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Washburn's Equation
In physics, Washburn's equation describes capillary flow in a bundle of parallel cylindrical tubes; it is extended with some issues also to imbibition into porous materials. The equation is named after Edward Wight Washburn; also known as Lucas–Washburn equation, considering that Richard Lucas wrote a similar paper three years earlier, or the Bell-Cameron-Lucas-Washburn equation, considering J.M. Bell and F.K. Cameron's discovery of the form of the equation in 1906. Derivation In its most general form the Lucas Washburn equation describes the penetration length (L) of a liquid into a capillary pore or tube with time t as L=(Dt)^, where D is a simplified diffusion coefficient. This relationship, which holds true for a variety of situations, captures the essence of Lucas and Washburn's equation and shows that capillary penetration and fluid transport through porous structures exhibit diffusive behaviour akin to that which occurs in numerous physical and chemical systems. The dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physics
Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regular succession of events." Physics is one of the most fundamental scientific disciplines, with its main goal being to understand how the universe behaves. "Physics is one of the most fundamental of the sciences. Scientists of all disciplines use the ideas of physics, including chemists who study the structure of molecules, paleontologists who try to reconstruct how dinosaurs walked, and climatologists who study how human activities affect the atmosphere and oceans. Physics is also the foundation of all engineering and technology. No engineer could design a flat-screen TV, an interplanetary spacecraft, or even a better mousetrap without first understanding the basic laws of physic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wetting
Wetting is the ability of a liquid to maintain contact with a solid surface, resulting from intermolecular interactions when the two are brought together. This happens in presence of a gaseous phase or another liquid phase not miscible with the first one. The degree of wetting (wettability) is determined by a force balance between adhesive and cohesive forces. Wetting is important in the bonding or adherence of two materials. Wetting and the surface forces that control wetting are also responsible for other related effects, including capillary effects. There are two types of wetting: non-reactive wetting and reactive wetting. Wetting deals with three phases of matter: gas, liquid, and solid. It is now a center of attention in nanotechnology and nanoscience studies due to the advent of many nanomaterials in the past two decades (e.g. graphene, Carbon nano tube, carbon nanotube, boron nitride nanomesh). Explanation Adhesive forces between a liquid and solid cause a liqu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porosimetry
Porosimetry is an analytical technique used to determine various quantifiable aspects of a material's porous structure, such as pore diameter, total pore volume, surface area, and bulk and absolute densities. The technique involves the intrusion of a non-wetting liquid (often mercury) at high pressure into a material through the use of a porosimeter. The pore size can be determined based on the external pressure needed to force the liquid into a pore against the opposing force of the liquid's surface tension. A force balance equation known as Washburn's equation for the above material having cylindrical pores is given as: :P_L - P_G = -\frac :P_ = pressure of liquid :P_ = pressure of gas :\sigma = surface tension of liquid :\theta = contact angle of intrusion liquid :D_ = pore diameter Since the technique is usually performed within a vacuum, the initial gas pressure is zero. The contact angle of mercury with most solids is between 135° and 142°, so an average of 140 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lateral Flow Test
A lateral flow test (LFT), is an assay also known as a lateral flow device (LFD), lateral flow immunochromatographic assay, or rapid test. It is a simple device intended to detect the presence of a target substance in a liquid sample without the need for specialized and costly equipment. LFTs are widely used in medical diagnostics in the home, at the point of care, and in the laboratory. For instance, the home pregnancy test is an LFT that detects a specific hormone. These tests are simple and economical and generally show results in around five to thirty minutes. Many lab-based applications increase the sensitivity of simple LFTs by employing additional dedicated equipment. Because the target substance is often a biological antigen, many lateral flow tests are rapid antigen tests (RAT or ART). LFTs operate on the same principles of affinity chromatography as the enzyme-linked immunosorbent assays (ELISA). In essence, these tests run the liquid sample along the surface of a pad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dunk (biscuit)
To dunk or to dip a biscuit or some other food, usually baked goods, means to submerge it into a drink, especially tea, coffee, or milk. Dunking releases more flavour from confections by dissolving the sugars, while also softening their texture. Dunking can be used to melt chocolate on biscuits to create a richer flavour. Dunking is a popular way of enjoying biscuits in many countries. A popular form of dunking in Australia is the " Tim Tam Slam", also known as 'tea sucking'. The physics of dunking is driven by the porosity of the biscuit and the surface tension of the beverage. A biscuit is porous and, when dunked, capillary action draws the liquid into the interstices between the crumbs. Dunking is first reported with ancient Romans softening their hard unleavened wafers (Latin: ''bis coctum'' – "twice baked") in wine. Modern day dunking has its roots in naval history when, in the 16th century, biscuits known as " hard tack" were on board Royal Navy ships, which were so ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Len Fisher
Leonard Ross Fisher (born 1942) is an Australian physicist, and visiting senior research fellow at the University of Bristol, UK. He is known for his research into everyday topics, such as the optimal way to dunk a biscuit, and the optimum use of cheese in a cheese sandwich. Education Fisher received a BSc in chemistry and pure mathematics, and an MSc in radiation chemistry from the University of Sydney. He has a PhD in physics of surfaces from the University of New South Wales. Career Fisher has been a visiting senior research fellow in the school of physics at the University of Bristol since 1992. Research In 1998, Fisher published a study on the optimal way to dunk a biscuit. The study concluded that 10 times more flavour is released from a biscuit if it has first been dunked in a hot drink. This research was funded by McVities. In 2000, Fisher studied the absorption of gravy by a roast dinner. He found that 700,000 litres of gravy is wasted every week in the UK wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ig Nobel Prize
The Ig Nobel Prize ( ) is a satiric prize awarded annually since 1991 to celebrate ten unusual or trivial achievements in scientific research. Its aim is to "honor achievements that first make people laugh, and then make them think." The name of the award is a pun on the Nobel Prize, which it parodies, and on the word '' ignoble'' ("not noble"). Organized by the scientific humor magazine, '' Annals of Improbable Research'' (AIR), the Ig Nobel Prizes are presented by Nobel laureates in a ceremony at the Sanders Theater, Harvard University, and are followed by the winners' public lectures at the Massachusetts Institute of Technology. History The Ig Nobels were created in 1991 by Marc Abrahams, editor and co-founder of the '' Annals of Improbable Research'', a former editor-in-chief of the ''Journal of Irreproducible Results'' who has been master of ceremonies at all awards ceremonies. Awards were presented at that time for discoveries "that cannot, or should not, be reproduce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of phenomena, and usually frame their understanding in mathematical terms. Physicists work across a wide range of research fields, spanning all length scales: from sub-atomic and particle physics, through biological physics, to cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: experimental physicists who specialize in the observation of natural phenomena and the development and analysis of experiments, and theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their knowledge towards solving practical problems or to developing new technologies (also known as app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bosanquet Equation
In the theory of capillarity, Bosanquet equation is an improved modification of the simpler Lucas–Washburn theory for the motion of a liquid in a thin capillary tube or a porous material that can be approximated as a large collection of capillaries. In the Lucas–Washburn model, the inertia of the fluid is ignored, leading to the assumption that flow is continuous under constant viscous laminar Poiseuille flow conditions without considering the effects of mass transport undergoing acceleration occurring at the start of flow and at points of changing internal capillary geometry. The Bosanquet equation is a differential equation that is second-order in the time derivative, similar to Newton's Second Law, and therefore takes into account the fluid inertia. Equations of motion, like the Washburn's equation, that attempt to explain a velocity (instead of acceleration) as proportional to a driving force are often described with the term ''Aristotelian mechanics''.Arthur Stinner, "The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inertia
Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law of motion. After some other definitions, Newton states in his first law of motion: The word "perseveres" is a direct translation from Newton's Latin. Other, less forceful terms such as "to continue" or "to remain" are commonly found in modern textbooks. The modern use follows from some changes in Newton's original mechanics (as stated in the ''Principia'') made by Euler, d'Alembert, and other Cartesians. The term inertia comes from the Latin word ''iners'', meaning idle, sluggish. The term inertia may also refer to the resistance of any physical object to a change in its velocity. This includes changes to the object's speed or direction of motion. An aspect of this property is the tendency of objects to keep moving in a straight lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Equation
In mathematics, a differential equation is an equation that relates one or more unknown functions and their derivatives. In applications, the functions generally represent physical quantities, the derivatives represent their rates of change, and the differential equation defines a relationship between the two. Such relations are common; therefore, differential equations play a prominent role in many disciplines including engineering, physics, economics, and biology. Mainly the study of differential equations consists of the study of their solutions (the set of functions that satisfy each equation), and of the properties of their solutions. Only the simplest differential equations are solvable by explicit formulas; however, many properties of solutions of a given differential equation may be determined without computing them exactly. Often when a closed-form expression for the solutions is not available, solutions may be approximated numerically using computers. The theory of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid is forced through a tube, it flows more quickly near the tube's axis than near its walls. Experiments show that some stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion. For a tube with a constant rate of flow, the strength of the compensating force is proportional to the fluid's viscosity. In general, viscosity depends on a fluid's state, such as its temperature, pressure, and rate of deformation. However, the dependence on some of these properties is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
