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Electropositive Shark Repellent
Electropositive metals (EPMs) are a new class of shark repellent materials that produce a measurable voltage when immersed in an electrolyte such as seawater. The voltages produced are as high as 1.75 VDC in seawater. It is hypothesized that this voltage overwhelms the ampullary organ in sharks, producing a repellent action. Since bony fish lack the ampullary organ, the repellent is selective to sharks and rays. The process is electrochemical, so no external power input is required. As chemical work is done, the metal is lost in the form of corrosion. Depending on the alloy or metal utilized and its thickness, the electropositive repellent effect lasts up to 48 hours. The reaction of the electropositive metal in seawater produces hydrogen gas bubbles and an insoluble nontoxic hydroxide as a precipitate which settles downward in the water column. History SharkDefense made the discovery of electrochemical shark repellent effects on May 1, 2006 at South Bimini, Bahamas at the Bimi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shark Repellent
A shark repellent is any method of driving sharks away from an area. Shark repellents are a category of animal repellents. Shark repellent technologies include magnetic shark repellent, electropositive shark repellents, electrical repellents, and semiochemicals. Shark repellents can be used to protect people from sharks by driving the sharks away from areas where they are likely to kill human beings. In other applications, they can be used to keep sharks away from areas they may be a danger to themselves due to human activity. In this case, the shark repellent serves as a shark conservation method. There are some naturally occurring shark repellents; modern artificial shark repellents date to at least the 1940s, with the United States Navy using them in the Pacific Ocean theater of World War II. Natural repellents It has traditionally been believed that sharks are repelled by the smell of a dead shark; [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Post-transition Metal
The metallic elements in the periodic table located between the transition metals and the chemically weak nonmetallic metalloids have received many names in the literature, such as ''post-transition metals'', ''poor metals'', ''other metals'', ''p-block metals'' and ''chemically weak metals''; none have been recommended by IUPAC. The most common name, ''post-transition metals'', is generally used in this article. Depending on where the adjacent sets of transition metals and metalloids are judged to begin and end, there are at least five competing proposals for which elements to count as post-transition metals: the three most common contain six, ten and thirteen elements, respectively (see image). All proposals include gallium, indium, tin, thallium, lead, and bismuth. Physically, these metals are soft (or brittle), have poor mechanical strength, and usually have melting points lower than those of the transition metals. Being close to the metal-nonmetal border, their crystallin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cownose Ray
The cownose ray (''Rhinoptera bonasus'') is a species of Batoidea found throughout a large part of the western Atlantic and Caribbean, from New England, United States to southern Brazil (the East Atlantic populations are now generally considered a separate species, the Lusitanian cownose ray (''R. marginata'')). Male rays often reach about 2 and 1/2 feet in width. Females typically reach about 3 feet in width. However, there have been reports of rays up to 7 feet in width. Sizes change depending on the geographical range. Females will usually grow larger than males, allowing for larger offspring. These rays also belong to the order Myliobatiformes, a group that is shared by bat rays, manta rays, and eagle rays. In 2019, the species was listed as vulnerable on the IUCN Red List. Taxonomy The genus name '' Rhinoptera'' is named for the Ancient Greek words for nose (''rhinos'') and wing (''pteron''). The species name ''bonasus'' comes from the Ancient Greek for bison (''bonasos' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Of Maine
The Gulf of Maine is a large gulf of the Atlantic Ocean on the east coast of North America. It is bounded by Cape Cod at the eastern tip of Massachusetts in the southwest and by Cape Sable Island at the southern tip of Nova Scotia in the northeast. The gulf includes the entire coastlines of the U.S. states of New Hampshire and Maine, as well as Massachusetts north of Cape Cod, and the southern and western coastlines of the provinces and territories of Canada, Canadian provinces of New Brunswick and Nova Scotia, respectively. The gulf was named for the adjoining English colonial Province of Maine, which was in turn likely named by early explorers after the Maine (province), province of Maine in France. Massachusetts Bay, Penobscot Bay, Passamaquoddy Bay, and the Bay of Fundy are all arms of the Gulf of Maine. Geography and hydrography The Gulf of Maine is a roughly rectangular depression with a surface area of around , enclosed to the west and north by the North American mainland ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homer, Alaska
Homer ( Dena'ina: ''Tuggeght'') is a city in Kenai Peninsula Borough in the U.S. state of Alaska. It is southwest of Anchorage. According to the 2020 Census, the population is 5,522, up from 5,003 in 2010. Long known as the "Halibut Fishing Capital of the World", Homer is also nicknamed "the end of the road", and more recently, "the cosmic hamlet by the sea". Geography Homer is located at 59°38'35" North, 151°31'33" West (59.643059, −151.525900). The only road into Homer is the Sterling Highway. Homer is on the shore of Kachemak Bay on the southwest side of the Kenai Peninsula. Its distinguishing feature is the Homer Spit, a narrow long gravel bar that extends into the bay, on which is located the Homer Harbor. Much of the coastline, as well as the Homer Spit, sank dramatically during the Good Friday earthquake in March 1964. After the earthquake, very little vegetation was able to survive on the Homer Spit. The town has a total area of , of which are land and ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preference Tests (animals)
A preference test is an experiment in which animals are allowed free access to multiple environments which differ in one or more ways. Various aspects of the animal's behaviour can be measured with respect to the alternative environments, such as latency and frequency of entry, duration of time spent, range of activities observed, or relative consumption of a goal object in the environment. These measures can be recorded either by the experimenter or by motion detecting software. Strength of preference can be inferred by the magnitude of the difference in the response, but see "Advantages and disadvantages" below. Statistical testing is used to determine whether observed differences in such measures support the conclusion that preference or aversion has occurred. Prior to testing, the animals are usually given the opportunity to explore the environments to habituate and reduce the effects of novelty. Preference tests can be used to test for preferences of only one characterist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiny Dogfish
The spiny dogfish (''Squalus acanthias''), spurdog, mud shark, or piked dogfish is one of the best known species of the Squalidae (dogfish) family (biology), family of sharks, which is part of the Squaliformes order. While these common names may apply to several species, ''Squalus acanthias'' is distinguished by two spines (one wikt:anterior, anterior to each dorsal fin) and no anal fin. It lives in shallow waters and further offshore in most parts of the world, especially in temperate waters. Those in the northern Pacific Ocean were reevaluated in 2010 and found to constitute a separate species, now called the Pacific spiny dogfish, Pacific spiny dogfish (''Squalus suckleyi''). Description and behaviour The spiny dogfish has dorsal fins, no anal fin, and white spots along its back. The Caudal (anatomical term), caudal fin has asymmetrical lobes, forming a heterocercal tail. The species name ''acanthias'' refers to the shark's two spines. These are used defensively. If captured ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mischmetal
Mischmetal (from german: Mischmetall – "mixed metal") is an alloy of rare-earth elements. It is also called cerium mischmetal, or rare-earth mischmetal. A typical composition includes approximately 55% cerium, 25% lanthanum, and 15~18% neodymium, with traces of other rare earth metals; it contains 95% lanthanides and 5% iron. Its most common use is in the pyrophoric ferrocerium "flint" ignition device of many lighters and torches, although an alloy of only rare-earth elements would be too soft to give good sparks. For this purpose, it is blended with iron oxide and magnesium oxide to form a harder material known as ferrocerium. In chemical formulae it is commonly abbreviated as Mm, e.g. MmNi5. History Carl Auer von Welsbach was the discoverer of neodymium and praseodymium, and co-discoverer of lutetium. He was also the inventor of the gas mantle (using thorium) and of the rare-earth industry. After extracting thorium from monazite sand, many lanth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corrosion
Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and preventing corrosion. In the most common use of the word, this means electrochemical oxidation of metal in reaction with an oxidant such as oxygen, hydrogen or hydroxide. Rusting, the formation of iron oxides, is a well-known example of electrochemical corrosion. This type of damage typically produces oxide(s) or salt(s) of the original metal and results in a distinctive orange colouration. Corrosion can also occur in materials other than metals, such as ceramics or polymers, although in this context, the term "degradation" is more common. Corrosion degrades the useful properties of materials and structures including strength, appearance and permeability to liquids and gases. Many structural ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrolysis
Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis is the cleavage of biomolecules where a water molecule is consumed to effect the separation of a larger molecule into component parts. When a carbohydrate is broken into its component sugar molecules by hydrolysis (e.g., sucrose being broken down into glucose and fructose), this is recognized as saccharification. Hydrolysis reactions can be the reverse of a condensation reaction in which two molecules join into a larger one and eject a water molecule. Thus hydrolysis adds water to break down, whereas condensation builds up by removing water. Types Usually hydrolysis is a chemical process in which a molecule of water is added to a substance. Sometimes this addition causes both the substance and w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen
Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, and highly combustible. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all normal matter.However, most of the universe's mass is not in the form of baryons or chemical elements. See dark matter and dark energy. Stars such as the Sun are mainly composed of hydrogen in the plasma state. Most of the hydrogen on Earth exists in molecular forms such as water and organic compounds. For the most common isotope of hydrogen (symbol 1H) each atom has one proton, one electron, and no neutrons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reducing Agents
In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ). Examples of substances that are commonly reducing agents include the Earth metals, formic acid, oxalic acid, and sulfite compounds. In their pre-reaction states, reducers have extra electrons (that is, they are by themselves reduced) and oxidizers lack electrons (that is, they are by themselves oxidized). This is commonly expressed in terms of their oxidation states. An agent's oxidation state describes its degree of loss of electrons, where the higher the oxidation state then the fewer electrons it has. So initially, prior to the reaction, a reducing agent is typically in one of its lower possible oxidation states; its oxidation state increases during the reaction while that of the oxidizer decreases. Thus in a redox reaction, the agent whose oxidation state increases, that "loses/ donates electrons", that "is oxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
