Patent Publication Number: US-11647794-B2

Title: System and method of obtaining smoking topography data

Description:
RELATED APPLICATION 
     This application is a Continuation of U.S. application Ser. No. 17/000,444, filed on Aug. 24, 2020, which is a Continuation of U.S. application Ser. No. 16/715,321, filed on Dec. 16, 2019, which is a Continuation of U.S. application Ser. No. 14/205,717, filed on Mar. 12, 2014, which claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 61/800,226 filed on Mar. 15, 2013, the content of each of which is hereby incorporated by reference in its entirety. 
    
    
     FIELD 
     This disclosure relates to an electronic aerosol smoking article, and particularly to a system and method of obtaining smoking topography data from an electronic smoking article. 
     WORKING ENVIRONMENT 
     Smoking articles including electronic cigarettes or e-cigarettes use a liquid as the aerosol-forming substrate reduce secondhand smoke, while permitting a smoker to selectively suspend and reinitiate smoking. These devices can include a cartridge that contains the aerosol forming substrate. The substrate can come in various forms such as a solid or liquid and releases an aerosol gas to the smoker following the appropriate application of heat through a heating element. The heating element is powered through a power supply, such as a battery. The heating of the aerosol substrate is triggered via e-puff sequence initiated by the user. 
     Various systems have been described which collect data based on the smoking topography of the individual. For example, US 2012/0291791 discloses a nicotine delivery reduction system having a breath monitor that tracks nicotine solution usage, usage frequency, and breath characteristics. A flow controller is used to regulate the levels of nicotine or nicotine solution provided to a user based on monitored user habits and characteristics. US 2011/0036346 discloses a personal inhalation device that includes a logic circuit that can be programmed to limit an amount of nicotine media atomized during a puff, and the minimum time interval between activations of the atomizing device, for example. The logic circuit can be programmed to retain device operation information such as puffs per day, puffs per minute, cartridges used, average use, and other usage information as desired. The collected data is stored in memory and can be later downloaded to an external device. 
     US 2011/0265806 is directed to an electronic smoking article that includes a controller that carries out various operations on the device and a memory that stores instructions to be executed by the controller and may store usage information, product information, and user information. For example, the usage information can include a smoking liquid level in the container, how many containers have been consumed, and an amount of nicotine consumed. The product information can include a model number and serial number; and the user information can include name, sex, age, address, job, educational background, interests, and hobbies among the information. This data can be stored in memory until downloaded through any suitable wired or wireless connection. 
     SUMMARY 
     The exemplary embodiments of the present disclosure provide several advantages over known systems in that the smoking topography device of the present disclosure includes a processor that is configured to look at shifts in battery voltage to determine when smoking events occur. That is, each puff event on an electronic cigarette drains a portion of charge from the battery, which causes a shift in the battery voltage over the duration of the puff event. Thus, the timing, length, and duration of the puff events can be monitored and recorded around these voltage shifts. Data is collected during the smoking events to monitor device operation and user habits. The data is collected and stored in memory in a structured data pattern and can be later transferred to an external device over a USB or wireless connection for further analysis or processing. 
     The data can be recorded in a hexadecimal format or other suitable format as desired, output through wired or wireless means to an external device and used in clinical studies to monitor smoking topography, and/or to inform smoker of usage. Further, the data can be used to optimize device performance, or calibrate the device based on smoker&#39;s usage patterns. For example, the data may be used to optimize device functions such as power modulation, fluid delivery rate, battery voltage, so as to optimize sensory experience and/or extend battery life or heater life. 
     An exemplary first embodiment is directed to an electronic aerosol smoking article, comprising: at least one sensor configured to measure user interaction with the smoking article; a processor configured to detect a smoking event based an output of the at least one sensor, collect data associated with the smoking event, and arrange the data in a pattern that associates the smoking event to shifts in battery voltage; and memory configured to store the data pattern in a structured multi-byte format. 
     An exemplary second embodiment is directed to a smoking topography circuit of an electronic aerosol smoking article, the circuit comprising: at least one sensor configured to detect user interaction with the smoking article; a battery configured to supply power to the smoking article; a processor configured to detect a smoking event based on output of the at least one sensor, collect data associated with the smoking event, and arrange the data in a pattern that associates the smoking event to shifts in battery voltage; and memory configured to store the data pattern in a structured multi-byte format. 
     An exemplary third embodiment of the present disclosure is directed to method of generating smoking topography data for an electronic aerosol smoking article including at least a battery, a heating element, and a processor, the method comprising: determining an occurrence of a smoking event through at least one sensor that measures user interaction with the smoking article; capturing a battery voltage at a start and an end of a smoking event; and generating a data structure that defines the smoking event with respect to a change in battery voltage at the start and end of the smoking event. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Exemplary embodiments of the present disclosure are described in more detail with reference to the attached drawings. 
         FIG.  1    illustrates an exemplary electronic aerosol smoking article in accordance with an exemplary embodiment of the present disclosure. 
         FIG.  2    illustrates features of a smoking topography device (STD)  112  in accordance with an exemplary embodiment of the present disclosure. 
         FIG.  3    illustrates a method for generating smoking topography data in accordance with an exemplary embodiment of the present disclosure. 
         FIG.  4    illustrates a data format and structure in accordance with an exemplary embodiment of the present disclosure. 
         FIG.  5    illustrates an example of smoking topography data as recorded in memory for a single smoking event in accordance with the method as shown in  FIG.  3    in accordance with an exemplary embodiment of the present disclosure. 
         FIG.  6    illustrates an example of smoking topography data recorded in memory for consecutive smoking events in accordance with the method illustrated in  FIG.  3    in accordance with an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments of the present disclosure are directed to an electronic aerosol smoking article having a capability to collect, store, and transmit smoking topography data to an external device such as a computer, workstation, processor, or other suitable device as desired. The smoking article includes on board non-volatile memory (e.g., flash memory) and a processor, such as a programmable logic device, configured to collect smoking topography data such as puff count, puff duration, puff volume and air flow through various integrated sensors. The processor can be configured to transmit the collected data over a wired or wireless interface, such as Bluetooth or a Universal Serial Bus (USB) connection, to the external device. 
       FIG.  1    illustrates an exemplary electronic smoking article (e.g., electronic aerosol smoking device (EASD))  100  in accordance with an exemplary embodiment of the present disclosure. The EASD  100  includes a housing  102  having a first end  104  and a second end  106 . The first end  104  includes a mouthpiece  108  configured to be engaged by the mouth of a user. The first end  104  also includes an aerosol forming substrate  110  disposed therein and connected to release aerosol vapors or gas to the user via the mouthpiece  108 . The aerosol-forming substrate  110  can include a material comprised of tobacco and volatile tobacco flavored compounds that are released from the substrate upon heating. The aerosol-forming substrate  110  can be implemented in any of a number of known forms. For example, the aerosol-forming substrate  110  can be a solid substrate comprised of any combination of: powder, granules, pellets, shreds, spaghettis, strips or sheets, all of which can include one or more of: herb leaf, tobacco leaf, fragments of tobacco ribs, reconstituted tobacco, homogenized tobacco, extruded tobacco, and expanded tobacco. The solid substrates can be provided on or embedded in any type of suitable thermally stable carrier. In an exemplary embodiment, the aerosol-forming substrate can be a liquid substrate that is retained in any type of known container or porous carrier material. In another exemplary embodiment, the aerosol-forming substrate  110  can be a gas substrate, or any combination of the exemplary aerosol-forming substrates already described. 
     The second end  106  of the housing  102  can include a smoking topography device  112 . The smoking topography device  112  can be connected to the aerosol-forming substrate  110  in the first end  104  of the housing to control the release of aerosol from the aerosol-forming substrate  104  and to collect data associated with the release of the aerosol and use of the EASD  100 . 
       FIG.  2    illustrates features of the smoking topography device (STD)  112  in accordance with an exemplary embodiment of the present disclosure. 
     As shown in  FIG.  2   , the STD  112  includes a processor  200 , a plurality of sensors  202 , a power supply  204 , a heating element  206 , a charging circuit  208 , and a communications link  210 . The processor  200  can be implemented as a programmable logic circuit, a multi-functional logic chip (MFL), or any other suitable programmable controller or microcontroller device as desired. The processor  200  can be configured to detect a smoking event based on a change in the battery voltage, control the heating element  206  to heat the aerosol-forming substrate  110 , and generate a data set based on smoking topography data collected during the smoking event. In an exemplary embodiment, one smoking event can include a puff request event in which the user engages the first end  104  of the housing  102  to effect release of aerosol gas from the mouthpiece  108 . Another smoking event can include a puff release event in which the user disengages the first end  104  of the housing  102  thereby stopping the release of aerosol gas from the mouthpiece  108 . In another exemplary embodiment, the smoking event can include a combination of a puff request event and a puff release event. 
     The processor  200  can be configured to include an analog-to-digital (A/D) converter  212  and memory  214 . The analog-to-digital (A/D) converter  212  that converts analog data received from any of the plurality of sensors and converts it to digital data. The memory  214 , such as a non-volatile Serial Flash memory or other suitable memory device as desired, is configured to store the smoker behavior data converted by the A/D converter  212 . The memory can be of sufficient size to store the collected data in multiple data bytes and in a hexadecimal format. The processor  200  is configured to control all operations of the STD  112 , such as triggering the heating element  206  to heat the aerosol forming substrate  110 , on/off states of the LEDs  216 , and other operations to be discussed in further detail below. For example, the processor  200  can be configured to include a system clock (CLK) for tracking the time passed since the initialization of the EASD  100 . The processor  200  can also be configured to include various counters (Timer 0 , Timer 1 , Timer 2 , . . . , TimerX) for recording a length, time interval, or duration of a smoking event, a non-smoking time interval between smoking events, or a time after initialization of the EASD  100  and leading up to a smoking event. 
     The processor  200  can include various other counters (CNT), which can be used to monitor and/or track a number of smoking events (EN) that have occurred. Moreover, the processor can be configured to include any of a number of registers (REG) that can track a status of the system or various components in the system, such as the sensors  202 . For example, a battery register (BATTREG) can be configured to record a status of the battery voltage such that a high (1) or low (0) status is recorded based on the voltage level in comparison to a predetermined threshold (e.g., 3.3V). In another example, a smoking status register (SSREG) can be configured to record a status of the EASD  100  during a smoking event as a puff begin status or puff release status. The processor can include a Start of Puff Cigarette Battery Voltage Counts register (SPVCREG) that records a value of the battery voltage level at the instant a puff start event is detected. The processor  200  can also include an End of Puff Cigarette Battery Voltage Count register (EPVCREG) that records a value of the battery voltage level at the instant a puff release event is detected. It should be understood, that any number of registers can be employed to obtain and/or collect data necessary or desired in tracking or monitoring smoking topography. 
     The plurality of sensors  202  can be configured to measure various functions and operations of the device during a smoking event. The data can include smoking puff length, puff frequency, puff power activity, puff count, air flow rate, or any other smoking topography data related to the smoker as desired. In an exemplary embodiment of the present disclosure, the sensors  200  can be integrated into the structure of the processor  200 . In another exemplary embodiment, the at least one of the sensors  200  can be external to the processor. 
     The power supply  204  can be implemented as a battery or power cell, which supplies power to the heating element  206 . The power supply  204  can be in the form of a Lithium-ion battery or any suitable variant thereof. In another exemplary embodiment, the power component  204  can include a Nickel-metal hydride battery or a Nickel cadmium battery or fuel cell. The power supply  204  can be recharged via the charging circuit  208 . The charging circuit  208  can be configured to receive power for charging the battery  204  through the communication link  210 . Via power converters or other suitable devices, the power supply  204  can be configured to provide power at an appropriate voltage level (e.g., 3.3V) to the processor  200 . 
     The heating element  206  can be configured to include a single element or an array of heating elements. The heating elements  206  can be arranged within the EASD housing  102  so that appropriate heat can be applied to the aerosol-forming substrate. The heating element  206  can include an electrically resistive material such as semiconductor materials including doped ceramics, electrically conductive ceramics, carbon, graphite, metals, metal alloys, composite materials made of ceramic and metallic materials, or any other suitable electrically resistive material as desired. In an exemplary embodiment, the heating element  206  may comprise an electrically resistive coil which cooperates with a filamentary wick, such as described in U.S. published application 2013/0192615. In another exemplary embodiment, the heating element  206  can include an infra-red heating element as described in U.S. Pat. No. 5,514,630 (hereby incorporated by reference in its entirety), an inductive heating element as described in U.S. Pat. No. 5,613,505 (herein incorporated by reference in its entirety), a heat sink or heat reservoir as described in EP 0 857, 431, or any other suitable heating component as desired. The heat reservoir can be comprised of a material capable of absorbing and storing heat and releasing the heat over time to the aerosol-forming substrate. The heat sink or heat reservoir can be in direct contact with the aerosol-forming substrate and can transfer the stored heat directly to the substrate. In other known implementations, the heat stored in the heat sink or heat reservoir can be transferred to the aerosol-forming substrate via a heat conductor, such as a metallic tube, as described in WO 2008/0154441. In any exemplary configuration, the heating element  206  is configured to trigger a heating cycle of the aerosol-forming substrate  110  based on a control signal received from the processor  200 . 
     The communication link  210  can be configured to provide a bi-directional wired or wireless connection to an external device. In a wired configuration, the communication link  210  can be a Universal Serial Bus (USB), a Recommended Standard 232 (RS-232) family of standards. The wired configuration can provide bi-directional communication and also power up to 5V DC. In a wireless configuration, the communication link  210  can be implemented as Bluetooth, Infrared Data Association (IrDA), radio-frequency (RF), cellular, or other suitable wireless communication standard as desired. The communication link  208  is connected to the processor  200  to transfer smoking topography data to the external device and/or the transfer configuration data to the processor  200 . The communication link  210  can be configured to allow for bidirectional communication of user data, control data, and/or configuration data between the STD  112  and an external device or processor. With regard to the configuration and control data, the processor  200  can be configured to be specially programmed and/or configured to execute a process recorded on a non-transitory computer-readable recording medium, such as a hard disk drive, flash memory, optical memory or any other type of non-volatile memory as desired. The executable data for the process being transferrable or transferred to the processor  200  via the communication link  208 . 
     In an exemplary embodiment, the STD  112  can be configured to include at least one light emitting diode (LED)  218 , which provides a visual indication to a user regarding an operational status of the EASD  100 . For example, the LEDs can be visualized on an outer portion of the housing  102  and provide a visual indication of a charging status of the battery  202 , the smoking status, or any other suitable operational or functional characteristic of the EASD  100  or STD  112  as desired. It should be understood, that the LED can be configured to emit any suitable color, be in any suitable shape, or provide an output in any suitable pattern as desired to provide the appropriate information to the user. 
     The STD  112  can also include a key/switch circuit  220  that provides secure access to system/configuration data and/or smoking topography data stored in the processor  200 . 
     In another exemplary embodiment the STD  112  can include a circuit debugger  222  that allows for resolving errors in the processing operation of the processor  200  due to corrupted user data, configuration data, or system data as needed. 
     The STD  112  can be formed on a multi-layer printed circuit board (PCB). The circuit board can be of a suitable size and length, such as 25 mm×8 mm, so that it can be fully enclosed in the housing  102  of the EASD  100 . 
     The STD  112  can be configured to include two modes of operation, which include a Pre-Heat Mode and a Steady Smoking Mode. 
     When a user starts to smoke (e.g., a smoking event), the heating element is initially cool. Therefore, the heating element  206  can specify to have a full power supplied so that the temperature can be increased as fast as possible. Once the heater is pre-heated, the power supplied to the heating element  206  can be scaled back. In an exemplary embodiment, a pulse-width modulated (PWM) pulse can be provided to the heater to maintain constant power scheme can be used to maintain constant power and temperature in order to extend the life of the heater. Parameters of the PWM pulse can be adjusted through an application interface of a computer via the communication link  210  to select a desired power level for the Steady State Smoking Mode. For example, in an exemplary embodiment in which the pulse width has a large duty cycle, the average output power on the heater would also be larger. The time specified for completing a Pre-Heat Mode depends on the temperature of the heating element just prior to the start of the Pre-Heat Mode. The Pre-Heat time can be adjusted by setting the value of a counter (Timer 0 ), which specifies an idle time between two smoking events. 
     The communication link  210  can also be used to configure the STD  112 , such that different voltage battery levels have different times for completing the Pre-Heat Mode and different PWM pulse values. In an exemplary embodiment, the battery voltage levels can be divided into four ranges as follows: (1) 3.3V-3.5V, (2) 3.5V-3.7V, (3) 3.7V-3.9V, and (4) 3.9V-4.1V. Variable resistors on the PCB board of the STD  112  can be tuned to control the voltage level used by the electronic cigarette device. In an exemplary embodiment of the present disclosure, different pre-heat times can PWM pulse values can be set in the PC interface via the communication link  210  to maintain a desired smoking quality at any of a number of voltage levels. Because the PWM power in one voltage range should be equal to the PWM power in another voltage range, once parameters in a range (1) are determined, for example, the parameters of the other voltage ranges can be derived using the following: 
                     P     PWM   ⁡     (     1   ⁢   st   ⁢           ⁢   voltage   ⁢           ⁢   range     )         =     P     PWM   ⁡     (     2   ⁢   nd   ⁢           ⁢   voltage   ⁢           ⁢   range     )                 (   1   )               P   =       V   2     R             (   2   )               
where P is the power of the PWM pulse, V is the average voltage of the PWM pulse, and R is the resistance or value of the period of the PWM pulse.
 
     The duration of the Idle Time is a factor in determining an optimal Pre-Heat time. A longer idle time results in the heater being cooler just prior to starting the Pre-heat Mode, which means that a longer pre-heat time should be specified. 
       FIG.  3    illustrates a method for generating smoking topography data in accordance with an exemplary embodiment of the present disclosure. As shown in  FIG.  3   , at step  300 , when the STD  112  is powered on or reset, the system program is loaded from memory and initialized. Once the system program and/or configuration data is loaded from memory  214 , the processor is provided with at least date information for the system clock. 
     At step  302 , and following system start, the idle time counter (Timer 0 ) and the system clock (CLK) are initialized. Timer 0  is set to Pre-Heat Mode idle time set by the user, or is initialized to a default value. The processor also sets at least one general purpose input/output (GPIO) pin as an interrupt (INT) input. For example, in an exemplary embodiment the processor  200  can have a pin (e.g., a Port C 1 ) connected to an output of an air flow sensor. The air flow sensor can be configured to detect a change in the air flow based on a predetermined threshold. This change indicates that a user has engaged or disengaged the mouthpiece  108  of the EASD  100  and initiated or stopped smoking sequence during a puff start event or puff release event, respectively. When the air flow sensor output is connected to a GPIO pin set as an interrupt (Int 1 ), a high or flow sensor output causes the processor to generate interrupt INT 1 . 
     At step  304 , the processor  200  monitors the GPIO pin. If the GPIO pin is low then the sensor has not detected puff start event or flow. At step  306 , when no puff start event is detected, the Timer 0  value is 0.1 s, then an interrupt for Timer 0  is generated and at step  308 , the Timer 0  value is incremented. Processing then returns to step  304  and continues to monitor the GPIO pin for a puff start event. 
     When the air flow sensor output is high indicating a puff start event, then the interrupt INT 1  is generated. Once the interrupt INT 1  is generated, at step  310  the processor  200  captures a value of the battery voltage and records this value as the Start of Puff Cigarette Battery Voltage Count (SPVC). The processor  200  also initiates a second counter (Timer 1 ), which is used to measure the length of the puff or the time interval from the puff start event to the puff release event. The processor  200  also collects and records a value of the system clock. 
     At step  312 , the processor  200  monitors the GPIO pin connected to the airflow sensor  202 . Specifically, the GPIO pin is monitored for a low output, which means that the air flow sensor has detected that the air flow at the mouthpiece  108  has dropped below the predetermined threshold. A low output from the airflow sensor  202  is an indication that a puff release event has occurred. At step  314 , when the GPIO pin maintains a high value then the Timer 1  is incremented and processing returns to step  312  to again monitor the GPIO pin. 
     Returning to step  312 , when the airflow sensor output is low (0), an interrupt INT 2  at the GPIO pin is generated. Upon the generation of INT 2 , the processor  200  stops the Timer 1  and records the value of the Timer 1  as the Time of Event (TOE) or puff length (Step  316 ). The processor  200  then starts a third counter (Timer 2 ), which measures the puff release length or the non-smoking time interval between the puff release event and a puff start event of the next smoking event. The processor  200  collects the value of the battery voltage and records this value as the End of Puff Battery Voltage Count (EPVC). The processor  200  also collects and records a value of the system clock. 
     Processing continues at step  318 , where the GPIO pin is again monitored for a high value indicating another puff start event. If no puff start event is detected, at step  318  the processor  200  increments Timer 2  by 1 (step  320 ). If after incrementing, the value of Timer 2  is above a predetermined value then the processor  200  will determine that no further puff events will occur and in order to conserve battery charge will turn off the EASD  100  or go into a sleep mode (step  322 ). If the value of the Timer 2  is otherwise below the threshold value, then processing returns to step  316 . 
     If at step  318 , the processor  200  detects a next puff start event, then the value of the Timer 2  is collected and recorded, and processing returns to step  312 . 
       FIG.  4    illustrates a data format and structure in accordance with an exemplary embodiment of the present disclosure. 
     As already discussed, the processor  200  collects numerous amounts of data related to the smoking topography through the use of registers and counters, each having a specified bit resolutions. The collected data is transferred to memory  214 , where it is recorded in a specified data format and structure. The data is recorded in a corresponding bit pattern such that each byte of data includes a number of bits assigned to at least one specified data value. The multi-byte data structure being stored in a hexadecimal format. As shown in  FIG.  4   , the data format can include multiple bytes, the first data byte (8 bits) including data values that specify the event number (EN), battery status (BS), and smoking status (SS). The second data byte can include a value corresponding to the SPVC value stoned in the SPVCREG. The third data byte can include EPVC value stored in the EPVCREG. A combination of the fourth and fifth data bytes can be used to record the time of count value as stored in the TOEREG value, and a portion of the fifth data byte along with the sixth through eighth can be used to record a value of the system clock CLKREG. As shown, each data value has a corresponding bit resolution, however, it should be understood that the bit resolution for each data value can be adjusted as desired for suitable monitoring of smoking topography in a specified implementation. 
       FIG.  5    illustrates an example of smoking topography data as recorded in memory for a single smoking event in accordance with the exemplary method shown in  FIG.  3    of the present disclosure. In the context of this example, the single smoking event includes one puff start event and puff release event pair. As shown in  FIG.  5   , for the single smoking event the processor  200  collected an SPVC value of 4.35V, and EPVC value of 3.75V, a TOE value of 1.3 seconds, and a system clock value of 1 hour. Moreover, the battery status was identified as normal (&gt;3V) and the smoking status identified as a puff status (10). The foregoing data can be recorded in a hexadecimal format and output at a value of 29 E0 6D 02 28 00 0E 10. 
       FIG.  6    illustrates an example of smoking topography data recorded in memory  214  for consecutive smoking events in accordance with the exemplary method illustrated in  FIG.  3    of the present disclosure. In the context of this example, consecutive smoking events include multiple and consecutive puff start and puff release event pairs. As shown in  FIG.  6   , for the first smoking event the processor  200  collected an SPVC value of 4.35V, and EPVC value of 3.75V, a TOE value of 1.3 seconds, and a system clock value of 1 hour. Moreover, the battery status was identified as normal (&gt;3V) and the smoking status identified as a puff status (10). The data of the first smoking event is recorded in a hexadecimal format and output at a value of 29 E0 6D 02 28 00 0E 10. 
     For the second smoking event, the processor  200  collected an SPVC value of 0V, and EPVC value of 0V, a TOE value of 0.93 seconds, and a system clock value of 1 hour 1 second. Moreover, the battery status was identified as normal (&gt;3V) and the smoking status identified as a puff release status (01). The data of the second smoking event can be recorded in a hexadecimal format and output at a value of 64 00 00 01 7 40 0E 11. For the third smoking event, the processor  200  collected an SPVC value of 4.15V, and EPVC value of 3.85V, a TOE value of 1.88 seconds, and a system clock value of 1 hour 3 seconds. Moreover, the battery status was identified as normal (&gt;3V) and the smoking status identified as a puff status (10). The data of the third smoking event can be recorded in a hexadecimal format and output at a value of 69 C9 6F 02 F0 00 0E 13. 
     The teachings herein are applicable to all forms of electronic smoking articles, such as electronic cigarettes, cigars, pipes, hookas, and other smoking articles as desired, regardless of their size and shape. 
     While the disclosure has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the disclosure is not limited to the disclosed exemplary embodiments. Other variations to the disclosed exemplary embodiments can be understood and effected by those skilled in the art and practicing the claimed disclosure, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference symbols in the claims should not be construed as limiting the scope. 
     Thus, it will be appreciated by those skilled in the art that the present disclosure can be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restricted. The scope of the disclosure is indicated by the appended claims rather than the foregoing description and all changes that come within the meaning and range and equivalence thereof are intended to be embraced therein.