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Transfer out the energy of Earth gravity is the only way to solve the world energy shortage and the Earth warming problems at rhe same time and is the cheapest way. These are very special problems, therefore, it may take a very "special person" (may be not a special research team) to solve it. Why not post a challenge to quest for the solution. The result may surprise every one of you.

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Transfer out the energy of Earth gravity is the only way to solve the world energy shortage and the Earth warming problems at the same and is the cheapest way. These are very special problems, therefore, it may take a very "special person" (may be not a special research team) to solve it. Why not post a challenge to quest for the solution. The result may surprise every one of you.

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Compressed air (open hardware) motor and vehicles.

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A challenge I didn't see was the development of more efficient/better alternative fuels (whether it be biofuels, hydrogen, etc.). While fusion seems to be a viable long-term solution to replace coal/oil for energy, we need to have a stop-gap solution on the automotive side. Furthermore, plastic products made from fossil fuels are piling up in landfills. Engineered biodegradable polymers or plastics made from biofuels could lead to sustainability.

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Alternative energy sources were mentioned on the list but there are many more than just solar and fusion. While fusion has tremendous potential it could still be a long way off so in the mean time other forms need to be developed. Wind power is just beginning to become popular and has shown to provide large amounts of power but it requires a large area. Biodiesel from secondary agricultural products or from algae is a viable alternative, but it also has it drawbacks. Hydrogen fuel cells could be used to power vehicles and hydrogen could be a great way of storing energy during times of excess production from solar cells and wind turbines. All of these are viable alternatives but with further engineering developments their implementation and efficiency could greatly increase.

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The importance of good infrastructure for a city is under-rated. When I lived in Portland, OR the bus system was great and I rarely drove. I now live farther south and riding the train or bus up to Portland to visit family isn't really an option because of the infrequency or unavailability of public transportation. My only option is to drive and hope to car pool. A short train trip between towns like in Europe would be much more ideal.

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While it may be useful to make further advances in the medical field and computer technology, it is more important to assure that everybody on Earth has at least an acceptable standard of living and decrease the negative effects people are having on the source of all most all resources, the Earth. I think that the challenges concerning alternative energy sources, infrastructure, and clean water are much more important then reverse engineering the brain or medical informatics.

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I think the most important challenge is the "Advanced Personalized Learning". The advancement of people and society education is the most important challenge and will play the biggest role in deciding what other areas time and money will be invested. Having more educated citizens allows for more educated people in power and hopefully better decisions that will benefit the majority of people on the planet.

"needs. People who are struggling to find potable water and sufficient nutrition will see no benefit from personalized medicines that they cannot afford..." 

While it is apparent that all of the engineering challenges are significant in their impact on the world, the urgency and importance of their solutions are widely varied. As mentioned in some of the documents, engineering knowledge and technologies are not spread evenly throughout the world. While securing cyberspace and advancing artificial intelligence have great potential applications, a large percentage of the world's population is failing to attain the most basic of human needs. People who are struggling to find potable water and sufficient nutrition will see no benefit from personalized medicines that they cannot afford; similarly, reduced vulnerability to identity theft and increased cyberspace security is meaningless to someone living in an area lacking the infrastructure to support those issues. While I believe that all of the challenges listed by the NAE are valid in some context, it is my opinion that engineering solutions that would benefit the human population as a whole are much more significant long-term than those that only minimally enhance the lives of a select few.

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I'm surprised that issues regarding waste management didn't make the list. Currently contaminated areas pose a significant threat to human and environmental health while solutions to dealing with contamination and future waste seem inadequate in their capacity to minimize our presence on this planet.

"We should stop adding to the degradation first and then once that is under control we can worry about the damage that has been done. " 

I think that by far the most important challenge in this list is the need for a new source of energy. Obviously more efficient solar power would be nice, but fusion or nuclear power could also work. If we had a clean method for producing power (like nuclear power maybe) then we would not need to sequester carbon, it does not make sense in the first place. It is like shoveling snow as soon as the snow storm starts. A better use of your time would be to either stop the storm (analogy does not work too well here) or make a snow blower to clean it fast once it stops snowing. The same goes for the nitrogen cycle, by continuing to use fossil fuels we are making the problem worse. We should stop adding to the degradation first and then once that is under control we can worry about the damage that has been done. If an alternative to fossil fuels is found, then the smog that is present in large cities would first stop getting worse and then as time progresses, they would start to get better. This would definitely help the public health. Although it is not a miracle cure that solves all our problems, it would certainly have great health benefits associated with it. The other challenges seemed more like something to satisfy public opinion or human curiosity, and while it would certainly be nice to reverse engineer the brain or secure cyber space, I believe that the need for a cleaner energy source is a far more pressing issue. That being said, I would like to propose a far more realistic, already economically viable, and quicker solution to problem of “dirty” energy. Nuclear power! It is safe, cheap, clean, and available. People think that it is so dangerous because when they think nuclear, they immediately jump to either the nuclear bomb, or Chernobyl/Three Mile Island. While I agree that Chernobyl was a disaster, it was not something that would ever happen in the United States or with any well built reactor. The control system was built so that if there is a failure it goes to meltdown which is stupid really. All reactors in the US and every reactor built since then are designed so that if there is a problem the reactor shuts itself down. Three Mile Island while generally thought of as a disaster is actually a major success. The accident should not have happened in the first place, but once it did, it was contained and nobody was hurt. The radiation that did leak was approximately 1/6th the amount of radiation received from a chest x-ray. Nuclear power has also been around for almost 30 years since Three Mile Island, and it is much better regulated and now it has much better safety measures in place. Now if you compare that safety record against how many people have died mining coal, or the number of people that have died due to explosions at fossil fuel refineries, like the eleven that died in the Texas City BP refinery. Nuclear power has an amazing safety record. The last problem is nuclear waste. Fortunately the government has built a repository to house all the nuclear waste. It is secure and can hold enough waste to provide all the power we need for the next 100 years. I may be a little biased in my assessment of the importance of these issues because I am not planning on going into the healthcare industry and I do not particularly like working with biological systems, I prefer to work with more traditional material.

"Existing and future engineers must step forward, willing to apply their talents and opportunities to a greater cause: safeguarding others' wellbeing. " 

In western culture, engineering judgment has traditionally been held in high regard. In fact, it was one of the few occupations (including medical doctors) that were originally deemed "professions." An occupation may be called a profession if it requires advanced study (including theory) and "mastery of a specialized body of knowledge and undertake to promote, ensure, or safeguard some matter that significantly affects others' wellbeing." Engineers have been given this status (and responsibility) because of their ability to not only resolve existing issues, but because they have the problem-solving prowess required to answer the evolving needs of society. For the past six thousand years, society's problems were localized and they impacted communities of cities or regions, but the outlined challenges pose a threat because the community they impact is the whole world. Existing and future engineers must step forward, willing to apply their talents and opportunities to a greater cause: safeguarding others' wellbeing. I believe that the primary issues which necessitate engineering application, political action, and common attention are those focused on sustainability. People will only be able to survive in a stable society if adequate food, energy, and materials are available; uneven endeavors to fulfill secondary issues are in vain if they are unable to be enjoyed. Traditionally, as a society grew, they experienced "feed-back control", wherein greater needs (energy, food, materials) prompted greater production. At the increasingly global scale of needs, however, our lands may seem less fertile and endless, and the world more like an isolated island. Overconsumption (and lack of preparation) will present a situation wherein we are unable to fulfill needs. An analogy is drawn to once-inhabited, desolate islands: what were the inhabitants' thoughts when they cut down the last tree? Some challenges are more important and imminent than others, and it is easy to get carried away with fear. However, I believe that the best way to approach these challenges is to be reasonable and provide ample engineering judgment in the workplace and in our communities. Engineers everywhere must be willing to use their specialized judgment in their specific careers, and also arenas outside their profession (even if it is uncomfortable). Doing so will ensure that these great challenges are resolved and that society is able to prosper for additional millennia.

"...developing a better nuclear power generation infrastructure would have been a better item to add to the list of challenges. " 

In my opinion, developing a better nuclear power generation infrastructure would have been a better item to add to the list of challenges. Nuclear power generation technology has been developed for decades, whereas fusion has yet to be proven to be a competitive means for power generation.

"The biggest challenges the world faces today is the negative impact on the environment due to our rapidly increasing use of energy. " 

All of these challenges revolve around the world's ever growing consumption of all of our resources. One solution that would limit this demand for clean water, energy and food is to substantially curb the population growth to match what the ecosystem can handle in a healthy way. Since this is not possible for many reasons, engineers have to find a way to make things work. The biggest challenges the world faces today is the negative impact on the environment due to our rapidly increasing use of energy. Both solar and fusion energy are much cleaner than the fossil fuels our society depends on. We already know a lot about how to make solar panels so we have good ideas as to how to make it more economic and efficient. The fusion energy has so far been limited to quite a few successful lab tests. The great interest the international community has in its large scale potential is a very valuable resource. The large scale experimental reactor being built in France will provide valuable information about the design, operation, and maintenance of fusion power reactor. These two challenges are achievable but when we reap the benefits is just a matter of how much resource we devote to it today.

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I think that a good job was done of pulling together a diverse group of challenges that will interest many people in different fields.

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Dr. El-Baz, thank you for enlightening me as a fellow geologist in a way that geology is being used to solve world problems. I would be glad to assist in any way, i work as a senior office engineer at dulles airport on tunneling and building expanison but am "rooted" in geology and worked as a geotech engineer on the bigdig for many years. appplauds to you danny j bobrow

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1. Keep a running tabulation of all the comments. 2. See which ones come up the most often. 3. Have your experts comb them for the best ideas. 4. Don't get hung up on ownership. 5. Look for the"Why didn't I think of that" ideas. 6. Publish the best ideas submitted by you readers -- not verbatim, but as best summarized by your (best) editors. 7. Give a link to all the submitted comments.

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respected sir sir my openian is electrial power supply into signal type please give some information

"Imagine the economic, intellectual and inspiring activities that would result if humans could transit much more readily to other worlds." 

For long term human survival and to preserve Earth as a pleasant habitat, we need to tap into resources available in the solar system. Because we are not now able to do so, resources for human existence are drawn only from our home world. Our ability to transit through space is currently restricted by primitive spacecraft propulsion systems. Imagine the economic, intellectual and inspiring activities that would result if humans could transit much more readily to other worlds.

"Survival, health, and happiness comes from the barest of neccesities..." 

When all else fails, as evidenced by this congressionally mandated forum, then perhaps we should each consider making our own Plan B. If one is interested in some ingenious technological or sociopolitical 'rabbit-out-of-the-hat-tr ick' to keep up the modern way of life, I haven't a clue, but I see I'm not alone in that. Plan B, as it were, is an approach to a simpler life that we voluntarily gave up decades ago, as we tend to look for more in life, we appearantly stopped looking back. Basically, it was how things got done before the advent of mass production and mass transportation. Perhaps now is the time to look [back] into methods of survival in the unlikely event that things get a little 'bumpy' in the near future. Life is actually meant to be much simpler than we have made it out to be. Survival, health, and happiness comes from the barest of neccesities, which are; shelter, heat, water, and food. These four items should be our only 'survival' concerns, the rest is trivia. As most people would have shelter, as evidenced by the housing bubble, then that leaves us with only three major concerns. If one has no source of home heating other than the conventional gas or electric heating systems, then it is advisable to search the internet or elsewhere on quadrafire wood-burning stoves, as these are very efficient sources of heat. However, multi-layered clothing should not be overlooked as the primary method, as the body is extremely efficient in producing heat. Our next concern is water. All fresh water falls from the heavens, so to speak. There is an ingenious bit of engineering developed by our ancient scholars thousands of years ago, still used today on our modern high-tech buildings. It is called a gutter. It would be advisable to look into rain-catchment systems. That leaves us one more concern; food. It is a very sad fact, and quite humbling, that I never knew until fairly recently that a seed was actually ALIVE, as in breathing, as it is an embriotic living miniature multifolded plant, awaiting only water, and the proper tempera