Engineering

One of the ways to increase energy density of a capacitor is to increase dielectric permittivity of the dielectric. Some sources claim that when some materials (for example some ferroelectrics) approach Curie point their dielectric permittivity start to approach infinity. What happens to dielectric strengths and energy density then? Metals demonstrate infinite dielectric permittivity. What if we take a metal plate completely embedded in dielectric (for example a ceramics) and place it between two capacitor plates? Another way to increase energy density is to increase capacitor plates surface area. What if we use cermet for electrodes in a dielectric capacitor? Cermet…

Hi I have a concept for a device to assist in a manufacturing process that would require a hand held electro-magnetic device. (Not fixed magnet) (I would prefer not to discuss the actual process for confidentiality reasons) The device needs to be hand held - not a robot arm. The device needs to be comfortable to hold and move about for short periods of time (I'm thinking weighing less than 1lb in total including power source) (Must be battery powered) I'm looking to develop as high a field strength as possible as the higher the better - also if it can be focussed to some degree that would help. Whilst I have electronics skills I have no practical experien…

I am making a generator. The power it produces is 12v dc which means I can't run anything that uses 110v AC I was wondering if I could use the step-down transformer in a cell phone charger that has an output of 12v dc and an input of 110vac and reverse the input and output to turn 12vdc into 110vac. Would this work if not have any other ideas that aren't to complex or costly.

I'm looking to setup a homemade CRT experiment, for two purposes the first is of course the standard tests for observation but the second and main reason why I'm looking to do this I will now explain: From what I have managed to assertain Magnets are able to affect the electrons passing in the tube, and what from that it is my understanding that the electrons should be capable of inducing an electric current within a copper coil that is wrapped around the head of the tube. I am here to ask for the opinion and knowledge of the community members in regards to this, and whether or not this is an accurate assumption to make. I have far too many projects, most of which I'…

I am a Science student in school, I have interest in Electronics. And I want to build some projects using Arduino and Raspberry pi, for my school exhibition. But I am confused, which board to use, like I want build a robot who, recognize the faces of persons and speaks their names. As far I searched, I am very confused between two boards, I am good at C++, so I should use Arduino, but people suggest me to use Raspberry, can anyone guide me which board to use, for which project. This robot is just a example, i have some more project ideas in my mind, so some general idea is needed for choosing between these two. Please help me out to find out. Thanks

We are solving for X, X is a device or combination of components which satisfies the requirements. Given: I have a limited source power (ie, 1W) I have unlimited resources to design electrical components and unlimited time. Requirement: device must output a 10J pulse. Allowances, For my math to work, the device can accept 1W for 10 seconds to be able to output the 10J during a 1 second cycle, assuming no losses, no resistance, etc. Does a Marx Generator do this? What X device satisfies this requirement?

Hello everybody! This shall be an analog-to-digital converter (Adc) for radiofrequencies. Up to now they're "Flash" converters or similar, whose dynamic range doesn't fulfil radiofrequency desires, because their complexity and the offset and 1/F noise limit them, especially if using the fastest components. My proposal instead uses several stages that are Ac-coupled to remove the offset and 1/F noise, where every stage contributes the digital output and has a modest gain. It is similar to a "logarithmic amplifier" (not the one with an op amp, but the amplifier-detector formerly used in radars and spectrum analyzers) like the LT5538 http://www.linear.com/docs/26333block d…

what is this space for ? it looks like an elevator well ? or what else ? and the pic is taken from the top ?

Seen some orientals propelling their small boats with a single oar 'yuloh' at the transom, on 'Z' motion. ----> http://www.simplicityboats.com/1Scullings.jpg Would there be an advantage of the oar paddle being flexible, as a fish/whale tailfin propulsion, not for 'Z' motion ?

Does anyone know where in the Unites States Digital writing pen company is? I live in North Carolina and haven't a clue where to look? I also would like to invent a new Digital writing pen with cover, but who can to trust these days? curious

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…