Protection Definition and 135 Threads

Hello, I'm looking for information on materials used in the nozzle thermal protection. In particular I'm interested in a protection made by different layers, an inner/outer lining, a conductive and an insulating layer, whitout rigenerative/film cooling. I would like to know typical mateials used...

The context is going down a hill in rollerblades: when people fall and they come to a quick stop (due to not having protective gear and there being lots of friction), they always end up with major injuries, while people with protective pads can sometimes fall and slide for 60+ feet and often be...

Hello, I want to learn how to design a spacecraft's thermal protection system. But I don't know where to start. Someone can help me?

Does anyone know a cheap(available on Ebay/AliExpress ) battery protection circuit board that has undervoltage/overvoltage protection and charging capability? I have a 3.7v Li-po battery and I need to draw 5 Amps from it.

A high frequency wire dipole antenna installed at 80 feet is fed with a balanced line, at the transmitter feed point is a 1:1 balun that the balanced feeline hooks to on one side, a tuner on the other. The 1:1 balun is 12 parallel turns of #12 around a ferrite core. The input to the balun has...

I came across an academic article by Mary Olson entitled "Disproportionate Impact of Radiation and Radiation Regulation" (https://www.tandfonline.com/doi/abs/10.1080/03080188.2019.1603864). Based on data in BEIR VII, she illustrates that women are more sensitive to ionizing radiation than men...

The "sleep hormone" melatonin, sold at health supplement stores, has been found to prevent radiation sickness from ionizing radiation: https://pubmed.ncbi.nlm.nih.gov/30073934/ There are also some other references for this findable with a Google search. But you don't want to be on melatonin...

My new Lenovo tablet has a "battery protection mode". This is useful for example when you want to leave it on charge almost permanently, in which case the protection mode will charge and discharge between 40% and 60% in order to maximize battery life. Is there an API that can enable/disable...

I wondered if anyone could help, I work in the fire protection industry. We currently have a project using a pressurised cylinder. The cylinder hold 200 lites of water plus 40 litres of nitrogen gas as a propellant at 10.0 bar. I’m trying to work out once the 200 litre water volume has been...

From a Science mag news article. It can also affect non-domestic cats: Apparently, nepetalactone is known to have mosquito repellent properties (similar to DEET). Not that surprising if its supposed to protect the plants from aphids.

Hello all : i am asking if there is a class of respiratory protective equipment , that can be installed inside the human body to support the normal PPE and reduce the possibility to getting infected buy some biological agent : as virus size is between 50 to 160 nm , and the first area of...

Hi. As i understand from what i have read about supercritical CO2 loops a major hurdle is erosion of the materials. especially in the hottest zones of the loop and in thin material sections and zones where the fluid changes direction or expands/compresses. But from the experiments i have read...

It has been decades since I was in electronics school and I forgot a lot. I was told using copper plug wires could hurt modern electronic ignition parts, and I was wondering if an RFI capacitor (.5 mfd.) would help protect things. I have a 4-cylinder with points that have been changed to a...

Or is that an electrocution hazard?

Hello everyone, here I have one problem, which I can not understand, can you please help me? In attachment you will find a basic star-delta diagram, with unreal calculation (Z is not real value, it's just for calculation and understanding the princip of star-delta). According to these current...

Hi, I'm learning Electrical engineering, and I'm trying to Simulate distance protection, using matlab/simulink I searched google and it has many documents about this problem, but those only show the result, and also i can't find any simulation file So i have many questions : 1. how to calculate...

There has been studies showing that high testosterone protects against cortisol. Is that why there's also a correlation between height and income? Because extremely competitive high level jobs would easily destroy a normal person's health unless they have high testosterone to protect against...

Hi everyone, I have this question attached from the ABHP exam in part B you are asked to list and justify 4 major elements for accelerator radiation protection program for this specific facility, I have written some answers which are : 1) ALARA which includes : time distance shielding source...

Good afternoon, I have installed a whole house surge protector. Can I also "double protect" a few outlets with outlet surge protectors as well? I've read where you shouldn't piggyback surge protectors and didn't know it the additional outlet protectors would interfere with the whole house...

There will be a new Planetary Protection Officer soon and changes could be happening at the Planetary Protection Office. The office makes rules concerned with potential contamination of planets with earthly life. This Science news article goes over issues (on both sides) that the office is...

There have been several stories in the news lately about swimmers getting killed by Electrical Shock Drowning (ESD) when swimming near docs in Marinas. The diagram at the following link shows how it happens, but I'm not understanding why electrical service to the docs isn't Ground Fault Circuit...

Correct me if I am wrong, but my basic understanding of how the Chronology Protection Conjecture (CPC) would work is that, as virtual particles created from the quantum fields of the vacuum would traverse a wormhole and arrive in the past, they would then travel back into the wormhole alongside...

In light of the strong desire to begin colonizing Mars in the near future, how easy will it be to remove Mars from the list of planets covered by the planetary protection treaty?

Hi, Does anyone know the reason why we use potassium iodide for thyroid protection in case of nuclear accidental event, and not sodium iodide, or lithium iodide ? (as alkali metals can give away one electron) Thanks.

In a circuit that I'm building, I have a power source of 5 volts DC that powers various components. A few of them are LED lights and light bulbs. -Background Info- In circuit 1, I have a step up buck "2A DC-DC boost step-up Conversion module MicroUSB 2-24V 3V to 5v-28V 12v 9v 24v"...

I was informed I might get a better response by posting to this forum, so sorry for the double post. Hello all, I am currently attending a service course for a PET/CT system for my employer. We have been covering the physics behind the function of detectors and my instructor said something...

Alternatives to varistors as overload protection at DC motor DC Motor here implies 12V linear actuator w/DC Motor that consumes 2.8A under loading condition. Pretty costly equipment. I'm using a L298N motor driver connected in parallel to run the linear actuator. The motor driver is run by a...

I recently received a laser cutter however, I cannot find anywhere not even in the manual what frequency it emits. It's a CO2 machine with a 180 watt laser. It's supposed to be able to cut metal. http://www.ebay.com/itm/121881769914 Can someone advise me on eye protection, I don't want to risk...

Now, first off I am punching well above my weight here but oh well. I am doing an extended project on theoretical methods of space travel and was doing some brief reading in the middle of writing about Miguel Alcubierre's warp drive for hyper fast travel within general relativity. I came across...

I have more of a discussion type question than one about Electrical Concepts (though I suppose it will devolve into that area). I've been doing a bit of reading about settingless relaying schemes and was wondering how they really improve over the traditional methods? The method of Dynamic State...

Homework Statement A three-phase distribution transformer is configured as follows: -primary side = star with solidly grounded neutral -secondary side = delta, grounded via zigzag earthing transformer A single phase-earth fault occurs on the secondary (delta) side of the circuit...

I have these great Mini-Circuits amplifier modules (ZFL-1000LN+) I use all the time that keep getting blown by a nearby HAM radio operator. Can I protect the input to this module by soldering two anti-parallel fast switching diodes from the input connection to ground?

Visual Studio is giving me the error Error 1 'System.Data.Entity.DbSet<Survey.Models.Survey>.DbSet()' is inaccessible due to its protection level c:\users\jamin\documents\visual studio 2013\Projects\Survey\Survey\Models\SurveyDbModel.cs 83 40 Survey on the line...

Hi, I need to calculate the radius of the protected area that is provided by an early streamer emission protection system according to IEC / EN 62305 standard but after hours of research I am starting to think that it is not even recognized by IEC / EN standard. So, is it?

I have no idea how lethal/strong space radiation is, but i do have an idea that most of it is from the sun perhaps? I also know that the prime factor to deflect this radiation is magnetic field and the ozone layer. I think the magnetic field handles only particle radiation and atmosphere handles...

I have installed one app in windows 7 ultimate. When I run .exe file it will open but suddenly message will come like Then i tried to change it in My computer setting that is My computer->properties->advanced system setting->advanced tab->performance setting->Data Execution Prevention->Turn on...

A recent thread talked about a radio inside a metal box. That reminds me of a question I never resolved. 9 years ago my sailboat was struck by lightning. 6 people were on board, but nobody was hurt, luckily. My mast is grounded to an underwater plate via a thick copper cable inside a plastic...

Hi, I'm just an average guy here, mostly self educated, and am looking for experts to verify my theories on developing revolutionary impact protection. If I disrupt direct impact to the head using a highly elastic layer of material, does that create an inelastic impact interruption? A helmet...

Hi, I am writing program to model the heat flow through different space shuttle tiles. I have got it working using four different methods: Forward differencing, Backward differencing, Crank-Nicolson, DuFort-Frankel and all four methods give me similar results. What are the advantages and...

Hi, I am writing a MATLAB program to model the heat flow through space shuttle tiles. Does anyone know where I can find the thermal conductivity, density and specific heat of the different tiles on a space shuttle?

Hi all. I am using LM311 comparator to design a speaker protection circuit. I read quite a few data sheet of LM311. Seems like it's such an old IC that they assume people know the IC already. I happen to be a first time user and I am not sure I design it right. Mainly strobe pin #6. From...

Homework Statement Determine RR value if the relay current has not to exceed 20mA. Neglect relay resistance. 2. The attempt at a solution I believe the solution is behind Merz-Price theorem, where the voltage system is balanced. CT1 and CT2 are identical current transformers, however, RL2...

In a differential protection relay there is a setting of a threshold for the sum of amps (or the squares). In what way would that be of interest? The relay is an Areva P521. Also, the relay can display the ratio between the positive sequence current and the negative. What information does that...

Hi, i have a 50" plasma TV with a reciever and a home theater system that I want to protect against power surge and anything else needed. I've read about stabilizers, power conditioners and line filters, but i don't know the difference between them. They all seems to do almost the same things...

Hi all, Do the changes/updates that Microsoft does periodically lower the odds of a virus successfully hurting the system? My knowledge of programming and of computers is limited, but it would seem viruses would have to be designed around the way the OS is setup. Then it would seem that a virus...

How do you protect a power supply that is floating and not connected to Earth ground. Do you still connect the ESD diodes to ground and Vcc? Are there different techniques.

So everyone has made non-Newtonian fluid at some point in their lives (when you mix corn starch and water and get that awesome liquid/solid) well in one of my classes last semester we were asked to think of ways to aid in shielding from radiation and MMOD's (Micro Meteoroids and Orbital Debris)...

As an Electrical Engineer, I am employed in a Power company. In this company, they want to create a unit for Protection which cover for both the Generation Department and the Transmission & Distribution Deparment. This is my 3rd month in the company. I was advised to make a plan on how to...

I've heard that the Earth's magnetic field protects us from radiation but am curious as to how this works. I assume it would have something to do with charged particle motion in a mag field because radiation is ionizing but I can't seem to nut out the mechanics behind it. Thanks in advance.

I just seen the Spiderman 2 movie and *SPOILER ALERT!* Gwen tells Peter to magnetize his webshooters so they won't be damaged by electro's lightning, since his webs seems to conduct electricity. Now, the explanation is that a magnetized object can hold electric charges. How is that...