Abstract:
A high-voltage electrical connector system comprises a bushing with a longitudinal axis, a shoulder, a first end, and a second end, wherein the shoulder is between the first end and the second end; a ring arranged circumferentially around a first outside diameter of the bushing, the ring disposed between the shoulder and the second end, the ring including a channel therein defining a circumferential extension extending axially toward the first end; a ground shield disposed on a second outside diameter of the bushing between the ring and the second end, the ground shield comprising one or more of conductive material and semiconductive material; and an insulative portion adjacent the ring and disposed circumferentially over a portion of the ground shield.

Description:
TECHNICAL FIELD 
   The present description relates, in general, to electrical connectors and, more specifically, to electrical connectors with improved insulating features that can help to inhibit flashover. 
   BACKGROUND OF THE INVENTION 
   In underground electrical distribution systems that are energized to, e.g., 15 kV to 35 kV, it is common to employ high-voltage connector assemblies of the elbow/bushing variety. The IEEE STD 386 standard covers such electrical connectors. In their earliest and most basic form, bushing inserts had a squared-off shoulder with no venting and no latch indication, where the shoulder of the bushing is the area where the cuff of the elbow fits against the bushing. Oftentimes, bushing/elbow assemblies allow for connection and disconnection when the line is carrying current (i.e., loadmake and loadbreak operations). 
     FIG. 6  is an illustration of terminator/bushing assembly  600 , which is one prior art embodiment. Assembly  600  includes elbow terminator  610  and bushing insert  620 . Elbow terminator  610  includes sleeve  612 , cuff  611 , and probe  613 . When latched, sleeve  612  fits over bushing insert  620  such that the inner surface of cuff  611  fits snugly up against shoulder  621 , and probe  613  is received into conductive tube  622 . In  FIG. 6 , terminator  610  and bushing insert  610  are not drawn to the same scale. 
   At 25 kV there have been problems in the industry for many years concerning a phenomenon known as partial vacuum-induced flashover. Rarely, when an operator would pull an elbow off of a bushing, there would be an arc from the exposed conductive insert (of the elbow) to a conductive grounding shield on the bushing. It was discovered that flashover is caused by a decrease in the dielectric constant of the air trapped in the assembly due to a partial vacuum during loadbreak operations. In IEEE STD 386 elbow/bushing assemblies, the cuff of the elbow overlaps the collar of the bushing by about ½ inch, so that the first ½ inch of travel during a loadbreak operation creates a volume inside the elbow-bushing interface connection. The volume of air becomes greater without letting any other air enter the assembly, thereby lowering the pressure of the air. When air pressure is lowered, the dielectric strength of that air is also lowered, as described in Paschen&#39;s curve. The lowered dielectric strength of the air leads to lowered resistance and sometimes, arcing. 
   One prior solution to the flashover problem includes the use of additional insulation in the elbow terminator. Such a solution is described in U.S. Pat. No. 5,655,921, which is incorporated by reference herein. Furthermore, U.S. Pat. No. 5,655,921 also shows the use of an insulating layer placed over a grounding shield to prevent flashover. 
   Yet another approach includes decreasing or relieving the partial vacuum as it occurs. One such solution uses a vented bushing insert, which has slots and grooves on its shoulder to allow air to go underneath the cuff of the elbow and relieve the air pocket that is between the cuff of the elbow and the shoulder of the bushing. One problem with that design is that it only vents one of the cavities in which the vacuum is created, while leaving other small cavities unaddressed, e.g., the areas around the nose of the bushing. 
   Another problem with vented bushings is that the vents get plugged up with grease. When linemen put elbows and inserts together, they typically use silicone lubricants to slide the two rubber pieces together. It is an interference fit that is very tight, and the lubrication makes the elbows operable over the next twenty to thirty years. Over time, the lubrication thickens up, turns gluey, and will clog up the vents, making the elbow harder to operate, and pulling more vacuum. More vacuum leads to a greater chance of flashover. An example of a vented shoulder is shown in U.S. Pat. No. 6,939,151. 
   The difference in performance between the insulated elbow solution and the vented bushing solution led to changes in the IEEE standard for testing bushing elbow assemblies. The OIACWT, (Operating Interface AC Withstand Test) provides a way for testing new elbow/bushing designs. There are two tests in the standard—Option A and Option B. Option A is a partial vacuum test at 27.5 kV, with no lubricant, and Option B is a partial vacuum test with aged lubricant at 30.5 kV. 
   A beveled insert is the focus of another solution technique. A beveled insert refers to a bushing insert where the shoulder of the bushing is chamfered. Usually, the shoulder of a bushing is a ninety-degree corner per the IEEE STD 386 standard, but in a beveled insert, the corner is at a much shallower angle, e.g., forty-five degrees. The shallower angle keeps the cuff of the elbow from sealing to the shoulder of the bushing, thereby preventing partial vacuum from occurring. In order to further reduce cuff/shoulder sealing, some beveled inserts include flange-like protrusions that extend radially outward from the beveled surface. 
   Yet another solution includes using a J-ring adjacent to the shoulder of the bushing to relieve the partial vacuum at a short travel distance of the cuff. An example of a J-ring solution is shown in U.S. Pat. No. 7,083,450, which is incorporated by reference herein. J-ring solutions attempt to prevent cuff-shoulder sealing by changing the geometry of the outside surface of the bushing so that the cuff cannot create a seal during loadbreak. The J-ring design is similar to a counterbore design with an added protrusion, an example of which is labeled 115 in FIG. 3 of U.S. Pat. No. 7,083,450. The protrusion prevents the tip of the cuff from sealing along the bottom shelf of the counterbore. Once the tip of the cuff clears the point of the protrusion, it allows air to flow around the cuff of the bushing, thereby relieving any partial vacuum. 
   It is important to note that the J-ring design relieves vacuum differently from the other designs. Vented shoulders and beveled inserts hold the cuff outward to allow air to go underneath the cuff, whereas a J-ring design allows the cuff to fall. Typically, J-ring designs do not succumb to grease pack like vented shoulders do. Further, because so much material is taken away from the insert due to the counterbore, the starting volume of trapped air when the elbow is mated to the insert is much greater than that of the beveled insert and the vented insert. Thus, the pressure drop is not as severe, simply because the starting volume in the steady state latched position is so much greater than the general design. Thus, J-ring solutions provide better vacuum-relieving properties than other currently-available solutions. 
   BRIEF SUMMARY OF THE INVENTION 
   Various embodiments of the invention improve upon J-ring solutions by providing superior insulating properties in order to further reduce the incidents of flashover. For example, some embodiments place a layer of insulating material over a high-electrical-stress portion of a grounding shield adjacent to the J-ring. Areas of high electrical stress include a ridge or point formed by semiconductive material where the semiconductive material abuts the J-ring ring. Sharp ridges or point manipulate electric fields and can attract arcs. By placing a high-electrical-stress area under a layer of insulating material, the embodiment prevents arcing. 
   Other embodiments are directed to methods of making J-ring inserts with improved electrical properties. Some embodiments include manufacturing individual components of a bushing insert, such as a J-ring, a grounding shield, and a housing for the inner conductive parts of the bushing. The components are placed in an injection mold, where insulative rubber is injected to create a non-conductive portion in the space defined by the J-ring, the grounding shield, and the housing for the inner conductive parts. In some embodiments, the layer of insulative material that covers part of the grounding shield is manufactured as a separate component that is placed in the injection mold with the other components. In another example, the J-ring and the insulative layer are manufactured as a single component and placed into the mold with the other components. In yet another example, the grounding shield has holes there that allow the rubber fill to flow therethrough so that the layer of insulating material is formed from the rubber fill. 
   The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a cut-away illustration of an exemplary bushing insert adapted according to one embodiment of the invention; 
       FIG. 1B  shows a more detailed cut-away view of the interface of the various material surrounding the J-ring of  FIG. 1A ; 
       FIG. 2  is an illustration of an exemplary bushing adapted according to one embodiment of the invention; 
       FIG. 3  is an illustration of an exemplary bushing insert adapted according to one embodiment of the invention; 
       FIG. 4  is an illustration of an exemplary bushing adapted according to one embodiment of the invention; 
       FIG. 5  is an illustration of an exemplary bushing adapted according to one embodiment of the invention; 
       FIG. 6  is an illustration of elbow/bushing assembly  600 , which is one prior art embodiment. 
       FIG. 7  is an illustration of elbow/bushing assembly in accordance with a particular embodiment. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1A  is a cut-away illustration of exemplary bushing insert  100  adapted according to one embodiment of the invention. In this example, busing insert  100  is configured to be mated to an elbow terminator (not shown), such as described and illustrated in U.S. Pat. No. 7,083,450, which is hereby incorporated herein by reference. For instance, when completely coupled to a terminator, groove  111  accommodates a latching ring within the terminator, a probe is received within bushing  100  along longitudinal axis  110 , and the cuff of the terminator just covers ring  103 . Bushing insert  100  includes, inter alia, shoulder  107 , grounding shield  101 , ring  103 , and non-conducting portion  102 . 
   Grounding shield  101  operates to keep the outside surface of bushing  101  at ground potential, thereby providing a “dead front” for the safety of operators and others who may come into contact with the high-voltage electrical connector system. In many embodiments, grounding shield  101  is constructed of semiconductive ethylene propylene diene M-class (EPDM) rubber, and thus can conduct electrical charge. Attention is now drawn to  FIG. 1B , which shows a view of a portion of bushing  100  of  FIG. 1A .  FIG. 1B  shows a more detailed cut-away view of the interface of the various material surrounding J-ring  103 . In this example, J-ring  103  includes axial protrusion  105  and trough  106 . In  FIG. 1B , there is a high-stress area where J-ring  103 , grounding shield  101 , and insulative portion  104  come together. Semiconductive material  101  comes to a point or ridge at this high-stress area. The present example embodiment overlays the high-stress point with insulative portion  104 , thereby preventing arcing at voltages as high as 30.5 kV or higher. 
   The area where grounding shield  101  and insulative portion  104  come together at the outside surface of bushing insert  100  is a lower stress area. The axial extent of insulative portion  104  from J-ring  103  along the outside surface can be adjusted to eliminate the possibility of arcing. Specifically, the farther this lower-stress point is away from shoulder  107 , the less the likelihood of an arc being able to form from the terminator probe (not shown) to grounding shield  101 . For 25 kV and 30 kV applications of the IEEE STD 386 standard, a length of insulating portion  104  between ¼ inch and ⅝ inch is adequate to eliminate all or nearly all of the risk of flashover. In the various embodiments shown herein, the thickness of insulative portion  104  can be adapted for the specific use and may be influenced by factors such as operating voltage, material, and the like. For most IEEE STD 386 embodiments using molded thermoset plastic, a thickness of a tenth of an inch is adequate. 
   Prototypes tested showed unexpectedly positive results. For instance, Table 1 shows results of the OIACWT for crude, hand-made prototypes of the bushing insert shown in  FIG. 1A , with nylon J-rings and semiconductive EPDM grounding shields. There are two groupings made with respect to cracks in the J-rings. One group “Cracks Included” includes prototypes tested that were confirmed to have very small cracks in their respective J-rings. “Cracks Culled” shows the same prototype set but without the data from bushings that included J-ring cracks. Table 1 shows that when an insert has a J-ring for vacuum relief but no other insulation, there was about a 20% pass rate for OIACWT option B. Furthermore, while not shown in the chart, merely including about ¼ inch of insulation over the end of a grounding shield of a bushing (without a J-ring) is expected to provide about a 0-5% passing rate for OIACWT option B. Since a J-ring alone provides about 20% success, and since insulation alone provides 0-5% success, one would expect a J-ring with added insulation (as shown in  FIG. 1B ) would provide between 20% and 25% success in OIACWT option B. However, Table 1 shows that a crude J-ring prototype with added insulation can be expected perform with about 90% success. Carefully manufactured bushing inserts can be expected to improve the approximately 90% success rate to at or near 100%. Thus, when paired together, a J-ring and grounding shield insulator exhibit synergy. 
   
     
       
             
             
             
             
             
             
             
             
             
             
           
             
           
             
             
             
             
             
             
             
             
             
             
           
             
           
             
             
             
             
             
             
             
             
             
             
           
         
             
               TABLE 1 
             
             
                 
             
             
                 
                 
               30.5 kV 
               % 
                 
               27.5 kV 
               % 
                 
               24.5 kV 
               % 
             
             
               Design 
               Attempted 
               Pass 
               Pass 
               Attempted 
               Pass 
               Pass 
               Attempted 
               Pass 
               Pass 
             
             
                 
             
           
           
             
                 
             
           
        
         
             
               Cracks Included 
             
           
        
         
             
               Recessed 
               5 
               1 
               20% 
               11 
               2 
               18% 
               0 
               0 
               — 
             
             
               Groove no 
             
             
               insulation 
             
             
               Recessed 
               2 
               0 
                0% 
               17 
               12 
               71% 
               8 
               8 
               100% 
             
             
               Groove 
             
             
               0.25″ 
             
             
               insulation 
             
             
               Recessed 
               13 
               12 
               92% 
               12 
               10 
               83% 
               3 
               3 
               100% 
             
             
               Groove 
             
             
               0.625″ 
             
             
               insulation 
             
           
        
         
             
               Cracks Culled 
             
           
        
         
             
               Recessed 
               5 
               1 
               20% 
               11 
               2 
               18% 
               0 
               0 
               — 
             
             
               Groove no 
             
             
               insulation 
             
             
               Recessed 
               0 
               0 
               — 
               14 
               12 
               86% 
               8 
               8 
               100% 
             
             
               Groove 
             
             
               0.25″ 
             
             
               insulation 
             
             
               Recessed 
               13 
               12 
               92% 
               11 
               10 
               91% 
               3 
               3 
               100% 
             
             
               Groove 
             
             
               0.625″ 
             
             
               insulation 
             
             
                 
             
           
        
       
     
   
   Manufacturing bushing insert  100 , in some embodiments, starts by making the components that, together, form bushing insert  100 . A shield housing (not shown) houses the current-carrying parts of bushing  100 , such as aluminum contact tube  120  that mates with the probe of the terminator. The shield housing is molded out of rubber. J-ring  203  is also made usually by molding, as is grounding shield  101  and insulative portion  104 . The components are placed in an injection mold, where non-conducting rubber is injected into the space defined between the shield housing and the other components (J-ring  103 , grounding shield  101 , and insulative portion  104 . For the example embodiments herein, J-rings can be made of any of a variety of materials, including, e.g., plastic, fiberglass, nylon, thermoset plastic, thermal plastic rubber (TPR), thermal plastic elastomer (TPE) and the like. 
     FIG. 2  is an illustration of exemplary bushing  200  adapted according to one embodiment of the invention. Specifically,  FIG. 2  is a detailed cut-away view showing the various materials and layers in proximity to J-Ring  203 . In addition to J-ring  203 , bushing insert  200  also includes insulative portion  204 , first grounding shield portion  205 , second grounding shield portion  201 , and insulating rubber  202 . 
   In bushing  200 , the grounding shield is made of two parts (i.e., portions  201  and  205 ), which in this example are of different materials, though in other embodiments the grounding shield may be of the same or similar materials. The IEEE STD 386 standard requires that the conductive collar (of the grounding shield) be within a prescribed distance of shoulder (e.g.,  207 ) of a bushing. The purpose of having the grounding shield close to the shoulder is to keep the dead front shell as long as possible for safety and to keep the electric field lines from escaping outside the bushing and making things hotter electrically. In the bushing of  FIG. 1A , to fit J-ring in  103 , conductive collar  101  is moved away from shoulder  107  to make room for J-ring  103 . In other words, the design of  FIG. 1A  may not meet the shielding specification set forth in the IEEE STD 386 standard. Bushing insert  200  of  FIG. 2  seeks to comply with the standard by disposing the conductive grounding shield so that it extends axially to a point very close to shoulder  207 . 
   Also, the design of  FIG. 2  shields the trough of J-ring  203  electrically from partial discharge. In  FIG. 2 , the ground plane formed by portions  201  and  205  goes under J-ring  203  and almost fully shields the entire length of J-ring  203 . From the perspective of the trough, the nearest energized part is in the center of bushing  200  (not shown), which is separated from the trough by grounding shield portion  205 . As a result, the electric field lines go from the energized parts of the insert (in the center of bushing  200  and not shown herein) toward the ground plane and stop there so that the electric filed lines do not penetrate into the air gap. Furthermore, as with the embodiment of  FIG. 1 , the ground plane is covered partially by insulative material (in this case, insulative portion  204 ) to inhibit flashover. The length of insulative portion  204  “L” can be adapted to a variety of applications, and can be around, e.g., ¼ inch to ⅝ inch for a bushing conforming to the IEEE STD 386 standard. 
   Similar to the embodiment of  FIG. 1A , manufacturing bushing insert  200 , in some embodiments, starts by making the components that form bushing insert  200 . The shield housing is molded out of rubber. First grounding shield portion  205  is over-molded on J-ring  203  to create a bond between the materials. In this example, first grounding shield portion  205  is made of a black semiconductive plastic, such as carbon-loaded plastic or nylon, metal-loaded plastic, and/or the like. Also, second grounding shield portion  201  is made by molding, e.g., semiconductive EPDM. Second grounding shield portion  201  is then snapped to the component that includes J-ring  203  and first grounding shield portion  205  using, e.g., interlocking tabs where portions  201  and  205  contact. The snap-on operation makes a component that includes J-ring  203 , as well as the entire semiconductive grounding shield. 
   After the snap-on operation, the snapped-together component and the shield housing are placed into a mold. The mold injects insulative rubber into the space defined by the shield housing and the snapped-together component. The insulative rubber forms non-conductive portion  202  and bonds to portions  201  and  205  as well as to J-ring  203 . In some embodiments, insulative portion  204  is independently molded as a piece of black insulative plastic to slide into place over the outside diameter bushing  200 . This can be done before or after non-conductive portion  202  is molded. 
   Alternatively, some embodiments provide for a plurality of holes in grounding shield portion  205 , represented by arrows in  FIG. 2 . The holes allow the insulative rubber of portion  202  to flow therethrough during injection, thereby forming insulative portion  204  out of rubber during the molding process. 
     FIG. 3  is an illustration of exemplary bushing insert  300  adapted according to one embodiment of the invention. Specifically,  FIG. 3  provides a detailed, cut-away view of bushing  300 , showing the materials therein. The embodiment of  FIG. 3  is somewhat similar to the embodiment of  FIG. 2 ; however, bushing  300  utilizes single-piece grounding shield  301 . The length of insulative portion  304  “L” can be adapted to a variety of applications, and can be around, e.g., ¼ inch to ⅝ inch for a bushing conforming to the IEEE STD 386 standard. The embodiment of  FIG. 3  performs electrically in the same way that the embodiment of  FIG. 2  performs, as described above. 
   Bushing  300  can be manufactured, e.g., by making J-ring  303 , grounding shield  301 , and internal shield housing (not shown) separately, then those pieces are put into an injection mold. In this example, grounding shield  301  includes a plurality of holes represented as arrows that let the insulative fill plastic flow therethrough. The fill insulation passes through the holes in grounding shield  301  to form insulative portion  304 . The insulative fill rubber also forms non-conductive portion  302 . 
     FIG. 4  is an illustration of exemplary bushing  400  adapted according to one embodiment of the invention. Specifically,  FIG. 4  is a detailed, cut-away view showing the materials inside bushing  400 . Bushing  400  provides insulative portion  404 , which is adjacent to J-ring  403  and covers a portion of grounding shield  401 . Bushing  400  does not include grounding underneath J-ring  403  and proximate shoulder  407 , but does provide ease of manufacture. 
   Bushing  400  includes separate cuff  404  that can be made of molded rubber, plastic, or other insulative material. In one example, cuff  404 , J-ring  403 , grounding shield  401 , and the housing shield (not shown) are independently made and arranged in a fill mold. Then insulative rubber is injected into the mold, thereby creating non-conductive portion  402 . In one example, during the injection molding process, the insulative rubber is hot and not vulcanized. As the insulative rubber, J-ring  403 , rubber cuff  404 , and grounding shield  401  are exposed to heat, the insulative rubber forms molecular bonds with the materials of J-ring  403 , rubber cuff  404 , and grounding shield  401 . The bonding between the materials creates a seal that prevents arcing between the probe of the terminator and grounding during a partial vacuum condition. The length of insulative portion  404  “L” can be adapted to a variety of applications, and can be around, e.g., ¼ inch to ⅝ inch for a bushing conforming to the IEEE STD 386 standard. 
     FIG. 5  is an illustration of exemplary bushing  500  adapted according to one embodiment of the invention. Specifically,  FIG. 5  shows a detailed, cut-away view of a portion of bushing  500  in order to illustrate the grounding properties of one embodiment. Bushing  500  includes grounding shield  501 , J-ring  503 , insulative portion  504 , and non-conductive portion  502 . Grounding shield  501  extends axially almost up to shoulder  507  and provides IEEE STD 386-specified grounding. In bushing  500 , the material of insulative portion  504  bonds with the material of J-ring  503  to provide a seal that withstands partial vacuum and prevents arcing. 
   In one example, bushing  500  is made using the following process. The various components are made individually. For instance, J-ring  503  is molded. J-ring  503  is then placed into a mold, where screw-ram injection is used to mold the insulating plastic of insulative portion  504 . During the molding process, J-ring  503  and insulative portion  504  are bonded together to make, in effect, one physical piece. Then, the portion that includes pieces  503  and  504  is placed in a fill mold along with grounding shield  501  and a housing shield (not shown). Then, insulative rubber is screw-ram injected to form non-conducting portion  502 . The rubber of non-conducting portion  502  bonds to J-ring  503  and to grounding shield  501 . The length of insulative portion  504  “L” can be adapted to a variety of applications, and can be around, e.g., ¼ inch to ⅝ inch for a bushing conforming to the IEEE STD 386 standard. 
   In an alternate embodiment, J-ring  503  and insulative portion  504  are made of one piece of plastic, e.g., yellow insulating plastic. After fill molding has been performed, the length “L” is painted black so that the yellow of J-ring  503  contrasts with the surrounding colors and performs its latch indication function. 
     FIG. 7  is an illustration of terminator/bushing assembly that includes elbow connector  710  and bushing insert  100 . Bushing insert  100  has been previously described. Elbow connector  710  includes sleeve  712 , cuff  711 , and probe  713 . When elbow connector  710  and bushing insert  100  are latched, elbow connector  710  interfaces with bushing insert  100  to make an electrical connection therewith. Sleeve  712  and cuff  711  of elbow connector  710  fit over an end of bushing insert  100  such that when bushing insert  100  and elbow connector  710  are completely coupled, cuff  711  fits snugly over J-ring  103 . In a particular embodiment, J-ring  103  is disposed on an outside diameter of bushing insert  100  adjacent a shoulder of bushing insert and  100 , J-ring  103  defines in part an air chamber  720  with cuff  711  when bushing insert  100  and elbow terminator  710  are completely coupled. 
   While the description herein has given examples of specific materials that may be used in various embodiments of the invention, it should be noted that other suitable materials can also be used. For instance, instead of EPDM rubber, some embodiments may use TPR or TPE, silicone rubber, epoxy, and/or the like. Moreover, dimensions given herein are for example only and should not be seen as limiting. Furthermore, while the embodiments herein have been described with respect to the IEEE STD 386 standard, embodiments of the invention can differ from the standard in many different respects. In fact, any high-voltage bushing that receives a probe from a terminator can be adapted according to the principles described herein. 
   Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.