Electromagnetic pulse (EMP) protective building materials and method for manufacture

Abstract

A novel building material provides EMP protection as well as sound proofing and thermal insulation. The invention facilitates the production of a low mass, composite EMP-Drywall that eliminates an electromagnetic pulse, acts as a sound barrier, and provides thermal insulation. Alternatively, an EMP-Plaster consisting of layers of plaster-like materials can be applied by trowel or similar method to curved and flat surfaces. The EMP-Plaster eliminates an electromagnetic pulse, acts as a sound barrier, and provides thermal insulation.

Description

[0001]Docket No.: 0206-018P1PCT ELECTROMAGNETIC PULSE (EMP) PROTECTIVE BUILDING MATERIALS AND METHOD FOR MANUFACTURE David Charles Lynch RELATED CASES The present application claims the benefit of co-pending U.S. Patent Application Serial No.18 / 747,975, filed on June 19, 2024 by the same inventor and co-pending U.S. Provisional Application No.63 / 525,124, filed on July 5, 2023 by the same inventor and entitled “Electromagnetic Pulse (EMP) Protection: EMP-Drywall and EMP-Plaster”, which are both incorporated herein by reference in their entireties. BACKGROUND OF THE INVENTION Field of the Invention This invention relates generally to hollow spheres, and more particularly to the production and use of hollow spheres. Even more particularly, this invention relates to the production of building materials utilizing hollow spheres. Description of the Background Art An electromagnetic pulse (EMP) is a brief burst of electromagnetic energy. In the Executive Summary of the National Cybersecurity and Communications Integration Center’s report entitled “Electromagnetic Pulse (EMP) Protection and Resilience Guidelines for Critical Infrastructure and Equipment” the authors of that report identify 4 categories of EMPs. The four categories of EMPs include: 1. “[N]aturally occurring geomagnetic disturbance (GMD), also referred to as space weather,” an example being a solar flare; 2. “High-altitude EMP (HEMP), from a nuclear detonation typically occurring 15 or more miles above the Earth’s surface”; Docket No.: 0206-018P1PCT 3. “Source Region EMP (SREMP), created when a nuclear weapon detonates at lower altitudes, especially when the detonation is at or near the surface of the earth”; and 4. “Intentional Electromagnetic Interference (IEMI), from nearby sources such as an Electromagnetic (EM) weapon (also known as a Radio Frequency (RF) weapon (RFW))”. In that report the authors recommend four levels of protection against an EMP. The two highest levels of security, Levels 3 and 4, provide specific guidelines as to protection from both acoustic energy and an electromagnetic pulse. The guidelines include: Level 3 – “Shielding should be 30+ dB of protection through 10 GHz”; and Level 4 – “Use Military EMP Standards (like MIL- STD-188-125-1 and MIL-HDBK-423), and 80+ dB hardening through 10 GHz”. The 1859 “Carrington Event” is the most intense geomagnetic storm in recorded history, creating strong auroral displays that were reported globally and disrupted the most advanced communication of that era, the telegraph. The Sun’s coronal mass ejection (CME) through interaction with the Earth’s magnetosphere produced sparking and even fires in multiple telegraph stations. Today that Event would cause widespread electrical disruptions, blackouts, and damage due to extended outages of the electrical power grid, at a cost of US$698 billion to US$2.6 trillion (in 2021 dollars). Less severe CME events occurred in 1921 and 1960, when widespread radio disruption occurred. The March 1989 CME event took out power across large sections of Quebec. In July 2012, a “Carrington-Class Event” narrowly missed Earth while other earlier events struck our planet. Through carbon dating and analysis of ice cores, major CME strikes are known to have occurred during the years 774–775 CE and during 993–994 CE. The 774-775 event was 10 or more times the magnitude of the “Carrington Event.” The Earth is on the verge of reaching the maximum of the Sun’s 25th recorded solar cycle, which will occur between November 2024 and March 2026. Sunspot data indicates the upcoming maximum will produce an increase in the number of solar flares (also referred to as CME events). Docket No.: 0206-018P1PCT During the earliest days of nuclear weapons development, it was known that testing could produce an electromagnetic pulse, a fact the British experienced in 1952- 1953 by, unlike the Americans, leaving their instruments on during testing. The first attempt to measure EMP with an atomic bomb explosion took place with the Hartack I series in 1958. The pulse exceeded the instrument’s range of detection. Sound transmission class (STC) is an integer rating of how well a building partition attenuates airborne sound and is expressed on a scale of 0 to 100. An STC rating of 100 means complete sound proofing measured over multiple sound frequencies between 125 Hz (base levels) to 4,000 Hz (treble levels). For the human ear a STC rating of 25 is no soundproofing, whereas a value of 65 is considered complete sound proofing. An STC rating roughly reflects the decibel reduction of noise, thus, a decibel reduction rated at 80+ can be achieved by an increase in the STC rating of approximately 80. Sound attenuation improves with increased mass that absorbs sound. That has been the classic approach to reducing noise. That fact is confirmed through STC rating of materials as indicated by the numbers below. STC 27 - Single pane glass window STC 46 - 6" hollow CMU (concrete masonry unit) STC 48 - 8" hollow CMU (concrete masonry unit) STC 50 - 10" hollow CMU (concrete masonry unit) STC 64 - 8" hollow CMU (concrete masonry unit) with 3" steel studs, fiberglass insulation, and 1 / 2" drywall on each side However, sound can be reduced by an opposite approach. Sound is not transmitted through a vacuum. A classic proof of that can be found on the Internet. Students in physics classes experience what happens to sound from an electric bell when hung inside a bell jar by thin electric wires and the pressure is reduced. For sound to be transmitted it requires mass, without mass, as in a vacuum, it cannot be transmitted. A perfect vacuum will have an STC rating of 100. A Faraday cage consists of a mesh of electrical conducting material forming a complete and grounded cage surrounding the instruments and equipment to be protected. The cage works because an external electrical field causes the conducting electrons within the cage's conducting material to be distributed so that they cancel the field's effect upon entering the cage's interior. A negative EMP repels free electrons in the cage material, Docket No.: 0206-018P1PCT leaving an uncompensated positive charge that neutralizes the negative pulse. The opposite occurs with a positive EMP. The Faraday cage shields the interior from external electromagnetic radiation if the holes in the mesh are significantly smaller than the wave- length of the radiation. Numerous materials for EMP shielding, metal foil, metal mesh, and metal fabrics, are available and can be purchased, but none of these attenuate sound as recommended by the National Cybersecurity and Communications Integration Center, nor do they provide thermal insulation. SUMMARY The present invention overcomes the problems associated with the prior art by providing building materials (e.g., drywall, plaster, etc.) that provide EMP protection as well as sound proofing and thermal insulation. The invention facilitates the production of a low mass, composite EMP-Drywall that eliminates an electromagnetic pulse, acts as a sound barrier, and provides thermal insulation. Alternatively, an EMP-Plaster consisting of layers of plaster-like materials can be applied by trowel or similar method to curved and flat surfaces. The EMP-Plaster eliminates an electromagnetic pulse, acts as a sound barrier, and provides thermal insulation. An example building material can include an electromagnetic pulse-(EMP- )resistant drywall. In an example embodiment, the EMP-resistant drywall is a laminate board consisting of two sheets similar in shape to conventional drywall. The two sheets can include a first sheet that neutralizes electromagnetic radiation (i.e., the EMP-Barrier), and a second sheet that attenuates acoustic energy (i.e., the Acoustic-Barrier). In a particular example embodiment, the second sheet also provides thermal insulation. In a more particular example embodiment, the first sheet consists of sealed and hollow spheres coated with an external electrical conducting layer. For example, the electrical conducting layer can be a metal, metal alloy, or compound. Example coating processes for coating the hollow spheres with the external electrical conducting layer is also disclosed. The coating process can include vapor deposition of metal, metal alloy, or electrical conducting compound. An even more particular example process includes vapor deposition of metal at a temperature low enough to prevent oxidation. Another even more particular example process includes Docket No.: 0206-018P1PCT vapor deposition of metal at a temperature low enough to prevent decomposition of the applied layer. Yet another even more particular example process includes vapor deposition of metal that does not form a nonelectrical conducting (e.g., insulating) compound with the wall of the hollow structure. In another more particular example process, a metal, a metal alloy, or an electrical conducting compound is applied to an exterior surface of a seed prior to transformation. In one more particular example embodiment, the metal, the metal alloy, or the electrical conducting compound fuses and wets the exterior surface of the seed as it is transformed into a hollow sphere. In another more particular example embodiment, the metal, the metal alloy, or the electrical conducting compound does not wet the surface of the seed as it is transformed into a hollow sphere. Instead, the metal, the metal alloy, or the electrical conducting compound forms small spheres on the exterior surface of the seed as it is transformed into a hollow sphere. The small spheres can nearly completely cover the exterior of the hollow sphere and / or the small spheres can provide electrical continuity between the hollow spheres coated with the metal, the metal alloy, or the electrical conducting compound in the EMP-Barrier. In another even more particular example embodiment, the metal, the metal alloy, or the electrical conducting compound can be coated on the hollow spheres at a temperature where the structure of the hollow sphere is stable. In yet an even more particular example embodiment, the metal, the metal alloy, or the electrical conducting compound can react with the exterior surface of the hollow structure forming an intermetallic compound, silicate, and / or oxide that, under reducing conditions at a lower temperature, forms a stable and electrical conducting layer on the exterior of the hollow sphere. The stable layer can nearly completely cover the exterior of the hollow sphere and / or the stable and electrical conducting layer can provide electrical continuity between the coated hollow spheres in the EMP-Barrier. In another particular example embodiment, the metal compound is applied to the exterior surface of the seed and is incorporated, or partially incorporated, into the glass forming the wall of the sphere during the seed’s thermal transformation. In a more particular example embodiment, the compound is partially or totally reduced using a reducing environment to form an electrical conducting phase. In an even more particular example embodiment, the electrical conducting layer nearly completely covers the exterior Docket No.: 0206-018P1PCT of the hollow sphere and / or provides electrical continuity between the coated hollow spheres in the EMP-Barrier. In yet another particular example embodiment, the coating of a seed contains a metallic compound. In a more particular example embodiment, the compound is partially or totally converted to an electrical conducting material using a reducing environment before, during, or after transformation of the seed into a hollow sphere. In an even more particular example embodiment, the electrical conducting layer nearly completely covers the exterior of the hollow sphere and / or the electrical conducting layer provides electrical continuity between the coated hollow spheres in the EMP-Barrier. In another particular example embodiment, the coated hollow spheres are placed in face centered cubic (FCC) packing or hexagonal close packing (HCP). The location of the coated hollow spheres can be fixed by a filler material occupying the interstices between the coated hollow spheres that are in contact with each other. In a more particular example embodiment, the filler material occupies 26 percent of the volume. In another more particular example embodiment, the filler material occupies the holes in the EMP- Barrier. In yet another more particular example embodiment, the diameter of the holes for EMP to penetrate the material are approximately equal to the radius of the coated spheres. The holes are not particularly straight, and the smaller the holes the greater the level of EMP protection. The resulting EMP-Barrier is three-dimensional structure. In another more particular example embodiment, when the octahedral and tetrahedral sites are occupied by coated hollow spheres, the filler material amounts to 19 percent of the volume. In an even more particular example embodiment, occupation of the octahedral and tetrahedral sites with coated spheres further reduces the hole size for EMP penetration. In another particular example embodiment, the internal pressure of the hollow structures and hollow spheres can be reduced by transforming seeds at lower pressures. In a more particular example embodiment, the low pressure reflects sound. The lower the pressure, the more the sound is reflected. The reflection of sound reduces the thickness of the Acoustic-Barrier needed to meet sound attenuation requirements. The low pressure also improves the Acoustic-Barrier’s ability to also serve as thermal insulation. In another particular example embodiment, the Acoustic-Barrier consists of sealed hollow structures with a low internal pressure. In a more particular example embodiment, the low pressure reflects sound. In an even more particular example embodiment, the Docket No.: 0206-018P1PCT lower the pressure the more the sound is reflected. In another even more particular example embodiment, the reflection of sound reduces the thickness of the Acoustic- Barrier to meet sound attenuation requirements. In another more particular example embodiment, the low pressure improves the Acoustic-Barrier’s ability to also serve as thermal insulation. In yet another more particular example embodiment, the sealed hollow structures are formed in layers with each layer consisting of many hollow structures. In still another more particular example embodiment, the hollow structures can be both elongated and their centers offset between layers in a direction 90° with respect to the expected direction of heat flow. In an even more particular example embodiment, the elongation and offset of the hollow structures increases the tortuosity for heat flow through the walls of the hollow structures and raises the R-value of the Acoustic-Board. In another particular example embodiment, the gas filled structures of fixed volume are elongated in a direction oriented 90 degrees with respect to a direction of heat flow. In a more particular example embodiment, the distance between walls is narrowed in a direction oriented 90 degrees with respect to a direction of heat flow. In an even more particular example embodiment, narrowing of the gap between walls and decreasing an internal pressure of the hollow structures shifts the behavior of gas molecules from molecular flow to Knudsen flow. The shift to Knudsen flow reduces the thermal conductivity of gas in the hollow structure. Another example building material includes an EMP-protective plaster. In the example, the plaster is a laminate consisting of two layers that can be applied with a trowel or similar device to curved and flat surfaces. A particular example embodiment includes a first layer that neutralizes electromagnetic radiation (i.e., the EMP-Mud) and a second layer that attenuates acoustic energy (i.e., the Acoustic-Mud). In a more particular example embodiment, the second layer also provides thermal insulation. In another more particular example embodiment the first layer (EMP-Mud) is allowed to cure before applying the second layer (Acoustic-Mud). BRIEF DESCRIPTION OF THE DRAWINGS The present invention is described with reference to the following drawings, wherein like reference numbers denote substantially similar elements: FIG.1 is a front view of a wall including EMP-protective drywall; Docket No.: 0206-018P1PCT FIG.2 is a perspective view of the EMP-protective drywall of FIG.1; FIG.3 is a sectional view of particular layers of the EMP-protective drywall of FIG.1; FIG.4A is a top view of an example configuration of hollow spheres; FIG.4B is a top view of another example configuration of the hollow spheres of FIG.4A including an additional layer; FIG.4C is a top view of yet another example configuration of the hollow spheres of FIG.4A including another additional layer; FIG.4D is a top view of still another example configuration of the hollow spheres of FIG.4A including an alternative to the additional layer of FIG.4C; FIG.5 is a top view of an example configuration of the hollow spheres of FIG.4A including additional smaller hollow spheres; and FIG.6 is a perspective view showing a drywall knife with a portion of EMP- protective mud. DETAILED DESCRIPTION The present invention overcomes the problems associated with the prior art, by providing electromagnetic pulse (EMP) protective building materials. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. Those skilled in the art will recognize, however, that the invention may be practiced apart from these specific details. In other instances, details of well-known construction practices and components have been omitted, so as not to unnecessarily obscure the present invention. Throughout this disclosure, the hollow structures used in the manufacture of the innovative construction materials are referred to as hollow "spheres". However, a person of ordinary skill in the art will understand that the structures need not necessarily be spherical. Rather, the structures can be any shape including, but not limited to spheroidal, ellipsoidal, cylindrical, cuboidal, irregular, and so on. FIG.1 shows a portion of a wall 100 including two panels of EMP-Drywall 102. Wall 100 includes a top plate 104, a bottom plate 106, and a plurality of studs 108. EMP- Drywall 102 is affixed to top plate 104, bottom plate 106, and studs 108 via screws. Two sections of EMP-Drywall 102 are seamed together utilizing EMP-Mud and / or EMP- Docket No.: 0206-018P1PCT Plaster 110. It should be apparent to one of ordinary skill in the art, particularly in view of the present disclosure, that the specific details surrounding wall 100 are non-limiting and merely illustrative in nature. In alternative embodiments, alternate wall structures (e.g., steel beam) and alternate adhesion methods (e.g., contractor’s adhesive, nails, tongue and groove, etc.) can be used. Additionally, while the present disclosure specifically discusses the use and production of EMP drywall, the disclosed EMP protection can be embodied in any other construction materials including, but not limited to, sheathing, subflooring, flooring, underlayment, insulation, roofing, house-wrap, doors, masonry, ceilings, etc., without departing from the scope of the present invention. Panels can be installed in a similar procedure as with conventional drywall. As in the example embodiment, seams between sheets of the EPM-Drywall 102 can be sealed with EMP-Mud 110. As another non-limiting example, the seam between two EMP- Panels can be machined and fitted together with an overlap similar to that associated with shiplap lumber. In yet another example embodiment, the EMP-Drywall 102 can be fit together with a tongue and groove and mudded with EMP-Mud 110 and / or traditional drywall mud. These and other alternatives should be apparent to one of ordinary skill in the art, particularly in view of the present disclosure. The electrically conductive EMP portion of EMP Drywall 102 can be tied to ground either directly or via the electrical system 112 of the structure in which the EMP Drywall 102 is installed. In this example, EMP-Mud 110 provides a grounding contact. FIG.2 shows a perspective view of EMP-Drywall 102. EMP-Drywall 102 is a two-layer laminate board consisting of an EMP-Barrier 202 and an Acoustic-Barrier 204, the latter also acting as thermal insulation. The board is similar to conventional drywall with the exception that its density is less and, therefore, a sheet of EMP-Drywall 102 weighs a fraction of the weight of conventional wallboard of identical surface area and thickness. The difference in weight is primarily dependent on the choice of the electrical conducting material and its thickness used in EMP-Barrier 202. A 0.57-micron layer of copper in EMP-Barrier 202 produces a EMP-Drywall 102 with a 95% weight reduction in comparison to conventional drywall. EMP-Drywall 102 can have a paper face 206 on both exterior surfaces that can be painted and / or finished, as is done with conventional drywall. Docket No.: 0206-018P1PCT EMP-Barrier 202 provides EMP protection via a lattice of hollow spheres, which are coated in a conductive material to form a Faraday cage or a Faraday shield. In various embodiments, the hollow spheres can be glass and / or silica, can have any of a range of internal pressures, can have any of a range of radii, and can have any of a range of wall- thicknesses, depending on a number of production variables. In any particular example EMP-Barrier, the hollow spheres can all have a fixed material, size, shape, internal pressure, wall-thickness, etc. Alternatively, each example EMP-Barrier can include a variety of hollow spheres each having a different set of characteristics. Additionally, example EMP-Barriers can include a filler that fills space between the hollow spheres, gas pockets between the hollow spheres, and / or a sealed vacuum between the hollow spheres. Depending on the choice of filler, the hollow spheres can be fixed with respect to one another or they can be allowed to move with respect to one another. Some example EMP- Barriers having particular traits will be discussed in detail below, however, these particular example EMP-Barriers are presented by way of example and should not be considered limiting. Acoustic-Barrier 204 is similar to EMP-Barrier 202, except the hollow spheres do not include a coating of conductive material. Additionally, acoustic-barrier 204 is intended to prevent the transmission of sound and / or thermal energy across EMP-Drywall 102. Again, particular examples of Acoustic-Barriers having particular traits are discussed in detail below, but these particular example Acoustic-Barriers should not be considered limiting. In the example embodiment, the hollow spheres are generated by heating a seed. An example seed consists of a core surrounded by a coating. Heating the coating forms a glass or fused silica, while a chemical reaction in the core generates a gas that expands the coating to form a hollow sphere. That process is referred to as transformation. The size and shape of the seed affect the size and shape of the hollow sphere, and the relative amounts of core and coating affect the wall thickness and internal pressure of the hollow sphere. Additionally, the temperature of transformation affects the size, wall thickness, and internal pressure of the hollow sphere. Additional information regarding the use of seeds to generate hollow spheres can be found in U.S. Patent Application No.17 / 468,138 entitled “Methods for Producing and Products Including Hollow Silica or Hollow Glass Spheres” and U.S. Patent Application No.15 / 399,592 entitled “Refining Process for Docket No.: 0206-018P1PCT Producing Solar Silicon, Silicon Carbide, High-Purity Graphite, and Hollow Silica Microspheres, which are both filed by the same inventor and incorporated herein by reference in their respective entireties. In example embodiments, there are several types of hollow spheres that can be used in both EMP-Barriers and Acoustic-Barriers. In particular, vacuum spheres (“VacuSpheres”) and insulated spheres (“InsulSpheres”) are utilized for various purposes. A VacuSphere is a hollow sphere with an internal gas pressure below 10-3 atm. VacuSpheres and VacuBoards will typically have a sealed internal pressure of 10-6 to 10-8 atm. The sphere can be formed from glass and / or high-silica glass. Minimum transformation temperature is approximately 1,720°C. An InsulSphere (alse referred to as a HollowSphere) is a hollow sphere with an internal gas pressure at and above 10-3 atm. The sphere can be formed from glass or fused silica. InsulSpheres are formed at temperatures below 1,000°C with glass walls or at temperatures above 2,000°C with fused silica. At the lower temperature carbonate decomposition produces the gas that transforms the seed into a hollow sphere, with the internal pressure of CO2(g) at 0.25 atm or lower at room temperature. In various example embodiments, there are a number of alternative methods for setting the hollow spheres in place with respect to one another in either the EMP-Barrier or the Acoustic-Barrier. Three particular example methods each result in a different type of barrier including boards, panels, and flexible blankets. A board is formed from a plurality of hollow spheres that impinge on one another without a filler material in the spaces between the spheres. Instead, the spaces between spheres are sealed and filled with gases at varying pressures (including vacuum or near- vacuum, for example). In various example embodiments, boards have varying properties based on the type of hollow spheres and the particular distribution of the spheres in the boards. Particular example board types include, but are not limited to, vacuum boards (“VacuBoards”), random vacuum boards (“RandomVacuBoards”), insulated boards (“InsulBoards”), and random insulated boards (“RandomInsulBoards”). An example VacuBoard is made with a Grid Surface Technique (GST). It consists of layers of sealed hollow structures formed with high-silica glass at a temperature of approximately 1,720°C with internal gas pressure below 10-3 atm at room temperature. The internal pressure can be decreased by reducing the pressure during transformation. Docket No.: 0206-018P1PCT The hollow structures can be in any shape and can reflect acoustic energy having a Sound Transmission Class (STC) rating greater than 90. To achieve high R-values, the hollow structures can both be elongated and have their centers offset between layers, in a direction that is 90 degrees with respect to the direction of heat flow, to increase tortuosity. An example VacuBoard is nonporous and can have an R-value as high as 30,000 (it should be noted that all R-values in this disclosure are provided in imperial units). More information regarding the Grid Surface Technique and other methods for forming hollow spheres can be found in U.S. Patent Application No.18 / 234,856 filed by the same inventor and entitled “Methods For Producing Seed And Transformation Of Seeds Into Hollow Structures”, which is incorporated herein by reference in its entirety. An example RandomVacuBoard is formed by placing seeds, which upon transformation can form VacuSpheres, in a confined area so that during transformation the sealed hollow structures impinge on each other, but due to the random distribution of the seeds leave sealed gas pockets. The hollow structures can have an internal pressure below 10-3 atm at room temperature, whereas the sealed pockets can have an internal pressure at or above 10-3 atm at room temperature. The hollow structures can have random shape, and due to their internal pressure (less than 10-3 atm) can reflect acoustic energy having a Sound Transmission Class (STC) estimated rating greater than 80. A RandomVacuBoard is nonporous and can have an R-value as high as 1,600. An example InsulBoard (also referred to as a HollowBoard) is made with the Grid Surface Technique (GST). It consists of layers of sealed hollow structures formed with glass at temperatures below 1000°C or fused silica at temperatures above 2,000°C. The hollow structures have an internal gas pressure at and above 10-3 atm at room temperature. The hollow structures can be in any shape. Their ability to reflect acoustic energy is low but can be improved through transforming the seeds into hollow structures at pressures below 1 atm, thereby decreasing the internal pressure below 0.25 atm at room temperature. To achieve high R-values the hollow structures in a layer are both elongated and their centers offset between layers in a direction 90 degrees with respect to the direction of heat flow to increase tortuosity, and to decrease the spacing between walls in the direction of heat flow, to transition the sealed gas from free molecular flow to Knudsen flow. An InsulBoard is nonporous and can have an R-value as high as 8,000. Additional information regarding the production of VacuBoards and InsulBoards (i.e. HollowBoards) Docket No.: 0206-018P1PCT can be found in U.S. Patent Application No.18 / 234,856 filed by the same inventor and entitled “Methods for Producing Seed and Transformation of Seeds into Hollow Structures”, which is incorporated by reference herein in its entirety. An example RandomInsulBoard is formed by placing seeds, which upon transformation, can form InsulSpheres in a confined area, so that during transformation the sealed and hollow structures impinge on each other, but due to the random distribution of the seeds leave sealed gas pockets. Both the hollow structures and gas pockets can have an internal pressure at or above 10-3 atm at room temperature. The hollow structures and sealed pockets can have a random shape and due to their internal pressure can have a low STC rating. A RandomInsulBoard is nonporous and can have an R-value as high as 260. A panel can be formed from a plurality of hollow spheres with a filler material filling the space between the spheres. The particular choice of filler material depends on a number of options, including, but not limited to, the sound and heat insulating properties of the material, the weight, stiffness, shear strength, tensile strength, etc. of the material, the chemical composition of the material, and / or the reactivity of the material with the hollow spheres, the paper faces, any adhesives or fasteners used in the construction or installation of EMP-Drywall 102, and so on. An example embodiment includes inorganic silicone foam for the filler material. Alternative embodiments can include other polymers, elastomers, and / or copolymers including, but not limited to, styrene-butadiene rubber, polyisoprene, neoprene, nitrile rubber, butyl rubber, chlorosulphonated polyethylene, polybutadiene, organic rubber, polysiloxanes, and so on. Example materials can include additional fillers, such as graphite, or another powdered conductor. The example materials can also be fully or partially cured, uncured, vulcanized or catalyzed, depending on the particular application. Particular example panel types include, but are not limited to, vacuum panels (“VacuPanels”) and insulated panels (“InsulPanels”). An example VacuPanel can be formed from VacuSpheres with a compound (e.g., an inorganic silicone foam) that fills the interstices between the VacuSpheres, fixing the position of the spheres and adding stiffness to the overall structure. A VacuPanel can reflect acoustic energy having a Sound Transmission Class (STC) rating of approximately 76. A VacuPanel can be nonporous or porous depending on the choice of the filler and can have R-values ranging from 230 to 700. Docket No.: 0206-018P1PCT An example InsulPanel can be formed from InsulSpheres with a compound (e.g., an inorganic silicone foam) that fills the interstices between the InsulSpheres, fixing the position of the spheres and adding stiffness to the overall structure. An InsulPanel’s ability to reflect acoustic energy is low, its STC rating being less than 76. An InsulPanel can be nonporous or porous depending on the choice of the filler. The R-value of an InsulPanel is dependent on the choice of filler material and the internal pressure of the InsulSpheres, with a value between 50 to 300 being expected. A flexible blanket (“FlexBlanket”) can be formed from a plurality of hollow spheres with a flexible filler material filling the space between the hollow spheres. A flexible blanket is similar to a panel and can utilize many of the same filler materials. However, a flexible blanket is intended to allow the hollow spheres to move with respect to one another, increasing the flexibility of the panel, whereas a panel is intended to maintain the spatial relationship between the hollow spheres, increasing the stiffness of the panel. Particular example flexible blankets include, but are not limited to, flexible vacuum blankets (“FlexVacuBlankets”) and flexible insulated blankets (“FlexInsulBlanket”). An example FlexVacuBlanket can be flexible and formed from VacuSpheres with silicone rubber that fills the interstices between the spheres allowing the position of the spheres to change as the blanket is flexed. A FlexVacuBlanket can reflect acoustic energy, however its Sound Transmission Class (STC) rating is unknown and is not expected to exceed 70. A FlexVacuBlanket is nonporous and can have R-values ranging from 270 to 440. An example FlexInsulBlanket can be flexible and formed from InsulSpheres with silicone rubber that fills the interstices between the spheres allowing the position of the spheres to change as the blanket is flexed. Both the STC rating and R-value will be low. In the example embodiment, Acoustic-Barrier 204 can be formed from any of the following: a VacuBoard, a RandomVacuBoard, a VacuPanel, or a FlexVacuBlanket. Any of the VacuBoard, RandomVacuBoard, VacuPanel, or FlexVacuBlanket will have high STC ratings due to the low pressures within the hollow structures. Those structures will reflect sound, not having substantial means for absorbing it. Thus, the thickness of the Acoustic-Barrier is not based on sound abatement, but ratheron the desired extent of thermal insulation. With reflected sound, the Acoustic-Barrier can be engineered to provide a desired thermal insulation. Docket No.: 0206-018P1PCT The insulation characteristic of a material is identified by its intrinsic R-value (Rv). The intrinsic R-values for VacuBoards, InsulBoards, RandomVacuBoards, RandomInsulBoards, VacuPanels, InsulPanels FlesVacuBlankets, and FlexInsulBlanket are a function of the size, shape, and wall thickness of the hollow structures, the pressure of gas within the sealed and hollow structures, and the thermal conductivity of filler materials. Selecting an insulating material is based on the material’s extrinsic Rv, which is a function of its intrinsic Rvand its thickness. An example of computing an extrinsic Rvinvolves a popular insulation material sold in packages stating the material is 9 inches thick and “R30.” Although not stated, the “R30” is the intrinsic Rvand is in Imperial Units. The extrinsic Rvfor that insulation is the intrinsic Rvmultiplied by [(thickness in inches / 12)ft / 1ft]. Thus, the extrinsic Rvfor the insulation material is 22.5, not the “R30” reported on the packaging. While an example Acoustic-Barrier, by way of non-limiting example, can advantageously include VacuBoard, RandomVacuBoard, VacuPanel, FlexVacuBlanket, and InsulBoards, alternative Acousti-Barriers are not limited to these options. VacuBoards have superior ability to mute sound, not by absorption but by reflection, as sound cannot pass through a vacuum. Thus, the STC ratings for VacuBoards are high, based on the fractional volume of the void spaces. RandomVacuBoard, VacuPanel, FlexVacuBlanket also benefit from having hollow structures with low internal gas pressure and thus high STC ratings. Since the sound is reflected, the STC rating does not increase with thickness; a thin VacuBoard is as effective at muting sound as a thick Vacuboard. InsulBoards can also be utilized advantageously in an Acoustic-Barrier because of their high Rv. InsulBoards can be produced at low external pressure, thereby producing hollow structures at room temperature below the 0.25 atm reported earlier. Their STC rating, although unknown, increases with a decrease of pressure in the sealed hollow structures. The characteristics of a few example formulations of EMP-Drywall are disclosed herein. The examples are based on an EMP-Drywall having a thickness of 1 inch. The examples include specific materials and respective thicknesses in the EMP-Drywall, but these specific details are not intended to be limiting in any respect. Docket No.: 0206-018P1PCT A first example EMP-Drywall includes a 5 / 8-inch EMP-Barrier and a 3 / 8-inch Acoustic-Barrier. The EMP-Barrier can be an EMP-VacuPanel or an EMP-InsulPanel (LSP 1.5 – 500). It should be noted that “LSP XX – YYY” indicates the wall thickness (XX) in microns and the radius (YYY) of the hollow structure in microns which were used in developing numbers for spheres and non-spherical shapes. With respect to non- spherical shapes the numbers provide information on the mass of material employed and the volume of the non-spherical shapes (XX no longer is the wall thickness as they will be thinner). The Acoustic-Barrier can be a VacuBoard (LSP 1.5 – 400). The VacuBoard can have an STC rating greater than 90, an intrinsic Rvfrom 450 to 11,000, and an extrinsic Rvfrom 14.1 to 344. Another example EMP-Drywall includes a 3 / 8-inch EMP-Barrier and a 5 / 8-inch Acoustic-Barrier. The EMP-Barrier can be an EMP-VacuPanel or EMP-InsulPanel (LSP 1.5 – 500). The Acoustic-Barrier can be a VacuBoard (LSP 1.5 – 400). The VacuBoard can have an STC rating greater than 90, an intrinsic Rvfrom 450 to 11,000, and an extrinsic Rvfrom 23.4 to 573. Yet another example EMP-Drywall includes a 5 / 8-inch EMP-Barrier and a 3 / 8- inch Acoustic-Barrier. The EMP-Barrier can be an EMP-VacuPanel or an EMP- InsulPanel (LSP 1.5 – 500). The Acoustic-Barrier can be a VacuPanel (LSP 3.0 – 600). The VacuPanel can have an STC rating of approximately 76, an intrinsic Rvequal to 455, and an extrinsic Rvequal to 14.2. Yet another example EMP-Drywall includes a 3 / 8-inch EMP-Barrier and a 5 / 8- inch Acoustic-Barrier. The EMP-Barrier can be an EMP-VacuPanel or an EMP- InsulPanel (LSP 1.5 – 500). The Acoustic_Barrier can be a VacuPanel (LSP 3.0 – 600). The VacuPanel can have an STC rating of approximately 76, an intrinsic Rvequal to 455, and an extrinsic Rvequal to 23.7. Yet another example EMP-Drywall includes a 5 / 8-inch EMP-Barrier and a 3 / 8- inch Acoustic-Barrier. The EMP-Barrier can be an EMP-VacuPanel or an EMP- InsulPanel (LSP 1.5 – 500). The Acoustic-Barrier can be an InsulBoard (LSP 3.0 – 600). The InsulBoard can have an STC rating of less than 76, an intrinsic Rvfrom 520 to 6,100, and an extrinsic Rvfrom 16.2 to 191. Yet another example EMP-Drywall includes a 3 / 8-inch EMP-Barrier and a 5 / 8- inch Acoustic-Barrier. The EMP-Barrier can be an EMP-VacuPanel or an EMP- Docket No.: 0206-018P1PCT InsulPanel (LSP 1.5 – 500). The Acoustic-Barrier can be an InsulBoard (LSP 3.0 – 600). The InsulBoard can have an STC Rating less than 76, an intrinsic Rvfrom 520 to 6,100, and an extrinsic Rvfrom 27.1 to 318. Yet another example EMP-Drywall includes a 5 / 8-inch EMP-Barrier and a 3 / 8- inch Acoustic-Barrier. The EMP-Barrier can be an EMP-VacuPanel or an EMP- InsulPanel (LSP 1.5 – 500). The Acoustic Barrier can be an InsulPanel (LSP 3.0 – 600). The InsulPanel can have an STC Rating less than 76, an intrinsic Rvfrom 50 to 300 (estimated), and an extrinsic Rvfrom 1.56 to 9.38. Yet another example EMP-Drywall includes a 3 / 8-inch EMP-Barrier and a 5 / 8- inch Acoustic-Barrier. The EMP-Barrier can be an EMP-VacuPanel or an EMP- InsulPanel (LSP 1.5 – 500). The Acoustic-Barrier can be an InsulPanel (LSP 3.0 – 600). The InsulPanel can have an STC Rating less than 76, an intrinsic Rvfrom 50 to 300 (estimated), and an extrinsic Rvfrom 2.60 to 15.6 Using the extrinsic Rvit is possible to compare the effectiveness of insulation for the above Acoustic-Barriers to that of the popular 9-inch-thick insulation that can be purchased in hardware stores, which has an extrinsic Rvof 22.5. By comparison 5 / 8 inches of the VacuPanel in Example 2b has slightly better insulating ability than 9 inches of the popular material. R-values for Boards and Panels vary with size, shape, and wall thickness of the hollow structures, the pressure of gas within the sealed and hollow structures, as well as the Rvof the filler material. In the above example having a 5 / 8 inch VacuBoard, the extrinsic Rvfor the VacuBoard ranges from 23.4 to 573. The lower number is slightly better than that for the popular insulation, and 5 / 8 inch of VacuBoard insulation is equivalent to the 9 inches of the popular insulation. However, for the larger extrinsic Rv, the insulation of the VacuBoard is equivalent to 230 inches of the popular “R30” insulation on the market today. FIG.3 is a sectioned view of a particular example EMP-Barrier 202. The example EMP-Barrier shown in FIG.3 includes an EMP-VacuPanel 302, which is a VacuPanel formed from metal-coated (as one example) VacuSpheres, the coating being an electrically conducting material. One particular alternative EMP-Barrier can include an EMP- InsulPanel, which is an InsulPanel formed from metal-coated (as one example) InsulSpheres, the coating being an electrical conducting material. Docket No.: 0206-018P1PCT Hollow spheres (these can be VacuSpheres or InsulSpheres) with an exterior coating of an electrical conducting material are used to form an EMP-VacuPanel or an EMP-InsulPanel, both to form a Faraday cage to render harmless an electromagnetic pulse. A Faraday cage shields the interior from external electromagnetic radiation if the holes in the mesh are significantly smaller than the wave-length of the radiation. Wavelengths are presented for different frequencies in Table I. Table I: Characteristics of Electromagnetic Radiation Frequency Wavelength (GHz) 10 2.997 cm 150 2 mm 300 1 mm 600 500 microns 1,000 300 microns 1,200 250 microns 2,400 125 microns 6,000 50 microns 12,000 25 microns 30,000 10 microns In Table I, the maximum frequency identified by the National Cybersecurity and Communications Integration Center’s report is in bold type having a wavelength of 2.997 cm. FIG.3 shows a side view of a portion of a Faraday cage’s wall made with metal coated hollow spheres and filler forming the EMP-Barrier. It is proposed that the Faraday cage can be formed with either an EMP-VacuPanel or an EMP-InsulPanel, but from this point forward in this section, and for simplicity, they are referred to as an EMP-Panel. The EMP-Panel 302 consists of hollow spheres 304 (VacuSpheres in this example, but can be InsulSpheres in alternate embodiments) with an elemental coating 306 of copper on the exterior surface. The electronic conductor can be any of the following Cu, Ni, Fe, Co, Pb, metallic alloys, any of the precious metals, or any other electrical conducting compound. Docket No.: 0206-018P1PCT This list is by way of example and is not to be considered as limiting. The coated spheres are in contact with each other, and a silicone foam 308, or other suitable material, is used to keep the hollow and coated spheres in place and in contact with each other. Additional information regarding the production of metal containing hollow spheres can be found in U.S. Patent Application No.17 / 002,645 filed by the same inventor and entitled “Methods for Producing Hollow Ceramic Spheres”, which is incorporated by reference herein in its entirety. FIG.3 shows multiple sizes of hollow spheres in EMP-Panel 302. In alternative embodiments, a single size of hollow spheres can be used instead. FIGs.4A-4D are overhead views showing several layers of hollow spheres in two possible orientations. FIG.4A shows a plurality of hollow spheres close packed in a first layer 402, where each internal sphere is in contact with six adjacent spheres. FIG.4B shows a second layer 404 placed directly over first layer 402. FIG.4C shows a third layer 406 placed over second layer 404 in a hexagonal close-packed (HCP) formation. FIG.4D shows a fourth layer 408 placed over second layer 404 (with third layer 406 omitted) in a face-centered cubic (FCC) formation. FCC & HCP packing occurs naturally with slight vibrations during the positioning of the hollow spheres or the seeds that produce the hollow spheres. If a single size of metal-coated sphere is used in the FCC formation or the HCP formation, then the openings, or holes, will have a diameter approximately equal to the radius of the hollow spheres used to form EMP-Panel 302. The hole size is a function of the size of the coated hollow spheres, getting smaller with smaller spheres. That hole will not have a straight path through the panel but will crisscross. Hereinafter, the term “close packing” is used to represent both FCC and HCP. The hole can be blocked by using additional smaller size metal-coated hollow spheres as presented in FIG.3. Hollow spheres of identical size in close packing occupy 74% of the volume, leaving 26% occupied by filler that acts as holes for EMP migration. With close packing there are eight tetrahedral sites and four octahedral sites per 4 hollow spheres in both the FCC and HCP configurations (FCC has 4 octahedral and 8 tetrahedral sites per 4-spheres per unit cell, whereas HCP has 6 octahedral and 12 tetrahedral sites per 6-spheres per unit cell.). FIG.5 shows an overhead view of a layer 502 of multi-sized spheres in a close- packed configuration, illustrating the reduction in the hole size of the Faraday cage. When Docket No.: 0206-018P1PCT the tetrahedral and octahedral sites are occupied, the FCC holes in the drywall are reduced from 26 volume percent to 19%. The filling of these additional sites further decreases the size of the holes for electromigration. The filling of the tetrahedral and octahedral sites reduces the hole size by an additional 50%. The result for the HCP structure is similar. The choice of metal or metal alloy to form the Faraday cage of EMP-Panel 302 depends on how the VacuSpheres or InsulSpheres (i.e., hollow spheres) are to be coated. If a chemical vapor deposition process is used to coat hollow spheres at a temperature low enough that the metal, metal alloy, and / or electrical conducting compound does not become oxidized, decompose, or form a nonelectrical conducting compound with the wall of the hollow sphere, and the vapor deposited material completely covers the exterior of the hollow sphere, then there is no limit on the choice of metal or alloy. If the metal, metal alloy, and / or metal containing compound is applied to the exterior surface of a seed, and thus is exposed to the thermal conditions associated with transforming the seed into a hollow sphere, there can be physico-chemical limitations. These limitations can include: 1. If a metal, metal alloy, and / or metal containing compound is applied to the exterior surface of a seed, it can fuse during the thermal transformation of the seed. The metal, metal alloy, and / or metal containing compound can wet the exterior surface of the seed as it is transformed into a hollow sphere. 2. If a molten metal, metal alloy, and / or metal containing compound does not wet the exterior surface of hollow spheres or a seed as it is transformed into a hollow sphere, but forms small spheres of metal, metal alloy, and / or metal containing compound on the exterior surface of the wall of the hollow sphere that metal or metal alloy coverage is acceptable, provided: a. the coverage of the glass wall of the hollow spheres by the small metal, metal alloy, or metal containing compound spheres is nearly complete, and / or Docket No.: 0206-018P1PCT b. the small metal, metal alloy, or metal containing compound spheres have electrical continuity between the hollow spheres in the EMP-Barrier. 3. Hollow spheres coated with a metal, metal alloy, and / or metal containing compound at a temperature that allows the hollow spheres to retain their shape due to adequate viscosity of its walls, but the metal, metal alloy, and / or metal containing compound undergo chemical reaction with the walls of the hollow spheres forming intermetallic compounds, silicates, and / or oxides that under reducing conditions at a lower temperature produce an electrically conducting stable layer on the exterior of the hollow spheres is acceptable, provided: a. the coverage of the glass wall of the hollow spheres by the electrical conducting layer is nearly complete, and / or b. the electrical conducting layer provides electrical continuity between the hollow spheres in the EMP-Barrier. Other processes include addition, or total inclusion, of compounds in the seed's coating. Some non-limiting examples include: 4. A metal compound, e.g. an oxide, can be applied to the exterior surface of the seed, and can be incorporated, or partially incorporated, into the glass forming the wall of the sphere during the seed’s thermal transformation. Reducing some or all of the oxide to its solid metallic state, through use of a reducing environment such as H2(g) or CO(g), forms a metallic layer covering all or a significant portion of the exterior surface of the hollow sphere. The metal can be produced at a temperature low enough to minimize surface migration of the metallic atoms, and the metal provides metal to metal contact between the coated spheres in the EMP-Barrier. 5. The coating of a seed can contain a metallic compound that before, during, or after transformation, when exposed to a reducing environment, can produce an electrical conducting Docket No.: 0206-018P1PCT layer covering all or nearly all the exterior surface of the hollow sphere, and can provide electrical continuity between the hollow spheres in the EMP-Barrier. The electrical conductor-coated VacuSpheres and / or InsulSpheres in close packing are infused with a filler, one such filler being a silicone foam to lock the spheres in place and, in the process, forming a board with electrical continuity. The number of layers of close packed hollow spheres forming the wall of the Faraday cage will depend on the diameter of the metal-coated spheres and the thickness of the EMP-Barrier. A 5 / 8-inch thick EMP-Barrier formed with 1mm diameter metal coated spheres can include approximately 16 layers, whereas 0.1mm diameter spheres can include approximately 160 layers. Each layer can be offset from the previous layer eliminating any direct path a hole has through the board. The Faraday cage, instead of being 2-dimensional as with wire mesh, becomes 3-dimensional. The wavelength of electromagnetic radiation at 10GHz is 2.997 cm, which is a minimum wavelength according to the Executive Summary of the National Cybersecurity and Communications Integration Center’s report. The 10GHZ is a maximum limiting frequency identified in the NCCIC’s report. The 2.997cm wavelength is significantly larger than the holes in an EMP-Barrier made with close packed spheres. The ratios of the hole diameters made with those spheres to the 2.997 cm wavelength are 0.017 and 0.0017 for 1mm and 0.1mm diameter spheres, respectively. An example EMP-Barrier made with those spheres meets the requirement for a Faraday cage, namely that the holes must be significantly smaller than the wavelength. FIG.6 is a side view of a drywall knife 600 including a glob of EMP-Mud 602. EMP-Plaster is a two-layer laminate consisting of EMP-Mud and an Acoustic-Mud, the latter also acting as thermal insulation. The plaster is similar to conventional plaster with the exception that it is less dense. Each layer, EMP-Mud and Acoustic-Mud, can be applied with drywall knife 600 or a similar device (e.g., a trowel) to both curved and flat surfaces to the desired thickness. EMP-Mud 602 is a plaster-like material consisting of metal (as an example) coated VacuSpheres (or InsulSpheres), the coating being an electrical conducting material, combined with a low-viscosity mud-like material that, when mixed with the coated spheres, can be applied with a trowel to both curved and flat surfaces. The viscosity of the Docket No.: 0206-018P1PCT EMP-Mud is high enough to keep the mud in place after being applied with the drywall knife, and the mud-like material hardens as it cures. The mud-like material can contain electrical conducting particulate that, when mixed with the coated spheres, improve electrical conductivity between the spheres as well as for the EMP-Mud. The EMP-Mud can also serve to electrically connect the "Faraday cages" of adjacent EMP wallboard panels 102 and / or to connect panels 102 to ground 112. Acoustic-Mud (not shown, but visually similar to EMP-Mud 602) is a plaster-like material consisting of VacuSpheres (or InsulSpheres) combined with a low viscosity mud- like material that, when mixed with the coated spheres, can be applied with a trowel to both curved and flat surfaces. The viscosity of the Acoustic-Mud is high enough to keep the mud in place after being applied with the trowel, and the mud-like material hardens as it cures. In the EMP-Mud and the Acoustic-Mud, close packing of the spheres occurs naturally. The hole size for electromagnetic penetration in EMP-Mud will be similar to that of the EMP-Barrier, and, thus, EMP-Mud will provide similar protection for an electromagnetic pulse as that provided by the EMP-Barrier. Similarly, close packing of the VacuSpheres in Acoustic-Mud will occur naturally and thus its STC rating and R- value will be similar to that for the Acoustic-Barrier formed with VacuSpheres. The description of particular embodiments of the present invention is now complete. Many of the described features may be substituted, altered or omitted without departing from the scope of the invention. For example, alternate drywall structures (e.g., additional layers, thicker layers, thinner layers, etc.), may be substituted for the example drywall structure shown in FIG.2. As another example, alternate filler materials can be utilized in the EMP- and Acoustic-Barriers in place of the silicone foam and silicone rubber that is disclosed, by way of example, herein. These and other deviations from the particular embodiments shown will be apparent to those skilled in the art, particularly in view of the foregoing disclosure.

Claims

Docket No.: 0206-018P1PCT We claim:

1. A barrier for preventing electromagnetic pulse (EMP) damage within a structure, comprising: a first layer configured to attenuate an electro-magnetic pulse (EMP), said first layer having a front surface and a rear surface, said front surface and said rear surface defining a first space therebetween; and a first plurality of hollow structures disposed within said first space, said hollow structures having an electrically conductive material on their outer surfaces and being in contact with one another.

2. The barrier of Claim 1, further comprising: a second layer configured to attenuate acoustic energy, said second layer having a front surface and a rear surface, said front surface of said second layer and said rear surface of said second layer defining a second space therebetween; and a second plurality of hollow structures disposed within said second space, said hollow structures of said first plurality of hollow structures having a composition different than a composition of said hollow structures of said second plurality of said hollow structures.

3. The barrier of Claim 2, wherein said first layer and said second layer are layers of a flexible blanket.

4. The barrier of Claim 3, further comprising silicone rubber disposed in said second space in interstices between said hollow structures of said second plurality of hollow structures.

5. The barrier of Claim 2, wherein said first layer and said second layer are layers of a wallboard.

6. The barrier of Claim 5, wherein said first layer is thicker than said second layer.Docket No.: 0206-018P1PCT 7. The barrier of Claim 5, wherein said second layer is thicker than said first layer.

8. The barrier of Claim 5, wherein said hollow structures of said first plurality of hollow structures have an internal pressure that is less than 10-3 atm.

9. The barrier of Claim 5, wherein said hollow structures of said first plurality of hollow structures have an internal pressure that is greater than or equal to 10-3 atm.

10. The barrier of Claim 5, further comprising a filler disposed in said first space, said filler fixing said hollow structures of said first plurality of hollow structures in place with respect to one another.

11. The barrier of Claim 10, wherein said filler is silicone foam.

12. The barrier of Claim 5, wherein said hollow structures have walls of glass.

13. The barrier of Claim 5, wherein said hollow structures have walls of fused silica.

14. The barrier of Claim 5, wherein: said front surface of said first layer lies substantially in a plane; said hollow structures of said first plurality of hollow structures are arranged in close-packed layers; and centers of said hollow structures of a first one of said close-packed layers are offset with respect to centers of said hollow structures of an adjacent close- packed layer in a direction parallel to said plane.

15. The barrier of Claim 14, wherein said close-packed layers are arranged in a face centered cubic lattice structure.

16. The barrier of Claim 14, wherein said close-packed layers are arranged in a hexagonal lattice structure.Docket No.: 0206-018P1PCT 17. The barrier of Claim 1, further comprising an electrical contact coupled to said first plurality of hollow structures and disposed to facilitate the electrical connection of said first plurality of hollow structures to ground.

18. The barrier of Claim 5, further comprising a second wallboard, said second wallboard including: a first layer configured to attenuate an electro-magnetic pulse (EMP), said first layer having a front surface and a rear surface, said front surface and said rear surface defining a first space therebetween; and a first plurality of hollow structures disposed within said first space, said hollow structures having an electrically conductive material on their outer surfaces and being in contact with one another.

19. The barrier of Claim 18, further comprising an EMP compound, and wherein: said EMP compound includes a plurality of hollow structures having an electrically conductive material disposed on their outer surfaces; said first wallboard is disposed adjacent said second wallboard; said EMP compound is disposed between said first wallboard and said second wallboard; and said hollow structures of said EMP compound electrically couple said hollow structures of said first layer of said first wallboard with said hollow structures of said first layer of said second wallboard.

20. The barrier of Claim 19, wherein said EMP compound provides an electrical contact for electrically coupling said hollow structures of said first layer of said first wallboard and said hollow structures of said first layer of said second wallboard to ground.

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