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    which is most likely why many scientists reject the cold fusion theory? there is too much waste involved in the process. cold fusion experiments have been conducted at room temperature only. the process does not produce enough energy to meet the needs of modern humans. the original results have not been replicated consistently and reliably.

    James

    Guys, does anyone know the answer?

    get which is most likely why many scientists reject the cold fusion theory? there is too much waste involved in the process. cold fusion experiments have been conducted at room temperature only. the process does not produce enough energy to meet the needs of modern humans. the original results have not been replicated consistently and reliably. from EN Bilgi.

    What is the current scientific thinking on cold fusion? Is there any possible validity to this phenomenon?

    Scientific American is the essential guide to the most awe-inspiring advances in science and technology, explaining how they change our understanding of the world and shape our lives.

    THE SCIENCES

    What is the current scientific thinking on cold fusion? Is there any possible validity to this phenomenon?

    October 21, 1999 ADVERTISEMENT

    Peter N. Saeta, an assistant professor of physics at Harvey Mudd College, responds:

    Eight years ago researchers Martin Fleischmann and Stanley Pons, then both at the University of Utah, made headlines around the world with their claim to have achieved fusion in a simple tabletop apparatus working at room temperature. Other experimenters failed to replicate their work, however, and most of the scientific community no longer considers cold fusion a real phenomenon. Nevertheless, research continues, and a small but very vocal minority still believes in cold fusion.

    Michael J. Schaffer, a senior scientist at one of the major U.S. fusion research laboratories (his employer has requested not to be identified), has provided this historical overview, along with a rather moderate assessment current status of cold fusion:

    "Because cold fusion is still an unresolved and controversial subject that generates strong opinions and passionate debate among scientists, I begin by stating up front that I am a mainstream plasma physicist researching fusion energy. I also read many of the papers published on cold fusion, however. I attended the last three International Conferences on Cold Fusion, and I myself ran two sets of cold fusion experiments, both with no clear evidence of excess power release. Overall, I consider myself to be a fairly neutral observer.

    "To understand the controversy, it helps to know some basic facts about fusion. Fusion is a nuclear reaction wherein two smaller nuclei join (fuse) to form a new, larger nucleus. When that large nucleus is unstable, it quickly breaks apart and releases energy. The big difficulty is that because the initial nuclei are all positively charged, they are strongly repelled as they approach one another. Therefore, only nuclei having a high kinetic energy approach closely enough to fuse. High-speed nuclei can be made on the earth either by particle accelerators or by extremely high temperatures--on the order of 50 million degrees Celsius or more. In controlled 'magnetic' fusion energy experiments, such as tokamaks and others, a magnetically confined plasma is heated by electromagnetic waves or neutral particle beams. In 'inertial' fusion energy experiments, tiny pellets are compressed and heated by powerful pulsed laser or ion beams.

    "Cold fusion claims to release measurable energy from fusion reactions at or near room temperature when deuterium is dissolved in a solid, usually palladium metal. The idea, which has its roots in research going back to the 1920s, is that hydrogen and its isotopes can dissolve to such high concentrations in certain solids that the hydrogen nuclei approach closer to one another than even in solid hydrogen. Furthermore, negative electrical charges from the electrons of the solid host partly cancel the repulsion between the nuclei. Early experiments did not detect any signs of fusion, however. Furthermore, modern theoretical calculations show that the proposed effects, while real, are much too small to produce detectable rates of fusion.

    "Electrochemists Martin Fleischmann and Stanley Pons decided to revisit room-temperature fusion. Their technique is to pass current through an electrolytic cell consisting of a palladium (Pd) cathode, platinum (Pt) anode and LiOD (a compound of lithium, oxygen and deuterium, or heavy hydrogen) electrolyte in heavy water (water containing deuterium in place of the ordinary hydrogen). The cathodic reaction liberates unbound atoms of deuterium (D), which enter palladium much more rapidly than do deuterium molecules. Under proper conditions, the concentration can build up to 0.9 or more deuterium atoms per palladium atom, at which point the loss of deuterium balances its rate of implantation. Pons and Fleischmann's cells were part of a calorimeter (heat-measuring device), whose temperature rise on a few occasions indicated on the order of 10 percent excess power, that is, about 10 percent more power leaving the cell than electrical power used to run it. Pons and Fleischmann announced their results at a now famous news conference on March 23, 1989. They also thought they had detected gamma radiation characteristic of neutrons passing through water, but these results later had to be retracted.

    "There was an immediate rush to reproduce the Pons and Fleischmann experiments. A few experimenters reported success, many others failure. Even those who reported success had difficulty reproducing their results. Furthermore, no one was seeing the expected fusion products. The three known D + D reactions are:

    D + D --> H + T (two deuterium nuclei yield a hydrogen nucleus and tritium, a heavy hydrogen isotope containing two neutrons) or

    D + D ---> n + 3He (yielding a neutron and helium 3, a light isotope of helium), or

    D + D ---> 4He + gamma (yielding normal helium 4 and a gamma ray).

    "The first two reactions are equally probable, and if one watt of nuclear power were produced, the neutron and tritium production would be easy to measure. But they could not be detected; if they were present at all, it was only at an extremely low level. The third D + D reaction normally proceeds much more slowly than the first two. Some experiments eventually did report helium 4 production, although great care must be used to avoid contamination by trace amounts of helium normally present in the air. This led many cold fusion researchers to postulate that somehow the third fusion reaction was catalyzed in the palladium. Moreover, it was necessary to postulate the suppression of the gamma radiation, which was never observed. There is no widely accepted theory that might explain such effects, however. Therefore, most of the scientific community concluded that the 'Pons and Fleischmann effect' was experimental error.

    Source : www.scientificamerican.com

    Nuclear Fission and Nuclear Fusion Flashcards

    Start studying Nuclear Fission and Nuclear Fusion. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

    Nuclear Fission and Nuclear Fusion

    2.8 81 Reviews

    Research into nuclear fusion will likely require a large investment of time and money before it might be used as an energy source.

    Which statement best describes the benefits that would make the investment worthwhile?

    Fusion requires a large amount of energy and occurs in stars.

    Fusion produces large amounts of energy, and the fuel is found on Earth.

    Fusion produces no radioactive waste, and the fuel is plentiful.

    Fusion requires little energy to begin and would continue through a chain reaction.

    Click card to see definition 👆

    NOT D B

    Click again to see term 👆

    Which is most likely why many scientists reject the cold fusion theory?

    There is too much waste involved in the process.

    Cold fusion experiments have been conducted at room temperature only.

    The process does not produce enough energy to meet the needs of modern humans.

    The original results have not been replicated consistently and reliably.

    Click card to see definition 👆

    D

    Click again to see term 👆

    1/14 Created by brittany_thing2

    Terms in this set (14)

    Research into nuclear fusion will likely require a large investment of time and money before it might be used as an energy source.

    Which statement best describes the benefits that would make the investment worthwhile?

    Fusion requires a large amount of energy and occurs in stars.

    Fusion produces large amounts of energy, and the fuel is found on Earth.

    Fusion produces no radioactive waste, and the fuel is plentiful.

    Fusion requires little energy to begin and would continue through a chain reaction.

    NOT D B

    Which is most likely why many scientists reject the cold fusion theory?

    There is too much waste involved in the process.

    Cold fusion experiments have been conducted at room temperature only.

    The process does not produce enough energy to meet the needs of modern humans.

    The original results have not been replicated consistently and reliably.

    D

    Which statement is true about nuclear fusion?

    It is caused by the same process that causes nuclear fission.

    It does not occur naturally in the solar system.

    It has very low activation energy.

    It produces nearly all the elements that are heavier than helium.

    NOT A

    How does critical mass play a role in nuclear reactions?

    It is the minimum amount of material needed to start a fission reaction.

    It is the minimum amount of material needed to start a fusion reaction.

    It is the minimum amount of material needed to sustain a fission reaction.

    It is the minimum amount of material needed to sustain a fusion reaction.

    C

    Which is a characteristic of nuclear fusion?

    produces radioactive waste

    involves the collision of two nuclei

    commonly used by humans as an energy source

    requires very little activation energy

    B

    Why is it important for scientists to replicate each other's experiments?

    to determine if important scientific results are repeatable

    to help the research of other scientists

    to determine if slight alterations in the experiment can affect the result

    to further their own research

    A

    Which equation demonstrates that nuclear fusion forms elements that are heavier than helium?

    B

    Which element is nuclear fusion least likely to produce?

    hydrogen, which has an approximate mass of 1

    chlorine, which has an approximate mass of 35

    argon, which has an approximate mass of 39

    silicon, which has an approximate mass of 28

    A

    Which type of reaction does this diagram represent?

    mc007-1.jpg

    nuclear fusion because nuclei combine to form a heavy nucleus

    nuclear fission because an atom is splitting into two large fragments of comparable mass

    nuclear fusion because a large amount of energy is

    being released

    nuclear fission because the resulting products are not radioactive

    B

    Which is a characteristic of nuclear fusion but NOT nuclear fission?

    releases large amounts of energy

    is the energy source of stars

    is used in electric power plants

    requires little energy to occur

    B

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    Cold fusion died 25 years ago, but the research lives on

    Scientists continue to study unusual heat-generating effects, some hoping for vindication, others for an eventual payday

    NUCLEAR POWER

    Cold fusion died 25 years ago, but the research lives on

    Cold fusion died 25 years ago, but the research lives on Scientists continue to study unusual heat-generating effects, some hoping for vindication, others for an eventual payday

    November 7, 2016 | A version of this story appeared in Volume 94, Issue 44

    Credit: James Krieger/C&EN

    Some 7,000 people attended a hastily organized cold fusion session at the ACS national meeting in Dallas in 1989, hopeful that word of the newly announced phenomenon was true.

    Howard J. Wilk is a long-term unemployed synthetic organic chemist living in Philadelphia. Like many pharmaceutical researchers, he has suffered through the drug industry’s R&D downsizing in recent years and now is underemployed in a nonscience job. With extra time on his hands, Wilk has been tracking the progress of a New Jersey-based company called Brilliant Light Power (BLP).

    IN BRIEF

    In 1989, the scientific world was turned upside down when two researchers announced they had tamed the power of nuclear fusion in a simple electrolysis cell. The excitement quickly died when the scientific community came to a consensus that the findings weren’t real—“cold fusion” became a synonym for junk science. In the quarter-century since, a surprising number of researchers continue to report unexplainable excess heat effects in similar experiments, and several companies have announced plans to commercialize technologies, hoping to revolutionize the energy industry. Yet, no one has delivered on their promises. In the pages that follow, C&EN explores several possible conclusions: The claims are correct, but need more time to develop; those making the claims are committing an elaborate ruse; or it really is junk science that won’t go away.

    The company is one of several that are developing processes that collectively fall into the category of new energy technologies. This movement is largely a reincarnation of cold fusion, the short-lived, quickly dismissed phenomenon from the late 1980s of achieving nuclear fusion in a simple benchtop electrolysis device.

    In 1991, BLP’s founder, Randell L. Mills, announced at a press conference in Lancaster, Pa., that he had devised a theory in which the electron in hydrogen could transition from its normal ground energy state to previously unknown lower and more stable states, liberating copious amount of energy in the process. Mills named this curious new type of shrunken hydrogen the hydrino, and he has been at work ever since to develop a commercial device to harness its power and make it available to the world.

    Wilk has studied Mills’s theory, read Mills’s papers and patents, and carried out his own calculations on the hydrino. Wilk has gone so far as to attend a demonstration at BLP’s facility in Cranbury, N.J., where he discussed the hydrino with Mills. After all that, Wilk says he still can’t tell if Mills is a titanic genius, is self-delusional, or is something in between.

    This story line is a common refrain for the researchers and companies involved. It all got started in 1989, when electrochemists Martin Fleischmann and Stanley Pons made the stunning announcement at a press conference at the University of Utah that they had tamed the power of nuclear fusion in an electrolysis cell.

    When the researchers applied a current to the cell, they thought deuterium atoms from heavy water that had penetrated into the palladium cathode were fusing to form helium atoms. The excess energy from the process dissipated as heat. Fleischmann and Pons said this process could not be caused by any known chemical reaction, and the nuclear reaction term “cold fusion” was attached to it.

    From hopes raised to hopes dashed: the story of cold fusion’s rise and fall, told in headlines ripped from the pages of C&EN.

    Click to expand the full list. ▼

    Want more? A list of recent books on cold fusion and related phenomenon.

    Click to expand the full list. ▼

    After months of investigating Fleischmann and Pons’s puzzling observations, however, the scientific community came to a consensus that the effect was inconsistent or nonexistent and that the scientists had made experimental errors. The research was summarily condemned, and cold fusion became a synonym for junk science.

    Cold fusion and making hydrinos both hold the holy-grail promise of generating endless amounts of cheap, pollution-free energy. Scientists were frustrated by cold fusion. They wanted to believe it, but their collective wisdom told them it was all wrong. Part of the problem was they had no generally accepted theory to guide them and explain the proposed phenomenon—as physicists like to say, no experiment should be believed until it has been confirmed by theory.

    Mills has his own theory, but many scientists don’t believe it and think the hydrino improbable. The research community has stopped short of the public dismissal it gave cold fusion and has tended to just ignore Mills and his work. Mills has reciprocated by trying to stay out from under the shadow of cold fusion.

    Credit: SRI International

    In a photo from 2012, Michael McKubre, one of the original cold fusion researchers, inspects a component of SRI International’s Micromass 5400 mass spectrometer, an instrument dedicated to measuring 3He and 4He produced in palladium-deuterium and palladium-hydrogen LENR.

    Source : cen.acs.org

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    James 7 month ago
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