An improved process for the manufacture of maleic anhydride by catalytic oxidation of a nonaromatic hydrocarbon having at least four carbon atoms in a straight chain, in which a gas containing oxygen and hydrocarbon is passed through a fixed catalyst bed in a tubular reactor. The activity of the catalyst bed is graded in such manner that the reactor can be operated at an initial (feed gas) hydrocarbon concentration of over 1.5% by volume, an integrated average temperature difference between gas and cooling fluid of at least about 15.degree. C. over that portion of the bed in which the gas temperature exceeds the cooling fluid temperature, and a productivity of at least about 5.0 lbs. maleic anhydride per hour, without the temperature difference between the gas and the cooling fluid exceeding 80.degree. C. at any point in the catalyst bed during the course of the reaction. Preferably, the catalyst activity and the gas permeability of the bed vary in the direction of gas flow so that both the catalyst activity and the pressure drop per unit distance are lower in a critical region, where the combination of temperature and hydrocarbon concentration could otherwise cause the reaction to proceed at an excessive rate, than they are in a region of low temperature and low hydrocarbon concentration. Significant and unexpected improvement in reactor performance is achieved by the combination of a graded catalyst charge and incorporation of a catalyst modifying organophosphorus compound in the hydrocarbon feed.

This invention relates to the field of catalytic oxidation of hydrocarbons to produce oxygenated hydrocarbons, and more particularly to an improved process for the preparation of maleic anhydride and other oxygenated hydrocarbons at enhanced productivity.
Conventionally, maleic anhydride is manufactured by passing a gas comprising n-butane and oxygen through a fixed catalyst bed tubular plug flow reactor containing a catalyst that consists of mixed oxides of vanadium and phosphorus. The catalyst may contain minor amounts of promoters or activators such as iron, lithium, zinc, chromium, uranium, tungsten, various other metals, boron and/or silicon. Other nonaromatic hydrocarbon starting materials which contain at least four carbon atoms in a straight chain, for example, 1-butene, 2-butene, 1,3-butadiene and mixtures thereof, can also be used in the process. The hydrocarbon starting material reacts with the oxygen to produce maleic anhydride and various by-products, including carbon monoxide and carbon dioxide.
The oxidation of n-butane or other of the above-mentioned starting materials is highly exothermic. Conversion of n-butane to maleic anhydride releases about 350 kCal/mole. Conversion to carbon dioxide, which is equivalent to combustion of the n-butane, releases about 650 kCal/mole. Thus, a substantial amount of heat must be removed in the course of the reaction. Conventionally, a shell and tube heat exchanger is used as a reactor, with the catalyst packed in the tubes, through which the reactant gases are passed. A cooling fluid, typically molten salt, flows over the outsides of tubes. Because the length to diameter ratio of the tubes is high, the reaction system approaches plug flow. The cooling capacity is substantially uniform throughout the reactor, but the rate of reaction varies widely with the concentration of hydrocarbon reactant and temperature. Because the reactant gases are normally introduced into the catalyst bed at a relatively low temperature, the reaction rate is low in the region near the inlet, despite the fact that hydrocarbon concentration is at its maximum at this point. As the gas temperature increases due to initial reaction, heat is generated at a rate that increases as a function of distance in the direction of gas flow, requiring the gas temperature to rise as a function of distance in order that the cooling rate per unit of tube length balances the rate of heat generation per unit of tube length. The temperature continues to increase with distance along the length of the reactor tube until a point is reached at which depletion of the hydrocarbon causes the rate of heat generation to slow, allowing the remainder of the reactor to operate at a lower temperature differential. Thus a point of maximum temperature is reached, which is generally referred to as the "hot spot" of the reactor. When the reactor is under proper control, the hot spot occurs in an intermediate region of the catalyst bed, and from this point downstream to the gas exit, the temperature typically declines.
Problems occur in operation of the reactor if the hot spot temperature becomes too high; and especially serious problems can arise if it propagates or migrates to the exit of the reaction zone. Typically, the salt bath cooling fluid is maintained at a temperature of about 380.degree. to about 460.degree. C. If the gas temperature exceeds about 500.degree. C., or the difference between the gas temperature and the salt bath temperature is greater than about 80.degree. C., the catalyst degrades at an accelerated rate due to sintering or other effects, resulting in a progressive decline in the productivity of the plant and, in some instances, the selectivity of the catalyst. Moreover, because the reaction rate constant increases exponentially with temperature, the reaction can run away if the gas temperature substantially exceeds a temperature 80.degree. C. higher than the cooling fluid. Additionally, higher temperatures tend to favor the complete oxidation of the hydrocarbon to CO.sub.2 and water. This not only reduces the yield and productivity of desired product, but the higher heat of reaction released in conversion to CO.sub.2 compounds the problem by further increasing the temperature.
Excessive deactivation of catalyst due to thermal degradation can cause the hot spot to migrate to the exit end of the catalyst bed. In this case, it becomes necessary to lower the hydrocarbon concentration or space velocity. Otherwise, the exit gas may contain sufficient unreacted hydrocarbon to create risk of an uncontrolled reaction in downstream equipment. Reducing the hydrocarbon or space velocity results directly in a loss of productivity.
Accordingly, it has been a high priority in the art to design and operate maleic anhydride and other catalytic oxidation reactor systems to control both the magnitude and location of the temperature peak, the so-called hot spot of the reaction. Efforts have also been directed to developing systems in which the reactor temperature profile is as even as possible, thereby allowing operation at higher average temperature for higher productivity.
Catalyst packs having graded activity in the direction of gas flow have been proposed to meet various objectives. Such catalyst systems generally include a region of relatively low activity where the so-called hot spot of the reactor occurs in order to minimize the temperature peak at that hot spot. This stratagem serves several purposes. First, it helps to protect the system against the runaway reactions that can occur if the hot spot temperature peaks too high. If the catalyst activity is relatively low in such region, the resultant reaction rate moderation prevents the temperature from rising as high as it otherwise generally would. Moreover, at a given temperature, the reaction rate is relatively low, so that self-acceleration into dangerous conditions is inhibited. Controlling the temperature peak favors the preferred reactions in competition with the high activation energy side reactions that produce CO and CO.sub.2. It also minimizes the rate of degradation of the catalyst, which increases with temperature. Additionally, it allows operation at higher than conventional temperatures upstream and especially downstream of the hot spot, without risking runaway reaction, thereby providing a higher overall rate of heat dissipation, equating to a higher rate of production.
Palmer et al. U.S. Pat. No. 4,342,699 describes a process for the manufacture of maleic anhydride using a fixed catalyst bed that is graded so that reactivity increases over a least a portion of the effective reaction zone length from minimum activity nearest the feed end of the reaction zone to maximum activity nearest the exit end. Maleic anhydride is removed from the reactor effluent and unreacted n-butane is recycled to the feed end after a purge for removal of inerts. The composition of the feed gas is on the hydrocarbon rich side of the flammability envelope. The combination of n-butane rich feed and graded catalyst is said to result in improved productivity of maleic anhydride as compared to processes that do not use this combination of features. Palmer et al. prefer that the entire effective length of the reaction zone is graded from minimum activity at the feed end to maximum activity nearest the exit end, but also contemplate grading only a portion of the effective length in such manner, providing a zone of high or intermediate activity at the inlet end to provide a preheating zone. Palmer et al. describe grading of catalyst activity by dilution with inert particles having a size and shape at least roughly similar to the catalyst pellets. Several other methods for achieving the desired activity gradient are mentioned. One is to employ a supported catalyst in which the proportion of support decreases, and correspondingly the proportion of active catalyst increases, from the minimum to the maximum reactivity zones. Another is to partially impregnate a support with catalyst. A third is to use different catalysts, or varying blends of different catalysts, in the individual reactivity zones.
Mummey U.S. Pat. No. 4,855,459 describes an improved process for the catalytic oxidation of various C.sub.4 hydrocarbons to maleic anhydride under conditions sufficient to provide a single pass conversion of at least 70% of the hydrocarbon fed. The catalyst is diluted with inert solid material effective to stabilize the maleic anhydride yield such that the average yield decay is less than 0.30% of the established maleic anhydride yield per month over an extended period of sustained operations. Alternatively, a supported catalyst is used and the proportion of active catalyst on the support increases from the maximum to the minimum dilution stage. In the process of the '459 patent, suitable configurations for the diluted catalyst pack are not narrowly critical and vary depending upon overall catalyst pack length, production rate, composition of the active catalyst, reaction conditions and the like. Nonlimiting examples include (a) a configuration in which the diluted catalyst pack is graded in dilution such that dilution decreases over at least a portion of the catalyst pack length from maximum dilution nearest the feed inlet end to minimum dilution nearest the exit end and (b) a configuration in which a first portion of the catalyst pack, proceeding from the feed inlet end to the exit end, has minimum dilution and the remainder of the catalyst pack is graded from maximum dilution nearest the feed inlet end to minimum dilution nearest the exit end. In the latter case the initial minimum dilution zone is relatively short and can serve as a preheating zone for the gas feed stream. The catalyst pack is graded in dilution such that the minimum dilution occurs within that region of the reaction zone which extends over the initial 50% of the length of the catalyst pack in which the hottest point of the reaction zone is located.
Smith and Carberry, "On the Use of Partially Impregnated Catalysts for Yield Enhancement in Non-Isothermal Non-Adiabatic Fixed Bed Reactors," The Canadian Journal of Chemical Engineering, 53, pp. 347-349 (1975) discloses the use of catalyst pellets that are partially impregnated with active catalyst in the oxidation of naphthalene to phthalic anhydride. The paper reports the results of varying both the fraction of pellet radius occupied by deposited catalyst and the total amount of catalyst deposited. Partial impregnation was found to improve yields. By comparison with partially impregnated catalyst, tests with fully impregnated catalyst required relatively small catalyst particles, higher pressure drop and consequently higher inlet gas pressure. This reference mentions the use of different catalyst in zones of the bed in which different steps of a multi-step reaction predominantly occur, but does not disclose the grading of catalyst impregnation or pellet size along the length of the reactor.
Buchanan and Sundaresan, "Optimal Catalyst Distribution and Dilution in Nonisothermal Packed Bed Reactors," Chem. Eng. Comm., 1987, Vo. 52, pp. 33-51 presents conditions for optimal loading with a two-dimensional reactor model and applies them to catalyst dilution in a butane oxidation reactor. The reference refers to catalyst dilution with inerts as an important special case of non-uniform catalyst loading, and notes that under some circumstances a chemically non-uniform catalyst loading may be preferable to simple physical dilution with inerts. In discussing certain other references that describe chemically non-uniform catalyst, Buchanan et al. speculate that the motivation to use them may depend partly on the convenience of the various catalyst preparation procedures or on considerations of catalyst longevity. They note that, for the vanadium catalyst used for C.sub.4 oxidation, higher phosphorus content in the vicinity of the hot spot may help stabilize the catalyst against deactivation. They further observe that one opportunity for chemical variation arises when there is an inverse relationship between activity and selectivity. In oxidation of both butane and butene, as the phosphorus content of the catalyst increases, overall activity declines but selectivity to maleic anhydride increases. Buchanan et al. present data showing the effect of various catalyst dilution schemes on yield of desired product.
Kerr U.S. Pat. No. 3,474,041 describes the addition of an organophosphorus compound for reactivation of mixed vanadium and phosphorus oxide catalyst for the oxidation of butane to maleic anhydride. Various means for introducing the organophosphorus compound into the catalyst bed are described including introduction of the phosphorus compound into the butane and oxygen containing feed gas to the reactor. Best results are said to be obtained by adding the organophosphorus compound after discontinuing hydrocarbon flow and blowing the reactivated catalyst with air prior to the re-introduction of hydrocarbon. The reference notes that the phosphorus compound can serve as a stabilizer as well as a reactivator for the catalyst.
Click, et al., U.S. Pat. No. 4,515,899 describes steam regeneration of phosphorus treated vanadium/phosphorus/oxygen catalyst for maleic anhydride. The reference notes that treatment of the catalyst with phosphorus compound reduces activity but increases selectivity, the loss of activity being compensated for by an increase in temperature of the reaction. The reference reports that, in practice, it is found that phosphorus compounds concentrate near the feed end of the reactor, thus requiring that the amount of phosphorus addition be limited. Addition of steam after treatment with phosphorus compound re-distributes the phosphorus compound more evenly through the reaction zone.
Edwards U.S. Pat. No. 4,701,433 applies both water and a phosphorus compound in situ in amounts sufficient to partially deactivate a portion of the catalyst. Edwards teaches that the addition of the combination of phosphorus compound and water serves to deactivate the region in which the hot spot of the reaction occurs, thereby moving the hot spot downstream and apparently allowing for reactivation of the region in which the hot spot previously occurred. A similar disclosure is contained in Edwards U.S. Pat. No. 4,810,803. Both references disclose the use of alkyl phosphates and alkyl phosphites for such purpose.
Edwards U.S. Pat. No. 4,780,548 also describes a process for reactivation of a phosphorus/vanadium/oxide catalyst for the oxidation of n-butane to maleic anhydride.
Although the literature is replete with publications which discuss various aspects and purposes of catalyst activity modification in the fixed bed catalytic oxidation of hydrocarbons, a need has remained for catalyst systems which provide for the manufacture of maleic anhydride with maximum productivity.
Productivity of a catalytic oxidation system for the manufacture of maleic anhydride can be defined by the equation: ##EQU1## where GHSV is the gas hourly space velocity (hr.sup.-1). Computations indicate that the productivity can be converted to metric units by applying the factor 16.0, leading to the relationship: ##EQU2## Molar yield in turn is the product of conversion and selectivity. Conversion is a function of a number of operating variables including, but not limited to, temperature, space velocity and active catalyst density in the reactor tube. Because the reaction rate constant is highly temperature dependent, molar yield and productivity necessarily depend on the ability to operate the reactor at a relatively high average temperature without suffering runaway reaction, excess CO.sub.2 formation or catalyst degradation due to excess hot spot temperature.
Pressure drop through the reactor system is another variable which materially affects the productivity and performance of the reaction system. To achieve the same space velocity at high pressure drop not only consumes mechanical energy, but requires a higher hydrocarbon partial pressure at the reactor inlet. Because the hot spot temperature and tendency to runaway may be highly sensitive to the partial pressure of the hydrocarbon reactant, high pressure drop may require the initial hydrocarbon content of the gas to be curtailed to reduce the parametric sensitivity of the system, thus adversely affecting the productivity.

High productivity process for the production of maleic anhydride


According to one embodiment, an actinic-ray- or radiation-sensitive resin composition includes (A) a resin that when acted on by an acid, increases its solubility in an alkali developer, (B) a compound that when exposed to actinic rays or radiation, generates an acid, and (C) a resin containing at least one group selected from among the following groups (x) to (z) and further containing at least either a fluorine atom or a silicon atom, in which three or more polymer chains are contained through at least one branch point, (x) an alkali-soluble group, (y) a group that when acted on by an alkali developer, is decomposed to thereby increase its solubility in the alkali developer, and (z) a group that when acted on by an acid, is decomposed to thereby increase its solubility in an alkali developer.

1. Field of the Invention
The present invention relates to an actinic-ray- or radiation-sensitive resin composition for use in a lithography operation employed in a semiconductor production process for an IC or the like, production of a circuit board for a liquid crystal, a thermal head or the like and other photofabrication, and relates to a method of forming a pattern using the composition. More particularly, the present invention is concerned with an actinic-ray- or radiation-sensitive resin composition that is suitable for exposure using a liquid-immersion projection exposure apparatus in which a far ultraviolet light of wavelength 300 nm or shorter is employed as a light source and with a method of forming a pattern using the composition.
2. Description of the Related Art
In accordance with the miniaturization of semiconductor elements, the wavelength shortening of the exposure light source and the realization of high numerical apertures (high NA) for projector lenses have been advanced. For achieving the enhancement of resolving power by further wavelength shortening, it is heretofore known to employ a method in which the space between a projector lens and a sample is filled with a liquid of high refractive index (hereinafter also referred to as an "immersion liquid"), generally called a liquid-immersion method. The liquid-immersion method is effective in all pattern configurations. Further, this can be combined with a super-resolution technology, such as a phase shift method or a modified illumination method, now under study.
Since the emergence of the resist for a KrF excimer laser (248 nm), it has been of common practice to, in order to compensate for any sensitivity deterioration caused by light absorption, employ an image forming method through chemical amplification as a resist image forming method. Brief description of a positive image forming method through chemical amplification is given below by way of example. Upon exposure, an acid generator is decomposed in exposed areas to thereby generate an acid. At the bake after the exposure (Post-Exposure Bake: PEB), the generated acid is used as a reaction catalyst so that an alkali-insoluble group is converted to an alkali-soluble group. Thereafter, alkali development is carried out to thereby remove the exposed areas. Thus, the relevant image forming method is provided.
The resist for an ArF excimer laser (193 nm) utilizing this chemical amplification mechanism is now becoming mainstream. However, in the liquid-immersion exposure, the resist has posed not only the problem of pattern collapse such that a formed line pattern collapses to thereby cause a defect in device production but also the problem of line edge roughness involving roughening of pattern side walls.
Moreover, it is pointed out that when such a chemical amplification resist is applied to liquid-immersion exposure, as the resist layer is brought into contact with the immersion liquid during the exposure, not only would the resist layer suffer a property alteration but also components having an unfavorable influence on the immersion liquid would leach from the resist layer. In this connection, patent references 1 to 4 describe examples of inhibiting the leaching by the addition of a resin containing a silicon atom or a fluorine atom.
Further in the liquid-immersion exposure process, in the event of exposure using a scan type liquid-immersion exposure machine, the exposure speed is decreased when the immersion liquid fails to move while tracking a moving lens. This would negatively affect productivity. When the immersion liquid is water, it is preferred for the resist film to be hydrophobic from the viewpoint of superiority in water tracking properties.
However, even when the liquid-immersion exposure is carried out using the above-mentioned technology, it is likely to encounter development defects, known as blob defects, and scumming. Thus, overcoming these problems is demanded.
[Patent reference 1] Jpn. Pat. Appln. KOKAI Publication No. (hereinafter referred to as JP-A-2006-309245),
[Patent reference 2] JP-A-2007-304537,
[Patent reference 3] JP-A-2007-182488, and
[Patent reference 4] JP-A-2007-153982.

Actinic-ray- or radiation-sensitive resin composition and method of forming pattern using the composition


A high strength surgical suture formed of ultrahigh molecular weight polyethylene (UHMWPE) yarns, the suture being coated with native or denatured collagen. The braided jacket surrounds a core formed of twisted yarns of ultrahigh molecular weight polyethylene. The suture has exceptional strength, is ideally suited for most orthopedic procedures, and can be attached to a suture anchor or a curved needle.

1. Field of the Invention
The present invention relates to high strength surgical suture materials, and more particularly to braided suture blends of ultrahigh molecular weight polyethylene having bioabsorbable coatings.
2. Description of the Related Art
Suture strength is an important consideration in any surgical suture material. One of the strongest materials currently formed into elongated strands is an ultrahigh molecular weight long chain polyethylene, typically used for fishing line and the like, which is sold under the trade names Dyneema or Spectra. This material is much stronger than ordinary surgical suture, however, it does not have acceptable knot tie down characteristics for use in surgical applications.

High strength suture coated with collagen


A system and method providing an optimal way to create, manage and use resource data is provided. In an exemplary embodiment, the system and method provide the ability to store resource data in a library, namely a resource library. A resource library includes resource files that can be attached to a regular data file either automatically, for example, by setting an environment variable, or manually. More than one resource library or resource file may be created and simultaneously attached to a data file. The resource file defines attributes of elements that may be used in creating the CAD model. Typically, the resource library includes attributes that are to be standardized across a project, file, or model.

Computer-aided design (CAD) drawings prepared by architects, engineers, designers, planners, and the like require large amounts of data to be stored in files. CAD software includes an API to access the large quantities of data. Applications such as, e.g., MicroStation® products, which are developed by Bentley Systems, Inc., Exton, Pa. U.S.A., and AutoCAD® products, which are developed by Autodesk, Inc., San Rafael, Calif., U.S.A. are typical of such CAD software, which may be used in the Engineering, Construction, and Operations (ECO) marketplace.
A typical CAD project employed in the engineering context is stored in numerous files. Each file typically contains one or more engineering models, each of which represents an engineering domain (e.g., structural, electrical, mechanical, plumbing). Moreover, each engineering model requires numerous items represented by a series of elements to support the complex and precise nature of each design. In this context, the term "element" is used to mean a record containing a variable number of bytes of data arranged in a format that can be interpreted by a program. The term "element" differs from the common notion of an "object" in that each element can have a variable number of bytes, whereas the size of an object is typically defined by its class. It is the variable-sized nature of elements that causes their persistent storage to be complicated, because they cannot be written in fixed sized records and arranged in tables, as is typically done in relational databases, for example.
Each item in a model is represented by at least one element or an aggregation of elements. For example, a structural drawing can hold the column and beam layout for a floor plan, which are internally represented by lines, squares and rectangles and additional properties. In this example, an individual beam may be a collection of lines, squares and rectangle elements. The structure of the floor plan may be more complex and require many nested levels of elements to accurately provide a structural representation.
Attributes define the characteristics of an element, for example, its color or line width, and how the element is displayed to a user. It is common practice for attributes of elements stored in a CAD data file to be controlled by a named style. A style itself is a non-graphical entity which records a particular set of values for the attributes needed to construct the element. Similarly, a level (also known as layer) may also control the attributes of elements. A level is also a non-graphical entity. Every element is typically associated with one or more levels. A style is applied to specific types of elements, such as text and dimension elements.
Every level and style has a unique name that identifies its data. Such data can be generalized by calling it "resource data". There can be other forms of resource data such as "Named Views" or "Named Viewgroups." A common feature of such resource data is that it provides a way to reuse information that is used repeatedly or that must be controlled in a centralized fashion.
Every CAD data file can have its own set of resource data. Typically, a group of users work on a set of files during the design and construction process, which set of files in many instances may run into hundreds of files. Files may reference each other. The sum of all files and their implied relationships define a project. Each file consists of a sub-set of all the data in a project.
Typically, multiple CAD data files of a project need a common sub-set of resource data. As the project progresses, this data tends to change and grow. Any data stored in a particular design slowly becomes out of date from the master list. Users need a simple method to update individual files to match the resource data.
Moreover, over time many projects are created. Different projects need different sets of resource data. Projects span disciplines and departments. Different disciplines and departments need their own sets of resource data. Combining the resource data required by different projects, disciplines and departments creates the need for a large number of individual resource data entities and consequently a need to standardize the resource data.
Previous methods for creating standardized resource data and for updating individual design files to match the resource data have not addressed all user needs. For example, MicroStation v.7 Settings Manager is a system that provides users with access to settings and styles. The system is centralized in that all users can access the resource data from one library file. However, the library file is in a specialized format. A special tool must be used to create and maintain data in the library file. Also, the library file must be accessed using a different special tool in order to load the data before starting the tool that utilizes this data. Furthermore, this system only allows the attachment of a single data library to a design file.
The MicroStation v.7 Cell Library System allows the user to acquire graphic data from a collection of library files. The graphic data is also in a specialized format and requires a special tool to export the data to the library. Furthermore, this system does not store most of the non-graphic data due to the specialized file format.
AutoCAD Design Center is a tool used to import cells and styles from other files. Although the files are of the same format as the working file, the data is only available through a specialized tool. The data must be imported into the current file before it can be used as part of the drawing. Also, there is no synchronization from the library data to the current data. Furthermore, each file from which data is imported must be selected individually rather than having a list of all available resource data.
Thus, there is a need for a system and method to centralize, control and distribute predefined information used for creating CAD files and models. The system and method should allow for central control of the information to limit changes, but allow the information to be instantly accessible to users at the point at which the information is to be applied.

System, method and computer program product for managing CAD data


An apparatus and a method for sorting workpieces (204) includes multiple conveyors (201, 202), a scanner (208), an offloading device (216), a workpiece processor (218), and a computer (210). The computer has instructions for carrying out a method for sorting that includes obtaining the physical parameters of the workpiece by scanning the workpiece, obtaining an updated distribution of a physical parameter of a population of workpieces, obtaining an updated loading on each conveyor, obtaining the workpiece processor's capacity, obtaining a processing parameter indicating the required amount of workpiece processing to be performed, and obtaining each conveyor's speed. This information is used to place the workpiece on a conveyor in a manner that is calculated to utilize the optimum amount of workpiece processor capacity, while at the same time maintaining an even belt loading. The computer is in communication with conveyor speed drivers (250, 252) and the offloader to adjust retention time and/or conveyor loading.

Many freezing and cooking operations utilize conveyor belts that carry workpieces through a processing section of a freezer or an oven or even a series of freezers or ovens. In order to achieve the desired amount of freezing or cooking, the conveyor belt speed is set to a speed that will fully freeze or cook the largest of the workpieces. This is to ensure that all pieces meet the necessary minimum requirements, many times mandated by regulations. While this accomplishes the desired goal of not allowing workpieces to pass unprocessed or under pressure through the freezer or oven, the operation may be inefficient, since many of the workpieces will be unnecessarily overprocessed. Ideally, each workpiece would spend only the amount of time in the freezer or oven that is required to fully freeze or cook it to the required specifications, without significant loss of freezer or oven capacity.
One approach to this problem has been to "piece sort," meaning employing multiple conveyor belts within a single oven or freezer with each belt running at a different speed. This arrangement allows the workpieces to be sorted by size ahead of the processing operation. In a three-conveyor system, for example, the smallest pieces are placed on the fastest moving belt, the medium-sized pieces are placed on the next slowest belt, and the largest pieces are placed on the slowest belt. The size range for each conveyor may be determined from a manual sampling of workpiece sizes. By knowing the performance characteristics of the processing operation for the particular workpiece, each belt speed can be adjusted for a population of workpieces that fall within a certain size range. Utilizing multiple conveyor belts, and sorting ahead of the processing operation, may provide a temporary solution, but this situation may be short-lived. Due to the ever-changing variation in the sizes of workpieces, the initial sorting criteria may not be representative as time progresses. The inevitable result is a shift of product from the fastest belt to the slower belts if the average size of the workpieces was to increase. Conversely, if the average size was to decrease, the products would start to accumulate on the fastest moving belt. Too much product on one belt when the other belts are not at full capacity is also not utilizing resources to their fullest capability.
Another method of sorting is called "even flow," meaning the lines are kept as full as possible regardless of the workpiece weight or size. This practice leads to the possibility that workpieces will be over- or underprocessed.
An "even flow" sort alone may require overcooking or overfreezing product as the size distribution changes, without a change in retention time/conveyor speed. "Piece sorting" alone can move all product to a single retention time, making a single retention time a bottleneck, while other retention time line or belts are underutilized. Thus, the conventional ways of sorting can eventually lead to gross inefficiencies.
What is lacking in the art is a method of sorting by size combined with the ability to provide even product flow to maintain the belt's loading at its optimum. The present invention addresses this need and seeks to provide further related advantages.

Sorting system for multiple conveyor belts


A method for monitoring and controlling IGBT temperature in a power converter of an electrical power system includes generating a plurality of temperature signals from a plurality of switching devices via a plurality of temperature sensors. The method also includes selecting a primary switching device from the plurality of switching devices to estimate a primary temperature thereof. Further, the method includes determining the primary temperature of the primary switching device via a temperature measurement circuit communicatively coupled to the primary switching device. Moreover, the method includes comparing remaining temperature signals (or a function thereof) to the primary temperature via at least one comparator circuit. If one of the remaining temperature signals (or the function thereof) exceeds the primary temperature, the method also includes implementing a control action to address the increased temperature.

Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. For example, rotor blades typically have the cross-sectional profile of an airfoil such that, during operation, air flows over the blade producing a pressure difference between the sides. Consequently, a lift force, which is directed from a pressure side towards a suction side, acts on the blade. The lift force generates torque on the main rotor shaft, which is geared to a generator for producing electricity.
During operation, wind impacts the rotor blades and the blades transform wind energy into a mechanical rotational torque that drives a low-speed shaft. The low-speed shaft is configured to drive the gearbox that subsequently steps up the low rotational speed of the low-speed shaft to drive a high-speed shaft at an increased rotational speed. The high-speed shaft is generally coupled to the generator so as to rotatably drive a generator rotor. In many wind turbines, the generator may be electrically coupled to a bi-directional power converter that includes a rotor-side converter joined to a line-side converter via a regulated DC link. The line side converter converts the DC power on the DC link into AC output power suitable for the electrical grid bus. In particular, switching devices (e.g. IGBTs) used in bridge circuits of the line side power converter can be modulated to convert the DC power on the DC link into AC power on the line side bus. The AC power from the power converter can be combined with the power from the generator stator to provide multi-phase power (e.g. three-phase power) having a frequency maintained substantially at the frequency of the electrical grid bus.
Such wind turbine power systems are generally referred to as a doubly-fed induction generator (DFIG). DFIG operation is typically characterized in that the rotor circuit is supplied with current from a current-regulated power converter. As such, the wind turbine produces variable mechanical torque due to variable wind speeds and the power converter ensures this torque is converted into an electrical output at the same frequency of the grid.
The IGBT(s) of the power converter are responsible for creating important waveforms in the power converter by their switching action. Such switching action can generate excessive heat, thereby increasing the temperature of the IGBTs. As such, it is important to monitor the temperature of the IGBTs to avoid the risk of failure. In conventional power converters, there are generally two sets of IGBTs on a phase module, with each IGBT set typically sitting adjacent to the heatsink in the phase module. In such systems, only one temperature is read per IGBT set.
As future power systems continue to include more IGBTs per set, it becomes increasingly important to measure each IGBT temperature. Thus, the present disclosure is directed to a system and method for measuring and controlling IGBT temperature in a power converter of an electrical power system that addresses the aforementioned issues.

System and method for controlling multiple IGBT temperatures in a power converter of an electrical power system


A metered induction two cycle engine is presented. In accordance with the metered induction two cycle engine, an aspirating cylinder (or pulsing air-charger) is connected to a combustion cylinder by a voluminous transport duct having a valve disposed therein. The valve permits flow from the aspirating cylinder and duct to the combustion cylinder and prohibits flow in the opposite direction. The duct acts as an extension of the clearance volume of the aspirating cylinder. The valve is actuated when the pressure in the duct exceeds the pressure in the combustion cylinder. Further, the aspirating cylinder leads the combustion cylinder by a fixed amount to provide a disciplined flow of mixture (i.e., air and fuel) into the combustion cylinder.

This invention relates to internal combustion two cycle engines. More particularly, this invention relates to a metered induction two cycle engine.
Internal combustion two cycle engines generally comprise a compression chamber in which a fuel/air mixture (generally a fuel/oil/air mixture) is partly compressed and transferred into a combustion chamber for further compression and ignition. The two cycle engines have been configured in a variety of ways, in attempts to improve efficiency, power and other features. Examples of these attempts are represented by U.S. Pat. Nos. 2,136,293; 2,522,649; 3,543,735; 3,880,126 and 3,774,581.
A two cycle engine which does not require the mixing of fuel and oil is presented in U.S. Pat. No. 2,136,293 to Gentry. The engine of the '293 patent inducts air for combustion via a piston device and provides a passage for air to the combustion chamber. The induction of air or mixture (i.e., fuel/air) into the passage results in a full downward (i.e., induction) stroke of the piston against full manifold vacuum. The injector piston includes piston porting that requires the whole induction stroke of the piston be made against high vacuum on the piston head followed by a rush of inducted material, thus increasing the pumping losses.
An increased power two cycle engine is presented in U.S. Pat. No. 2,522,649 to Tenney, wherein porting of two pistons (and their relative size) is arranged to provide supercharging of combustion cylinder for high max output. A lack of significant clearance volume above the pumping piston to be re-expanded before drawing new charge through results in high negative pumping work during light load operation. FIG. 11 of U.S. Pat. No. 2,522,649 shows an alternate single-crank-throw variant of the basic disclosure which, coincidentally provides some re-expansion volume to the transport duct except during those portions of the induction stroke when the port is covered by the piston extension. Energy is lost in the power stroke of the combustion piston due to early release of pressure during the cycle. Further, the impingement of hot combustion gases under pressure against the pumping piston as it closes off the transfer duct is expected to result in pumping piston galling and seizure.
A two cycle diesel engine is presented in U.S. Pat. No. 3,543,735 to Kruckenberg et al. The engine includes a pumping cylinder in communication with a power cylinder via a conduit having a significant volume. The pistons are at a 90.degree. relationship with each other. This engine is limited to diesel operation since any attempt to operate it with a throttled inlet would result in gross back-flow all the way from the exhaust manifold back through the combustion cylinder, the conduit and into the pumping cylinder area. This is caused by the air inlet port being uncovered by the piston in the pumping cylinder at about the same time that the inlet ports are covered by the piston in the power cylinder, thus precluding any recompression of the inducted gases before their exposure to exhaust conditions. Furthermore, the use of the pure piston-ported inlets constrains the inlet port opening and closing timing to fixed points in the piston stroke and precludes the use of different quantities of gas induction stroke at various load conditions.
Split cylinder engines are presented in U.S. Pat. No. 3,880,126 to Thurston et al and U.S. Pat. No. 3,774,581 to Lundy, wherein the engine includes an induction cylinder and a power cylinder with a chamber therebetween. A spark plug is disposed in the chamber for ignition of the mixture. Mechanical valves (i.e., poppet valves) are employed to control flow, which will present a severe restriction on engine operation speeds because of the relatively small portion of an engine revolution during which they must be opened and closed for two-cycle operation. No re-expansion volume is provided in open communication with the induction cylinder, which results in the stroke of the piston in the induction cylinder being made entirely against the restraining force of intake manifold vacuum. The transfer vales between the induction and combustion cylinders are subject to combustion temperature and pressure, which will restrict operating speeds, due to the heavy construction required. The engine of U.S. Pat. No. 3,774,581 includes a combination poppet and reed valve at the inlet port of the power cylinder. The reed feature of the valve allows for late opening of the intake valve and prevents development in the induction cylinder of vacuum which is even more impaired than that in the intake manifold.
Generally outboard motors are two cycle engines. These engines generally comprise a piston which moves upward in a cylinder thereby compressing a live charge above the piston prior to its ignition by a spark plug. By this upward piston motion a vacuum is created in a crankcase and a combustible gas flows into this area surrounding the crankshaft and a connecting rod through a reed valve at the crankcase. As the piston descends on its power stroke, the gases in the crankcase are compressed (i.e., the reed valve closes automatically when the crankcase pressure rises above inlet manifold pressure) until such time as the piston uncovers an intake port in the cylinder, thus allowing these compressed gases to rush into a cylinder and expel the burned gases from the last explosion into an exhaust manifold. Oil must be added to the fuel to lubricate the lower portions of the engine, since no reservoir of liquid oil may be maintained in a crankcase that is serving as a transport chamber for induction gases.


The present disclosure provides a resource authorization method for deployment of a VNF, a VNFM, an NFVO, a storage medium and a device. The resource authorization method includes steps of: determining, by the VNFM, whether or not there is a resource request; in the case that there is the resource request, transmitting, by the VNFM, a resource authorization request to the NFVO; receiving, by the VNFM, a resource authorization response from the NFVO, the resource authorization response containing a resource authorization result; and processing, by the VNFM, the resource authorization result.

In conventional NFV architecture stipulated by European Telecommunications Standards Institute (ETSI), Management and Orchestration (MANO) networking mainly includes an NFVO platform, a VNFM and a Virtual Infrastructure Management (VIM). The NFVO platform takes charge of the authorization of global resources as well as the management of a network service life circle. The VNFM takes charge of the management of a life circuit of a VNF. The VIM is configured to provide a virtual resource pool to an upper layer.
There are the following two schemes for extension in the related art. In Scheme 1, in the case that a resource authorization request is initiated by the VNFM to the NFVO, the VNFM may specify a requested resource volume. At this time, the VNFM may request resources simply but does not know the resource distribution in each resource pool, so it is impossible for the VNFM to deploy the resources in a designated resource pool as well as deploy the VNF across multiple resource pools. In Scheme 2, in the case that the resource authorization request is initiated by the VNFM to the NFVO, the VNFM may specify the requested resource volume as well as a resource pool indication parameter. In addition, in the case of performing an operation to extend the VNF, the VNFM may deploy an extended part and an original resource within an identical resource pool.
In the related art, it has been proposed that the VNFM needs to specify the requested resource volume and then initiate the resource authorization request to the NFVO. However, the global resources may probably be distributed within a plurality of resource pools, and the VNFM may not know a resource occupation condition of each resource pool. Hence, there are the following defects. In Scheme 1, in the case of initiating the resource authorization request, the VNFM does not specify the resource pool indication parameter, so the VNFM has no authority to decide the resource pool to which the requested resource belongs. In addition, the VNFM does not know the resource occupation condition of each resource pool, so it is impossible to achieve the deployment of the VNF across the resource pools. In Scheme 2, it is able to ensure the deployment of the extended part and the original VNF within the same resource pool in the case of extending the VNF. However, because the VNFM does not know the global resources within the resource pools, it is impossible to ensure that the resource is requested successfully. In addition, it is also impossible to achieve the deployment of the VNF across the resource pools.

Resource authorization method for deployment of virtual network function, virtual network function manager, and network function virtualization orchestrator

China Mobile Communications Group Co., Ltd.


Embodiments of the invention provide a method for regaining memory consistency after a trap via transactional memory. Transactional memory and a transactional memory log are used to undo changes made to memory from a transaction start point up to the point of a trap event. After the trap event is processed, and the changes are rolled back, the program can resume execution at the beginning of the transaction.

1. Field of the Invention
Embodiments of the present invention generally relate to a method for regaining memory consistency after a trap using transactional memory and a transactional memory log.
2. Description of the Related Art
Concurrent computing generally refers to the simultaneous execution of multiple tasks, usually on a multiprocessor system. These tasks are often implemented by a set of threads (short for "thread of execution") contained by a process (an executing computer program). The threads of a particular process often access the same data structures in memory. Allowing multiple threads to access the same data structures may lead to consistency problems and locking techniques are often used to prevent threads from interfering with each other and corrupting memory. For example, if a first thread is modifying a particular data structure in memory, then the data structure may be "locked" to prevent a second thread from accessing or modifying the data structure until the lock is released. Locking, however, is particularly pessimistic. That is, the data structure remains locked to the second thread regardless of whether concurrent access by both threads would lead to an inconsistency.
Further, a locking mechanism may not prevent certain particular types of consistency errors. For example, consider a thread configured to add an element to a doubly linked list. Typically, such a thread would perform the following steps (set forth in a pseudo code format):
Add_element { newNode->previous = node; newNode->next = node->next; node->next->previous = newNode; node->next = newNode; }The first two lines insert the newNode element following the node element and set pointers for the newNode element to the appropriate previous and subsequent elements in the list. The third and fourth line adjusts pointers in the previous and next elements in the list to point to the newNode element. Because concurrent access to these elements could lead could lead to inconsistent results, a locking mechanism may be used to protect the list while the Add_element routine is performed.
However, if a trap event occurred part way through these steps, a locking mechanism might not prevent the list from being left in an inconsistent state. For example, consider the following sequence of program flow:                1. Lock the doubly linked list.        2. Invoke the Add_element routine to add a new element        3. Part way through the Add_element routine, a trap event occurs causing program control to jump to a known jump point previously set for the trap event.        4. Unlock (not reached).In this example, the thread stack is correct, and further processing could occur. However, this sequence leaves the linked list in an inconsistent state and locked. There is no effective mechanism to unlock the list and undo the partial update to the linked list that occurred prior to the trap event. Thus, in cases such as this, unpredictable results may occur depending on how the doubly linked list is parsed, or the application may simply terminate if an application thread subsequently attempted to dereference an uninitialized node pointer.

Methods, apparatus and articles of manufacture for regaining memory consistency after a trap via transactional memory

International Business Machines Corporation


A flexible heat pad for heat transfer to a person's limb. The pad consists of a fabric (preferably cotton) envelope enclosing a load of cereal grains, preferably oats. Preferably, the water content of the oat is precisely monitored to remain within the 9 to 14% range by weight of the oat total weight. The quantity of oat grains inside the cotton envelope must be such as to provide even oat distribution within the cotton envelope enclosure, after deformation, whereby localized grainless pockets within the pad enclosure are substantially prevented. The pad is pre-heated for about two minutes inside a micro-wave oven, at full power setting, before use. Thermal inertia of the oat thereafter allows continuous heat diffusion to the limb for about half an hour. The pad may alternately be put into the freezer from at least four to six hours, to thereafter diffuse cold to the swollen limb part of a mammal.

Known therapeutic heat transfer devices relieve aches, pains, tensions in mammals (warm-blooded creatures, such as humans), and reduce swelling, among other things; they also have cosmetic use for opening the pores of the skin, as in beauty treatments and dermatological uses. This is achieved by promoting blood circulation through the limbs against which the heat transfer device is applied.
The effects of localized thermal transfer to bodily parts with these known thermal transfer devices is well documented in the art. Such heat transfer devices include:
(a) the simple hot water-filled bag, or conversely, the ice pack filled with water ice; PA1 (b) electric blankets, which include insulated, multi-layered, flexible sheets, and a heat cell embedded within the sheets and generating continuous heat upon plugging the electric wire thereof in an electrical wall plug; PA1 (c) chemical steam packs, which generate heat upon unsealing the pack, thus enabling exothermic oxydation of the air-responsive, reactive chemical agent within the pack, for a period of about half an hour--they are used e.g. by alpine skiers inside their hand gloves; see for example U.S. Pat. No. 3,874,504 to Verakas; PA1 (d) mineral-filled heat pads, with a flexible envelope enclosing granular mineral material (usually sand or vulcanite); the pad is pre-heated in an oven before use, to enable slow diffusion of heat absorbed by the mineral crystals--see for example international patent application No PCT/EP90/00785 published on Nov. 29, 1990 in the name of Herbert Hans WAGNER; PA1 (e) gel-based thermal packs, with an envelope enclosing a gel-state material having a substantial water content associated with a liquid-absorbing core, this core including for example propylene glycol and formaldehyde (to extend the overall thermal range of the gel-state of the material before reaching freezing or boiling state)--see for example U.S. Pat. Nos. 4,488,552 issued Dec. 18, 1984 to Micropak manufacturing, inc., and 4,920,964 issued May 1, 1990 to Jack Frost Laboratories inc.; these thermal packs release stored heat slowly, after being pre-heated for a while in an oven, as with the mineral-filled heat pads, supra.
These prior art heat transfer devices, although effective, have a number of drawbacks. The electric blankets, for one, generate magnetic fields. Currently, there is considerable controversy as to whether or not long exposure of biological tissues to high levels of electromagnetic fields is linked to cancerous cell development. Extensive studies on the interaction of electric fields with living matter have brought concerns to the scientific community as to the health hazards associated with electric blankets. See for example the "CRC Handbook of biological effects of electromagnetic fields", Charles POLK editor, CRC Press, Boca Raton Fla. [1986].
Chemical steam packs are of the disposable type, i.e. they can be used only once. Their cost is accordingly high, relative to reusable heat transfer pads such as the mineral-filled pads and the gel pads. Moreover, the dosage of reactive agent inside the sealed pouch is critical in order not to overheat the pouch--indeed, some cases of bodily injuries have been reported a few years ago in the press, from skin exposure to such chemical steam packs due probably to an improperly measured amount (i.e. an amount greater than required) of reactive chemical agent in the pouch.
Gel type heat pads have a tendency to burst if the preheating period exceeds the recommended time period. The margin for error is very small, as is indeed candidly reported in the specification of the two above-noted gel-type U.S. patents. A burst pad becomes unreusable, and may further constitute a safety hazard. Moreover, gel pads tend to produce a so-called "moist" heat, which may not be desirable for everybody.
Mineral-based heat transfer pads have other drawbacks. Because of the extremely low water content of the granular mineral occur between the mineral granules as the flexible pad is repeatedly bent to fit around the various limb parts. Eventually, these granules accordingly become powdery (i.e., their granulometry progressively decreases), so that they may come to escape from the pad through the porous envelope wall. Moreover, mineral materials such as sand define granules each having relatively sharp external edges; such sharp edges are certainly uncomfortable to the skin as they indirectly come in contact therewith through the pad envelope wall. Also, because the granulometry of sand is quite small, it has been found by the three present joint inventors that the granular material pressure load-induced movement within the pad envelope and consequent distributive flow therein tend to easily generate empty grainless pockets within the pad envelope. In other words, instead of the granular material desirably spreading equally all along the enclosure of the pad envelope, the sand will tend to gather at the two opposite ends of the pad, under gravity-borne forces, while the intermediate section thereof (that is, the main pad section coming in contact with the body part to be soothed) will be substantially free from any heat-releasing core material (the two corresponding sections of the opposite main walls of the envelope will abut flatly against one another), an inefficiency.


A packet contains an array of processing operations that are to be performed by a node. Each node in a data forwarding network performs the processing it has to perform in accordance with the array of the processing operations contained in the packet.

As a technique that allows a program to be run on nodes, such as routers or switches, arranged on a network, there is known an active network (see Non-Patent Document 1). There is disclosed in Patent Document 1 an active network provided with a signaling control unit which, by advance signaling, arrays an active code in a network's node.
In Patent Document 2, there is disclosed an optical communication system in which an integrated service class may be applied in different packet rings for packet flows being forwarded through the different packet rings. A node device of the optical communication system extracts the inter-ring service class information contained in the inter-ring header information appended to a packet incoming from another packet ring. Based upon the so extracted inter-ring service class information, the node device refers to a table that has recorded the relationship of correspondence between the inter-ring service class and the intra-ring service class, as set between the packet rings, in order to decide on the intra-ring service class to be set for the incoming packet. The node device appends the intra-ring header information, inclusive of the so determined intra-ring service class information, to the incoming packet.
On the other hand, a technique termed source routing is known as a system that exercises route control in say an IP network. As set out in Non-Patent Document 2, the source routing is implemented by specifying an IP address of a relaying router.
In these days, a technique termed OpenFlow has been proposed, as indicated in Non-Patent Document 3. In OpenFlow, communication is grasped as end-to-end flow, and route control, restoration from malfunctions, load distribution and optimization are accomplished on the flow basis. An OpenFlow switch, operating as a forwarding node, includes a secure channel for communication with an OpenFlow controller, and is run in accordance with a flow table to which a command for addition or rewrite is given from time to time from an OpenFlow controller. In the flow table, a set of a rule (FlowKey), matched to a packet header, actions (Actions) that defines contents of the processing operation and the flow statistic Information (Stats) is defined from one flow to another (see FIG. 6).
FIG. 29 illustrates action names and contents of actions defined in Non-Patent Document 4. OUTPUT is an action for outputting to a specified port (interface). SET_VLAN_VID down to SET_TP_DST are actions that modify the fields of a packet header.
For example, the OpenFlow switch retrieves, on receipt of a first packet, an entry having a rule (FlowKey) matched to the header information of the received packet from the flow table. If, as a result of retrieval, an entry that fits with the packet received is found, the OpenFlow switch performs the contents of the processing operation, as set out in an action field of the entry, on the packet received. If conversely an entry that fits with the packet received is not found, the OpenFlow switch forwards the received packet over a secure channel to the OpenFlow controller to request the OpenFlow controller to decide on a route for the received packet based upon the source as well as the destination of forwarding of the received packet. The OpenFlow switch then receives a flow entry that implements the communication, while updating the flow table.    Patent Document 1:    JP Patent Kohyo Publication No. JP-P2006-513671A    Patent Document 2:    JP-Patent Kokai Publication No. JP-P2008-236652A

Communication system, node, control server, communication method and program


A originating terminal sends an ATM address interrogation request to a server if the ATM address of another party's terminal is unknown at the time of communication. Upon receiving the ATM address interrogation request from the terminal, the server refers to an ATM address table, searches the table for an ATM address corresponding to a protocol address contained in the interrogation request and notifies the originating terminal of this ATM address. If an ATM address corresponding to the protocol address has not been registered in the ATM address table, the server transfers (broadcasts) the ATM address interrogation request to all terminals. The server notifies the originating terminal of an ATM address obtained by an answer in response to this interrogation request and registers the ATM address in the ATM address table.

This invention relates to a communication system such as an ATM-LAN, a server and an address management method. More particularly, the invention relates to a communication system equipped with a plurality of terminals, a server having an ATM address table for storing the corresponding relationship between the protocol address and ATM address of each terminal, and an ATM exchange which accommodates each terminal and the server.
Improvements in the performance of personal computers and work stations have been accompanied by the rapid proliferation of applications for dealing with high-speed data and multimedia. In addition, such techniques as remote file access and decentralized computing have been established though use of LANS. For these reasons, there is expected to be greater demand for higher speed LANs for multimedia purposes.
In order to satisfy these expectations, there has been increased activity in the research and development of LANs (ATM-LANs) using ATM communication. An ATM-LAN is a switching LAN in which terminals are connected in a star-like configuration to an apparatus (an ATM exchange, for example) having an ATM switching function. Each terminal establishes a virtual channel (VC) directed toward a destination terminal and performs a data transmission by means of a fixed-length packet, referred to as an ATM cell, comprising a five-byte header and 48-byte data. As a result, it is possible to set a number of VCs on a terminal interface (where the number is capable of being expressed by the VPI/VCI) so that the terminal is capable of communicating with a plurality of other terminals simultaneously via the set VCs.
When communication is performed on a LAN, it is generally required that the originating terminal know the physical address of the terminal of the other party. In a conventional LAN, the physical address is a MAC address. Data in a LAN is transmitted in frame units, with each frame containing the addresses of the originating and terminating terminals. FIG. 21 is a diagram of a frame in a case where the protocol of a LAN is TCP/IP. The frame includes a start delimiter (SD) and an end delimiter (ED) between which are placed a destination address DA serving as a control field and a layer-2 address (MAC address), a sending address SA, an information field I (IP packet) and a frame scanning sequence FSC. The IP packet is subdivided into a control information field, a destination address DA′ serving as a protocol address (IP address), a sending address SA′ and an information field I′.
Communication with another terminal is not possible if the MAC address of the terminal is not known. If the MAC address of a party's terminal is unknown (but the protocol address is known), therefore, the original terminal determines the MAC address of the higher-order protocol address (IP address) by an address resolution protocol (ARP) and performs communication upon disassembling the higher-order packet (IP packet) into frames using the MAC address.
FIG. 22 is a processing flowchart of the ARP. If the MAC address of another party's terminal is unknown (NO at step S1), the originating terminal creates a frame (ARP frame) and sends the frame to the LAN (step S2). The ARP frame contains {circle around (1)} a broadcast address as the destination MAC address DA of the frame, {circle around (2)} a protocol address of another party's terminal serving as the destination protocol address DA′, and {circle around (3)} an indication that the frame is an ARP frame, this serving as control information CF′.
Upon receiving this ARP frame, each terminal determines whether the frame has its own address or is a broadcast frame. In this case, the frame is a broadcast frame and therefore the frame is accepted (step S11). Next, after verification of the fact that the frame is an ARP frame, each terminal determines whether the protocol address of the destination agrees with its own protocol address (step S12). Processing is terminated if the two addresses disagree. If the two addresses do agree, however, an answer frame which contains the terminals own MAC address is created at sent back to the originating terminal (step S13). Upon receiving the answer frame (YES at step S3), the originating terminal registers the correspondence between the MAC address of the other party's terminal contained in this answer frame and the protocol address in an internal IP-MAC address table (step S4) and then creates a frame (see FIG. 21) using the other party's MAC address and sends this frame to the LAN to perform LAN communication (step S5).
The foregoing is for the case of connection-less communication. In an ATM-LAN based upon connection-type communication, a VC is established between terminals and communication is performed while forming a higher-order packet into cells. In such an ATM-LAN, a physical address corresponds to the address (VPI/VCI) of the ATM layer, and this ATM layer address (VPI/VCI) is decided by a set-up sequence using the ATM address of the terminal. A set-up sequence is a call set-up processing sequence executed at the time of an outgoing call.
Thus, when the ATM address of the other party's terminal is unknown in an ATM-LAN, communication cannot be performed. This necessitates a method of analyzing the ATM address based upon the higher-order protocol address.
Conventional methods of acquiring the ATM address of another party's terminal include a broadcast method of broadcasting an interrogation request to all terminals and a server method of providing a server within the ATM-LAN and interrogating the server.
FIG. 23 is a diagram for describing the broadcast method. Terminals 1a, 1b, 1c are connected to an ATM-LAN 2. According to the broadcast method, the ATM address interrogation request is broadcast within the network if the ATM address of the other party's terminal is unknown at the moment a communication request is generated, and a prescribed terminal responds to this interrogation by answering with its own ATM address. For example, if the ATM address of terminal 1b is unknown to the terminal 1a when this terminal communicates with the terminal 1b in FIG. 23, the terminal 1a broadcasts an ATM address interrogation request cell (which has the protocol address of terminal 1b) within the network. The terminal 1b, which is that terminal having a protocol address identical with that contained in the received cell, answers the terminal 1a with its own ATM address. The terminal 1a uses the received ATM address to call the terminal 1b and communicate with it.
FIG. 24 is a diagram for describing the server method. FIG. 24 shows the terminals 1a, 1b, 1c and the ATM-LAN 2, which in this case is provided with a server 3. According to the server method, the corresponding relation between protocol addresses and ATM addresses of all terminals is registered in an ATM address table in advance. If the ATM address of another party's terminal is unknown at the moment a communication request is issued, an ATM address interrogation request is sent to the server and the server answers by retrieving the ATM address from the ATM address table. For example, if the ATM address of terminal 1c is unknown to the terminal 1a when this terminal communicates with the terminal 1c in FIG. 24, the terminal 1a sends the server 3 an ATM address interrogation cell (which has the protocol address of terminal 1c). The server 3 answers the terminal 1a by retrieving the ATM address of terminal 1c from the ATM address table, and the terminal 1a uses the received ATM address to call the terminal 1c and communicate with it.
If the ATM address of another party's terminal is unknown at the moment a communication request is issued in the broadcast method, a broadcast is made within the network and the terminal is interrogated directly. Unlike the server method, implementation is easy because it is unnecessary to create a data base in advance. However, in cases where frequent communication is made with an unspecified terminal whose ATM address is unknown, broadcast of the interrogation request is made whenever a communication request is issued. A problem which arises as a consequence is an increase in control traffic. This problem becomes particularly pronounced with an increase in the number of terminals or depending upon the scale of the network.
With the server method, on the other hand, there is no increase in traffic because there is no broadcast of an interrogation request. However, it is required that information (the correlation between protocol addresses and ATM addresses) regarding all terminals connected to the ATM-LAN be registered in the ATM address table in advance. At the time of initial installation therefore, it is necessary that the information regarding all terminals be registered in a data base (ATM address table) and that the data base be updated whenever a terminal is added on or moved. Further, an increase in the number of terminals or an increase in the scale of the network necessitates a data base of a larger capacity. This leads to an increase in the scale of the server hardware.

System for server obtaining terminal address via searching address table or via broadcasting to all terminals through exchange in response to terminal address interrogation request


Diesel engine particulate trap regeneration is obtained by concurrently supplying two exhaust gas streams to a particulate trap requiring regeneration. One stream is produced in a reactor/diesel engine operating an efficient stoichiometric ratio. The second stream is produced in a second reactor/diesel engine burning fuel at a low air/fuel ratio to produce an exhaust gas stream carrying a substantial load of unburned hydrocarbons, hydrogen and carbon monoxide. The two streams together carry sufficient thermal energy to ignite the unburned hydrocarbons, hydrogen and carbon monoxide using oxygen from the first exhaust gas stream as oxidizer.

1. Technical Field
The invention relates to regeneration of diesel exhaust particulate traps and more particularly, to a system and method for introducing heat, fuel and oxidizer to the particulate trap to induce combustion of particulate buildup.
2. Description of the Problem
Diesel engines generate unburned hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx), and particulates, and can pass molecular oxygen (O2) with the exhaust product. The particulate matter is principally solid particles of carbon and metal compounds with adsorbed hydrocarbons, sulfates and aqueous species. Among the adsorbed species are aldehydes (e.g. formaldehyde) and polycyclic aromatic hydrocarbons. Particulates, and carbon monoxide, are principally byproducts of incomplete combustion. Combustion in the engine can be modified to minimize particulate generation, however, doing so with contemporary technology leads to increases NOx emission.
Nitrogen oxides are also considered undesirable. NO is produced in large quantities at the high combustion temperatures which promote complete combustion and avoid particulate generation. NO2 is formed principally by the post oxidation of NO in the exhaust. NO2 production can be reduced by retarding engine timing and exhaust gas recirculation, both of which again contribute to particulate generation. Low emissions of nitrogen oxides also favor generation of CO and leave unburned hydrocarbons.
A currently favored approach to lowering diesel emissions is to accept increased particulate levels in the exhaust stream from the engine in order to reach the NOx targets, and to introduce a particulate trap to the exhaust stack to then remove the particulates and achieve the desired emission levels. Such traps can be constructed of metal or ceramics, and include a filter capable of collecting particulates from the exhaust stream. The trap must be able to withstand high temperatures, which are introduced to the traps periodically to oxidize particulate deposits which form in the traps. It has not proven easy to maintain traps at a sufficient temperature to burn the carbon deposits, especially where the traps are located a substantial distance from the engine compartment and downstream from exhaust energy recovery devices, such as power turbines for turbocharging systems. The problem is further complicated when the diesel is operating under a partial load. Secondary measures such as electrically powered heaters, which consume a great deal of power, have been built into particulate traps to address this problem. Particulate oxidation is further promoted by the injection of fuel into the exhaust stream which burns on contact with the heaters. This method of course increases fuel usage.
As part of tighter motor vehicle emission standards, commercial operators will be required to avoid long term idling of diesel engines. Extended idling has been a common practice for drivers who park their rigs for mandatory break periods and desire to have power for heating, cooling and entertainment while on break.

System and method for diesel particulate trap regeneration in a motor vehicle with an auxiliary power unit

International Truck Intellectual Property Company, LLC


A fully hermetically sealed semiconductor chip and its method of manufacture. The semiconductor chip of the present invention is fully hermetically sealed on both sides and the edges thereof through the use of suitable coatings applied thereto, such as glass, to prevent an environmental attack of the semiconductor chip. The fully hermetically sealed semiconductor chip of the present invention does not require the use of a separate package for the hermetic sealing of the chip, thereby reducing the size of such a chip. The method of the manufacture of the semiconductor chip of the present invention provides a simple process for the fully hermetic sealing of both sides and the edges of the semicondutor chip without the use of a separate package.

1. Field of the Invention
The present invention relates to hermetically sealed semiconductor chips. More specifically, the present invention relates to a fully hermetically sealed semiconductor chip and its method of manufacture.
2. Description of the Related Art
Solid state electronic devices, semiconductor chips, are typically manufactured from a semiconductor material, such as silicon, germanium, or gallium/arsenide. Circuitry is formed on one surface of the device with input and output pads being either formed around the periphery or generally in the center of the device to facilitate electrical connection.
The semiconductor chips are typically packaged to protect the chip from mechanical damage, external contamination, and moisture. Typical semiconductor chip packages may be divided into the broad categories of plastic encapsulated type, quasi-hermetic cavity type and fully hermetic cavity type. While plastic-encapsulation of semiconductor chips is the most common form of packaging chips, the plastic encapsulation allows the chip to be vulnerable to electrochemical processes. The numerous and extensive polymer/metal interfaces in the plastic encapsulated semiconductor package affords ample opportunities for moisture ingress as well as allowing the soluble ions present to provide an electrolyte for the corrosive failure mechanism of the semiconductor chip. Also, the extensive use of precious metals coupled with base metals in chips and packages provides dc galvanic potentials for electrochemical corrosion reactions and dendrite growth, thereby affecting the performance and life of the encapsulated semiconductor chip.
As a result of the problems associated with the plastic encapsulation of semiconductor chips, it is desirable to hermetically package chips to prevent external moisture and chemicals from contacting a chip. Hermetic packages for semiconductor chips generally are of the metal and ceramic material type. The common feature shared by these packages is the use of a lid or a cap to seal the semiconductor device mounted on a suitable substrate. The leads from the lead frame also need to be hermetically sealed. In metal packages, the individual leads are sealed into the metal platform by separated glass seals. In ceramic packages the leads are commonly embedded in the ceramic itself.
Several types of ceramic packages are used to hermetically seal semiconductor chips. Typically, such types of hermetic packages are ceramic dual-in-line package, hard glass package, side-brazed dual-in-line package, bottom-or top-brazed chip carrier, pin-grid array or other multilayer ceramic package. Some of such types of packages are described in U.S. Pat. Nos. 4,769,345, 4,821,151, 4,866,571, 4,967,260, 5,014,159, and 5,323,051.
However, such prior art type hermetically sealed packages for semiconductor chips all use an external package formed around the chip to form the hermetic seal. Such external packages increase the size and cost of the semiconductor chip for installation of the chip with associated circuitry.
While it is well known to attempt to seal semiconductor chip active circuitry at the wafer stage of production by applying a passivation coating to the wafer with ceramic materials such as silica and/or silicone nitride by CVD techniques, the subsequent etching back of the passivation coating at the bond pads of the semiconductor chip damages the passivation coating around the bond pads, thereby affecting the reliability of the chip and shortening the life of the chip from environmental corrosion as such chips are not truly hermetically sealed or considered to be fully hermetically sealed chips.
In an attempt to hermetically seal semiconductor chips without the use of external packages, in U.S. Pat. Nos. 4,756,977 and 4,749,631 it has been suggested to use lightweight ceramic protective coatings on such chips derived from hydrogen silsesquiozane and silicate esters as well as additional ceramic layers as hermetic barriers.
In another attempt to hermetically seal semiconductor chips without the use of external packages, as disclosed in U.S. Pat. No. 5,481,135, when certain ceramic protective coatings, such as those derived from hydrogen silsesquiozane and silicate esters, are applied to the active surface of a semiconductor chip at the wafer level, even though the bond pads are subsequently exposed by removing a portion of the ceramic protective coating, the resultant circuits remain hermetically sealed. However, the use of such ceramic protective coatings applied to the semiconductor chip at the wafer level are applied only to the active circuitry side of the wafer, not both sides of the wafer, nor on the edges of the semiconductor chips. As such, the semiconductor chip is not truly or fully hermetically sealed. At best, only one side of the semiconductor chip may be thought to be hermetically sealed, thereby leaving the other side of the chip unsealed as well as the edges of the chip.
None of the prior art hermetically sealed semiconductor chips described hereinabove are fully hermetically sealed without the use of a separate package, either metal or ceramic. A need exists for a fully hermetically sealed semiconductor chip which is fully hermetically sealed on both sides and the edges thereof without the use of a separate package.


Plastic rod anchorage for the surgical treatment of the spine where the plastic rod (1) has at least two plane-parallel surfaces (1a) in order to uniformly clamp the rod (1) on its entire circumference.

For stabilizing the spine, pedicle screws are inserted in the spine and their heads are interconnected by a rod. In order to maintain a dynamic behavior, elastic rods are known as an alternative to rigid metallic rods.
Since elastic rods are often manufactured from plastic materials, and plastic materials are generally susceptible to creep, plastic rods cannot simply be clamped by a press-fit as this is easily possible, for example, with metal rods.
Therefore, for a reliable long-term clamping of plastic rods (i.e. made of polymeric material), particular devices are required.
Only few methods to this end are known in the art so far. These will be explained below and their disadvantages as compared to the present invention will be pointed out.
The inventions according to patent specifications EP 1 364 622 B1 (Freudiger) and EP 1 527 742 B1 (Freudiger) show positive or form-fit anchorages. The rod and its seat in the screw head are provided with geometrically mutually fitting grooves. However, positioning the grooved surfaces requires precise introduction to avoid canting. Furthermore, grooved surfaces do not allow continuous positioning.
The invention according to patent specification EP 1 759 646 B1 (Freudiger) shows a frictional anchorage with an indirect form-fit. The connecting rod is smooth and is clamped between two members, the screw head and a laterally guided spacer, whose contour nominally deviates from the rod contour in the area of contact. Therefore, this nominal contour deviation locally penetrates into the rod such that high stress intensities result in the clamped areas and relative movements due to shear deformation in the non-clamped areas. Furthermore, rod material may flow off between the clamping areas if they do not form a closed cage.

Anchorage arrangement for a connecting rod for the stabilization of the spine


In accordance with an exemplary embodiment, a method of forming a dispersion-strengthened aluminum alloy metal includes the steps of providing a dispersion-strengthened aluminum alloy composition in a powdered form, directing a low energy density laser beam at a portion of the powdered alloy composition, and withdrawing the laser beam from the portion of the powdered alloy composition. Subsequent to withdrawal of the laser beam, the portion of the powdered alloy composition cools at a rate greater than or equal to about 106° C. per second, thereby forming the dispersion-strengthened aluminum alloy metal.

Aluminum base Al—Fe alloys have been developed that have mechanical properties comparable to titanium alloys up to temperatures of around 350° C. and can, because of their lower density—2.9 compared to 4.5 g/cc—result in significant weight savings in several applications. Although properties of these dispersion strengthened alloys are attractive, applications have been restricted, due to the complexity of the fabrication process required to make useful shapes. The benefits that could potentially be derived through use of such alloys have heretofore been offset by the cost of fabricating the alloys into useful shapes.
It is difficult and expensive to manufacture components with these advanced aluminum base Al—Fe alloys because a multi-step process is required that includes rapid solidification ribbon casting, ribbon pulverizing, powder canning, HIP, extrusion, and forging to generate and maintain the unique microstructure and material properties of the alloy. FIG. 1 illustrates this process. The need for extensive hot working by extrusion and forging also limits the size and complexity of parts that can be practicably produced from the alloy.
Accordingly, it is desirable to provide improved methods for forming dispersion strengthened aluminum alloys. Further, it is desirable to provide such methods that do not require ribbon casting. Furthermore, other desirable features and characteristics of the invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.

Methods for forming dispersion-strengthened aluminum alloys


A heat spreader and package structure utilizing the same. The heat spreader is embedded in an encapsulant of a package and above a chip therein, wherein the package has a substrate, having a molding gate, and the chip has a center and a corner which is the farthest from the molding gate. The spreader includes a base with a hollow portion therethrough, a plurality of support leads, protruding from the base, on the inner edge, and a cap plate, having a hole at least directly above a region between the center and the corner of the chip, fixed by the support leads to be above the hollow portion, the cap plate.

This application is a Divisional of copending application Ser. No. 11/073,676 filed on Mar. 8, 2005 now U.S. Pat. No. 7,190,066 the entire contents of which are hereby incorporated by reference and for which priority is claimed under 35 U.S.C. § 120.
The invention relates to a package structure, and more specifically to a package structure with improved reliability.
As semiconductor device circuit density increases and device feature size decreases, increased numbers of patterned metal levels are required with decreased spacing between metal lines at each level to effectively interconnect discrete devices on semiconductor chips. Layers of insulating materials or films, typically referred as inter-layer dielectric (ILD) layers, separate different levels of metal interconnections. A common insulating material used for ILD layers is silicon oxide having a dielectric constant (k) of about 4.0 to 4.5 relative to vacuum having a k value of 1.0. Unfortunately, as the spacing between the metal lines decreases, the intra-level and inter-level capacitances therebetween increases, as capacitance is inversely proportional to the spacing therebetween. It is therefore desirable to minimize the dielectric constant k of the insulating material between the metal lines to reduce the RC time constant, and thus, the performance of the circuit, e.g., the frequency response or the like, is improved since the signal propagation time in the circuit is adversely affected by the RC delay time.
When an insulating material having a dielectric constant k less than 3, often referred to as a low k material, is utilized as ILD layers between the metal lines, the adhesion between the low k material and metal line, however, is weaker than that between silicon oxide and metal line. Further, the linear thermal expansion coefficient of a conventional encapsulant for a package is typically larger than 10 ppm/° C., and that of silicon, one of the popular semiconductor materials, is approximately 3 ppm/° C. Thus, high thermal expansion coefficient mismatch therebetween results in exertion of thermal stress between a chip and encapsulant in the package. When a low k material is used for ILD layers in the chip, the ILD layers suffer more potential of delamination resulting from the exertion of thermal stress during assembly.

Heat spreader and package structure utilizing the same

Taiwan Semiconductor Manufacturing Co., Ltd.


A distal protection device captures debris during vascular procedures. In order to reduce the profile of the device, the thickness of the distal protection element is reduced in one or both of the end regions, either by reducing the thickness of filaments which form the distal protection element, or by removing portions of those filaments altogether. Various methods of reducing the thickness of the end regions and different profiles that can be created by the reduction are disclosed.

1. Field of the Invention
The present invention relates generally to endovascular devices for capturing particulate during vascular procedures and methods for making same. More particularly, the invention relates to a distal protection element located at the distal end of a delivery member prevent emboli in a blood vessel from moving away from the treatment site during a vascular procedure. The distal protection element is comprised of filaments, some of which have been reduced in thickness during manufacture of the device, so that the device has a low collapsed profile and greater flexibility in the end regions.
2. Related Art
A variety of treatments exist for compressing or removing athersclerotic plaque in blood vessels. The use of an angioplasty balloon catheter is common in the art as a minimally invasive treatment to enlarge a stenotic or diseased blood vessel. This treatment is known as percutaneous transluminal angioplasty (hereinafter, "PTA"). To provide radial support to the treated vessel in order to prolong the positive effects of PTA, a stent may be implanted in conjunction with the procedure.
Thrombectomy is a minimally invasive technique for removal of an entire thrombosis or a sufficient portion of the thrombosis to enlarge a lumen of a stenotic or diseased blood vessel and may be accomplished instead of, or in addition to, a PTA procedure. Atherectomy is another well-known minimally invasive procedure that mechanically cuts or abrades a stenosis within a diseased portion of the vessel. Alternatively, ablation therapies use laser or RF signals to superheat or vaporize the thrombosis within the vessel. Particulate debris loosened during such procedures may be removed from the patient through the catheter.
During each of these procedures, there is a risk that particles dislodged by the procedure will migrate through the circulatory system to embolize distally and cause infarction or strokes. Thus, practitioners have approached prevention of escaped emboli through use of distal protection elements such occlusion devices and filters as well as lysing and aspiration techniques. For example, it is known to remove the particulate material by suction through an aspiration lumen in the treatment catheter or by capturing debris in a filter or occlusion device positioned distal of the treatment area.
Prior art temporary distal protection elements such as filters or occlusion devices are associated with either a catheter or guidewire and are positioned downstream of the area to be treated. One prior art filter arrangement includes a dilatation balloon and a filter mounted on the same catheter. The filter is located distal to the dilatation balloon and consists of a filter material secured to resilient ribs. A filter balloon is located between the catheter exterior and the ribs. Inflation of the filter balloon extends the ribs outward across the vessel to form a trap for fragments loosened by the dilatation balloon. When the filter balloon is deflated, the resilient ribs retract against the catheter to retain the fragments during withdrawal of the catheter.
Another prior art device provides an expandable occlusion member mounted on a slender, elongate wire. The occlusion member is placed distal to the intended treatment site and expanded to obstruct the flow of bodily fluids during the procedure. An interventional catheter is guided to the treatment site over the wire and the vessel narrowing is enlarged. Any emboli produced are trapped upstream of the occlusion balloon. Bodily fluid containing the particulate is aspirated from the vessel, either through a dedicated lumen in the treatment catheter, or via a separate aspiration catheter that has been exchanged for the treatment catheter. The occlusion member is then collapsed and removed from the patient. The occlusion member may be an inflatable balloon or a mechanically expandable structure covered by a non-porous membrane.
Another prior art device includes a filter mounted on the distal portion of a hollow guidewire or tube. A moveable core wire is used to open and close the filter. The filter is secured at the proximal end to the tube and at the distal end to the core wire. Pulling on the core wire while pushing on the tube draws the ends of the filter toward each other, causing the filter framework between the ends to expand outward into contact with the vessel wall. Filter mesh material is mounted to the filter framework. To collapse the filter, the procedure is reversed, i.e., pulling the tube proximally while pushing the core wire distally to force the filter ends apart.
Another prior art device has a filter made from a shape memory material. The device is deployed by moving the proximal end of the filter towards the distal end. The filter is collapsed by sliding a sheath over the filter and then withdrawn by removing the sheath and filter together.
Another prior art filter device includes a compressible polymeric foam filter mounted on a shaft that is inserted over a guidewire. The filter is inserted in a collapsed state within a housing which is then removed to deploy the filter once in position. The filter is retracted by inserting a large bore catheter over the shaft and the filter and then removing the shaft, filter and catheter together.
Another prior art filter arrangement has a filter comprised of a distal filter material secured to a proximal framework. This filter is deployed in an umbrella manner with a proximal member sliding along the shaft distally to open the filter and proximally to retract the filter. A large separate filter sheath can be slid onto the shaft and the filter can be withdrawn into the sheath for removal from the patient.
Other known prior art filters are secured to the distal end of a guidewire with a tubular shaft. Stoppers are placed on the guidewire proximal and distal of the filter, allowing the filter to move axially independently of the guidewire. Sheaths are used to deploy and compress the filter.
One problem with known filter arrangements is that the capture element has a large profile as measured at the distal and proximal end regions thereof. The large profile of the collapsed capture element creates stenosis-crossing problems and possible snagging as the capture element is withdrawn through a stent. In addition, the force required to pull the capture element back into the retrieval sheath is greater than that which would be required if the capture element had a smaller profile. In particular, the braided element is too thick at the end regions under the marker bands. Further, the braided element is too thick in the tapered portion of the end regions, causing these regions to resist lying snugly about the guidewire when collapsed. In other words, the end regions may bulge outwardly instead of collapsing flatly against the core wire.
The main factor contributing to the enlarged profile of the filter or capture element is the thickness of the filaments used to form the filter. The profile is increased in part because the filaments are grouped together in a relatively small area for connection to the core wire and the thickness of the filaments prevents an appropriate reduction in profile.