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# CFL's not a bright idea

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Several countries in the world are currently in the process of making ordinary incandescent light bulbs illegal. The USA, Australia, and the UK, have all already had laws come into effect that limit the manufacture or sale of certain wattages of the bulbs. Argentina has already made the sale of incandescent bulbs illegal. In the USA, manufacture of the 100 and 70 watt bulbs are already illegal, and manufacture of both the 60 and 40 watts will, under the current law, be also be illegal in 2014.

The whole intention of these laws are to reduce the consumption of energy. But does this really make sense? There are, for example, other ways to reduce energy consumption, such as just taxing electricity.

The manufacture of the bulb itself consumes energy. It takes several times as much energy to produce a compact fluorescent bulb as an incandescent bulb. Furthermore, because of the use of potentially toxic mercury in fluorescent bulbs and the stringent environmental regulations, manufacturers in the USA are unnable to compete with Chinese manufacturers. So whereas around half the old incandescent bulbs are still produced in the USA, all of the new compact fluorescent lights are produced in China. The energy consumption for manufacturing in China is much more wasteful and less efficient than in the USA. The fact that the Chinese government subsidizes the prices of electric power does not help. 68.7% of the electric power in China is produced from coal power plants, which are often much less efficient more polluting than those in the USA. Indeed, China is the largest consumer of coal in the world. The coal power plants in China use bituminous coal which, while cheaper than other grades of coal, also has a much higher sulfur content leading to acid rain.

The mere production of the new compact fluorescent bulbs consumes 1.7 kiloWatts of power per bulb. This is not electric power from the USA, but rather electric power from China that results in much more pollution and carbon dioxide emissions. So the new laws are not only resulting in more pollution, but also the loss of more American jobs.

Then there is cost. A typical compact fluorescent bulb costs three times as much as an incandescent bulb. While suppossedly fluorescent bulbs can last 8 times longer than the old incandescent bulbs, in practice most of the compact fluorescent bulbs coming from China are of inferior quality, and it is my experience that they only tend to last between 1.5 to 3 times as long. Their rated lifespans will be reduced even more if put on a dimmer switch. If you go to the store and find that compact fluorescent bulbs are the same price as the old incandescent bulbs, it is not because they are actually cheaper. Rather, the taxpayers are indirectly subsidizing the difference of cost through grants to local utility companies. Compact fluorescent bulbs also are intended to be specially disposed of, because of their mercury content. Taking the trouble to properly recycle the bulbs and prevent the glass from breaking also adds cost, trouble, and indirectly consumes more energy.

Now to bring up the subject of energy efficiency. It is widely claimed that compact fluorescent bulbs use 70% less energy than ordinary incandescent bulbs. But this is only in terms of light output. It actuality, incandescent bulbs are essentially 100% efficient. It is just that most of the energy output is in the form of heat rather than light. Because of geographic distribution, most American households use more energy heating their homes than air conditioning. So it makes little sense to be using fluorescent lighting for most of these households. Why go to the trouble of trying to avoid electric power from being converted to heat in the lighting while simultaneously separately consuming electric power to generate heat? It makes no sense. Even in warmer locations, lights are typically used most in the night time, when it also happens to be colder. Even most homes in the "sun belt" have their heaters turned on at night in the winter. So compact fluroescent bulbs, in many situations, will not reduce the consumption of energy. They will produce less heat, and people will just turn up the setting on their heaters to compensate.

just found this from a pro-CFL cite:

Myth: CFLs don't save money because my heating system has to work harder to produce the lost heat I would have received from my regular incandescent.

Reality: The heat lost when switching from an incandescent to a CFL has a negligible effect on your heating system.The heat that emanates from incandescent bulbs tends to hang up near the ceiling, and has little effect on your thermostat.

What a lame defense! Looks like they are really trying hard to counter the anti-CFL movement. Even if the effect truely is "negligible", one could logically argue that the potential energy saving themselves from CFL are also "negligible" compared to the energy consumption of the heating system. In any case, this does nothing to adress the original argument itself: that it is pointless to try to prevent electric power from being converted to heat while one is also using energy to heat the home at the same time. I suppose an argument could be made if only using a wood burning fireplace to heat the home (biofuel), but how many commonly people do that? All heat tends to rise upward toward the ceilling. A heating system typically has a fan that pushes the air around. This movement of air will also push around the air towards the ceilling. And if the air near the ceilling is already warm, it will just prevent more of the warm air from the heater from also similarly rising and being "wasted".

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Well I have commenced replacing incandescent light sources with LEDs.

Unfortunately these are also largely made in the Far East.

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http://www.huffingto...s_n_895133.html

http://articles.lati...-bulbs-20110713

The USA has already passed legislation that is already in the process of making the sale or manufacture of normal incandescent lightbulbs illegal. Several congressmen attempted to overturn the ban, but failed to obtain the necessary two-thirds majority.

As of this time, both 100 Watt and 70 Watt incandescent bulbs have dissappeared from the shelves in American stores. The 45 Watt bulb will also be banned in a few years.

Good incandescent lightbulbs that have a long history of success

This is completely ridiculous, the government telling people what products they are not allowed to use. There is nothing wrong with incandescent bulbs. The government should not have any right to force people to use a different product just because they want to force people to use less energy! Someone who is careful to turn off their incandescent lights when they are not in the room is still using less energy than someone with "energy-saving" lights who leaves all the lights in their house on. What is next, is the government going to force Americans to install motion detectors to automatically turn off lights when no one is in the room?

I absolutely HATE fluorescent lights that the government is trying to push on everyone. The light has an eery tint, and it is more difficult for me to concentrate because there is actually high frequency flickering, although most people are unable to consciously discern this. And of course, some people with pets or small children are concerned about the mercury vapor that could be released if the lightbulb breaks (and it typically does break when put in the trash, realistically not many people are going to properly dispose of these new bulbs).

The only alternative, LED lighting, is even more efficient than fluorescent, but is unfortunately ridiculously expensive (60 dollars for a bulb that would match the light output of a 75 Watt incandescent bulb).

I imagine this lightbulb ban could spawn a thriving black market in the USA. Perhaps we will even see violence associated with organised light bulb crime!

The argument about saving energy is not a particularly good one. Household lighting only composes a very small fraction of the total energy consumed. In a typical household, normal incandescent lighting consumes only 15% of the home's electric power use. In fact, home heating consumes around HALF of a typical household's electricity use. Most of the American population lives in in the north half of the country, where the climate tends to be cooler. For a house with its heater on, "energy saving" CF bulbs will NOT actually save any energy. All types of lighting are actually 100% "efficient", it is just a matter of how much energy is converted into light and how much into heat. Forcing households in Minnessota or New York to convert to fluorescent bulbs is completely senseless.

I think the liberal environmental mantra says it all: "Live more simply so that all may live". If the impact of my using incandescent bulbs is too intolerable on the environment, I say perhaps there are just TOO MANY PEOPLE on the earth. These environmentalists should start focusing on population control instead of the regulation invassion on my home.

http://freedomlightb...ight-bulbs.html

a particular rundown of why the society energy savings are not there

video:

Here are the relevent excerpts from the abominable law:

(ii) INTERMEDIATE BASE INCANDESCENT LAMPS.—

An intermediate base incandescent lamp shall not

exceed 40 rated watts.

(v) BACKSTOP REQUIREMENT.—

[. . . ]

if the final rule does not

produce savings that are greater than or equal to the

savings from a minimum efficacy standard of 45

lumens per watt, effective beginning January 1, 2020,

the Secretary shall prohibit the sale of any general

service lamp that does not meet a minimum efficacy

standard of 45 lumens per watt.

Energy Independence and Security Act of 2007, Title III: Energy Savings Though Improved Standards for Appliance and Lighting,

B. Lighting Energy Efficiency

I have tried to read the whole Act, but the wording is so obtuse, and the law ridiculously complex. I believe these two excerpts are the primary references affecting normal incandescent light bulbs.

video:

Admittingly, there is plenty of very misleading information being thrown out by both sides. Unfortunately that Energy Independence and Security Act actually allocated funding for public educating about "energy saving". Essentially the taxpayer is subsidizing millions of dollars in propaganda in favor of CFL's. Even on the official government website there were several blatent lies about CFL's.

Edited by Anders Hoveland
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Did you not see my post or do you not want to hold a discussion?

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Incandescent bulbs have not been banned in the US, it's just that the ones that can now be sold must meet efficiency standards. The "normal" ones, i.e. based on ~100 year-old technology, have an efficiency of a few percent. Basically they are heaters with the side-effect of producing some visible light. Efficiency standards have been implemented for a variety of appliances and other consumer goods. It's not like light bulbs are being singled out.

Now it's true that the energy savings with regard to heating is zero. Heating is generally very efficient because the waste product of the thermodynamic process is the actual product. It's when you use air conditioning — and you do use it even in northern climates like New York — that the savings come in. Cooling can't be nearly as close to 100% efficient as heating. But because you aren't heating as much you save that energy, and you save the energy you'd need to remove that excess heat, so you more than double the savings. It's more like tripling.

The mere production of the new compact fluorescent bulbs consumes 1.7 kiloWatts of power per bulb.

This is a nonsensical statement.

The only alternative, LED lighting, is even more efficient than fluorescent, but is unfortunately ridiculously expensive (60 dollars for a bulb that would match the light output of a 75 Watt incandescent bulb).

This is wrong, twofold. The LED bulbs are cheaper, and it's not the only alternative. A year ago the LED bulb you describe was available for under $40. http://news.cnet.com/8301-11128_3-20081410-54/philips-75-watt-led-for-sale-for-$39.97/

You can get high-efficiency incandescent bulbs.

http://www.nrdc.org/energy/lightbulbs/

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Incandescent bulbs have not been banned in the US, it's just that the ones that can now be sold must meet efficiency standards.

You can get high-efficiency incandescent bulbs.

http://www.nrdc.org/energy/lightbulbs/

These are both essentially LIES !!!

Incandescent bulbs are already in the process of becoming banned. The law, already passed, will demand regular fixture light bulbs must meet at least 45 lumens per Watt. It is practically impossible for incandescent, even halogen hulbs to meet this. A quartz halogen bulb (high-efficiency incandescent) typically produces 24 lumens per Watt, while even the high temperature halogen bulbs (which are not commonly available) only reach 35 lumens per Watt. So regular incandescent bulbs are essentially being banned.

If you do not believe me, go to your store and try to find any 100 Watt normal incandescent light for sale. The 70 Watt incandescent bulbs are already dissappearing from the shelves, and soon the 45 Watt ones will be banned also.

I am tired of people falsely claiming the bulbs will not be banned. The exact language of the law is extremely complicated and misleading, and it does not specifically mention that incandescents will be banned, but that is the effect of the law. Now whether the federal government actually has the authority to regulate lighting efficiency standards is a different matter, it is possible the Supreme Court may restrict the enforcement of the law if it feels the federal government is overstretching the authority granted to it through the commerce clause in the Constitution. But most stores and factories are not going to want to risk legal trouble.

This is a nonsensical statement.

Correct, my mistake. Perhaps the figure is 1.7 kiloJoules ? That would be the equivalent of 1000 hours of use.

Manufacturers usually claim that their CFL's have a lifetime of 5000 hours, but this is often a lie. Many of the cheaper CFL's have a lifetimes as low has 2500 hours. I am surprised there has not been any class action lawsuits against these companies yet. Many of these companies are using inferior electronic parts that cause the bulb to fail early, not just because it is cheaper, but also because they can sell more bulbs that way. Remember, all these bulbs are made in Chinese factories, and we all know Chinese companies have much lower ethical standards.

One source I found stated that producing a compact fluorescent bulb consumes about five times as much energy as it takes to make an incandescent bulb.

Here is one comment made by James Rhyner at St. Cloud University:

"I have been trying CFL's for several years and have yet to have one that lasts longer than an incandescent bulb. Again the politicians are trying to run our lives. As another writer mentions, the costs of producing and disposing of the CFL's are probably much greater than the operating and disposal costs of incandescents. Of course no one wants to analyze that as the politicians will lose their kick backs from the Chinese manufacturers (I despise congress and don't trust them)"

(December 15, 2011)

"I have a combination of incandescent and CFL bulbs. ... My home was built in 1999, and all the bulbs in it are 60-watt bulbs. Just in the last year they started to burn out. 11 years for an incandescent bult is pretty darn good. I have replaced some of these with CFL's and NONE of them have lasted more than 3 years."

(Darryl Buss, comment left on Popular Mechanics website)

Exaggerated lifespan

Real-world reports from the home front show that the claimed extended lifespan of CFLs is often greatly exaggerated. There is ample data indicating that the frequent switching on and off of CFLs greatly shortens their life. A study by H. Sterling Burnett, senior fellow at the National Center for Policy Analysis, and co-author Amanda Berg concludes:

“Unfortunately, except under a fairly narrow range of circumstances, CFLs are less efficient than advertised. Manufacturers claim the average life span of a CFL bulb is 10,000 hours. However, in many applications the life and energy savings of a CFL are significantly lower. Applications in which lighting is used only briefly (such as closets, bathrooms, motion detectors and so forth) will cause CFL bulbs to burn out as quickly as regular incandescent bulbs . . . When initially switched on, CFLs may provide as little as 50 percent to 80 percent of their rated light output and can take up to three minutes to reach full brightness.”

http://www.ncpa.org/pub/ba637/

Edited by Anders Hoveland
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These are both essentially LIES !!!

When someone else quotes a (possibly) inaccurate figure they are lies.

Correct, my mistake.

When you quote one it is a mere human mistake.

That approach will not win friends an influence people.

Furthermore you have made at least one more 'mistake'

The only alternative, LED lighting, is even more efficient than fluorescent, but is unfortunately ridiculously expensive (60 dollars for a bulb that would match the light output of a 75 Watt incandescent bulb).

LED, flourescent and incandescent are not the only forms of lighting.

The shame is that I actually agree that choice should be maintained in the type of lightsource available.

Edited by studiot
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These are both essentially LIES !!!

Incandescent bulbs are already in the process of becoming banned. The law, already passed, will demand regular fixture light bulbs must meet at least 45 lumens per Watt. It is practically impossible for incandescent, even halogen hulbs to meet this. A quartz halogen bulb (high-efficiency incandescent) typically produces 24 lumens per Watt, while even the high temperature halogen bulbs (which are not commonly available) only reach 35 lumens per Watt. So regular incandescent bulbs are essentially being banned.

I can only assume you are using a definition of essentially that means "not, but I don't have an actual, factual counterargument". You are shifting the goalposts from "incandescents" to "regular incandescents" and back when it suits you. Incandescent bulbs are not being banned. This is not a lie.

If you do not believe me, go to your store and try to find any 100 Watt normal incandescent light for sale. The 70 Watt incandescent bulbs are already dissappearing from the shelves, and soon the 45 Watt ones will be banned also.

I wasn't talking about the "normal" ones, which are very inefficient. See the above objection to moving the goalposts.

I am tired of people falsely claiming the bulbs will not be banned. The exact language of the law is extremely complicated and misleading, and it does not specifically mention that incandescents will be banned, but that is the effect of the law. Now whether the federal government actually has the authority to regulate lighting efficiency standards is a different matter, it is possible the Supreme Court may restrict the enforcement of the law if it feels the federal government is overstretching the authority granted to it through the commerce clause in the Constitution. But most stores and factories are not going to want to risk legal trouble.

Bold emphasis added. So you admit, it does not ban incandescent bulbs. I'm tired of people falsely claiming that the law does this.

Correct, my mistake. Perhaps the figure is 1.7 kiloJoules ? That would be the equivalent of 1000 hours of use.

Manufacturers usually claim that their CFL's have a lifetime of 5000 hours, but this is often a lie. Many of the cheaper CFL's have a lifetimes as low has 2500 hours. I am surprised there has not been any class action lawsuits against these companies yet. Many of these companies are using inferior electronic parts that cause the bulb to fail early, not just because it is cheaper, but also because they can sell more bulbs that way. Remember, all these bulbs are made in Chinese factories, and we all know Chinese companies have much lower ethical standards.

One source I found stated that producing a compact fluorescent bulb consumes about five times as much energy as it takes to make an incandescent bulb.

Oooh, five times. That's a lot. But that's per bulb, and since this is not a 1-for-1 replacement, that's not exactly an honest comparison.

A typical CFL lasts ~5x longer than a typical traditional incandescent (numbers vary somewhat depending on the source; some put it at more than 10), so the actual energy to produce a set amount of lighting is about the same. 1/5 x 5 = 1. So production energy is a wash, and you're left with the lower operating costs. Which, BTW, are a lot more than the cost of the bulb. 1000 hours for a 100W bulb is 100 kWh. At $0.10 per kWh, that's$10 to operate a traditional bulb. Much, much more than the cost of the bulb.

Here is one comment made by James Rhyner at St. Cloud University:

"I have been trying CFL's for several years and have yet to have one that lasts longer than an incandescent bulb. Again the politicians are trying to run our lives. As another writer mentions, the costs of producing and disposing of the CFL's are probably much greater than the operating and disposal costs of incandescents. Of course no one wants to analyze that as the politicians will lose their kick backs from the Chinese manufacturers (I despise congress and don't trust them)"

(December 15, 2011)

Wow, an anecdote that also has a conspiracy angle. I've used CFLs for years and haven't had to replace them at nearly the rate I would replace incandescents. So there.

And "probably much greater"? Are you quoting a math-o-phobe? Why do you have to guess when you can do the analysis?

Real-world reports from the home front show that the claimed extended lifespan of CFLs is often greatly exaggerated. There is ample data indicating that the frequent switching on and off of CFLs greatly shortens their life. A study by H. Sterling Burnett, senior fellow at the National Center for Policy Analysis, and co-author Amanda Berg concludes:

“Unfortunately, except under a fairly narrow range of circumstances, CFLs are less efficient than advertised. Manufacturers claim the average life span of a CFL bulb is 10,000 hours. However, in many applications the life and energy savings of a CFL are significantly lower. Applications in which lighting is used only briefly (such as closets, bathrooms, motion detectors and so forth) will cause CFL bulbs to burn out as quickly as regular incandescent bulbs . . . When initially switched on, CFLs may provide as little as 50 percent to 80 percent of their rated light output and can take up to three minutes to reach full brightness.”

http://www.ncpa.org/pub/ba637/

This is a known issue with CFLs. You know what the solution is? Don't use them in these situations.

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I can only assume you are using a definition of essentially that means "not, but I don't have an actual, factual counterargument". You are shifting the goalposts from "incandescents" to "regular incandescents" and back when it suits you. Incandescent bulbs are not being banned. This is not a lie.

I wasn't talking about the "normal" ones, which are very inefficient. See the above objection to moving the goalposts.

Bold emphasis added. So you admit, it does not ban incandescent bulbs. I'm tired of people falsely claiming that the law does this.

Oooh, five times. That's a lot. But that's per bulb, and since this is not a 1-for-1 replacement, that's not exactly an honest comparison.

A typical CFL lasts ~5x longer than a typical traditional incandescent (numbers vary somewhat depending on the source; some put it at more than 10), so the actual energy to produce a set amount of lighting is about the same. 1/5 x 5 = 1. So production energy is a wash, and you're left with the lower operating costs. Which, BTW, are a lot more than the cost of the bulb. 1000 hours for a 100W bulb is 100 kWh. At $0.10 per kWh, that's$10 to operate a traditional bulb. Much, much more than the cost of the bulb.

Wow, an anecdote that also has a conspiracy angle. I've used CFLs for years and haven't had to replace them at nearly the rate I would replace incandescents. So there.

And "probably much greater"? Are you quoting a math-o-phobe? Why do you have to guess when you can do the analysis?

This is a known issue with CFLs. You know what the solution is? Don't use them in these situations.

Now that the math is all figured out, the only question I have is: How do we sell these new CFLs to the poor who doesn't have money to purchase them?
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The law basically has the effect of banning normal light bulbs, for all practical purposes. Surely you are not disagreeing with that?

I am not aware of the existence of any "higher-efficiency" incandescent light bulbs that will be allowed under the law. If you know where I can buy incandescent bulbs with an efficiency over 45 lumens/Watt, please tell us all where to find them.

As for those "other options" you claim, what exactly are they? I certainly do not think it is realistic to expect normal people to swith over to LED lighting. It is just too expensive. Sure you can buy an LED night light for a few dollars, but how bright is it? Not bright enough for much. Please, if you feel I am mistaken, tell us all where we buy an affordable LED bulb that puts out the equivalent light of a 100 Watt incandescent (by affordable, I mean under 70 dollars for 1 bulb)

And what other lighting option do we have? Candles? Kerosene lamps?

No, for those of us who do not have stockpiles of the old bulbs, the only other practical option is buying those wretched CFL's.

Stop getting into technicalities. It is a ban! It seems obvious to me that you are one of the people in favor of the law, and want to force CFL's onto everyone else, whether they like it or not.

You would not be the first. There are plenty of other lies and misleading claims that have appeared in the media and even on government sites. People were even going around on the internet saying that it was all just a false rumor, that Americans would still be able to buy incandescent bulbs. After the 100 Watt bulbs dissappeared from store shelves in the first phase in the law, the nazi-environmentalists claimed normal incandescents would be banned, but halogen bulbs would still be available. Now the 70 Watt bulbs have dissappeared, and those halogen bulbs we were promised are nowhere to be found (except for the very dim ones, which will soon also be banned).

Edited by Anders Hoveland
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The law basically has the effect of banning normal light bulbs, for all practical purposes. Surely you are not disagreeing with that?

Fine, I will repeat myself. Again. What you are referring to as "normal" light bulbs will not meet the efficiency standards. That's not the same as saying incandescent light bulbs are being banned. There are higher-efficency bulbs which are incandescent. Incandescent bulbs are available, thus they are not being banned.

I am not aware of the existence of any "higher-efficiency" incandescent light bulbs that will be allowed under the law. If you know where I can buy incandescent bulbs with an efficiency over 45 lumens/Watt, please tell us all where to find them.

Argument from personal incredulity and refusal to use a search engine is not much of an argument.

http://www.bulbs.com/espec.aspx?ID=18362&RefId=750

Energy Independence and Security Act of 2007 Compliant

Note that your demand of compliance with the law and 45 lumens/Watt are different. 45 lumens/Watt is NOT the law in effect today, that's the standard to be implemented 8 years from now. I refer you to the objection of moving the goalposts I made in my previous post.

As for those "other options" you claim, what exactly are they? I certainly do not think it is realistic to expect normal people to swith over to LED lighting. It is just too expensive. Sure you can buy an LED night light for a few dollars, but how bright is it? Not bright enough for much. Please, if you feel I am mistaken, tell us all where we buy an affordable LED bulb that puts out the equivalent light of a 100 Watt incandescent (by affordable, I mean under 70 dollars for 1 bulb)

And what other lighting option do we have? Candles? Kerosene lamps?

No, for those of us who do not have stockpiles of the old bulbs, the only other practical option is buying those wretched CFL's.

The other option is the incandescent bulbs I have linked to, your claims of nonexistence notwithstanding.

Stop getting into technicalities. It is a ban! It seems obvious to me that you are one of the people in favor of the law, and want to force CFL's onto everyone else, whether they like it or not.

Again, I refer you to the link selling incandescent bulbs that meet the current standards.

You would not be the first. There are plenty of other lies and misleading claims that have appeared in the media and even on government sites. People were even going around on the internet saying that it was all just a false rumor, that Americans would still be able to buy incandescent bulbs. After the 100 Watt bulbs dissappeared from store shelves in the first phase in the law, the nazi-environmentalists claimed normal incandescents would be banned, but halogen bulbs would still be available. Now the 70 Watt bulbs have dissappeared, and those halogen bulbs we were promised are nowhere to be found (except for the very dim ones, which will soon also be banned).

The word "lie" is used quite cavalierly, given the amount of misinformation in your posts.

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The murky politics of the lightbulb ban, how lobbyists seek to increase corporate profits:

http://www.ceolas.net/

blog on why CFL's are not as good as the claims, and why consumers deserve the freedom to choose:

http://freedomlightbulb.blogspot.com/

Even in many offices, we are seeing employees turn off the fluorescent ceiling lights and bring in incandescent lamps. Obviously some people are very unhappy with the quality of fluorescent light.

There are higher-efficency bulbs which are incandescent. Incandescent bulbs are available, thus they are not being banned.

No, there are no "higher-efficiency" incandescent bulbs that will be available. They are essentially being banned. Like I mentioned, you have failed show that these alleged bulbs even exist, much less where we can buy them.

Here is an exerpt from the above link:

The "Similar bulbs will still be allowed" deceit

Consumers are deceived in many ways with the light bulb policy they are told will be so good for them. However, one should particularly note the main defence tactic that will be employed by American politicians and agencies, exactly like in Europe and Australia, when the governments there were faced with concerned citizens...

"We don't wan't to have to use the dim unsafe mercury-containing squiggly bulbs with their unnatural light!"

"Don't worry! Energy efficient incandescent light bulbs, similar to ordinary incandescent light bulbs, will still be allowed!"

To begin with,

Replacement Halogens have a whiter light type and like all replacement incandescents have constructional differences with simple regular bulbs, apart from costing much more for relatively small energy savings, which is why neither consumers or governments like them, since they have been around for a while now without being sold much.

Thereby that in the USA, as in the EU, all currently known incandescent replacement bulbs, Halogen or otherwise, will only temporarily be allowed - as in the regulation references above. [see in the site]

Only if they become as energy efficient as CFLs and LEDs would they be allowed:

Not just unlikely, but if it did occur, it would involve constructional compromise and cost that made them even more different from simple regular bulbs - notwithstanding that any such lighting, like all lighting, would of course have its own advantage too.

Moreover, in post-ban 2011 Europe (as in UK, Ireland, Scandinavia, Germany and Italy) and Australia, replacement energy efficient incandescents are only available in limited replacement range, regarding sizes and wattages compared to the pre-ban range of simple regular cheap bulbs.

Also, they are hardly available in general stores and supermarkets, which push CFL sales:

Replacement Halogen types are usually only available in specialist shops, and since LEDS are unsuitable as replacements for regular bulbs (too high a price, especially for omni-directional bright replacements), what is seen in supermarkets and general stores is not just the almost sole availability of CFLs, but also the in-store enticement to buy them, marketed as as "saving consumers a lot of money".

Replacement incandescents, like Halogens, will also be banned in the USA and EU.

Post-ban EU already lacks touted Halogen availability, CFL retail sales being pushed.

Edited by Anders Hoveland
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I have to admit I've had a lot of problems with CFLs, I replace them at a rate not any better than incandescents. The new house I moved into eats CFLs, they are expensive to replace that often.

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No, there are no "higher-efficiency" incandescent bulbs that will be available.

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The new house I moved into eats CFLs, they are expensive to replace that often.

They tend to be more sensitive to poor wiring and dimmer switches. What's the wiring like in your home? Is there too much load on each breaker?

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They tend to be more sensitive to poor wiring and dimmer switches. What's the wiring like in your home? Is there too much load on each breaker?

You could have a point, the house is very old, 80 years or so and the wiring is hodge podge of various eras.

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!

Moderator Note

Anders,

This is becoming a case of soap boxing. You have made your points, which members here have refuted and you seem to have completely ignored. You cannot possibly claim that those bulbs cannot be purchased, when swansont posted you a link to a site that sells them. Please start engaging in honest discussion or this thread will be closed.

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!

Moderator Note

Anders,

This is becoming a case of soap boxing. You have made your points, which members here have refuted and you seem to have completely ignored. You cannot possibly claim that those bulbs cannot be purchased, when swansont posted you a link to a site that sells them. Please start engaging in honest discussion or this thread will be closed.

No argument with their application and possible savings, but at those prices; how is an indigent supposed to purchase them? Edited by rigney
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Seriously, how much more are they than incandescents?

Let's say you pay $0.50 for an incandescent. It will last 1,000 hours Instead, you pay$3.00 for a fluorescent that lasts 10,000 hours

You have to buy 10 incandescent bulbs to match one fluorescent, so it will actually cost you $5.00. In short... Mr. "I'm poor and indigent, and just an ole' mountain slob... oh woe is me," the more efficient bulb is saving you money on your electric bill AND at the store. Edit for link: http://www.ajdesigner.com/fl_light_bulb/light_bulb.php Edited by iNow ##### Link to comment ##### Share on other sites No argument with their application and possible savings, but at those prices; how is an indigent supposed to purchase them? ...Wut? ##### Link to comment ##### Share on other sites Seriously, how much more are they than incandescents? Let's say you pay$0.50 for an incandescent. It will last 1,000 hours

Instead, you pay $3.00 for a fluorescent that lasts 10,000 hours You have to buy 10 incandescent bulbs to match one fluorescent, so it will actually cost you$5.00.

In short... Mr. "I'm poor and indigent, and just an ole' mountain slob... oh woe is me," the more efficient bulb is saving you money on your electric bill AND at the store.

Evidently neither you nor I have the problem of saving a buck. But only an idiot would think there aren't people out there who doesn't have that extra buck.
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Evidently neither you nor I have the problem of saving a buck. But only an idiot would think there aren't people out there who doesn't have that extra buck.

I am going to go with rigney on this one, I have in recent years been in that boat where \$1 made a big difference in my life, deciding to buy a fancy light bulb or buy a cheap one and eat... I generally choose eating... as far as my electric bill goes I see no discernible difference... then again I live near a nuclear power plant, power plants both nuclear and coal fired are scattered around the area and electricity is cheap...

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And, as I showed, the CFLs will save you two bucks...

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No argument with their application and possible savings, but at those prices; how is an indigent supposed to purchase them?

I think that discussion of government aid programs (and possibly electing officials who won't gut them) is another topic.

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And, as I showed, the CFLs will save you two bucks...

Right! But a drowning man grasping at straws can't possibly envision looking at your bail of hay.

I think that discussion of government aid programs (and possibly electing officials who won't gut them) is another topic.

I simply offered an observation, the government and aid program remarks must have came from someone else. Edited by rigney

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text:
## Don't Call Us, We'll Call You

#### Saturday, January 7, 2017 · 3 min read

Look. I get it. Monad tutorials are a meme, memes about monad tutorials are a meme, and we’re almost at the point where memes about memes about monad tutorials are a meme. Before we go any farther down this infinite stack of turtles, though, I want to share one way to think about monads that doesn’t involve burritos or boxes or any Haskell code at all. I present to you, the Sugarloaf Transformation.

The overall idea makes sense to me because I’m a fan of visual metaphors. Your mileage may vary.

Consider the dataflow programming paradigm (think of Quartz Composer or LabView-G). A dataflow language takes the idea of an abstract syntax tree and extends it to the tree’s close relative, the directed acyclic graph. A dataflow program is a DAG where the edges entering and leaving each node are ordered. Each edge is associated with a value, and a node computes the values of its out-edges based on the values of its in-edges. Nodes with no in-edges are called sources, and nodes with no out-edges are called sinks. The program below computes the difference between 3 and 1, and prints the number 2. The two nodes on the left are sources that return constants; the print node is a sink.

+---+
| 3 |--+
+---+  |   +-------+
+-->|       |   +-------+
| minus |-->| print |
+-->|       |   +-------+
+---+  |   +-------+
| 1 |--+
+---+

To interpret a dataflow program, we have a variety of strategies. We could begin at sinks and recursively descend into in-edges until we reach sources, which can be evaluated with no further work. This corresponds to a recursive-descent interpreter of an AST. Alternatively, we could begin by collecting the set of sources, evaluating them, assigning the results to the respective out-edges. Then, we iteratively find and evaluate nodes whose in-edges have all been assigned values, until at last we have evaluated the entire program.

The point I wish to make is that the order in which nodes are evaluated is nondeterministic. Thus, the following “obvious” program to subtract two numbers is not well-defined. If given inputs “3, 1” by a human, it may output “2” or “-2” depending on the order in which the two read nodes were evaluated.

+------+
+------+  |   +-------+
+-->|       |   +-------+
| minus |-->| print |
+-->|       |   +-------+
+------+  |   +-------+
+------+

The problem is that nondeterministic evaluation order for IO results in the evaluator potentially diverging. This is really bad! How can we force a deterministic order of execution for IO primitives? Well, notice that the only way to force node x to evaluate before node y is to make y depend on the output of x. We can have each node output an “ordering sentinel” that becomes the input to future nodes: this allows us to impose a partial ordering on node evaluation, as shown below.

+-------+   +------+     +------+
| start |-->|      |---->|      |
|      |-+   |      |-+
+------+ |   +------+ |
|            |   +-------+
|            +-->|       |   +-------+
|                | minus |-->| print |
+--------------->|       |   +-------+
+-------+

The start node simply emits an ordering sentinel, to kick off the computation.

This looks really good: this program is, in fact, well-defined in its execution order. Sadly, a partial ordering still allows divergent programs. Why? It’s because, in the words of Philip Wadler, “Truth is free.” Once you have computed a sentinel, you can use it wherever you want. What prevents us from doing this?

               +------+
+-->|      |
|   |      |----->|       |   +-------+
+-------+  |   +------+      | minus |-->| print |
| start |--+             +-->|       |   +-------+
+-------+  |   +------+  |   +-------+
+-->|      |  |
|      |--+
+------+

Nothing. Yikes.

If the problem is that “truth is free,” we might be able to solve the problem by simply restricting the flow of information created by IO primitives. One solution is to sandbox all computation that uses the output of an IO node. An easy way to do this is to “lock” the output of an IO node in a special pipe that can only be unlocked by entering a sandbox. Of course, sandboxes must only allow locked values to exit—otherwise you can trivially pass a value through the null sandbox to unlock it. Our program then becomes the following (the dotted boxes denote sandboxes, and fat arrows are locked).

            .................................................
+------+    :                                               :
+------+    :               |                               :
:             ..|............................   :
:             : |                           :   :
:             : |   +-------+               :   :
:             : +-->|       |   +-------+   :==>:==> ...
: +------+    :     | minus |-->| print |==>:   :
: | read |===>@---->|       |   +-------+   :   :
: +------+    :     +-------+               :   :
:             :                             :   :
:             :.............................:   :
:                                               :
:...............................................:

Notice that since a sandbox only unlocks one pipe at a time, and does not allow the unlocked value to escape, our previous divergence hack becomes impossible. minus takes two unlocked inputs, so they must be computed in nested sandboxes which ensure sequential execution. Indeed, by generalizing, it is not hard to see that now there is only one way to compute the contents of a locked pipe. This means that the result of a locked pipe is literally the same as the computation that goes into evaluating its contents—and so our programs must have a well-defined execution order.

In Haskell, locked pipes correspond to values “boxed” in a value of type IO a (this is where the burrito metaphor stems from). Sandboxes are lambdas, and the unlocking mechanism @ is the monadic binding operator >>=. The return function in Haskell is simply a node that locks its input—this lets us return an arbitrary value from a sandbox. Finally, do-notation is just syntactic sugar to save programmers from reasoning about lots of nested sandboxes, in the same spirit that C has in letting you write 1+2+3+4 instead of 1+(2+(3+4)).

P.S. The title of this post refers to the idea that this transformation in a way inverts the traditional flow of control. Normally, minus would call read twice to get the values of its inputs. Here, however, the reads are calling minus to create their output. “Don’t call us, we’ll call you.”

◊ ◊ ◊

format: plain


text:
# Probability computation involving order statistics

Let $X_1$, $X_2$.. $X_n$ be iid uniform random variables i.e. $X_i \sim U(0,1)$. We know that the order statistics, $X_{(i)}$ is beta distributed $X_{(k)} \sim B(k,n+1-k)$.

Also let $Y_1$, $Y_2$.. $Y_n$ be another set of uniform random variables i.e. $Y_i \sim U(0,1)$. The order statistics $Y_{(i)}$ are also beta distributed $Y_{(k)} \sim B(k,n+1-k)$.

I'm interested in finding the following probability,

$\Pr(X_{(1)} < Y_{(2)}, X_{(2)} < Y_{(3)})= ?$

The problem here is that the events $E_1 \equiv \{X_{(1)} < Y_{(2)}\}$ and $E_2 \equiv \{X_{(2)} < Y_{(3)}\}$ etc are not independent, and I'm unable to come up with ways to make them independent so as to make use of the known marginal densities.

Is there any simple way to solve this problem? Any pointers to a solution are welcome.

-
Using Mathematica, one can find the answer using Probability[ x1 < y2 && x2 < y3, {Distributed[{x1,x2}, OrderDistribution[{UniformDistribution[],n}, {1, 2}]], Distributed[{y2,y3}, OrderDistribution[{UniformDistribution[], n}, {2, 3}]]}] that gives the answer of $$\Pr\left(X_{(1)} < Y_{(2)}, X_{(2)} < Y_{(3)}\right) = \frac{(5n-4)(n-1)-1}{8(n-1)^2 - 2}$$ –  Sasha Mar 18 '13 at 17:04
In Mathematica, is it possible to use an arrays x[1] and y[2], instead of x1,x2 and y1,y2? It will help to get the general result when an expression such as $\Pr\left(X_{(1)} < Y_{(2)}, X_{(2)} < Y_{(3)},.., X_{(k)} < Y_{(m)}\right)$ need to be evaluated. How else can this be solved for a variable k? –  AIB Apr 13 '13 at 1:27
Yes, it is possible. Direct substitution just works: Probability[ x[1] < y[2] && x[2] < y[3], {Distributed[{x[1], x[2]}, OrderDistribution[{UniformDistribution[], n}, {1, 2}]], Distributed[{y[2], y[3]}, OrderDistribution[{UniformDistribution[], n}, {2, 3}]]}] –  Sasha Apr 13 '13 at 2:22

One solution is to use joint distribution for two order statistics: $$f_{X_{1:n}, X_{2:n}}\left(x_1, x_2\right) = n(n-1) \left(1-x_2\right)^{n-2} \left[ 0 < x_1 < x_2 <1\right]$$ $$f_{Y_{2:n}, Y_{3:n}}\left(y_2, y_3\right) = n(n-1)(n-2) y_2 \left(1-y_3\right)^{n-3} \left[ 0 < y_2 < y_3 <1\right]$$ To evaluate the probability use $$\begin{eqnarray} \Pr\left(X_{1:n}\lt Y_{2:n},X_{2:n}\lt Y_{3:n}\right) &=& \mathbb{E}\left( \Pr\left(X_{1:n}\lt Y_{2:n},X_{2:n}\lt Y_{3:n} \mid Y_{2:n},Y_{3:n}\right) \right) \\ &=& \mathbb{E}\left( F_{X_{1:n},X_{2:n}}\left(Y_{2:n},Y_{3:n}\right)\right) \end{eqnarray}$$ The probability $F_{X_{1:n},X_{2:n}}(y_2,y_3)$ is computed as follows, assuming $0<y_2<y_3<1$ $$\begin{eqnarray} F_{X_{1:n},X_{2:n}}(y_2,y_3) &=& n(n-1) \int_0^{y_3} \mathrm{d}x_2 \int_{0}^{\min(y_2,x_1)} \mathrm{d}x_1 \cdot \left(1-x_2\right)^{n-2} \\&=& 1 - \left(1-y_2\right)^{n} - n y_2 \left(1-y_3\right)^{n-1} \end{eqnarray}$$ Now $$\begin{eqnarray} \Pr\left(X_{1:n}\lt Y_{2:n},X_{2:n}\lt Y_{3:n}\right) &=& 1 - \mathbb{E}\left( \left(1-Y_{2:n}\right)^{n} \right) - n \mathbb{E}\left( Y_{2:n} \left(1-Y_{3:n}\right)^{n-1}\right) \\ &=& 1 - \mathbb{E}\left( Y_{n-1:n}^{n} \right) - n \mathbb{E}\left( Y_{2:n} \left(1-Y_{3:n}\right)^{n-1}\right) \end{eqnarray}$$ The latter integral is easy to evaluate: $$\begin{eqnarray} n \mathbb{E}\left( Y_{2:n} \left(1-Y_{3:n}\right)^{n-1}\right) &=& \int_0^{1} \mathrm{d}y_3 \int_0^{y_3} \mathrm{d} y_2 \cdot n^2(n-1)(n-2) y_2^2 (1-y_3)^{2n-4} \\ &=& \frac{n^2 (n-1)(n-2)}{ \frac{1}{2} (2n)(2n-1)(2n-2)(2n-3)} \int_0^{1} \mathrm{d}y_3 \int_0^{y_3} f_{Z_{3:2n},Z_{4:2n}}\left(y_2,y_3\right) \\ &=& \frac{n(n-2)}{2 (2n-1)(2n-3)} \end{eqnarray}$$ The remaining integral is evaluated using singe statistics density function: $$\mathbb{E}\left( Y_{n-1:n}^{n} \right) = \int_0^1 x^n \cdot n(n-1) x^{n-2} (1-x) \mathrm{d} x = \frac{n(n-1)}{2n(2n-1)} \int_0^1 f_{Y_{2n-1:2n}}(x) \mathrm{d}x = \frac{n-1}{2(2n-1)}$$ Thus $$\Pr\left(X_{1:n}\lt Y_{2:n},X_{2:n}\lt Y_{3:n}\right) = 1-\frac{n-1}{2(2n-1)}-\frac{n(n-2)}{2 (2n-1)(2n-3)}=\frac{(5n-4)(n-1)-1}{2(2n-1)(2n-3)}$$
Thanks a ton!! One more thing, is there a general formula for the joint distribution of k order statistics i.e. $f_{X_{1:n}, X_{2:n} ...X_{k:n}}\left(x_1, x_2, ..., x_k\right)$ , for uniform density? –  AIB Mar 18 '13 at 20:14
@AIB Yes, it reads $$f_{X_{1:n},X_{2:n},\ldots,X_{k:n}}\left(x_1,x_2,\ldots,x_k\right) = \frac{n!}{(n-k)!} (1-x_k)^{n-k} [ 0<x_1<x_2<\ldots<x_k<1]$$ It is easily obtained as a marginal density of the complete order statistics pdf: $$f_{X_{1:n},X_{2:n},\ldots,X_{n:n}}\left(x_1,x_2,\ldots,x_n\right) = n! [ 0 < x_1 < x_2 < \cdots < x_n < 1]$$ There are some good books on order statistics, like this and that. –  Sasha Mar 18 '13 at 20:36
@AIB Do you mean the cdf of all order statistics, i.e. $$\Pr\left(X_{1:n} \leqslant x_1, X_{2:n} \leqslant x_2, \ldots, X_{n:n} \leqslant x_n \right)$$ There is an expression for it in terms of multiple sum that involves products of $F_X$ Look at the page 18 of the first book for the logic of deriving it. –  Sasha Mar 20 '13 at 18:37
Actually, I meant $\Pr\left(X_{1:n} \leqslant x_1, X_{2:n} \leqslant x_2, \ldots, X_{k:n} \leqslant x_k \right)$. This (marginal), I think, can be obtained by setting $x_{k+1}=1,x_{k+2}=1,...x_n=1$ in the cdf of all order statistics. Meanwhile, I am trying to a get a copy of the book from our library. –  AIB Mar 23 '13 at 7:28


text:
## Elementary Technical Mathematics

$18$ kilometers.
The SI unit for the abbreviation $18 \ km$ is $18$ kilometers.


text:
Definitions

# Renal clearance ratio

The renal clearance ratio or fractional excretion is a measure of the speed at which a constituent of urine passes through the kidneys. It is defined by following equation:

$clearance ratio of X = frac\left\{C_x\right\}\left\{C_\left\{in\right\}\right\}$

Creatinine is sometimes used instead of inulin as the reference substance.

Search another word or see renal clearanceon Dictionary | Thesaurus |Spanish


text:
Can I use rtracklayer to get the sequence surrounding a set of variants?
2
0
Entering edit mode
@stephanie-m-gogarten-5121
Last seen 8 weeks ago
University of Washington

I have a set of variants stored in a GRanges, and I'd like to get the surrounding reference sequence (+/- 100 bp) for each one. I can use rtracklayer to view the variants in UCSC, and I can then get the surrounding sequence by going to the table browser, selecting my custom track and "output format: sequence", then specifying the number of extra bases I want in the browser window. Is there a way to do this programmatically from within R?

rtracklayer sequencing reference genome • 824 views
1
Entering edit mode
@stephanie-m-gogarten-5121
Last seen 8 weeks ago
University of Washington

No reason, I just hadn't used it before. Turns out it's super easy. Solution for posterity:

> library(BSgenome.Hsapiens.UCSC.hg19)
> gr <- GRanges("chr1", IRanges(65500, 65500))
> start(gr) <- start(gr) - 100
> end(gr) <- end(gr) + 100
> getSeq(Hsapiens, gr, as.character=TRUE)
[1] "AAAGCTCAGACTGGCTATTCCCAGATCTCTTCAGGTACATCTAGTCCATTCATAAAGGGCTTTTAATTAACCAAGTGGTTTACTAAAAAGGACAATTCACTACATATTATTCTCTTACAGTTTTTATGCCTCATTCTGTGAAAATTGCTGTAGTCTCTTCCAGTTATGAAGAAGGTAGGTGGAAACAAAGACAAAACACAT"
0
Entering edit mode
@michael-lawrence-3846
Last seen 5 months ago
United States

Currently, no. There was some work on that, but it was abandoned, I think because BSgenome already offers the sequence for the important organisms. Is there some reason why you can't use a BSgenome package?


text:
## Fundamentals of Physics Extended (10th Edition)

Published by Wiley

# Chapter 2 - Motion Along a Straight Line - Problems: 18b

velocity = 48m/s

#### Work Step by Step

The position is given by $x = 12t^2 - 2t^3$ Since the velocity equation is the derivative of the position equation we need to find $\frac{d}{dt} (12t^2 - 2t^3)$ Since $\frac{d}{dt} t^n = n*t^(n-1)$ then $\frac{d}{dt} (12t^2 - 2t^3) = 12(2)t - 2(3)t^2 = 24t - 6t^2$ To find the velocity at t =3, we need to plug this into the velocity equation This gives us $24(3) - 6(2)^2 = 72 - 24 = 48m/s$

After you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.


text:
Infoscience

Conference paper

# Solving a $6120$-bit DLP on a Desktop Computer

In this paper we show how some recent ideas regarding the discrete logarithm problem (DLP) in finite fields of small characteristic may be applied to compute logarithms in some very large fields extremely efficiently. By combining the polynomial time relation generation from the authors’ CRYPTO 2013 paper, an improved degree two elimination technique, and an analogue of Joux’s recent small-degree elimination method, we solved a DLP in the record-sized finite field of $2^{6120}$ elements, using just a single core-month. Relative to the previous record set by Joux in the field of $2^{4080}$ elements, this represents a 50% increase in the bitlength, using just 5% of the core-hours. We also show that for the fields considered, the parameters for Joux’s $L_Q(1/4+o(1))$ algorithm may be optimised to produce an $L_Q(1/4)$ algorithm.

#### Reference

• EPFL-CONF-215122

Record created on 2016-01-19, modified on 2016-08-09


text:
## Finding rocket's distance at various angles after launch

Trigonometric ratios and functions, the unit circle, inverse trig functions, identities, trig graphs, etc.
JDC
Posts: 15
Joined: Mon Nov 25, 2013 2:46 am
Contact:

### Re: Finding rocket's distance at various angles after launch

JDC
Posts: 15
Joined: Mon Nov 25, 2013 2:46 am
Contact:

### Re: Finding rocket's distance at various angles after launch

Does this sound right so far?

tan(45)=1
150*1=150

tan(10) = .176327
150*.176327 = 26.44905

150-26.44905 = 123.551

am I even close?

buddy
Posts: 197
Joined: Sun Feb 22, 2009 10:05 pm
Contact:

### Re: Finding rocket's distance at various angles after launch

why not use a calculator or a spreadsheet instead of a trig table?
tan(45)=1
150*1=150
what is the 150 coming from? are you doing something different than what you did at the starting?
tan(10) = .176327
150*.176327 = 26.44905
150-26.44905 = 123.551
am I even close?
i dont understand this at all. i showed you the regular trig way to do this:

Code: Select all

rocket path: l *. v a / |  . i u / |  . e n / |h  . w c /45* | 10*  . e h *---------*------------------* r |<===========150============>|
Since the triangle on the launch side is 45 degrees then the base is h too. Then the base of the viewer's triangle is 150-h.
so do like i said:

Code: Select all

triangle for A: l A*. v a / |  . i u / |  . e n / |h  . w c /45* | 10*  . e h *---------*------------------* r | h | 150-h | |<===========150============>|
So do the tangent of the 10 degrees & make it equal to h/(150-h).
so thats tan(10*)=h/(150-h)
(i don't know what 150*.176327 = 26.44905 is?)
solve tan(10*)=h/(150-h) for h.

JDC
Posts: 15
Joined: Mon Nov 25, 2013 2:46 am
Contact:

### Re: Finding rocket's distance at various angles after launch

Ok, when I use excel for TAN(10) I get 0.176327

So, if you're saying that "h/(150-h)" needs to equal the same then I'm not sure how to formulate that.

I don't know the formula, but, by deduction it's about "22.4845"

How do I get 22.5?

JDC
Posts: 15
Joined: Mon Nov 25, 2013 2:46 am
Contact:

### Re: Finding rocket's distance at various angles after launch

Ok, I figured it out finally!

I just created a SpreadSheet and found all the formulas 1 at a time...

Thanks for helping, I think you might have left out a critical piece re:SinA, once I read about that it all made sense

In the spreadsheet, it only requires A, B and c

nona.m.nona
Posts: 288
Joined: Sun Dec 14, 2008 11:07 pm
Contact:

### Re: Finding rocket's distance at various angles after launch

No information was omitted from the step-by-step solution method provided to you earlier. Rather, you elected to solve in a completely different manner. As a result, you used different steps.

Thank you for posting your solution method for the benefit of other viewers. As is so often the case, your exercise admitted of more than one valid solution method.

JDC
Posts: 15
Joined: Mon Nov 25, 2013 2:46 am
Contact:

### Re: Finding rocket's distance at various angles after launch

Is there a quicker way of doing this?

Sorry, but, I could not understand the solution you tried to walk me through, would you mind posting something similar?

If there is an easier way I'd like to know, the above steps seemed to be a little overkill, but, at least I was able to get the answer.

I did translate this into C# code if anyone is interested....

public class Collision
{
public double X1; //Left Side
public double X2; //Right Side
}

public Collision GetCollisionPoint(int baseWidth, double angleA, double angleB)
{
int c = baseWidth;
double sinA = Sin(angleA);
double sinB = Sin(angleB);
double sinC = Sin(180 - angleA - angleB);
double tanB = Tan(angleB);
double a = c*sinA/sinC;
double height = a*sinB;
double length = height/tanB;

return new Collision {X1 = baseWidth - length, X2 = length};
}

public double Sin(double value)
{
return Math.Sin(Degrees(value));
}

public double ArcTan(double value)
{
return Math.Atan(Degrees(value));
}

public double Tan(double value)
{
return Math.Tan(Degrees(value));
}

private double Degrees(double value)
{
return value * Math.PI / 180;
}

JDC
Posts: 15
Joined: Mon Nov 25, 2013 2:46 am
Contact:

### Re: Finding rocket's distance at various angles after launch

Is there anyway to post zip files, I'd be happy to share the Excel SpreadSheet. If anyone else runs into this questions I'm sure it would be useful.

JDC
Posts: 15
Joined: Mon Nov 25, 2013 2:46 am
Contact:

### Re: Finding rocket's distance at various angles after launch

There is just 1, but, 3 different formats in case someone doesn't have Excel. There is open document format as well, Open Office is free.

Hope someone finds this useful.

nona.m.nona
Posts: 288
Joined: Sun Dec 14, 2008 11:07 pm
Contact:

### Re: Finding rocket's distance at various angles after launch

Is there a quicker way of doing this?
Of doing which?
Sorry, but, I could not understand the solution you tried to walk me through, would you mind posting something similar?
Certainly. It is useful to begin with the coded "picture" as provided by the other poster:

Code: Select all

triangle for A: l A*. v a / |  . i u / |  . e n / |h  . w c /45* | 10*  . e h *---------*------------------* r | h | 150-h | |<===========150============>|
For a similar set-up, suppose that the distance between the "launch" location and the "viewer" location is "d", and that the angles are "L" and "V", respectively; let the distances be "x" and "y", respectively.

Code: Select all

triangle for A: l A*. v a / |  . i u / |  . e n / |h  . w c / L* | V*  . e h *---------*------------------* r | x | y | |<===========d==============>|
Then tan(L*) = h/x, so h = x tan(L*); tan(V*) = h/y, so h = y tan(V*). Noting that y = d - x, one obtains h = (d - x) tan(V*). Setting the two expressions for "h" equal (as h must necessarily equal itself), one obtains (d - x) tan(V*) = x tan(L*):

$(d\, -\, x)\tan(V^{\circ})\, =\, x\tan(L^{\circ})$

$d\tan(V^{\circ})\, -\, x\tan(V^{\circ})\, =\, x\tan(L^{\circ})$

$d\tan(V^{\circ})\, =\, x\left(\tan(V^{\circ})\, +\, \tan(L^{\circ})\right)$

$\displaystyle{\frac{d\tan(V^{\circ})}{\tan(V^{\circ})\, +\, \tan(L^{\circ})}\, =\, x$

As all values other than x are known, the solution follows.


text:
# MoUs

2020-08-13
09:08
 Memorandum of Understanding for the DsTau Collaboration - Participation of CERN CERN-MOU-2020-317.- Fulltext: PDF;

2020-08-10
16:50

2020-08-10
16:48

2020-08-10
16:45

2020-08-10
16:42

2020-08-10
16:34
 Addendum 14 to the Memorandum of Understanding for Collaboration in the Construction of the ATLAS Detector - Construction of the FTK Sub-System - Participation of KEK (JP) CERN-MOU-2020-316.- Fulltext: PDF;

2020-08-10
16:33
 Addendum 14 to the Memorandum of Understanding for Collaboration in the Construction of the ATLAS Detector - Construction of the FTK Sub-System - Participation of IN2P3-CNRS (FR) CERN-MOU-2020-315.- Fulltext: PDF;

2020-08-10
16:31
 Addendum 14 to the Memorandum of Understanding for Collaboration in the Construction of the ATLAS Detector - Construction of the FTK Sub-System - Participation of DESY (DE) CERN-MOU-2020-314.- Fulltext: PDF;

2020-08-10
16:30
 Addendum 14 to the Memorandum of Understanding for Collaboration in the Construction of the ATLAS Detector - Construction of the FTK Sub-System - Participation of BMBF (DE) CERN-MOU-2020-313.- Fulltext: PDF;

2020-08-10
16:28
 Addendum 14 to the Memorandum of Understanding for Collaboration in the Construction of the ATLAS Detector - Construction of the FTK Sub-System - Participation of INFN CERN-MOU-2020-312.- Fulltext: PDF;


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Now showing items 561-580 of 8484

• #### A three-dimensional finite element method for quantifying stress shielding following total hip replacement

(1993)
One of the critical problems associated with total hip replacement is the loosening of femoral stem. A major cause of femoral stem loosening is believed to be stress shielding of the proximal femur following implantation. ...
• #### A three-pulse algorithm for minimum-fuel rotational maneuvers

(2004)
Spacecraft equipped with a Reaction Control System (RCS) for attitude control typically utilize a "bang-off-bang" control algorithm for rotational maneuvers. This type of algorithm, which commands two distinct control ...
• #### A time series analysis of the Japanese yen

(1988)
This paper sought to address the question as to whether the exchange rate can be forecasted more accurately by a monetary model of exchange rate determination or the random walk in the case of the Japan-U.S. exchange ...
• #### A time series approach to quality control

(1991)
One way that a process may be said to be "out-of-control" is when a cyclical pattern exists in the observations over time. It is necessary that an accurate control chart be developed to signal when a cycle is present in ...
• #### A total synthesis of (+,-)-quinocarcin

(1988)
A synthetic route via the key intermediate DX-52-1 21 has resulted in the first total synthesis of the complex antitumor antibiotic quinocarcin 1. Salient features include an acyliminium ion-mediated stereoselective ...
• #### A transient methodology for evaluating risk reduction associated with ground water remediation at leaking underground storage tank sites

(1995)
A methodology to determine risk as a function of time varying concentration was developed and applied to three leaking underground storage tank sites for five remediation scenarios, to demonstrate the risk reduction ...
• #### A TRANSLATION AND STUDY OF THE "CHRONICON MONASTERII DE ABINGDON" (MONASTICISM, WOMEN, ENGLAND, JOSEPH STEVENSON)

(1986)
The Chronicon Monasteril de Abingdon, edited by the Reverend Joseph Stevenson, was first published in 1858 as part of the Rolls Series. The chronicle narrates the history of one of England's most distinguished monastic ...
• #### A triple approximation to the concept of aspect in Spanish

(1993)
The present analysis studies aspect from a triple perspective: morphological, semantic and syntactic. This division aims at clarifying the concept of aspect, accounting for the traditional dichotomy Imperfect/Preterit tense ...
• #### A TRUST REGION STRATEGY FOR NONLINEAR EQUALITY CONSTRAINED OPTIMIZATION (NONLINEAR PROGRAMMING, SEQUENTIAL QUADRATIC)

(1985)
Many current algorithms for nonlinear constrained optimization problems determine a search direction by solving a quadratic programming subproblem. The global convergence properties are addressed by using a line search ...
• #### A tunable hydrogel system and pulsatile flow bioreactor for the development of tissue engineered vascular grafts

(2009)
The prevalence of coronary artery disease combined with a paucity of suitable vessel substitutes act as driving forces for cardiovascular tissue engineering research. In this thesis poly(ethylene glycol) diacrylate (PEGDA) ...
• #### A tunable laser-based mid-infrared source for use in trace gas detection

(1997)
A new widely tunable mid-infrared (IR) source based on difference-frequency generation (DFG) in Gallium Selenide (GaSe) for use in high-resolution spectroscopy and trace gas detection is described. The characteristics of ...
• #### A two-dimensional model of the Venus ionosphere

(1988)
The Pioneer Venus observations show a peak in the O$\sb2\sp+$ concentration at $\sim$170 km altitude in the dayside ionosphere of Venus. In this thesis, the 2-dimensional MHD equations are solved in a self-consistent manner, ...
• #### A type-based prototype compiler for telescoping languages

(2009)
Scientists want to encode their applications in domain languages with high-level operators that reflect the way they conceptualize computations in their domains. Telescoping languages calls for automatically generating ...
• #### A TYPOLOGY OF WOMEN CHARACTERS IN THE GERMAN NATURALIST NOVEL

(1981)
The subject of this study is the image of woman in late 19th century German fiction. Upon examining a multitude of works produced within this time frame, it was found that the "naturalist" novel, in particular, provided a ...
• #### A unified approach to complex seismic imaging problems

(1991)
Two current challenges in seismic imaging are to obtain more detailed images of complex structures from reflection data and to constrain the regional structure of the Earth using wide-angle data. These are complex problems ...
• #### A unified approach to mitomycinoids: Application of a novel ene-like reaction

(1999)
A practical synthesis of the powerful antitumor agents, mitomycin C and FR900482, remains an elusive goal to this date. These substances may be thought to arise from suitably functionalized benzazocinones as retrosynthetic ...
• #### A union in disarray: Romanian nation building under Astra in late-nineteenth-century rural Transylvania and Hungary

(2002)
Scholarly studies of the nation as a socially constructed community, while accurate, do not explain how individuals in a predominantly agricultural society build and mobilize a national community outside of traditional ...
• #### A universal hidden Markov tree image model

(1999)
Wavelet-domain hidden Markov models have proven to be useful tools for statistical signal and image processing. The hidden Markov tree (HMT) model captures the key features of the joint density of the wavelet coefficients ...
• #### A Usability and Real World Perspective on Accessible Voting

(2012)
The HAVA (Help America Vote Act) mandated that all polling places provide privacy and independence to voters. DREs (Direct-Recording Electronic voting systems) have been assumed to be the solution to providing accessible ...
• #### A VARIABLE-METRIC VARIANT OF THE KARMARKAR ALGORITHM FOR LINEAR PROGRAMMING

(1987)
The most time-consuming part of the Karmarkar algorithm for linear programming is computation of the step direction, which requires the projection of a vector onto the nullspace of a matrix that changes at each iteration. ...


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DeepAI

Breaking The Dimension Dependence in Sparse Distribution Estimation under Communication Constraints

We consider the problem of estimating a d-dimensional s-sparse discrete distribution from its samples observed under a b-bit communication constraint. The best-known previous result on ℓ_2 estimation error for this problem is O( slog( d/s)/n2^b). Surprisingly, we show that when sample size n exceeds a minimum threshold n^*(s, d, b), we can achieve an ℓ_2 estimation error of O( s/n2^b). This implies that when n>n^*(s, d, b) the convergence rate does not depend on the ambient dimension d and is the same as knowing the support of the distribution beforehand. We next ask the question: “what is the minimum n^*(s, d, b) that allows dimension-free convergence?”. To upper bound n^*(s, d, b), we develop novel localization schemes to accurately and efficiently localize the unknown support. For the non-interactive setting, we show that n^*(s, d, b) = O( min( d^2log^2 d/2^b, s^4log^2 d/2^b) ). Moreover, we connect the problem with non-adaptive group testing and obtain a polynomial-time estimation scheme when n = Ω̃(s^4log^4 d/2^b). This group testing based scheme is adaptive to the sparsity parameter s, and hence can be applied without knowing it. For the interactive setting, we propose a novel tree-based estimation scheme and show that the minimum sample-size needed to achieve dimension-free convergence can be further reduced to n^*(s, d, b) = Õ( s^2log^2 d/2^b).

• 10 publications
• 34 publications
• 27 publications
10/07/2021

Pointwise Bounds for Distribution Estimation under Communication Constraints

We consider the problem of estimating a d-dimensional discrete distribut...
06/22/2022

List-Decodable Covariance Estimation

We give the first polynomial time algorithm for list-decodable covarianc...
01/10/2019

Mean Estimation from One-Bit Measurements

We consider the problem of estimating the mean of a symmetric log-concav...
09/22/2021

Sparse Uniformity Testing

In this paper we consider the uniformity testing problem for high-dimens...
02/12/2018

Some effects in adaptive robust estimation under sparsity

Adaptive estimation in the sparse mean model and in sparse regression ex...
02/23/2018

Geometric Lower Bounds for Distributed Parameter Estimation under Communication Constraints

We consider parameter estimation in distributed networks, where each nod...
01/29/2018

Temporally-Biased Sampling for Online Model Management

To maintain the accuracy of supervised learning models in the presence o...


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# zbMATH — the first resource for mathematics

On Lipschitz midconvex multifunctions. (English) Zbl 1103.26011
It is proved that a normed space-valued midconvex multifunction with non-empty closed and bounded values, weakly upper bounded on a suitable ball of a normed space $$X$$, is locally Lipschitzian. The proof utilizes some technical results, which are demonstrated in the first part of the paper. Moreover, as a corollary, a sufficient condition for Lipschitzianity of $$F$$ on the whole of $$X$$ is given.

##### MSC:
 26A51 Convexity of real functions in one variable, generalizations
##### Keywords:
multifunction; convexity; Lipschitz condition
Full Text:
##### References:
 [1] NIKODEM K.: K-convex and K-concave set-valued functions. Zeszyty Nauk. Politech. Łódz. Mat. 559 (1989), 1-75. [2] PSHENICHNYI B.: Convex multivalued mappings and their conjugates. Cybernetics 10 (1974), 453-464. [3] ROBERTS A. W.-VARBERG D. E.: Convex functions. New York-London, Academic Press, 1973. · Zbl 0271.26009
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. It attempts to reflect the references listed in the original paper as accurately as possible without claiming the completeness or perfect precision of the matching.


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# Homogeneity of dirac delta

I know that $$\delta(ax) = \frac{1}{|a|}\delta(x)$$ for $$a\neq0$$ in the sense of distributions. However I am confused about the inconsistency of the following computation. Consider $$g\in C^\infty_c(\mathbb{R}^2;\mathbb{R})$$ $$\int_{\mathbb{R}^2} \delta(x-ay)g(x,y)dxdy = \int_{\mathbb{R}} g(ay,y)dy$$ But using $$\delta(x-ay) = \delta(a(\frac{x}{a}- y)) = \frac{1}{|a|}\delta(\frac{x}{a} - y)$$ we compute $$\int_{\mathbb{R}^2}\frac{1}{|a|}\delta(\frac{x}{a} - y)g(x,y)dxdy = \int_{\mathbb{R}} \frac{1}{|a|}g(ay,y)dy \neq \int_{\mathbb{R}}g(ay,y)dy$$ Obviously something is going wrong here. I may be using the homogeneity condition wrong as I know in $$n$$ dimension we have $$\delta(a\mathbf{x}) = \frac{1}{|a|^n}\delta(\mathbf{x})$$

The second computation should be $$\int_{\mathbb{R}^2}\frac{1}{|a|}\delta(\frac{x}{a} - y)g(x,y)dxdy ~=~ \int_{\mathbb{R}} \frac{1}{|a|}g(x,x/a)dx ~\stackrel{x=ay}{=}~ \int_{\mathbb{R}}g(ay,y)dy.$$ In the substitution of the last equality, we exchanged integration limits if $$a<0$$.
The second computation is wrong I realize... It should be $$\int_{\mathbb{R}^2}\frac{1}{|a|}\delta(\frac{x}{a} - y)g(x,y)dxdy = \int_{\mathbb{R}} \frac{1}{|a|}\frac{g(ay,y)}{|\frac{d}{dx}(\frac{x}{a} - y)|}dy = \int_{\mathbb{R}} g(ay,y)dy$$