The Influence of Nano-Metamaterials on Facade and Appearance of Buildings
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Archive of SID The influence of nano-metamaterials on facade and appearance of buildings First Author: Tiam Afshin Affiliation: Bachelor student in Islamic Azad University of Najafabad Email: [email protected] Second Author: Babak Moradian Affiliation: Professor of Islamic Azad University of Najafabad Email: [email protected] Third Author: Nader Maleki Affiliation: Professor of Amin University of Foladshahr Email: [email protected] Abstract The metamaterials are man-made and created by artificial substances , that can not be found in nature. The first implication of nano metamaterials refers to artificial dielectrics and electronic substances. The important trait of their function , is the manipulation of lights such a circular way around the object that can make them invisible . The present research is following the way to answer these questions , Can these materials be used for improving the operation of facades? Do these materials have any function in architecture or not ? or What kind of revolution may be appeared in architecture by these materials? According to physicians researches about metamaterials , has been indicated that ,these substances have an ability to manipulate the lights then disappear themselves . It is axiomatic that , this trait can be used in many fields specially architecture , if they can be controlled and be considered as an increasing thermal capacity and amplification of acoustic feature. By these characteristics, they can have a suitable role in buildings. Keywords: nano metamaterials – building’s form and facade – invisible elevation www.SID.ir Archive of SID Introduction Nanotechnology, the buzzword today’s material scientist is “metamaterials”. These substances are tiny engineered structures from exciting composite that are used to manipulate light, sound and radiowaves .The history of metamaterials begins with artificial dielectrics in microwave engineering as it developed just after world war II. Yet , there are seminal explorations of artificial materials for manipulating electromagnetic waves at the end of the 19th century (21) . Hence , the history of metamaterials is essentially a history of developing certain types of manufactured materials, which interact at radio frequency , microwave ,and later optical frequencies , and one of the key application for metamaterials lies in their ability to distortion light to be disappeared . (10) In this context , metamaterials can be defined as unreal substances but with electromagnetic properties that are inaccessible in nature or are difficult to obtain . Perhaps the most representative metamaterial is the so called “left-handed” one with is characterized by a simultaneously negative permittivity and permeability , thus implying a negative index of refraction these hypothetical media were systematically studied by Victor Veselago in 1960s (31) . To access these unusual material parameters , the constituent unit cells need to be resonated ( but still electrically small) which leads to dispersion . consequently , unlike Kock’s artificial dielectrics , metamaterials are usually dispersive in nature (8) . The solution to the problem of realizing such a left-handed or negative- index (NRI) medium was solved three decades later by Shelby ,Smith and Schultz (25) . The former century has been the age of artificial materials . One materials that stands out in this regard , is the semiconductor . Revolution in the electronics industry in the last century was made possible , by the ability of semiconductor to microscopically manipulate the flow of electrons . Further advancement in the field prompted scientists to suggest that , the new millennium will be the age of photonic in which artificial materials will be synthesized to microscopically manipulate the flow of electromagnetic waves . One of these will be Left Handed (LHM) materials . Such as new man-made materials often referred to as Negative Index Media (NIM) Backward Wave Media (BWM) , negative (DNG) metamaterial .Fig.1 (9) . Figure 1: Orientation of the electric E , magnetic H , power P , and phase K vector Then , In which research has attracted tremendous attention in the past few years because of their electromagnetic properties and ability to guide evanescent field , are significantly different from those of Right Handed Materials (RHMs) . They exhibit simultaneous negative values for permittivity , ε , and permeability , µ , in an overlapping frequency region , science the values are derived from the effect of the composite medium system as a whole ; these are defined as effective permittivity ε and permeability µ . Real value are derived to denote the value of negative index of refraction and www.SID.ir Archive of SID wave vectors . This means that in practice losses will occur for given medium used to transmit electromagnetic radiation such as microwave or infrared frequencies , or visible light for example real values describe , either the amplitude or the intensity of a transmitted wave relative to an ancient wave ; while ignoring the negligible loss values (27,26) . Figure 2: Photograph of the left handed material sample Figure 3: Negative vs Positive refraction The structure that was used consisted of an array of strip wire to synthesize a negative permittivity and split-ring resonators (capacitively loaded loops ) to synthesize negative permeability ,as shown in Fig.2-3 . The use of an array of inductive wires to synthesize artificial dielectrics with plasma-like behavior was previously reported by Walter Rotman (23) ,(although Rotman never explored the ε < 0 region) and independently by John Pendry (19) . In a slab of conventional material , with an ordinary refractive index-a Right Handed Material- the wave front is transmitted away from the source. In a LHM the front travels toward the source. Although the magnitude and the direction of the flow of energy essentially remains the same in both materials , the impedance of these two materials match . The left-handed property causes to disappear objects and etc… (5,39) . Figure 4 , shows how does metamaterials disappear , according to the researches and theories and investigations in this field, this is the best sample of their implication. Figure 4: This graphic representation shows how tree active source cloak an incoming circular wave, creating a quiet zone for the object to be cloaked. This is just for one frequency . Credit : Fernando Vasquez .University of Utah (National science foundation) After reviewing their features and structures , it was possible to predict that , these substances can be used in many fields, then it leaded many persons to research .Viktor Veselago the physician from Russia , by presenting an unbelievable article about , the existent material with negative simultaneous µ and ε , could present the new subject from 1967 (33) . After viktor presentation , that had been www.SID.ir Archive of SID spent about 30 years until the first material LH , had been found experimentally. Smith and Colleagues in California and San Diego university suggested that , this was not mundane substance rather than ; it was an effective artificial structure of homogenous (28) . James Clerk Maxwell’s question predicting the existence of electromagnetic radiation propagating at the speed of light were made public in 1865 in 1888 Hertz ; had demonstrated the generation of electromagnetic waves , and that their properties were similar to those of light (24) . Before the start of twenty century , many of the concept now familiar in microwave had been developed . The list include the cylindrical parabolic reflector , dielectric lens , microwave absorbers , the cavity radiator , the radiating iris and the pyramidal electromagnetic horn . Round square and rectangular wave guides were used , with experimental development anticipating by several years Rayleigh’s 1896 theoretical solution (13) In periodic after all researches, magnetic structure has received extensive attention . One of the first attempts to study the spin wave propagation in periodic systems , was made by Elachi (6) . Recently , an active area of research devoted to the study of metamaterial properties of magnetic crystals is born (11,1) . A comprehensive review of artificial dielectrics , including a rigorous mathematical treatment from that era can be found (7) . Moreover , it is worth mentioning some relevant early work on effective media , including that of Bose who in 1898 used man-made twisted fibers (jute) to rotate the polarization of electromagnetic waves , thus emulating naturally occurring chiral media such as sugar (4) . In a related effort , Lindman in 1914 studied artificial chiral media formed by an ensemble of small wire helices (12) . A new similar investigation was performed by taking as a magnetic material antiferromagnetic (22) . Secondly , a study of the effective properties of a one-dimensional (1D) magnetic crystal consisting of a periodically layered cylindrical nanowire was made and effective magnetic quantities were introduced (34,35) . The calculation of magnetic mode spatial profiles at the edge of BZs (wave vectors) and their characterization by means of the effective wavelength and small wave vector could suggest, an experiment similar to the one performed for mapping vortex-state modes in isolated disks of micrometric size (15)or in 2D arrays of saturated magnetic nanoelements. Acoustic In the present article ,an attempt has been tried to negotiate about the characterizations of metamaterials and even their important applications