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Dry Glue
Dry glue is an adhesion product based upon the adaptations of geckos' feet that allow them to climb sheer surfaces such as vertical glass. Synthetic equivalents use carbon nanotubes as synthetic setae on reusable adhesive patches. Background A gecko can hang on a glass surface using only one toe. This ability is attributed to van der Waals force, although a more recent study suggests that water molecules of roughly monolayer thickness (present on virtually all natural surfaces) also play a role. Developments In 2007, researchers from the University of Akron and Rensselaer Polytechnic Institute announced they had developed a form of flexible, reusable gecko tape using carbon nanotubes to create microscopic synthetic setae and spatulae capable of supporting a shear stress of 32 N/ cm2, which is four times the strength of a gecko's foot. In 2008 researchers from the University of Dayton reported a gecko glue capable of supporting 100N/cm2, ten times the strength generated by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adhesion
Adhesion is the tendency of dissimilar particles or surfaces to cling to one another ( cohesion refers to the tendency of similar or identical particles/surfaces to cling to one another). The forces that cause adhesion and cohesion can be divided into several types. The intermolecular forces responsible for the function of various kinds of stickers and sticky tape fall into the categories of chemical adhesion, dispersive adhesion, and diffusive adhesion. In addition to the cumulative magnitudes of these intermolecular forces, there are also certain emergent mechanical effects. Surface energy Surface energy is conventionally defined as the work that is required to build an area of a particular surface. Another way to view the surface energy is to relate it to the work required to cleave a bulk sample, creating two surfaces. If the new surfaces are identical, the surface energy γ of each surface is equal to half the work of cleavage, W: γ = (1/2)W11. If the surfac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shear Stress
Shear stress, often denoted by (Greek: tau), is the component of stress coplanar with a material cross section. It arises from the shear force, the component of force vector parallel to the material cross section. ''Normal stress'', on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts. General shear stress The formula to calculate average shear stress is force per unit area.: : \tau = , where: : = the shear stress; : = the force applied; : = the cross-sectional area of material with area parallel to the applied force vector. Other forms Wall shear stress Wall shear stress expresses the retarding force (per unit area) from a wall in the layers of a fluid flowing next to the wall. It is defined as: \tau_w:=\mu\left(\frac\right)_ Where \mu is the dynamic viscosity, u the flow velocity and y the distance from the wall. It is used, for example, in the description of arterial blood flow in which case which ther ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gecko Tape
Nano tape, also called gecko tape; marketed under the name Alien Tape, is a synthetic adhesive tape consisting of arrays of carbon nanotubes transferred onto a backing material of flexible polymer tape. These arrays are called synthetic setae and mimic the nanostructures found on the toes of a gecko; this is an example of biomimicry. The adhesion is achieved not with chemical adhesives, but via van der Waals forces, which are weak electric forces generated between two atoms or molecules that are very close to each other. Explanation Geckos show a remarkable ability to climb smooth vertical surfaces at high speeds, exhibiting both strong attachment and easy rapid removal, or shear adhesion, of their feet. On a gecko's foot, micrometer-sized elastic hairs called setae are split into nanometer-sized structures called spatulas. The shear adhesion is achieved by forming and breaking van der Waals forces between these microscopic structures and the substrate. Nano tapes mimic th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gecko Adhesion
Geckos are small, mostly carnivorous lizards that have a wide distribution, found on every continent except Antarctica. Belonging to the infraorder Gekkota, geckos are found in warm climates throughout the world. They range from . Geckos are unique among lizards for their vocalisations, which differ from species to species. Most geckos in the family Gekkonidae use chirping or clicking sounds in their social interactions. Tokay geckos (''Gekko gecko'') are known for their loud mating calls, and some other species are capable of making hissing noises when alarmed or threatened. They are the most species-rich group of lizards, with about 1,500 different species worldwide. All geckos, except species in the family Eublepharidae lack eyelids; instead, the outer surface of the eyeball has a transparent membrane, the cornea. They have a fixed lens within each iris that enlarges in darkness to let in more light. Since they cannot blink, species without eyelids generally lick the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celsius
The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference or range between two temperatures. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale in 1742. Before being renamed in 1948 to honour Anders Celsius, the unit was called ''centigrade'', from the Latin ''centum'', which means 100, and ''gradus'', which means steps. Most major countries use this scale; the other major scale, Fahrenheit, is still used in the United States, some island territories, and Liberia. The Kelvin scale is of use in the sciences, with representing absolute zero. Since 1743 the Celsius scale has been based on 0 °C for the freezing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitto Denko
is a Japanese company that produces tapes, vinyl, LCDs, insulation, and several other products. It was founded in Osaki, Tokyo in 1918 to produce electrical insulation and it survived World War II, despite the destruction of its central offices which have since moved to Osaka. Nitto is a member of the Mitsubishi UFJ Financial Group (MUFG) keiretsu. History *1918 Nitto Electric Industrial Company, Limited forms in Ohsaki, Tokyo, to produce electrical insulating materials in Japan. *1924 Introduces electrical insulating varnishes. *1941 Ibaraki Plant begins operation. *1945 Head Office in Osaki, Tokyo, destroyed by air raids. *1946 **Head Office is relocated to Ibaraki, Osaka ; **Begins production of Black Tape. *1949 **Opens Osaka and Tokyo Branch Offices ; **Begins production of anticorrosion tapes. *1951 Produces first plastic tapes in Japan. *1957 Begins production of electrical insulating casting and molding products. *1959 Suita Plant begins operation. *1961 **Opens first o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DARPA
The Defense Advanced Research Projects Agency (DARPA) is a research and development agency of the United States Department of Defense responsible for the development of emerging technologies for use by the military. Originally known as the Advanced Research Projects Agency (ARPA), the agency was created on February 7, 1958, by President Dwight D. Eisenhower in response to the Soviet Union, Soviet launching of Sputnik 1 in 1957. By collaborating with academia, industry, and government partners, DARPA formulates and executes research and development projects to expand the frontiers of technology and science, often beyond immediate U.S. military requirements.Dwight D. Eisenhower and Science & Technology, (2008). Dwight D. Eisenhower Memorial CommissionSource ''The Economist'' has called DARPA the agency "that shaped the modern world," and pointed out that "Moderna COVID-19 vaccine, Moderna's COVID-19 vaccine sits alongside weather satellites, Global Positioning System, GPS, Unmann ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Dayton
The University of Dayton (UD) is a private, Catholic research university in Dayton, Ohio. Founded in 1850 by the Society of Mary, it is one of three Marianist universities in the nation and the second-largest private university in Ohio. The university's campus is in the city's southern portion and spans 388 acres on both sides of the Great Miami River. The campus is noted for the Immaculate Conception Chapel and the University of Dayton Arena. In the fall of 2020, the university enrolled 11,347 full-time students from a variety of religious, ethnic, and geographic backgrounds. It offers more than 80 academic programs in arts and sciences, business administration, education and health sciences, engineering and law. In 2009, UD offered what it believes to be one of the first undergraduate degree programs in human rights. It is classified among "R2: Doctoral Universities – High research activity". The university's notable alumni include: Ohio Lieutenant Governor Jon Husted; humo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metre
The metre (British spelling) or meter (American spelling; see spelling differences) (from the French unit , from the Greek noun , "measure"), symbol m, is the primary unit of length in the International System of Units (SI), though its prefixed forms are also used relatively frequently. The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately km. In 1799, the metre was redefined in terms of a prototype metre bar (the actual bar used was changed in 1889). In 1960, the metre was redefined in terms of a certain number of wavelengths of a certain emission line of krypton-86. The current definition was adopted in 1983 and modified slightly in 2002 to clarify that the metre is a measure of proper length. From 1983 until 2019, the metre was formally defined as the length of the path travelled by light in a vacuum in of a second. After the 2019 redefi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newton (unit)
The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as 1 kg⋅m/s, the force which gives a mass of 1 kilogram an acceleration of 1 metre per second per second. It is named after Isaac Newton in recognition of his work on classical mechanics, specifically Newton's second law of motion. Definition A newton is defined as 1 kg⋅m/s (it is a derived unit which is defined in terms of the SI base units). One newton is therefore the force needed to accelerate one kilogram of mass at the rate of one metre per second squared in the direction of the applied force. The units "metre per second squared" can be understood as measuring a rate of change in velocity per unit of time, i.e. an increase in velocity by 1 metre per second every second. In 1946, Conférence Générale des Poids et Mesures (CGPM) Resolution 2 standardized the unit of force in the MKS system of units to be the amount needed to accelerate 1 kilogram of mass at the rate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spatula
A spatula is a broad, flat, flexible blade used to mix, spread and lift material including foods, drugs, plaster and paints. In medical applications, "spatula" may also be used synonymously with tongue depressor. The word ''spatula'' derives from the Latin word for a flat piece of wood or splint, a diminutive form of the Latin , meaning 'broadsword', and hence can also refer to a tongue depressor. The words ''spade'' (digging tool) and ''spathe'' are similarly derived. The word ''spatula'' has been used in English since 1525. Use Spatulas are usually used to scrape within the contours of a mixing bowl or to level off the top of a dry mixing cup. Kitchen use American English In American English, ''spatula'' refers broadly to a number of broad, flat utensils. The word commonly refers to a turner or flipper (known in British English as a ''fish slice''), used to lift and flip food items during cooking, such as pancakes and fillets. The blades on these are usually made of met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adaptation
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic trait or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection. Historically, adaptation has been described from the time of the ancient Greek philosophers such as Empedocles and Aristotle. In 18th and 19th century natural theology, adaptation was taken as evidence for the existence of a deity. Charles Darwin proposed instead that it was explained by natural selection. Adaptation is related to biological fitness, which governs the rate of evolution as measured by change in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations that interlock with those of the oth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
