Abstract:
A method and system of using a common set of coils to provide at least two of magnetic flux, heat and degaussing in a mobile platform are provided. In accordance with one embodiment, the method involves oscillation of current in the coils at a frequency higher than a defined pointing requirement to provide heat. In accordance with another aspect, the coil functions as a degausser by energizing the coil with an oscillating current that decreases in amplitude over time.

Description:
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     This invention was made with Government support under NRO000-10-C-173 awarded by the Department of Defense. The Government has certain rights in this invention. 
    
    
     FIELD 
     This application relates to a multipurpose electrical coil as a magnetic flux generator, heater or degaussing coil and, more particularly, to a method of using a common set of coils to provide magnetic flux, heat and/or degaussing in a mobile platform. 
     BACKGROUND 
     In the operation of a stabilized orbiting satellite there is always a need to control or limit uncontrolled tumbling of the spacecraft. Such uncontrolled motion of a satellite, intended to be stabilized in orbit, renders the satellite effectively useless for its planned operation. Furthermore, prolonged tumbling at excessive angular momentum may jeopardize the structural integrity of the spacecraft as well as the spacecraft&#39;s thermal and power balance. Therefore, it is desirable that recovery of the satellite occur within a short period of time after tumbling begins. 
     Control of tumbling can be accomplished by mass expulsion devices such as, rocket thrusters or jets. The use of such devices to control or limit spacecraft tumbling often requires excessive propellant usage. In the situation where no propellant is available, such means cannot be used to stabilize the spacecraft. Where electrical power in the satellite is available, it is more desirable to control tumbling by changing the spacecraft&#39;s spin rate by an autonomous control system. 
     Magnetic torquing of stabilized satellites, in particular for changing the attitude of a spacecraft that has deviated from its desired orientation relative to its orbit, is known. Such magnetic torquing systems use a magnetic field from torquers such as coils or electromagnets to interact with the magnetic field of the earth to develop a reaction torque. This reaction torque causes the reference axis of the satellite to be reoriented an amount proportional to the torquing time and flux magnitude. Magnetic torquing can also be used to develop a reaction torque to control the spin rate and the angular momentum of a spacecraft. These known magnetic torquing systems may be implemented in a satellite or spacecraft with an automatic (e.g., closed-loop) control system or an open-loop control system requiring command signals from a ground-situated station. 
     Most electronic devices experience changes in operating characteristics based on their operating temperature. For most applications, these variations are slight and can either be ignored or compensated for through calibration. However, there are instances in which environmental temperature regulation is required to ensure proper operation of an electronic device. For example, in many space applications where unregulated temperatures would be extremely cold, environmental temperature regulation is required. At these extreme temperatures, electronic components may have operating characteristics that are quite different from their operating characteristics at room temperature causing them to malfunction or provide erroneous readings. Further, temperature regulation is also typically required for components of any sort that are particularly sensitive to variations in temperature. 
     In many applications, strip heaters are used in temperature control systems for providing heat to electronic devices. Strip heaters include a resistive element that generates heat when a current is applied thereto. The heating element is typically either an elongated wire or trace of resistive material deposited on a substrate. The heating element is typically arranged in a pattern over a defined area to provide uniform heat over the defined area. When current is applied to the heating element, heat is emitted from the strip heater. 
     While strip heaters are considered an inexpensive and efficient means of providing heat to electronic devices for environmental temperature control, there are some drawbacks to these devices. Specifically, in spacecraft applications strip heaters add mass to the overall system. Minimizing the mass of a spacecraft is key to controlling the high launch expense. 
     In addition to heaters, satellites and other mobile platforms typically include separate degaussing coils for minimizing residual magnetism in equipment on the device. Having separate devices for magnetic flux generation, heating and degaussing adds complexity and mass to the mobile platform. 
     Therefore, it would be desirable to have a method and device that provides for magnetic flux generation, heating and degaussing that is less complex and requires less mass than those systems utilizing separate devices for some or all of these three functions. 
     SUMMARY 
     In one aspect, a method of using a common set of coils to provide at least two of magnetic flux, heating and degaussing in a mobile platform is provided. In accordance with one embodiment, the method involves oscillation of current in the coils at a frequency higher than a defined pointing stability requirement to provide heat. In accordance with another aspect, the coil is energized with an oscillating current that decreases in amplitude over time that enables the coil to serve as a degausser. 
     In another aspect, a system comprising a coil in a mobile platform is provided. The system includes a coil, a power supply for the coil, and a control circuit wherein the control circuit is programmed to operate the coil as a magnetic flux generator, a heater and/or a degausser. In accordance with particular aspects, the coil contains conductive traces. 
     In another aspect, the coil comprises conductive traces on a printed circuit board. The traces may be present on a single layer or on multiple layers. 
     The features, functions, and advantages that have been discussed can be achieved independently in various embodiments of the present invention or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating one aspect of the disclosed system for utilizing a single set of coils as a magnetic flux generator, heater and degausser in accordance with one embodiment of the present disclosure; 
         FIG. 2  is a diagram illustrating the single set of coils of  FIG. 1  as an electrical coil disposed on multi-layers of a printed circuit board; 
         FIG. 3  is a diagram illustrating a side-by-side layer display of the electrical coil disposed on multi-layers of a printed circuit board of  FIG. 2 ; 
         FIG. 4  is a flow chart illustrating a decision matrix for driving a set of coils in accordance with an embodiment of the present disclosure; 
         FIG. 5  is a diagram illustrating display of the system illustrated in  FIGS. 1-3  on a mobile platform in orbit with PCB&#39;s  130  de-attached from the mobile platform to highlight structure aspects; 
         FIG. 6  is a method of  FIGS. 1-5  for driving a set of coils in accordance with an embodiment of the present disclosure; and 
         FIG. 7  is a schematic illustration of an exemplary computing device  400  that may be used with methods and systems shown in  FIGS. 1-6 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , one aspect of the disclosed system  10  includes a power supply  12  that provides inputs (e.g., current, voltage, power) to a controller  14 . In one example, the controller  14  may be an active or passive voltage or current or power output source that adjusts a voltage, current, and/or power level from its input to its output in accordance with control inputs (e.g., sensor data acquired from a mobile platform (e.g., car, boat, plane, spacecraft, or the like)). In one embodiment, the controller  14  energizes the electrical coil  16  (coil  16 ) to provide the desired functionality on the mobile platform (e.g., satellite  190  illustrated in  FIG. 5 ). 
     In one embodiment, the electrical coil  16  (e.g., coil  160 ) includes a multi-layer printed circuit board  140  as illustrated in  FIGS. 2 and 3  to provide multi-function capability on a mobile platform (e.g., satellite  190 ). For instance, the controller  14  applies a level of direct current (DC) to the coil  16  (e.g., coil on multi-layer printed circuit board  140  of  FIGS. 2 and 3 ) to generate a pre-determined level of magnetic flux and become a flux generator  18  (e.g. magnetic flux generator). In one embodiment, in accordance with spacing and length of traces of the coil  160 , the coil  160  may produce magnetic flux such that its magnetic dipole moment is in a range of about 0.1 to 10 ampere-meters 2  that flux varies in accordance with, for instance, a distance from the coil  160  (e.g., of multi-layer board  140 ). As such, the coil  160  operates as a typical electromagnet that provides magnetic flux on the mobile platform (e.g., satellite  190 ). 
     In one embodiment, the controller  14  applies alternating current (AC) to the coil  16  to generate heat (e.g., becomes a heater  20 ) for components (e.g., electronic boards) on the mobile platform. For instance, in one embodiment, the controller  14  supplies alternating current (AC) at a frequency sufficiently high that the average magnetic flux generated is negligible (e.g., the average magnetic field based on switching of magnetic fields for a period of time is negligible). 
     When the coil  16  is operated as a typical electromagnet, it may be used to produce torque in a mobile platform such as a satellite  190 . Current passing through the coil generates a magnetic field to reposition a satellite into a particular orientation. As such, the coil  16  may be used to provide magnetic torquing in conjunction with satellites. Examples of such methods and systems are described in U.S. Pat. No. 4,114,841 to Muhlfelder et al., the contents of which are hereby incorporated by reference. 
     In the heating function of the coil  16 , a high frequency alternating current is supplied to the coil to generate heat while avoiding magnetization of the satellite. The frequency required to generate sufficient heat with negligible average magnetic flux would be dependent upon the mass and responsiveness of the satellite. Typically, the frequency may range from about 1 mHz to 1 KHz, with frequencies near 1 Hz being particularly useful. Typically, the heater will be operated at a few watts depending on the rate at which the satellite radiates heat away into space. Advantageously, as compared to many conventional spacecraft strip heaters having thin copper traces laminated with foil and taped to the substrate that may exhibit trace “lift-off” due to thermal expansion and contraction during heater operation, in this disclosure, the coil  16  may be fabricated using photolithographic processes within the printed circuit board (PCB) to prevent trace separation from the PCB. 
     In yet another embodiment, the controller  14  provides an alternating current (AC) of decreasing amplitude to the coil over time in which case the coil  16  provides a degaussing function (e.g., becomes a degausser  22 ) to minimize residual magnetism in nearby equipment. In this example, the amplitude of the current approaches zero over a “period of time” as the current oscillates back and forth, for example, typically in the range of about 10 Hz-1 kHz. Advantageously, this embodiment prevents stray magnetic flux emissions, even at substantially lower levels, from interfering, for instance, with performance of electronics and, in yet other applications, for example, fiber optics communications and link. Thus, this embodiment may prevent stray magnetic flux introducing output changes, drift, or noise into electronic components, which can corrupt data signals in an electronic device. Furthermore, the degaussing function may reduce or eliminate magnetic disturbances in devices to magnetic fields. Specific examples of devices sensitive (e.g., sensitive equipment) to magnetic disturbances include spectrometers, magnetometers, and the like. 
     Referring to  FIGS. 2 and 3 , the diagram illustrates a magnetic printed circuit board (PCB) having loops of conductive material that form a conductive coil (e.g., electrical coil  160  that is an example of electrical coil  16  of  FIG. 1 ) in accordance with an embodiment of the present application. In this embodiment, the printed circuit board  130  (PCB  130 ) comprises a multi-layer printed circuit board  140  formed of layers  142 ,  144 ,  146 , and  148 . In the illustrated embodiment, the multi-layer printed circuit board  140  comprises four layers; however, it should be understood that the quantity of layers may be otherwise increased or decreased to accommodate various coil formation quantities, properties, and magnetic field generation applications. Additionally, it should be understood that multi-layer printed circuit board  140  may be replaced by one or more discrete single-layer printed circuit boards, where each of these boards has one or more coil formations disposed thereon for generating the magnetic field. 
     In the illustrated embodiment, the conductive traces  132 ,  134 ,  136 , and  138  are formed on one or more layers of the multi-layer printed circuit board  140  to form electrical coils. As used herein, a “conductive trace” may include either a trace formed on a single layer of the multi-layer printed circuit board  140  or a continuous conductive path extending to a plurality of layers of the multi-layer printed circuit board  140  or sides of a single layer of the multi-layer printed circuit board  140 . For example, the conductive traces  132 ,  134 ,  136 , and  138  may extend about each side of a single layer of the multi-layer printed circuit board  140  or may extend to a plurality of layers of the multi-layer printed circuit board  140  to form a coil (e.g., coil  16  in  FIG. 1 ). In the illustrated embodiment, the multi-layer printed circuit board  140  comprises relatively continuous traces  132 ,  134 ,  136 , and  138  extending spirally in layers  142 ,  144 ,  146 , and  148  along the multi-layer printed circuit board  140 . As illustrated in the  FIG. 3  example, the current travels counterclockwise (indicated by direction of arrows) to produce a magnetic field “out” of the printed circuit board  130 . In another variant of  FIG. 3 , the current may travel clockwise (in opposite direction of arrows in  FIG. 3 ) to produce a magnetic field “into” the printed circuit board  130 . 
     However, it should be understood that the electrical coil  160  may be formed using a plurality of discrete conductive traces  132 ,  134 ,  136 , and  138  extending along the multi-layer printed circuit board  140  about either a single layer or multiple layers of the multi-layer printed circuit board  140 . For example, a plurality of discrete conductive traces  132  may be formed spaced apart from each other on the multi-layer printed circuit board  140 . Each of the traces  132 ,  134 ,  136 ,  138  in the above-described example may extend about a single layer or multiple layers of the multi-layer printed circuit board  140  to form a plurality of discrete “coil segments” such that each “coil segment” comprises a conductive path forming an almost complete flattened spiral path within the layer or layers. Thus, together, the plurality of discrete conductive traces  132 ,  134 ,  136 , and  138  form conductive coils extending along the multi-layer printed circuit board  140 . Furthermore, advantageous, the layout of heating coil “traces” may be disposed or laid out in single or multiple layers of one or more circuit boards (e.g., PCBs). 
     In one application of the present disclosure, multiple “heating circuits” may be disposed side-by-side on a same PCB board (e.g., same circuit card) to provide redundant set(s) of heating circuits. Advantageously, this redundancy would prevent loss of heating capability upon failure of one or more sets of heating circuits. In this example, both primary (main) and redundant circuits may be controlled by a single temperature sensor (e.g., sensor  188   a - f ); however, for effective application, electrical current or power to the main and redundant circuit may be driven by independent or separate power sources so as to provide this a fail safe and failure operability capability. In yet another embodiment, referring to most notably to  FIG. 5 , one or more of the faces (faces  1 - 6 ) may be designated a primary (main) or redundant circuit (e.g., circuitry such as coil  160  on multi-layer circuit board  140 ) and if one face fails (e.g., main or redundant), a failing face of PCB  130  may be deactivated (powered-down) and non-failing face inputs received from its designated sensor (e.g., one or more sensors  188   a - f ) may be used to compensate for outputs (e.g., magnetic flux generation, heating, and/or degaussing) of one or more failing face(s) (faces  1 - 6 )). 
     As best illustrated in  FIGS. 2 and 3 , a coil  160  is formed extending across multiple layers  142 ,  144 ,  146 , and  148  of a substrate material (e.g., phenolic, silicon, duroid, alumina) by deposition of the conductive traces  132 ,  134 ,  136  and  138  (e.g., copper metal traces). In this example, the conductive traces  132 ,  134 ,  136 , and  138  extend along layers  142 ,  144 ,  146 , and  148 , respectively and extending between layers  142 ,  144 ,  146 , and  148  through connecting vias  152 ,  154 ,  156 , and  158 , with coil  160  beginning at pad  162  and terminating at pad  164  connected to controller  14  to receive inputs from sensor  188  (e.g., sensors  188   a - f ). 
     It should be understood that the routing of the conductive traces  132 ,  134 ,  136  and  138  connecting vias  152 ,  154 ,  156 , and  158  between the various layers of the multi-layer printed circuit board  140  is exemplary only and may be otherwise modified. Additional layers may be used to form additional conductive traces or may be used to provide multi-layer printed circuit board  140  symmetry. Other layers without conductive electrical coil traces may also be present in multi-layer printed circuit board  140 . The layers  142 ,  144 ,  146 , and  148  may also provide a location for additional signal circuitry and electronic component attachment to the multi-layer printed circuit board  140 . 
     In operation, the controller  14  couples to the coils (e.g., the coil  160 ) of the printed circuit board  130 . The controller  14  selectively energizes and de-energizes each of the coil(s) of the printed circuit board  130  to function as a flux generator  18 , heater  20  and/or degausser  22 . The controller  14  may also control an amplitude and direction of the current generated in each of the coils to provide for the desired function. For example, passing a current through the coil  160  generates a magnetic field that interacts with the earth&#39;s magnetic field resulting in forces and torques acting on a satellite. Referring to  FIG. 5 , the satellite  190  is equipped with the printed circuit board  130  described herein. In this variant, the satellite  190  includes at least one PCB for each face (e.g. 6 faces) of the satellite  190 . 
     Referring to flowchart of  FIG. 4 , a flowchart  200  illustrates principles of the present application, for instance, a method for operating the coil  16 ,  160  illustrated in  FIGS. 1-3  and  5 . 
     In one or more embodiments, “a period of time” depends on the satellite&#39;s control needs, which are, for instance, evaluated at regularly set or one or more control intervals. In one example, the control interval may be no faster than any half-cycle of alternating-direction current in a coil; however, it may be slower. For the heating use, the current direction must alternate fast enough (typically from about a tenth of a Hz up to a few kilohertz) so that any resultant wobble it produces in the mobile platform (e.g., satellite&#39;s orientation) due to, for instance, interaction with the earth&#39;s magnetic field is reduced or diminished. 
     In one exemplary degaussing instance, a similar “negligible wobble” constraint applies and in addition, the frequency and the decreasing of an amplitude of the applied current covers a sufficient range to provide a magnetic field strong enough to degauss or at least reduce magnetization in many sensitive parts or sensitive equipment on the satellite that are of concern. Other details for operation, such as the amplitude and frequency, depend greatly on the proximity of the sensitive component(s) or sensitive equipment to the coil, the configuration of the coil such as number of coils and dimensions of each coil, and the like. For instance, typical maximum currents might be a few hundred milli-amperes to a few amperes, alternating at a few tens of Hertz to a kilo Hertz, and decreasing from maximum amplitude to zero over a few tenths of a second to a few seconds. 
     Referring to  FIG. 4 , following step  202  (start), in step  204 , determine if the satellite  190  is tumbling. If answer is yes for step  204 , then go to step  206  to run DC current to magnetize the coil  16  in the appropriate direction for “a period of time” and go back to start (step  218 ). If answer is no to step  204 , then go to step  208  and determine whether there is a need to use the coil  16  to de-magnetize satellite parts (e.g., spectrometers, magnetometers, and the like). In one variant, the coil  16  provides a reduction of or diminished interactions, for example, for these components, within a mobile platform (e.g., satellite  190 ) due to the earth&#39;s magnetic field to a fraction of a degree or less, which reduction may depend, for instance, on the pointing accuracy required for the mobile platform intended usage. If the answer is yes for step  208 , then go to step  210  to run decreasing amplitude alternating current though the coil  16  for “a period of time” and go back to start (step  218 ). 
     If the answer is no for step  208 , then go to step  212  to determine if there is a need to warm satellite parts. If the answer is yes for step  212 , then go to step  214  to run alternating current through the coil  16  for “a period of time” and go back to start step  218 . For example, the amplitude of the current may be set to produce the desired heating power (typically a few watts) to warm the satellite parts. For instance, the heating power may be based on the square of the RMS (root mean squared) current through the coil  16 , which equals the heating power divided by the coil&#39;s resistance. If the answer is no for step  212 , then turn off the coil  16  for “a period of time” and go back to start (step  218 ). 
     Referring to  FIG. 6 , an exemplary method is disclosed illustrating the apparatus and system disclosed in  FIGS. 1-5 . In step  302 , a mobile platform (e.g., satellite  190  having communication antenna  192 ) exhibits magnetic torquing. In step  304 , a sensor  188  ( 188   a - f ) (e.g., balancing sensor, temperature sensor, momentum sensor, or the like) on the mobile platform measures data, for instance, information on a reference axis of the mobile platform and how the mobile platform is being reoriented, for instance, at an angular momentum rate and communicates the information to system bus A (e.g., communication interface). In step  306 , based on data measurement by the sensor  188  ( 188   a - f ) from system bus A (e.g., communication interface), a controller  14  generates a control signal (e.g., power, current, voltage) that is communicated, for instance, through system bus B, to power one or more coils  160  (e.g., one or more multi-layer printed circuit board(s)  140  disposed on PCB(s)  130 ) situated about one or more locations (e.g., faces  1 - 6 ) of the mobile platform to adjust one or more environmental conditions on the mobile platform (e.g., magnetic flux, heating of components, and/or degaussing). In the exemplary embodiment illustrated in  FIG. 5 , each of the faces is de-attached from the mobile platform so as to illustrate block functionality. In particular, face  1  is a top side of the mobile platform, face  2  is right side of the mobile platform, face  3  is the bottom side of the mobile platform, face  4  is the left side of the mobile platform, face  5  is the front side front side of the mobile platform, and face  6  is the back side of the mobile platform. In step  308 , a desired environmental condition is achieved (e.g., magnetic flux level, heating, and/or degaussing) to improve environmental conditions on the mobile platform. 
       FIG. 7  is a schematic illustration of an exemplary computing device  400  that may be used with systems and methods shown in  FIGS. 1-6 . In the exemplary embodiment, computing device  400  includes a memory device  410  and a processor  420  coupled to memory device  410  for use in executing instructions. More specifically, in the exemplary embodiment, computing device  400  is configurable to perform one or more operations described herein by programming memory device  410  and/or processor  420 . For example, processor  420  may be programmed by encoding an operation as one or more executable instructions and by providing the executable instructions in memory device  410 . 
     Processor  420  may include one or more processing units (e.g., in a multi-core configuration). As used herein, the term “processor” is not limited to integrated circuits referred to in the art as a computer, but rather broadly refers to a controller, a microcontroller, a microcomputer, a programmable logic controller (PLC), an application specific integrated circuit and/or other programmable circuits. 
     In the exemplary embodiment, memory device  410  includes one or more devices (not shown) that enable information such as executable instructions and/or other data to be selectively stored and retrieved. In the exemplary embodiment, such data may include, but is not limited to, signal levels, pulse frequencies, pulse durations, pulse sequences, operational data and/or control algorithms. Memory device  410  may also include one or more computer readable media, such as, without limitation, dynamic random access memory (DRAM), static random access memory (SRAM), a solid state disk and/or a hard disk. 
     In the exemplary embodiment, computing device  400  includes a presentation interface  430  that is coupled to processor  420  for use in presenting information to a user. For example, presentation interface  430  may include a display adapter (not shown) that may couple to a display device (not shown), such as, without limitation, a cathode ray tube (CRT), a liquid crystal display (LCD), a light-emitting diode (LED) display, an organic LED (OLED) display, an “electronic ink” display and/or a printer. In some embodiments, presentation interface  430  includes one or more display devices. 
     Computing device  400 , in the exemplary embodiment, includes an input interface  440  for receiving input from the user. For example, in the exemplary embodiment, input interface  440  receives information suitable for use with the methods described herein. Input interface  440  is coupled to processor  420  and may include, for example, a joystick, a keyboard, a pointing device, a mouse, a stylus, a touch sensitive panel (e.g., a touch pad or a touch screen) and/or a position detector. It should be noted that a single component, for example, a touch screen, may function as both presentation interface  430  and as input interface  440 . 
     In the exemplary embodiment, computing device  400  includes a communication interface  450  that is coupled to processor  420 . In the exemplary embodiment, communication interface  450  communicates with at least one remote device, such as power supply  12 , controller  14 , coil  16 , coil  160 , printed circuit board  130 , and/or multilayer printed circuit board  140  (shown in  FIGS. 1-6 ). For example, communication interface  450  may use, without limitation, a wired network adapter, a wireless network adapter and/or a mobile telecommunications adapter. A network (not shown) used to couple computing device  400  to the remote device may include, without limitation, the Internet, a local area network (LAN), a wide area network (WAN), a wireless LAN (WLAN), a mesh network and/or a virtual private network (VPN) or other suitable communication means. 
     The embodiments described herein relate generally to systems and methods and, more particularly, to methods and systems for use in transferring data to and/or power through a multipurpose electrical coil. The embodiments described herein enable information to be transferred and, as such, facilitate reducing hardware and space requirements for electrical control and hardware circuitry on a mobile platform. Additionally, the embodiments described herein facilitate decreasing maintenance costs and/or increasing an overall reliability of the structure. 
     The methods and systems are not limited to the specific embodiments described herein, but rather, components of systems and/or steps of the method may be utilized independently and separately from other components and/or steps described herein. Each method step and/or each component may also be used in combination with other method steps and/or components. Although specific features of various embodiments may be shown in some drawings and not in others, this is for convenience only. Any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing. 
     This written description uses examples to disclose the embodiments, including the best mode, and also to enable any person skilled in the art to practice the embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the disclosure is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. 
     The description of the different illustrative embodiments has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different illustrative embodiments may provide different features as compared to other illustrative embodiments. The embodiment or embodiments selected are chosen and described in order to best explain the principles of the embodiments, the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.