Patent Publication Number: US-2022218897-A1

Title: Single actuated precision dose intermediate pumping chamber

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application No. 63/135,081, filed Jan. 8, 2021, the contents of which are incorporated herein by reference in their entirety. 
    
    
     TECHNICAL FIELD 
     The disclosed examples generally relate to medication delivery. More particularly, the disclosed examples relate to techniques, processes, systems, and pump devices for providing a fixed volume of fluid, which is delivered and refilled within one pumping cycle. 
     BACKGROUND 
     Many drug delivery devices include a reservoir for storing a liquid drug and a pump mechanism that is operated to expel the stored liquid drug from the reservoir for delivery to a user. The pump mechanism may be a positive displacement pump that pushes a dose of drug from a reservoir and through valving or shuttling to the patient. Other conventional pumps include, but are not limited to, diaphragm, rotary, vane, screw/turbine, or other types of conventional pumps. Some conventional drive mechanisms use a plunger to expel the liquid drug from the reservoir, which may result in a drive mechanism that generally has a length equal to a length of the reservoir. 
     The configurations of the various pump mechanisms may result in liquid drug doses to be nominally under- or over-delivered over time due to mechanical “sticking” or “slipping” of the pump mechanism. 
     Accordingly, there is a need for a simplified system for accurately expelling a liquid drug from a reservoir, which also reduces the overall size of a drug delivery device. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter. 
     In some approaches, a wearable drug delivery device that includes a reservoir and a delivery pump device is disclosed. The reservoir may be configured to store a liquid drug. The delivery pump device may be coupled to the reservoir for receiving the liquid drug from the reservoir. The delivery pump device may include a chamber body defining a pump chamber, an inlet port configured to enable a liquid drug from the reservoir to be drawn into the pump chamber, a sliding fluidic member including a flow orifice and a fluid pathway to a needle, a plunger including a plunger channel configured to be engaged with the sliding fluidic member, and a shape memory alloy wire coupled to the sliding fluidic member. The shape memory alloy wire is operable to draw the liquid drug from the reservoir through the inlet port and into the pump chamber by pulling the sliding fluidic member and the plunger in a first direction. The sliding fluidic member is configured to enable the liquid drug to be drawn into the pump chamber and expelled from the pump chamber into a fluid pathway to a needle for output. 
     In another aspect, a delivery pump device of a wearable drug delivery device is provided. The delivery pump device includes a chamber body, a plunger, a sliding fluidic member and a shape memory alloy. The chamber body defines a pump chamber and includes a hard stop and an inlet valve and operable to receive a liquid drug from a reservoir. The plunger may be movable within the pump chamber of the chamber body and configured with a plunger channel. The sliding fluidic member may be movable within the pump chamber and include a needle coupling, a flow orifice, a face seal and an anchor portion. The anchor portion is positioned and movable within the plunger channel in a leak-proof configuration. The shape memory alloy wire may be coupled to the anchor portion. The shape memory alloy wire is operable to pull the anchor portion and the plunger toward the hard stop. 
     In a further aspect, a method for controlling a delivery pump device to output a liquid drug is disclosed. The method includes determining a time to output a liquid drug from the delivery pump device. A control signal may be generated to actuate the delivery pump device. A control signal may be applied to a pump mechanism of the delivery pump device. The pump mechanism includes a shape memory alloy wire that is configured to respond to the applied control signal. As a pump chamber of the deliver pump device fills with the liquid drug, it is determined that the applied control signal is to be removed from the pump mechanism of the delivery pump device. The applied control signal may be removed from the pump mechanism to enable the liquid drug to be delivered from the pump chamber. Delivery of the liquid drug may be confirmed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, like reference characters generally refer to the same parts throughout the different views. In the following description, various examples of the present disclosure are described with reference to the following drawings, in which: 
         FIG. 1  illustrates a schematic diagram of a drug delivery system according to examples of the present disclosure. 
         FIG. 2  illustrates a side cross-sectional view of an intermediate pumping chamber of the delivery pump device in an initial state of a pumping cycle. 
         FIG. 3A  illustrates a side cross-sectional views of an intermediate pumping chamber of the delivery pump device in transition from an initial state of a pumping cycle for the intermediate pumping chamber shown in the example of  FIG. 2 . 
         FIG. 3B  illustrates an example fill area of an example pump chamber of an intermediate pumping chamber. 
         FIG. 4  illustrates a cross-sectional view of the example intermediate pumping chamber in a filled state prior to delivery of the liquid drug from the pump chamber. 
         FIG. 5  illustrates a cross-sectional view of the example intermediate pumping chamber transitioning from the filled state of the example of  FIG. 4  to delivery preparation state. 
         FIG. 6  illustrates a cross-sectional view of the example intermediate pumping chamber initiating delivery of the liquid drug from the pump chamber. 
         FIG. 7  illustrates a cross-sectional view of the example intermediate pumping chamber in a state in which movement of the plunger delivers the liquid drug from the pump chamber. 
         FIG. 8  illustrates a cross-sectional view of another example architecture of an intermediate pumping chamber. 
         FIG. 9  illustrates a side cross-sectional view of an intermediate pumping chamber of the delivery pump device in transition from an initial state of a pumping cycle for the intermediate pumping chamber shown in the example of  FIG. 8 . 
         FIG. 10  illustrates a side cross-sectional view of the intermediate pumping chamber in the example of  FIG. 9  in a filled state prior to delivery of the liquid drug from the pump chamber. 
         FIG. 11  illustrates a cross-sectional view of the example intermediate pumping chamber transitioning from the filled state of the example of  FIG. 4  to a delivery state by movement of the plunger which delivers the liquid drug from the pump chamber. 
         FIG. 12  illustrates an example configuration of electrical contacts for various control aspects of an example of a delivery pump device. 
         FIG. 13  is a flow chart of a process that may utilize the examples of  FIGS. 1-12  to expel a drug from a delivery pump device. 
     
    
    
     The drawings are not necessarily to scale. The drawings are merely representations, not intended to portray specific parameters of the disclosure. The drawings are intended to depict examples of the disclosure, and therefore are not be considered as limiting in scope. Furthermore, certain elements in some of the figures may be omitted, or illustrated not-to-scale, for illustrative clarity. Still furthermore, for clarity, some reference numbers may be omitted in certain drawings. 
     DETAILED DESCRIPTION 
     Systems, devices, and methods in accordance with the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, where one or more examples are shown. The systems, devices, and methods may be embodied in many different forms and are not to be construed as being limited to the examples set forth herein. Instead, these examples are provided so the disclosure will be thorough and complete, and will fully convey the scope of methods and devices to those skilled in the art. Each of the systems, devices, and methods disclosed herein provides one or more advantages over conventional systems, components, and methods. 
     The pump mechanism described herein is intended to have the above advantageous characteristics. In addition, the pump mechanism is configured to output a set amount of a liquid drug during each “pulse” of the pump, which assumes that the displacing members of the pump mechanism travel from their “start” limits to their “stop” limits. The travel of the pump mechanism may be called the “pump stroke” and may have a variable distance of travel. In some examples, the pump stroke may be adjustable or may be a preset distance. A “pulse” may be considered as an actuation of the pump in response to a control signal during which a dose of liquid drug is output from the reservoir of the wearable drug delivery device. 
       FIG. 1  illustrates a simplified block diagram of an example system  100 . The system  100  may be a wearable or on-body drug delivery device that is configured to be attached to the skin of a patient  103 . The system  100  may include a controller  102 , a pump mechanism  104  (also referred to as “pump  104 ”), and a sensor  108 . 
     The sensor  108  may be an analyte sensor operable to detect ketones, lactates, uric acid, alcohol, glucose and the like. For example, the sensor  108  may be a glucose monitor such as, for example, a continuous glucose monitor. The sensor  108  may, for example, be operable to measure blood glucose (BG) values of a user to generate a measured BG level signal  112 . The controller  102 , the pump  104 , and the sensor  108  may be communicatively coupled to one another via a wired or wireless communication path. For example, each of the controller  102 , the pump  104  and the sensor  108  may be equipped with a wireless radio frequency transceiver operable to communicate via one or more communication protocols, such as Bluetooth®, or the like. As will be described in greater detail herein, the system  100  may also include a delivery pump device (also referred to as “device”)  105 , which includes a housing  114  defining an intermediate pumping chamber  115 , an inlet port  116 , and an outlet port  117 . The system  100  may include additional components not shown or described for the sake of brevity. 
     In an example, the controller  102  may receive a desired BG level signal indicating a desired BG level or BG range for the patient  103 . The desired BG level signal may be received from, for example, a user interface (not shown) to the controller  102  or another device, or by an algorithm that automatically determines an ideal BG level for the patient  103 . The sensor  108  may be coupled to the patient  103  and operable to measure an approximate value of a BG level of the user. In response to the measured BG level or value, the sensor  108  may generate a signal indicating the measured BG value. As shown in the example, the controller  102  may also receive from the sensor  108  via a communication path, the measured BG level signal  112 . 
     Based on the desired BG level signal and the measured BG level signal  112 , the controller  102  may generate one or more control signals for directing operation of the pump  104 . For example, one control signal  119  from the controller  102  may cause one or more power elements  123  operably connected with the device  105  to turn on or activate. As will be described with reference to the examples of  FIGS. 2-13 , the power element  123  may activate an SMA wire (not shown in this example) within the intermediate pumping chamber  115 . In response, the SMA wire may change shape and/or length, which in turn may change a configuration of the intermediate pumping chamber  115 . 
     An amount of a liquid drug  125  (e.g., insulin) may be drawn into the intermediate pumping chamber  115 , through the inlet port  116 , in response to a change in pressure due to the change in configuration of the intermediate pumping chamber  115 . For example, the amount of the liquid drug  125  may be determined based on a difference between the desired BG level signal and the actual BG signal level  112 . The amount of the liquid drug  125  may be determined as an appropriate amount of insulin to drive the measured BG level of the user to the desired BG level. Based on operation of the pump  104 , as determined by the control signal  119 , the patient  103  may receive the liquid drug from a reservoir  126  through a sequence of pulses. The system  100  may operate as a closed-loop system, an open-loop system, or as a hybrid system. 
     As further shown, the system  100  may include a needle deployment component  128  in communication with the controller  102 . The needle deployment component  128  may include a needle/cannula  129  deployable into the patient  103 . The cannula  129  may form a portion of a fluid path coupling the patient  103  to the reservoir  126 . 
     As further shown, the outlet port  117  may be coupled to the cannula  129 . The intermediate pumping chamber  115  via the outlet port  117  couple to a needle/cannula coupling (shown in another figure) that enables fluid from the reservoir  126  to be transferred to the cannula  129 . The cannula  129  may be configured to allow fluid expelled from the device  105  to be provided to the patient  103 . 
     The controller  102  may be implemented in hardware, software, or any combination thereof. The controller  102  may, for example, be a processor, a logic circuit or a microcontroller coupled to a memory  106 . The memory  106  may include logic  106 - 1  and settings  106 - 2 . The controller  102  may maintain a date and time and perform various functions (e.g., calculations or the like) that are usable to determine a status or state of various components of the system. The controller  102  may be operable to execute an algorithm such as an artificial pancreas (AP) algorithm stored in memory  106  as logic  106 - 1  that may be operable to enable the controller  102  to direct operation of the pump  104 . The logic  106 - 1  may enable operation of the delivery device  105 . For example, the controller  102  may be operable to receive an input from the sensor  108 , wherein the input corresponds to an automated drug delivery, such as an automated insulin delivery (AID), application setting that the controller  102  may utilize in the control of the intermediate pumping chamber  115 . Based on the AID application setting, the controller  102  may modify the behavior of the pump  104  and resulting amount of the liquid drug  125  to be delivered to the patient  103  via the device  105 . 
     In some examples, the sensor  108  may be, for example, a continuous glucose monitor (CGM). The sensor  108  may be physically separate from the pump  104  or may be an integrated component within a same or an adjacent housing thereof. The sensor  108  may provide the controller  102  with data indicative of measured or detected blood glucose levels of the user. 
     The power element  123  may be a battery, a piezoelectric device, or the like, for supplying electrical power to the device  105 . In other examples, the power element  123 , or an additional power source (not shown), may also supply power to other components of the pump  104 , such as the controller  102 , the memory  106 , the sensor  108 , and/or the needle deployment component  128 . 
     In an example, the sensor  108  may be a device communicatively coupled to the controller  102  and may be operable to measure a blood glucose value at a predetermined time interval, such as approximately every 5 minutes, 10 minutes, or the like. The sensor  108  may provide a number of blood glucose measurement values to an AP application executed by the controller  102  or by an external control device. 
     In some examples, the pump  104 , when operating in a normal mode of operation, provides insulin stored in the reservoir  126  to the patient  103  based on information (e.g., blood glucose measurement values, target blood glucose values, insulin on board, prior insulin deliveries, time of day, day of the week, inputs from an inertial measurement unit, global positioning system-enabled devices, Wi-Fi-enabled devices, or the like) provided by the sensor  108  or other functional elements of the pump  104 . For example, the pump  104  may contain analog and/or digital circuitry that may be implemented as the controller  102  for controlling the delivery of the drug or therapeutic agent. The circuitry used to implement the controller  102  may include discrete, specialized logic and/or components, an application-specific integrated circuit, a microcontroller or processor that executes software instructions, firmware, programming instructions or programming code enabling, for example, an AP application stored in memory  106 , or any combination thereof. For example, the controller  102  may execute a control algorithm and other programming code, such as the AP application, that may make the controller  102  operable to cause the pump  104  to deliver doses of the drug or therapeutic agent to a user at predetermined intervals or as needed to bring blood glucose measurement values to a target blood glucose value or range. The size and/or timing of the doses may be pre-programmed, for example, into the AP application by the patient  103  or by a third party (such as a health care provider, a parent or guardian, a manufacturer of the wearable drug delivery device, or the like) using a wired or wireless link. The AP application may also be operable to automatically adjust any settings that may be pre-programmed (such as dosage limits for insulin, a number of strokes or pulses to deliver, and the like) based on data received from sensor  108  or detectors (shown in another figure) within the intermediate pumping chamber  115 . The controller  102  may be coupled to the intermediate pumping chamber  115  via a communication path  188 . The controller  102  may deliver control signals to components (shown in other examples) of the intermediate pumping chamber  115 . 
     Although not shown, in some examples, the sensor  108  may include a processor, memory, a sensing or measuring device, and a communication device (not shown in this example). The memory may store an instance of an AP application as well as other programming code and be operable to store data related to the AP application. 
     In various examples, the sensing/measuring device of the sensor  108  may include one or more sensing elements, such as a blood glucose measurement element, a heart rate monitor, a blood oxygen sensor element, or the like. In an example, the sensor processor may include discrete, specialized logic and/or components, an application-specific integrated circuit, a microcontroller or processor that executes software instructions, firmware, programming instructions stored in memory, or any combination thereof. 
       FIG. 2  illustrates a side cross sectional view of the intermediate pumping chamber of the wearable drug delivery system example of  FIG. 1  in an initial position. The intermediate pumping chamber  200  may have a front  200   a  and a back  200   b  and be coupled to a reservoir containing a liquid drug via reservoir coupling  201 . The intermediate pumping chamber  200  may be operable to change configurations over the course of operation. For example, the initial position of  FIG. 2  may be a position in which a liquid drug from the reservoir has not been pulled into the pump chamber (shown in more detail in another figure). Components of the example intermediate pumping chamber  200  may include sliding fluidic member  1 , chamber body  10 , and plunger  3 . Additional components may include a valve  2 , such as a passive check valve, a plunger spring  4 , a fluidic member (FM) spring  5 , a shape memory alloy (SMA) wire  6 , a hard stop  7 , and a face seal  11 . The inlet port  116  of  FIG. 1  may be formed by the passive check valve  2  and be configured to enable a liquid drug from the reservoir to be drawn into a pump chamber (shown in more detail in another figure). The plunger spring  4  and the FM spring  5  may be compression springs. The FM spring  5  and the plunger spring  4  are shown (in  FIG. 2 ) in their rest position when the intermediate pumping chamber  200  is this initial position. Of course, other types of springs or other types of devices may be used in place of springs in the example intermediate pumping chamber  200 . 
     In the example, the position of the sliding fluidic member  1  as shown in  FIG. 2  may be considered a rest position or an initial position. The sliding fluidic member  1  may be configured with an anchor portion  1   a,  a needle/cannula coupling  1   b,  and a flow orifice  12 . The needle/cannula coupling  1   b  may be configured, for example, as a hollow member, to provide a fluid pathway  16  to a needle/cannula (not shown in this example). The sliding fluidic member  1  may include a flow orifice  12  that is built into the sliding fluidic member  1  between the anchor portion  1   a  and the needle/cannula coupling  1   b.  For example, the sliding fluidic member  12  may include the flow orifice  12  and the fluid pathway  16  to a needle. The sliding fluidic member  1  may be coupled to the needle or cannula, such as  129  of  FIG. 1 . The anchor portion  1   a  may include structures (not shown for ease of illustration in this example) that connect the anchor portion  1   a  to the needle/cannula coupling  1   b.  The needle/cannula coupling  1   b  may be configured to remain coupled to the needle/cannula (not shown in this example) and extend into the chamber body  10 . For example, the needle/cannula coupling  1   b  may be an elastic member, a multi-sectional, leak-proof, extendable tube, a combination thereof, or the like. The flow orifice  12  may be surrounded by structures that couple the needle/cannula coupling  1   b  to the anchor portion  1   a  but allow the liquid drug when in the pump chamber to enter the flow orifice  12  and flow in the fluid pathway  16  to the needle/cannula (shown in  FIG. 1 ). 
     In the example intermediate pumping chamber  200 , the passive check valve  2  may be configured to prevent back-flow of the liquid drug when the pump chamber is filled with liquid drug (shown in a later example/figure) from the reservoir (shown in  FIG. 1 ). 
     The plunger  3  may be configured to form a leakproof seal against the side of the chamber body  10 . The plunger  3  as shown in later examples is operable to draw liquid drug from the reservoir and deliver the liquid drug through the fluid pathway  16  to the needle or cannula (not shown in this example). A surface of the plunger  3  facing the rear  200   b  of the intermediate pumping chamber  200  may be coupled to or sit against a plunger spring  4 . The plunger spring  4  may, for example, be a compression spring that is shown at rest in  FIG. 2 . The end of the plunger spring  4  opposite the plunger  3  may couple to or rest against the hard stop  7 . 
     In this example, the plunger  3  is configured with a plunger channel  3   a  and plunger flexure snap  9 . The plunger channel  3   a  may be a hollow center portion in which fits an anchor portion  1   a  of the sliding fluidic member  1 . The plunger channel  3   a  may be configured to surround the anchor portion  1   a  of the sliding fluidic member  1 . The interface between the plunger channel  3   a  and the anchor portion  1   a  is leakproof, but the anchor portion  1   a  is configured to slide back and forth through the plunger channel  3   a.  The plunger flexure snaps  9  are flexible and may extend along a surface of the anchor portion  1   a  of the sliding fluidic member  1  and terminate with a bulbous portion (or in another embodiment, a concavity, or a portion complementary to the hard stop flexure snaps  8 ). 
     A face seal  11  may be disposed between the anchor portion  1   a  and the needle/cannula coupling  1   b  of the sliding fluidic member  1  and at a perimeter of the flow orifice  12 . The face seal  11  may be operable to provide a leakproof seal of the flow orifice  12  that limits leakage of any liquid drug through or around a flow orifice  12  and into the fluid pathway  16  to the needle or cannula. The face seal  11  may be configured to prevent flow of the liquid drug to the patient while the intermediate pumping chamber is in the initial position. In some stages of operation, the face seal  11  may, for example, be under pressure from the plunger spring  4  of the intermediate pumping chamber  200  that prevents any liquid drug from entering the fluid pathway  16 . 
     The SMA wire  6  may be nitinol or other known shape memory alloy wire that is operable to change length or shape in response to application of an electric current. For example, the SMA wire  6  may be coupled to a power source via circuitry that, when actuated in response to a control signal from a controller (such as shown in  FIG. 1 ), is configured to apply a current or voltage to actuate the SMA wire  6 . 
     The hard stop  7  may be configured to limit movement of the plunger  3 . The hard stop  7  may be configured to include two hard stop flexures  8   a  that are configured to extend from the hard stop  7  toward the front  200   a  of the intermediate pumping chamber  200 . In the example intermediate pumping chamber  200 , each of the two hard stop flexures  8   a  may include hard stop flexure snap  8  at the end of the hard stop flexure  8   a  closest to the plunger  3 . The hard stop flexure snaps  8  are, in this example, two flexible arm-like structures with inward facing concavities (or in another embodiment, protrusions, or a portion complementary to the plunger flexure snaps  9 ) at the respective ends of the flexible arm-like structures. While two hard stop flexure snaps  8  are shown, the number of hard stop flexure snaps  8  may be more or less, such as 1, 3, or 4, and may be utilized in other examples to engage more or less of the plunger flexure snaps  9  of the plunger  3 . Interaction of the hard stop flexure snaps  8  and the plunger flexure snaps  9  are described in more detail with later examples. 
       FIG. 3A  illustrates a side cross-sectional view of the intermediate pumping chamber in transition from an initial position to a filled stage. 
     In  FIG. 3A , the operation of the intermediate pumping chamber  200  is shown in response to the filling with liquid drug  20  from the reservoir via reservoir coupling  201 . The SMA wire  6  is coupled to the anchor portion  1   a  and to circuitry (not shown in this example) responsive to signals from a controller (shown in an earlier example). 
     In response to being actuated, the SMA wire  6  may be pull on the anchor portion  1   a  of the sliding fluidic member  1  which pulls on the plunger  3  in the direction shown by the Arrow A. The pulling of the SMA wire  6  in the direction of Arrow A results in the sliding fluidic member  1  and the plunger  3  being pulled away from the front surface  205  of the intermediate pumping chamber  200  and away from the passive check valve  2 . The pulling action of the SMA wire  6  on the anchor portion  1   a  creates a vacuum within the pump chamber  22 . The vacuum causes the passive check valve  2  to open in the same direction as the sliding fluidic member  1  and plunger  3  are moving (as indicated by the unlabeled arrow on the passive check valve  2 ) and allows the pump chamber  22  to begin filling with liquid drug  20  from the reservoir via the reservoir coupling  201 . 
     During this filling stage, the face seal  11  is asserted at a higher force (against a first plunger surface  3   c  of the plunger  3 ) on the flow orifice  12  due to compression of fluidic member spring  5  (e.g., F=−kx, where F is force, k is the spring constant and x is the distance the spring is compressed from its rest position). The position of hard stop  7  opposite from the front surface  205  of the intermediate pumping chamber  200  may be varied under tightly controlled conditions that permit adjustment of the pump stroke, or, alternatively, the position of the hard stop  7  may be factory configured for a preset pump stroke. The length of SMA wire  6  may configured based on the adjustment or setting of the pump stroke of the plunger and the position of the hard stop  7  to achieve the correct amount of pump stroke. 
     In the example of  FIG. 3A , the plunger  3  and sliding fluidic member  1  are translating backwards toward the rear  200   b  of the intermediate pumping chamber  200 . As the plunger  3  and the sliding fluidic members  1  are translating backwards, the hard stop flexures  8   a  and will interact. The plunger flexure snaps  9  are configured with semi-circular protrusions that when contacted by the hard stop flexure  8   a  cause the hard stop flexure  8   a  on both sides of the hard stop  7  to open toward the respective sides of the chamber body  10 . As the hard stop flexure  8   a  separates the semicircular protrusions on the plunger flexure snaps  9  fill the hard stop flexure snaps  8 , which are dimples in the hard stop flexure  8   a  of hard stop  7 . This results in a two-way latch/snap that prevents the sliding fluidic member  1  and plunger  3  from translating further backwards toward the rear  200   b  of the intermediate pumping chamber  200 . 
       FIG. 3B  illustrates an example of the active flow area of pump chamber in the example of  FIG. 3A . As it is shown in the example of  FIG. 3B , the active flow area  33  may be an annulus. An annular active flow area  33  enables larger components, such as a plunger  3 , slidable fluidic member  1 , and intermediate pumping chamber  10  to be used, which is favorable to component manufacturing and assembly. For example, the annular active flow  33  may be the result of using cylindrical structures (such a cylindrical plunger and cylindrical chamber body  10  (shown in an earlier example) and the like) that are easier to manufacture and assemble. Of course, other shapes such as ovular, rectangular, square, or the like may be used. For example, a ratio between d 1  and d 2  can be established such that dimensional control on the active flow area  33  section is achieved. This dimensional control facilitates increasing the scale of the size of the pump chamber and plunger size such that the manufacturing tolerance may be a small, or smaller, percentage of the actual size of the device  105 . By controlling those dimensions d 1  and d 2 , a desired pump chamber volume may be achieved. Given the small pump volumes, the larger the chamber and plunger become, the closer the chamber and plunger will become in nominal dimension. The approximate area of the active flow area  33  may be determined using the following the equation: [(d 2 /2)2×π]−[(d 1 /2)2×π]−(area of flow orifice  12  that extends beyond d 1 ), where d 2  is the diameter of the plunger  3  and d 1  is the diameter of the sliding fluidic member  1 . 
     In  FIG. 4 , the intermediate pumping chamber  200  has reached full stroke, the pump chamber  22  is full of liquid drug  20  and due to the pressure essentially returning to approximately 0 pounds per square inch gauge (psig), the passive check valve  22  has closed. Both plunger spring  4  and FM spring  5  are compressed and storing energy. In this example, the plunger flexure snaps  9  are operable to accomplish several actions, such as limiting travel of the plunger  3  within the intermediate pumping chamber  200  when drawing the liquid drug  20  from the reservoir (i.e.,  126  of  FIG. 1 ) into the pump chamber  22 , assist the SMA wire  6  in maintaining the stored energy of the plunger spring  4  and the FM spring  5 , preventing the plunger  3  from transitioning back toward the front surface  205  until the sliding fluidic member  1  has reached a specific point in its stroke, and the like. As explained further with reference to another figure, the plunger flexure snaps  9  and the hard stop flexure snaps  8  may provide electrical interfaces (e.g., electrical contacts or the like on each surface thereof) that when coupled to control circuitry are operable to confirm the pump chamber  22  is full or that delivery of the liquid drug has started. The position shown in  FIG. 4  may be referred to as the full or loaded position. 
     In  FIG. 5 , in response to current being released from the SMA wire  6 , the SMA wire  6  is not energized and begins to return to its pre-actuation state. In addition, the FM spring  5  pushes (as shown by the arrow B) the sliding fluidic member  1  back toward the initial position shown in  FIG. 2 . Depending upon the configuration of the SMA wire  6  and the FM spring  5 , the SMA wire  6  may serve as a brake on (and limit the force applied by) the FM spring  5  to slow the movement of the sliding fluidic member  1  in the direction of arrow B. Alternatively, the SMA wire  6  may be configured to allow the FM spring  5  to assert its full force on the sliding fluidic member  1 . 
     As the sliding fluidic member  1  moves toward the front surface  205 , the flow orifice  12  becomes exposed as the face seal  11  is no longer intact with the front surface of the plunger  3 . In this example, the sliding fluidic member  1  can move within the space of the pump chamber  22  without displacing much, if any, liquid drug into the fluid pathway  16 . 
     In addition, as the sliding fluidic member  1  moves toward the front surface  205 , the plunger  3  remains stationary as the plunger flexure snaps  9  and hard stop flexure snaps  8  remain coupled due to support provided by the sliding fluidic member  1 . 
     In the examples, when fully retracted into the plunger  3  (as shown in  FIG. 3A ) the anchor portion  1   a  of the sliding fluidic member  1  supports the plunger flexure snaps  9 . The support provided by the sliding fluidic member  1  to the plunger flexure snaps  9  serves to keep the plunger flexure snaps  9  coupled with the hard stop flexure snaps  8 . 
     However, as the sliding fluidic member  1  moves in the direction of arrow B in  FIG. 5 , the coupling between the plunger flexure snaps  9  and hard stop flexure snaps  8  becomes unstable. 
       FIG. 6  illustrates the relaxing of the SMA wire  6  and the sliding fluidic member  1  is shown as having reached the forward limit of its travel due to hitting the inside of the front of the intermediate pumping chamber  200  in response to the force of the FM spring  5  against the anchor portion  1   a.    
     Due to lack of support provided by the anchor portion  1   a  to the plunger flexures  9   a,  the plunger flexures  9   a  may be more prone to bending. As a result of the lack of support the hard stop flexures  8   a  do not need to bend as much to uncouple the respective plunger flexure snaps  9  and hard stop flexure snaps  8 . The travel of the respective hard stop flexure snaps  8  and plunger flexure snaps  9  are shown by arrow E and arrow F. As shown in  FIG. 6 , the force asserted by plunger spring  4  on the plunger  3  causes the plunger  3  to move in the direction indicated by arrow C creating instability at the coupling of the respective plunger flexure snaps  9  and the hard stop flexure snaps  8 . The instability allows the force of the plunger spring  4  to overcome the frictional forces that keep the plunger flexure snaps  9  and hard stop flexure snaps  8  coupled, the respective plunger flexures  9   a  and hard stop flexures  8   a  bend and thus release the plunger  3  for continued travel toward the front of the intermediate pumping chamber  200 . 
     In a further example, the uncoupling of the plunger flexure snaps  9  and hard stop flexure snaps  8  also breaks the electrical connection formed by the coupled plunger flexure snaps  9  and hard stop flexure snaps  8 , which a controller may interpret as delivery of the liquid drug to the fluid pathway  16  and to the user. 
       FIG. 7  illustrates movement of the plunger to deliver the liquid drug from the pump chamber  22 . In the example of  FIG. 7 , the plunger  3  is shown collapsing the pump chamber  22  under the force of the plunger spring  4  and expelling the liquid drug  20  of the pump chamber  22  out the exit orifice  12 . The passive check valve  2  is closed under the pressure of the liquid drug  20  and keeps any liquid drug  20  from returning to the reservoir. The pump flow rate Q, is a factor of spring rate and flow orifice diameter/length and pipe dimensions to the patient, best described by Poiseuille&#39;s law, as follows: 
     
       
         
           
               
               
               
             
               
                   
                   
               
             
            
               
                   
                 Q 
                 Flow rate 
               
               
                   
                 P 
                 Pressure 
               
               
                   
                 r 
                 Radius 
               
               
                   
                 η 
                 Fluid viscosity 
               
               
                   
                 l 
                 Length of tubing 
               
               
                   
                   
               
               
                   
                 
                   
                     
                       
                         Q 
                         = 
                         
                           
                             π 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             
                               Pr 
                               4 
                             
                           
                           
                             8 
                             ⁢ 
                             η 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             l 
                           
                         
                       
                     
                   
                 
               
            
           
         
       
     
     When the pump chamber  22  is fully collapsed under the force of the plunger spring  4 , the intermediate pumping chamber  200  is returned to its initial position as shown in  FIG. 2  with the intermediate pumping chamber  200  at rest and ready to be re-energized for another pulse to deliver the liquid drug to a user. 
     In contrast to the embodiment shown in  FIGS. 2-7 , the plunger flexure snaps  9  and hard stop flexures  8   a  and hard stop flexure snaps  8  may be optional as other means of limiting travel of the plunger  3  are available. For example, in  FIG. 8 , the intermediate pumping chamber may limit itself hydraulically. In addition, in some configurations or applications (e.g., pumping applications that last longer than a use cycle of a drug delivery device for insulin) the use of flexure snaps may induce higher frictional losses, which may be intolerable for a long duration (e.g., greater than 1 week) of use. 
       FIG. 8  illustrates a side cross sectional view of another example of intermediate pumping chamber of a wearable drug delivery system. The intermediate pumping chamber  800  may have a front  800   a  and a back  800   b  and be coupled to a reservoir containing a liquid drug via reservoir coupling  801 . The intermediate pumping chamber  800  may be operable to change configurations over the course of operation. For example, the initial position of  FIG. 8  may be a position in which a liquid drug from the reservoir has not been pulled into the pump chamber (shown in more detail in a later figure). The main components of the example intermediate pumping chamber  200  may include sliding fluidic member  815 , chamber body  880 , and plunger  820 . Additional components may include a passive check valve  810 , a plunger spring  830 , a fluidic member (FM) spring  840 , a shape memory alloy (SMA) wire  850 , a hard stop  870  and a face seal  811 . The plunger spring  830  and the FM spring  840  may, for example, be compression springs and are shown in their rest position when the intermediate pumping chamber  800  is in this initial position. The initial position of the plunger  820  and the sliding fluid member  815  shown in the example of  FIG. 8  may also be referred to as the parked position at the front  800   a  of the intermediate pumping chamber  800 . Of course, other types of springs or other types of devices may be used in place of springs in the example intermediate pumping chamber  800 . 
     The sliding fluidic member  815  may be configured with an anchor portion  815   a,  a needle/cannula coupling  815   b,  and a flow orifice  812 . The sliding fluidic member  815  may include a flow orifice  812  that is built into the sliding fluidic member  815 . The sliding fluidic member  1  may be coupled to the needle or cannula, such as  129  of  FIG. 1 . The anchor portion  815   a  may include structures (not shown for ease of illustration in this example) that connect to the needle/cannula coupling  815   b.  The structures are configured to provide fluid passages in the flow orifice  812  that allow the liquid drug to enter the flow orifice and flow in the fluid pathway  816  to the needle/cannula. 
     In the example intermediate pumping chamber  800 , the passive check valve  810  may be configured to prevent back-flow of the liquid drug when the pump chamber is filled with liquid drug (shown in a later example) from the reservoir (shown in  FIG. 1 ). 
     The plunger  820  may be configured to form a leakproof seal against the side of the chamber body  880 . The plunger  820  as shown in later examples is operable to draw liquid drug from the reservoir and deliver the liquid drug through the fluid pathway  816  to the needle or cannula (not shown in this example). A surface of the plunger  820  facing the rear  800   b  of the intermediate pumping chamber  800  may be coupled to, or sit against, a plunger spring  830 . The end of the plunger spring  830  opposite the plunger  820  may couple to, or rest against, the hard stop  870 . 
     In this example, the plunger  820  is configured with a plunger channel  820   a  and plunger hard stop  860 . The plunger channel  820   a  may be a hollow center portion in which fits an anchor portion  815   a  of the sliding fluidic member  815 . The plunger channel  820   a  may be configured to surround the anchor portion  815   a  of the sliding fluidic member  815 . The interface between the plunger channel  3   a  and the anchor portion la is leakproof, but the anchor portion  1   a  is configured to slide back and forth through the plunger channel  820   a.    
     A face seal  811  may be disposed between the plunger  820  and the needle/cannula coupling  815   b  of the sliding fluidic member  815  to provide a leakproof seal. The face seal  811  may be formed as a compression seal between the sliding fluidic member  815  and a surface of the plunger  820 . Alternatively, or in addition, the face seal  811  may be an elastomeric seal coupled to the sliding fluidic member  815  (or the plunger  820 ). The face seal  811  may be configured to limit leakage of any liquid drug through or around a flow orifice  812  and into the fluid pathway  16  to the needle or cannula. The face seal  811  may be further configured to prevent flow of the liquid drug to the patient while the intermediate pumping chamber is in the initial position. In some stages of operation, the face seal  811  may, for example, be under pressure from the plunger spring  830  of the intermediate pumping chamber  800  that prevents any liquid drug from entering the fluid pathway  816 . 
     The SMA wire  850  may be nitinol or other known shape memory alloy wire that is operable to change length or shape in response to application of a current. For example, the SMA wire  850  may be coupled to a power source via circuitry that, when actuated in response to a control signal from a controller (such as shown in  FIG. 1 ), is configured to apply a current or voltage to actuate the SMA wire  850 . The hard stop  870  may be configured to limit movement of the plunger  830  when the hard stop  870  is contacted by the plunger hard stop  860 . 
       FIG. 9  illustrates a side cross-sectional view of an intermediate pumping chamber of the delivery pump device in transition from an initial state of a pumping cycle for the intermediate pumping chamber shown in the example of  FIG. 8 . In the example of  FIG. 9 , the SMA wire  850  may be energized (or actuated) by a controller. In response to being energized or actuated, the SMA wire  850  may begin pulling (toward the back  800   b  in the direction shown by arrow G) the anchor portion  815   a  of the sliding fluidic member  815  toward the back  800   b  of the intermediate pumping chamber  800 . 
     As the anchor portion  815   a  is pulled toward the back  800   b,  the plunger spring  830  and the FM spring  840  are compressed from their resting positions. In addition, a vacuum is created that draws liquid drug  825  from the reservoir via the reservoir coupling  801  into pump chamber  822 . The face seal  811  maintains pressure against the plunger  820  as the anchor portion  815   a  is pulled toward the back  800   b  by SMA wire  850 , thereby preventing the liquid drug from entering the flow orifice  812 . 
       FIG. 10  illustrates a side cross-sectional view of the intermediate pumping chamber in the example of  FIG. 9  in a filled state prior to delivery of the liquid drug from the pump chamber. In the example of  FIG. 10 , the controller (not shown in this example) no longer causes a current to be applied to the SMA wire  850 . 
     When current is removed from the SMA wire  850 , a force imparted by the FM spring  840  may begin to cause reverse motion of the anchor portion  815   a  of the sliding fluidic member  815 . The anchor portion  815   a  may begin traveling within the plunger  820  and through the plunger channel  820   a  while the plunger  820  is momentarily hydraulically stalled in position (by the incompressible volume of the liquid drug  825 ) against the hard stop  860  due to the plunger&#39;s greater surface area vis a vis a portion of the surface area of the sliding fluidic member opposite the face seal  811 . 
     In the example of FIG. 10 , the SMA wire  850  may be energized by a controller, for example, until a current spike is detected by the controller when the plunger hard stop  860  hits the wall formed by hard stop  870 . The timing of the release of the plunger  820 , in the example, may be regulated by hydraulic damping due to the liquid drug  825  in the filled pump chamber  822  and the pull exerted on the anchor portion  815   a  by the energized SMA wire  850 . 
     Since the sliding fluidic member  815  is not displacing fluid during movement toward the front  800   a,  there may be no additional force preventing the sliding fluidic member  815  from achieving a “parked position” before the plunger  820  begins to move toward the front  800   a.  Upon movement of the plunger  820 , all the liquid drug  825  may be expelled from the pumping chamber  822 . 
       FIG. 11  illustrates a cross-sectional view of the example intermediate pumping chamber transitioning from the filled state of the example of  FIG. 4  to a delivery state. 
     Based on a spring rate of the FM spring  840 , surface area of the plunger contacting the fluid, viscosity of fluid and flow orifice  12  parameters, fluid pathway  816  parameters, and the like, the plunger  820 , in the example of  FIG. 11 , may begin traveling toward the parked position at the front  800   a  before the sliding fluidic member  815  reaches the parked position against the front  800   a  of the intermediate pumping chamber  800 . In  FIG. 11 , the sliding fluidic member  815  is shown in the parked position against the front  800   a  of the intermediate pumping chamber  800 . The plunger spring  830  applies force to the plunger  820  that causes the plunger  820  to move toward the front  800   a.  As the plunger  820  is moving and the flow orifice  812  is no longer sealed by the face seal  811 , the liquid drug  825  is expelled from the pump chamber  822  by the movement of the plunger  820  toward the front  800   a  of the of the intermediate pumping chamber  800 . 
     When the plunger spring  4  returns to its initial position or parked position as shown in the  FIG. 8 , the intermediate pumping chamber  800  may be ready and waiting for another pulse. 
       FIG. 12  illustrates an example configuration of electrical contacts for various control aspects of the delivery pump device. 
     The example configuration  1200  shows examples of a plunger flexure  1230 , a hard stop flexure  1240  and a controller  1210 . 
     The plunger flexure  1230  may include the plunger flexure snap  1233 . The plunger flexure snap  1233  may be a protrusion disposed at the end of the plunger flexure  1230  as shown in earlier embodiment of  FIGS. 2-7 . The plunger flexure snap  1233  may include plunger flexure snap (PFS) contacts  1237   a  and  1237   b  that are coupled together by a wire  121 . 
     The hard stop flexure  1240  may include a hard stop snap  1243 . Disposed within the hard stop flexure snap  1243  are hard stop snap (HSS) contacts  1247   a  and  1247   b.  The hard stop flexure snap  1243  may be a dimple, or bowl-shaped indent, in the hard stop flexure  1240  as shown in the earlier embodiment of  FIGS. 2-7 . The HSS contacts  1247   a  and  1247   b  are shown coupled via wired connections to a controller  1210  of a drug delivery device, such as  104  in the example of  FIG. 1 . The plunger flexure snap  1233  is configured to interact with the hard stop snap  1243 . Of course, the plunger flexure snap  1233  and the hard stop snap  1243  may have other shapes that enable coupling of the respective snaps  1233  and  1243 . 
     The controller  1210  may be coupled to HSS contact  1247   a  via connector  1203  and to HSS contact  1247   b  by connector  1207 . The controller  1210  may be operable to respond when plunger flexure snap  1233  moves in the direction of arrow M and PSF contacts  1237   a  and  1237   b  contact HSS contacts  1247   a  and  1247   b,  respectively. Upon making contact, a circuit is completed in the controller  1210 , which indicates that the plunger has reached the hard stop of the intermediate pumping chamber (shown in earlier examples). In the example of  1200 , electrical contacts are shown as examples; however, other devices and mechanisms may be used to determine a status of the drug delivery device, such as  105  of  FIG. 1 , such as additional electrical switches and interconnects, optical devices coupled to the controller and configured to indicate positions of the plunger, magnetic/eddy current detectors, capacitive and fluid detection devices coupled to various components within a pump chamber, a linear variable displacement transducer (LVDT) or other linear displacement measuring tool, a pressure sensor, a flow sensor on an inlet or a Bourdon tube. The Bourdon tube, for example, may be configured to detect pressure causing strain or deformation in tubing, such as the fluid pathway  16  or  816 . The flow sensor, for example, may be operable to respond to check valve leakage or backflow. 
     In another example, a controller, such as  102  of  FIG. 1 or 1210  of  FIG. 12 , may be configured to execute logic that causes the controller to perform different functions.  FIG. 13  is a flow chart of a process that may utilize the examples of  FIGS. 1-12  to expel a drug from a delivery pump device. 
     In the process  1300 , for example, the controller may determine that it is time to output a drug from the delivery pump device. For example, the controller may be equipped with a clock or an input device that indicates to the controller that a dose of medication is supposed to be delivered to a user ( 1310 ). 
     In response to the determination, the controller may generate a control signal to actuate delivery pump device ( 1320 ). The controller may be operable to output the control signal, for example, to a pump mechanism that is operable to move the sliding fluidic member as described with reference to the examples of  FIGS. 2-11 . 
     In the example, the controller may be operable to apply the control signal to the pump mechanism ( 1330 ). The pump mechanism may be a shape memory alloy wire (as described with reference to earlier examples) or an electric motor. In some examples, the intermediate pumping chamber and associated mechanisms may include a drive system coupled to the sliding fluidic member (shown in the examples of  FIGS. 2-11 ). The drive system may, for example, be configured to be moved by a rotary cam, a linkage, a rack, or a leadscrew with an escapement mechanism. In another specific example, the drive system may be geared to allow use of low power electric motors. 
     As the control signal is being applied to the pump mechanism, the pump chamber (shown in earlier examples) is being filled with a liquid drug. As described with reference to the earlier examples, a shape memory wire is used to pull the sliding fluidic member to enable filling of the pump chamber. 
     The controller may, for example, be configured to determine that the control signal is to be removed from the pump mechanism of the delivery pump device ( 1340 ). The determination may be made as described with reference to the example configuration shown in  FIG. 12 . As an alternative example, the sliding fluidic member may be magnetically energized, and an eddy current can be measured and evaluated to determine a proximity of the sliding fluidic member to the hard stop wall. The eddy current configuration may allow partial dosing or multi-dosing within the same intermediate pumping chamber as the eddy current may have different values as the sliding fluidic member travels. Of course, other methods or placements of electrical contacts may be used to determine the position of the sliding fluidic member within the intermediate pumping chamber. Upon determining that the control signal may be removed from the pump mechanism, the controller may, at  1350 , stop applying or having applied a signal (responsive to the control signal) the drive mechanism, such as the shape memory alloy. By stopping the application of the control signal, the controller enables the springs of the intermediate pumping chamber to begin expelling the liquid drug from the pump chamber and to the patient via the fluid pathway to the needle/cannula. For example, the expelling of the liquid drug may enable delivery of the liquid drug from the drug delivery device. 
     In an operational example, the delivery of the liquid drug to a needle or cannula in response to removing the control signal from the pump mechanism may include additional steps. For example, in response to the shape memory alloy stopping pulling of the sliding fluidic member, the fluidic member spring may begin decompressing. The decompressing fluidic member spring may cause the sliding fluidic member to travel toward the front of the chamber body, while the plunger remains stationary due to being hydraulically blocked by the liquid drug in the pump chamber. The liquid drug is incompressible which counteracts the force exerted by the plunger spring until such time as the sliding fluidic member reaches a rest position or initial position as shown in the example of  FIG. 2 . In the example, the flow orifice is available to enable the liquid drug to flow into the needle coupling upon the sliding fluidic member reaching the initial position. With the sliding fluidic member is at the initial position or rest position, the plunger spring begins to decompress causing liquid drug to be expelled from the pump chamber into the needle coupling. 
     The controller may be operable, at  1360 , to confirm that the liquid drug was delivered or expelled, or has begun to be delivered or expelled, from the pumping chamber. For example, the sliding fluidic member may include electrical contacts or the like, such as the earlier eddy current example. 
     The whole system can be moved by sealing the back side of the plunger/sliding fluidic member and drawing a vacuum using a small air pump. The system would allow pressure to be measured in the vacuum chamber and through a calculation using Boyles Law (P 1 V 1 =P 2 V 2 ), the position of the plunger can be established. 
     The system may be modified to utilize phase changing wax in the movement of the plunger in place of the shape memory alloy as described in U.S. Pat. No. 10,391,237, the disclosure of which is incorporated by reference in its entirety herein. 
     Software related implementations of the techniques described herein may include, but are not limited to, firmware, application specific software, or any other type of computer readable instructions that may be executed by one or more processors. Hardware related implementations of the techniques described herein may include, but are not limited to, integrated circuits (ICs), application specific ICs (ASICs), field programmable arrays (FPGAs), and/or programmable logic devices (PLDs). In some examples, the techniques described herein, and/or any system or constituent component described herein may be implemented with a processor executing computer readable instructions stored on one or more memory components. 
     In addition, or alternatively, while the examples may have been described with reference to a closed loop algorithmic implementation, variations of the disclosed examples may be implemented to enable open loop use. The open loop implementations allow for use of different modalities of delivery of insulin such as smart pen, syringe or the like. For example, the disclosed AP application and algorithms may be operable to perform various functions related to open loop operations, such as the generation of prompts requesting the input of information such as weight or age. Similarly, a dosage amount of insulin may be received by the AP application or algorithm from a user via a user interface. Other open-loop actions may also be implemented by adjusting user settings or the like in an AP application or algorithm. 
     Some examples of the disclosed device may be implemented, for example, using a storage medium, a computer-readable medium, or an article of manufacture which may store an instruction or a set of instructions that, if executed by a machine (i.e., processor or microcontroller), may cause the machine to perform a method and/or operation in accordance with examples of the disclosure. Such a machine may include, for example, any suitable processing platform, computing platform, computing device, processing device, computing system, processing system, computer, processor, or the like, and may be implemented using any suitable combination of hardware and/or software. The computer-readable medium or article may include, for example, any suitable type of memory unit, memory, memory article, memory medium, storage device, storage article, storage medium and/or storage unit, for example, memory (including non-transitory memory), removable or non-removable media, erasable or non-erasable media, writable or re-writable media, digital or analog media, hard disk, floppy disk, Compact Disk Read Only Memory (CD-ROM), Compact Disk Recordable (CD-R), Compact Disk Rewritable (CD-RW), optical disk, magnetic media, magneto-optical media, removable memory cards or disks, various types of Digital Versatile Disk (DVD), a tape, a cassette, or the like. The instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, programming code, and the like, implemented using any suitable high-level, low-level, object-oriented, visual, compiled and/or interpreted programming language. The non-transitory computer readable medium embodied programming code may cause a processor when executing the programming code to perform functions, such as those described herein. 
     Certain examples of the present disclosure were described above. It is, however, expressly noted that the present disclosure is not limited to those examples, but rather the intention is that additions and modifications to what was expressly described herein are also included within the scope of the disclosed examples. Moreover, it is to be understood that the features of the various examples described herein were not mutually exclusive and may exist in various combinations and permutations, even if such combinations or permutations were not made express herein, without departing from the spirit and scope of the disclosed examples. In fact, variations, modifications, and other implementations of what was described herein will occur to those of ordinary skill in the art without departing from the spirit and the scope of the disclosed examples. As such, the disclosed examples are not to be defined only by the preceding illustrative description. 
     Program aspects of the technology may be thought of as “products” or “articles of manufacture” typically in the form of executable code and/or associated data that is carried on or embodied in a type of non-transitory, machine readable medium. Storage type media include any or all of the tangible memory of the computers, processors or the like, or associated modules thereof, such as various semiconductor memories, tape drives, disk drives and the like, which may provide non-transitory storage at any time for the software programming. It is emphasized that the Abstract of the Disclosure is provided to allow a reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features are grouped together in a single example for streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed examples require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed example. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate example. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein,” respectively. Moreover, the terms “first,” “second,” “third,” and so forth, are used merely as labels and are not intended to impose numerical requirements on their objects. 
     The foregoing description of examples has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the present disclosure be limited not by this detailed description, but rather by the claims appended hereto. Future filed applications claiming priority to this application may claim the disclosed subject matter in a different manner and may generally include any set of one or more limitations as variously disclosed or otherwise demonstrated herein.