SYSTEM AND METHOD FOR PROVIDING AND MONITORING UV ILLUMINATION IN AN INTERIOR OF AN AIRCRAFT

Abstract

A system for providing and monitoring UV illumination in an interior of an aircraft includes at least one switchable UV light source; a light detector, responsive to visible light and UV light and configured for providing sensor outputs regarding detected light; and a controller for monitoring an operational status of the at least one switchable UV light source. The controller is configured to determine the operational status of the at least one switchable UV light source by comparing a first sensor output, provided by the light detector when the at least one switchable UV light source is activated, with a second sensor output, provided by the light detector when the at least one switchable UV light source is deactivated.

Claims

1. A system for providing and monitoring UV illumination in an interior of an aircraft, the system comprising: at least one switchable UV light source; a light detector, responsive to visible light and UV light and configured for providing sensor outputs regarding detected light; and a controller for monitoring an operational status of the at least one switchable UV light source, wherein the controller is configured to determine the operational status of the at least one switchable UV light source by comparing a first sensor output, provided by the light detector when the at least one switchable UV light source is activated, with a second sensor output, provided by the light detector when the at least one switchable UV light source is deactivated.

2. The system according to claim 1, wherein the light detector includes a photo sensor, which is sensitive to visible light, and a wavelength converting coating, with the wavelength converting coating emitting visible light when being excited by UV light.

3. The system according to claim 2, wherein the photo sensor comprises a plurality of detection channels, with the plurality of detection channels having different sensitivities to different ranges of electromagnetic radiation, wherein the photo sensor is in particular a multi-color photo sensor, with the plurality of detection channels having different sensitivities to different ranges of electromagnetic radiation in the range of visible light.

4. The system according to claim 2, wherein the wavelength converting coating comprises a light transmissive adhesive, in particular a translucent adhesive, and wherein a wavelength converting substance is adhered to the photo sensor via the light transmissive adhesive.

5. The system according to claim 4, wherein the wavelength converting substance includes a phosphor material that is at least one of Y.sub.2O.sub.3:Eu.sup.3+,Sr.sub.2Al.sub.6O.sub.11:Eu.sup.2+, BaMgAl.sub.10O.sub.17:Eu.sup.2+, and LaPO.sub.4:Ce.sup.3+,TB.sup.3+.

6. The system according to claim 4, wherein the wavelength converting substance, when excited with UV light, emits visible light in the range of between 600 nm and 650 nm.

7. The system according to claim 1, wherein the light detector includes quantum dots.

8. The system according to claim 1, wherein the system is configured for controlling the at least one switchable UV light source based on said monitoring of the operational status of the at least one switchable UV light source; wherein controlling the at least one switchable UV light source in particular includes adjusting an intensity of UV light, emitted by the at least one switchable UV light source, or adjusting a period of time, for which the at least one switchable UV light source is activated.

9. The system according to claim 1, wherein the system is configured for calculating an indication regarding a total amount of UV light, emitted by the at least one switchable UV light source over time, by accumulating the sensor outputs over time, and wherein the system is configured for providing a confirmation signal, when the indication regarding the total amount of UV light exceeds a predefined threshold; wherein the confirmation signal is in particular a visual confirmation signal and an acoustic confirmation signal, and/or wherein the system is configured for deactivating the at least one switchable UV light source, when the confirmation signal is issued.

10. An aircraft comprising: at least one system for providing and monitoring UV illumination according to claim 1, wherein the at least one system is located in at least one of a cockpit and a passenger cabin of the aircraft.

11. The aircraft of claim 10, wherein the at least one system is located in a lavatory or in a galley provided within the passenger cabin of the aircraft.

12. A method of providing and monitoring UV illumination in an interior of an aircraft, the method comprising: detecting light within the interior of the aircraft with a light detector, while at least one switchable UV light source is deactivated, and providing a first sensor output, which is a function of the detected light; activating the at least one switchable UV light source; detecting light within the interior of the aircraft with the light detector, while the at least one switchable UV light source is activated, and providing a second sensor output, which is a function of the detected light; and monitoring an operational status of the at least one switchable UV light source, wherein monitoring an operational status of the at least one switchable UV light source includes comparing the first sensor output with the second sensor output.

13. The method according to claim 12, wherein the light is detected by a light detector comprising at least one photo sensor, which is sensitive to visible light, and a wavelength converting coating, which emits visible light when it is excited by UV light.

14. The method according to claim 11, wherein the method includes: controlling the at least one switchable UV light source based on said monitoring of the operation status of the at least one switchable UV light source; wherein controlling the at least one switchable UV light source in particular includes adjusting an intensity of light, emitted by the at least one switchable UV light source, or adjusting a period of time, for which the at least one switchable UV light source is activated.

15. The method according to claim 12, wherein the method includes: calculating an indication regarding a total amount of UV light, emitted by the at least one switchable UV light source, by accumulating the sensor outputs over time and providing a confirmation signal, when the calculated indication exceeds a predefined threshold; wherein the confirmation signal is in particular a visual confirmation signal or an acoustic confirmation signal, or wherein the method includes deactivating the at least one switchable UV light source, when the confirmation signal has been issued.

16. The method according to claim 12, wherein the method includes: illuminating portions of a cockpit or of a passenger cabin of an aircraft with the UV light emitted by the at least one switchable UV light source.

17. The method of claim 16, wherein illuminating includes illuminating portions of at least one of a lavatory, a galley, and a passenger service unit, located within the passenger cabin, with the UV light.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0039] Further exemplary embodiments of the invention are described below with respect to the accompanying drawings, wherein:

[0040] FIG. 1 depicts an aircraft, in particular an air plane, in accordance with an exemplary embodiment of the invention in a schematic side view;

[0041] FIG. 2 depicts a schematic view of an overhead passenger service unit (PSU);

[0042] FIG. 3 depicts a schematic cut-open view of an aircraft in accordance with an exemplary embodiment of the invention, depicting a passenger cabin of the aircraft;

[0043] FIG. 4 depicts a schematic view of a system for providing and monitoring UV illumination according to an exemplary embodiment of the invention;

[0044] FIG. 5 shows a schematic cross-sectional view of a light detector, as it may be employed in a system according to an exemplary embodiment of the invention;

[0045] FIG. 6A shows the light intensities, detected by the light detector, as a function of the wavelength, when the at least one UV light source is switched off; and

[0046] FIG. 6B shows the light intensities, detected by the light detector, as a function of the wavelength, when the at least one UV light source is switched on.

DETAILED DESCRIPTION

[0047] FIG. 1 shows an aircraft 100, in particular an air plane, in accordance with an exemplary embodiment of the invention in a schematic side view. In the exemplary embodiment shown in FIG. 1, the aircraft 100 is a large passenger air plane, comprising a cockpit 103 and a passenger cabin 104 housing a plurality of passenger seats 106. The aircraft 100 may be a commercial passenger air plane, a private air plane, or a military aircraft. It is also possible that the system and method according to exemplary embodiments of the invention are implemented in a rotorcraft, such as a helicopter.

[0048] Passenger service units (PSU) 102 are arranged above the passenger seats 106.

[0049] In an exemplary configuration, in which the aircraft 100 comprises six passenger seats 106 per row (cf. FIG. 3, which will be discusses in more detail further below), each row of passenger seats 106 may have two passenger service units 102 associated therewith, one passenger service unit 102 assigned to the passenger seats 106 on the left side of a center aisle 114 and one passenger service unit 102 assigned to the passenger seats 106 on the right side of the center aisle 114.

[0050] FIG. 2 depicts a schematic view of an overhead passenger service unit (PSU) 102, which is arranged above the passengers of a single passenger row, as it is seen from the side of a passenger sitting on a passenger seat 106 below the overhead passenger service unit 102.

[0051] On the side, which is shown to the left in FIG. 2, the overhead passenger service unit 102 comprises a row of three adjustable reading lights 26a-26c, which are arranged next to each other.

[0052] Six electrical switches 27a-27c, 28a-28c are provided to the right side of the reading lights 26a-26c, a respective pair of two switches 27a-27c, 28a-28c next to each of the reading lights 26a-26c. One of the switches 27a-27c of each pair is configured for switching the adjacent reading light 26a-26c, and the second switch 28a-28c of each pair is configured for triggering a signal for calling cabin service personnel.

[0053] A row of three adjacent gaspers 29a-29c is provided next to the switches 27a-27c, 28a-28c.

[0054] Adjacent to the gaspers 29a-29c is a removable cover 40, which covers a cavity housing at least three oxygen masks (not shown). In the event of pressure loss within the cabin, the removable cover 40 will open, the oxygen masks will drop out of the cavity and each of the passengers, sitting below the overhead passenger service unit 102, may grasp one of the oxygen masks. The oxygen masks will be supplied with oxygen allowing the passengers to continue to breathe normally.

[0055] On the side opposite to the gaspers 29a-29c, a grid 42 is formed within overhead passenger service unit 102. A loudspeaker (not shown), which may be used for delivering acoustic announcements to the passengers, is arranged behind said grid 42.

[0056] Next to the grid 42, there is a display panel 44, which may be configured for selectively showing a plurality of visual signs (not shown), such as “non smoking” or “fasten you seat belt”. The display panel 44 may be illuminated from behind, in order to deliver visual information to the passengers sitting below the overhead passenger service unit 102.

[0057] FIG. 3 depicts a schematic cut-open view of an aircraft 100 in accordance with an exemplary embodiment of the invention, depicting a passenger cabin 104 of the aircraft 100, also referred to as aircraft passenger cabin 104 herein.

[0058] The aircraft passenger cabin 104 is equipped with a plurality of passenger seats 106. The passenger seats 106 are arranged next to each other forming a plurality of passenger seat rows. Each passenger seat row comprises two groups of passenger seats 106, respectively including three passenger seats 106. The two groups of passenger seats 106 are separated from each other by a center aisle 114, extending along a longitudinal axis A of the aircraft 1.

[0059] The aircraft passenger cabin 104 is further equipped with four lavatories 108a-108d. In the exemplary configuration depicted in FIG. 3, lavatories 108a-108d are provided at four locations within the aircraft passenger cabin 104. A first lavatory 108a is located at the front portside end of the aircraft passenger cabin 104, a second lavatory 108b is located at the front starboard end of the aircraft passenger cabin 104, a third lavatory 108c is located at the rear portside end of the aircraft passenger cabin 104, and a fourth lavatory 108d is located at the rear starboard end of the aircraft passenger cabin 104. Additionally or alternatively, lavatories 108a-108d may be provided at other locations of the aircraft passenger cabin 104 as well.

[0060] The aircraft passenger cabin 104 is further equipped with a galley 110, in order to allow for preparing meals and drinks for the passengers.

[0061] At least one of the lavatories 108a-108d and the galley 110 is provided with a system 2 for providing and monitoring UV illumination according to an exemplary embodiment of the invention.

[0062] In the exemplary embodiment depicted in FIG. 3, each lavatory 108a-108d and the galley 110 are provided with a system 2 for providing and monitoring UV illumination, respectively. However, exemplary embodiments of the invention also include aircraft 100 in which only one or any subset of the lavatories 108a-108d and the galley 110 are provided with a system 2 for providing and monitoring UV illumination.

[0063] Although not explicitly depicted in FIG. 3, systems 2 for providing and monitoring UV illumination according to exemplary embodiments of the invention may also be provided next to the passenger service units 102 (cf. FIGS. 1 and 2) for disinfecting said passenger service units 102 by illuminating the passenger service units 102 with UV light.

[0064] Systems 2 for providing and monitoring UV illumination according to exemplary embodiments may also be provided within the passenger cabin 104 for illuminating and disinfecting the passenger seats 106 located under the passenger service units 102. The systems 2 may, for example, be integrated into the passenger service units 102 or arranged next to the passenger service units 102.

[0065] Systems 2 for providing and monitoring UV illumination according to exemplary embodiments of the invention may also be provided within the cockpit 103 of the aircraft 100 for disinfecting surfaces touched by the pilots.

[0066] As UV light may be harmful to humans, in particular to the human eye, the systems 2 for providing and monitoring UV illumination according to exemplary embodiments provided within the passenger cabin 104 and/or within the cockpit 103 of the aircraft 100 may be activated only after the passengers and crew have disembarked after the flight, so that no humans are present within the aircraft 100.

[0067] Systems 2 for providing and monitoring UV illumination according to exemplary embodiments located in the lavatories 108a-108d, however, may also be activated during flight, when the lavatories 108a-108d are not occupied and the doors of the lavatories 108a-108d are closed, so that no UV light can exit the lavatories 108a-108d. Systems 2 located within the lavatories 108a-108d may, for example, be activated in regular time intervals or after a predefined number of passengers have used the respective lavatory 108a-108d, in order to ensure hygienic conditions within the lavatories during the flight.

[0068] A schematic view of a system 2 for providing and monitoring UV illumination according to an exemplary embodiment of the invention is depicted in FIG. 4.

[0069] The system 2 comprises at least one lighting device 4, which is configured for emitting visible light for illuminating the environment of the system 2, for example the lavatory 108a-108d or the galley 110. In the exemplary embodiment depicted in FIG. 4, two lighting devices 4 are shown. Each lighting device 4 may comprises at least one LED acting as a light source. Each lighting device 4 may in particular comprise a plurality of light sources 4a-4c, which are configured for emitting light of different colors. Such a configuration may allow for adjusting the color of the light, emitted by the at least one lighting device 4, by varying the intensity of the light emitted by the different light sources 4a-4c. In the exemplary embodiment of FIG. 4, each of the plurality of light sources 4a-4c comprises one or more LED(s).

[0070] The system 2 further comprises at least one switchable UV light source 6, which is configured for emitting UV light when activated. The UV light emitted by the at least one UV light source 6 may be directed to at least one surface for disinfecting said at least one surface, using the germicidal properties of UV light. The at least one UV light source 6 may include at least one LED, which is configured for emitting UV light.

[0071] The UV light emitted by the at least one UV light source 6 may have a wavelength of less than 400 nm, in particular a wavelength in the range of between 150 nm and 300 nm, more particularly a wavelength in the range of between 200 nm and 270 nm.

[0072] The system 2 further comprises a light detector 8 and a controller 10.

[0073] The light detector 8 is responsive to visible light and to UV light and is configured for providing sensor outputs, representing the detected light, to the controller 10.

[0074] The controller 10 is configured for monitoring an operational status of the at least one switchable UV light source, based on sensor outputs received from the light detector 8, and for selectively activating and deactivating the at least one lighting device and the at least one UV light source 6.

[0075] The controller 10 is in particular configured for activating the at least one UV light source 6 and for receiving a first sensor output, provided by the light detector 8 while the at least one UV light source 6 is activated. The controller 10 is further configured for deactivating the at least one switchable UV light source 6 and for receiving a second sensor output, which is provided by the light detector 8 while the at least one UV light source 6 is deactivated.

[0076] Alternatively, the controller 10 may be configured for receiving a first sensor output, which is provided by the light detector 8 while the at least one UV light source 6 is deactivated; for activating the at least one switchable UV light source 6; and for receiving a second sensor output, which is provided by the light detector 8 while the at least one UV light source 6 is activated.

[0077] The controller 10 monitors the operational status of the at least one switchable UV light source 6 by comparing the first and second sensor outputs with each other. The controller 10 is further configured for controlling the at least one switchable UV light source 6 based on said monitoring of the operational status of the at least one switchable UV light source 6.

[0078] Details of different modes of operation will be discussed in more detail further below.

[0079] FIG. 5 shows a schematic cross-sectional view of a light detector 8, as it may be employed in a system 2 according to an exemplary embodiment of the invention.

[0080] The light detector 8 includes a photo sensor 80 sensitive to visible light, which is mounted to a support 81, for example to a printed circuit board 81.

[0081] The photo sensor 80 may in particular be configured for providing spectral information about the light detected by the photo sensor 80, i.e. the photo sensor 80 may provide information about the intensity of the detected light as a function of the wavelength of the detected light.

[0082] The photo sensor 80, for example, may comprise a plurality of detection channels, with the plurality of detection channels having different sensitivities to different ranges of electromagnetic radiation, so that the photo sensor 80 is capable to provide separate intensity information for each range of electromagnetic radiation, respectively.

[0083] The photo sensor 80 may, for example, be a multi-color photo sensor, wherein the plurality of detection channels have different sensitivities to different ranges of electromagnetic radiation in the range of visible light, e.g. in the range between 350 nm and 800 nm.

[0084] In order to allow the photo sensor 80 to detect UV light, the photo sensor 80 may be at least partially covered with a wavelength converting coating 82, which is configured for emitting visible light when it is excited by UV light.

[0085] In the embodiment depicted in FIG. 5, the wavelength converting coating 82 includes a translucent adhesive 84, which is applied to an upper surface of the photo sensor 80 on a side opposite to the support 81, and a wavelength converting substance 86, which is applied to a side of the adhesive 84 facing away from the photo sensor 80.

[0086] The wavelength converting substance 86 may cover the upper surface of the adhesive 84 facing away from the photo sensor 80 completely. Alternatively, the wavelength converting substance 86 may cover the upper surface of the adhesive 84 only partly, in order to allow visible light to pass through portions of the translucent adhesive 84, which are not covered by the wavelength converting substance 86, in an unimpeded manner.

[0087] In an alternative embodiment, which is not explicitly shown in the figures, the light transmissive adhesive 84 may include a thin quartz window that encapsulates the wavelength converting substance 86 underneath.

[0088] The wavelength converting substance 86 may include a phosphor material, in particular at least one of Y2O3:Eu3+, Sr2AL6O11:Eu2+, BaMgAl10O17:Eu2+, and LaPO4:Ce3+,TB3+. These phosphor materials have been found as well suited for converting UV light into visible light.

[0089] The wavelength of the visible light, into which the UV light is converted, depends on the material used for the wavelength converting substance 86. In other words, the wavelength of the visible light, into which the UV light is converted, may be selected by choosing the material of the wavelength converting substance 86.

[0090] Y2O3:Eu3+, for example, converts UV light very efficiently into visible red light having a wavelength of approximately 611 nm. Sr2AL6O11:Eu2+ and BaMgAl10O17:Eu2+ convert UV light to visible blue light, and LaPO4:Ce3+,TB3+ emits visible green light, when it is excited by UV light.

[0091] All these materials emit a very narrow spectrum of visible light, i.e. a spectrum of visible light in which at least 90% of the light is emitted within a range of wavelengths having a width of 50 nm. Providing such a narrow spectrum of visible light may allow for reliably detecting and identifying the converted visible light, which is emitted by the wavelength converting substance 86, when it is excited by UV light.

[0092] Alternatively or additionally to a phosphor material, as it has been described before, the wavelength converting substance 86 may include quantum dots for converting the UV light, emitted by the at least one UV light source 6, into visible light, which is detectable by the photo sensor 80.

[0093] FIGS. 6A and 6B illustrate examples of light intensities I, plotted on the vertical axis, as detected by the light detector 8 when the at least one UV light source 6 is switched off (FIG. 6A) and when the at least one UV light source 6 is switched on (FIG. 6B). The light intensities I are depicted as a function of the wavelength λ, which is plotted on the horizontal axis.

[0094] FIG. 6A depicts the spectral distribution of the light emitted by the at least one lighting device 4 comprising three peaks 91, 92, 93, namely a first peak 91 centered at approximately 465 nm corresponding to blue light, a second peak 92 centered at approximately 555 nm corresponding to green light, and a third peak 93 centered at approximately 611 nm corresponding to red light.

[0095] A spectral distribution, as it is depicted in FIG. 6A, is detected and stored when the at least one UV light source 6 is deactivated. In addition to light emitted by the at least one lighting device 4 provided within the aircraft 100, the spectral distribution may include further spectral components (not shown), which may result from external light, in particular sun light, which enters through windows into the aircraft 100.

[0096] FIG. 6B depicts the spectral distribution of the light detected by the light detector 8 when the at least one UV light source 6 is activated and the UV light, emitted by the at least one UV light source 6, is converted into visible light, in particular into red light having a wavelength spectrum centered around 611 nm, by Y2O3:Eu3+, which has been applied to the surface of the photo sensor 80 as the wavelength converting substance 86.

[0097] The comparison of FIGS. 6A and 6B shows that the first and second peaks 91, 92, corresponding to blue light and green light, do not change when the at least one UV light source 6 is activated. The height of the third peak 93, corresponding to the intensity of detected red light, however, increases considerably when the at least one UV light source 6 is activated. In the examples depicted in FIGS. 6A and 6B, the height of the third peak 93 almost doubles when the at least one UV light source 6 is activated.

[0098] This drastic increase ΔI of the detected intensity of red light allows the controller 10 to reliably confirm that the at least one UV light source 6 is activated. It further allows the controller 10 to determine an indication regarding the intensity of the UV light, emitted by the at least one UV light source 6, from the change of the height of the third peak 93.

[0099] In case a different material than Y2O3:Eu3+ is employed as the wavelength converting substance 86 for converting the UV light, emitted by the least one UV light source 6, into visible light, the first peak 91 and/or the second peak 92, corresponding to blue light and green light, respectively, may increase instead of or in addition to the third peak 93.

[0100] In particular, if Sr2AL6O11:Eu2+ or BaMgAl10O17:Eu2+ are included in the wavelength converting substance 86, the first peak 91 corresponding to blue light will increase, and the second peak 92 corresponding to green light will increase if LaPO4:Ce3+,TB3+ is included in the wavelength converting substance 86.

[0101] By comparing a first sensor output, provided by the light detector 8 when the at least one switchable UV light source 6 is activated, as it its depicted in FIG. 6B, with a second sensor output, which is provided by the light detector 8 when the at least one switchable UV light source 6 is deactivated, as it is depicted in FIG. 6A, the controller 10 is capable to reliably determine whether the at least one switchable UV light source 6 has been activated. This may be true even under varying ambient light conditions. The ambient light conditions may, for example, change due to a change of external light, in particular sun light, shining into the aircraft 100.

[0102] The controller 10 is further capable to determine an indication regarding the intensity of the UV light and to control the operation of the at least one UV light source 6 based on the information about the intensity of the UV light, provided by the light detector 8.

[0103] Controlling the at least one switchable UV light source 6 may include adjusting the intensity of UV light, emitted by the at least one switchable UV light source 6, by controlling the operation of the at least one UV light source 6. The intensity of UV light, emitted by the at least one UV light source 6, may for example be adjusted so that the intensity of the UV light exceeds a predefined minimum intensity threshold and/or so that the intensity does not exceed a predefined maximum intensity threshold.

[0104] Controlling the at least one switchable UV light source 6 may also include adjusting a period of time, for which the at least one switchable UV light source 6 is activated. The period of time, for which the at least one switchable UV light source 6 is activated, may in particular be changed as a function of the detected intensity of UV light.

[0105] For example, the period of time, for which the at least one switchable UV light source 6 is activated, may be extended when the detected UV intensity is low, and the period of time, for which the at least one switchable UV light source 6 is activated, may be shortened when the detected UV intensity is high. In this way, a substantially constant disinfection effect may be achieved, independent of potential changes in the intensity of the UV light, which may occur for example due to aging of the at least one UV light source 6.

[0106] The controller 10 may, for example, be configured for calculating an indication regarding a total amount of UV light, which is emitted by the at least one switchable UV light source 6 over time, by accumulating the sensor outputs over time. The controller 10 may further be configured for providing a confirmation signal, when the indication exceeds a predefined threshold. The confirmation signal may include a visual and/or an acoustic signal. The confirmation signal may also include a control signal, which causes deactivating the at least one switchable UV light source.

[0107] Such a configuration may allow for indicating that an amount of UV light, which is considered sufficient for reliably disinfecting at least one surface by illumination with UV light, has been detected. It may further allow for automatically deactivating the at least one switchable UV light source after a sufficient amount of UV light has been detected. This may allow for a reliable automatic disinfection of surfaces within the aircraft 100.

[0108] Optionally, the confirmation signal may further include a signal which is transmitted to a board computer of the aircraft 100 and/or a log signal, which allows for logging the operation of the at least one UV light source 6. Logging the operation of the at least one UV light source 6 may allow for documenting that surfaces within the aircraft 100 have been disinfected regularly and sufficiently.

[0109] Logging the operation of the at least one UV light source 6 may further allow for monitoring the periods of operational time of the at least one UV light source 6 needed for sufficient disinfection. An increase of the periods of operational time needed for sufficient disinfection may indicate an aging of the at least one UV light source 6. In consequence, an aged UV light source 6 may be replaced in good time before it completely fails or becomes too weak for allowing a reliable disinfection.

[0110] While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.