My understanding was that sweating for cooling as we do is more efficient with less hair. Humans are designed to run long distances at a fairly high rate of speed. Many animals are faster in the short haul but humans can out run any creature on earth in the long haul. That running required better heat dissipation and so we lost our hair and sweated more.
Clothing and hair loss are not really related. Clothing and moving to to temperate and arctic climates are probably much more related.
There is a disease that some kids have which ruins their defenses again normal sunlight. Incandescent bulbs are safe for their parents to use as they don't produce ultraviolet light like flourescents do. This legislation would make life a bit shorter for them. They usually don't live that long to begin with.
I wonder if the state folks know about this or care?
Games, guns, cars, etc. , are all tools that can be used in various ways.
Games can be used to amuse, to teach, to kill time.
Guns can be used to defend, to intimidate, or to kill.
Cars can be used for joy rides, trips to the library, or mowing down a crowd of people.
It is my opinion that tools and the tool manufacturers should not be blaimed for illegal use of their tools.
The only exception to this rule is if a tool is so poorly designed that it can cause harm even though the user of the tool has taken reasonable precautions to obey the law and use the tool safely.
I remember the extreme clarity of the skys in the days immediatly following 9/11/2001. I live in Columbus Ohio near a medium size airport. I was amazed at how clear the skys were after the stoppage of all air travel.
If clear skys relate to energy/heat loss into space and clear skys were noticed after airline stoppage, what would you guess a major component of global warming could be?
Novell has some very large companies that use their netware. Right now I just ran a volume check on the servers where I work We have somewhere in the neighborhood of 400 Novell 4.11 servers and about 250 Novell 6.0 servers. We have about 80,000 folks that rely on these servers for doing business.
Yes, we have unix and microsoft servers as well. We have a lot more unix and ms servers than novell. Not because they are better, in my opinion, but because many of our lines of business are more familiar with MS products. The core file server and printing is done by novell because it is still the best server for that purpose.
I too, wonder if my novell experience will be worth much in the next few years. I have looked at dice and monster and you will not see much in the way of jobs for novell experienced admins and engineers.
Our company has the third largest novell server base and directory services tree in the world. GM is second and I imagine Novell is first.
I guess I answered pretty much where novell is still making their money,:).
I was reading through the messages and people seem to think that higher RPM would mean more power use. I do not think the higher RPM is much of an issue since once the spindle is up to speed it is not drawing much power anyway. What uses power on a hard drive is the motor that moves the heads across the cylinders.
A hard drive performing a seek operation has to do several things.
1. Move heads to correct physcial location on the platter. 2. Stop the heads over that location and wait for heads to stop bouncing, (you just accelerated them a bunch) 3. Maintain that position as the data is written or read. 4. Repeat until all data is written or read.
To reduce access time you need to improve a couple of things.
1. You can make the head assembly stiffer so it will bounce less. This means more mass or more expensive materails. 2.You can increase the amount of force the head moving motor can generate, making it seek faster. Once again, you increase the mass as well as increasing the current needed to perform the work. 3.You can make the heads smaller and the tracks narrower to it has to move less. Again more expensive materials required.
Spindle speed not only does not effect power consumption much it does not effect data throughput in the average read write applicaton since you are most often moving the heads and waiting for them to stop bouncing.
My guess is that SCSI drives, which on the average are of smaller capacity than IDE drives, are built with stiffer head assemblies and faster head moving motor speeds.
One other thing to consider is media quality of the hard drive platter. Most IDE drives have a built in table to track the bad spots on the platter. A normal hard drive may have many sections of bad spots that the enduser never sees since the integrated drive electronics automatically remove them from the drive's acceptable data areas. This means that you could have fragmentation due to these factory bad spots even if your drive shows no fragmentation at all.
I am guessing that SCSI drives media quality is much higher than the IDE drives because it has to be. This would result in much less hidden fragmentation.
It is the same old same old, FAST , CHEAP , GOOD. Pick any two,:).
I can only speak for the parts of the USA where I have lived and worked on house wiring. That would be Michigan and Ohio.
Most places have a copper pole driven into the ground below where the electrical meter is on the outside of the house. We also have a neutral wire coming in from the pole here in Ohio. That neutral wire is connected to the earth ground as well outside under the meter. I have seen the water supply system also tied into this neutral wire but with the advent of plastic supply lines that form of ground is also suspect.
I think what some folks fail to realize is the safety ground does not need to be a seperate ground from the neutral wire. It just needs to be a seperate wire going from the fuse/breaker box to the outlets and other junction and switch boxes. The reason it is a safety ground is that it has a less resistive path to ground than the neutral wire. This is because the neutral wire is dropping voltage due to its resistance to current flow. The safety ground is not dropping voltage across its length since there is not, or should not be, any current flowing through it. This lack of current flow means that the voltage at the safety ground is as close to zero in relationship to any hot phases being supplied as possible. This took me some thought and a few explanations to realize.
If you only relied on the neutral wire for a safety ground then the apparent ground voltage state would change as the load on the wire increased. It does not really matter if the safety ground is a seperate earth ground as long it is a seperate wire that is not carrying load current between the fuse/breaker box and the outlet box.
In the places I have done electrical work the standard is that 12 gauge wire can handle 20 amps of current safely. This gauge wire is fused with 20 amp breakers or fuses. 14 gauge wire is capable of handling up to 15 amps safely and is fused with 15 amp breakers or fuses. If you want to go up to 30 amps then you need to use 10 gauge wire and corresponding fuses and breakers.
I would disagree about wires melting only when too much current flows through them. That can be the case, of course, but there is also the situation where the wires have corroded and then the corrosion heats up due to its higher resistance and that in turn heats up the wire and or terminal. This will mean less power is being delivered to your appliance or light. That power is instead heating up a bad connection. It is these situations that a metal box can contain a fire where a plastic one will not.
Another issue is that some folks are not carefull when they strip wire. Most wires used for residential use are solid copper or aluminum. If the wires are stripped with a cutting tool a small nick or series of nicks can be made to the wire. This will cause the wire to break at that point. If the wire does not break it can be weakened and have a higher resistance at that point. This is the reaon it is wise to use a correct gauge wire stripper when taking the insulation off the wire so as to avoid nicking the wire when you remove the insulation.
In a previous comment someone said that their plastic box smelled bad and warned them that something was wrong. What if they had not been home when it smelled bad?
IMO metal boxes are a small price to pay for containing fire and providing a safety grounded enclosure.
Exactly, that was what I was trying to refer to when I said the outlets with the holes in them for the wires.
I have had to fix other folks outlets that used that style of connection. I do not know if it fails due to poor design or if there is something that is being done wrong. I only know it fails.
At least with a screw terminal you can snug them down or test them for tightness when you suspect a failing outlet or connection.
Many years ago I had a house trailer that had a fire in the back bedroom. The fire was caused by a short in a power supply that worked its way up the power cord and then into the plastic box which then caught the wall on fire.
If the metal box is not grounded properly with the safety ground then it is true it will not switch the breaker. I am talking about if everything is done correctly, in my opinion, the metal box wins as far as safety goes.
The situation where a wire is loose inside a plastic box is as you describe. What I have seen more of, however, is a bad connection inside a box which causes heat at the bad connection.
Specifically those misbegotten outlets that let people push a wire into a small hole that then catches and hopefully connects to contacts in that little hole. I much prefer the screw connection and copper wire bent just so it forms a solid contact under the screw as it is tightened.
I have a BEET degree and learned about wiring initially from watching and helping my father wire our new house after the walls and roof had been built but not closed. Dad was a cautious man as far as electrical safety.
I have a lot more tools and knowledge of how things work than Dad did but as far as practical knowledge as to what works when pulling and connecting wiring, well, I learned a lot of that by watching and doing.
I wish you luck with your plastic boxes. I do agree metal boxes can bite you with their sharp edges but I don't move so fast anymore so I will just take my time and do what I think is best.
I wonder if they ever made a ceramic electrical box? I know there were porcelin fixtures long ago but I don't think I ever saw ceramic or porcelin used as a outlet or junction box. That would be the best of both worlds as far as fire resistance and lack of sharp edges. Hmmm, dzimmerm porcelin outlet boxes. Only $10.00 a box and guaranteed to withstand up to 2000 degrees heat without catching fire. LOL. Yeah, how do you fasten the very brittle porcelin without breaking it? Wood screws, I guess.
In most residential wiring the thing you use to turn the power off to the main circuit box is the meter. You remove the meter, which by the way has a seal on it stamped by the power company, and this removes power from the two phases coming into the house. This is the only safe way to work on a main circuit panel. I do know know what kind of regualations there are where you live but in some places you can remove your own meter but not put it back. In other places you can not remove your own meter.
The reasoning behind laws in regards to not removing your own meter would probably be economic since that would be how you would steal electricy.
One point of contention I have about home wiring is the type of electrical box used to house switches, outlets, and various other junctions of wires. I am curious if anyone else agrees or disagrees with my thoughts on this matter.
The contention I have is this. I think metal boxes are much safer than plastic boxes. My reasoning is as follows.
1. With a metal box which is properly attached to the safety ground you have a situation where a live wire coming loose inside the box and hitting the box will immediately trip a circuit breaker.
2. If the live wire does not come loose but only gets flakey and hot and starts to burn your metal box will not burn along with it. It will still trip the breaker when the wire has burned enough to break free and hit the side of the box.
3. It is obvious to me that plastic boxes will not trip a breaker if a wire gets loose inside them.
4. A plastic box with a hot wire will actually burn and help in the process of burning down your house.
5. I think the only reason electricians started using plastic boxes was because there were cheaper than metal boxes.
6 Saying a plastic box is better because it insulates you and the wires inside from grounding out against the box implies total ignorance of one of the the purposes of a safety ground. It also allows shoddy wiring to go unnoticed longer.
I am not sure if your reasoning is sound. It is possible the load placed on the mitochondia could affect their efficiency?
Another thought is if doing something like this would work due to differences in the control mechanism for mitochondrial reproduction. I am hypothyroid. This means my thyroid does not produce enough thyroid hormone to keep the correct amount of mitochondria in my cells. If the control mechanism is different in Avians then how would we duplicate that? Do birds have a thyroid gland or an analog to one?
Would a hybrid human need to take a daily dose of the Avian analog to thyroid hormone to survive?
The legal system is not meant to allow something that is fair to succeed over something that is not fair. The legal system is in place to reduce the body count. If we did not have a legal way of resolving issues then lawyers and businessmen that acted unfairly would start to turn up with holes in various critical parts of their anatomy.
Legality is all about how to resolve issues without resorting to bloodshed. If you live in california you may have missed this little bit of information. It is still true though.
Justic will always prevail, it is just less messy with a legal system, IMHO.
Watching the LOTR moview requires some background from the books in order to fully appreciate what is going on in various scenes.
One comparison would be having to stop and explain the concept of god in the movie Bruce Almighty. A large number of people in the U.S.A. are familiar with the concept of god. This means the makers of a movie that have god as a participant would rely on the background people have learned over their lives. They would not need to explain what god is.
In the LOTR movies there is a vast cosmology that in some basic ways differes from our current world. If you know nothing of this cosmology then the movies may or may not be appealing to you based on the limited comprehesion and incorrect assumptions you will make due to you not possessing the needed background information.
IMHO Tolkien was a master story teller by the time he got about halfway through the two towers. The first part of the written story drags a little but once you get further into it it moves quite well. For those who like charactor development the FOTR is great charactor building information.
If you do not like to read the printed page I would recommend getting an unabridged audio tape set of the LOTR and listening to it. You could borrow such a set from a library without too much searching. www.recordedbooks.com has an unabridged reading of the complete LOTR broken into the three books. I quite enjoyed listening to the FOTR while driving back and forth to work.
If you were working for an organization that cared about finances then they would go with whatever did the job best for the least amount of money. Since you are working for a University it is likely that money is of secondary importance as it is not their money they are using.
Sometimes the budgets for Universities are determined by how much they spent in the last quarter or last year. If they spend less money then they get less money the next quarter or year.
If I were you I would try and find out what reasoning the decision maker is using. Some folks might be concerned about cost and thus your in house solution would be attractive. If the decision maker raises objections to your solution try to determine what objections they feel are most important. If the objections change as you counter them then the decision maker has a reason that they are not voicing and if you can not determine what that is you will have no way of getting the solution you think is best.
Sadly the best solution in a technical and financial sense is very seldom the best solution in a political or organizational sense.
These kinds of cards do not usually have any kind of power source. They rely on a alternating current magnetic field that the reader gives off. This magnetic field energizes the coil that is built into the card. This coil supplies power to the circuitry on the card which causes the card to send its ID via some kind of rf signal. There are no "smarts in the card itself. The card just sends its ID and a computer behind the scenes uses that ID info to open the door or pay the bill.
For those concerned about portable readers consider that a reader would have to send out a powering magnetic field and then capture the ID of the card. My guess is that all kinds of security could be built into these cards. The most obvious kind would be the use of an ID that contained a constantly changing code like the secure IDs many of us use to access various secured dialup and network devices. The only drawback is you would need some kind of contained power source in the card to power the secure ID ciruitry as it has to be constantly powered so it does not lose sychronization with the host system. My guess is the reader could still supply power for the RF signal while the secure ID part used a small lithium cell.
That way the ID would not only have to be correct but the security code would only be good for about 3 minutes. That would make these things fairly secure, probably moreso than a card and a PIN as the PIN can be noted via cameras and the quicksighted.
Physical theft of the card would be a problem but that would not be anything new to get used to.
dzimmerm
Re:using air currents to regain altitude
on
Mars Flier Prototype
·
· Score: 3, Interesting
I have a private pilots license in Gliders and Single engine land.
Most aircraft seek sinking air naturally. The reason for this is that as an airplane approaches an area of rising air the strongest rising air will lift the wing on the side that is closest to that rising air. This will cause a turn away from the rising air.
When seeking for lift as a glider pilot we use an instrument called a variometer which is a very sensistive verticle airspeed indicator. Such a device can be made audio so that glider pilots can keep their eyes out on the airspace instead of fixated on the instrument panel.
Obviously if you can make an instrument with a rising audio tone when the plane is rising and a sinking audio tone when the plane is sinking you could couple this with a computer to find lift. The rising air is also hotter than the sinking air. A thermal sensor on each wingtip would give you a direction to go to find the hottest air.
We have the technology to seek rising air but rising air is generaly caused by sunshine and it only shines for a part of the day. I have no idea if the atmosphere of Mars is simular to Earths as far as verticle air movement. A lot of what goes on in Earths atmosphere is affected by the moisture content of the air. There is a lot of heat energy that is transferred by water evaporating and condensing. This would not be present in martian air and I do not know if there is an anolog for that effect on mars. The idea of the solar powered electric motoglider that also uses rising air during the day could be helpfull in sustaining a research aircraft aloft on mars.
I am guessing that with the thinner atmosphere the landing and takeoff speeds would be higher. That could make it tricky to try and land any large size aircraft on mars. Some kind of winch or catapult might be used to launch an aircraft but that would mean a base station would be needed.
I would almost think that lots of small gliders would be better than one big one if research and survivability is what you want. Could the beach ball landing be done and then a bunch of mini/micro air probes launched? How small could you make an aircraft that could sustain itself in mars atmosphere? I have heard that the solar radiation is much more intense on the surface of mars than on earth. Does that mean more power could be gotten from solar cells?
Send a beachball lander with a couple of hundred styrofoam gliders that have solar cells with electric motors and simple cameras or other simple probes. We could take a clue from the insects and send in lots in hopes that a few will survive to fullfill their missions.
Using laptops or any other computer could reduce the amount of gasoline used to haul the student around.
With a computer you can do research that would only be possible by physically going to a library. The costs of transportation to places where you do research should be factored into the equation when determining the effect of computer use in a classroom.
Computers can allow a person who is disorganized to become more organized. The fact is that barring malfunction computers do not forget what you put into them. People do forget things. Forgetting stuff is very wastefull as it causes extra trips to be made burning up even more gasoline.
Games on computers can save gasoline also. The games will keep the students away from Malls and their arcades. Why burn gasoline to drive to the mall when you can first person shooter on your laptop. There are lots of older games that are still loads of fun that can be played on many older laptops.
Saving time by using a computer is also something to consider. Time is one thing that you can never get back. Any saving of time could be considered very important.
Most importantly of all, male geeks need more female geeks. Forcing Buffy to use a computer might get her interested in Greg the Geek rather than Fred the football player.
I am sure with a little effort you can come up with even more ways you are saving the environment by using a computer.
There are even more older and stranger things that used to run on Singer System 10 and NEC office systems. Those machines used a 60bit word composed of 10 6bit charactors. They were common in the mid to late 70s.
Sears and some Federated Dept. stores used the System 10 as their back office computer. That was when they used all singer cash registers. There was an OS involved but I can not for the life of me name it. Too many years ago.
Data General had a OS of sorts for their Nova 1200, 800, and S130 Eclipse Minis. I do not think it was unix based but I could be wrong as DG derived a lot of their stuff from DEC.
I know there are older and weirder things but they were way before my time.
More specifically when Edith Keeler asked Mr. Spock what he was doing Spock said that he was attempting to make a Mnemonic ciruit out of Stone knives and bearskins.
If I recall just before Edith came in Mr. Spock said he must have some pure solid platinum so that he could create circuits in it. Kirk responded that the paper bag contained Kirk's food, some vegtables for Spock, and all the rest of their money was used up in vacuum tubes and various other wiring components. Kirk said that it was unlikely the bag would ever contain gold, diamonds or platinum.
(This was all from memory so some divergence from the actual script is sure to happen.) I thought Joan Collins was a real Doll as Edith Keeler.
There is a downfall for putting larger and larger capacitors on the input to the 12 volt power supply.
Consider what those capacitors do. They absorb power from spikes you say. Well, The more capcitors you put on the line the more instantaneous current you will be pulling from the cars alternator. A car's alternator has diodes that convert the alternating current to DC. If you put too high a load across those diodes they will fail.
That load can be instantaneous current brought about by spikes being sucked down to 13.2 volts or whatever the battery is happy with at the temperature and current draw it is working at.
There are also theories that the charging of a lead acid battery works best if you have various spikes and sags in the incoming power. Constant pure DC tends to lower the number of cycles of charge and discharge that a battery can perform.
You are smoothing the voltage for the whole car when you smooth it for the input to your power supply with lots of capacitors unless you put a COIL in series with the input to the power supply BEFORE the capacitors. A coil used in combination with capacitors will do a better job without loading the diodes with crazy current spikes. These coils or coil will have to be made of fairly thick wire as you want them to stop the reactance,(spikes and sags), without generating their own DC voltage drop due to high resistance.
As a capacitor uses Farads a coil uses Henries. There are probably equations for figuring out what henry of coil you need for such an application. I do not remember them but I am not the one planning on frying my alternator,:^).
As another aside.
There are 400 and higher wattage inverters available. I picked up a 300 watt inverter from the local Sams club for about $30.00 USD. A few months after I purchased it I saw Sams come out with a 400 watt inverter for not much more. Technology marches on,:^) . The nice thing about inverters are that the good ones use active switching to get you the voltage and current you need rather than brute force caps and coils. A few good size caps and coils and you will have paid for that inverter and still not have a warranty.
I recall from early on in the shuttle program that there was supposed to be a tile repair kit. This kit would contain a number of tiles of different sizes along with a compound that would act to fill in the gaps around the replacement tiles.
I have done a lot of searching and have yet to find any mention of this on Google other than some loony entry about the first shuttle mission being a hush hush military job.
I thought I might have been imagining this and talked to my wife and she also remembers this tile repair kit being touted by NASA.
I listened to a radio show and a "Official" of some sort said there is no way to repair tiles in space.
I am confused as to this apparent spinning of information.
The questions are.
Is there or was there ever a real tile repair kit?
Was it abandoned for some reason if it did exsist?
Was it only a myth put out by NASA to give people hope that a missing tile would not spell death and destruction for the crew and craft?
I am 46 and so remember the start of the shuttle program quite clearly. Are there any others in my age range who recall this tile repair kit?
You can get Pre-Paid legal for yourself. If you get it through a company the company usually has a clause that you can not use the service to sue them. Since one of the most common reasons for suing is to fix money issues and since where you work is your major source of money getting PPL through your company is not a very good idea.
I have had PPL for over 5 years and I consider it a small price to pay to have what is in essense legal insurance. PPL does have a website also.
I did a quick scan and it looks like no one even mentioned Star Office. The Star Office 5.2 version works quite well on windows 98 and it includes all the normal office suite type applications including some image viewing.
Slashdot Mirror
Hair lasts between 2 to 6 years. Hair grows at about 1/4 inch to 1/2 inch a month. This does result in a terminal hair length. Hair is not forever.
dzimmerm
My understanding was that sweating for cooling as we do is more efficient with less hair. Humans are designed to run long distances at a fairly high rate of speed. Many animals are faster in the short haul but humans can out run any creature on earth in the long haul. That running required better heat dissipation and so we lost our hair and sweated more.
Clothing and hair loss are not really related. Clothing and moving to to temperate and arctic climates are probably much more related.
dzimmerm
There is a disease that some kids have which ruins their defenses again normal sunlight. Incandescent bulbs are safe for their parents to use as they don't produce ultraviolet light like flourescents do. This legislation would make life a bit shorter for them. They usually don't live that long to begin with.
I wonder if the state folks know about this or care?
dzimmerm
I use OpenBSD as a firewall and NAT box.
Games, guns, cars, etc. , are all tools that can be used in various ways.
Games can be used to amuse, to teach, to kill time.
Guns can be used to defend, to intimidate, or to kill.
Cars can be used for joy rides, trips to the library, or mowing down a crowd of people.
It is my opinion that tools and the tool manufacturers should not be blaimed for illegal use of their tools.
The only exception to this rule is if a tool is so poorly designed that it can cause harm even though the user of the tool has taken reasonable precautions to obey the law and use the tool safely.
I remember the extreme clarity of the skys in the days immediatly following 9/11/2001. I live in Columbus Ohio near a medium size airport. I was amazed at how clear the skys were after the stoppage of all air travel.
If clear skys relate to energy/heat loss into space and clear skys were noticed after airline stoppage, what would you guess a major component of global warming could be?
dzimmerm
Novell has some very large companies that use their netware. Right now I just ran a volume check on the servers where I work We have somewhere in the neighborhood of 400 Novell 4.11 servers and about 250 Novell 6.0 servers. We have about 80,000 folks that rely on these servers for doing business.
:) .
Yes, we have unix and microsoft servers as well. We have a lot more unix and ms servers than novell. Not because they are better, in my opinion, but because many of our lines of business are more familiar with MS products. The core file server and printing is done by novell because it is still the best server for that purpose.
I too, wonder if my novell experience will be worth much in the next few years. I have looked at dice and monster and you will not see much in the way of jobs for novell experienced admins and engineers.
Our company has the third largest novell server base and directory services tree in the world. GM is second and I imagine Novell is first.
I guess I answered pretty much where novell is still making their money,
dzimmerm
I was reading through the messages and people seem to think that higher RPM would mean more power use. I do not think the higher RPM is much of an issue since once the spindle is up to speed it is not drawing much power anyway. What uses power on a hard drive is the motor that moves the heads across the cylinders.
:) .
A hard drive performing a seek operation has to do several things.
1. Move heads to correct physcial location on the platter.
2. Stop the heads over that location and wait for heads to stop bouncing, (you just accelerated them a bunch)
3. Maintain that position as the data is written or read.
4. Repeat until all data is written or read.
To reduce access time you need to improve a couple of things.
1. You can make the head assembly stiffer so it will bounce less. This means more mass or more expensive materails.
2.You can increase the amount of force the head moving motor can generate, making it seek faster. Once again, you increase the mass as well as increasing the current needed to perform the work.
3.You can make the heads smaller and the tracks narrower to it has to move less. Again more expensive materials required.
Spindle speed not only does not effect power consumption much it does not effect data throughput in the average read write applicaton since you are most often moving the heads and waiting for them to stop bouncing.
My guess is that SCSI drives, which on the average are of smaller capacity than IDE drives, are built with stiffer head assemblies and faster head moving motor speeds.
One other thing to consider is media quality of the hard drive platter. Most IDE drives have a built in table to track the bad spots on the platter. A normal hard drive may have many sections of bad spots that the enduser never sees since the integrated drive electronics automatically remove them from the drive's acceptable data areas. This means that you could have fragmentation due to these factory bad spots even if your drive shows no fragmentation at all.
I am guessing that SCSI drives media quality is much higher than the IDE drives because it has to be. This would result in much less hidden fragmentation.
It is the same old same old, FAST , CHEAP , GOOD. Pick any two,
dzimmerm
I can only speak for the parts of the USA where I have lived and worked on house wiring. That would be Michigan and Ohio.
Most places have a copper pole driven into the ground below where the electrical meter is on the outside of the house. We also have a neutral wire coming in from the pole here in Ohio. That neutral wire is connected to the earth ground as well outside under the meter. I have seen the water supply system also tied into this neutral wire but with the advent of plastic supply lines that form of ground is also suspect.
I think what some folks fail to realize is the safety ground does not need to be a seperate ground from the neutral wire. It just needs to be a seperate wire going from the fuse/breaker box to the outlets and other junction and switch boxes. The reason it is a safety ground is that it has a less resistive path to ground than the neutral wire. This is because the neutral wire is dropping voltage due to its resistance to current flow. The safety ground is not dropping voltage across its length since there is not, or should not be, any current flowing through it. This lack of current flow means that the voltage at the safety ground is as close to zero in relationship to any hot phases being supplied as possible. This took me some thought and a few explanations to realize.
If you only relied on the neutral wire for a safety ground then the apparent ground voltage state would change as the load on the wire increased. It does not really matter if the safety ground is a seperate earth ground as long it is a seperate wire that is not carrying load current between the fuse/breaker box and the outlet box.
In the places I have done electrical work the standard is that 12 gauge wire can handle 20 amps of current safely. This gauge wire is fused with 20 amp breakers or fuses. 14 gauge wire is capable of handling up to 15 amps safely and is fused with 15 amp breakers or fuses. If you want to go up to 30 amps then you need to use 10 gauge wire and corresponding fuses and breakers.
I would disagree about wires melting only when too much current flows through them. That can be the case, of course, but there is also the situation where the wires have corroded and then the corrosion heats up due to its higher resistance and that in turn heats up the wire and or terminal. This will mean less power is being delivered to your appliance or light. That power is instead heating up a bad connection. It is these situations that a metal box can contain a fire where a plastic one will not.
Another issue is that some folks are not carefull when they strip wire. Most wires used for residential use are solid copper or aluminum. If the wires are stripped with a cutting tool a small nick or series of nicks can be made to the wire. This will cause the wire to break at that point. If the wire does not break it can be weakened and have a higher resistance at that point. This is the reaon it is wise to use a correct gauge wire stripper when taking the insulation off the wire so as to avoid nicking the wire when you remove the insulation.
In a previous comment someone said that their plastic box smelled bad and warned them that something was wrong. What if they had not been home when it smelled bad?
IMO metal boxes are a small price to pay for containing fire and providing a safety grounded enclosure.
dzimmerm
Exactly, that was what I was trying to refer to when I said the outlets with the holes in them for the wires.
I have had to fix other folks outlets that used that style of connection. I do not know if it fails due to poor design or if there is something that is being done wrong. I only know it fails.
At least with a screw terminal you can snug them down or test them for tightness when you suspect a failing outlet or connection.
dzimmerm
Many years ago I had a house trailer that had a fire in the back bedroom. The fire was caused by a short in a power supply that worked its way up the power cord and then into the plastic box which then caught the wall on fire.
If the metal box is not grounded properly with the safety ground then it is true it will not switch the breaker. I am talking about if everything is done correctly, in my opinion, the metal box wins as far as safety goes.
The situation where a wire is loose inside a plastic box is as you describe. What I have seen more of, however, is a bad connection inside a box which causes heat at the bad connection.
Specifically those misbegotten outlets that let people push a wire into a small hole that then catches and hopefully connects to contacts in that little hole. I much prefer the screw connection and copper wire bent just so it forms a solid contact under the screw as it is tightened.
I have a BEET degree and learned about wiring initially from watching and helping my father wire our new house after the walls and roof had been built but not closed. Dad was a cautious man as far as electrical safety.
I have a lot more tools and knowledge of how things work than Dad did but as far as practical knowledge as to what works when pulling and connecting wiring, well, I learned a lot of that by watching and doing.
I wish you luck with your plastic boxes. I do agree metal boxes can bite you with their sharp edges but I don't move so fast anymore so I will just take my time and do what I think is best.
I wonder if they ever made a ceramic electrical box? I know there were porcelin fixtures long ago but I don't think I ever saw ceramic or porcelin used as a outlet or junction box. That would be the best of both worlds as far as fire resistance and lack of sharp edges. Hmmm, dzimmerm porcelin outlet boxes. Only $10.00 a box and guaranteed to withstand up to 2000 degrees heat without catching fire. LOL. Yeah, how do you fasten the very brittle porcelin without breaking it? Wood screws, I guess.
dzimmerm
In most residential wiring the thing you use to turn the power off to the main circuit box is the meter. You remove the meter, which by the way has a seal on it stamped by the power company, and this removes power from the two phases coming into the house. This is the only safe way to work on a main circuit panel. I do know know what kind of regualations there are where you live but in some places you can remove your own meter but not put it back. In other places you can not remove your own meter.
The reasoning behind laws in regards to not removing your own meter would probably be economic since that would be how you would steal electricy.
One point of contention I have about home wiring is the type of electrical box used to house switches, outlets, and various other junctions of wires. I am curious if anyone else agrees or disagrees with my thoughts on this matter.
The contention I have is this. I think metal boxes are much safer than plastic boxes. My reasoning is as follows.
1. With a metal box which is properly attached to the safety ground you have a situation where a live wire coming loose inside the box and hitting the box will immediately trip a circuit breaker.
2. If the live wire does not come loose but only gets flakey and hot and starts to burn your metal box will not burn along with it. It will still trip the breaker when the wire has burned enough to break free and hit the side of the box.
3. It is obvious to me that plastic boxes will not trip a breaker if a wire gets loose inside them.
4. A plastic box with a hot wire will actually burn and help in the process of burning down your house.
5. I think the only reason electricians started using plastic boxes was because there were cheaper than metal boxes.
6 Saying a plastic box is better because it insulates you and the wires inside from grounding out against the box implies total ignorance of one of the the purposes of a safety ground. It also allows shoddy wiring to go unnoticed longer.
Those are my reasons, what do you think?
dzimmerm
I am not sure if your reasoning is sound. It is possible the load placed on the mitochondia could affect their efficiency?
Another thought is if doing something like this would work due to differences in the control mechanism for mitochondrial reproduction. I am hypothyroid. This means my thyroid does not produce enough thyroid hormone to keep the correct amount of mitochondria in my cells. If the control mechanism is different in Avians then how would we duplicate that? Do birds have a thyroid gland or an analog to one?
Would a hybrid human need to take a daily dose of the Avian analog to thyroid hormone to survive?
Just some thoughts.
dzimmerm
The legal system is not meant to allow something that is fair to succeed over something that is not fair. The legal system is in place to reduce the body count. If we did not have a legal way of resolving issues then lawyers and businessmen that acted unfairly would start to turn up with holes in various critical parts of their anatomy.
Legality is all about how to resolve issues without resorting to bloodshed. If you live in california you may have missed this little bit of information. It is still true though.
Justic will always prevail, it is just less messy with a legal system, IMHO.
dzimmerm
Watching the LOTR moview requires some background from the books in order to fully appreciate what is going on in various scenes.
One comparison would be having to stop and explain the concept of god in the movie Bruce Almighty. A large number of people in the U.S.A. are familiar with the concept of god. This means the makers of a movie that have god as a participant would rely on the background people have learned over their lives. They would not need to explain what god is.
In the LOTR movies there is a vast cosmology that in some basic ways differes from our current world. If you know nothing of this cosmology then the movies may or may not be appealing to you based on the limited comprehesion and incorrect assumptions you will make due to you not possessing the needed background information.
IMHO Tolkien was a master story teller by the time he got about halfway through the two towers. The first part of the written story drags a little but once you get further into it it moves quite well. For those who like charactor development the FOTR is great charactor building information.
If you do not like to read the printed page I would recommend getting an unabridged audio tape set of the LOTR and listening to it. You could borrow such a set from a library without too much searching. www.recordedbooks.com has an unabridged reading of the complete LOTR broken into the three books. I quite enjoyed listening to the FOTR while driving back and forth to work.
That is my two pence worth. YMMV.
dzimmerm
If you were working for an organization that cared about finances then they would go with whatever did the job best for the least amount of money. Since you are working for a University it is likely that money is of secondary importance as it is not their money they are using.
Sometimes the budgets for Universities are determined by how much they spent in the last quarter or last year. If they spend less money then they get less money the next quarter or year.
If I were you I would try and find out what reasoning the decision maker is using. Some folks might be concerned about cost and thus your in house solution would be attractive. If the decision maker raises objections to your solution try to determine what objections they feel are most important. If the objections change as you counter them then the decision maker has a reason that they are not voicing and if you can not determine what that is you will have no way of getting the solution you think is best.
Sadly the best solution in a technical and financial sense is very seldom the best solution in a political or organizational sense.
Good luck
dzimmerm
These kinds of cards do not usually have any kind of power source. They rely on a alternating current magnetic field that the reader gives off. This magnetic field energizes the coil that is built into the card. This coil supplies power to the circuitry on the card which causes the card to send its ID via some kind of rf signal. There are no "smarts in the card itself. The card just sends its ID and a computer behind the scenes uses that ID info to open the door or pay the bill.
For those concerned about portable readers consider that a reader would have to send out a powering magnetic field and then capture the ID of the card. My guess is that all kinds of security could be built into these cards. The most obvious kind would be the use of an ID that contained a constantly changing code like the secure IDs many of us use to access various secured dialup and network devices. The only drawback is you would need some kind of contained power source in the card to power the secure ID ciruitry as it has to be constantly powered so it does not lose sychronization with the host system. My guess is the reader could still supply power for the RF signal while the secure ID part used a small lithium cell.
That way the ID would not only have to be correct but the security code would only be good for about 3 minutes. That would make these things fairly secure, probably moreso than a card and a PIN as the PIN can be noted via cameras and the quicksighted.
Physical theft of the card would be a problem but that would not be anything new to get used to.
dzimmerm
I have a private pilots license in Gliders and Single engine land.
Most aircraft seek sinking air naturally. The reason for this is that as an airplane approaches an area of rising air the strongest rising air will lift the wing on the side that is closest to that rising air. This will cause a turn away from the rising air.
When seeking for lift as a glider pilot we use an instrument called a variometer which is a very sensistive verticle airspeed indicator. Such a device can be made audio so that glider pilots can keep their eyes out on the airspace instead of fixated on the instrument panel.
Obviously if you can make an instrument with a rising audio tone when the plane is rising and a sinking audio tone when the plane is sinking you could couple this with a computer to find lift. The rising air is also hotter than the sinking air. A thermal sensor on each wingtip would give you a direction to go to find the hottest air.
We have the technology to seek rising air but rising air is generaly caused by sunshine and it only shines for a part of the day. I have no idea if the atmosphere of Mars is simular to Earths as far as verticle air movement. A lot of what goes on in Earths atmosphere is affected by the moisture content of the air. There is a lot of heat energy that is transferred by water evaporating and condensing. This would not be present in martian air and I do not know if there is an anolog for that effect on mars. The idea of the solar powered electric motoglider that also uses rising air during the day could be helpfull in sustaining a research aircraft aloft on mars.
I am guessing that with the thinner atmosphere the landing and takeoff speeds would be higher. That could make it tricky to try and land any large size aircraft on mars. Some kind of winch or catapult might be used to launch an aircraft but that would mean a base station would be needed.
I would almost think that lots of small gliders would be better than one big one if research and survivability is what you want. Could the beach ball landing be done and then a bunch of mini/micro air probes launched? How small could you make an aircraft that could sustain itself in mars atmosphere? I have heard that the solar radiation is much more intense on the surface of mars than on earth. Does that mean more power could be gotten from solar cells?
Send a beachball lander with a couple of hundred styrofoam gliders that have solar cells with electric motors and simple cameras or other simple probes. We could take a clue from the insects and send in lots in hopes that a few will survive to fullfill their missions.
dzimmerm
Using laptops or any other computer could reduce the amount of gasoline used to haul the student around.
With a computer you can do research that would only be possible by physically going to a library. The costs of transportation to places where you do research should be factored into the equation when determining the effect of computer use in a classroom.
Computers can allow a person who is disorganized to become more organized. The fact is that barring malfunction computers do not forget what you put into them. People do forget things. Forgetting stuff is very wastefull as it causes extra trips to be made burning up even more gasoline.
Games on computers can save gasoline also. The games will keep the students away from Malls and their arcades. Why burn gasoline to drive to the mall when you can first person shooter on your laptop. There are lots of older games that are still loads of fun that can be played on many older laptops.
Saving time by using a computer is also something to consider. Time is one thing that you can never get back. Any saving of time could be considered very important.
Most importantly of all, male geeks need more female geeks. Forcing Buffy to use a computer might get her interested in Greg the Geek rather than Fred the football player.
I am sure with a little effort you can come up with even more ways you are saving the environment by using a computer.
dzimmerm
There are even more older and stranger things that used to run on Singer System 10 and NEC office systems. Those machines used a 60bit word composed of 10 6bit charactors. They were common in the mid to late 70s.
Sears and some Federated Dept. stores used the System 10 as their back office computer. That was when they used all singer cash registers. There was an OS involved but I can not for the life of me name it. Too many years ago.
Data General had a OS of sorts for their Nova 1200, 800, and S130 Eclipse Minis. I do not think it was unix based but I could be wrong as DG derived a lot of their stuff from DEC.
I know there are older and weirder things but they were way before my time.
More specifically when Edith Keeler asked Mr. Spock what he was doing Spock said that he was attempting to make a Mnemonic ciruit out of Stone knives and bearskins.
If I recall just before Edith came in Mr. Spock said he must have some pure solid platinum so that he could create circuits in it. Kirk responded that the paper bag contained Kirk's food, some vegtables for Spock, and all the rest of their money was used up in vacuum tubes and various other wiring components. Kirk said that it was unlikely the bag would ever contain gold, diamonds or platinum.
(This was all from memory so some divergence from the actual script is sure to happen.) I thought Joan Collins was a real Doll as Edith Keeler.
There is a downfall for putting larger and larger capacitors on the input to the 12 volt power supply.
:^) .
:^) . The nice thing about inverters are that the good ones use active switching to get you the voltage and current you need rather than brute force caps and coils. A few good size caps and coils and you will have paid for that inverter and still not have a warranty.
Consider what those capacitors do. They absorb power from spikes you say. Well, The more capcitors you put on the line the more instantaneous current you will be pulling from the cars alternator. A car's alternator has diodes that convert the alternating current to DC. If you put too high a load across those diodes they will fail.
That load can be instantaneous current brought about by spikes being sucked down to 13.2 volts or whatever the battery is happy with at the temperature and current draw it is working at.
There are also theories that the charging of a lead acid battery works best if you have various spikes and sags in the incoming power. Constant pure DC tends to lower the number of cycles of charge and discharge that a battery can perform.
You are smoothing the voltage for the whole car when you smooth it for the input to your power supply with lots of capacitors unless you put a COIL in series with the input to the power supply BEFORE the capacitors. A coil used in combination with capacitors will do a better job without loading the diodes with crazy current spikes. These coils or coil will have to be made of fairly thick wire as you want them to stop the reactance,(spikes and sags), without generating their own DC voltage drop due to high resistance.
As a capacitor uses Farads a coil uses Henries. There are probably equations for figuring out what henry of coil you need for such an application. I do not remember them but I am not the one planning on frying my alternator,
As another aside.
There are 400 and higher wattage inverters available. I picked up a 300 watt inverter from the local Sams club for about $30.00 USD. A few months after I purchased it I saw Sams come out with a 400 watt inverter for not much more. Technology marches on,
Good Luck,
dzimmerm
I recall from early on in the shuttle program that there was supposed to be a tile repair kit. This kit would contain a number of tiles of different sizes along with a compound that would act to fill in the gaps around the replacement tiles.
I have done a lot of searching and have yet to find any mention of this on Google other than some loony entry about the first shuttle mission being a hush hush military job.
I thought I might have been imagining this and talked to my wife and she also remembers this tile repair kit being touted by NASA.
I listened to a radio show and a "Official" of some sort said there is no way to repair tiles in space.
I am confused as to this apparent spinning of information.
The questions are.
Is there or was there ever a real tile repair kit?
Was it abandoned for some reason if it did exsist?
Was it only a myth put out by NASA to give people hope that a missing tile would not spell death and destruction for the crew and craft?
I am 46 and so remember the start of the shuttle program quite clearly. Are there any others in my age range who recall this tile repair kit?
dzimmerm
You can get Pre-Paid legal for yourself. If you get it through a company the company usually has a clause that you can not use the service to sue them. Since one of the most common reasons for suing is to fix money issues and since where you work is your major source of money getting PPL through your company is not a very good idea.
I have had PPL for over 5 years and I consider it a small price to pay to have what is in essense legal insurance. PPL does have a website also.
http://www.prepaidlegal.com
dzimmerm
I did a quick scan and it looks like no one even mentioned Star Office. The Star Office 5.2 version works quite well on windows 98 and it includes all the normal office suite type applications including some image viewing.
dzimmerm