Many swimming pools include chlorine-based chemicals to keep the water safe to swim in. Members Group 7 are also known as Halogens. The other halogens – that is, members of the same group are Fluorine , Bromine , Iodine and Astatine. These have some properties in common with chlorine and there are also certain “trends” or patterns in the variation of properties across this group of elements. Each chlorine atom consists of 17 protons , 17 electrons plus a quantity of neutrons whose exact number depends on the particular isotope of chlorine in most cases there are 18 neutrons in each atom of chlorine. History and Discovery of Chlorine The most common compound of chlorine is sodium chloride, which is also known as “common salt” or “table salt”. Sodium chloride has been known and used for thousands of years.
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Paul Berry After building the product for Huffington Post, and owning the product and engineering groups at AOL after we were acquired, it was clear to me there was a huge gap between what the current CMS offering gave the world and what the world needed. Five years later we are at scale, moving the needle and doing to WordPress what Airbnb did to Craigslist. Social and Centralized WordPress, Drupal, and the custom CMS solutions of the world are all independent, non-connected instances that each need to be updated individually.
There are over 87 million instances of WordPress alone in the world, and each security upgrade, feature update, and every other single thing has to be updated for each site individually. By contrast, RebelMouse is a social, centralized platform built to keep up with the speed of the tech giants.
Meteorite – Association of meteorites with asteroids: If meteoritic material comes from specific regions of the asteroid belt, then the asteroids in such regions should have the chemical and mineralogical composition observed in the meteorites. The surface mineralogical composition of asteroids, in principle, can be determined directly by observations from Earth of the fraction of sunlight.
Full citation Abstract International audienceCosmic-ray exposure dating of preserved, seismically exhumed limestone normal fault scarps has been used to identify the last few major earthquakes on seismogenic faults and recover their ages and displacements through the modelling of the content of in situ [36Cl] cosmonuclide of the scarp rocks. However, previous studies neglected some parameters that contribute to 36Cl accumulation and the uncertainties on the inferred earthquake parameters were not discussed.
Through a series of synthetic profiles, we examine the effects of each factor on the resulting [36Cl], and quantify the uncertainties related to the variability of those factors. Those most affecting the concentrations are rock composition, site location, shielding resulting from the geometry of the fault scarp and associated colluvium, and scarp denudation.
In addition, 36Cl production mechanisms and rates are still being refined, but the importance of these epistemic uncertainties is difficult to assess. We then examine how pre-exposure and exposure histories of fault-zone materials are expressed in [36Cl] profiles. We show that the 36Cl approach allows unambiguous discrimination of sporadic slip versus continuous creep on these faults. By contrast, the modelling cannot discriminate whether a slip event is a single event or is composed of multiple events made of temporally clustered smaller size events.
As a result, the number of earthquakes identified is always a minimum, while the estimated displacements are maximum bounds and the ages the approximate times when a large earthquake or a cluster of smaller earthquakes have occurred. We applied our approach to a data set available on the Magnola normal fault, Central Italy, including new samples from the buried part of the scarp. Reprocessing of the data helps to refine the seismic history of the fault and quantify the uncertainties in the number of earthquakes, their ages and displacements.
We find that the Magnola fault has ruptured during at least five large earthquakes or earthquake clusters in the last 7 ka, and may presently be in a phase of intense activity Topics: Geomorphology, Palaeoseismology, Continental tectonics:
Bowen of the University of Wales, Cardiff and colleagues have dated a fragment of igneous rock reported as having been found at Stonehenge exact type unknown, but not a spotted dolerite at 14, [ or -] years, and surfaces of outcrops at Carn Menyn in Preseli at [ or -] and [ or -] years Bowen et al. This information has been interpreted as indicating that the bluestones of Stonehenge could not have been transported to the site of Stonehenge by ice, because the ice sheets were extensive enough only at c.
Chlorine dating gives an estimate of the length of time that a rock surface has been exposed to the atmosphere, by measuring the amount of Chlorine produced by exposure of the rock to cosmic radiation. If the rock or surface has been covered or buried, the date obtained will reflect the reduced time of exposure to air.
Uranium is a naturally occurring element that can be found in low levels within all rock, soil, and water. Uranium is also the highest-numbered element to be found naturally in significant quantities on earth and is always found combined with other elements. It, along with all elements with atomic weights higher than iron, are only naturally formed in supernova explosions.
My PhD research was on the geochemistry of helium and the other noble gases, followed by brief stints working on lunar soils and isotopically unusual, pre-solar grains in meteorites. This has become the core of my research. With students and collaborators, I am working on projects in Antarctica , some aimed at dating the last glaciation, others concerned with the long-term history of the ice sheet. Additional interests include the geochemistry and geomorphology of cratonic landscapes, erosion and sediment transport in the Pacific northwest, and integration of cosmogenic nuclides into geomorphic models.
The projects and publications listed elsewhere on this website provide further information. I’ve long been involved in chasing down the details of cosmogenic nuclide production, both at the surface and deep below ground.
Sealed radioactive sources are used in industrial radiography, gauging applications, and mineral analysis. The attributes of naturally decaying atoms, known as radioisotopes, give rise to their multiple applications across many aspects of modern day life see also information paper on The Many Uses of Nuclear Technology. Industrial tracers Radioisotopes are used by manufacturers as tracers to monitor fluid flow and filtration, detect leaks, and gauge engine wear and corrosion of process equipment.
Reclamation Library Glossary. Listed alphabetically below are definitions for terms commonly used by the Bureau of Reclamation. Clickable alphabet links have been provided at the beginning and end of the glossary to aid in searches.
Share this article Share He said: It hung about and didn’t move yesterday because there was no wind. The cloud seems to have dispersed today though. Initial reports were of a fire at Birling Gap, but there’s been no fire. But some claims include that there could be a leak from industrial plants across the Channel on France’s northern coastline.
As most of the work is happening underground, specialist rescue teams are on duty around the clock to keep workers safe. A spokesman for the works said all sites are constantly monitored and everything is working normally. Dramatic pictures of the cloud’s distinctive yellow haze, and witness reports mentioning strong smells, have sparked speculation that the mist may contain chlorine gas. The bizarre fog crept inland along the coastline from Bexhill to Birling Gap, part of Seven Sisters national park.
Pop up tents and staff in protective suits gave the first few patients full decontamination treatment, but this was scrapped after clinical advice said the level of attention was not necessary. Neighbouring hospitals helped with the influx of patients by taking on people whose ailments did not relate to the worrying gas cloud.
A police spokesman added: In concerned locals in Kent, Surrey and Sussex raised the alarm about smelly air wafting in from the sea. It was revealed a factory in Rouen, France, had accidentally released the harmless gas, mercaptan, which had wafted across the English Channel.
Share this article Share Many die within minutes of inhaling the gas. The maximum life expectancy is ten minutes after exposure. Those lucky enough to survive, due to receiving a much smaller exposure — such as from touching a contaminated person — often suffer permanent nerve and brain damage. The discovery of the nerve agent — meaning it acts upon the nervous system — came after the Third Reich high command ordered scientists to develop pesticides and insecticides to ensure Germany did not need to rely on imported food while it prepared for war.
Schrader, 33, headed up a team assigned to the task.
Geosciences, an international, peer-reviewed Open Access journal. Typhoon Jebi struck Japan on the 4 September , damaging and inundating many coastal areas along Osaka Bay due to the high winds, a storm surge, and wind driven waves.
Search terrestrial age The terrestrial age is the time that has elapsed since a meteorite fell to Earth. It can be calculated from the abundances of some relatively short-lived radioactive isotopes that were formed, while the meteorite was in space, as a result of bombardment by cosmic rays. After the meteorite lands, no more of these radioactive isotopes are made and the ones already in the rock continue to decay at a steady known rate, thus serving as a kind of clock.
Terrestrial ages are usually determined from the isotopes carbon , beryllium , and chlorine Most meteorites weather quickly in the oxidizing environment of Earth. However, other meteorites fell at more fortuitous locations and were preserved, e. Some of them have been preserved for 40, years or more. The oldest of all are fossil meteorites, preserved in sediments or in other geologic strata conducive to preservation, of which the record-holder is the meteorite of Osterplana, Sweden, that was found in imbedded in some limestone.
This limestone, which dates from Ordovician times, showed that the embedded meteorite had fallen million years ago. This just beats out the Brunflo meteorite, also found in Swedish limestone in , which has a terrestrial age of million years. As with true fossils, most of the original meteoritic minerals in fossil meteorites has been replaced by terrestrial minerals leaving only the outer structure of the meteorite preserved.
Although both meteorites have been classified as chondrites, only their chondritic structure remains as evidence of their extraterrestrial origins. The oldest intact meteorite is the Lake Murray iron. A single mass with a thick iron- shale was found in a gully in Oklahoma, in
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Bring fact-checked results to the top of your browser search. Principles of isotopic dating All absolute isotopic ages are based on radioactive decay , a process whereby a specific atom or isotope is converted into another specific atom or isotope at a constant and known rate. Most elements exist in different atomic forms that are identical in their chemical properties but differ in the number of neutral particles—i.
For a single element, these atoms are called isotopes. Because isotopes differ in mass, their relative abundance can be determined if the masses are separated in a mass spectrometer see below Use of mass spectrometers. Radioactive decay can be observed in the laboratory by either of two means:
Uranium is a chemical element with symbol U and atomic number It is a silvery-grey metal in the actinide series of the periodic table.A uranium atom has 92 protons and 92 electrons, of which 6 are valence m is weakly radioactive because all isotopes of uranium are unstable, with half-lives varying between , years and billion years.
Transcript The relative paralysis of our arteries for hours after eating fast food and cheesecake may also occur after olive oil. Olive oil was found to have the same impairment to endothelial function as the rest of these high-fat meals. Hundreds of studies have shown that the test can give a false negative result. Other oils have also been shown to have deleterious results on endothelial function; a significant and constant decrease in endothelial function three hours after each meal, independent of the type of oil, and whether the oil was fresh, or deep fried.
Olive oil may be better than omega rich oils, or saturated fats, but most of the studies showing adverse effects were done on regular, refined olive oil, not extra virgin. But what does that mean for our arteries? Extra virgin olive oil may have more of a neutral effect, compared to butter, which exerted a noxious effect that lasted for up to six hours—basically right up to our next meal.