阅读说明：本技术 天然海绵设施积水的实时预警监测系统及方法 (Real-time early warning and monitoring system and method for accumulated water of natural sponge facility ) 是由 李孟 李嘉炜 张一博 于 2021-09-10 设计创作，主要内容包括：本发明公开了一种天然海绵设施积水的实时预警监测系统及方法,其中系统中的实时预警监测平台包括设置在海绵设施内设有呈纵向铺设的多级监测单元,多级监测单元的纵向距离呈递减式；每个监测单元包括多路并联的光纤光栅传感器组,单个支路中相邻光纤光栅传感器之间的间距相等,相邻支路之间的距离大于单个支路中相邻光纤光栅传感器之间的距离。本发明利用光纤传感技术对土壤中雨水下渗速率进行测量,从而间接反映当前城市中天然海绵设施中的积水状况,做出相应预警措施。(The invention discloses a real-time early warning and monitoring system and a real-time early warning and monitoring method for water accumulation of a natural sponge facility, wherein a real-time early warning and monitoring platform in the system comprises a plurality of stages of monitoring units which are longitudinally paved and arranged in the sponge facility, and the longitudinal distance of the plurality of stages of monitoring units is in a decreasing mode; each monitoring unit comprises a plurality of paths of fiber grating sensor groups connected in parallel, the distances between adjacent fiber grating sensors in a single branch are equal, and the distance between adjacent branches is greater than the distance between adjacent fiber grating sensors in the single branch. The invention utilizes the optical fiber sensing technology to measure the infiltration rate of rainwater in soil, thereby indirectly reflecting the water accumulation condition in the natural sponge facilities in the current city and making corresponding early warning measures.)

1. A real-time early warning and monitoring platform for accumulated water in a natural sponge facility is characterized by comprising a plurality of stages of monitoring units which are longitudinally paved and arranged in the sponge facility, wherein the longitudinal distance of the plurality of stages of monitoring units is in a decreasing mode;

each monitoring unit comprises a plurality of paths of fiber grating sensor groups connected in parallel, the distances between adjacent fiber grating sensors in a single branch are equal, and the distance between adjacent branches is greater than the distance between adjacent fiber grating sensors in the single branch.

2. The real-time early warning and monitoring platform for waterlogging of natural sponge facilities as claimed in claim 1, wherein there is a certain gap between the outermost fiber grating sensor in each monitoring unit and the edge of the sponge facility.

3. The real-time early warning and monitoring platform for waterlogging of natural sponge facilities as claimed in claim 2, wherein the gap is not less than 75 cm.

4. The real-time early warning and monitoring platform for waterlogging in natural sponge facilities as claimed in claim 1, wherein the interval between two adjacent branches in one monitoring unit is not less than 1.5 m.

5. The real-time early warning and monitoring platform for waterlogging in natural sponge facilities as claimed in claim 1, wherein the distance between adjacent fiber grating sensors in each branch is not less than 1 m.

6. The real-time early warning and monitoring platform for waterlogging in natural sponge facilities as claimed in claim 1, wherein the real-time early warning and monitoring platform is arranged in red and red soil layer.

7. The real-time early warning and monitoring platform for waterlogging in natural sponge facilities as claimed in claim 6, is characterized in that a longitudinal three-stage monitoring unit is provided, and the distance from top to bottom to the first layer of soil covering is respectively 18cm, 30cm and 40 cm.

8. A real-time early warning and monitoring system for accumulated water in a natural sponge facility is characterized by comprising a soil seepage monitoring platform, a central control platform, a comprehensive display platform and an early warning response platform;

the soil seepage monitoring platform is the real-time early warning monitoring platform in any one of claims 1-7; when rainfall occurs in a city, measuring the infiltration rate of rainwater in soil through a multi-stage monitoring unit, and inputting the measured infiltration rate into a computer central control platform;

the computer central control platform is connected with the soil seepage monitoring platform, and acquires rainfall intensity information in a certain area within the duration of current rainfall by using the Internet, and the computer central control platform obtains the current accumulated water information through analysis and processing;

the comprehensive display platform is connected with the computer central control platform, and when the accumulated water is judged to exceed a certain threshold value, early warning information is generated;

the early warning response platform is connected with the comprehensive display platform and carries out early warning according to the received early warning information.

9. A real-time early warning and monitoring method for water accumulation of natural sponge facilities is characterized in that the monitoring method is based on the real-time early warning and monitoring system for water accumulation of natural sponge facilities in claim 8, and specifically comprises the following steps:

the multi-stage monitoring unit measures the infiltration rate of rainwater in the soil, and then inputs the rainwater into the computer central control platform;

the computer central control platform is used as the rainwater limit infiltration rate V before the occurrence of the accumulated water under certain rainfall intensity according to the rainwater infiltration rate when the accumulated water occurs in the current natural sponge facility_IWith this V_IIs a threshold value and is measured with the current rainwater infiltration rate V of the soil infiltration monitoring platform_{Oozing out}Comparing to determine the current water accumulation condition; when V is_{Oozing out}＞V_IWhen the rainwater infiltration rate is higher than the rainstorm intensity, the sponge facility works normally, and the runoff control efficiency is exerted;

when V is_{Oozing out}＝V_IIn time, the infiltration rate of the rainwater is equal to the intensity of the rainstorm, and the sponge facilities normally exert runoff control efficiency;

when V is_{Oozing out}＜V_IDuring the period of rainfall, the infiltration rate is lower than the intensity of rainstorm, the infiltration rate in the soil can not meet the current rainfall intensity, and the sponge facility starts to generate surface accumulated water; and at the moment, the comprehensive display platform generates accumulated water early warning information and carries out early warning through the early warning response platform.

Technical Field

The invention relates to a sponge city technology and an optical fiber sensing technology, in particular to a real-time early warning and monitoring system and method applicable to urban natural sponge facilities.

Background

In the present sponge city construction process, in order to realize inhaling, oozing, net, hold four high functions to the rainwater, improve rainwater recycle in the city, reduce the probability that flood calamity takes place. Various basic sponge facilities such as pervious concrete, ceramic pervious bricks, comprehensive pipe galleries, concave greenbelts, grass planting ditches and the like are widely popularized in the construction process of sponge cities, so that the runoff cutting rate of rainwater is greatly improved. However, in the actual rainfall process, the sponge facilities such as the concave greenbelts and the grass planting ditches, which utilize the natural sponge bodies to absorb and utilize the rainwater, cannot effectively exert the rainwater absorbing capacity of the facilities, so that the water accumulation phenomenon often occurs sometimes, and the rainwater can overflow in severe cases, so that disasters such as road collapse, landslide and debris flow occur, and influence of different degrees is brought to residents.

Disclosure of Invention

The invention provides a real-time early warning and monitoring system for natural sponge facility accumulated water, which aims to realize real-time monitoring and early warning for natural sponge facility accumulated water in cities, timely respond when the natural sponge facility accumulated water phenomenon occurs, reduce surface runoff and relieve urban waterlogging.

The technical scheme adopted by the invention is as follows:

the real-time early warning and monitoring platform for the accumulated water of the natural sponge facility comprises a plurality of stages of monitoring units which are longitudinally laid and arranged in the sponge facility, wherein the longitudinal distance of the plurality of stages of monitoring units is in a decreasing mode;

each monitoring unit comprises a plurality of paths of fiber grating sensor groups connected in parallel, the distances between adjacent fiber grating sensors in a single branch are equal, and the distance between adjacent branches is greater than the distance between adjacent fiber grating sensors in the single branch.

According to the technical scheme, a certain gap is formed between the outermost fiber grating sensor in each monitoring unit and the edge of the sponge facility.

According to the technical scheme, the gap is not less than 75 cm.

According to the technical scheme, the interval between two adjacent branches in one monitoring unit is not less than 1.5 m.

According to the technical scheme, the distance between the adjacent fiber bragg grating sensors in each branch is not less than 1 m.

According to the technical scheme, the real-time early warning and monitoring platform is arranged in the red and red soil layer.

According to the technical scheme, the three-stage longitudinal monitoring unit is specifically arranged, and the distance from the top to the bottom to the first layer of the soil covering is respectively 18cm, 30cm and 40 cm.

The invention also provides a real-time early warning and monitoring system for the accumulated water of the natural sponge facility, which comprises a soil seepage monitoring platform, a central control platform, a comprehensive display platform and an early warning response platform;

the soil seepage monitoring platform is the real-time early warning monitoring platform in any one of claims 1-7; when rainfall occurs in a city, measuring the infiltration rate of rainwater in soil through a multi-stage monitoring unit, and inputting the measured infiltration rate into a computer central control platform;

the computer central control platform is connected with the soil seepage monitoring platform, and acquires rainfall intensity information in a certain area within the duration of current rainfall by using the Internet, and the computer central control platform obtains the current accumulated water information through analysis and processing;

the comprehensive display platform is connected with the computer central control platform, and when the accumulated water is judged to exceed a certain threshold value, early warning information is generated;

the early warning response platform is connected with the comprehensive display platform and carries out early warning according to the received early warning information.

The invention provides a real-time early warning and monitoring method for accumulated water in a natural sponge facility, which is based on the real-time early warning and monitoring system for accumulated water in the natural sponge facility and specifically comprises the following steps:

the multi-stage monitoring unit measures the infiltration rate of rainwater in the soil, and then inputs the rainwater into the computer central control platform;

the computer central control platform is used as the rainwater limit infiltration rate V before the occurrence of the accumulated water under certain rainfall intensity according to the rainwater infiltration rate when the accumulated water occurs in the current natural sponge facility_IWith this V_IIs a threshold value and is measured with the current rainwater infiltration rate V of the soil infiltration monitoring platform_{Oozing out}Comparing to determine the current water accumulation condition; when V is_{Oozing out}＞V_IWhen the rainwater infiltration rate is higher than the rainstorm intensity, the sponge facility works normally, and the runoff control efficiency is exerted;

when V is_{Oozing out}＝V_IWhen it is, rainwater is presentThe infiltration rate of the sponge is equal to the intensity of rainstorm, and the sponge facilities normally exert runoff control efficiency;

when V is_{Oozing out}＜V_IDuring the period of rainfall, the infiltration rate is lower than the intensity of rainstorm, the infiltration rate in the soil can not meet the current rainfall intensity, and the sponge facility starts to generate surface accumulated water; and at the moment, the comprehensive display platform generates accumulated water early warning information and carries out early warning through the early warning response platform.

The invention has the following beneficial effects: the invention utilizes the optical fiber sensing technology to measure the rainwater infiltration rate in the soil, and the multiple parallel branches can be applied and measured in most sponge facility types, thereby being suitable for large-area popularization in sponge areas, reflecting the water accumulation condition in the natural sponge facilities in the current city and being convenient for making corresponding early warning measures. Meanwhile, in the longitudinal multi-stage monitoring of the soil, decision-making personnel can be facilitated to accurately monitor the soil of different levels in the facility in real time, and the rainwater infiltration condition of each layer of soil can be known, so that the integral average rainwater infiltration rate of the structure can be obtained.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a graph of soil layer underwater permeability rate change with time:

FIG. 2 is a schematic structural diagram of a real-time early warning and monitoring system for water accumulation in a natural sponge facility according to an embodiment of the invention;

FIG. 3 is a schematic diagram of laying a real-time early warning monitoring platform according to an embodiment of the invention;

fig. 4 is a diagram of a monitoring system according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In order to realize real-time monitoring and early warning of the natural sponge facility accumulated water in the city, the natural sponge facility accumulated water phenomenon is responded in time, surface runoff is reduced, urban waterlogging is relieved, the rainwater infiltration rate in soil is measured by using an optical fiber sensing technology, so that the accumulated water condition in the natural sponge facility in the current city is indirectly reflected, and corresponding early warning measures are taken.

For natural sponges, the soil layer mainly assumes the function of infiltration and storage of rainwater. The rainwater has three stages in the process of infiltrating into the soil, namely infiltration, infiltration and infiltration stages, wherein in the infiltration stage, the water content in the soil is low, and the infiltrating rainwater is mainly acted by molecular force; in the seepage stage, capillary force and gravity are mainly used, water irregularly moves among pores and gradually fills the pores of the soil until the pores are close to or saturated; and a penetration stage, wherein the content of the rainwater in the soil is saturated, and the rainwater moves downwards under the action of gravity. According to the related data, the rain water permeation rate in the natural sponge body has a certain rule along with the time change, and the rain water permeation rate in the natural sponge facility is continuously reduced along with the continuous increase of the time, and finally approaches to a constant value.

The real-time early warning and monitoring platform for the accumulated water of the natural sponge facility comprises a plurality of stages of monitoring units which are longitudinally paved and arranged in the sponge facility, wherein the longitudinal distance of the plurality of stages of monitoring units is in a decreasing mode; each monitoring unit comprises a plurality of paths of fiber grating sensor groups connected in parallel, the distances between adjacent fiber grating sensors in a single branch are equal, and the distance between adjacent branches is greater than the distance between adjacent fiber grating sensors in the single branch.

Further, a certain gap is reserved between the outermost fiber grating sensor in each monitoring unit and the edge of the sponge facility. In the preferred embodiment of the present invention, the gap is not less than 75 cm.

The real-time early warning monitoring platform can monitor the rainwater infiltration rate of the natural sponge in the sponge city sponge facility in a certain time period under certain rainfall intensity by utilizing the refractive index of a refractive index temperature sensitive element of a measuring point through a monitoring method for the rainwater infiltration rate of the natural sponge in the sponge city sponge facility in the patent application No. CN201810380169.2 and outputting different signals to reflect the temperature principle, the temperature change of a soil layer before and after the water seepage of the natural sponge is monitored, sensors are laid in the surface layer and the natural sponge facility with certain thickness, and the rainwater infiltration rate in the natural sponge facility can be measured in a certain time period according to the physical quantities such as the thickness of the soil layer and the rainwater infiltration time.

For the measurement of the rainwater infiltration rate of a multi-stage sensor, a related mathematical model is established according to the reaction time difference of front and rear temperature sensitive elements and the longitudinal distance of the temperature sensitive elements to obtain the infiltration rate, when the mathematical model is established, a large amount of on-site infiltration monitoring data in each soil layer are combined, the thickness of soil between each stage and the time duration of temperature difference response are subjected to linear fitting, parameters are introduced into the model according to different physicochemical properties (such as water permeability, volume weight and the like) of the soil of each layer to optimize the model, and the R is further improved²Ensure R²Is greater than 0.99. After a mathematical model is established, different rainwater infiltration rates in the soil layers of different levels are obtained independently, and then the soil layers (H) are monitored in combination with each level₁、H₂、H₃、H₄、H₅) Thickness of total soil layer of structure_{General assembly}) And (4) further calculating the rainwater infiltration rate of the local structures of the laying monitoring system. In order to further understand the property change of the soil layer in the rainfall process, a linear fitting mathematical model of the soil layer runoff pollution control rate, the soil layer runoff reduction rate and the infiltration rate is established to evaluate the real-time condition of each stage of soil layer.

The calculation process is as follows: respectively calculating the rainwater penetration rate V of each soil layer by using different mathematical models suitable for each soil layer₁、V₂、V₃、V₄、V₅. On the basis, the rainwater infiltration rate in the whole structure is obtained by the following formula:

in the same region, under the condition that hydrological conditions are similar, the physical and chemical properties of soil are stable, when rainfall occurs, the permeation rate in the soil has a certain relation with the water content, the water content of the soil is continuously increased along with the continuous progress of the rainfall, the permeation rate is reduced, when a certain time is up, the phenomenon of water accumulation on the surface of the soil is often caused, and along with the lapse of time, the permeation rate shows a stable change rule (as shown in figure 1), so that a monitoring means for the phenomenon of water accumulation on the surface of the soil by adopting the permeation rate is firstly proposed.

Under a certain rainfall intensity, the rainwater infiltration rate of the current natural sponge facility when the water is accumulated is measured by using the optical fiber rainwater infiltration monitoring system and is used as the rainwater limit infiltration rate V before the water is accumulated under the certain rainfall intensity_IWith this V_IIs a threshold value and is compared with the current rainwater infiltration rate measured by the optical fiber monitoring system, so as to determine the current ponding condition.

Thus, an early warning system is constructed, and a specific early warning system is as follows, wherein V is set_IThe ultimate infiltration rate of rainwater under the current rainstorm intensity, V_{Oozing out}The current infiltration rate of the rainwater in the soil.

When V is_{Oozing out}＞V_IDuring the period, the infiltration rate of rainwater is higher than the intensity of rainstorm, in the rainfall process at the stage, the soil can rapidly infiltrate the rainwater to prevent the rainwater from forming surface runoff, the sponge facility can work normally, and the runoff control efficiency is exerted;

when V is_{Oozing out}＝V_IDuring the rainfall period, the infiltration rate of the rainwater is equal to the intensity of the rainstorm, the infiltration rate of the soil is equal to the intensity of the rainfall during the rainfall period, the sponge facility can normally exert runoff control efficiency during the rainfall period before the point, and the working efficiency of the sponge facility reaches the design limit at the point;

when V is_{Oozing out}＜V_IAt the moment, the infiltration rate is lower than the intensity of rainstorm, and in the rainfall process at the stage, the infiltration rate in the soil cannot meet the current rainfall intensity, and the sponge facility begins to generate surface accumulated water. And at the moment, early warning of accumulated water in the monitoring area can be sent out.

As shown in fig. 2, the real-time early warning and monitoring of the accumulated water in the natural sponge facility in the embodiment of the invention comprises a soil seepage monitoring platform, a central control platform, a comprehensive display platform and an early warning response platform. The computer central control platform is applied to the soil seepage monitoring platform and the internet platform to comprehensively process the underwater seepage rate data of the rain in the soil and the related current rainfall intensity information, and the comprehensive display platform is connected with the computer central control platform to display the current water accumulation condition of the sponge facility in the city. The early warning response platform is arranged behind the computer central control platform and used for sending out early warning instructions.

When rainfall occurs in a city, monitoring instruments distributed in the soil acquire the infiltration rate of rainwater in the soil and then input the rainwater into a computer central control platform layer, meanwhile, the computer central control platform acquires rainfall intensity information in a certain area within the duration of current rainfall by using the Internet, after the information of the rainfall intensity information and the rainfall intensity information is integrated, the computer central control platform processes the information to obtain corresponding current accumulated water information, the current accumulated water information is displayed on a comprehensive display platform, and when the situation of accumulated water is judged to be deteriorated, certain early warning information is sent out and is input into an early warning response platform for early warning.

In one embodiment of the invention, in the range of taking every 3m × 4m (12 square meters) as a monitoring unit, the optical fiber sensor is laid in a two-way parallel manner, the middle of two branches is spaced by 1.5m, and the distance between the left side and the right side of each branch and the outer edge of a sponge facility is not less than 75 cm; in parallel laying, a single branch is laid once every 1m, and is composed of an upper fiber bragg grating sensor and a lower fiber bragg grating sensor, as shown in fig. 3.

Use red soil layer as an example, when the sensor was laid, in order to make the result of obtaining more accurate, the distance of first order and second level has been injectd during vertically laying, lay the different leading causes of distance because along with the continuous increase of degree of depth in the soil layer, physical and chemical properties such as soil compactness, porosity change, lead to rainwater infiltration rate to change in different degree of depth soil layers, detect the discovery according to basic experiment, south many topcoats red soil infiltration coefficient is 5 x 10 mostly^-2cm/s, and when the depth is increased, the soil permeability coefficient is reduced to 4 multiplied by 10^-2cm/s, and a permeability coefficient of about 3.5X 10 when the depth reaches 40-50cm^-2cm/s. In order to meet the monitoring precision of the sensor, when the first-stage sensor and the second-stage sensor are laid, the thickness of the first-layer soil covering is about 3cm, the infiltration requirement of rainwater for 1 minute is met, and then, in the laying of the second stage, the third stage and the fourth stage, the response of the monitoring system every 5min is metTime, sensors were laid down at depths of 18cm, 30cm, 40cm, respectively.

Depth determination H ═ H_{Infiltration of water}×T

In the non-point source monitoring, because the water permeability rate of surface soil is constant, the temperature sensor is a rod-shaped sensitive element, in the unidirectional series monitoring, the monitoring range before and after the rod shape is tested to be (0.5 +/-0.25 m), because the detection error is larger under different terrains, in order to ensure the precision, the interval of the interval (1.5 +/-0.5 m) is adopted before and after the sensor, and for the measurement of the parallel interval, the rod-shaped sensor can effectively detect to be (0.75 +/-0.5 m), so the arrangement scheme of the interval (1.5 +/-0.5 m) is adopted by each parallel branch line.

Example 1

When the city rains, at 55mm/d rainfall intensity, the image of the water seepage rate of the soil under the rainfall intensity along with the time is shown in figure 3, and the following images are found through certain measurement: when the soil type of the area is sand shale red soil (the soil is acidic, the pH is more than 5.0-5.5, the organic matter content is low, the cation exchange capacity is low, and the total porosity of the soil is 47.2 percent on average), when the soil infiltration rate reaches 0.62cm/min, the natural sponge facility is in a water saturation state between the water accumulation state and the complete water infiltration state, and the rainwater limit infiltration rate V is set in a computer central control platform_I＝0.62cm/min。

At the early stage of rainfall, the soil rainwater infiltration capacity is stronger, can accomplish the infiltration to the rainwater that falls to the natural sponge facility layer of permeating water, V in this stage_{Oozing out}＜V_I(0.62cm/min), no water accumulation is generated at this time, and the natural sponge facility can exert rainwater infiltration efficiency.

As shown in fig. 4, as rainfall progresses, the soil water seepage rate monitored by the soil water seepage monitoring platform continuously decreases, and when V is measured_{Oozing out}＜V_I(0.62cm/min), the red-red soil surface layer in the natural sponge facility can gradually generate water accumulation, the comprehensive display platform is utilized to visually display the early warning condition of the facility, and the on-duty personnel can utilize the computer central control platform to perform water accumulation early warning correspondingly to make corresponding deployment.

Example 2

When the city rains, at the rainfall intensity of 75mm/d, the image of the water seepage rate of the soil under the rainfall intensity along with the time is shown in figure 4, and the following images are found through certain measurement: when the soil type of the area is red soil and the soil infiltration rate reaches 0.69cm/min, the natural sponge facility is in a water saturation state between the water accumulation state and the complete water infiltration state, and the rainwater limit infiltration rate V is set in the computer central control platform_I＝0.69cm/min。

At the early stage of rainfall, the soil rainwater infiltration capacity is stronger, can accomplish the infiltration to the rainwater that falls to the natural sponge facility layer of permeating water, V in this stage_{Oozing out}＜V_I(0.69cm/min), no water accumulation is generated at the moment, and the natural sponge facility can play a role in rainwater infiltration.

The soil water seepage rate monitored by the soil water seepage monitoring platform is continuously reduced along with the rainfall process, and when V is measured_{Oozing out}＜V_I(0.69cm/min), the red-red soil surface layer in the natural sponge facility can gradually generate water accumulation, the early warning condition of the facility is visually displayed by using the comprehensive display platform, and the on-duty personnel can perform water accumulation early warning correspondingly by using the computer central control platform to make corresponding deployment.

Example 3

When the city rains, at 55mm/d rainfall intensity, the image of the water seepage rate of the soil under the rainfall intensity along with the time is shown in figure 3, and the following images are found through certain measurement: when the soil type of the area is brown soil (the soil is thin in texture and high in field water holding capacity which is 25% -30%, the water retention performance is good, most of the surface soil layer is sandy soil or loamy sandy soil, most of the middle part of the section is silty soil), when the soil infiltration rate reaches 0.56cm/min, the natural sponge facility is in a water saturation state between the water accumulation state and the complete water infiltration state, and the rainwater limit infiltration rate V is set in the computer central control platform_I＝0.56cm/min。

At the early stage of rainfall, the soil rainwater infiltration capacity is stronger, can accomplish the infiltration to the rainwater that falls to the natural sponge facility layer of permeating water, V in this stage_{Oozing out}＜V_I(0.56cm/min), no water accumulation is generated at the moment, and the natural sponge facility can play a role in rainwater infiltration.

The soil water seepage rate monitored by the soil water seepage monitoring platform is continuously reduced along with the rainfall process, and when V is measured_{Oozing out}＜V_I(0.56cm/min), the red-red soil surface layer in the natural sponge facility can gradually generate water accumulation, the comprehensive display platform is utilized to visually display the early warning condition of the facility, and the on-duty personnel can utilize the computer central control platform to perform water accumulation early warning correspondingly to make corresponding deployment.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.