Engineering

I came up with this idea almost forty years ago after a science class lesson teaching about sound frquency interaction with different materials. My adoptive mother had been diagnosed with brain cancer and was under going radiation therapy which was having some pretty horrible side effects upon her. I immediately thought about the idea of using two seperate sound waves tuned to those specific cells to destroy the tissue rather than using radiation which has such a harmfull effect upon surrounding tissue. As a fifth grader there was only so far I could go with that thought experiment, but the idea of frequency and sound was strong on my mind. . Not long after that we l…

I was just wondering if anyone knows why submarines normally have lower surfaced speed compared to speed when submerged? It's understandable for diesel-electric submarines, where diesel engine is there more to charge batteries than to provide propulsion and as a result surfaced speed is lower, but what about nuclear subs? They have exactly the same propulsion in both cases, but for example, US Ohio-class SSBN has a top speed 12 knots surfaced and 20 knots submerged. Same story with Russian/Soviet Akula-class 10 knots vs 28-35 knots. Is it due to lower performance of the propeller when it's close to the surface or is it something else?

Hello all. Can anyone explain what are the long and short greenish lines for in this compass, or how to use them ? Many sites on the net without clear explanation. They can be rotated with the bezel, it is not about the black fixed line aligned to the sight not shown in the picture. ----> http://www.galaxyarmynavy.com/prodimages/400-big.jpg

Hello science forum! I am a blossoming engineer. My goals are as follows: Get a bachelors in Mechanical Engineering, Use connections i have in the aerospace business to get myself a year internship, Work at various locations to get a vast understanding of the economics & aerospace business in general, Use the money to go back packing across the world to look for people i need of various professions to hire when i start a company, go back home to start a company off of the people i have that will invest in me, expand and attempt to one day join the commercial space industries that will start in my life time. Currently i`m at step one. I recently finished Canadi…

I am planning to build a robotic arm for a particular event in division C science Olympiad, but I am relatively unfamiliar with practical electronics (I know all the math, just not the hardware of it). The robot arm needs to pick up particular objects using a control that you make yourself. For the robot, I was planning to use 4 servo motors (rotation, grabbing, wrist, and elbow). However, I was considering a master-slave interaction to control the robotic arm, as I noticed that the top teams generally succeeded with this concept. Also, in my 'research', I noticed that for the master-slave concept, people used potentiometers for the control wired to an arduino microproces…

So I am currently struggling with resistors blowing out on a PCB. They are 1/4 Watt 1206 resistors, The resistors where designed for steady state, but there is a power spike when the device is turned on (Power spike shown below), also, the power spike is shared by two resistors. What wattage resistor do I need to handle this type of spike. The spike will occur worst case average every couple minutes but generally only every couple hours. Draft2.bmp I am currently testing with 10W resistors, which don't even get mildly hot with these spikes so I know these would be overkill.

Hello, everyone! Does anybody know what kind of sawmill waste is used in building, especially in creating of insulation materials? I know that tree bark is used, but I can't find an information about researches and experiments in this theme. Any help here would be appreciated!)

How do I get from sheet metal to annealed welding around a turbine? I have just a little money & got nothing around the house.

This has puzzled me for a while - why haven't space refueling and orbital fuel depots become widespread? It seems like a no-brainer, especially for long missions and putting satellites on GSO. Also for deep space manned exploration it should be much easier to send fuel and the craft separately using a couple smaller rockets rather than a proposed monstrosity of SLS (in a sense that it's huge and super-duper expensive).

Hello everyone, I didn't do much research on the topic, but i guess in many industrial facilities where any fault may lead to dramatic consequences, engineers just use a fault detection unit to prevent any hazardous incident. But I've been wondering if there has been some works on fault prediction, like a technique able to foresee the incident given the actual state of the facility's equipment and the constraints they undergo. This would be very important for the safety of the equipment and the staff. What are your view points on the subject ?

Guys does anyone know about octals and hexals?

I'm really stuck on this question: A fuel gas consists of methane and ethane in unknown proportions is burned in a furnace with air. Combustion is known to be complete and an analysis of the flue gas on a dry basis gives 85.99% N2 and 10.88% CO2. Determine a) composition of the fuel gas, b) the percentage excess air used. My basis I've chosen(Don't know if this is an appropriate basis) is 1 kmol of the fuel gas. I've let x=kmol CH4 and 1-x=kmol C2H6. From there I wrote equations for CO2 formed and theoretical O2 needed, but now I am extremely stuck. Can someone give me a method of approaching these sorts of questions? I don't even know if what I have done a…

What physical effect or device is capable to generate strong radio interference on relatively short distance (around 2-3 m) and in wide spectrum (30MHz-10 GHz or wider)? Could some near-field effects work? Similar to those which work in transformers?

Good whatever time of day it is where you are! Is it possible to create hummingbird-like (3 to 5 grams) or canary-like (12 to 29 grams) flying autonomous surveillance drone with camera and microphone which: can fly to the designated area of interest and spy for decades, e.g. 50 years (by periodically flying to unpopulated safe area in order to go to hibernation mode to recharge quantum battery by means of betavoltaic cell and then upload captured footage to satellite, then resume surveillance activity and so on). Possible technologies of autonomous batteries and accumulators that I’ve found are these: http://www.betavoltaic.co.uk/trickle_charge.html http://techon.…

Hi We are trying to do this experiment for the school Science fair. http://www.sciencebuddies.org/science-f ... #procedure We got all the products (except batteries and audio cable) from Science buddies .We used regular headphones as the phone cable.We used the radio (530kHz-1700kHz) as the reciever.There is no output. Should we change the phone cable? As per the procedure (Use your wire strippers to cut the 3.5 mm audio cable in half. It has three wires inside: left and right audio (with red and white insulation), and ground (uninsulated). Strip about 5 mm of insulation off the ends of the left and right audio wires.) What else could be the problem? We tried putting…

So, we already have fridges with a tap of some buttons and you'll be delivered your weekly shopping, but we could take it further, right? I'm no expert in this stuff, to be honest I have no idea how it would work and what sort of technology you'd need/if it has been invented. BUT I have an idea. Automatic Food: Imagine you run out of food, but you can't go shopping (for whatever reason) What do you do? Order it online? Of course, that's the obvious choice but what if it's important? What if you can't wait for it to be delivered? So; the idea is - Tap a button and the food just turns up in your cupboards/fridge - I.E; teleportation from the store. M…

Hi, I am thinking of making a RC submarine based around the Arduino Uno or Leonardo, and I probably won't use a controller, most likely just either a joystick or 4-5 pushbuttons. Ontop of that I want to be able to send video footage back to me, whether it be on a laptop or just a LCD Display, or via a RCA cable. I think I found a good 100meter tether cable that only has 2 wires? Here is the cable: http://store.openrov.com/collections/2-8-replacement-parts/products/extra-100m-tether Is there anyway I can send so much data with only 2 wires? Thanks alot for the help! This is the camera: https://www.adafruit.com/products/397?gclid=Cj0KEQiAno60BRDt89rAh7qt-4w…

I daydream a lot and love playing video games. Black Ops 3 was recently released and revolved around bionics, attaching machinery to the human body to enhance the human condition and peak. I know there've been works on bionics like a guy with bionic legs presented it during a TED talk, but when do y'all think it will become a trend?

I recently had an idea for a toy line of fighting robots for kids, kind of like these robots from Japan. https://www.youtube.com/watch?v=ufOz00oYzZM There are a few problems I've thought of, so I figured there would be people here, with enough engineering knowledge, to tell me how it would work. How much would it cost to make fully functioning robots like we see in the robots? I was hoping each robot would cost within the realm of $30-40 USD. What about projectile weapons? What would the projectiles be made out of, what size would they be, and how fast would they travel? What would be the sturdiest metal(s) to make these robots out of? Would something …

I had a small refrigerator that used an electric heating element to expand the freon, without the use of a pump or any other moving part and it worked quite well, it even made ice. With all the excess heat of a car engine going to waste, why couldn't a similar setup be used in cars for the air conditioning, making it as free as the heater is in winter?

I thinking of thrust ideas and I wonder if in proportion to fuel usage amount and the power to size ratio it makes up whick will be the best?

Hello. I am currently working on a project which requires me to design an electrical circuit. My aim is to use piezoelectric actuators in parallel (5-10 mm dia), and giving them a voltage of 9V using a signal generator. I want the actuators to vibrate in the 500-800 Hz range. Keeping in mind that I have to incorporate this in a light weight application, how do I proceed about this? Thank you.

I am trying to test a simple buck converter on 123D.circuits, but for the life of me I can't figure out how to make this work properly with NPN transistors. Lets say for the moment I want to convert 24V to 10V. Basically I want a to drive the base of an NPN transistor with a 5V control pin. The reason for this is that the 5V controller voltage is more stable than the input voltage of the buck and I don't want massive variation in my base current when it is sinking into the controller. Now the problem comes with the fact that there seems to be no good position to put a NPN transistor in the buck circuit. I have been googling around and have seen the ci…

A simple question that has always had me wondering. A broken pane invariably presents shards with smooth, perpendicular edges. A steel edge of 90 deg, even when precision ground and then honed, will not cut an unwary finger so readily as the bluntest profile in glass. The shape seems almost irrelevant to its keenness. Is it "molecular" or what? Does anybody know please?

If someone could somehow flood the frequencies of the EM spectrum with enough interference to prevent cell phones, radios and satellite signals to stop working... is it possible that other electronics could still work? (such as a computer on a hard line connected to the internet or a digital watch)