Nuclear fission - Nuclear fission - The stages of fission: A pictorial representation of the sequence of events in the fission of a heavy nucleus is given in Figure 3. The approximate time elapse between stages of the process is indicated at the bottom of the Figure. When a heavy nucleus undergoes fission, a variety of fragment pairs may be formed, depending on the distribution of neutrons. Type 2 diabetes is characterised by mitochondrial dysfunction, h Mitochondria play a key role in maintaining cellular metabolic homeostasis. These organelles have a high plasticity and are involved in dynamic processes such as mitochondrial fusion and fission, mitophagy and mitochondrial biogenesis.
Posted By Paul Kafasis on September 17th, 2012 Ember 1 5 – versatile digital scrapbook.
Since 2006, our application Fission has been one of the most popular ways to edit audio on the Mac, with none of the quality loss caused by typical audio editors. It's been great for quick edits of recordings from both Audio Hijack Pro and Piezo, as well as creating iPhone ringtones, editing iTunes Music Store files, and more. At six years old, however, Fission was ready for a big update. Back in April, we first previewed the next generation of Fission to members of our mailing list.
Now, half a year after first previewing it, we're finally ready to unveil the newest version of Fission to the world.
Fission 2 Key Features
Export any file to MP3, AAC, FLAC, Apple Lossless, AIFF, or WAV
Batch convert dozens of files at once, with the Batch Converter
Share audio to SoundCloud.com
Chapterized AAC files make creating enhanced podcasts a snap
A gorgeous and easy-to-use new interface
And of course, much more
What's New
If you've used Fission before, you'll immediately see that the most obvious change is its appearance. Fission now offers both a dark and a light theme, as seen above, both of which have been overhauled with fantastic new art. It's not just a re-skin, however, as we've worked hard on the user experience as well. Every aspect of Fission has been examined and considered, with enhancements made across the board. The editing workflow is a snap to learn for new users, while existing users of Fission will be instantly familiar with version 2.
We've also packed in several major new features to make editing audio easier than ever. First up, that includes support for exporting directly to all major audio formats. You can still save losslessly to your file's original format, of course, but now you can export your audio to MP3, AAC, Apple Lossless, FLAC, AIFF, or WAV too.
Fission's new Export options
If you want to convert multiple files, Fission has you covered there too, with the new Batch Converter. Drop an album's worth of FLAC files on the Batch Converter, and you can have a folder full of MP3s with just 2 clicks. Converting from one format to another format couldn't be simpler.
Speaking of FLAC, Fission now has full support for the popular lossless audio format. FLAC files can be opened, edited, and saved, making it possible to change them as needed, or just export them to a smaller format for portability. Fission 2 now also supports WAV audio files, in addition to its 'original four' formats of MP3, AAC, Apple Lossless, and AIFF.
Improvements to saving aren't limited to just file formats either, as Fission now has support for publishing to SoundCloud. SoundCloud is the world's leading social sound platform, allowing anyone to create sounds and share them everywhere. With SoundCloud support in Fission, it's now easier than ever to get audio onto the web and to share it with others.
Handy SoundCloud Integration
On top of all that, we tossed in the ability to open multiple audio files at once for easy joining or multitasking, fast creation of Chapterized AAC files for enhanced podcasts, improved iPhone ringtone saving, and more. We're incredibly proud of Fission 2, and we think you're going to love it. If you need to edit audio on your Mac, you just can't go wrong using Fission.
Get Fission 2 Now
Fission 2 runs on Mac OS X 10.6 and up, with a test drive available for download. When you're ready to purchase, you can buy a license key to unlock the full version directly through our store. You can also purchase and download Fission right through Apple's App Store.1
Already Own a License for Fission?
If you purchased Fission before April 1st, 2012 (your license key will start with KRBA-), you're eligible to upgrade to Fission 2 at a heavily discounted price.2
If you purchased Fission on or after April 1st, 2012, you'll be receiving a complimentary upgrade to Fission 2! Watch your email inbox for full details on moving up to Fission 2, free of charge.
Fusion 2 Any 1 Sushi
Go Forth and Edit!
After many, many months of development, we're thrilled to get Fission 2 into your hands. If you have any questions or feedback, contact us directly. Otherwise, enjoy Fission 2!
Footnotes:
1. Looking for our other apps in the Mac App Store? Unfortunately, Apple's many restrictions preclude most of our applications from appearing there. As mentioned in this Knowledge Base article, we'll always sell our software directly, even when it also appears in the Mac App Store. ↩
2. Unfortunately, as you may be aware, Apple provides no way for us to move existing users into the Mac App Store. If you own a Fission 1 license, we're only able to provide a discounted upgrade through direct purchase.
You are of course able to buy Fission 2 directly through the App Store, but we have no way to provide the appropriate discount there. As such, we recommend all upgraders purchase Fission directly through our store. ↩
- Fundamentals of the fission process
- The phenomenology of fission
Our editors will review what you've submitted and determine whether to revise the article.
Join Britannica's Publishing Partner Program and our community of experts to gain a global audience for your work! Ellis P. SteinbergNuclear fission, subdivision of a heavy atomic nucleus, such as that of uranium or plutonium, into two fragments of roughly equal mass. Safari browser update mac. The process is accompanied by the release of a large amount of energy.
Fission 2020
In nuclear fission the nucleus of an atom breaks up into two lighter nuclei. The process may take place spontaneously in some cases or may be induced by the excitation of the nucleus with a variety of particles (e.g., neutrons, protons, deuterons, or alpha particles) or with electromagnetic radiation in the form of gamma rays. In the fission process, a large quantity of energy is released, radioactive products are formed, and several neutrons are emitted. These neutrons can induce fission in a nearby nucleus of fissionable material and release more neutrons that can repeat the sequence, causing a chain reaction in which a large number of nuclei undergo fission and an enormous amount of energy is released. If controlled in a nuclear reactor, such a chain reaction can provide power for society's benefit. If uncontrolled, as in the case of the so-called atomic bomb, it can lead to an explosion of awesome destructive force.
The discovery of nuclear fission has opened a new era—the 'Atomic Age.' The potential of nuclear fission for good or evil and the risk/benefit ratio of its applications have not only provided the basis of many sociological, political, economic, and scientific advances but grave concerns as well. Even from a purely scientific perspective, the process of nuclear fission has given rise to many puzzles and complexities, and a complete theoretical explanation is still not at hand.
History of fission research and technology
The term fission was first used by the German physicists Lise Meitner and Otto Frisch in 1939 to describe the disintegration of a heavy nucleus into two lighter nuclei of approximately equal size. The conclusion that such an unusual nuclear reaction can in fact occur was the culmination of a truly dramatic episode in the history of science, and it set in motion an extremely intense and productive period of investigation.
The story of the discovery of nuclear fission actually began with the discovery of the neutron in 1932 by James Chadwick in England. Shortly thereafter Enrico Fermi and his associates in Italy undertook an extensive investigation of the nuclear reactions produced by the bombardment of various elements with this uncharged particle. In particular, these workers observed (1934) that at least four different radioactive species resulted from the bombardment of uranium with slow neutrons. These newly discovered species emitted beta particles and were thought to be isotopes of unstable 'transuranium elements' of atomic numbers 93, 94, and perhaps higher. There was, of course, intense interest in examining the properties of these elements, and many radiochemists participated in the studies. The results of these investigations, however, were extremely perplexing, and confusion persisted until 1939 when Otto Hahn and Fritz Strassmann in Germany, following a clue provided by Irène Joliot-Curie and Pavle Savić in France (1938), proved definitely that the so-called transuranic elements were in fact radioisotopes of barium, lanthanum, and other elements in the middle of the periodic table.
That lighter elements could be formed by bombarding heavy nuclei with neutrons had been suggested earlier (notably by the German chemist Ida Noddack in 1934), but the idea was not given serious consideration because it entailed such a broad departure from the accepted views of nuclear physics and was unsupported by clear chemical evidence. Armed with the unequivocal results of Hahn and Strassmann, however, Meitner and Frisch invoked the recently formulated liquid-drop model of the nucleus to give a qualitative theoretical interpretation of the fission process and called attention to the large energy release that should accompany it. There was almost immediate confirmation of this reaction in dozens of laboratories throughout the world, and within a year more than 100 papers describing most of the important features of the process were published. These experiments confirmed the formation of extremely energetic heavy particles and extended the chemical identification of the products.
Alivecolors 1 2 1519 – graphics and photo editor software. The chemical evidence that was so vital in leading Hahn and Strassmann to the discovery of nuclear fission was obtained by the application of carrier and tracer techniques. Since invisible amounts of the radioactive species were formed, their chemical identity had to be deduced from the manner in which they followed known carrier elements, present in macroscopic quantity, through various chemical operations. Known radioactive species were also added as tracers and their behaviour was compared with that of the unknown species to aid in the identification of the latter. Over the years, these radiochemical techniques have been used to isolate and identify some 34 elements from zinc (atomic number 30) to gadolinium (atomic number 64) that are formed as fission products. The wide range of radioactivities produced in fission makes this reaction a rich source of tracers for chemical, biologic, and industrial use.
Passdirector 2 5 2. Although the early experiments involved the fission of ordinary uranium with slow neutrons, it was rapidly established that the rare isotope uranium-235 was responsible for this phenomenon. The more abundant isotope uranium-238 could be made to undergo fission only by fast neutrons with energy exceeding 1 MeV. The nuclei of other heavy elements, such as thorium and protactinium, also were shown to be fissionable with fast neutrons; and other particles, such as fast protons, deuterons, and alphas, along with gamma rays, proved to be effective in inducing the reaction.
We've also packed in several major new features to make editing audio easier than ever. First up, that includes support for exporting directly to all major audio formats. You can still save losslessly to your file's original format, of course, but now you can export your audio to MP3, AAC, Apple Lossless, FLAC, AIFF, or WAV too.
Fission's new Export options
If you want to convert multiple files, Fission has you covered there too, with the new Batch Converter. Drop an album's worth of FLAC files on the Batch Converter, and you can have a folder full of MP3s with just 2 clicks. Converting from one format to another format couldn't be simpler.
Speaking of FLAC, Fission now has full support for the popular lossless audio format. FLAC files can be opened, edited, and saved, making it possible to change them as needed, or just export them to a smaller format for portability. Fission 2 now also supports WAV audio files, in addition to its 'original four' formats of MP3, AAC, Apple Lossless, and AIFF.
Improvements to saving aren't limited to just file formats either, as Fission now has support for publishing to SoundCloud. SoundCloud is the world's leading social sound platform, allowing anyone to create sounds and share them everywhere. With SoundCloud support in Fission, it's now easier than ever to get audio onto the web and to share it with others.
Handy SoundCloud Integration
On top of all that, we tossed in the ability to open multiple audio files at once for easy joining or multitasking, fast creation of Chapterized AAC files for enhanced podcasts, improved iPhone ringtone saving, and more. We're incredibly proud of Fission 2, and we think you're going to love it. If you need to edit audio on your Mac, you just can't go wrong using Fission.
Get Fission 2 Now
Fission 2 runs on Mac OS X 10.6 and up, with a test drive available for download. When you're ready to purchase, you can buy a license key to unlock the full version directly through our store. You can also purchase and download Fission right through Apple's App Store.1
Already Own a License for Fission?
If you purchased Fission before April 1st, 2012 (your license key will start with KRBA-), you're eligible to upgrade to Fission 2 at a heavily discounted price.2
If you purchased Fission on or after April 1st, 2012, you'll be receiving a complimentary upgrade to Fission 2! Watch your email inbox for full details on moving up to Fission 2, free of charge.
Fusion 2 Any 1 Sushi
Go Forth and Edit!
After many, many months of development, we're thrilled to get Fission 2 into your hands. If you have any questions or feedback, contact us directly. Otherwise, enjoy Fission 2!
Footnotes:
1. Looking for our other apps in the Mac App Store? Unfortunately, Apple's many restrictions preclude most of our applications from appearing there. As mentioned in this Knowledge Base article, we'll always sell our software directly, even when it also appears in the Mac App Store. ↩
2. Unfortunately, as you may be aware, Apple provides no way for us to move existing users into the Mac App Store. If you own a Fission 1 license, we're only able to provide a discounted upgrade through direct purchase.
You are of course able to buy Fission 2 directly through the App Store, but we have no way to provide the appropriate discount there. As such, we recommend all upgraders purchase Fission directly through our store. ↩
- Fundamentals of the fission process
- The phenomenology of fission
Our editors will review what you've submitted and determine whether to revise the article.
Join Britannica's Publishing Partner Program and our community of experts to gain a global audience for your work! Ellis P. SteinbergNuclear fission, subdivision of a heavy atomic nucleus, such as that of uranium or plutonium, into two fragments of roughly equal mass. Safari browser update mac. The process is accompanied by the release of a large amount of energy.
Fission 2020
In nuclear fission the nucleus of an atom breaks up into two lighter nuclei. The process may take place spontaneously in some cases or may be induced by the excitation of the nucleus with a variety of particles (e.g., neutrons, protons, deuterons, or alpha particles) or with electromagnetic radiation in the form of gamma rays. In the fission process, a large quantity of energy is released, radioactive products are formed, and several neutrons are emitted. These neutrons can induce fission in a nearby nucleus of fissionable material and release more neutrons that can repeat the sequence, causing a chain reaction in which a large number of nuclei undergo fission and an enormous amount of energy is released. If controlled in a nuclear reactor, such a chain reaction can provide power for society's benefit. If uncontrolled, as in the case of the so-called atomic bomb, it can lead to an explosion of awesome destructive force.
The discovery of nuclear fission has opened a new era—the 'Atomic Age.' The potential of nuclear fission for good or evil and the risk/benefit ratio of its applications have not only provided the basis of many sociological, political, economic, and scientific advances but grave concerns as well. Even from a purely scientific perspective, the process of nuclear fission has given rise to many puzzles and complexities, and a complete theoretical explanation is still not at hand.
History of fission research and technology
The term fission was first used by the German physicists Lise Meitner and Otto Frisch in 1939 to describe the disintegration of a heavy nucleus into two lighter nuclei of approximately equal size. The conclusion that such an unusual nuclear reaction can in fact occur was the culmination of a truly dramatic episode in the history of science, and it set in motion an extremely intense and productive period of investigation.
The story of the discovery of nuclear fission actually began with the discovery of the neutron in 1932 by James Chadwick in England. Shortly thereafter Enrico Fermi and his associates in Italy undertook an extensive investigation of the nuclear reactions produced by the bombardment of various elements with this uncharged particle. In particular, these workers observed (1934) that at least four different radioactive species resulted from the bombardment of uranium with slow neutrons. These newly discovered species emitted beta particles and were thought to be isotopes of unstable 'transuranium elements' of atomic numbers 93, 94, and perhaps higher. There was, of course, intense interest in examining the properties of these elements, and many radiochemists participated in the studies. The results of these investigations, however, were extremely perplexing, and confusion persisted until 1939 when Otto Hahn and Fritz Strassmann in Germany, following a clue provided by Irène Joliot-Curie and Pavle Savić in France (1938), proved definitely that the so-called transuranic elements were in fact radioisotopes of barium, lanthanum, and other elements in the middle of the periodic table.
That lighter elements could be formed by bombarding heavy nuclei with neutrons had been suggested earlier (notably by the German chemist Ida Noddack in 1934), but the idea was not given serious consideration because it entailed such a broad departure from the accepted views of nuclear physics and was unsupported by clear chemical evidence. Armed with the unequivocal results of Hahn and Strassmann, however, Meitner and Frisch invoked the recently formulated liquid-drop model of the nucleus to give a qualitative theoretical interpretation of the fission process and called attention to the large energy release that should accompany it. There was almost immediate confirmation of this reaction in dozens of laboratories throughout the world, and within a year more than 100 papers describing most of the important features of the process were published. These experiments confirmed the formation of extremely energetic heavy particles and extended the chemical identification of the products.
Alivecolors 1 2 1519 – graphics and photo editor software. The chemical evidence that was so vital in leading Hahn and Strassmann to the discovery of nuclear fission was obtained by the application of carrier and tracer techniques. Since invisible amounts of the radioactive species were formed, their chemical identity had to be deduced from the manner in which they followed known carrier elements, present in macroscopic quantity, through various chemical operations. Known radioactive species were also added as tracers and their behaviour was compared with that of the unknown species to aid in the identification of the latter. Over the years, these radiochemical techniques have been used to isolate and identify some 34 elements from zinc (atomic number 30) to gadolinium (atomic number 64) that are formed as fission products. The wide range of radioactivities produced in fission makes this reaction a rich source of tracers for chemical, biologic, and industrial use.
Passdirector 2 5 2. Although the early experiments involved the fission of ordinary uranium with slow neutrons, it was rapidly established that the rare isotope uranium-235 was responsible for this phenomenon. The more abundant isotope uranium-238 could be made to undergo fission only by fast neutrons with energy exceeding 1 MeV. The nuclei of other heavy elements, such as thorium and protactinium, also were shown to be fissionable with fast neutrons; and other particles, such as fast protons, deuterons, and alphas, along with gamma rays, proved to be effective in inducing the reaction.
Fission 20
In 1939, Frédéric Joliot-Curie, Hans von Halban, and Lew Kowarski found that several neutrons were emitted in the fission of uranium-235, and this discovery led to the possibility of a self-sustaining chain reaction. Fermi and his coworkers recognized the enormous potential of such a reaction if it could be controlled. On Dec. 2, 1942, they succeeded in doing so, operating the world's first nuclear reactor. Known as a 'pile,' this device consisted of an array of uranium and graphite blocks and was built on the campus of the University of Chicago.
The secret Manhattan Project, established not long after the United States entered World War II, developed the atomic bomb. Once the war had ended, efforts were made to develop new reactor types for large-scale power generation, giving birth to the nuclear power industry.
Fission 2.5 Tuff
- key people
- related topics
