Abstract:
One embodiment of the present invention is a unique gas turbine engine system. Another embodiment is a unique exhaust nozzle system for a gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engine systems and exhaust nozzle systems for gas turbine engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. national counterpart application of international application serial No. PCT/US2012/053777 filed Sep. 5, 2012, which claims priority under 35 USC §119(e) to U.S. Provisional Patent Application No. 61/532,298 filed Sep. 8, 2011, the entire disclosures of which are incorporated herein by reference. 
    
    
     GOVERNMENT RIGHTS 
     The present application was made with the United States government support under Contract No. NNC10CA02C, awarded by NASA. The United States government may have certain rights in the present application. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to gas turbine engines, and more particularly, to gas turbine engine systems and supersonic nozzles for gas turbine engine systems. 
     BACKGROUND 
     Gas turbine engine systems and exhaust nozzle systems for gas turbine engines that effectively provide thrust in subsonic, transonic and supersonic flight regimes, with reduced noise output during certain operations, remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology. 
     SUMMARY 
     One embodiment of the present invention is a unique gas turbine engine system. Another embodiment is a unique exhaust nozzle system for a gas turbine engine. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for gas turbine engine systems and exhaust nozzle systems for gas turbine engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
         FIG. 1  schematically depicts some aspects of a non-limiting example of a variable cycle aircraft gas turbine engine in accordance with an embodiment of the present invention. 
         FIG. 2  is a sectional view illustrating some aspects of a non-limiting example of a supersonic converging-diverging nozzle in accordance with an embodiment of the present invention. 
         FIG. 3  is a partial isometric sectional view illustrating some aspects of a non-limiting example of a supersonic converging-diverging nozzle in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     For purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the invention is intended by the illustration and description of certain embodiments of the invention. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present invention. Further, any other applications of the principles of the invention, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the invention pertains, are contemplated as being within the scope of the present invention. 
     Referring now to the drawings, and in particular,  FIG. 1 , some aspects of a non-limiting example of a gas turbine engine system  10  in accordance with an embodiment of the present invention are schematically depicted. In one form, gas turbine engine  10  is a variable cycle engine. In other embodiments, gas turbine engine  10  may not be a variable cycle engine. In one form, gas turbine engine  10  is an aircraft engine, and in particular, a turbofan engine. However, it will be understood that in other embodiments, engine  10  may be any other type of gas turbine engine. In still other embodiments, engine  10  may be a combined cycle engine. 
     Engine  10  includes a gas generator  12 , a low pressure (LP) turbine  14 , an adaptive fan  16 , an LP shaft  18  and an exhaust nozzle system  20 , such as a variable exhaust system having one or more variable nozzles. In one form, adaptive fan  16  is powered by LP turbine  14  via LP shaft  18 . In other embodiments, adaptive fan  16  may be powered by other turbines in addition to or in place of LP turbine  14 . Adaptive fan  16  is a turbofan system and drive system configured to operate one or more turbofan stages at at least two different speeds relative to the turbine(s) and/or shaft(s) that supply power to the drive system and turbofan system. In some embodiments, a conventional turbofan may be employed in addition to or in place of adaptive fan  16 . 
     Gas generator  12  includes a compressor  22 , a combustor  24 , a high pressure (HP) turbine  26  and an HP shaft  28 . Compressor  22  includes a plurality of compressor stages (not shown), and is coupled to HP turbine  26  via HP shaft  28  in a driving arrangement. Compressor  22  is configured to pressurize the airflow received at its inlet from adaptive fan  16 . Some of the compressor discharge air and/or interstage air pressurized by compressor  22  may be supplied to other engine  10  components, e.g., turbine wheels, blades and vanes, for cooling. In addition, some of the compressor discharge air and/or interstage air pressurized by compressor  22  may be provided in the form of customer bleed air, e.g., for use by the aircraft environmental control systems, as well as for use in active lift surfaces and control surfaces of the aircraft, e.g., to maintain desirable airflow characteristics of such surfaces under varying flight conditions. 
     Combustor  24  is in fluid communication with compressor  22 , and is structured to combust a mixture of fuel and compressor discharge air received from compressor  22 . HP turbine  26  is in fluid communication with combustor  24 , and is operative to receive the hot gases discharged by combustor  24 , and to extract power therefrom for driving compressor  22 . Engine core flowpath gases exiting HP turbine  26  are directed into LP turbine  14 , which extracts mechanical power from the hot working airflow to drive adaptive fan  16 . LP shaft  18  is coupled to LP turbine  14 , and is configured to receive and transmit the mechanical power from LP turbine  14  to adaptive fan  16 . 
     Adaptive fan  16  includes a base fan  30  and a variable-speed fan  32 , both of which are powered by LP turbine  14  via LP shaft  18 . It will be noted that in other embodiments of the present invention, depending on the configuration and/or installation of engine  10 , another base rotating load in addition to or in place of base fan stage  30  may be employed, and another variable-speed rotating load in addition to or in place of variable-speed fan stage  32  may be employed. Examples of other base rotating loads include, but are not limited to, generators, pumps, gearboxes and compressors, the latter including one or more engine  10  core and/or intermediate compressors and/or engine  10  driven equipment. Examples of other variable-speed rotating loads include, but are not limited to, generators, pumps, gearboxes, one or more boost compressors, and/or may be one or more stages of a core and/or intermediate compressor, e.g., powered by HP shaft  28  and/or another turbine via a transmission system, such as that described herein, which is configured to vary the speed of the variable-speed rotating load. 
     In one form, base fan  30  includes a single rotating fan stage. In other embodiments, base fan  30  may include more than one fan stage. In one form, variable-speed fan  32  includes one rotating fan stage. In other embodiments, variable-speed fan  32  may include more than one rotating fan stage. 
     It will be understood that the term, “variable-speed,” as applied to variable-speed fan  32 , does not imply that the base rotating load, which in the present embodiment base fan  30 , is limited to rotation at a single speed. Rather, the term, “variable-speed” is meant to indicate that the variable-speed load, which in the present embodiment is variable-speed fan  32 , has a speed that is variable, in particular, variable relative to the speed of the base rotating load, e.g., base fan  30 . 
     A portion of the airflow exiting base fan  30  is directed into a bypass duct  34  for directly providing thrust via exhaust nozzle system  20 , and the balance is directed to variable-speed fan  32 . A portion of the airflow exiting variable-speed fan  32  is directed into a bypass duct  36  for directly providing thrust via exhaust nozzle system  20 , and the balance is directed into compressor  22  as core airflow, which provides thrust via exhaust nozzle system  20  after exiting LP turbine  14 . 
     In one form, adaptive fan  16  is powered by LP turbine  14  via LP shaft  18 , as previously mentioned. In one form, base fan  30  is coupled directly to LP shaft  18  and driven thereby, whereas variable-speed fan  32  is coupled to LP shaft  18  via an intervening transmission system  38 , and hence is powered indirectly by LP shaft  18  via transmission system  38 . In the present embodiment, transmission system  38  is configured to selectively vary the speed of variable-speed fan  32 , e.g., relative to the speed of base fan  30 . In other embodiments, fan  32  may not be powered by a transmission, e.g., transmission system  38 , but rather, may be powered directly by LP shaft  18  or HP shaft  28 . In still other embodiments, fan  16  may be a conventional fan having one or more stages operating at the same speed. 
     The gas flow discharged by LP turbine  14  is an engine core flow, and is referred to herein as a first stream flow. The first stream flow is discharged from LP turbine  14  around an engine tailcone  40 . The air flow discharged by fan  32  into bypass duct  36  is a bypass flow, and is referred to herein as a second stream flow. The air flow discharged by fan  30  into bypass duct  34  is also a bypass flow, and is referred to herein as a third stream flow. That is, in the embodiment depicted in  FIG. 1 , engine  10  discharges into exhaust nozzle system  20  three distinct flow streams: the first stream flow, second stream flow and third stream flow mentioned above. In other embodiments, engine  10  may only discharge two flow streams into exhaust nozzle system  20 , e.g., a core flow and a single bypass flow, or may discharge into exhaust nozzle system  20  any number of flow streams. 
     Under some operating conditions, for example, low aircraft speed subsonic operating conditions, such as take-off, approach, cut-back, landing and/or other low speed near-ground or on-ground operations, it is desirable to reduce the noise generated by engine  10 . One way of reducing noise during such operations is to reduce the velocity or the exhaust stream discharged by exhaust nozzle system  20 . In one form, exhaust nozzle system  20  includes an ejector to entrain ambient free stream air (i.e., air from outside of engine  10 , e.g., air inside or outside of the nacelle, housing or other structure into which engine  10  is installed) into the first stream flow, second stream flow and/or third stream flow in order to reduce the velocity of the exhaust stream discharged by exhaust nozzle system  20 . 
     Referring now to  FIGS. 2 and 3 , some aspects of a non-limiting example of exhaust nozzle system  20  in accordance with an embodiment of the present invention are illustrated. The illustrations of  FIGS. 2 and 3  are sectional in nature, and only illustrate a portion of many of the components identified herein, e.g., approximately 90 degrees of rotation for circular or elliptical components. It will be understood by those of ordinary skill in the art that an actual an nozzle system  20  would extend to 360 degrees of rotation. 
     In one form, exhaust nozzle system  20  is a supersonic converging-diverging nozzle. In other embodiments, exhaust nozzle system  20  may not be a supersonic converging-diverging nozzle. Exhaust nozzle system  20  includes a mixer  50 , a nozzle  54 , a nozzle  58 , an inner flowpath  62 , a middle flowpath  66 , an outer flowpath  70 , an ejector  74  and an ejector  78 . In one form, exhaust nozzle system  20  is configured to discharge the third stream flow with entrained ambient free stream air, and mixed first stream flow and second stream flow. In other embodiments, exhaust nozzle system  20  may be configure to discharge only two flow streams with or without entrained ambient free steam air, or any other number of flow streams with or without entrained ambient free steam air. 
     Mixer  50  is configured to mix the first stream flow and the second stream flow. Mixer  50  is positioned upstream of nozzle  54 . In other embodiments, mixer  50  may be configured to mix other flow streams. In one form, mixer  50  is a forced mixer. In other embodiments, mixer  50  may not be a forced mixer. For example and without limitation, in various embodiments, mixer  50  may be a chevron mixer or a simple splitter that allows the first stream flow and the second stream flow to mix, e.g., confluent flow mixing. In one form, mixer  50  is a lobed mixer. In other embodiments, mixer  50  may take other forms. In one form, mixer  50  is fixed. In other embodiments, mixer  50  may be a variable mixer, e.g., moveable between different positions and configured to vary the mixing length and/or the bypass ratio as between the second stream flow and the first stream flow and/or between other flow streams. Still other embodiments may not employ a mixer. 
     In one form, nozzle  54  is positioned downstream of mixer  50 . In other embodiments, nozzle  54  may be positioned upstream of mixer  50 . In one form, nozzle  54  is a converging nozzle configured to accelerate and discharge the mixed first stream flow and second stream flow. The length of nozzle  54  may vary with the needs of the application, e.g., to achieve a desired exhaust plume shape. In one form, nozzle  54  has a circular throat. In other embodiments, the throat of nozzle  54  may be another shape, e.g., elliptical, rectangular or any other suitable shape. 
     Nozzle  58  is disposed downstream of nozzle  54 . Nozzle  58  is configured to receive, accelerate and discharge the mixed first stream flow and second stream flow. In one form, nozzle  58  is a variable nozzle. In other embodiments, nozzle  58  may be a fixed nozzle. In one form, nozzle  58  is configured as a diverging nozzle. In other embodiments, nozzle  58  may be configured as a converging nozzle, or as a nozzle operative to selectively function as a converging nozzle and a diverging nozzle. In some embodiments, nozzle  58  may be a converging diverging nozzle. In a particular form, nozzle  58  is configured as a variable diverging nozzle having a variable divergence angle. In one form, nozzle  58  is formed of a two flaps  84  positioned opposite each other. In other embodiments, any number of flaps or other structures may be employed. In still other embodiments, nozzle  58  may take other forms. In one form, flaps  84  are pivotably attached to a side wall  82 , e.g., of an engine nacelle, and are each configured to pivot about a pivot point  86  in order to vary the divergence angle of nozzle  58 . In one form, flaps  84  are arcuate. In other embodiments, flaps  84  may be linear, e.g., flat. In various embodiments, flaps  84  may take any suitable shape. In one form, flaps  84  are configured to rotate to approximately 0° divergence angle for use during low speed operations, and to approximately 10° divergence angle for high sonic, transonic and supersonic flight operations. In other embodiments, other angles may be employed. In still other embodiments, flaps  84  may be configured for other forms of motion, e.g., translation, alone or in combination with rotation, in order to vary the divergence angle. 
     Inner flowpath  62  is in fluid communication with the discharge of LP turbine  14 , and is operative to receive and conduct the pressurized gases discharged by LP turbine  14  (first stream flow). Inner flowpath  62  is formed between tailcone  40  and mixer  50 . Middle flowpath  66  is in fluid communication with bypass duct  36 , and is operative to receive and conduct pressurized air discharged by fan  32  (second stream flow). Middle flowpath  66  is formed between mixer  50  and a wall  90  extending from nozzle  54 . Outer flowpath  70  is in fluid communication with bypass duct  34 , and is operative to receive and conduct pressurized air discharged by fan  30  (third stream flow). Outer flowpath  70  is formed between wall  90  and a nozzle exterior wall  94 . 
     Ejector  74  is configured to entrain ambient free stream air into the third flow stream received via outer flowpath  70  to form a mixed flow including both the ambient free stream air and the third stream flow. In some embodiments, ejector  74  is also configured to form a thrust reverser. In other embodiments, ejector  74  may not form a thrust reverser. In one form, ejector  74  includes two ejector doors  98 . In other embodiments, ejector  74  may take other forms and/or may include any number of ejector doors. In one form, ejector doors  98  are arcuate. In other embodiments, ejector doors may be linear, e.g., flat. In various embodiments, ejector doors  98  may take any suitable shape. In one form, ejector doors  98  are variable-position doors, e.g., doors that are configured to be moved by one or more actuation systems (not shown) into more than one position. In one form, ejector doors  98  are configured to vary the amount of ambient free stream air entrained into the other flow stream, e.g., by changing positions. 
     In one form, each ejector door  98  is pivotably attached to side wall  82  (and/or one or more other structures in other embodiments), and is configured to pivot about a pivot point  102  in order to vary its position. In other embodiments, ejector doors  98  may be configured for other forms of motion, e.g., translation, alone or in combination with rotation. Ejector doors  98  are configured to selectively form and vary a gap between nozzle exterior wall  94  (and/or other structures in other embodiments) and ejector doors  98 . By varying the position of ejector doors  98 , ejector doors  98  are configured to selectively vary the gap between nozzle exterior wall  94  (and/or other structures in other embodiments) and ejector doors  98 , and hence vary the amount of ambient air entrained into the third flow stream (or one or more other flow streams in other embodiments). The size of the gap at a particular angle of ejector doors  98  may vary with the needs of the application. In one example, approximately 10° or less of rotation of ejector doors  98  has been found suitable for entraining a sufficient amount of ambient air at take-off conditions and other near-ground operations to meet desired noise reduction goals. The amount of rotation may vary with the needs of the application. In some embodiments, ejector doors  98  may be selectively rotated a larger amount, e.g., 30-60 degrees, in order to form a thrust reverser. In other embodiments, ejector doors  98  may be rotated or otherwise moved to greater or lesser degrees in order to form a thrust reverser. 
     In one form, ejector doors  98  are also configured to selectively prevent the entrainment of the ambient free stream air. In other embodiments, ejector doors  98  may not be configured to selectively prevent the entrainment of the ambient free stream air. In one form, ejector doors  98  are configured to selectively prevent the entrainment of the ambient free stream air by moving into a position that closes the gap between nozzle exterior wall  94  (and/or other structures in other embodiments) and ejector doors  98 . In other embodiments, ejector doors  98  may be configured to selectively prevent the entrainment of the ambient free stream air via other means. 
     In addition, in some embodiments, ejector doors  98  are configured to form a nozzle  106  in addition to forming an ejector. For example, in the depiction of  FIG. 2 , a counterclockwise rotation of the depicted ejector door  98  would eventually result in closing the gap between ejector door  98  and wall  94 ; in some embodiments, ejector doors  98  are configured to form a diverging nozzle when in the closed position. Rotation in the clockwise direction of the depicted ejector door  98  would result in a reduction in the divergence angle, and continued rotation in the clockwise direction would yield ejector door  98  to be at a converging angle, hence forming, in conjunction with the other ejector door  98 , a converging nozzle. Thus, at low speed operation, wherein it is desirable to entrain ambient free stream air in order to reduce noise, ejector doors  98  also form a converging nozzle in some embodiments. At high speed operation, ejector doors  98  would be rotated in the opposite direction to form a diverging nozzle, and reducing or eliminating the entrainment of ambient free stream air. Hence, in some embodiments, ejector doors  98  are configured to selectively form nozzle  106  as a converging or a diverging nozzle. In one form, nozzle  106  is formed in part by the shape of the exterior surfaces of nozzle  58 , in conjunction with the interior surfaces of ejector doors  98 . In other embodiments, nozzle  106  may be formed by ejector doors  98  alone. 
     In one form, ejector  78  is disposed inward of ejector  74 , and is configured to entrain air from the mixed flow in outer flowpath  70  into the flow stream discharged by the nozzle  54 . In other embodiments, ejector  78  may be configured to entrain air from the third stream flow in flowpath  70 , e.g., upstream of ejector  74 , or to entrain air from one or more other sources. In one form, ejector  78  is formed by nozzle  58 , by changing its position (the positions of flaps  84 ) to form a gap between nozzle  58  and nozzle  54 , e.g., the aft surface of nozzle  54 . In other embodiments, ejector  78  may be formed by other structures. In one form, ejector  78  is a variable ejector configured to vary the amount of air entrained into the flow stream discharged by nozzle  54 , e.g., by varying the position of flaps  84  to vary the gap between flaps  84  and nozzle  54 . In other embodiments, ejector  78  may not be a variable ejector. In one form, ejector  78  is configured to selectively close and prevent entrainment of air from the mixed flow or third stream flow, e.g., by changing the position of flaps  84  to engage the aft surface of nozzle  54 , thereby closing the gap between nozzle  58  and nozzle  54 . 
     Embodiments of the present invention include a gas turbine engine system, comprising: a fan system; a compressor system in fluid communication with the fan system; a combustion system in fluid communication with the compressor system; a turbine system in fluid communication with the combustion system, wherein the turbine system is configured to discharge a first stream flow in the form of an engine core flow; and wherein the fan system is configured to discharge a second stream flow in the form of a bypass flow and to discharge a third stream flow in the form of an other bypass flow; and a exhaust nozzle system in fluid communication with the fan system and the turbine system, including: a first nozzle configured to discharge the first stream flow and the second stream flow; and an ejector configured to entrain ambient free stream air into the third stream flow. 
     In a refinement, the exhaust nozzle system is configured to discharge the third stream flow with entrained ambient free stream air, and the first stream flow and the second stream flow. 
     In another refinement, the exhaust nozzle system includes a mixer configured to mix the first stream flow and the second stream flow. 
     In yet another refinement, the ejector includes a plurality of ejector doors. 
     In still another refinement, the ejector doors are variable-position doors. 
     In yet still another refinement, the ejector doors are configured to vary an amount of ambient free stream air entrained into the third stream flow. 
     In a further refinement, the ejector doors are configured to close and prevent entrainment of ambient free stream air. 
     In a yet further refinement, the ejector doors are configured to selectively form a thrust reverser. 
     In a still further refinement, the ejector doors are configured to form a second nozzle. 
     In a yet still further refinement, the second nozzle is configured to selectively form a converging nozzle or a diverging nozzle. 
     In an additional refinement, the exhaust nozzle system is configured as a supersonic nozzle system. 
     In another additional refinement, the exhaust nozzle system includes a third nozzle configured to discharge the first stream flow and the second stream flow. 
     In yet another additional refinement, the third nozzle is configured as a variable nozzle. 
     In still another additional refinement, the variable nozzle is configured as a variable diverging nozzle having a variable divergence angle. 
     In yet still another additional refinement, the first nozzle is a converging nozzle. 
     Embodiments of the present invention include an exhaust nozzle system for a gas turbine engine, comprising: 
     a first nozzle configured to discharge a flow stream of the gas turbine engine, wherein the first nozzle is a converging nozzle; and 
     a first ejector in fluid communication with an other flow stream discharged by the gas turbine engine and configured to entrain ambient free stream air into the other flow stream to form a mixed flow, wherein the first ejector is also configured to form a thrust reverser. 
     In a refinement, the first ejector includes a plurality of variable-position ejector doors. 
     In another refinement, the ejector doors are configured to vary an amount of ambient free stream air entrained into the other flow stream. 
     In yet another refinement, the ejector doors are configured to close and prevent entrainment of ambient free stream air. 
     In still another refinement, the ejector doors are configured to selectively form a thrust reverser. 
     In yet still another refinement, the ejector doors are configured to form a second nozzle. 
     In a further refinement, the second nozzle is configured to selectively form a converging nozzle or a diverging nozzle. 
     In a yet further refinement, the wherein the flow stream is a combination of an engine core flow and a first bypass flow stream, and wherein the other flow stream is a second bypass flow stream different from the first bypass flow stream. 
     In a still further refinement, the exhaust nozzle system further comprises a third nozzle configured to discharge the flow stream. 
     In a yet still further refinement, the third nozzle is a diverging nozzle. 
     In an additional refinement, the third nozzle is configured as a variable nozzle. 
     In another additional refinement, the variable nozzle is configured as a variable divergent nozzle having a variable divergence angle. 
     In yet another additional refinement, the exhaust nozzle system further comprises a second ejector disposed inward of the first ejector, wherein the second ejector is configured to entrain air from the mixed flow or the other flow stream into the flow stream discharged by the first nozzle. 
     In still another additional refinement, the second ejector is formed by a third nozzle, wherein the third nozzle is disposed downstream of the first nozzle. 
     In yet still another additional refinement, the second ejector is configured as a variable ejector. 
     In the second ejector is also configured to close and prevent entrainment of the air from the mixed flow or the other flow stream. 
     In another refinement, the first nozzle is a converging nozzle. 
     In yet another refinement, the flow stream is a combination of an engine core flow and a first bypass flow stream, further comprising a mixer disposed upstream of the first nozzle and configured to mix the engine core flow and the first bypass flow stream. 
     Embodiments of the present invention include a gas turbine engine system, comprising: a fan system; a compressor system in fluid communication with the fan system; a combustion system in fluid communication with the compressor system; a turbine system in fluid communication with the combustion system, wherein the turbine system is configured to discharge a first stream flow in the form of an engine core flow; and wherein the fan system is configured to discharge a second stream flow in the form of a bypass flow and to discharge a third stream flow in the form of an other bypass flow; and an exhaust nozzle system in fluid communication with the fan system and the turbine system, including: means for discharging the first stream flow, the second stream flow and the third stream flow, including means for reversing thrust of the gas turbine engine system. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the invention, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary.