A ruler for mixing the ingredients of a selected beverage is slidably received in a vertical slot formed on the inside wall of a pitcher. The beverage ingredients for mixing are listed on each side of the ruler. The list of ingredients for each beverage is color coded to distinguish one beverage from another. The amount and order for mixing the ingredients in the pitcher are identified by parallel spaced measuring lines extending from the bottom to the top of the ruler. The lowermost measuring line on the ruler identifies the first ingredient added to the pitcher. The remaining ingredients are sequentially added to the pitcher to the level of the measuring line identifying each ingredient. The ingredients for mixing are added to the pitcher without requiring the volume of each ingredient to be separately measured and added. With the mixing ruler being releasably attached to the pitcher a set of mixing rulers for a collection of beverage recipes is available for use in mixing beverages in the pitcher.

1. Field of the Invention
The present invention relates to method and apparatus for preparing and dispensing beverages from a pitcher and, more particularly, a pitcher for receiving the ingredients for mixing both alcoholic and non-alcoholic beverages where the ingredients for the beverage to be mixed and the amount of each ingredient are identified by a measuring ruler releasably attached to the pitcher where a plurality of measuring rulers are provided for mixing the ingredients of any number of beverages.
2. Description of the Prior Art
It is a well known practice in the use of a mixing cup for cooking to identify on the cup the levels at which ingredients are added to the cup. For example, the exterior of a mixing cup is marked to identify the levels for filling ingredients from one-fourth cup to a full cup. Measure lines extend from the bottom of the cup to the open upper end of the cup. A one-half cup of sugar is measured by adding sugar to the cup to the measuring line that is identified as one-half cup.
On another portion of the circumference of the measuring cup, measuring lines identify increments in ounces from the bottom level of the cup at two ounces to the top level at eight ounces. The measuring marks are imprinted on the surface of the cup and are visible from the outside of the cup. The information that can be printed on the cup is limited by the circumferential surface area of the cup.
In the mixing of beverages that include a number of different ingredients, such as an alcoholic beverage, it is well known to use cocktail shakers for mixing ingredients in the required amounts. In one embodiment the circumference of the cocktail shaker is marked with the names of a number of cocktails to be mixed followed by a list of the ingredients. For example, the cocktail shaker identifies the ingredients of a margarita to include 4 oz. of tequila, 2 oz. of Cointreau and 1 oz. of lemon juice. The same approach is used to identify other cocktails, such as a Manhattan, daiquiri, martini, bloody Mary, and the like.
The ingredients by volume of each cocktail appears on one portion of the circumferential surface of the cocktail shaker. Another portion of the circumference of the cocktail shaker is imprinted with measure lines for identifying volume in ounces beginning at the bottom with one ounce and progressing vertically to the top of the cocktail shaker to, for example, 15 oz. A measure line is provided for each ounce from one to fifteen ounces. Using the shaker to mix a margarita, you would add tequila in the amount of 4 oz. to a level opposite the 4 oz. mark. From the 4 oz. mark, 2 oz. of Cointreau would be added to the 6 oz. mark and then 1 oz. of lemon juice would be added to the 7 oz. mark for a margarita containing 7 oz. of ingredients.
There are a number of disadvantages with the above-described cocktail shaker. Principally, the number of different beverages identified on the shaker for mixing is limited by the circumferential surface area available for identifying the ingredients for each cocktail. Typically, the ingredients for no more than six different beverage would be listed around the circumference of the shaker, leaving room to print the measuring scale. With this arrangement one scale in ounces is provided on the cocktail shaker for mixing the ingredients of each beverage.
Each cocktail has different ingredients added at different volumes to the shaker. Therefore, a single scale must be provided identifying increments of ounces from one ounce to an upper limit, for example eight or ten ounces. Furthermore, each ingredient is added one by one to the shaker by an ounce container (shot glass) by the volume required for the cocktail. For example, after 4 oz. of tequila are added to the shaker, 2 oz. of Cointreau are added to the measuring line identifying 6 oz. Again, this requires adding the required volume beginning with the volume of the last ingredient added to the vessel. This makes it difficult to precisely measure the ingredients that are to be mixed together.
There is need for a beverage mixing device that can be used to identify the ingredients of any number of beverages where the user knows exactly to what level in the mixing device the selected ingredients are added.

Pitcher and mixing ruler for preparing and dispensing beverages


According to one or more embodiments of the disclosure, a particular networking device joins a ring network of networking devices that has a ring topology. The particular networking device monitors the ring network for a multicast frame used within the ring network to detect link failures. The particular networking device determines that a link in the ring network has failed, based on the particular networking device not receiving the multicast frame within a threshold amount of time. The particular networking device initiates repair of the ring network, when the particular networking device determines that the link in the ring network has failed.

Operational Technology (OT) networks are typically used to automate processes, such as factories, buildings, etc. Increasingly, OT networks are making use of networking devices that form a ring topology. Indeed, it is now common to see many rings of OT networks connecting various other ring networks or endpoint such as sensors, input/output (I/O) devices, and the like, through the ring topology and back to the enterprise. In general, ring topologies afford additional resiliency to the network, in the case of link failure.
When a link fails in a ring network, the amount of time taken by the network to identify the failure, and to redirect its traffic to avoid the failed link, is generally referred to as the convergence time for the ring network. In OT deployments, the convergence time can be a critical factor, as OT networks often support processes that require sub-second signaling. For instance, if a ring in an OT network conveys control commands to a particular actuator, a link failure in that ring may result in the actuator ceasing to function until the failure is detected and the network converges. With ring networks that include a large number of networking devices (e.g., Ethernet switches, etc.), the convergence time has been found to grow with each networking device that is added to the ring. This means that a network architect typically has to make a tradeoff between the size of the ring network and the convergence time that the ring is able to achieve.

Network convergence mechanism for ring networks


The present disclosure provides a scanned image correction apparatus, method and a mobile scanning device. The apparatus includes an image collector, an arm swing detector, and an image processor. The image collector is configured to collect a scanned image of an object under inspection during a scanning process of scanning the object under inspection by the mobile scanning device, and determine an image parameter of the scanned image. The arm swing detector is disposed at a monitor point on a detector arm of the mobile scanning device, and configured to detect a displacement offset of the detector arm in a specified direction and build an arm swing model of the detector arm. The image processor is configured to determine a change relationship between the image parameter of the scanned image and the displacement offset of the detector arm, and correct the scanned image based on the change relationship.

A mobile scanning device adopts a cantilever structure, and a detector boom may inevitably sway during a scanning process. Especially at present, there are more and more scanning devices with a large scanning channel. As the scanning channel becomes larger, the swing of the detector boom is intensified. The swing of the detector boom will cause fluctuation of an amount of radiation received by a detector located at the detector boom, resulting in bright and dark stripes on a scanned image. The stripes caused by the swing of the detector boom will degrade image scanning indexes such as spatial line resolution, contrast line resolution and spatial line pairs, and thus affect the imaging quality.
Conventionally, the swing of the detector boom may usually be restricted by installing a locking device, but in this way, the improvement on the imaging quality has a low accuracy and the improvement effect is poor.

Scanned image correction apparatus, method and mobile scanning device


A variety of molded bodies having high weatherability, impact resistance, designability, and the like, and a polyorganosiloxane latex and a graft copolymer used as the raw materials therefor are provided, where the polyorganosiloxane latex has a mass average particle diameter (Dw) of a polyorganosiloxane particle of 100 to 200 nm, and a ratio of the mass average particle diameter (Dw) to a number average particle diameter (Dn) (Dw/Dn) of 1.0 to 1.7. A polyorganosiloxane-containing vinyl-based copolymer (g) obtained by polymerizing one or more vinyl-based monomers in the presence of the latex. A graft copolymer (G) is obtained by graft polymerizing one or more vinyl-based monomers in the presence of the copolymer. A thermoplastic resin composition includes the graft copolymer (G) and a thermoplastic resin (Ha) except for the graft copolymer (G). A molded body is obtained by molding the resin composition.

Polyorganosiloxane latexes are widely used as raw materials for resin additives, fiber treatment agents, mold release agents, cosmetics, antifoaming agents, additives for a coating material, and the like. Various methods have been proposed as the method of producing a polyorganosiloxane latex. For example, Patent Literature 1 and Patent Literature 2 describe polyorganosiloxane latexes obtained by emulsion polymerizing organosiloxane in an aqueous medium.
Polyorganosiloxane in a latex exhibits different properties depending on the particle diameter. When a polyorganosiloxane latex is used as a raw material for resin additives, fiber treatment agents, mold release agents, cosmetics, antifoaming agents, additives for a coating material, and the like, a polyorganosiloxane latex having the particle diameter optimal to the application is required in order to exhibit the performance which each of these target products requires. Thus, polyorganosiloxane having a controlled particle diameter and particle diameter distribution is useful.
For polyorganosiloxane contained in the latexes produced by the methods described in these Patent Literatures, the mass average particle diameter (Dw) is 150 to 800 nm, particle diameter distribution (Dw/Dn) expressed as a ratio of the mass average particle diameter (Dw) to the number average particle diameter (Dn) is 1.2 or less (Patent Literature 1), the number average particle diameter is 100 nm or less, and the standard deviation of the particle diameter is 70 nm or less (Patent Literature 2) as described in these Patent Literatures. Unfortunately, the methods described in these Patent Literatures actually have difficulties to obtain polyorganosiloxane having the mass average particle diameter of 100 nm to 200 nm and Dw/Dn of 1.7 or less.
Automobile lights such as a taillight, a brake light, and a headlight for automobiles mainly include a lens made of a transparent resin such as a polymethyl methacrylate (PMMA) resin and a polycarbonate (PC) resin and a housing that supports the lens. Among these, the housing is partially exposed to the sunlight outdoors. For this reason, the housing formed of a material having high weatherability has been desired in these days.
In production of the automobile light in the related art, the lens is bonded to the housing with a hot-melt adhesive, and integrated. To increase productivity, recently, the lens is bonded to the housing by a vibration welding method in some cases. Here, the vibration welding method is a welding method utilizing frictional heat in which in the state where the periphery end of the lens is pressed against the periphery end of the housing, vibration having a amplitude of 0.5 mm to 2.0 mm and the number of vibration of 200 Hz to 300 Hz is applied to generate frictional heat between the lens and the housing; thereby, the lens and the housing are fused, bonded, and integrated. In such a vibration welding method, the finished bonded portion of the lens and the housing needs to have a good appearance.
For the material for vibration welding, a thermoplastic resin composition containing a graft copolymer containing a composite rubber-based polymer consisting of polyorganosiloxane including vinyl polymerizable functional group-containing siloxane and alkyl (meth)acrylate rubber is disclosed.
A thermoplastic resin molded body for automobile parts and casings for a variety of electrical appliances may be subjected to a plating surface treatment for forming a metallic film made of a material such as copper, chromium, and nickel on the surface of the molded body to enhance designability and other functionalities. Moreover, a metallization treatment for forming a metallic film of aluminum, chromium, or the like (thickness of several dozen nanometers to several hundred nanometers) may be performed on the surface of the thermoplastic resin molded body by a vacuum deposition method, a sputtering method, or the like.
In the latter metallization treatment, to enhance the brightness of the molded body, an undercoat layer is usually formed by coating or plasma polymerization in advance before performing metallization treatment. Further, to protect the metallic film obtained by metallization treatment, a top coat layer composed of a silicon-based material or the like is usually formed.
Thus, conventional metallization treatment needs many steps, a dedicated apparatus, and an expensive treatment agent, while the so-called "direct deposition method" eliminating the step for forming the undercoat layer is used these days. The designability of the molded body obtained by the direct deposition method easily changes according to the kind of resin materials and the state of the surface of the molded body. For this reason, one of important problems is to stably maintain a beautiful bright appearance of the surface without fogging.
For the resin material suitable for the direct deposition, Patent Literature 3 discloses a thermoplastic resin containing a rubber-containing graft copolymer prepared by graft polymerizing a vinyl-based monomer with a rubber-based polymer having specific particle diameter distribution. Moreover, Patent Literature 3 discloses a thermoplastic resin composition in which the mass average particle diameter of the rubber-based polymer and the proportion of the component (% by mass) have a specific relationship.
Meanwhile, automobile members tend to be lighter these days. For this reason, the automobile members need to have higher physical properties such as impact resistance than ever. In addition to high heat resistance, the level of a demand for a beautiful bright appearance has been increased year after year. Unfortunately, the thermoplastic resin composition disclosed in Patent Literature 3 cannot sufficiently meet the recent demand for high brightness and impact resistance.
Further, recent thermoplastic resin compositions used for vehicle members and construction members need high mechanical strength under a low temperature. Efforts have been made so far to improve the surface appearance and impact resistance of the molded article made from a composite rubber-based graft copolymer prepared from a polyorganosiloxane rubber and an acrylic rubber in combination and the performance of impact resistance. For example, Patent Literature 4 discloses a thermoplastic resin composition comprising a polyorganosiloxane/acrylic composite rubber-based graft copolymer in which the average particle diameter is 10 to 70 nm and the proportion of particles having a particle diameter more than 100 nm is 20% or less based on the total particle volume. Such a resin composition, however, cannot achieve the performance that sufficiently meets the recent demand.

Polyorganosiloxane latex, graft copolymer using the same, thermoplastic resin composition, and molded body


A transmit process that limits the time during which a reduced network bandwidth exists between two powerline nodes because a receiving node fails to respond to frame transmission attempts by a transmitting node is described. The transmit process restricts the number of retries that occur in a lower date rate transmission mode and, for a predetermined time period to follow, drops all subsequent frames destined for the non-responding node.

The invention relates generally to network congestion control.
As broadband access expands and the number of Web-enabled devices used by consumers grows, emerging powerline networking technology allows consumers to plug those devices into ordinary house electrical outlets, thus turning existing residential wiring into a high speed data network. Unlike more conventional networks like Ethernet networks, however, powerline networks are susceptible to unpredictable noise and interference from numerous sources, e.g., halogen lights, home appliances such a vacuum cleaners, and the like. Numerous appliances and computer equipment can be plugged in at any time, and those units can be turned on or off at any time, or operated for any amount of time. These types of changes throughout the day cause the powerline network transfer function to change almost constantly. When two powerline network nodes are involved in a communication, for example, a transmitting node is sending a frame over the powerline medium to a receiving node, a significant change in the powerline network transfer function occurring between the two nodes (e.g., when the receiving node suffers a loss of power or is unplugged) may mean that no response will be received from the receiving node for a frame that the transmitting network node attempts to transmit to that node over the powerline network under such conditions. If the powerline nodes implement the media access control protocol specified by the HomePlug 1.0 Specification, the transmitting node attempts several transmission "retries" using a more robust, reduced data rate transmission mode. During a "retry" period, the powerline bandwidth is reduced because of the transmission of the robust retry frames on the powerline. The reduced bandwidth causes congestion to occur at the transmitting node. Consequently, buffers may not be available in the transmitting node to store frames waiting to be transmitted to the receiving node and other nodes. Under these conditions, transmissions destined for other nodes, including nodes that are able to receive and respond to transmissions, are effectively blocked as well. In addition, if the transmitting node is a bridge that is still receiving frames from another network, it cannot empty its buffers until frame transmissions to the powerline network are completed. As a result, bridge congestion may cause back pressure to be exerted on that other network.

Powerline network flood control restriction


A RFID system applying to a three-dimensional jigsaw is provided. The RFID system includes a jigsaw substrate having a plurality of blocks, a plurality of jigsaw units corresponding to each blocks of the jigsaw substrate, a RFID reader having a plurality of antennas positioned in a position of each blocks of the jigsaw substrate, and a plurality of tags positioned in a position of each face of a three-dimensional jigsaw unit corresponding to the positions of the antennas, wherein the RFID reader communicates to the tags using modulated radio signals through the antennas and the tags respond with modulated radio signals in order to determine whether the orientation of the three-dimensional jigsaw unit is correct or not.

1. Field of Invention
The present invention relates to a radio frequency identification (RFID) reader using a plurality of antennas for reading data from Tags, and more particularly to a RFID reader using a plurality of antennas applied to multi-dimensional objects, such as three-dimensional jigsaw with multimedia sound and light effect, to distinguish the orientation of the three-dimensional jigsaw unit between right and wrong.
2. Description of Related Arts
Radio Frequency Identification (RFID) systems are used for identification and/or tracking of equipment, inventory, or living things. RFID systems are radio communication systems that communicate between a radio transceiver, called a RFID reader, and a number of inexpensive devices called Tags or transponders. In RFID systems, the RFID reader communicates to the Tags using modulated radio signals, and the Tags respond with modulated radio signals. Conventional RFID systems are designed a) to identify an object passing into range of the RFID reader, and b) to store data onto the Tag and then retrieve that data from the Tag at a later time in order to manage inventory or perform some other useful application. In this application, the transmit and receive antennas have the same bandwidth. In fact, transmit and receive frequently share the same antenna, using a circulator to separate the transmit and receive paths.
As described in the U.S. patent application Ser. No. 11/062,815, filed on Feb. 23, 2005, a radio frequency identification (RFID) reader comprising a plurality of antennas could be applied to multi-dimensional objects, such as three-dimensional jigsaw with multimedia sound and light effect, Monopoly board game, . . . etc. However, in this prior art each of antennas in the RFID reader is positioned in a central region of each plane of multi-dimensional objects such as three-dimensional jigsaw. In order for the RFID reader to sense the identifier, the polarizations of the electromagnetic fields generated by the antennas in the RFID reader and Tag must be aligned. In most real-world implementations, however, the orientation of the Tag, and, hence, the polarization of the field generated by the Tag's antenna, is unknown. Therefore, the RFID reader could not distinguish the orientation of the three-dimensional jigsaw unit between right and wrong because the modulated radio signals are non-direction signals. In other words, the RFID reader could not distinguish the orientation of the three-dimensional jigsaw unit between right and wrong even though the three-dimensional jigsaw unit aims at the right position. Therefore, there is a need in the art for a RFID reader that can read Tags and also distinguish the Tags' orientations.

Multi-dimensional antenna in RFID system for reading tags and orientating multi-dimensional objects


A power supply control device includes: a control board that is configured to control a voltage of a battery module; and a bus bar module that is configured to electrically connect the control board and the battery module, the control board and the bus bar module are arranged in a stacked manner, and connection terminals of the bus bar module which are connected to the battery module are exposed when viewed from the control board.

A battery system mounted on a hybrid vehicle or an electric vehicle includes a control board that detects a voltage of a battery so as to prevent degradation of the battery due to overcharge or the like. For example, as described in Patent Document 1, the control board is installed on a battery module including multiple batteries and is electrically connected to the several batteries.


The present disclosure relates to a mobile terminal and a voice recognition method thereof. The voice recognition method may include receiving a user's voice; providing the received voice to a first voice recognition engine provided in the server and a second voice recognition engine provided in the mobile terminal; acquiring first voice recognition data as a result of recognizing the received voice by the first voice recognition engine; acquiring second voice recognition data as a result of recognizing the received voice by the second voice recognition engine; estimating a function corresponding to the user's intention based on at least one of the first and the second voice recognition data; calculating a similarity between the first and the second voice recognition data when personal information is required for the estimated function; and selecting either one of the first and the second voice recognition data based on the calculated similarity.

1. Field of the Invention
The present disclosure relates to a mobile terminal, and more particularly, to a mobile terminal having a voice recognition function and a voice recognition method thereof.
2. Description of the Related Art
Terminals can be classified into mobile or portable terminals and a stationary terminals based on its mobility. Furthermore, the mobile terminals can be further classified into handheld terminals and vehicle mount terminals based on whether or not it can be directly carried by a user.
As it becomes multifunctional, for example, such a terminal is allowed to capture still images or moving images, play music or video files, play games, receive broadcast and the like, so as to be implemented as an integrated multimedia player. Moreover, the improvement of structural or software elements of the terminal may be taken into consideration to support and enhance the functions of the terminal.
For examples of the enhancement, a voice recognition function can be carried out using various algorithms in the mobile terminal. A lot of data computation amount and resources are required to implement a voice recognition function. Due to this, a distributed voice recognition system for realizing suitable resource distribution has been introduced. However, studies for enhancing the speediness and accuracy of its voice recognition result have been actively carried out even in such a distributed voice recognition system.

Mobile terminal and method for recognizing voice thereof


The invention relates to a method of determining a plaintext M on the basis of a cipher C and using a secret key d, wherein the secret key d is used in binary form, wherein the plaintext M is determined in each iteration step i for the corresponding bit di and a security variable Mn is determined in parallel therewith, and then a verification variable x is determined by means of a bit-compatible exponent of the secret key d.

Such methods are known for example by the RSA method. In the RSA method, a plaintext is encrypted by means of a public key, wherein this cipher can be decrypted again by means of an associated secret key. Since the encrypted data are usually highly confidential and nevertheless are publicly accessible, the data are more and more frequently being exposed to attacks in order to spy out the secret key so that the encrypted data can be decrypted and thus undesirably determined in order to misuse the decrypted data.
Such attacks have become known as timing attacks or differential fault analysis (DFA) attacks, in which the computation time or running time of a calculation or a fault behavior during manipulations is observed in order to determine the secret key that is used during such processes.
Therefore, methods have been created which, using considerable computational effort through an inverse RSA function or a second RSA calculation, attempt to ascertain such manipulations and make them ineffective.


A unitarily molded, snap-on heat shield for a standard automotive battery container having handle brackets extending from opposing side walls of the container, the heat shield having wedge-shaped coupling protrusions extending inwardly from cantilevered flaps in the heat shield side walls, the wedge-shaped protrusions riding along the handle brackets to cantilever the flaps away for the container side wall as the shield in moved downward over the container, the flaps snapping back inward toward the battery container as the protrusions pass the handle bracket to couple the heat shield to the battery container.

The underhood temperature of a motor vehicle can reach 200.degree. F. during operation, and even 230.degree. F. in extremely hot environmental conditions. Subjecting storage batteries to such excessive temperatures accelerates corrosion of the battery grids, which is a major factor in shortening of battery life. Consequently, the automotive industry has long recognized the need to protect the batteries in motor vehicles from the hot temperatures present in the engine compartment during operation.
Vehicle batteries are conventionally protected from underhood heating by the placement of an insulting shell or shield over the battery. Generally, the shield acts as an insulator. For example, U.S. Pat. No. 5,278,002 to Hiers discloses a box-like battery shield with attachable envelopes of plastic material containing insulation. The heat shield is coupled to the battery by a friction fit along the top and sides of the battery. U.S. Patent to Longardner et al. discloses the encapsulation of a battery with a phase change material. Alternately, the shield may be designed to provide an air gap between the sidewalls of the battery and the shield through which cooler outside air is circulated either by fan or as the result of vehicle motion.
Some insulating shells are designed to be mounted on the battery after it has been installed in the vehicle. For example, U.S. Pat. No. 5,086,860 to Francis et al. discloses a tray upon which the battery is disposed and over which a box placed. The box is secured to the tray by an L-shaped bracket, which extends over the top and one side of the box.
Other heat shields are designed to be assembled onto the battery prior to vehicle installation. It is generally recognized in the automotive industry that creating such a subassembly prior to the final assembly line can reduce overall costs.
For example, U.S. Pat. No. 5,212,025 to Osamu Shibata et al. discloses a storage battery for automobiles which includes a heat shield that is designed to be a part of the battery assembly, making it easier to mount the battery in an automobile. The heat shield is a box-like structure having a closed bottom and which is open at the top to permit the battery to be positioned within the heat shield. The arrangement requires a non-standard cover for the battery to define the air gap and a non-standard container to provide the latching recesses in its for securing the heat shield to the battery. Further, because the heat shield has a closed bottom, the battery must be lifted in order to position it within the heat shield. In addition, this arrangement requires modification of the battery hold down tray and hold down hardware.
U.S. Pat. No. 5,543,248 to Dougherty et al. discloses a clam shell type designs wherein front and rear section halves are coupled to a base by living hinges, or coupled to each other by living hinges. U.S. Pat. No. 5,536,595 to Inkmann et al. and U.S. Pat. No. 4,054,730 to Crifasi disclose a similar two part heat shields which slide onto the battery along its opposite sides to surround the four sides of the battery, the top and bottom being open. The halves are secured together by latches along opposite sides.
While such clam shell shields may be injection molded on a production scale, a number of disadvantages are associated with such clam shell designs. The battery must be assembled into the clamshell prior to assembly into the vehicle. Clamshell side latches are typically not robust enough to assure that shield will remain locked to the battery during installation into the vehicle. Additionally, it is difficult for one person to remove a clam shell heat shield. One person must hold the clamshell open while another removes the battery from the open shield. Further, clamshell designs do not generally lend themselves to easy manual or automated assembly. This results in excessive cost and/or effort to implement on a production basis. Also, clamshells do not typically cover the top of the battery. Covering the top of a battery, however, is critical in extreme operating conditions.


An economic parameter estimator is provided for a process that has multiple process parameters (MPPs) and is performed to control emission of a pollutant into the air. The performance of the process is associated with one or more economic factors (EFs). The estimator includes either a neural network process model or a non-neural network process model. In either case, the model represents a relationship between one or more of the MPPs and an economic parameter. Also included is a processor configured with logic, e.g. programmed software, to estimate a monetary value of the economic parameter based on a value of each of the one or more MPPs, a value of each of at least one of the one or more EFs, and the one model.

1. Field of Endeavor
The present invention relates generally to process control. More particularly the present invention relates to techniques for enhanced control of processes, such as those utilized for air pollution control. Examples of such processes include but are not limited to wet and dry flue gas desulfurization (WFGD/DFGD), nitrogen oxide removal via selective catalytic reduction (SCR), and particulate removal via electro-static precipitation (ESP).
2. Background
Wet Flue Gas Desulfurization:
As noted, there are several air pollution control processes, to form a basis for discussion; the WFGD process will be highlighted. The WFGD process is the most commonly used process for removal of SO2 from flue gas in the power industry. FIG. 1, is a block diagram depicting an overview of a wet flue gas desulfurization (WFGD) subsystem for removing SO2 from the dirty flue gas, such as that produced by fossil fuel, e.g. coal, fired power generation systems, and producing a commercial grade byproduct, such as one having attributes which will allow it to be disposed of at a minimized disposal cost, or one having attributes making it saleable for commercial use.
In the United States of America, the presently preferred byproduct of WFGD is commercial grade gypsum having a relatively high quality (95+% pure) suitable for use in wallboard, which is in turn used in home and office construction. Commercial grade gypsum of high quality (˜92%) is also the presently preferred byproduct of WFGD in the European Union and Asia, but is more typically produced for use in cement, and fertilizer. However, should there be a decline in the market for higher quality gypsum, the quality of the commercial grade gypsum produced as a byproduct of WFGD could be reduced to meet the less demanding quality specifications required for disposal of at minimum costs. In this regard, the cost of disposal may be minimized if, for example, the gypsum quality is suitable for either residential landfill or for backfilling areas from which the coal utilized in generating power has been harvested.
As shown in FIG. 1, dirty, SO2 laden flue gas 112 is exhausted from a boiler or economizer (not shown) of a coal fired power generation system 110 to the air pollution control system (APC) 120. Commonly the dirty flue gas 112 entering the APC 120 is not only laden with SO2, but also contains other so called pollutants such as NOx and particulate matter. Before being processed by the WFGD subsystem, the dirty flue gas 112 entering the APC 120 is first directed to other APC subsystems 122 in order remove NOx and particulate matter from the dirty flue gas 112. For example, the dirty flue gas may be processed via a selective catalytic reduction (SCR) subsystem (not shown) to remove NOx and via an electrostatic precipitator subsystem (EPS) (not shown) or filter (not shown) to remove particulate matter.
The SO2 laden flue gas 114 exhausted from the other APC subsystems 122 is directed to the WFGD subsystem 130. SO2 laden flue gas 114 is processed by the absorber tower 132. As will be understood by those skilled in the art, the SO2 in the flue gas 114 has a high acid concentration. Accordingly, the absorber tower 132 operates to place the SO2 laden flue gas 114 in contact with liquid slurry 148 having a higher pH level than that of the flue gas 114.
It will be recognized that most conventional WFGD subsystems include a WFGD processing unit of the type shown in FIG. 1. This is true, for many reasons. For example, as is well understood in the art, WFGD processing units having a spray absorber towers have certain desirable process characteristics for the WFGD process. However, WFGD processing units having other absorption/oxidation equipment configurations could, if desired, be utilized in lieu of that shown in FIG. 1 and still provide similar flue gas desulfurization functionality and achieve similar benefits from the advanced process control improvements presented in this application. For purposes of clarity and brevity, this discussion will reference the common spray tower depicted in FIG. 1, but it should be noted that the concepts presented could be applied to other WFGD configurations.
During processing in the countercurrent absorber tower 132, the SO2 in the flue gas 114 will react with the calcium carbonate-rich slurry (limestone and water) 148 to form calcium sulfite, which is basically a salt and thereby removing the SO2 from the flue gas 114. The SO2 cleaned flue gas 116 is exhausted from the absorber tower 132, either to an exhaust stack 117 or to down-steam processing equipment (not shown). The resulting transformed slurry 144 is directed to the crystallizer 134, where the salt is crystallized. The crystallizer 134 and the absorber 132 typically reside in a single tower with no physical separation between them—while there are different functions (absorption in the gas phase and crystallization in the liquid phase) going on, the two functions occur in the same process vessel. From here, gypsum slurry 146, which includes the crystallized salt, is directed from the crystallizer 134 to the dewatering unit 136. Additionally, recycle slurry 148, which may or may not include the same concentration of crystallized salts as the gypsum slurry 146, is directed from the crystallizer 134 through pumps 133 and back to the absorber tower 132 to continue absorption cycle.
The blower 150 pressurizes ambient air 152 to create oxidation air 154 for the crystallizer 134. The oxidation air 154 is mixed with the slurry in the crystallizer 134 to oxidize the calcium sulfite to calcium sulfate. Each molecule of calcium sulfate binds with two molecules of water to form a compound that is commonly referred to as gypsum 160. As shown, the gypsum 160 is removed from the WFGD processing unit 130 and sold to, for example manufacturers of construction grade wallboard.
Recovered water 167, from the dewatering unit 136 is directed to the mixer/pump 140 where it is combined with fresh ground limestone 174 from the grinder 170 to create limestone slurry. Since some process water is lost to both the gypsum 160 and the waste stream 169, additional fresh water 162, from a fresh water source 164, is added to maintain the limestone slurry density. Additionally, waste, such as ash, is removed from the WFGD processing unit 130 via waste stream 169. The waste could, for example, be directed to an ash pond or disposed of in another manner.
In summary, the SO2 within the SO2 laden flue gas 114 is absorbed by the slurry 148 in the slurry contacting area of the absorber tower 132, and then crystallized and oxidized in the crystallizer 134 and dewatered in the dewatering unit 136 to form the desired process byproduct, which in this example, is commercial grade gypsum 160. The SO2 laden flue gas 114 passes through the absorber tower 132 in a matter of seconds. The complete crystallization of the salt within the transformed slurry 144 by the crystallizer 134 may require from 8 hours to 20+ hours. Hence, the crystallizer 134 has a large volume that serves as a slurry reservoir crystallization. The recycle slurry 148 is pumped back to the top of the absorber to recover additional SO2.
As shown, the slurry 148 is fed to an upper portion of the absorber tower 132. The tower 132 typically incorporates multiple levels of spray nozzles to feed the slurry 148 into the tower 132. The absorber 132, is operated in a countercurrent configuration: the slurry spray flows downward in the absorber and comes into contact with the upward flowing SO2 laden flue gas 114 which has been fed to a lower portion of the absorber tower.
Fresh limestone 172, from limestone source 176, is first ground in the grinder 170 (typically a ball mill) and then mixed with (recovered water 167 and fresh/make-up water 162 in a mixer 140 to form limestone slurry 141. The flow of the ground limestone 174 and water 162 via valve (not shown) to the mixer/tank 140 are controlled to maintain a sufficient inventory of fresh limestone slurry 141 in the mixer/tank 140. The flow of fresh limestone slurry 141 to the crystallizer 134 is adjusted to maintain an appropriate pH for the slurry 148, which in turn controls the amount of SO2 removed from the flue gas 114. WFGD processing typically accomplishes 92-97% removal of SO2 from the flue gas, although those skilled in the art will recognize that but utilizing certain techniques and adding organic acids to the slurry the removal of SO2 can increase to greater than 97%.
As discussed above, conventional WFGD subsystems recycle the slurry. Although some waste water and other waste will typically be generated in the production of the gypsum, water is reclaimed to the extent possible and used to make up fresh limestone slurry, thereby minimizing waste and costs, which would be incurred to treat the process water.
It will be recognized that because limestone is readily available in large quantities in most locations, it is commonly used as the reactant in coal gas desulfurization processing. However, other reactants, such as quick lime or a sodium compound, could alternatively be used, in lieu of limestone. These other reactants are typically more expensive and are not currently cost-competitive with the limestone reactant. However, with very slight modifications to the mixer 140 and upstream reactant source, an existing limestone WFGD could be operated using quick lime or a sodium compound. In fact, most WFGD systems include a lime backup subsystem so the WFGD can be operated if there are problems with limestone delivery and/or extended maintenance issues with the grinder 170.
FIG. 2 further details certain aspects of the WFGD subsystem shown in FIG. 1. As shown, the dewatering unit 136 may include both a primary dewatering unit 136A and a secondary dewatering unit 136B. The primary dewatering unit 136A preferably includes hydrocyclones for separating the gypsum and water. The secondary dewatering unit 136B preferably includes a belt dryer for drying the gypsum. As has been previously discussed, the flue gas 114 enters the absorber 132, typically from the side, and flows upward through a limestone slurry mist that is sprayed into the upper portion of the absorber tower. Prior to exiting the absorber, the flue gas is put through a mist eliminator (ME) (not shown) that is located in the top of the absorber 132; the mist eliminator removes entrained liquid and solids from the flue gas stream. To keep the mist eliminator clean of solids, a ME water wash 200 applied to the mist eliminator. As will be understood, the ME wash 200 keeps the ME clean within the absorber tower 132 with water from the fresh water source 164. The ME wash water 200 is the purest water fed to the WFGD subsystem 130.
As noted above, the limestone slurry mist absorbs a large percentage of the SO2 (e.g., 92-97%) from the flue gas that is flowing through the absorber tower 132. After absorbing the SO2, the slurry spray drops to the crystallizer 134. In a practical implementation, the absorber tower 132 and the crystallizer 134 are often housed in a single unitary structure, with the absorber tower located directly above the crystallizer within the structure. In such implementations, the slurry spray simply drops to the bottom of the unitary structure to be crystallized.
The limestone slurry reacts with the SO2 to produce gypsum (calcium sulfate dehydrate) in the crystallizer 134. As previously noted, forced, compressed oxidation air 154 is used to aid in oxidation, which occurs in the following reaction:SO2+CaCO3+½O2+2H2O→CaSO4.2H2O+CO2  (1)The oxidation air 154 is forced into the crystallizer 134, by blower 150. Oxidation air provides additional oxygen needed for the conversion of the calcium sulfite to calcium sulfate.
The absorber tower 132 is used to accomplish the intimate flue gas/liquid slurry contact necessary to achieve the high removal efficiencies required by environmental specifications. Countercurrent open-spray absorber towers provide particularly desirable characteristics for limestone-gypsum WFGD processing: they are inherently reliable, have lower plugging potential than other tower-based WFGD processing unit components, induce low pressure drop, and are cost-effective from both a capital and an operating cost perspective.
As shown in FIG. 2, the water source 164 typically includes a water tank 164A for storing a sufficient quantity of fresh water. Also typically included there is one or more pumps 164B for pressurizing the ME wash 200 to the absorber tower 132, and one or more pumps 164C for pressurizing the fresh water flow 162 to the mixer 140. The mixer 140 includes a mixing tank 140A and one more slurry pumps 140B to move the fresh limestone slurry 141 to the crystallizer 134. One or more additional very large slurry pumps 133 (see FIG. 1) are required to lift the slurry 148 from the crystallizer 134 to the multiple spray levels in the top of the absorber tower 132.
As will be described further below, typically, the limestone slurry 148 enters the absorber tower 132, via spray nozzles (not shown) disposed at various levels of the absorber tower 132. When at full load, most WFGD subsystems operate with at least one spare slurry pump 133. At reduced loads, it is often possible to achieve the required SO2 removal efficiency with a reduced number of slurry pumps 133. There is significant economic incentive to reduce the pumping load of the slurry pumps 133. These pumps are some of the largest pumps in the world and they are driven by electricity that could otherwise be sold directly to the power grid (parasitic power load).
The gypsum 160 is separated from liquids in the gypsum slurry 146 in the primary dewaterer unit 136A, typically using a hydrocyclone. The overflow of the hydrocyclone, and/or one or more other components of primary dewaterer unit 136A, contains a small amount of solids. As shown in FIG. 2, this overflow slurry 146A is returned to the crystallizer 134. The recovered water 167 is sent back to mixer 140 to make fresh limestone slurry. The other waste 168 is commonly directed from the primary dewaterer unit 136A to an ash pond 210. The underflow slurry 202 is directed to the secondary dewaterer unit 136B, which often takes the form of a belt filter, where it is dried to produce the gypsum byproduct 160. Again, recovered water 167 from the secondary dewaterer unit 136B is returned to the mixer/pump 140. As shown in FIG. 1, hand or other gypsum samples 161 are taken and analyzed, typically every few hours, to determine the purity of the gypsum 160. No direct on-line measurement of gypsum purity is conventionally available.
As shown in FIG. 1, a proportional integral derivative (PID) controller 180 is conventionally utilized in conjunction with a feedforward controller (FF) 190 to control the operation of the WFDG subsystem. Historically, PID controllers directed pneumatic analog control functions. Today, PID controllers direct digital control functions, using mathematically formulations. The goal of FF 190/PID controller 180 is to control the slurry pH, based on an established linkage. For example, there could be an established linkage between the adjustment of valve 199 shown in FIG. 1, and a measured pH value of slurry 148 flowing from the crystallizer 134 to the absorber tower 132. If so, valve 199 is controlled so that the pH of the slurry 148 corresponds to a desired value 186, often referred to as a setpoint (SP).
The FF 190/PID controller 180 will adjust the flow of the limestone slurry 141 through valve 199, based on the pH setpoint, to increase or decrease the pH value of the slurry 148 measured by the pH sensor 182. As will be understood, this is accomplish by the FF/PID controller transmitting respective control signals 181 and 191, which result in a valve adjustment instruction, shown as flow control SP 196, to a flow controller which preferably is part of the valve 199. Responsive to flow control SP 196, the flow controller in turn directs an adjustment of the valve 199 to modify the flow of the limestone slurry 141 from the mixer/pump 140 to the crystallizer 134.
The present example shows pH control using the combination of the FF controller 190 and the PID controller 180. Some installations will not include the FF controller 190.
In the present example, the PID controller 180 generates the PID control signal 181 by processing the measured slurry pH value 183 received from the pH sensor 182, in accordance with a limestone flow control algorithm representing an established linkage between the measured pH value 183 of the slurry 148 flowing from the crystallizer 134 to the absorber tower 132. The algorithm is typically stored at the PID controller 180, although this is not mandatory. The control signal 181 may represent, for example, a valve setpoint (VSP) for the valve 199 or for a measured value setpoint (MVSP) for the flow of the ground limestone slurry 141 exiting the valve 199.
As is well understood in the art, the algorithm used by the PID controller 180 has a proportional element, an integral element, and a derivative element. The PID controller 180 first calculates the difference between the desired SP and the measured value, to determine an error. The PID controller next applies the error to the proportional element of the algorithm, which is an adjustable constant for the PID controller, or for each of the PID controllers if multiple PID controllers are used in the WFGD subsystem. The PID controller typically multiples a tuning factor or process gain by the error to obtain a proportional function for adjustment of the valve 199.
However, if the PID controller 180 does not have the correct value for the tuning factor or process gain, or if the process conditions are changing, the proportional function will be imprecise. Because of this imprecision, the VSP or MVSP generated by the PID controller 180 will actually have an offset from that corresponding to the desired SP. Accordingly, the PID controller 180 applies the accumulated error over time using the integral element. The integral element is a time factor. Here again, the PID controller 180 multiplies a tuning factor or process gain by the accumulated error to eliminate the offset.
Turning now to the derivative element. The derivative element is an acceleration factor, associated with continuing change. In practice, the derivative element is rarely applied in PID controllers used for controlling WFGD processes. This is because application of the derivative element is not particularly beneficial for this type of control application. Thus, most controllers used for in WFGD subsystems are actually PI controllers. However, those skilled in the art will recognize that, if desired, the PID controller 180 could be easily configured with the necessary logic to apply a derivative element in a conventional manner.
In summary, there are three tuning constants, which may be applied by conventional PID controllers to control a process value, such as the pH of the recycle slurry 148 entering the absorber tower 132, to a setpoint, such as the flow of fresh lime stone slurry 141 to the crystallizer 134. Whatever setpoint is utilized, it is always established in terms of the process value, not in terms of a desired result, such as a value of SO2 remaining in the flue gas 116 exhausted from the absorber tower 132. Stated another way, the setpoint is identified in process terms, and it is necessary that the controlled process value be directly measurable in order for the PID controller to be able to control it. While the exact form of the algorithm may change from one equipment vendor to another, the basic PID control algorithm has been in use in the process industries for well over 75 years.
Referring again to FIGS. 1 and 2, based on the received instruction from the PID controller 180 and the FF controller 190, the flow controller generates a signal, which causes the valve 199 to open or close, thereby increasing or decreasing the flow of the ground limestone slurry 141. The flow controller continues control of the valve adjustment until the valve 199 has been opened or closed to match the VSP or the measured value of the amount of limestone slurry 141 flowing to from the valve 1992 matches the MVSP.
In the exemplary conventional WFGD control described above, the pH of the slurry 148 is controlled based on a desired pH setpoint 186. To perform the control, the PID 180 receives a process value, i.e. the measured value of the pH 183 of the slurry 148, from the sensor 182. The PID controller 180 processes the process value to generate instructions 181 to the valve 199 to adjust the flow of fresh limestone slurry 141, which has a higher pH than the crystallizer slurry 144, from the mixer/tank 140, and thereby adjust the pH of the slurry 148. If the instructions 181 result in a further opening of the valve 199, more limestone slurry 141 will flow from the mixer 140 and into the crystallizer 134, resulting in an increase in the pH of the slurry 148. On the other hand, if the instructions 181 result in a closing of the valve 199, less limestone slurry 141 will flow from the mixer 140 and therefore into the crystallizer 134, resulting in a decrease in the pH of the slurry 148.
Additionally, the WFGD subsystem may incorporate a feed forward loop, which is implemented using a feed forward unit 190 in order to ensure stable operation. As shown in FIG. 1, the concentration value of SO2 189 in the flue gas 114 entering the absorber tower 132 is measured by sensor 188 and input to the feed forward unit 190. Many WFGD systems that include the FF control element may combine the incoming flue gas SO2 concentration 189 with a measure of generator load from the Power Generation System 110, to determine the quantity of inlet SO2 rather than just the concentration and, then use this quantity of inlet SO2 as the input to FF 190. The feed forward unit 190 serves as a proportional element with a time delay.
In the exemplary implementation under discussion, the feed forward unit 190 receives a sequence of SO2 measurements 189 from the sensor 188. The feed forward unit 190 compares the currently received concentration value with the concentration value received immediately preceding the currently received value. If the feed forward unit 190 determines that a change in the measured concentrations of SO2 has occurred, for example from 1000-1200 parts per million, it is configured with the logic to smooth the step function, thereby avoiding an abrupt change in operations.
The feed forward loop dramatically improves the stability of normal operations because the relationship between the pH value of the slurry 148 and the amount of limestone slurry 141 flowing to the crystallizer 134 is highly nonlinear, and the PID controller 180 is effectively a linear controller. Thus, without the feed forward loop, it is very difficult for the PID 180 to provide adequate control over a wide range of pH with the same tuning constants.
By controlling the pH of the slurry 148, the PID controller 180 effects both the removal of SO2 from the SO2 laden flue gas 114 and the quality of the gypsum byproduct 160 produced by the WFGD subsystem. Increasing the slurry pH by increasing the flow of fresh limestone slurry 141 increases the amount of SO2 removed from the SO2 laden flue gas 114. On the other hand, increasing the flow of limestone slurry 141, and thus the pH of the slurry 148, slows the SO2 oxidation after absorption, and thus the transformation of the calcium sulfite to sulfate, which in turn will result in a lower quality of gypsum 160 being produced.
Thus, there are conflicting control objectives of removing SO2 from the SO2 laden flue gas 114, and maintaining the required quality of the gypsum byproduct 160. That is, there may be a conflict between meeting the SO2 emission requirements and the gypsum quality requirements.
FIG. 3 details further aspects of the WFGD subsystem described with reference to FIGS. 1 and 2. As shown, SO2 laden flue gas 114 enters into a bottom portion of the absorber tower 132 via an aperture 310, and SO2 free flue gas 116 exits from an upper portion of the absorber tower 132 via an aperture 312. In this exemplary conventional implementation, a counter current absorber tower is shown, with multiple slurry spray levels. As shown, the ME wash 200 enters the absorber tower 132 and is dispersed by wash sprayers (not shown).
Also shown are multiple absorber tower slurry nozzles 306A, 306B and 306C, each having a slurry sprayer 308A, 308B or 308C, which sprays slurry into the flue gas to absorb the SO2. The slurry 148 is pumped from the crystallizer 134 shown in FIG. 1, by multiple pumps 133A, 133B and 133C, each of which pumps the slurry up to a different one of the levels of slurry nozzles 306A, 306B or 306C. It should be understood that although 3 different levels of slurry nozzles and sprayers are shown, the number of nozzles and sprayers would vary depending on the particular implementation.
A ratio of the flow rate of the liquid slurry 148 entering the absorber 132 over the flow rate of the flue gas 116 leaving the absorber 132 is commonly characterized as the L/G. L/G is one of the key design parameters in WFGD subsystems.
The flow rate of the flue gas 116 (saturated with vapor), designated as G, is a function of inlet flue gas 112 from the power generation system 110 upstream of the WFGD processing unit 130. Thus, G is not, and cannot be, controlled, but must be addressed, in the WFGD processing. So, to impact L/G, the "L" must be adjusted. Adjusting the number of slurry pumps in operation and the "line-up" of these slurry pumps controls the flow rate of the liquid slurry 148 to the WFGD absorber tower 132, designated as L. For example, if only two pumps will be run, running the pumps to the upper two sprayer levels vs. the pumps to top and bottom sprayer levels will create different "L"s.
It is possible to adjust "L" by controlling the operation of the slurry pumps 133A, 133B and 133C. Individual pumps may be turned on or off to adjust the flow rate of the liquid slurry 148 to the absorber tower 132 and the effective height at which the liquid slurry 148 is introduced to the absorber tower. The higher the slurry is introduced into the tower, the more contact time it has with the flue gas resulting in more SO2 removal, but this additional SO2 removal comes at the penalty of increased power consumption to pump the slurry to the higher spray level. It will be recognized that the greater the number of pumps, the greater the granularity of such control.
Pumps 133A-133C, which are extremely large pieces of rotating equipment, can be started and stopped automatically or manually. Most often, in the USA, these pumps are controlled manually by the subsystem operator. It is more common to automate starting/stopping rotating equipment, such as pumps 133A-133C in Europe.
If the flow rate of the flue gas 114 entering the WFGD processing unit 130 is modified due to a change in the operation of the power generation system 110, the WFGD subsystem operator may adjust the operation of one or more of the pumps 133A-133C. For example, if the flue gas flow rate were to fall to 50% of the design load, the operator, or special logic in the control system, might shut down one or more of the pumps that pump slurry to the spray level nozzles at one or more spray level.
Although not shown in FIG. 3, it will be recognized that extra spray levels, with associated pumps and slurry nozzles, are often provided for use during maintenance of another pump, or other slurry nozzles and/or slurry sprayers associated with the primary spray levels. The addition of this extra spray level adds to the capital costs of the absorber tower and hence the subsystem. Accordingly, some WFGD owners will decide to eliminate the extra spray level and to avoid this added capital costs, and instead add organic acids to the slurry to enhance its ability to absorb and therefore remove SO2 from the flue gas during such maintenance periods. However, these additives tend to be expensive and therefore their use will result in increased operational costs, which may, over time, offset the savings in capital costs.
As indicated in Equation 1 above, to absorb SO2, a chemical reaction must occur between the SO2 in the flue gas and the limestone in the slurry. The result of the chemical reaction in the absorber is the formation of calcium sulfite. In the crystallizer 134, the calcium sulfite is oxidized to form calcium sulfate (gypsum). During this chemical reaction, oxygen is consumed. To provide sufficient oxygen and enhance the speed of the reaction, additional O2 is added by blowing compressed air 154 into the liquid slurry in the crystallizer 134.
More particularly, as shown in FIG. 1 ambient air 152 is compressed to form compressed air 154, and forced into the crystallizer 134 by a blower, e.g. fan, 150 in order to oxidize the calcium sulfite in the recycle slurry 148 which is returned from the crystallizer 134 to the absorber 132 and the gypsum slurry 146 sent to the dewatering system 136 for further processing. To facilitate adjustment of the flow of oxidation air 154, the blower 150 may have a speed or load control mechanism.
Preferably, the slurry in the crystallizer 134 has excess oxygen. However, there is an upper limit to the amount of oxygen that can be absorbed or held by slurry. If the O2 level within the slurry becomes too low, the chemical oxidation of CaSO3 to CaSO4 in the slurry will cease. When this occurs, it is commonly referred to as limestone blinding. Once limestone blinding occurs, limestone stops dissolving into the slurry solution and SO2 removal can be dramatically reduced. The presence of trace amounts of some minerals can also dramatically slow the oxidation of calcium sulfite and/or limestone dissolution to create limestone blinding.
Because the amount of O2 that is dissolved in the slurry is not a measurable parameter, slurry can become starved for O2 in conventional WFGD subsystems if proper precautions are not taken. This is especially true during the summer months when the higher ambient air temperature lowers the density of the ambient air 152 and reduces the amount of oxidation air 154 that can be forced into the crystallizer 134 by the blower 150 at maximum speed or load. Additionally, if the amount of SO2 removed from the flue gas flow increases significantly, a corresponding amount of additional O2 is required to oxidize the SO2. Thus, the slurry can effectively become starved for O2 because of an increase in the flow of SO2 to the WFGD processing unit.
It is necessary to inject compressed air 154 that is sufficient, within design ratios, to oxidize the absorbed SO2. If it is possible to adjust blower 150 speed or load, and turning down the blower 150 at lower SO2 loads and/or during cooler ambient air temperature periods is desirable because it saves energy. When the blower 150 reaches maximum load, or all the O2 of a non-adjustable blower 150 is being utilized, it is not possible to oxidize an incremental increase in SO2. At peak load, or without a blower 150 speed control that accurately tracks SO2 removal, it is possible to create an O2 shortage in the crystallizer 134.
However, because it is not possible to measure the O2 in the slurry, the level of O2 in the slurry is not used as a constraint on conventional WFGD subsystem operations. Thus, there is no way of accurately monitoring when the slurry within the crystallizer 134 is becoming starved for O2. Accordingly, operators, at best, will assume that the slurry is becoming starved for O2 if there is a noticeable decrease in the quality of the gypsum by-product 160, and use their best judgment to control the speed or load of blower 150 and/or decrease SO2 absorption efficiency to balance the O2 being forced into the slurry, with the absorbed SO2 that must be oxidized. Hence, in conventional WFGD subsystems balancing of the O2 being forced into the slurry with the SO2 required to be absorbed from the flue gas is based, at best, on operator judgment.
In summary, conventional control of large WFGD subsystems for utility application is normally carried out within a distributed control system (DCS) and generally consists of on-off control logic as well as FF/PID feedback control loops. The parameters controlled are limited to the slurry pH level, the L/G ratio and the flow of forced oxidation air.
The pH must be kept within a certain range to ensure high solubility of SO2 (i.e. SO2 removal efficiency) high quality (purity) gypsum, and prevention of scale buildup. The operating pH range is a function of equipment and operating conditions. The pH is controlled by adjusting the flow of fresh limestone slurry 141 to the crystallizer 134. The limestone slurry flow adjustment is based on the measured pH of the slurry detected by a sensor. In a typically implementation, a PID controller and, optionally, FF controller included in the DCS are cascaded to a limestone slurry flow controller. The standard/default PID algorithm is used for pH control application.
The liquid-to-gas ratio (L/G) is the ratio of the liquid slurry 148 flowing to the absorber tower 132 to the flue gas flow 114. For a given set of subsystem variables, a minimum L/G ratio is required to achieve the desired SO2 absorption, based on the solubility of SO2 in the liquid slurry 148. The L/G ratio changes either when the flue gas 114 flow changes, or when the liquid slurry 148 flow changes, which typically occurs when slurry pumps 133 are turned on or off.
The oxidation of calcium sulfite to form calcium sulfate, i.e. gypsum, is enhanced by forced oxidation, with additional oxygen in the reaction tank of the crystallizer 134. Additional oxygen is introduced by blowing air into the slurry solution in the crystallizer 134. With insufficient oxidation, sulfite—limestone blinding can occur resulting in poor gypsum quality, and potentially subsequent lower SO2 removal efficiency, and a high chemical oxygen demand (COD) in the waste water.
The conventional WFGD process control scheme is comprised of standard control blocks with independent rather than integrated objectives. Currently, the operator, in consultation with the engineering staff, must try to provide overall optimal control of the process. To provide such control, the operator must take the various goals and constraints into account.
Minimized WFGD Operation Costs—Power plants are operated for no other reason than to generate profits for their owners. Thus, it is beneficial to operate the WFGD subsystem at the lowest appropriate cost, while respecting the process, regulatory and byproduct quality constraints and the business environment.
Maximize SO2 Removal Efficiency—Clean air regulations establish SO2 removal requirements. WFGD subsystems should be operated to remove SO2 as efficiently as appropriate, in view of the process, regulatory and byproduct quality constraints and the business environment.
Meet Gypsum Quality Specification—The sale of gypsum as a byproduct mitigates WFGD operating costs and depends heavily on the byproduct purity meeting a desired specification. WFGD subsystems should be operated to produce a gypsum byproduct of an appropriate quality, in view of the process, regulatory and byproduct quality constraints and the business environment.
Prevent Limestone Blinding—Load fluctuations and variations in fuel sulfur content can cause excursions in SO2 in the flue gas 114. Without proper compensating adjustments, this can lead to high sulfite concentrations in the slurry, which in turn results in limestone blinding, lower absorber tower 132 SO2 removal efficiency, poor gypsum quality, and a high chemical oxygen demand (COD) in the wastewater. WFGD subsystems should be operated to prevent limestone binding, in view of the process constraints.
In a typical operational sequence, the WFGD subsystem operator determines setpoints for the WFGD process to balance these competing goals and constraints, based upon conventional operating procedures and knowledge of the WFGD process. The setpoints commonly include pH, and the operational state of the slurry pumps 133 and oxidation air blower 150.
There are complex interactions and dynamics in the WFGD process; as a result, the operator selects conservative operating parameters so that the WFGD subsystem is able to meet/exceed hard constraints on SO2 removal and gypsum purity. In making these conservative selections, the operator often, if not always, sacrifices minimum-cost operation.
For example, FIG. 4 shows SO2 removal efficiency and gypsum purity as a function of pH. As pH is increased, the SO2 removal efficiency increases, however, the gypsum purity decreases. Since the operator is interested in improving both SO2 removal efficiency and gypsum purity, the operator must determine a setpoint for the pH that is a compromise between these competing goals.
In addition, in most cases, the operator is required to meet a guaranteed gypsum purity level, such as 95% purity. Because of the complexity of the relationships shown in FIG. 4, the lack of direct on-line measurement of gypsum purity, the long time dynamics of gypsum crystallization, and random variations in operations, the operator often chooses to enter a setpoint for pH that will guarantee that the gypsum purity level is higher than the specified constraint under any circumstances. However, by guaranteeing the gypsum purity, the operator often sacrifices the SO2 removal efficiency. For instance, based upon the graph in FIG. 4, the operator may select a pH of 5.4 to guarantee of 1% cushion above the gypsum purity constraint of 95%. However, by selecting this setpoint for pH, the operator sacrifices 3% of the SO2 removal efficiency.
The operator faces similar compromises when SO2 load, i.e. the flue gas 114 flow, drops from full to medium. At some point during this transition, it may be beneficial to shut off one or more slurry pumps 133 to save energy, since continued operation of the pump may provide only slightly better SO2 removal efficiency. However, because the relationship between the power costs and SO2 removal efficiency is not well understood by most operators, operators will typically take a conservative approach. Using such an approach, the operators might not adjust the slurry pump 133 line-up, even though it would be more beneficial to turn one or more of the slurry pumps 133 off.
It is also well known that many regulatory emission permits provide for both instantaneous emission limits and some form of rolling-average emission limits. The rolling-average emission limit is an average of the instantaneous emissions value over some moving, or rolling, time-window. The time-window may be as short as 1-hour or as long as 1-year. Some typical time-windows are 1-hour, 3-hours, 8-hours, 24-hours, 1-month, and 1-year. To allow for dynamic process excursions, the instantaneous emission limit is typically higher than rolling average limit. However, continuous operation at the instantaneous emission limit will result in a violation of the rolling-average limit.
Conventionally, the PID 180 controls emissions to the instantaneous limit, which is relatively simple. To do this, the operating constraint for the process, i.e. the instantaneous value, is set well within the actual regulatory emission limit, thereby providing a safety margin.
On the other hand, controlling emissions to the rolling-average limit is more complex. The time-window for the rolling-average is continually moving forward. Therefore, at any given time, several time-windows are active, spanning one time window from the given time back over a period of time, and another time window spanning from the given time forward over a period of time.
Conventionally, the operator attempts to control emissions to the rolling-average limit, by either simply maintaining a sufficient margin between the operating constraint set in the PID 180 for the instantaneous limit and the actual regulatory emission limit, or by using operator judgment to set the operating constraint in view of the rolling-average limit. In either case, there is no explicit control of the rolling-average emissions, and therefore no way to ensure compliance with the rolling-average limit or prevent costly over-compliance.
Selective Catalytic Reduction System:
Briefly turning to another exemplary air pollution control process, the selective catalytic reduction (SCR) system for NOx removal, similar operating challenges can be identified. An overview of the SCR process is shown in FIG. 20.
The following process overview is from "Control of Nitrogen Oxide Emissions: Selective Catalytic Reduction (SCR)", Topical Report Number 9, Clean Coal Technology, U.S. Dept. of Energy, 1997:
Process Overview
NOx, which consists primarily of NO with lesser amounts of NO2, is converted to nitrogen by reaction with NH3 over a catalyst in the presence of oxygen. A small fraction of the SO2, produced in the boiler by oxidation of sulfur in the coal, is oxidized to sulfur trioxide (SO3) over the SCR catalyst. In addition, side reactions may produce undesirable by-products: ammonium sulfate, (NH4)2SO4, and ammonium bisulfate, NH4HSO4. There are complex relationships governing the formation of these by-products, but they can be minimized by appropriate control of process conditions.
Ammonia Slip
Unreacted NH3 in the flue gas downstream of the SCR reactor is referred to as NH3 slip. It is essential to hold NH3 slip to below 5 ppm, preferably 2-3 ppm, to minimize formation of (NH4)2SO4 and NH4HSO4, which can cause plugging and corrosion of downstream equipment. This is a greater problem with high-sulfur coals, caused by higher SO3 levels resulting from both higher initial SO3 levels due to fuel sulfur content and oxidation of SO2 in the SCR reactor.
Operating Temperature
Catalyst cost constitutes 15-20% of the capital cost of an SCR unit; therefore it is essential to operate at as high a temperature as possible to maximize space velocity and thus minimize catalyst volume. At the same time, it is necessary to minimize the rate of oxidation of SO2 to SO3, which is more temperature sensitive than the SCR reaction. The optimum operating temperature for the SCR process using titanium and vanadium oxide catalysts is about 650-750° F. Most installations use an economizer bypass to provide flue gas to the reactors at the desired temperature during periods when flue gas temperatures are low, such as low load operation.
Catalysts
SCR catalysts are made of a ceramic material that is a mixture of carrier (titanium oxide) and active components (oxides of vanadium and, in some cases, tungsten). The two leading shapes of SCR catalyst used today are honeycomb and plate. The honeycomb form usually is an extruded ceramic with the catalyst either incorporated throughout the structure (homogeneous) or coated on the substrate. In the plate geometry, the support material is generally coated with catalyst. When processing flue gas containing dust, the reactors are typically vertical, with downflow of flue gas. The catalyst is typically arranged in a series of two to four beds, or layers. For better catalyst utilization, it is common to use three or four layers, with provisions for an additional layer, which is not initially installed.
As the catalyst activity declines, additional catalyst is installed in the available spaces in the reactor. As deactivation continues, the catalyst is replaced on a rotating basis, one layer at a time, starting with the top. This strategy results in maximum catalyst utilization. The catalyst is subjected to periodic soot blowing to remove deposits, using steam as the cleaning agent.
Chemistry:
The chemistry of the SCR process is given by the following:4NO+4NH3+O2→4N2+6H2O2NO2+4NH3+O2→3N2+6H2O
The side reactions are given by:SO2+½O2→SO3 2NH3+SO3+H2O→(NH4)2SO4 NH3+SO3+H2O→NH4HSO4 Process Description
As shown in FIG. 20, dirty flue gas 112 leaves the power generation system 110. This flue gas may be treated by other air pollution control (APC) subsystems 122 prior to entering the selective catalytic reduction (SCR) subsystem 2170. The flue gas may also be treated by other APC subsystems (not shown) after leaving the SCR and prior to exiting the stack 117. NOx in the inlet flue gas is measured with one or more analyzers 2003. The flue gas with NOx 2008 is passed through the ammonia (NH3) injection grid 2050. Ammonia 2061 is mixed with dilution air 2081 by an ammonia/dilution air mixer 2070. The mixture 2071 is dosed into the flue gas by the injection grid 2050. A dilution air blower 2080 supplies ambient air 152 to the mixer 2070, and an ammonia storage and supply subsystem 2060 supplies the ammonia to the mixer 2070. The NOx laden flue gas, ammonia and dilution air 2055 pass into the SCR reactor 2002 and over the SCR catalyst. The SCR catalyst promotes the reduction of NOx with ammonia to nitrogen and water. NOx "free" flue gas 2008 leaves the SCR reactor 2002 and exits the plant via potentially other APC subsystems (not shown) and the stack 117.
There are additional NOx analyzers 2004 on the NOx "free" flue gas stream 2008 exiting the SCR reactor 2002 or in the stack 117. The measured NOx outlet value 2111 is combined with the measured NOx inlet value 2112 to calculate a NOx removal efficiency 2110. NOx removal efficiency is defined as the percentage of inlet NOx removed from the flue gas.
The calculated NOx removal efficiency 2022 is input to the regulatory control system that resets the ammonia flow rate setpoint 2021A to the ammonia/dilution air mixer 2070 and ultimately, the ammonia injection grid 2050.
SCR Process Controls
A conventional SCR control system relies on the cascaded control system shown in FIG. 20. The inner PID controller loop 2010 is used for controlling the ammonia flow 2014 into the mixer 2070. The outer PID controller loop 2020 is used for controlling NOx emissions. The operator is responsible for entering the NOx emission removal efficiency target 2031 into the outer loop 2020. As shown in FIG. 21, a selector 2030 may be used to place an upper constraint 2032 on the target 2031 entered by the operator. In addition, a feedforward signal 2221 for load (not shown in FIG. 21) is often used so that the controller can adequately handle load transitions. For such implementations, a load sensor 2009 produces a measured load 2809 of the power generation system 110. This measured load 2809 is sent to a controller 2220 which produces the signal 2221. Signal 2221 is combined with the ammonia flow setpoint 2021A to form an adjusted ammonia flow setpoint 2021B, which is sent to PID controller 2010. PID 2010 combines setpoint 2021B with a measured ammonia flow 2012 to form an ammonia flow VP 2011 which controls the amount of ammonia supplied to mixer 2070.
The advantages of this controller are that:                1. Standard Controller: It is a simple standard controller design that is used to enforce requirements specified by the SCR manufacturer and catalyst vendor.        2. DCS-Based Controller: The structure is relatively simple, it can be implemented in the unit's DCS and it is the least-expensive control option that will enforce equipment and catalyst operating requirements.SCR Operating Challenges:
A number of operating parameters affect SCR operation:
Inlet NOx load,
Local molar ratio of NOx:ammonia,
Flue gas temperature, and
Catalyst quality, availability, and activity.
The operational challenges associated with the control scheme of FIG. 20 include the following:                1. Ammonia Slip Measurement: Maintaining ammonia slip below a specified constraint is critical to operation of the SCR. However, there is often no calculation or on-line measurement of ammonia slip. Even if an ammonia slip measurement is available, it is often not included directly in the control loop. Thus, one of the most critical variables for operation of an SCR is not measured.                    The operating objective for the SCR is to attain the desired level of NOx removal with minimal ammonia "slip". Ammonia "slip" is defined as the amount of unreacted ammonia in the NOx "free" flue gas stream. While there is little economic cost associated with the actual quantity of ammonia in the ammonia slip, there are significant negative impacts of ammonia slip:                            Ammonia can react with SO3 in the flue gas to form a salt, which deposited on the heat-transfer surfaces of the air preheater. Not only does this salt reduce the heat-transfer across the air preheater it also attracts ash that further reduces the heat-transfer. At a certain point, the heat-transfer of the air preheater has been reduced to the point where the preheater must be removed from service for cleaning (washing). At a minimum, air preheater washing creates a unit de-rate event.                Ammonia is also absorbed in the catalyst (the catalyst can be considered an ammonia sponge). Abrupt decreases in the flue gas/NOx load can result in abnormally high short-term ammonia slip. This is just a transient condition—outside the scope of the typical control system. While transient in nature, this slipped ammonia still combines with SO3 and the salt deposited on the air preheater—even though short-lived, the dynamic transient can significantly build the salt layer on the air preheater (and promote attraction of fly ash).                Ammonia is also defined as an air pollutant. While ammonia slip is very low, ammonia is very aromatic, so even relatively trace amounts can create an odor problem with the local community.                Ammonia is absorbed onto the fly ash. If the ammonia concentration of the fly ash becomes too great there can be a significant expensive associated with disposal of the fly ash.                                                2. NOx Removal Efficiency Setpoint: Without an ammonia slip measurement, the NOx removal efficiency setpoint 2031 is often conservatively set by the operator/engineering staff to maintain the ammonia slip well below the slip constraint. By conservatively selecting a setpoint for NOx, the operator/engineer reduces the overall removal efficiency of the SCR. The conservative setpoint for NOx removal efficiency may guarantee that an ammonia slip constraint is not violated but it also results in an efficiency that is lower than would be possible if the system were operated near the ammonia slip constraint.        3. Temperature Effects on the SCR: With the standard control system, no attempt is evident to control SCR inlet gas temperature. Normally some method of ensuring gas temperature is within acceptable limits is implemented, usually preventing ammonia injection if the temperature is below a minimum limit. No attempt to actually control or optimize temperature is made in most cases. Furthermore, no changes to the NOx setpoint are made based upon temperature nor based upon temperature profile.        4. NOx and Velocity Profile: Boiler operations and ductwork contribute to create non-uniform distribution of NOx across the face of the SCR. For minimal ammonia slip, the NOx:ammonia ratio must be controlled and without uniform mixing, this control must be local to avoid spots of high ammonia slip. Unfortunately, the NOx distribution profile is a function of not just the ductwork, but also boiler operation. So, changes in boiler operation impact the NOx distribution. Standard controllers do not account for the fact that the NOx inlet and velocity profiles to the SCR are seldom uniform or static. This results in over injection of reagent in some portions of the duct cross section in order to ensure adequate reagent in other areas. The result is increased ammonia slip for a given NOx removal efficiency. Again, the operator/engineer staff often responds to mal-distribution by lowering the NOx setpoint.                    It should be understood that the NOx inlet and outlet analyzers 2003 and 2004 may be a single analyzer or some form of an analysis array. In addition to the average NOx concentration, a plurality of analysis values would provide information about the NOx distribution/profile. To take advantage of the additional NOx distribution information, it would require a plurality of ammonia flow controllers 2010 with some intelligence to dynamically distribute the total ammonia flow among different regions of the injection grid so that the ammonia flow more closely matches the local NOx concentration.                        5. Dynamic Control: The standard controller also fails to provide effective dynamic control. That is, when the inlet conditions to the SCR are changing thus requiring modulation of the ammonia injection rate, it is unlikely that the feedback control of NOx reduction efficiency will be able to prevent significant excursions in this process variable. Rapid load transients and process time delays are dynamic events, which can cause significant process excursions.        6. Catalyst Decay: The catalyst decays over time reducing the removal efficiency of the SCR and increasing the ammonia slip. The control system needs to take this degradation into account in order to maximize NOx removal rate.        7. Rolling Average Emissions: Many regulatory emission permits provide for both instantaneous and some form of rolling-average emission limits. To allow for dynamic process excursions, the instantaneous emission limit is higher than rolling average limit; continuous operation at the instantaneous emission limit would result in violation of the rolling-average limit. The rolling-average emission limit is an average of the instantaneous emissions value over some moving, or rolling, time-window. The time-window may be as short at 1-hour or as long a 1-year. Some typical time-windows are 1-hour, 3-hours, 24-hours, 1-month, and 1-year. Automatic control of the rolling averages is not considered in the standard controller. Most NOx emission permits are tied back to the regional 8-hour rolling average ambient air NOx concentration limits.
Operators typically set a desired NOx removal efficiency setpoint 2031 for the SCR and make minor adjustments based on infrequent sample information from the fly ash. There is little effort applied to improving dynamic control of the SCR during load transients or to optimizing operation of the SCR. Selecting the optimal instantaneous, and if possible, rolling-average NOx removal efficiency is also an elusive and changing problem due to business, regulatory/credit, and process issues that are similar to those associated with optimal operation of the WFGD.
Other APC processes exhibit problems associated with:                Controlling/optimizing dynamic operation of the process,        Control of byproduct/co-product quality,        Control of rolling-average emissions, and        Optimization of the APC asset.
These problems in other processes are similar to that detailed in the above discussions of the WFGD and the SCR.

Estimating an economic parameter related to a process for controlling emission of a pollutant into the air


A method, article of manufacture, and apparatus for processing a first screen pointer and a second screen pointer in a viewable screen area, where the first screen pointer moves in response to user activity. A determination is made as to whether the first screen pointer moves within a predetermined distance of the second screen pointer. If the first screen pointer moves within the predetermined distance of the second screen pointer, at least one of the first screen pointer and the second screen pointer is altered to prevent the second screen pointer from obstructing the first screen pointer.

1. Field of the Invention
The invention relates to computers and computer software. More particularly, the invention relates to a method, article of manufacture and apparatus for processing screen pointers in a viewable screen area of a display.
2. Background of the Related Art
Computer systems typically execute a window display program to implement a window environment within a viewable screen area. The window display program generally utilizes screen pointers to indicate user activity in the window environment. Such screen pointers include text cursors and mouse cursors. A text cursor indicates the position in an active window within the viewable screen area in response to user activity, e.g., typing. A mouse cursor similarly indicates the position within the viewable area in response to user activity, e.g., movement of a mouse or input device.
However, a problem arises when the mouse obstructs the text cursor or vice versa, i.e., the text cursor obstructs the mouse cursor. Consider the situation where both the mouse cursor and the text cursor are positioned in the active window. If the user activity is typing, the text cursor moves to indicate the current position of the typing in the active window. As the user continues typing, the text cursor moves closer to the mouse cursor until the mouse cursor obstructs the text cursor. Once the text cursor becomes obstructed by the mouse cursor, the user will become inconvenienced or disrupted from typing in the active window.
Therefore, a need exists for a method, and apparatus for processing two screen pointers, e.g., a text cursor and a mouse cursor, in the viewable screen area such that the one screen pointer does not obstruct the other screen pointer.
The invention provides a method, article of manufacture and apparatus for processing a first screen pointer and a second screen pointer in a viewable screen area, where the first screen pointer moves in response to user activity. Specifically, the method determines whether the first screen pointer moves within a predetermined distance of the second screen pointer. If first screen pointer moves within the predetermined distance of the second screen pointer, the method alters at least one of the first screen pointer and the second screen pointer to prevent the second screen pointer from obstructing the first screen pointer.
In another embodiment of the invention, an apparatus comprising a memory, a display device and a. processor is provided. The memory stores a window display program. The display device displays a viewable screen area containing a first screen pointer and a second screen pointer, where the first screen pointer moves in the viewable screen area in response to user activity. The processor performs a method upon executing the window display program retrieved from the memory. The method performed determines whether the first screen pointer moves within a predetermined distance of the second screen pointer. If first screen pointer moves within the predetermined distance of the second screen pointer, the method alters at least one of the first screen pointer and the second screen pointer to prevent the second screen pointer from obstruction the first screen pointer.
Additionally, a computer readable medium storing a software program is provided, where the software program, when executed by a computer, causes the computer to perform a method. In one embodiment of the computer readable medium, the method determines whether the first screen pointer moves within a predetermined distance of the second screen pointer. If first screen pointer moves within the predetermined distance of the second screen pointer, the method alters at least one of the first screen pointer and the second screen pointer to prevent the second screen pointer from obstructing the first screen pointer.

Method, article of manufacture and apparatus for processing screen pointers in a display

International Business Machines Corporation


A front-end module (FEM) having in-vehicle parts incorporated in a vehicle front section are aggregated and assembled to a heat exchanger support frame, the plurality of in-vehicle parts are classified into first in-vehicle parts, which vibrate at frequencies in a first frequency band, and a second in-vehicle part, which vibrates at a frequency in a second frequency band having a frequency range higher than the frequency range in the first frequency band. The first in-vehicle parts are elastically supported by the heat exchanger support frame via first mount members. The second in-vehicle part is rigidly fixed to the heat exchanger support frame. The heat exchanger support frame is elastically supported by a vehicle body via second mount members.

1. Field of the Invention
The present invention relates to a vibration suppression structure for a front-end module in which a plurality of in-vehicle parts incorporated in a vehicle front section are aggregated and assembled to a heat exchanger support frame.
2. Background Information
There is a known cooling part support apparatus for a vehicle of related art in which a radiator core support that is a substantially rectangular frame member is disposed in a front section of a vehicle body and a radiator is supported in a space surrounded by the radiator core support (see Japanese Laid-Open Patent Application No. 2009-262876, for example).

Vibration suppression structure for front-end module


A semiconductor device includes a semiconductor substrate having a cell region and a peripheral region. A cell array is defined within the cell region, the cell array having first, second, third, and fourth sides. A first decoder is defined within the peripheral region and provided adjacent to the first side of the cell array. A first isolation structure is formed at a first boundary region provided between the first side of the cell array and the peripheral region. A first dummy active region is formed at a second boundary region that is provided between the second side of the cell array and the peripheral region. The first isolation structure has a first portion that has a first depth and a second portion that has a second depth.

The present invention relates to a memory device and method of fabricating the same, and more particularly, to forming a boundary region between cell and peripheral regions in the memory device.
In the memory device, e.g., the NAND flash, the pitch of the isolation trench is becoming smaller and smaller as the technology advances. The isolation trench is gap-filled with an oxide film to form field oxide structure (FOX) or isolation structure. Such an oxide film is typically formed using High Density Plasma (HDP) method. The step-coverage failure of the isolation structure is more likely to occur as the isolation trench is provided with a smaller pitch.
The step-coverage failure in the memory cell region can be quite serious. The step-coverage failure may generate a void in the isolation structure of the memory cell that can affect the reliability of the memory cell. To address this concern, the depth of an isolation trench of the memory cell region is set to 2000 Å or less in order to improve the step coverage.
However, the depth of the isolation trench at the peripheral region tends to be substantially deeper. That is, the voltage applied to the peripheral components of the device generally has not changed even as the technological advance has greatly reduced the size of the device. Accordingly, a transistor formed in the peripheral region continues to be provided with a deep isolation trench to withstand a high voltage of 20V or more.
Currently a boundary region between the cell region and the peripheral region is defined by forming an active region or forming an isolation layer. If the active region is formed, a gate oxide layer thinning phenomenon may occur at an edge of the active region. If a high voltage of about 20V is applied to the gate line during a NAND flash memory device operation, the gate oxide breakdown could occur at the thinned-out portion of the gate oxide layer. This would result in device failure.

Flash memory device and method of fabricating the same