JP5131400B1 - Search method of unsteady dust source position of falling dust - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently and accurately search for a dust generation source of falling dust in which a dust generation amount fluctuates unsteadyly in a nuclear power plant or the like.
SOLUTION: First and second generation source search regions γ (i _M , i _t ), γ (having a central axis extending from an evaluation point i _M , i _N to a windward direction of a representative wind direction WD. i _N , i _t ) at the coordinate point p in the evaluation point i _M , i _N , the center axis vertical cross-sectional area S _p1 , S _p2 of the dust source search area for the evaluation point i _M , and the coefficient B ₁ E ₁ and E ₂ are calculated, and it is determined whether or not the ratio of the assumed dust generation amounts E ₁ and E ₂ is within a predetermined range.
[Selection] Figure 6

Description

  The present invention relates to a technique for searching for a dust generation source of falling dust in the atmosphere.

When a nuclear power plant is destroyed due to an accident, it is an important industrial issue in recent years to grasp the behavior of radioactive dust falling from a plurality of radioactive dust generation facilities. Also, dustfall occurs in various industries such as agriculture and forestry. Dust dust generated from the natural world such as sand dunes cannot be ignored. Technology that analyzes which dust source contributes greatly as an effect on the `` measurement value of the amount of dustfall '' at the evaluation point of dustfall when there are many dust sources that can be a source of dustfall Is important in managing these dustfalls and taking countermeasures.
From this point of view, the technology for evaluating the influence of the amount of dust generated at multiple sources from the amount of dustfall measured at the evaluation point, that is, the technology for searching for the main sources of dustfall is patented. It is disclosed in Documents 1-4.

  First, Patent Document 1 discloses the following technique. That is, a model suitable for simulation is selected from input conditions such as atmospheric conditions, meteorological data, and topographic data in the evaluation range of air pollutant diffusion. Further, in order to improve the analysis accuracy, the adjustment input parameter is selected from the measured value of the database unit corresponding to the input condition. Then, the input data is created from the analysis conditions based on the selected model and the selected adjustment input parameter, and simulation is performed. The deviation between the result and the emission source measurement value data is calculated, and the deviation is minimized. Estimate the emission source corresponding to the data.

  Patent Document 2 discloses the following technique. That is, the normal emission amount released from the emission source during the period when the atmospheric chemical concentration measured in advance by the atmospheric observation station does not show an abnormally high concentration, and the atmospheric chemical concentration showed an abnormally high concentration. Obtain abnormal emissions of chemicals released from sources during the period. Then, by obtaining a solution that minimizes the sum of the squares of the emission sources (normal emission amount−normal emission amount), the emission source that causes the abnormally high concentration of the chemical substance in the atmosphere is specified.

  Patent Document 3 discloses the following technique. That is, the amount of scattered dust and the wind direction are measured at a predetermined time pitch at a plurality of arbitrary measurement locations around the plurality of dust generation locations over an appropriate period. Next, an average scattered dust amount for each wind direction is calculated for each measurement location from the obtained scattered dust amount and the wind direction. Next, on a map including a plurality of dust generation locations and a plurality of measurement locations, a plurality of wind direction directions with a large average amount of scattered dust are plotted around each measurement location. Next, the dust generation location where the intersection where the wind direction from each measurement location intersects is located, or the dust generation location on the map that exists in the wind direction when the wind direction from each measurement location is almost the same Is identified as the source of scattered dust.

  Patent Document 4 discloses the following technique. In other words, one or more portable self-supporting multi-sensing units that measure the air pollution status of multiple items are remotely controlled via a wireless or wired network to measure the air pollution status of multiple items, and the measurement Collect and display data.

In addition, when evaluating the concentration of dust falling at the evaluation point from the amount of dust generated at the generation source, a plume type is usually used. In Patent Document 5, a standard plume equation such as the following equation (1) is shown as an atmospheric diffusion model of gas from a point source without adsorption on the ground surface.
C (x, y, z) = (Q _P / 2πσ _y σ _z WS) exp [−y ² / 2σ _y ² ]
X {exp [-(He-z) ² / 2σ _z ² ]
+ Exp [-(He + z) ² / 2σ _z ² ]} (1)

Here, the meanings of the symbols in the formula (1) are as follows. The meanings of these symbols are the same in the following description. The following symbols are all SI unit systems.
x, y, z: three-dimensional orthogonal coordinates of the evaluation point (with the gas generation source as the origin)
x: coordinate value corresponding to the direction in which the plume central axis extends on the horizontal plane y: direction perpendicular to the direction in which the plume central axis extends on the horizontal plane (in the following description, this direction is referred to as “horizontal direction” as necessary. Coordinate value z: vertical coordinate value C: gas concentration [kg / m ³ or m ³ / m ³ ] at the evaluation point (x, y, z)
Q _P : Gas generation amount [kg / s or m ³ / s]
WS: Wind speed [m / s]
He: Height of the gas generation source from the ground surface [m]
σ _y , σ _z : plume diffusion width [m] (standard deviations of gas concentration distribution in the direction perpendicular to the gas flow, respectively in the horizontal direction and in the vertical direction).

Non-Patent Document 1 shows the following equation (2) as a plume equation regarding a gas that is adsorbed on the ground surface and a fine particle (SPM) having a low falling velocity.
C (x, y, z) = (Q _P / 2πσ _y σ _z WS) exp [−y ² / 2σ _y ² ]
× {exp [- (He- z-V s x / WS) 2 / 2σ z 2]
+ Α · exp [− (He + z−V _s x / WS) ² / 2σ _z ² ]} (2)
Here, α in Expression (2) is expressed by Expression (3) below.
α = 1−2 V _d / {V _s + V _d + (WS · He−V _s ) / σ _z · (dσ _z / dx)} (3)
The meanings of the symbols in the formula (3) are as follows. The meanings of these symbols are the same in the following description.
V _d : deposition speed [m / s]
V _s : Falling speed [m / s] (in case of SPM, 0 in case of gas)

Here, σ _y and σ _z are characteristic values for expressing the “plume diffusion width” in the direction perpendicular to the plume center axis, and the density when assuming a Gaussian concentration distribution in the direction perpendicular to the plume center axis. Is the distance between the point where is the standard deviation and the plume central axis.
Also, the plume formula is not limited to that shown in formula (1). For example, Non-Patent Document 3 discloses a plume equation that assumes a double Gaussian density distribution and uses a curve for the plume central axis.
The features common to these plume formulas are: first, the concentration value at a specific concentration evaluation point, the coordinate value of the evaluation point and the source, the generation rate at the source, and the weather conditions such as wind direction and wind speed. It is expressed by an expression and the result is given uniquely. Second, in calculating the concentration, a central axis is assumed, and a “plume” that forms a high-concentration region characterized by “plume diffusion widths” σ _y and σ _z is set around the central axis. Comparing other methods with the plume equation, the numerical analysis method that calculates the concentration value at a specific concentration evaluation point by numerically solving multiple simultaneous physical equations calculates the concentration without assuming the plume. And the calculation result is different from the plume type because it is not always unique. In addition, the multiple regression equation obtained by simply converting the concentration value at the specific concentration evaluation point into the variable value of the coordinate value of the evaluation point and the source, the generation speed at the source, the weather conditions such as wind direction and wind speed, etc. It is not a plume formula because it is not assumed.

  Here, the “term multiplied by α” in Equation (2) means that the gas or SPM is adsorbed above the ground surface by inverting the shape of the vertical distribution of gas or SPM symmetrically on the ground surface. The effect of adsorption on the ground surface of gas and SPM is adjusted by the magnitude of α. In the following description, the “term multiplied by α” in equation (2) is referred to as “ground surface reflection term” as necessary.

  Further, Patent Document 6 discloses the following technique as a technique for measuring the amount of dustfall at an evaluation point in a short cycle of about 10 minutes. That is, using a funnel-shaped particle sampling port opened upward, an air flow channel circulating in the measuring device, and an inertia classifier provided in the middle of the air flow channel, coarse particles and fine particles are continuously separated. The mass is measured. Then, the transition of the falling speed of the falling dust in the atmosphere is calculated from the measured value of the mass of the coarse particles.

However, the above-described prior art has the following problems.
In other words, the first problem is that the target for searching for the source is not dustfall.
For example, in the techniques of Patent Documents 1, 2, 3, and 4, the target for searching for the generation source is gas. In the technique of Patent Document 3, the SPM is only included in the search target for the generation source. SPM is a much smaller particle compared to falling dust (by definition, SPM is a particle having a diameter of 10 μm or less), and its diffusion behavior in the atmosphere is substantial except that it causes minute particle sedimentation. It is equivalent to the behavior of gas.

On the other hand, the falling dust is a dust particle much larger than SPM (a particle having a diameter of about 10 μm or more), and its falling speed is extremely high. For this reason, the behavior of the dust dispersion in the atmosphere is greatly influenced by the particle falling speed. Therefore, the diffusion behavior of falling dust is greatly different from that of gas.
In addition, the amount of dustfall that is observed and managed here is the amount of dustfall deposition on the ground surface. In the techniques of Patent Documents 1 to 4, the gas and SPM concentrations at the evaluation point are the objects of observation and management. For this reason, it is impossible to directly know the deposition rate of gas and SPM on the ground surface. Indeed, in the formula (2) described above, since the deposition velocity V _d is described, if it is possible to provide a deposition rate V _d precisely, the gas and SPM concentration on evaluation point on the ground surface It is possible to convert the amount of deposition.

However, as described in Non-Patent Document 1, the SPM deposition speed V _d varies greatly due to the influence of the ground surface condition and atmospheric turbulence. Further, a method for generally giving the gas deposition rate V _d has not been developed. Accordingly, it is extremely difficult to accurately give the value of the deposition velocity V _d , and it is difficult to at least quantitatively target the dust falling with the techniques of Patent Documents 1 to 4.

As a second problem, there is no conventional method for searching for a dust generation source for falling dust. In the conventional generation source search method, as represented by Patent Document 3, the search for the generation source in the horizontal plane (the ground surface) is assumed. For this reason, in the conventional source search method, it is difficult to three-dimensionally handle a “dust generation source” that has a high particle fall velocity V _s and has a problem of the amount of deposition on the ground surface. It is. In particular, in the case of the method of extending the search line of the generation source from the evaluation point in the windward direction as shown in Patent Document 3, the ground surface reflection term (α · exp [− (He + z−V _s ) in Expression (2) is used. x / WS) ² / 2σ _z ² ]) is difficult to quantitatively and generally handle, so an effective method for associating source search lines with plume equations has been proposed. Absent.

As a third problem, in the above-described conventional technology, it is essential that a procedure for preliminarily assuming the position of the generation source and the approximate generation amount thereof is essential when searching for the generation source.
For example, in the techniques of Patent Documents 1 and 2, first, regarding all the generation sources and all the evaluation points assumed in advance, the relationship between the generation amount at an arbitrary generation source and the concentration at an arbitrary evaluation point, Predict as a function of weather conditions such as the plume mentioned above. Then, the measured value of the concentration in all evaluation points, such that the difference between the predicted value of the density is minimum, adjusted by optimization method parameter (sigma _y and Q _P, etc.) of the function. Therefore, at least the positions of all the sources need to be given in advance. In order to ensure the validity of the calculation process of the optimization method, it is generally desirable to give the approximate generation amount at each generation source as an initial condition in advance. This is because, in an optimization problem, when an initial condition that is extremely dissociated from the actual situation is given, the solution may converge to a local stable point that is significantly different from the actual situation.

FIG. 7 is a diagram schematically showing a dust generation source search method in the conventional method (Patent Document 3).
In the technique of Patent Document 3, as shown in FIG. 7, a plurality of dust (SPM) generation points a, b, c, d, e, etc. are assumed in advance, and a plurality of surrounding evaluation points i ₁ , The concentration of SPM at i ₂ , i _3, etc. is measured over a long period of time, and within this period, the average SPM concentration 1 for each wind direction at each evaluation point (the polygon surrounding the evaluation points i ₁ , i ₂ , i ₃₎ And the source search lines 2, 3, 3 in the horizontal plane (the ground surface) from the evaluation points i ₁ , i ₂ , i ₃ , respectively, in the windward direction of the wind direction where the average value of the SPM becomes the largest. Among the intersections 6, 7, and 8 of these source search lines that intersect each other, a point that matches any of the dust (SPM) generation points a, b, c, d, and e, In addition, it is determined that the generation location of the generation amount of dust (SPM) is large.

Moreover, in the technique of patent document 4, it is a premise that a measuring machine is provided in the vicinity of the assumed generation source. Thus, the source must be known in advance.
However, when there are a large number of sources, it is actually difficult to grasp all the positions of these sources and the approximate amount of generation in advance. It is not suitable because it requires it. Therefore, the techniques of Patent Documents 1 to 4 have a problem that the number of generation sources can be effectively applied only in an environment where the number of generation sources is extremely small or the generation amount of generation sources can be grasped sufficiently accurately. is there.

As a fourth problem, the generation source targeted in the prior art is basically a steady generation source in which the generation amount does not vary with time, or the generation amount is slightly close to the time average value. It is a quasi-stationary dust generation source that only fluctuates.
For example, in Patent Documents 1 and 2, an optimization method is applied. For this reason, in general, the number of evaluation points must be set larger than the number of parameters that can be adjusted in a function such as an applied plume equation. This is because, if the number of adjustable parameters is substantially larger than the number of evaluation points, the obtained solution is generally not uniquely determined, and the method fails.

When there are a large number of sources, the number of evaluation points is often set to be smaller than the number of sources from the viewpoint of economy. Even in this case, (unless the words that can adjust a generation quantity Q _P parameter) if only the origin to the constant source, by using the measured values at the evaluation points in a number of different times Measured values more than the number of sources can be ensured, and optimization techniques can be applied. The resulting contrast, the amount Q _P fluctuates unsteady large, in applying the technique of Patent Documents 1 and 2 for the non-stationary source, the generation amount Q _P, forced to an adjustable parameter Absent. For this reason, when a large number of generation sources are to be searched, it is necessary to provide a very large number of evaluation points exceeding the number of generation sources, which is not practical from the viewpoint of economy.

In the technique of Patent Document 3, the source is searched by averaging the concentration data of SPM at discrete evaluation points collected within a period of two months or more. Therefore, the generation source is limited to a stationary generation source.
Moreover, in the technique of patent document 4, since an evaluation point is arrange | positioned in the vicinity of the assumed generation source, an unsteady generation source can be searched in principle. However, this technology discloses a method for determining which of a plurality of sources is an excellent source when gases from a plurality of sources arrive at a specific evaluation point at the same time. Neither is it disclosed that an evaluation point is installed in the vicinity of all possible sources. Therefore, it is possible to search for an unsteady dust generation source with this technique only when the distance between the generation sources is so far as not to affect each other. That is, this technique can be applied only when the generation source and the evaluation point are substantially associated one to one.
However, an actual generation source generally has a large generation amount and fluctuates with time. Therefore, the conventional technology that targets only a stationary source or a source that has a one-to-one correspondence between the source and the evaluation point has a problem that it cannot be sufficiently applied to an actual source search.

  In addition, when the dust is radioactive, the radiation dose such as α rays, β rays, or γ rays of the dust can be measured by the methods disclosed in Patent Documents 7 to 9.

JP 2003-255055 A Japanese Patent Laid-Open No. 2005-292041 JP 2004-170112 A JP 2003-281671 A JP 2007-122365 A JP 2008-224332 A Japanese Patent Laid-Open No. 8-327741 JP-A-7-35900 JP 2009-63510 A

Airborne particulate matter countermeasures study group (supervised by the Environmental Protection Agency, Air Quality Control Bureau, Air Regulation Division): Airborne particulate matter contamination prediction manual, Toyokan Publishing, 1997 Okamoto Junichi: Atmospheric environment prediction lecture, Gyosei, 2001

  The present invention has been made in view of the above circumstances, and a dust generation source for falling dust in which the amount of dust generation (the generation speed of falling dust in the dust generation source) fluctuates non-steadily is efficiently and accurately determined. Aim to explore.

In order to solve the above-mentioned problems, the following solutions have been invented as a result of the inventor's research.
The first invention is a time period Delta] t _d each of i _t-th time _{T d} (i _t), at two or more dustfall evaluation point different time _{T d} (i _t -1) from time T _d ( a dust amount setting step of setting an average measure of the dustfall amount M in the _{i t) T d (i t} ) period is a period until, in each vicinity of the dustfall evaluation point, the time period based on the continuously measured wind direction in a short time period Delta] t _WINT than Delta] t _d, the _{T d} (i _t) and the representative wind deriving step of deriving the representative wind direction WD (i _t) in the period, the dustfall in each vicinity of the evaluation point based on the continuously measured wind direction at the time period Delta] t _d shorter period Delta] t _WINT than, the _{T d} (i _t) representative wind speed WS in period (i _t) a representative wind speed derivation step of deriving, the dustfall evaluated the _{T d} (i _t) period Based on the measured value of the drop rate of the collected dustfall in point, a representative falling speed deriving step of deriving a representative falling velocity V _s of the dustfall, two or more of said successive times T _d (i _t ) a time for each time period Delta] t _g containing is the evaluation period of the k-th time in the case of a t _g (k), from the time t _g (k-1) to time t _g (k) any of the contained in t _g (k) the period _{T d} (i _t) drops in the period dust search area γ (i, i _t) as two different said dustfall evaluation point i _M, a i _N a starting point to each other , Having a central axis extending in the windward direction of the representative wind direction WD, and providing a falling dust generation source search area width around the central axis, and extending vertically from the central axis to the falling dust generation source search area width. the first to the range of distances between regions, the second dustfall generation source search area gamma (i _{M i t), γ (i N} , i t) and dustfall generation source search area setting step of setting a, for the dustfall evaluation point i, t _g (k) the time of maximum dustfall amount M in the period and _{T d} (i _t) dustfall amount M _max (i), and i _max (i) is i _t at the time _{T d} (i _t), representative wind direction and representative of the time _{T d} (i _t) and maximum dustfall information deriving step of deriving the WD _max and WS _max is the wind speed, the first, second dustfall generation source search area _{γ (i M, i max)} , γ (i N, i t) A distance calculating step of calculating distances L _d (i _M ) and L _d (i _N ) between the coordinate point p in both of the two and the two dustfall evaluation points i _M and i _N ; The first and second dustfall generation source search areas on the vertical plane of the central axis of the first and second dustfall generation source search area including the coordinate point p It is the cross-sectional area of the dust source search area center axis perpendicular cross-sectional area S _p1, the S _p2, and the cross-sectional area calculation step of calculating respectively using the dustfall generation source search area width, the dust source search area center axis For all combinations of the dust generation amount calculating step for calculating the assumed dust generation amounts E ₁ and E ₂ proportional to the vertical cross-sectional areas S _p1 and S _p2 and all the falling dust generation source search areas including the coordinate point p On the other hand, if the ratio of any one of the assumed dust generation amounts E ₁ and E ₂ calculated in the dust generation amount calculation step is all within a predetermined upper and lower threshold value range, the coordinate point p is set to t _g (k) _{One of the} assumed dust generation amounts E ₁ calculated in the dust generation amount calculation step by determining that it is a main non-stationary dust generation source having a time scale equal to or greater than the time period Δt _{g in the} period. , E _{2 if} the ratio is outside the predetermined upper and lower threshold values, the coordinate point p is set to t _g (K) When it is determined that it is not a main unsteady dust generation source having a time scale equal to or greater than the time period Δt _g in the period, and the coordinate point p is not included in any of the falling dust generation source search regions Does not determine the non-steady dust generation source of the dustfall at the coordinate point p, and the dustfall source search area width is the plume-type dustfall source in the plume type. It is a plume diffusion width calculated at the distance on the plume center axis with the search region central axis as the plume central axis, and is a method for searching the unsteady dust generation source position of the falling dust.
According to a second aspect of the present invention, the descending soot generation source search region central axis has a horizontal component of the wind direction of the wind direction and a value V _s / the value obtained by dividing the representative falling speed V _s of the falling dust by the representative wind speed WS. A horizontal direction having WS as a vertical gradient and calculated as the falling dust source search area width in the plume formula at the distance on the plume center axis with the lower dust generation source search area center axis as the plume central axis The plume diffusion width σ _y and the plume diffusion width σ _z in the vertical direction are used as the horizontal component and the vertical component, respectively, and the method for searching the unsteady dust generation source position of the falling dust according to the first invention is provided. .
The third invention is the plume diffusion widths σ _y and σ _z , the distance x from the source on the plume central axis, the dust generation amount Q _P , the representative speed WS, the constant B, and the plume diffusion width. Using the plume range defined using σ _y and σ _z , the following equations (A) and (B) expressing the dust concentration C (x) at a distance x from the source on the plume central axis: ) Is used as the plume type according to the first or second aspect of the present invention.
C (x) = B (Q _P / 2πσ _y σ _z WS) (within the plume range) (A)
C (x) = 0 (outside the plume range) (B)
According to a fourth aspect of the present invention, a cross section of a plume in a direction perpendicular to the plume central axis is an ellipse having a longer axis as a major axis and a shorter axis as a minor axis of the longer one of the plume diffusion widths σ _y and σ _z. The method for searching for the unsteady dust generation source position of the falling dust according to the third aspect of the invention, wherein the plume range is calculated with the inside of the ellipse within the plume range as the shape.
According to a fifth aspect of the present invention, there is provided a dust type classification step of measuring the radiation dose of the dust falling sample collected at the evaluation point during the period T _d (i _t ) and classifying the dust falling for each dust type based on the intensity thereof. And the amount of dust falling in the portion corresponding to any one of the dust species classified in the dust type classification step is set as the amount of dust falling M. The method for searching for the unsteady dust generation source of the falling dust according to any one of the first to fourth inventions.

  According to the present invention, it is possible to efficiently and accurately search for dust generation sources of falling dust in which the amount of dust generation varies unsteadily by measuring the amount of falling dust at a small number of evaluation points.

It is a figure which shows an example of the plume projected in the horizontal surface. It is a figure which shows an example of the plume projected on the vertical plane. It is a flowchart explaining an example of a process of a dust generation source search apparatus. It is a figure which shows an example of a dust generation source search area | region. It is a figure explaining an example of the method of searching for a dust generation source. It is a figure explaining an example of the method of setting a dust generation source search area | region in directions other than the wind direction which shows a density | concentration maximum value. It is a figure explaining the conventional method which searches a dust generation source.

(Features of Embodiments of the Present Invention)
First, features of the embodiment of the present invention will be described.
The first feature of the embodiment of the present invention is that a dust generation source for falling dust can be searched by directly measuring the falling dust at the falling dust evaluation point.

The second feature of the present invention is that, in searching for the dust source of the falling dust, the dust source search region that extends in the windward direction from the falling dust evaluation point is correlated with the plume expression, thereby generating a dust source candidate. It is a point which can acquire the information of the amount of dust generation in.
Specifically, as described above, in the prior art, it is difficult to handle the ground surface reflection term (α · exp [− (He + z−V _s x / WS) ² / 2σ _z ² ]) in the formula (2). Met. For this reason, it was considered difficult to correlate the dust source search line that extends from the falling dust evaluation point in the windward direction with the plume type. However, as a result of investigations by the present inventors, it has been found that this ground surface reflection term becomes a problem because the prior art mainly targets gas and SPM. In the case of falling dust, since the falling speed of the particles is high, the deposition speed V _d ≈the falling speed V _s . Therefore, the influence of reflection on the ground surface is small, and can be regarded as α = 0. Therefore, the atmospheric diffusion formula (plume formula) for the falling dust is expressed by the following formula (4) in which α = 0 is substituted into formula (2).
C (x, y, z) = (Q _P / 2πσ _y σ _z WS) exp [−y ² / 2σ _y ² ]
× exp [- (He-z -V s x / WS) 2 / 2σ z 2] ··· (4)

Here, when coordinate transformation is performed according to the following equation (5), equation (4) becomes the following equation (6).
_{Z = z + V s x /} WS-He ··· (5)
C (x, y, Z) = (Q _P / 2πσ _y σ _z WS)
Xexp [−y ² / 2σ _y ² ] exp [−Z ² / 2σ _z ² ] (6)
Here, the coordinate conversion from z to Z according to the equation (5) is performed with tan ⁻¹ (V _s (particle fall velocity) / WS (wind velocity)) in the leeward direction with the generation source (dust generation source) as the origin. This corresponds to setting the central axis of the dust plume in the vertical plane at the depression angle and defining the concentration with this central axis as the Z axis.

The diffusion widths σ _y and σ _z are respectively the concentration distributions in the y direction and the z direction (usually, V _s << WS, and under the condition of V _s << WS, the z direction is almost equal to the Z direction). Standard deviation. In many cases, if there is no influence of reflection on the ground surface, the density distribution in the y direction and the z direction can be regarded as a normal distribution. At this time, the density value at y = σ _y and Z = σ _z is 60% of the maximum density value, whereas the density value at y = 2σ _y and Z = 2σ _z is 13% of the maximum density value. Not too much. That is, the concentration decreases rapidly in the region where y> σ _y and Z> σ _z . Therefore, in the embodiment of the present invention, the following equations (7a) and (7b) are assumed as plume equations.
C (x) = B (Q _P / 2πσ _y σ _z WS) (within the plume range) (7a)
C (x) = 0 (outside the plume range) (7b)

Here, the meanings of the symbols in the formula (7a) are as follows.
B: Proportional constant In this method, since the equation (7a) is concerned only with the relative value, the proportionality constant B may be given an arbitrary value (for example, 1).
In addition, the plume range refers to a region on the central axis side from the position where the density when the Gaussian distribution is assumed in the density distribution in the plume vertical direction as shown in Expression (4), where the density shows the value of the standard deviation of the density distribution. . Or, more simply, an ellipse having a major axis that is twice as long as σ _y or σ _z and a minor axis that is twice as long as the shorter axis may be a plume cross-sectional shape, and the inside of this ellipse may be within the plume range. . Furthermore, it is good also as the range of the following formula | equation (8) more simply. On the other hand, “outside the plume range” means an area other than the plume range.
σ _y ≧ y ≧ −σ _y and σ _z ≧ Z ≧ −σ _z (8)
Here, σ _y and σ _z are functions of the distance L ₀ from the dust generation source and the period Δt _d (σ _y [L ₀ , Δt _d ], σ _z [L ₀ , Δt _d ]). σ _y and σ _z are those according to Pasquill-Gifford described in Non-Patent Document 1 as numerical values or chart values obtained by fixing the period Δt _d (this is a reference period). and the like used by Briggs, determined by correcting the influence of the periodic Delta] t _d by empirical formula. As shown in Non-Patent Document 2, a method for correcting the influence of the period Δt _d by the empirical formula is obtained by adding ([actually used Δt _d ] / [reference pure time Δt _d ]) to the plume diffusion width σ _y . Multiply by ^P.

If the soot type and soot particle size are given, the particle falling speed V _s is determined as the terminal speed, so the falling dust amount M (x) is the following value obtained by multiplying the concentration C (x) by the particle falling speed V _s It can be expressed by Expression (9a) and Expression (9b).
M (x) = V _s B (Q _P / 2πσ _y σ _z WS) (within the plume range) (9a)
M (x) = 0 (outside the plume range) (9b)

In the equation (9a), under a constant wind speed condition, the local dust fall amount M (x) within the plume range is determined only by the dust generation amount Q _P and the plume diffusion widths σ _y and σ _z . Further, the values of the plume diffusion widths σ _y and σ _z can be expressed as a function of x and weather conditions, for example, by the Pasquill-Gifford equation described in Non-Patent Document 1. Therefore, under certain dust source conditions and certain weather conditions, express the amount of dust fall M (x) at a specific dust fall evaluation point only by the distance x from the particular dust source. Can do.
Next, the range of the dust generation source at a specific dustfall evaluation point will be considered using Equation (9).
FIG. 1 shows two dust generations existing at a position of x ′ = L ₀ on a global coordinate system x ′, y ′ (ground surface) in a horizontal plane with a specific falling dust evaluation point i _M as an origin O. from a source i _o1, i _o2, dustfall evaluation point i _M and plume alpha emitted on the same horizontal plane (i _o1), is a view obtained by projecting the α (i _o2). At this time, the wind direction WD is the positive direction of x ′. The positions of the plumes α (i _o1 ) and α (i _o2 ) are such that, at x ′ = 0, the respective central axes 10a and 10b coincide with the ground surface, and the horizontal ends of the plumes (the plumes α ( _io1) ) in y as positive end of the 'negative end of the plume alpha (i _o2) in y') passes through the origin O, plume _{α (i o1), α (} i o2) is arranged Yes. The plume alpha (i _o1), the arrangement of the alpha (i _o2) is, from x = set to L ₀ has been dust source i _o1, i _o2, plume _{α (i o1), α (} i o2) is lowered This is the limit position where the dust evaluation point i _M can be reached. That is, the position of the dust generation source i _o1 is the limit position on the plus side of y ′, and the position of the dust generation source i _o2 is the limit position on the minus side of y ′.

The diffusion width σ _y of the plumes α (i _o1 ) and α (i _o2 ) at x ′ = 0 is σ _y (L ₀ ). Therefore, the half width of the distance between the dust generation sources i _o1 and i _o2 at x ′ = L ₀ is σ _y (L ₀ ), that is, x ′ = 0 of the plumes α (i _o1 ) and α (i _o2 ). This corresponds to the diffusion width σ _y at. Here, when estimating the position of the dust source i _o1, i _o2 when dustfall in dustfall evaluation point i _M is measured, in the horizontal plane, there may be Hatsuchirigen i _o1, i _o2 range is the origin O, line passing through the point of Hatsuchirigen i _o1, and, the area between the line passing through the point of origin O and dust source _{i o2 γ (i M, i} t) ( (Areas shown with diagonal lines). This region γ (i _M , i _t ) is the dust source search range.

By the way, the value of x ′ = L ₀ for arranging the dust generation sources i _o1 and i _o2 is arbitrary. Therefore, the half width of the range in the y ′ direction of the dust generation sources i _o1 and i _o2 that can reach the dustfall evaluation point i _M at an arbitrary position x ′ is always σ _y (x ′). That is, the half width in the y ′ direction of the dust generation source search range γ (i _M , i _t ) has the same shape as σ _y on the same horizontal plane as the dust generation source in the plume formula of Equation (6), for example. . Therefore, dust source search area γ (i _M, i _t) in a horizontal plane, on the central shaft 11 extending from the dustfall evaluation point i _M upwind direction of the representative wind from dustfall evaluation point i _M It can be set by the search area width expressed by a function of only the distance.

FIG. 2 shows two dust generation sources i _o3 existing at a position of x ′ = L ₀ on the entire coordinate system x ′, z in the vertical plane with the specific falling dust evaluation point i _M as the origin O. from i _o4, dustfall evaluation point i _M the same vertical plane on the emitted plume α (i _o3), a diagram obtained by projecting the α (i _o4).
Basically, the dust generation source search region γ (i _M , i _t ) is set by the same method as described with reference to FIG. At this time, the width of the dust generation source search region γ (i _M , i _t ) is represented by the diffusion width σ _z (x ′).
Since the falling dust falls, the central axes 10a and 10b of the plumes α (i _o3 ) and α (i _o4 ) and the central axis 11 of the dust source search region γ (i _M , i _t ) in the vertical section are , Θ (= tan ⁻¹ (V _s / WS)). Therefore, among the windward direction point of dustfall evaluation point i _M, the dustfall from Hatsuchirigen i _o3, i _o4 until dustfall evaluation point i _M can reach, from the dustfall evaluation point i _M It will be restricted to what generate | occur | produced in the one part area | region of the area | region extended in the upwind direction. In this way, in the dust source search method that extends the source search region γ (i _M , i _t ) from the dust fall evaluation point i _M in the windward direction, the range of the distance in the windward direction is limited. Is an idea that did not exist in the conventional method, and this method is advantageous over the conventional method in that the dust generation source search region γ (i _M , i _t ) can be limited.

The simple and quantitative expression of the dust generation source search range γ (i _M , i _t ), which is a modification of the plume formula for the amount of dust fall, is the plume formula based on the conventional gas and SPM. This was not possible, and was made possible for the first time by a series of insights that the present inventors made after paying attention to the fact that the falling speed V _s of the falling dust is relatively high.
In addition, this invention is not limited to using the plume type | formula of Formula (9). For example, when precise measurement is performed in advance to accurately represent the influence of the ground surface reflection term, the term σ _{z in} equation (9) is appropriately set based on the plume equation with the ground surface reflection term remaining. Correction may be added.

  The third feature of the embodiment of the present invention is that it is not always necessary to assume a dust generation source and a dust generation amount in advance. Since an actual dust source often does not know all of its position and dust generation amount in advance, the method of the embodiment of the present invention is advantageous in that it can search for a dust source in accordance with reality. is there.

  A fourth feature of the embodiment of the present invention is that an unsteady dust generation source can be specified. In the method of the embodiment of the present invention, the main period in the time zone is acquired every acquisition period of the measurement value of the amount of dustfall or every time of several consecutive periods of the acquisition period of the measurement value of the amount of dustfall. The source of dust generation can be specified. Therefore, this can be grasped if it is an unsteady dust generation source that fluctuates on a time scale that is equal to or more than several cycles of the acquisition period of the measured value of the amount of dustfall. In addition, the number of falling dust evaluation points necessary for identifying the unsteady dust generation source may be sufficiently smaller than the number of potential dust generation sources.

  The fifth feature of the embodiment of the present invention is that the unsteady dust generation source of radioactive fallen dust is classified as radioactive fallen dust by classifying the fallen dust collected at the evaluation point into radioactive fallen dust or non-radiative fallen dust. It is a point that can be specified by using the falling dust measurement data in the distance without approaching.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, the duplicate description is abbreviate | omitted by attaching | subjecting the same code | symbol.
(First embodiment)
First, a first embodiment of the present invention will be described.
The falling dust amount measuring means (device) measures the falling dust amount (the mass of the falling dust) for each time period Δt _d (hereinafter, “time period” is abbreviated as “period” as necessary). And time T _d which is the output of the measured value of the dustfall amount (i _t). Time _{T d} (i _t -1) from the time _{T d} (i _t) until the time (period) is defined as _{"T d} (i _t) period". i _t is an integer that increases by 1 with the time when the measurement of dustfall started being set to 0. Further, a time constituted by n _t consecutive “T _d (i _t ) periods” is defined as “t _g (k) periods”, where n _t is a natural number of 2 or more. Here, the "t _g (k) period" time the time of the start point of the t _g (k-1), the i _t at this time is 0. And "t _g (k) period" of the end-point of time the time t _g (k), the i _t at this time is n _t. k is an integer that increases by 1 with the time when the measurement of dustfall started being set to 0. In the present embodiment, the source of the falling dust in each “t _g (k) period” is specified, and the time scale (that is, the dust generation duration time) of the period Δt _g (= _nt · Δt _d ) or more. ) Is a search target.

The period Delta] t _g, for example, can be adopted 6 cycles of the periodic Delta] t _d (time period Delta] t _d is 10 minutes, the period Delta] t _g is 1 hour). Dust source can be identified in the present embodiment is a non-stationary dust source scale is more periodic Delta] t _g time. Therefore, setting the period Δt _g to be extremely long is not preferable because the number of unsteady dust generation sources that can be specified decreases. In general, weather conditions differ greatly between daytime and nighttime. For this reason, since many unsteady dust generation sources show a time scale of half a day or less, the period Δt _g is preferably 12 hours or less. Of course, this is not the case when the time scale of the unsteady dust generation source is previously known to be 12 hours or more.

  Further, in a three-dimensional region where the search for the dust generation source can be performed, an orthogonal coordinate system of x, y, z is set, and nx, ny, nz coordinate components are provided on each coordinate axis, The three-dimensional space is represented by nx × ny × nz coordinate points p. Here, the coordinate point p represents a coordinate point whose coordinate axis components are the ixth, iyth, and izth, respectively. The position of each coordinate point is expressed as a position vector from the origin O as Sc (ix, iy, iz) using the order ix, iy, iz of the coordinate components on each coordinate axis. At each coordinate point p, one of three modes of “dust generation source”, “not a dust generation source”, and “undecided” is set as a dust generation source determination mode.

With reference to the flowchart of FIG. 3, an example of processing of the dust source search device (dust source search processing) when searching for the dust source will be described. The dust generation source search device is realized by using, for example, an information processing device (for example, a commercially available personal computer (PC)) provided with an arithmetic device such as a CPU, a memory, an HDD, and various interfaces. For example, the flowchart of FIG. 3 is translated into a computer program that can be executed using a programming language such as C language and stored in advance in an HDD or the like. At the time of execution of the dust generation source search process in the information processing apparatus, the executable computer program stored in the HDD or the like is read and activated by an arithmetic device such as a CPU, and based on a command of the executable computer program The calculation is realized by sequentially executing the calculation by a calculation device such as a CPU. The start timing of the dust generation source search process may be such that the executable computer program is started manually or may be automatically started periodically. As described above, the dust source search device of the present embodiment searches for a dust source of falling dust in the “t _g (k) period” at a certain time.

In the dust source search device, necessary input information such as position information such as the falling dust evaluation point / coordinate point, measured values such as the amount of falling dust, wind direction, wind speed, and analysis values related to the dust type are connected to the information processing device. Using a keyboard, console screen, or the like, it is possible to input manually in advance. The input information that has been input is stored in an HDD or the like, and is appropriately read out as the generation source search process proceeds.
In the dust generation source search apparatus, the unsteady dust generation source determination result for the calculated specific coordinate point and the calculation result such as the dust generation amount can be stored in the HDD or the like and displayed on the console screen or the like.
It should be noted that there is no problem if a part or all of the processing of the dust generation source search apparatus is replaced with other means such as manual calculation.

First, the first step will be described.
In step S201, the dust source search device initializes the dust source determination mode to “undecided” at all coordinate points p.
Next, in step S202, the dust generation source search device determines the positions of all the falling dust evaluation points i (where n _M ≧ i ≧ 1) within the horizontal plane (for example, the ground altitude of 1.5 m) in the coordinate system. It is calculated as a position vector P (i) indicating the position from the origin.
Next, in step S203, dust source searching apparatus, a "representative wind speed WD (i _t) in all of the" _{T d} (i _t) period "contained in the" t _g (k) period ", the representative wind WS and (i _t), dustfall amount M (i, i _t) at all dustfall evaluation points and is representative falling velocity V _s (i, i _t) dustfall "setting (input). In this embodiment, for example, in this step S202, a dust amount setting process, a representative wind direction derivation process, a representative wind speed derivation process, and a representative fall speed derivation process are executed.
Here, the dustfall amount M (i, i _t), for example, by using a continuous dustfall meter described in Patent Document 6, a period Delta] t _d, for example, can be measured as 10 minutes. For example, the wind direction and the wind speed can be set to values measured by using a commercially available propeller type wind direction anemometer with a period Δt _wint (for example, a period of 1 second) shorter than the period Δt _d . The spatial resolution of the wind direction is, for example, 1 ° intervals. Representative wind direction WD (i _t), representative wind speed WS (i _t) may be, for example, using the average value of "wind direction measurements and speed measurements" in the corresponding _{"T d} (i _t) period". In addition, “the vicinity of the falling dust evaluation point” may be a range in which the wind direction / velocity has a high correlation with the wind direction / wind speed over the falling dust evaluation point, for example, a horizontal distance within 1 km from the falling dust evaluation point. can do. In areas where the terrain is monotonous and the wind direction / velocity distribution is small, the horizontal distance may be longer. Also, the height of the wind direction / velocity measurement point can be 10 m from the ground surface, which is the measurement height recommended by the Japan Meteorological Agency. If the assumed height of the dust generation source is sufficiently higher than 10 m, the height between the ground surface and the height of the dust generation source may be set as the measurement point height.

Further, by using the "t _g (k) period" all included in the _{"T d} (i _t) period" in dustfall samples collected in the evaluation point, and measuring the average falling speed, which respectively it can be the used as _{"T d} (i _t) period" representative falling velocity V _s of the corresponding dustfall (i _t). Alternatively, in the case Sanpurigu interval dustfall trapping by the constraints of such measuring devices such as greater than _{T d} (i _t), for example, the "t _g (k) period 'drop the whole dust trapped in the dustfall sample and then, the average falling speed, "t _g (k) period" all included in the _{"T d} (i _t) period" common representative falling velocity _{V s (= V s (i} t) = constant). Examples of the method for measuring the falling speed of the falling dust sample include the following methods. In other words, the falling dust sample is discharged from above the closed container, the time for each falling dust particle to reach the bottom of the container is measured, and the falling distance is divided by the falling time, whereby the falling dust representative drop speed V _s Can be requested. In order to detect the arrival of individual dust particles at the bottom of the container, a sheet-like laser beam is continuously irradiated in the horizontal direction at the bottom of the container, and the dust falls when the dust passes through the laser beam. A method such as detecting scattered light with a photodetector can be employed.

As a method of calculating the representative falling speed V _s from the falling speed of each falling dust particle, the falling time corresponding to the time when 50% of the falling dust particles reach the bottom of the container, It can be adopted as the falling speed of the falling dust particles related to the representative falling speed V _s of the falling dust particles. Alternatively, when the approximate density and shape of the falling dust are known in advance, the representative falling speed V _s of the falling dust particles can be calculated simply by measuring the particle size distribution of the falling dust sample. it can. As a method of calculating the representative falling velocity V _s of the falling dust particles from the particle size of the falling dust, for example, the following equation (10) of the Stokes end velocity can be used.
_{V s = {4gD p (ρ} p -ρ f) / 3ρ f C R} 1/2 ··· (10)
Here, the meanings of the symbols in the formula (10) are as follows (the units are all SI units).
g: Gravity acceleration [m / s ² ]
D _p : particle size [m]
ρ _P , ρ _f : density of particles and fluid [kg / m ³ ]
C _R : Resistance coefficient [−] (various numerical tables are disclosed depending on the particle shape)

Next, in step S204, dust source searching apparatus, "dust source search area for each dustfall evaluation point gamma (i, i _t)" in all the dustfall evaluation point i, and "t _g (k) It sets in all of the time T _d in the period "(i _t). In this embodiment, for example, in step S204, a dustfall generation source search region setting step is executed.
Figure 4 is a diagram showing an example of a dust source search range γ (i, i _t). With reference to FIG. 4, dust source search range γ (i, i _t) an example of a setting method will be described.
In FIG. 4, γ (i _M , i _t ) is the same as the dust generation source search region γ (i _M , i _t ) decomposed and displayed for each coordinate component in FIGS. It is expressed in a single figure. In FIG. 4, two dustfall evaluation points i _M and i _N are installed on the ground surface on the absolute coordinates (x ′, y ′, z), and these dustfall assessment points i _M and i _N are used as representative points. elevation upwind direction of the wind direction _{WD (i t) θ (=} tan -1 [V s (i M, i t) / WS (i t)], _{^{or, tan -1 [V s (i}} N, i t ) / in WS (i _t)]), setting the center axis of the dust source search area _{γ (i M, i t)} , γ (i N, i t). Around the central axis, so as to form an elliptical cross-section in the horizontal direction to 2 [sigma] _y, the vertical direction in the 2 [sigma] _z becomes wide, dust source search area _{γ (i M, i t)} , γ (i N, i t ) Is set. As shown in FIG. 4, a plurality of dust sources search area γ (i, i _t) if there is, there may occur a plurality of dust sources search area γ (i, i _t) a common region 41 between .

Next, in step S205, dust source searching apparatus, lowering the dust evaluation point i, "" t _g (k) period maximum dustfall amount M (i, i _t) in a "to become time T _d ( and M _max (i) is a dustfall amount of i _t), and i _max (i) is the i _t in this case, the representative wind direction WD _max · representative wind speed WS _max at the time _{T d} (i _t) "a calculate. In this embodiment, for example, in step S205, a maximum dustfall information deriving step is executed.

Next, the second step will be described.
First, in step S206, dust source searching apparatus, as one of dustfall evaluation point i _M, selects the dustfall evaluation point i unselected.
Next, in step S207, the dust generation source search device selects an unselected coordinate point p.
Next, in step S208, dust source searching apparatus, the position vector Sc of the coordinate point _{p (i x, i y,} i z) calculated. Position vector Sc of the coordinate point p is a starting point the origin of the coordinate axes, i _x th coordinate axes components, respectively, i _y th, i _z th coordinate axis division points become point (i.e., p point) to the end point of the Set to Here, γ (i _M , i _max ) is defined as the first unsteady falling dust search area as “the only unsteady falling dust search area for the falling dust evaluation point i _M ” in the “t _g (k) period”. To do.

Next, in step S209, the dust generation source searching device selects the other falling dust evaluation point i _N different from the falling dust evaluation point i _M. Here, the "unsteady dustfall search area about the dustfall evaluation point i _N" in "t _g (k) any time _{T d} (i _t) of _{period", γ (i N, i t} ) a second The unsteady falling dust search area.
Next, in step S210, dust source searching apparatus, the dustfall evaluation point i _M selected in step S206, and the dustfall evaluation point i _N selected in step S209 whether or not in the same position judge. As a result of the determination, if the falling dust evaluation point i _M and the falling dust evaluation point i _N are at different positions, the process proceeds to step S211. On the other hand, when the falling dust evaluation point i _M and the falling dust evaluation point i _N are at the same position, steps S211 to S220 are omitted and the process proceeds to step S221 described later.

Proceeding to step S211, dust source searching apparatus, among the "t _g (k) period" in the time _{T d} (i _t), selects the unselected time _{T d} (i _t).
Next, in step S212, the dust source search device determines that the coordinate point p selected in step S207 is the first dust source search range γ (i _M , i _max ) and the second dust source search range. It is determined whether or not a dust source determination condition is satisfied that the dust source determination mode is a mode other than “not a dust source” and is included in both of γ (i _N , i _t ).
As a result of this determination, if the dust generation source determination condition is satisfied (all), the coordinate point p selected in step S207 may be a dust generation source. The state that satisfies this dust generation source determination condition is shown in FIG. 4 in the common region 41 (region indicated by oblique lines) of the two dust source search regions γ (i _M , i _t ) and γ (i _N , i _t ). Corresponds to the state where the coordinate point p exists. When the dust generation source determination condition is satisfied in this way, the process proceeds to step S213. On the other hand, when the dust generation source determination condition is not satisfied, steps S213 to S220 are omitted, and the process proceeds to step S221 described later.

When the process proceeds to step S213, the dust generation source search device is the (shortest) distance L _d (i _M ) between the coordinate point p selected in step S207 and the one dustfall evaluation point i _M selected in step S206. Similarly, the (shortest) distance L _d (i _N ) between the coordinate point p selected in step S207 and the other falling dust evaluation point i _N selected in step S209 is calculated.
The distance between the coordinate points p and dustfall evaluation point i _M L _d (i _M), for example, the end point of the position vector P (i _M), the position vector _{Sc (i x, i y,} i z) of Calculated as the norm of the vector connecting the end point. The calculation method of the distance L _d (i _N ) between the coordinate point p and the falling dust evaluation point i _N is also the same. In the present embodiment, for example, a distance calculation step is executed in step S213.

Next, in step S214, the dust generation source searching device “selects dust generation source search areas γ (i _M , i _t ), γ (related to the falling dust evaluation points i _M and i _N at the coordinate point p selected in step S207. i _N , i _t ) of the central axis vertical cross-sectional areas S _p1 , S _p2 ”. The calculation method of the central axis vertical cross-sectional areas S _p1 and S _p2 of these dust generation source search regions γ (i _M , i _t ) and γ (i _N , i _t ) is, for example, as follows. That is, among the diffusion widths σ _y [L _d ] and σ _z [L _d ], the area of the ellipse having the larger axis as the major axis length and the shorter value as the minor axis length. The center axis vertical cross-sectional areas S _p1 and S _p2 of the dust generation source search areas γ (i _M , i _t ) and γ (i _N , i _t ) can be calculated. In the present embodiment, a cross-sectional area calculation step is executed in step S214.

Next, in step S215, the dust generation source searching apparatus calculates “assumed dust generation amounts E ₁ and E ₂ at the coordinate point p selected in step S207” estimated from the falling dust evaluation points i _M and i _N , respectively. calculate. The assumed dust generation amounts E ₁ and E ₂ are calculated using, for example, the following equations (11a) and (11b).
E ₁ = B _{1 Sp 1} M _max (i _M ) (11a)
E ₂ = B _{1 Sp 2} M (i _N , i _t ) (11b)
In Formula (11a) and Formula (11b), B ₁ is a coefficient. Equations (11a) and (11b) correspond to the fact that the local concentration in the general plume equation is proportional to the amount generated at the source and inversely proportional to the local plume cross-sectional area. That is, if the coordinate point p selected in step S207 is a dust generation source, a concentration that is inversely proportional to the plume cross-sectional area at the falling dust evaluation points i _M and i _N is detected. In other words, for a certain detected concentration, the larger the assumed plume cross-sectional area, the greater the amount of generation at the corresponding source. Therefore, the generation amount at the generation source should be proportional to the plume cross-sectional area at the falling dust evaluation points i _M and i _N.

B ₁ in the equations (11a) and (11b) is a coefficient that should be changed by a number of parameters such as weather conditions. However, as described below, in the present embodiment, only the ratio of the assumed dust generation amounts E ₁ and E ₂ is used in determining the dust generation source. Further, since the assumed dust generation amounts E ₁ and E ₂ are calculated based on the data at the same time, the assumed weather conditions are common. Therefore, in the present embodiment, B ₁ can be set as a constant as a simple method. In this embodiment, for example, in this step S215, a dust generation amount calculating step is executed.

Next, the third step will be described.
First, in step S216, the dust generation source search device calculates a ratio R of the assumed dust generation amounts E ₁ and E ₂ . The ratio R between the assumed dust generation amounts E ₁ and E ₂ may be E ₁ / E ₂ or E ₂ / E ₁ .
Next, in step S217, the dust source search device determines whether the coordinate point p selected in step S207 is a dust source. In the present embodiment, the dust source search device determines whether or not the ratio R of the assumed dust generation amounts E ₁ and E ₂ is within a preset upper and lower threshold value range (R _max ≧ R ≧ R _min ). Determine. As a result of the determination, if the ratio R between the assumed dust generation amounts E ₁ and E ₂ is within the preset upper and lower threshold values, it is determined that the coordinate point p selected in step S207 is a “dust generation source”. Is done. On the other hand, if the ratio R between the assumed dust generation amounts E ₁ and E ₂ is outside the preset upper and lower threshold values, the coordinate point p selected in step S207 is determined to be “not a dust generation source”.

The basis of this judgment method is as follows. By definition, the fluctuation in the amount of dust generated from an unsteady dust generation source whose time scale is greater than or equal to the period Δt _g is sufficiently small within the “t _g (k) period”. Therefore, as long as a search is made for a dust generation source having a larger dust generation amount than other dust generation sources, that is, a main dust generation source, the falling dust generated from the main dust generation source is “t _g (k) It is considered dominant at all falling dust evaluation points i that can be reached during the “period”. At this time, if there are a plurality of falling dust evaluation points i that can be reached during this “t _g (k) period”, the amount of falling dust observed at these falling dust evaluation points i is determined by the dust source ( According to a function of the distance between the coordinate point p) and each of the falling dust evaluation points i (that is, a plume equation), they should exhibit a constant ratio. Therefore, the coordinate point p satisfying this condition is highly likely to be a main dust source. Therefore, when the ratio R between the assumed dust generation amounts E ₁ and E ₂ is within the preset upper and lower threshold values, it is determined that the coordinate point p selected in step S207 is a “dust generation source”.

On the other hand, if the ratio of the amount of dustfall observed at each dustfall evaluation point i is significantly different from the value calculated from the plume equation, the coordinate point p selected in step S207 is “t _g ( k) Even if the coordinate point p exists at a position where the falling dust can reach the plurality of evaluation points i during the “period”, there is a high possibility that it is a false dust generation source. Therefore, when the ratio R between the assumed dust generation amounts E ₁ and E ₂ is outside the range of the preset upper and lower threshold values, it is determined that the coordinate point p selected in step S207 is not a “dust generation source”.

As a result of the determination, if the coordinate point p selected in step S207 is a dust generation source, the process proceeds to step S218. On the other hand, if the coordinate point p selected in step S207 is not a dust generation source, the process proceeds to step S220 described later.
In the present embodiment, for example, a dust generation source determination step is executed in step S212 and step S217.
In step S218, the dust source search device sets the dust source determination mode at the coordinate point p selected in step S209 to “dust source”.
Next, in step S219, the dust generation source search apparatus calculates an estimated dust generation amount at the coordinate point p determined to be a “dust generation source”. The estimated dust generation amount can be, for example, an average value of all assumed dust generation amounts E used in the dust source determination (step S217) at the coordinate point p determined to be the “dust generation source”. . And it progresses to step S221 mentioned later.
On the other hand, when the process proceeds to step S220, the dust source search device sets the dust source determination mode at the coordinate point p selected in step S207 to “not a dust source”. Then, the process proceeds to step S221.

In step S221, dust source searching apparatus determines whether selected "t _g (k) period" all the time T _d in the (i _t). As a result of the determination, if you do not select the "t _g (k) period" all the time T _d in the (i _t), the process returns to step S211. On the other hand, when selecting "t _g (k) period" all the time T _d in the (i _t), the process proceeds to step S222.
In step S222, the dust generation source search device determines whether or not all the falling dust evaluation points i have been selected as the other falling dust evaluation points i _N. The result of this determination, as the other dustfall evaluation point i _N, if not select all of dustfall evaluation point i, the process returns to step S209. On the other hand, when all the falling dust evaluation points i are selected as the other falling dust evaluation point i _N , the process proceeds to step S223.
In step S223, the dust generation source search device determines whether all coordinate points p have been selected. If all the coordinate points p are not selected as a result of this determination, the process returns to step S207. On the other hand, if all coordinate points p have been selected, the process proceeds to step S224.

In step S224, the dust generation source search device determines whether or not all the falling dust evaluation points i have been selected as one of the falling dust evaluation points i _M. The result of this determination, as one dustfall evaluation point i _M, if not select all of dustfall evaluation point i, the process returns to step S206. On the other hand, when all the falling dust evaluation points i _M are selected as one of the falling dust evaluation points i _M , the process proceeds to step S225.
In step S225, the dust source search device displays the position of the dust source and the estimated dust generation amount in the dust source. And the process by the flowchart of FIG. 3 is complete | finished. Note that not all coordinate points p may be determined as dust generation sources. In this case, in step S225, the dust generation source search device displays that fact.

As described above, the second, the third step, "t _g (k) period" can be performed for every time _{T d} (i _t) in respect to particular coordinate points p, a specific time T _d (i The determination result of whether or not it is a dust generation source at _t ) can be the determination result of whether or not it is a dust generation source representing the “t _g (k) period”. In the coordinate points p selected in step S207, it is determined as "not a dust source" at any time _{T d} (i _t), the coordinate point p in this "t _g (k) period" It is determined that it is not the main dust source. On the other hand, in any of the time _{T d} (i _t), the coordinate point p is determined to be "Hatsuchirigen", and, when it is determined as "not a dust source" at any time other than it , the coordinate point p is determined as "a major dust source in t _g period".

Further, in the second and third steps, the dust falling evaluation points i _M and i _N and the coordinate point p may be changed as necessary to independently determine whether or not the dust generation source is generated. . At the coordinate point p that is not given to the determination of any dust generation source, the initial value “Undetermined” remains as the dust source determination mode. Moreover, you may complete | finish a process when a dust generation source is obtained.
In the second step and the third step, a dust source is determined for a specific coordinate point p with respect to a specific dust fall / dust assessment point i (= i _M ) (the dust source judgment mode is any Set it up). If necessary, the dust fall evaluation point i and the coordinate point p are changed and the same determination is performed.
Thus, in the present embodiment, the source search region is extended to the upwind direction from the evaluation point p, by introducing the concept of the plume type, time scale is not less than the period Delta] t _g, the dustfall generation source It becomes possible to accurately identify the dust generation amount at the position and the generation source. Therefore, it becomes possible to efficiently and accurately search for dust sources including unsteady dust sources by measuring the amount of dust fall at a small number of dust fall evaluation points.

(Second Embodiment)
Next, a second embodiment of the present invention will be described.
When it is known in advance that the dust source is limited to the height near the ground surface, the dust source search region is not a three-dimensional region as in the first embodiment, but in a horizontal plane (two-dimensional By setting within the region, it is possible to simplify the process of searching for a dust source, and to reduce the impossibility of calculation required for searching the dust source.

Specifically, in step S204 of FIG. 3, the dust generation source search device tilts the central axis of the dust source search area γ (i _M , i _t ), γ (i _N , i _t ) in the vertical direction. And the vertical diffusion width σ _z is omitted (the elevation angle θ is 0 ° and the diffusion width σ _z is 0), and the dust source search regions γ (i _M , i _t ) and γ (i _N , i _t ) are 2D.
The position vectors P and Sc in steps S202 and S208 are also converted into two-dimensional vectors by omitting vertical components.

However, even when the dust generation source search region γ (i _M , i _t ) and γ (i _N , i _t ) are two-dimensionalized in this way, the dust generation amount at the coordinate point p is calculated. Therefore, it is necessary to consider the effect of vertical diffusion of the dust plume. For this reason, in step S214, the dust source search device determines that “the dust source search areas γ (i _M , i _t ) and γ (related to the falling dust evaluation points i _M and i _N ” at the coordinate point p selected in step S207. i _N , i _t ), the central axis vertical cross-sectional areas S _p1 and S _p2 ”must be calculated. The center axis vertical cross-sectional areas S _p1 and S _p2 of the dust generation source search areas γ (i _M , i _t ) and γ (i _N , i _t ) related to the dustfall evaluation points i _M and i _N have already been calculated. A cross-sectional area of a circle having a radius of “horizontal diffusion width σ _y [L _d ]” of the falling dust particles at the distances L _d (i _M ) and L _d (i _N ) can be used. Or, "the distance L _d (i _M)," horizontal diffusion width of dustfall particles in _{L d (i N) σ y} [L d] corresponds to the "" distance _{L d (i M), L} d ( The cross sectional area of an ellipse whose major and minor axes are 2 × σ _y or 2 × σ _Z may be obtained by using “vertical diffusion width σ _z [L _d ]” of the dust particles falling in i _N ).

In this embodiment, the "t _g (k) period" each time T _d contained in the (i _t), wind direction and wind speed varies generally. In the present embodiment, since the main dust generation sources related to the specific dust fall evaluation point i _M are searched, the windward WD _max (i _M ) windward having the maximum dust fall amount in the “t _g (k) period”. It is natural to set the first dust source search range γ (i _M , i _t ) in the direction. In order to identify a dust source within the first dust source search range γ (i _M , i _t ), the second dust source search region γ (i _N , i _t at another evaluation point i _N is used. ) And the first source of dust generation. In the present embodiment, the amount of dust fall at the dust fall evaluation point i _N at the time when the wind direction WD (i _N , i _t ) is different from the wind direction WD _max (i _M ) within the “t _g (k) period”. measured value M (i _N, i _t) by using a "first, second dust source search area _{γ (i M, i t)} , γ (i N, i t) intersection of liable Thus, the presence / absence of the dust generation source can be determined at more coordinate points p, and the “undetermined” coordinate points p can be reduced.

At this time, the wind direction WD (i _N , i _t ) does not need to be the wind direction when the maximum amount of dust fall is measured at the dust fall evaluation point i _{N as} in the conventional method. In the embodiment of the present invention, there is an estimated value of the dust generation amount in the dust source search area based on the plume formula, so whether or not the wind direction is the maximum dust fall amount as in the conventional method. In addition to the above information, information on the absolute value of the measurement value of the amount of dust fall in a specific wind direction (that is, not relative information on the amount of dust fall under other wind direction conditions) is used to determine the presence or absence of a dust source. This is because it can be applied.

Advantages of the embodiment of the present invention will be described using the same target system as that in FIG. 7, which is a schematic diagram for explaining a generation source search method in the conventional method. As described above, in the prior art, in FIG. 7, the intersections 6, 7, and 8 of the source search lines 2, 3, and 4 are regarded as dust generation sources. However, the conventional technology lacks information on the amount of generation on the source search lines 2, 3, and 4. For this reason, no further information can be obtained on whether these individual intersections 6, 7, 8 are valid as dust sources. For example, the intersection point 6 may actually be a major source, but apparently occurs only at this intersection point 6 due to the influence of the other major dust sources on the falling dust evaluation points i ₁ and i ₂ . The source search lines 2 and 3 may have just intersected (for example, the main generation source related to the falling dust evaluation point i ₁ is the intersection 7 and the main generation source related to the falling dust evaluation point i ₂ is the intersection 8. Or, it may be an unknown source that is located closer to the falling dust evaluation point i ₂ than the facility (dust (SPM) generation point) c). In the conventional method, it is impossible to determine which of these is a true dust generation source. In particular, when an intersection of source search lines 2, 3, and 4 occurs at a point that is not assumed to be a source (for example, intersections 7 and 8), is this intersection an unknown dust source, or It is not possible to identify whether it is just an apparent source search line intersection (ie, not a source). Therefore, the dust generation source is over-detected (when all the intersections are determined to be generation sources), or the detection of an unknown dust generation source is impossible (a generation source at a point not previously assumed as a generation source) It was inevitable that one of the above problems was detected).

FIG. 5 is a diagram schematically illustrating an example of a method for searching for a dust generation source in the embodiment of the present invention.
As shown in FIG. 5, when the embodiment of the present invention is applied, it is possible to examine whether or not the dust generation source is appropriate as a dust generation source in the intersection region of the dust generation source search region. That is, for example, in FIG. 5, dust source search areas γ (i ₁ , i _tmax ), γ (i ₂ , i _tmax ), as dust falling evaluation points corresponding to the intersections 6, 7, and 8 in FIG. It is assumed that coordinate points p ₁ , p ₂ , and p ₃ existing in the common region between γ (i ₃ , i _tmax ) are obtained. In this case, for example, to assess the validity of the dust source coordinate point p ₁ are each the dustfall evaluation point i ₁ and i ₂ of the coordinate points p ₁ against estimator dust amount E (p _1, By comparing i ₁ ) and E (p ₁ , i ₂ ), the dust source can be determined quantitatively.

  Further, in principle, the conventional method can only search for a source in a direction in which the concentration detection amount for each wind direction shows a maximum value (at least a maximum value). In the case of searching for an unsteady dust generation source, since the measurement period is relatively short, fluctuations in the wind direction during this period are generally limited. Accordingly, it is practically impossible to obtain concentration measurement values under all wind direction conditions at each dustfall evaluation point. For this reason, depending on the combination of the main source, the dustfall evaluation point, and the wind direction range from which the measured value can be obtained, the wind direction that should originally exhibit the maximum concentration value at the specific dustfall evaluation point is during the measurement period. Therefore, the source search may not be possible (or false identification). Originally, even concentration measurements under limited wind direction conditions should have some information about the source. Therefore, if a dust source search can be performed in the direction in which the wind direction data exists (for example, if a source search line such as the source search line 5 shown in FIG. 7 can be set), at least another dustfall evaluation Information useful for identifying the source at a point may be provided. However, in the conventional method, there is no method for setting a source search line like the source search line 5 shown in FIG. 7, so that concentration measurement data other than the wind direction indicating the maximum concentration value can be used. Absent.

FIG. 6 is a diagram schematically illustrating an example of a method for setting the dust generation source search region in a direction other than the wind direction indicating the maximum concentration value.
In an embodiment of the present invention, as shown in FIG. 6, to set the density maximum dust source in a direction other than the wind indicating the search area (e.g., dust source search area _{γ (i 3, i t2)} ) be able to. As a result, such dust source search area γ (i _1, i _tmax) and γ (i _3, i _t2) coordinate points p ₄ within the common area of the conventional, even in a region which could not be evaluated for dust source In addition, the presence / absence of a dust source can be determined. As a result, the coordinate point p at which the presence / absence of the dust source can be determined can be dramatically increased as compared with the conventional method, and a more precise dust source search can be performed.

Furthermore, in the conventional method shown in FIG. 7, since the determination of the presence or absence of a dust source is performed on a two-dimensional plane, all the intersections 6, 7, and 8 of the dust source search lines 2, 3, 4 are defined as dust sources. There was a harmful effect of seeing. In contrast, in the first embodiment of the present invention, dust source search area gamma (i, i _t), using the analysis result of the particle size of the dustfall samples obtained in dustfall evaluation point i , Expanded on a three-dimensional space. For this reason, in the conventional method, even if the dust source search ranges seem to intersect each other at first glance in the plan view as shown in FIG. There are many cases where there is no common area. Therefore, in the embodiment of the present invention, among the specific points corresponding to the intersections 6, 7, and 8 on the plane as shown in FIG. 7, it cannot actually be a dust generation source (that is, three-dimensional). Points that are not included in the common area between the dust source search areas in space can be excluded from the dust source candidates. Thereby, the search for the dust generation source can be performed with higher accuracy.
As described above, according to the embodiment of the present invention, it is possible to set more coordinate points p that can be candidates for the dust generation source while excluding the coordinate points p that cannot be the dust generation source. In p, the position of the dust generation source and the amount of dust generation at the dust generation source can be specified with higher accuracy.

(Third embodiment)
Next, a third embodiment of the present invention will be described.
Based on the intensity of the dustfall collected at the evaluation point and measuring the intensity, individual fallen dust particles (or samples) or the entire fallen dust particles (samples) are subjected to radioactive dustfall or non-radiative precipitation. It is possible to search for a non-stationary dust generation source of radioactive fallen dust (or non-radioactive fallen dust) that is classified as soot dust and that targets only radioactive fallen dust (or only non-radiative fallen dust).
A known method can be used as a method for measuring the radiation intensity of the falling dust. For example, the methods described in Patent Documents 7 to 9 can be used.
The classification method of dustfall sample based on the radiation intensity, for example, each of the T _d (i _t) period (time T _d (i _t -1) from time T _d (i _t) to the time (period)) Individual falling dust particles in the sample collected at the evaluation point are separated one by one and their respective radiation intensities are measured. If the radiation intensity is equal to or higher than a predetermined threshold, the falling dust particles having the radiation intensity are separated. It can be classified as radioactive fallen dust, and the others can be classified as non-radioactive dustfall. The total mass of this sample is measured as the amount of dustfall, so the ratio of the number of radioactive dustfall to the total mass of the sample (= [number of radioactive dustfall / (number of radioactive dustfall + number of non-radiative dustfall) The value multiplied by the number)]) can be used as the mass of radioactive dust falling in this sample. Alternatively, when the radiation intensity of the entire sample of the collected dust particles is measured and the radiation intensity is equal to or greater than the predetermined threshold, the mass of the entire sample is taken as the mass of radioactive dust. Otherwise, Alternatively, the mass of the entire sample may be the mass of the non-radioactive dust sample. In step S102 in FIG. 3, the mass of the radioactive dustfall thus obtained (or the mass of non-radioactive dustfall) is set as the dust fall amount M (i). Then, any one of “dust generation source”, “not a dust generation source”, and “undecided” is set for radioactive dustfall (or non-radiative dustfall).
By such handling, for example, an unsteady dust generation source of radioactive dust fall can be identified using the dust fall measurement data at a distance without approaching the radioactive dust source. In addition, as to which of the radioactive dustfall and non-radiation dustfall is to be searched for the dust generation source, for example, before starting the flowchart of FIG. 3, a keyboard or console screen connected to the information processing apparatus is used. And can be set (input) manually in advance.

The embodiment of the present invention described above can be realized by a computer executing a program. Further, a computer-readable recording medium in which the program is recorded and a computer program product such as the program can also be applied as an embodiment of the present invention. As the recording medium, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.
In addition, the embodiments of the present invention described above are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

i dustfall evaluation point i _o Hatsuchirigen a, b, c, d, the central axis of the central shaft 11 dust source search area e advance source p coordinate point α plume γ dust source search range 10 plume envisaged 41 Common area between dust source search areas

Claims (5)

In time period Delta] t _d each of i _t-th time _{T d} (i _t), different in the two or more dustfall evaluation point, from time _{T d} (i _t -1) to the time _{T d} (i _t) to each other a dust amount setting step of setting an average measure of the dustfall amount M at _{T d} (i _t) period in,
Based on the wind direction continuously measured at the time period Δt _wint shorter than the time period Δt _d in the vicinity of each of the _dustfall evaluation points, the representative wind direction WD (i) in the T _d (i _t ) period is used. _t )) to derive the representative wind direction,
Based on the wind speed continuously measured at the time period Δt _wint shorter than the time period Δt _d in the vicinity of each of the _dustfall evaluation points, the representative wind speed WS (i) during the T _d (i _t ) period is used. _t ) representative wind speed deriving step,
Based on the measured value of the drop rate of the _{T d} (i _t) period is collected in the dustfall evaluation point was dustfall, a representative falling speed deriving step of deriving a representative falling velocity V _s of the dustfall,
The time t _g (k−1) when the k th time is t _g (k), each time period Δt _g including two or more consecutive times T _d (i _t ). from time t _g (k) to any of the _{T d} (i _t) drops in the period dust search area γ (i, i _t) included in t _g (k) period is an evaluation period as two different mutually Starting from the falling dust evaluation points i _M and i _N and having a central axis extending in the upwind direction of the representative wind direction WD, a falling dust generation source search region width is provided around the central axis, First and second falling dust generation source search areas γ (i _M , i _t ) and γ (i _N , i _t ) having the range of the distance to the falling dust generation source search area width as an area in the vertical direction A dustfall generation source search area setting step to be set;
For the dustfall evaluation point i, t _g (k) and the time the maximum dustfall amount M in the period _{T d} (i _t) dustfall amount M _max (i), the time _{T d} (i _t) i _max and (i) is i _t in, and a maximum dustfall information deriving step of deriving the WD _max and WS _max is a representative wind direction and the representative wind speed at the time _{T d} (i _t),
t _g (k) first dustfall generation source search region is the only non-stationary dustfall search area about the dustfall evaluation point i _M in the period γ (i _M, i _max) and, t _g (k) period any time _{T d} (i _t) the dustfall evaluation point i _M different dustfall evaluation point i _N for the second dustfall generation source search area γ and the (i _N, i _t) in both the A distance calculating step of calculating distances L _d (i _M ) and L _d (i _N ) between the coordinate point p located at 2 and the two dustfall evaluation points i _M and i _N ;
The dust source search area center that is a cross-sectional area of the first and second dustfall generation source search areas in the vertical plane of the central axis of the first and second dustfall generation source search areas including the coordinate point p A cross-sectional area calculating step of calculating the axial vertical cross-sectional areas S _p1 and S _p2 using the falling dust source search area width,
A dust generation amount calculating step of calculating assumed dust generation amounts E ₁ and E ₂ proportional to the dust source search region central axis vertical sectional areas S _p1 and S _p2 ;
The ratio of any one of the assumed dust generation amounts E ₁ and E ₂ calculated in the dust generation amount calculation step with respect to all combinations of all the falling dust generation source search regions including the coordinate point p is If all are within the range of the predetermined upper and lower thresholds, the coordinate point p is determined to be a main unsteady dust generation source having a time scale equal to or greater than the time period Δt _{g in the} period t _g (k), If the ratio of any one of the assumed dust generation amounts E ₁ and E ₂ calculated in the dust generation amount calculating step is outside the range of the predetermined upper and lower threshold values, the coordinate point p is set to the period t _g (k). with determined not to be a major non-stationary dust sources having more time scale time period Delta] t _g in, the coordinate points in the case where the coordinate point p is not included in any of the dustfall generation source search area Do not judge non-steady dust generation source of dustfall at p A determination step,
Have
The descending dust generation source search region width is a plume diffusion width calculated at the distance on the plume central axis with the plume type dust generation source search region central axis as a plume central axis in a plume formula. Search method of unsteady dust source position of soot dust. The lower dust generation source search area central axis has the upwind direction of the wind direction as a horizontal component, and a value V _s / WS obtained by dividing the representative falling speed V _s of the falling dust by the representative wind speed WS as a vertical gradient. Have
As the descending dust generation source search area width, the plume diffusion width σ _{y in the} horizontal direction and the vertical calculated in the plume formula at the distance on the plume center axis with the central axis of the falling dust generation source search area as the plume central axis. The method for searching for the unsteady dust generation source position of the falling dust according to claim 1, wherein the plume diffusion width σ _z in the direction is used as a horizontal component and a vertical component, respectively. The plume diffusion widths σ _y and σ _z , the distance x from the source on the plume central axis, the dust generation amount Q _P , the representative speed WS, the constant B, and the plume diffusion widths σ _y and σ _z The plume range defined by using the following formulas (A) and (B) expressing the dust concentration C (x) at the distance x from the source on the plume central axis using the plume: The method for searching for the unsteady dust generation source position of the falling dust according to claim 1 or 2, wherein the method is used as an equation.
C (x) = B (Q _P / 2πσ _y σ _z WS) (within the plume range) (A)
C (x) = 0 (outside the plume range) (B) Among the plume diffusion widths σ _y and σ _z , an ellipse having a longer axis twice as a major axis and a shorter axis twice as a minor axis is a plume cross-sectional shape perpendicular to the plume central axis. The method for searching for the unsteady dust generation source position of the falling dust according to claim 3, wherein the plume range is calculated by setting the inside of the ellipse as the plume range. There is further provided a dust type classification step of measuring the radiation dose of the falling dust sample collected at the evaluation point during the T _d (i _t ) period and classifying the falling dust sample for each dust type based on its intensity. And
2. The mass of the falling dust in the portion corresponding to any one of the dust types classified in the dust type classification step among the collected dust falling samples is defined as the amount of dust falling M. The search method of the unsteady dust generation source position of the falling dust of any one of thru | or 4.

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