some sort of radar device. I have been looking into phased array radars, radar speed detectors, etc., but a lot...

Homework Statement A ball is launched at an angle of 38° at 16m/s off of the top of a building, the ball finally hits the ground after 45seconds. What is the height of the building? Gravity is normal 9.80m.s squared. The answer to the problem is 9480m. Homework Equations I just needed...

Hey guys, I built up this design for a hand-powered crank generator with four neodymium magnets, but am having trouble getting a reading through a voltmeter. I want to try and amplify the voltage as well but that will come later. Here is our setup http://imgur.com/a/0aM4W#0 I am not...

Hi, I'm two years away from graduating with a bachelors and I am planning to apply to grad school. I know that research experience is important, but I haven't had any opportunities play out until now. I got offered a research assistant position, but the research is not on science. It is...

I'm confident that most of us have seen the advancements in quantum levitation recently, and this has aroused questions among the geek community ( us : ) ) Anyway, if I were to, hypothetically, want to build one... How do I- *cough*- one do such a thing. What equipment and supplies are in play...