The present invention is directed to hemostatic material containing compacted ORC powder comprising particles having an average aspect ratio from about 1 to about 18, wherein said compacted ORC powder have preferably been processed in a compaction device, such as a ball milled ORC powder. The present invention further relates to methods of making the hemostatic material and a method of treating a wound by applying the hemostatic powder onto and/or into the wound of a patient.

In a wide variety of circumstances, animals, including humans, can suffer from bleeding due to wounds or during surgical procedures. In some circumstances, the bleeding is relatively minor, and normal blood clotting functions in addition to the application of simple first aid are all that is required. In other circumstances substantial bleeding can occur. These situations usually require specialized equipment and materials as well as personnel trained to administer appropriate aid.
In an effort to address the above-described problems, materials have been developed for controlling excessive bleeding. Topical Absorbable Hemostats (TAHs) are widely used in surgical applications. TAHs encompass products based on oxidized cellulose (OC), oxidized regenerated cellulose (ORC), gelatin, collagen, chitin, chitosan, etc. To improve the hemostatic performance, scaffolds based on the above materials can be combined with biologically-derived clotting factors, such as thrombin and fibrinogen.
The control of bleeding is essential and critical in surgical procedures to minimize blood loss, to reduce post-surgical complications, and to shorten the duration of the surgery in the operating room. Due to its biodegradability and its bactericidal and hemostatic properties, oxidized cellulose, as well as oxidized regenerated cellulose has long been used as a topical hemostatic wound dressing in a variety of surgical procedures, including neurosurgery, abdominal surgery, cardiovascular surgery, thoracic surgery, head and neck surgery, pelvic surgery and skin and subcutaneous tissue procedures. A number of methods for forming various types of hemostats based on oxidized cellulose materials are known, whether made in powder, woven, non-woven, knit, and other forms. Currently utilized hemostatic wound dressings include knitted or non-woven fabrics comprising oxidized regenerated cellulose (ORC), which is oxidized cellulose with increased homogeneity of the cellulose fiber. Examples of such hemostatic wound dressings commercially available include SURGICEL® resorbable hemostat; SURGICEL® NU-KNIT® resorbable hemostat; SURGICEL® FIBRILLAR resorbable hemostat, and SURGICEL® SNoW™ resorbable hemostat; all available from Johnson & Johnson Wound Management Worldwide, a division of Ethicon, Inc., Somerville, N.J., a Johnson & Johnson Company. Other examples of commercial resorbable hemostats containing oxidized cellulose include GelitaCel® resorbable cellulose surgical dressing from Gelita Medical BV, Amsterdam, The Netherlands. The commercially available oxidized cellulose hemostats noted above are knitted or nonwoven fabrics having a porous structure for providing hemostasis.
U.S. Pat. No. 3,364,200 to Ashton and Moser describes a resorbable, surgical hemostat in the form of pledgets of integrated oxidized cellulose staple fibers.
Published U.S. Patent Application Publication 2008/0027365 to Huey describes an apparatus for promoting hemostasis utilizing oxidized cellulose in the form of a compressible, shapeable mass that is formed into a sheet for placement on a bleed site and further having a sleeve in a form of a tubular shell dimensioned to receive a limb.
Published U.S. Patent Application Publication 2004/0005350 to Looney et al. discloses hemostatic wound dressings utilizing a fibrous fabric substrate made from carboxylic-oxidized cellulose and containing a porous, polymeric matrix homogeneously distributed through the fabric and made of a biocompatible, water-soluble or water-swellable cellulose polymer, wherein the fabric contains about 3 percent by weight or more of water-soluble oligosaccharides.
Patent publication WO 2007/076415 by Herzberg et al. and entitled "COMPOSITIONS AND METHODS FOR PREVENTING OR REDUCING POSTOPERATIVE ILEUS AND GASTRIC STASIS", discloses milling of ORC, particularly cryogenic milling, using a cutting blade of a motor-driven mill.
An article titled "The Ball-Milling of Cellulose Fibers and Recrystallization Effects", Journal of Applied Polymer Science, Volume 1 Issue 3, Pages 313-322, (1959) by Howsmon and Marchessault, reports results of a study of the effect of fine structure on the decrystallization process which results from the ball-milling of cellulose. The rate of decrystallization is sensitive to the type of fine structure and is accelerated by the presence of moisture. The extent of chain degradation was greater in air atmosphere than in carbon dioxide, suggesting that mechanically induced free radical degradation occurs along with other chain-breaking processes. A study of the density and moisture regain of the samples after various times of milling showed that a linear relation between regain and density held over the entire range studied. The relation was the same for native and regenerated cellulose. The process of recrystallization of the ball-milled samples was studied under various conditions and compared to the hydrolytically induced recrystallization of rayons. The reference discloses effect of fine structure on the decrystallization process which results from the ball-milling of cellulose fibers.
U.S. Pat. No. 6,627,749 discloses a process for grinding oxidized cellulose using a pestle and mortar or in a ball mill or any other conventional laboratory grinder. It further discloses that when cotton linter sheet is used as the starting cellulose source, the fiber length of the product decreases with increasing reaction time. When ball-milled, the long fibrous structures of the product turn into smaller fibers, to loosely-packed spherical aggregates. No significant change in the crystallinity of these samples occurs as a result of ball milling. The reference discloses long fibrous oxidized cellulose ball milled to form small fibers or loosely packed spherical aggregates.
Other related references include: U.S. Pat. No. 6,309,454, Freeze-dried composite materials and processes for the production thereof; U.S. Pat. No. 5,696,191; U.S. Pat. No. 6,627,749; U.S. Pat. No. 6,225,461 to Kyoko et al.; PCT patent publication WO2001/024841 A1, Compositions for the Treatment of Wound Contracture; and European patent publication EP1,323,436 to Dae Sik et al.
Other related references include: An article titled "The role of oxidized regenerated cellulose/collagen in chronic wound repair and its potential mechanism of action", The International Journal of Biochemistry & Cell Biology 34 (2002) 1544-1556, Breda Cullen et al.; an article by Rangam et al. teaching methods of making silk powders through milling processes [Powder Technology 185(2008), p 87-95]; an article by Yasnitskii et al., Oxycelodex, a new hemostatic preparation, Pharmaceutical Chemistry Journal, 18, 506-5; discloses an Oxycelodex paste that consists of two components, oxidized cellulose powder and a 20% aqueous solution of dextran.
U.S. Patent Application 2006/0233869 to Looney et al. discloses using a chopping/shredding process to make ORC micro-fibers from ORC fabrics. The rod-like shaped fibers had sizes which ranged from about 35 to 4350 micrometers.

This patent is subject to a terminal disclaimer.

Oxidized regenerated cellulose hemostatic powders and methods of making


When the applied voltages are 7 V and 5 V, a transmittance of equal to or more than 50% is obtained when conditions of |2Ps·A|≦|7Clc·A| and |2Ps·A|≦|5Clc·A| are satisfied among the magnitude Ps (nC/cm2) of the spontaneous polarization per unit area of the liquid crystal material, the electrode area A (cm2) of the pixels and the capacity of liquid crystal Clc (nF/cm2) per unit area, and a transmittance of equal to or more than 80% is obtained when conditions of |2Ps·A|≦|4.5Clc·A| and |2Ps·A|≦|3Clc·A| are satisfied thereamong. A sufficiently high transmittance is obtained without the provision of a storage capacitor.

With the recent progression of the so-called information-oriented society, electronic apparatuses typified by personal computers and PDAs (personal digital assistants) have come to be widely used. The spread of such electronic apparatuses has produced a demand for portable apparatuses that can be used both in offices and outdoors, and such apparatuses are required to be reduced in size and weight. As a means of achieving this object, liquid crystal display devices are widely used. Liquid crystal display devices are an indispensable technology not only for the reduction in size and weight but also for the reduction in the power consumption of battery driven portable electronic apparatuses.
Liquid crystal display devices are broadly classified into a reflective type and a transmissive type. The reflective type has a structure in which the light incident from the front surface of the liquid crystal panel is reflected at the back surface of the liquid crystal panel and the image is made visually seen by means of the reflected light. The transmissive type has a structure in which the image is made visually seen by means of the transmitted light from a light source (backlight) provided on the back surface of the liquid crystal panel. Since the reflective type in which the amount of reflected light varies depending on the environmental condition is inferior in viewability, transmissive type color liquid crystal display devices using color filters are generally used as display devices, particularly, for personal computers and the like that perform multi-color or full-color display.
At present, active driven type liquid crystal display devices using switching elements such as TFTs (thin film transistors) are widely used as color liquid crystal display devices. In the TFT driven liquid crystal display devices, although the display quality is high, since the light transmittance of the liquid crystal panel is only approximately several percents under present circumstances, a high-brightness backlight is necessary to obtain high screen brightness. For this reason, the power consumption of the backlight is increased. In addition, since color filters are used for color display, one pixel is necessarily formed of three subpixels, so that high resolution is difficult to achieve and the display color purity is insufficient.
To solve this problem, the present inventor et al. have developed field sequential type liquid crystal display devices (see, for example, Non-Patent Documents 1, 2 and 3). In the field sequential type liquid display devices, compared with the color filter type liquid crystal display devices, since no subpixel is required, higher-resolution display can be easily realized, and since the luminous colors of the light source can be used for display as they are without the use of color filters, the display color purity is excellent. Further, since light use efficiency is high, power consumption is low. However, to realize the field sequential type liquid crystal display devices, it is essential that the liquid crystal have a fast responsivity (equal to or less than 2 ms).
Accordingly, to achieve a fast responsivity in the field sequential type liquid crystal display devices having excellent advantages as mentioned above or the color filter type liquid crystal display devices, the present inventor et al. have researched and developed the driving of a liquid crystal such as a ferroelectric liquid crystal having spontaneous polarization from which a fast responsivity 100 to 1000 times that of conventional devices can be expected, by switching elements such as TFTs (see, for example, Patent Document 1). In the ferroelectric liquid crystal, the direction of major axis of the liquid crystal molecules tilts by voltage application. A liquid crystal panel holding the ferroelectric liquid crystal is sandwiched between two polarizers the polarization axes of which are orthogonal to each other, and the transmitted light intensity is changed by using the birefringence caused by the change of the major axis direction of the liquid crystal molecules.    [Patent Document 1] Japanese Patent Application Laid-Open No. H11-119189    [Non-Patent Document 1] T. Yoshihara et al., ILCC 98, P1-074, issued in 1998    [Non-Patent Document 2] T. Yoshihara et al., AM-LCD'99 Digest of Technical Papers, p. 185, issued in 1999    [Non-Patent Document 3] T. Yoshihara et al., SID'00 Digest of Technical Papers, p. 1176, issued in 2000

Liquid crystal display device having spontaneous polarization


Disclosed are a new silicone cold-extrusion lamp belt and its manufacturing method. The manufacturing method includes the following steps. S10: Select a PCB and use the PCB as a substrate. S20: Set LED lamp bead spot-welding units arranged in an array formed on the substrate to obtain a target board. S30: Extrude a slurry which is formed by a food-grade silicone and coat the slurry on an outer surface of the target board to form a lamp skin. S40: Cut the target board into at least one lamp belt substrate. S50: Heat and bake the lamp belt substrate to obtain a lamp belt. This disclosure has the advantages of feasible design, low manufacturing cost, high resistance on cracking, wearing, yellowing, high/low temperature, good fire resistance, environmental friendly and harmless to human safety, high transparency, high light emitting efficiency of the lamp, and applicable for indoor/outdoor lamp belts.

At present, the skin of a conventional lamp belt is made of two main types of materials, respectively: general industrial silicone and industrial PU plastic. In actual application, the products made of these two materials have the issue of having a short life cycle or an easily cracked or yellowed surface after a long time of use. In addition, most skins of the lamp belt made of these two types of materials generally have the shortcomings of low fire resistance, poor high/low temperature resistance, bad smell, easily flammable PU plastic material, and black smoke produced during combustion. Therefore, the lamp belt products made of the aforementioned two materials have limited flexibility on the appearance of the lamp belt.
Obviously, the conventional lamp belt requires improvements.

Silicone cold-extrusion lamp belt and manufacturing method thereof

Shenzhen Thousandshores Technology Co., Ltd.


An object, such as a robotically controlled television camera undergoes alignment with a reflective target by directing a coherent beam of radiation, e.g., a laser beam, into an opening in an enclosure having a reflective interior such that the radiation strikes a reflector in axial alignment with the enclosure opening. Upon striking the target, the beam undergoes reflection through the enclosure opening back to the object for detection. Alignment between the object and the target occurs when substantially all of the radiation undergoes reflection from the target to the object.

In many applications, a need exists to establish alignment of an object with a target. For example within a television studio, movement of a tripod or pedestal associated with a television camera to an alternate locations often occurs to better leverage the investment in such equipment. However, a change in the positioning of the tripod or pedestal with respect to the set often results a change in the camera position. As a consequence, the new position of the camera will likely differ by several centimeters, or even several meters from its previous position (referred to as a "preset"). In the case of a robotically operated camera, no mechanism typically exists for easily accomplishing re-alignment. Rather, the camera must undergo manual re-alignment and followed by time consuming re-programming of the location presets.
Thus a need exists for a technique for simply and efficiently aligning a television camera.


A charge air cooler assembly for an internal combustion engine is described. A housing of the charge air cooler assembly includes a dividing wall that separates flow after the charge air cooler into two separate flow paths.

High speed, which may be 1200 to 1800 rpm, natural gas engines in industrial applications such as gas compression and power generation producing 500 kW to several megawatts of shaft power are typically turbocharged and intercooled and often employ twelve or more cylinders arranged in a "V" configuration. This configuration results in a large volume of combustion gases in the intake system, especially on engines where the intake manifold is on the outboard side of the "V." Gaseous fuel may be introduced into the air stream at the inlet of the compressor, resulting in a highly combustible air-fuel mixture throughout the entire intake system. This mixture has the potential to ignite in the intake system upon encountering an ignition source such as a combustion gas from an improperly seated intake valve. Once the air-fuel mixture ignites, the flame will travel extremely rapidly toward the charge air cooler, crossing over into the opposite intake manifold, thus igniting a substantial volume of fuel and leading to an intake manifold overpressure event, which may be called a backfire, that significantly exceeds typical operating pressures.
A variety of countermeasures have been employed in these engines to withstand potential overpressure, including building the intake manifold with sufficient thickness and material to withstand to accommodate potential overpressure. A flame arrestor may also be part of such engines to quench flames.
Other techniques have been used in an attempt to eliminate or reduce overpressure events. For example, the use of timed port injection of fuel, with a solenoid at the intake port of every cylinder a short distance upstream of the intake valves. Fuel injection takes place only when the exhaust valves are closed and the intake valves are open. This technique significantly reduces the volume of the air-fuel mixture in the intake manifold, which reduces the likelihood of intake manifold overpressure. While this configuration is often used on medium speed gas engines, this configuration adds significant cost and complexity and is seldom used on high-speed gas engines. Furthermore, such events can still occur, such as when an injector malfunction results in a continuous stream of fuel.
Another technique to reduce intake manifold overpressure is to reverse the location of the intake and exhaust manifolds, so that the intake manifold is inside the "V"-bank and the exhaust manifold is on the outboard side. This configuration significantly reduces the volume and length of the intake manifold, thus minimizing intake manifold overpressure intensity from combustion of the air-fuel mixture. While some engines are capable of using this configuration, other engine configurations do not permit reversing the location of the intake and exhaust manifolds without significant redesign of the engines, potentially compromising operational characteristics and leading to substantial cost burden.
An array of pressure relief valve or burst disks may also be located in strategic locations around the intake manifold. However, in addition to added cost, pressure relief valves may not reseal and burst disks need replacement after an intake manifold overpressure event. Such devices have also been inconsistent in actual operation with variations in actuating pressure, potentially still permitting excessive intake manifold overpressure events.
Some engines may incorporate a combination of such elements. Regardless of the countermeasures incorporated, the possibility of an intake manifold overpressure event is always present in natural gas engines, especially on engines where fuel is introduced significantly upstream of a cylinder's intake ports.
Thus, there is a need to reduce the severity of fuel ignition events should they occur and limiting the extent of such events.


A method for calibrating a tool control frame (TCF) on a robot with respect to a known calibration reference claim (CRF), wherein the (CRF) is in rigid body relationship with a robot link. The method includes the steps of (a) attaching a sensory tool to the robot link, (b) calibrating the sensory tool with appropriate units of measurement, (c) identifying a calibration feature to be mapped by the sensory tool, (d) causing relative movement of the calibration feature within sensing range of the sensory tool, (e) recording robot configuration and pose as a first data record, (f) causing relative movement of the calibration feature and sensory tool along a known direction to a new position within sensing range, (g) recording configuration and pose as a second data record, and (h) applying coordinate transformations to the respective data records to generate a correct tool control frame (TCF) pose with respect to the (CRF).

1. Field of the Invention
This invention pertains to methods and devices for enabling off-line programming of robot tasks. More particularly, the present invention relates to a method of mapping and correcting for robot inaccuracy.
2. Prior Art
Robot mechanisms are being increasingly used within the manufacturing industry for performing repetitive tasks in an assembly line configuration. In recent years much emphasis has been placed on robot off-line programming. The benefits of a true off-line system are substantial. Off-line programming and robot task simulation allow the user to verify robot tasks before purchasing costly equipment, thus insuring that the proper robot has been chosen for the task.
When several robots are to perform the same or similar task, off-line programming allows the task to be planned once, with the resulting program being applied to each separate robot. Minor changes in a robot's program are then easily handled without the customary down-time of on-line programming. When properly coupled with robot sensor systems, off-line programming can put the flexibility into robot workcells that has long been promised, but seldom realized.
Such flexibility could allow robot systems to respond to task operations that have heretofore been uneconomical such as "Parts on Demand" manufacturing schemes and random part presentations. If parts are allowed to arrive at robot workcells with random position and/or orientation, much of the need for costly jigs and fixturing could be eliminated. Such fixturing is not only expensive, but very time consuming. It represents one of the major hurdles against making robot workcells flexible.
Although off-line programming offers many benefits, industry has been slow to adopt this method of workcell operation. A major reason for minimal progress has been the inadequacy of compensation and control of robot inaccuracy. Commercial off-line programming packages show beautifully animated models of robot workcells simulated on engineering graphics workstations, but when the final product is down-loaded to the robot workcell, the robot is unable to perform the desired task with sufficient accuracy to be useful. The result is that, although the logic of a robot program can be developed off line, the actual robot configurations must be retaught on-line in a traditional teach pendant mode.
To further compound the problem, some robot configurations simply cannot be taught with a teach pendant system. An example of such a configuration is the placement of a part relative to some established datum but where no physical markings are available to guide the robot programmer. In this instance, the ability of the robot to move accurately is imperative to the ability of the robot to perform the task.
An understanding of the problems of accuracy and repeatability will be helpful for an appreciation of the solution presented by the invention disclosed herein. The concept of "repeatability" centers on the ability of a robot to move to the same position time after time, always within acceptable tolerances. "Accuracy", on the other hand, is the ability to directly move to a desired position upon an absolute command. By way of illustration, a repeatable archer will always shoot arrows in a very tight pattern on his target. However, this repeatability will be of little value unless that tight pattern is accurately near the bullseye.
Quality robot mechanisms are generally very repeatable in that they can consistently retrace movement patterns. Unfortunately, most robots are inherently inaccurate. This inaccuracy may be categorized in four major areas:
1. Robot technical imperfections PA0 2. Robot tool calibration error PA0 3. Rigid body error PA0 4. Robot tip deflections due to load
The technical imperfections stem from both the manufacturing processes resulting in tolerance stackup, joint misalignments, etc., and from natural wear of mechanical parts such as bearings. This is controlled by careful machine and design work. Robot tool calibration error is the result of not knowing where a robot's tool control frames (referred to herein as the TCF) are located relative to the robot's link frame. This is discussed in greater detail hereafter.
The third category of rigid body error is not really robot inaccuracy, but since the resulting error is the same, it is often grouped with robot inaccuracy. It is actually the error associated with not knowing the exact location of the parts that the robot is to operate on relative to the robot's base frame. The final category of "tip deflections" is obviously a function of load control and is controlled by task operation planning and engineering design of the robot load capacity.
The traditional solution to the inaccuracy issue is the teach pendant. The teach pendant circumvents the inaccuracy issue by relying on the inherent repeatability of robots. When a robot is taught a configuration using a teach pendant, it usually stores the encoder values of each joint motor at the desired robot configuration (a measurement of how many revolutions the motor has made from some known zero position). To return to that configuration, the robot need only command each motor to return to those saved encoder values. The robot need not even know where its tool is located in space, nor the part. Consequently, even inaccurate robots are often very repeatable.
However, teach pendant has little flexibility. If the robot is able to return to its exact prior position, but the part has not been positioned exactly, the robot may be useless. Accordingly, when a robot is programmed off-line, the luxury of a teach pendant is lost. Instead of repeatability , the programmer must now rely on accuracy. At first this may appear to be a great liability, and indeed has been a complication for off-line programming; however, development of a method to command robot accurately in an off-line mode can quickly convert this liability to an asset.
An earlier attempt to resolve this "accuracy" problem associated with tool calibration was developed by several of the present inventors and is disclosed in U.S. Pat. No. 4,831,549. In addition to giving a more complete review of prior art robot programming (incorporated herein by reference), this patent taught the use of a pointer tool as the solution to accurate calibration for the location and orientation of tools and sensors attached to the robot. The method involved defining a relationship between the last joint frame LJF and the pointer tool. A stylus associated with the tool was carefully lined up with the z axis of the LJF. The stylus was then moved to a known feature such as a grid marking on a template. This was identified as point one. The position of the robot with the stylus at this location was then recorded. Each tool to be calibrated was then moved to this exact position at point one and the respective robot configurations were again recorded. The difference between the stylus position and the respective tool positions provided the offset values to correct inaccuracy. Multiple points were used to develop a statistical average of these x and y offsets. The z axis was likewise measured by determining tool height.
These methods for tool and sensor calibration were demonstrated to work, even in the presence of robot inaccuracy and operator visual positioning error, due to the statistical method applied. The disadvantages of the previous technology are that it is tedious and time consuming, and is subject to the operator's visual acuity, which limits its application in the manufacturing environment. To obtain good statistical accuracy, ten to twenty points would have to be processed. This involved meticulously jogging or moving the stylus to these respective exact points on the template, so that the stylus and point were in exact alignment. Then each of the tools had to be similarly moved, with robot configurations appropriately recorded. This method required hours of tedious effort, and could take days where multiple tools required calibration.
What was needed therefore, was an improved method and device which did not require the tedious alignment of a stylus with a calibration feature such as the referenced point on a template, but instead would involve a simple system of movements without the need for critical alignment.

Robot end-effector terminal control frame (TCF) calibration method and device


A multifocal representation device with a digital image generation module and a control unit, which conveys to the digital image generation module two-dimensional image data of a three-dimensional object to be represented, is provided, wherein the digital image generation module, based on the two-dimensional image data conveyed, generates two-dimensional images of the object from at least two different object planes in corresponding different focal planes in such a way that an observer can focus with his eye on the different focal planes in order to perceive the represented object three-dimensionally, and wherein the control unit determines for each two-dimensional image to be represented a sharpness value in sections and sets the image data to dark for the image sections the sharpness value of which lies outside a sharpness value range predetermined for the image.

Conventional multifocal representation devices and conventional multifocal representation methods disclosed in U.S. Pat. No. 5,880,711. As the two-dimensional images are generated in at least two different focal planes, for an observer the contrast drops in comparison with the representation of a single image, wherein the reduction in the contrast increases sharply with the number of focal planes.

Multifocal representation device and multifocal representation method for the three-dimensional representation of an object


A powder conveyance unit, providable to an image forming apparatus, includes a path forming member configured to form a powder conveyance path including an inner wall to convey powder therethrough and connect first and second powder containers, and a substantially planar plate-like powder remover configured to remove powder adhering to the inner wall of the powder conveyance path. The plate-like powder remover is disposed in the powder conveyance path with both lateral edges thereof in a width direction perpendicular to a powder conveyance direction in the powder conveyance path contacting or nearly contacting the inner wall of the powder conveyance path. Opposed flat surfaces of the plate-like powder remover moves reciprocally between opposed surfaces of the inner wall of the powder conveyance path to remove powder adhering to the surfaces of the inner wall of the powder conveyance path.

1. Field of the Invention
Illustrative embodiments of the present invention generally relate to a powder conveyance unit and an image forming apparatus including the powder conveyance unit, and more particularly, to a powder conveyance unit for conveying powder such as toner, and an image forming apparatus such as a printer, copier, and facsimile machine for forming images with the powder.
2. Discussion of the Related Art
Related-art image forming apparatuses generally include a developing unit, in which developer, containing mainly toner but also carrier particles, is accommodated to develop a latent image formed on an image carrier into a visible image.
Since toner contained in the developer is constantly consumed when developing images whereas the carrier is not, new or unused toner may need to be additionally supplied to the developing unit. Such new or unused toner is conveyed from a toner container provided in the apparatus to the developing unit so as to replenish the developer in the developing unit.
Such related-art image forming apparatus further includes a cleaning unit that collects residual toner remaining on the image carrier after transfer of the toner image from the image carrier to a transfer member. The residual toner collected by the cleaning unit is conveyed to and collected in a waste toner collecting unit or the developing unit for reuse and recycling.
An image forming apparatus that employs a known technique conveys free-falling toner from a toner container to a developing unit via a toner conveyance path in a toner conveyance unit therein. In such a toner conveyance unit, toner particles can adhere to small or narrow gaps or uneven portions on inner walls of a toner conveyance path forming member that forms the toner conveyance path and thus remain in the toner conveyance path after conveyance of toner. The toner particles adhering to the inner wall as described above accumulate with time and become firmly fixed to the inner walls due to changes in ambient temperature and/or humidity in the image forming apparatus. Accumulation of toner particles on the inner walls of the toner conveyance path makes the toner conveyance path narrower, which can cause toner to clog in the toner conveyance path and result in poor toner conveyance.
To counteract this problem, the image forming apparatus employing the above-described known technique may include a toner discharge opening and a rotatably moving or rocking member. The toner discharge opening is disposed on a side wall forming the toner conveyance path to discharge toner to the toner conveyance path. The rocking member, such as a wire, is rotatably movable along a certain area of the inner wall of the toner conveyance path facing the toner discharge opening. By contacting the rocking member against toner particles that adhere to the inner wall facing the toner discharge opening, the toner particles can be removed from the inner wall. Thus, accumulation of toner particles on the inner wall of the toner conveyance path over time can be prevented, which can further prevent that narrowing of the toner conveyance path due to toner particle accumulations.
However, in the related-art image forming apparatus employing the above-described known technique, the rocking member cannot remove toner adhering to areas other than the above-described area of the inner wall of the toner conveyance path. Therefore, toner can accumulate with time onto the other areas of the inner wall of the toner conveyance path, which can cause the toner conveyance path to become narrower, and can result in poor toner conveyance.

Powder conveyance unit and image forming apparatus including same


A radiation therapy apparatus includes a compensator having a plurality of leaves to divide the radiation beam into rays each of which may be effectively and individually attenuated over a range of attenuations by controlling the duty cycle of the leaves position between the open and closed states. An apparatus for controlling the compensator accounts for scattering of radiation through the deconvolution of a terma map and calculates a sinogram for controlling the compensator at a variety of angles about a patient using iterated forward and back projections efficiently calculated in frequency space.

1. Field of the Invention
This invention relates generally to radiation therapy equipment for the treatment of tumors, or the like, and specifically to a compensator mechanism and associated radiation therapy planning software for regulating the dose of radiation within irregularly shaped zones within the patient.
2. Background Art
Medical equipment for radiation therapy treats tumorous tissue with high energy radiation. The dose and the placement of the dose must be accurately controlled to insure both that the tumor receives sufficient radiation to be destroyed, and that damage to the surrounding and adjacent non-tumorous tissue is minimized.
Internal-source radiation therapy places capsules of radioactive material inside the patient in proximity to the tumorous tissue. Dose and placement are accurately controlled by the physical positioning of the isotope. However, internal-source radiation therapy has the disadvantages of any surgically invasive procedure, including discomfort to the patient and risk of infection.
External-source radiation therapy uses a radiation source that is external to the patient, typically either a radioisotope, such as .sup.60 Co. or a high energy x-ray source, such as a linear accelerator. The external source produces a collimated beam directed into the patient to the tumor site. External-source radiation therapy avoids some of the problems of internal-source radiation therapy, but it undesirably and necessarily irradiates a significant volume of non-tumorous or healthy tissue in the path of the radiation beam along with the tumorous tissue.
The adverse effect of irradiating of healthy tissue may be reduced, while maintaining a given dose of radiation in the tumorous tissue, by projecting the external radiation beam into the patient at a variety of "gantry" angles with the beams converging on the tumor site. The particular volume elements of healthy tissue, along the path of the radiation beam, change, reducing the total dose to each such element of healthy tissue during the entire treatment.
The irradiation of healthy tissue also may be reduced by tightly collimating the radiation beam to the general cross section of the tumor taken perpendicular to the axis of the radiation beam. Numerous systems exist for producing such a circumferential collimation, some of which use multiple sliding shutters which, piecewise, may generate a radio-opaque mask of arbitrary outline.
As part of collimating the beam to the outline of the tumor, the offset angle of the radiation beam, with respect to a radius line between the radiation source and the center of rotation of the radiation source, may be adjusted to allow the treated area to be other than at the center of rotation. Simultaneously changing the offset angle and the width of the radiation beam as a function of gantry angle allows tumorous tissue having an irregular cross-section within a plane parallel to the radiation beam to be accurately targeted. The width and offset angle of the radiation beam may be controlled by the use of a multiple-leaf collimator.
Adjustment of the offset angle, center, and size of the radiation beam at various gantry angles allows considerable latitude in controlling the dose. Nevertheless, these approaches still impart a considerable amount of undesired dose to healthy tissue, especially where the tumor is concave or highly irregular.

Method and apparatus for radiation therapy


A resin composition includes                (A) a thermally-conductive organic additive including a liquid crystalline thermoplastic resin which has a mainly-chain structure, wherein a main chain of the liquid crystalline thermoplastic resin contains mainly a repeating unit represented by the general formula (1):-M-Sp-  (1)where M represents a mesogenic group and Sp represents a spacer,        (B) a thermosetting resin; and        (C) an inorganic filler.

In a case where a thermoplastic resin composition is used for various applications such as housings of a personal computer and a display device, an electronic device material, automotive exterior and interior parts, and the like, there sometimes occurs a problem that it is difficult to release generated heat because plastic is less thermally conductive than an inorganic substance such as a metal material. In order to solve such a problem, an attempt has been extensively made to obtain a highly thermally conductive resin composition by blending, with a thermoplastic resin, a highly thermally conductive inorganic compound in a large amount. In order to obtain a highly thermally conductive resin composition, it is necessary to blend, with a resin, a highly thermally conductive inorganic compound such as graphite, carbon fiber, alumina, or boron nitride generally in an amount of not less than 30 vol % and further in an amount of as many as not less than 50 vol %. However, when an inorganic compound such as graphite or carbon fiber is blended in a resin in a large amount, the resin will have a reduced electrical insulation property and thereby become electrically conductive. This causes a problem that only a limited portion of the resin can be used in an electronic device application. Further, when a ceramic filler such as alumina is blended in a resin in a large amount, the resin will cause abrasion on a mold due to a high hardness of the filler, in a case where the resin is used as a molding material. Further, since a high density of the filler will increase the density of an obtained composition, the resin makes it difficult to reduce the weight of an electronic device or the like. Another approach to use a filler which has a relatively low density and hardness, such as a boron nitride filler, has also been reported. However, even if such filler is used, it is inevitable that blending an inorganic compound with a thermoplastic resin significantly lowers molding processability of a resin composition, as long as the inorganic compound is added to the resin in a large amount. This is because an inorganic compound cannot be dissolved at a molding temperature of a resin.
From such a viewpoint, it has been strongly desired to develop a thermally-conductive organic additive which (i) has properties such as a low density, a low hardness, and an electrical insulation, and (ii) can be dissolved at a molding temperature of a resin.
Epoxy resins described in Patent Literatures 1 and 2, or bismaleimide resins described in Patent Literature 3, for example, have been reported as a thermosetting resin in which a resin per se has an excellent thermal conductivity. Unfortunately, these resins cannot improve molding processability of a resin composition since the resins have a thermosetting property and are not dissolved at the molding temperatures of the resins.
In contrast, there have been some examples of researches on a thermoplastic resin as to a special molding process such as extension or magnetic field orientation during an injection molding process so as to give the thermoplastic resin a high thermal conductivity in a specified direction. However, these techniques are not applicable to a thermally-conductive organic additive.

Thermally-conductive organic additive, resin composition, and cured product


A method of monitoring state of health for an energy generation system includes receiving a measurement of a parameter of an electrical component in the PV energy generation system at an instance in time, referencing a look-up table containing several values of the parameter representing an expected degradation trend across a progression of time for the electrical component, comparing the measurement to an expected value of the expected degradation trend for a period of time corresponding to the instance in time, and initiating a preventative measure based upon the comparison between the measurement and the expected value of the expected degradation trend.

In recent years, climate change concerns, reduction in costs, governmental initiatives, and other factors have driven a rapid rise in the adoption of renewable energy generation systems (i.e., systems that generate energy using renewable resources such as solar, wind, fuel cells, geothermal etc.) at residential and non-residential sites. Solar energy generation systems, in particular, have been very popular due to numerous advantages over other renewable and non-renewable energy sources.
Solar energy generation systems include photovoltaic (PV) modules that generate power from the sun, and can provide the generated power to a utility grid or to one or more on-site loads. Some solar energy generation systems can store energy from the PV and/or utility grid in a battery for future use, and can receive power from the utility grid and re-route power to the one or more loads without having to use power generated from the sun or from energy stored in the battery.
As with any electrical system, continuous use causes solar energy generation systems to degrade over time. Once systems degrade to a certain point, the system can fail to operate, reducing the solar value proposition and necessitating complex troubleshooting and costly repairs. Troubleshooting solar energy generation systems can be substantially onerous given the large number of electrical components utilized in a typical energy generation system. Furthermore, initiating repairs of an energy generation system once it has already failed may result in large system downtime until it is repaired. Thus, improvements to the reliability of solar energy generation systems are desired.

State of health mechanisms for energy generation systems


Provided is an image processing method, the method including heating a thermoreversible recording medium with laser beams to erase an image which has been recorded on the thermoreversible recording medium, the thermoreversible recording medium reversibly changing between a colored state and a decolored state depending on a heating temperature and a cooling time; heating the thermoreversible recording medium, on which the image has been erased, with the laser beams to record a subsequent image on the thermoreversible recording medium; and measuring at least one of a surface temperature of the thermoreversible recording medium and a recording environmental temperature after a completion of erasing the image but before a beginning of recording the subsequent image to obtain a measured temperature value and controlling a time interval between the completion of erasing the image and the beginning of recording the subsequent image depending on the measured temperature value.

Field of the Invention
The present invention relates to image processing methods, image processing apparatuses, and conveyor line systems using the image processing apparatuses.
Description of the Related Art
Recently, an image processing apparatus using a thermoreversible recording medium has been incorporated into and utilized in a conveyor line system which needs to manage a conveying container (e.g., returnable container employed in a physical distribution system). The thermoreversible recording medium is attached on the conveying container as a label and is rewritable with laser beams emitted from the image processing apparatus in a non-contact manner. This eliminates a need for attaching and peeling off a label, which makes it possible to efficiently operate the conveyor line system.
The thermoreversible recording medium contains, for example, a leuco dye and a reversible color developer. When the thermoreversible recording medium is heated to equal to or higher than a coloring temperature range in which the leuco dye and the reversible color developer melt and then rapidly cooled, the thermoreversible recording medium turns into a colored state (visible state). Meanwhile, when the thermoreversible recording medium is heated to a decoloring temperature range, which is lower than the coloring temperature range, held for a predetermined period of time, and then cooled, the thermoreversible recording medium turns into a decolored state (invisible state). However, even though the thermoreversible recording medium is heated to equal to or higher than the coloring temperature range in order to develop a color, if thermoreversible recording medium is then slowly cooled, the thermoreversible recording medium turns into the decolored state.
The thermoreversible recording medium having such property as described above is problematic in that, under a high temperature environment, the thermoreversible recording medium is decreased in coloring density since the thermoreversible recording medium which has been heated is difficult to be rapidly cooled. On the other hand, under a low temperature environment, there also is a problem that the thermoreversible recording medium is decreased in the coloring density since the thermoreversible recording medium is difficult to be held within the decoloring temperature range after the thermoreversible recording medium is heated.
In order to solve the above problems, there has been proposed a method for controlling laser beam power depending on a surface temperature of the thermoreversible recording medium (see, Japanese Unexamined Patent Application Publication No. 2008-194905).

Image processing method, image processing apparatus, and conveyor line system using image processing apparatus


An electromechanical power steering system having an electric servo motor having a motor shaft. The electric servo motor drives a shaft which meshes with a helical wheel. The shaft is rotatably supported in a gear mechanism housing. The motor shaft is coupled to the shaft in a rotationally secure manner by a coupling which compensates for an axial offset. The shaft at the end thereof close to the motor is supported in a bearing in the gear mechanism housing so as to be able to be rotated about a rotation axis and is pivotably supported about a pivot axis which is perpendicular to the rotation axis in such a manner that the pivot axis is arranged in the region of the coupling.

In electromechanical power steering systems, there is produced by means of an electric motor a torque which is transmitted to a gear mechanism and which is superimposed at that location on the steering torque provided by the driver.
A generic electromechanical power steering system comprises an electric power steering system which drives a worm shaft which meshes with a worm wheel which is arranged on a steering shaft, wherein the worm wheel is operationally connected to an input shaft of a steering gear mechanism and wherein the worm shaft and the steering shaft are rotatably supported in a common gear mechanism housing.
DE 10 2008 001 878 A1 and DE 10 2014 105 921 A1 disclose a pivot bearing for a worm gear mechanism, wherein the worm is supported by means of a gimbal-mounted bearing ring. The bearing ring comprises in this instance a pivot axis, which extends perpendicularly to the rotation axis and in the direction of the worm wheel. This embodiment has been found to be disadvantageous since the coupling is more heavily loaded, whereby the coupling over time becomes more rapidly worn and an increased toothed flank play occurs with corresponding vibration noises.
Thus a need exists for an electromechanical power steering system with a worm gear mechanism in which the coupling between the engine shaft and worm shaft is less heavily loaded.

Electromechanical power steering system having a pivotable bearing for a helical gearing


One embodiment of the present invention provides a system for allocating storage space for objects within a persistent object system. The persistent object system includes an object heap that is organized into a young generation region and an old generation region. The system uses the young generation region for newly created objects and uses the old generation region for objects that have not been removed by several garbage collection cycles. The system allocates storage space for new (transient) objects in the young generation region of the object heap. Periodically, the system copies the transient objects from the object heap to a stable store to form a checkpoint of the system state. Transient objects become persistent objects when they are copied to the stable store. Persistent objects are removed from the object heap when the system is stopped and when room is needed in the object heap for additional objects. When a persistent object that has been removed is referenced during execution of a computer program, the system faults the persistent object directly into the old generation region of the object heap from the stable store.

1. Field of the Invention
The present invention relates to allocating storage space for objects within a persistent object system. More specifically, the present invention relates to allocating storage space for persistent objects within the heap of a persistent object system that uses a generational garbage collector.
2. Related Art
Many modern computing devices, for example web servers, execute computer programs that are designed to run for long periods of time. It is advantageous for these computing devices to have a persistent object system that allows faster recovery when the computer program is stopped and restarted. A computer program can be stopped and restarted for a number of reasons. For example, the computing device may need maintenance, the power may fail, or a program executing on the computing device may fail.
A persistent object system provides the illusion of a very large object heap that is automatically backed by stable storage. During operation of a persistent object system, objects are automatically saved to stable storage, typically on a disk, and fetched from stable storage into virtual memory on demand.
Persistent object systems automatically perform atomic writes to stable storage in order to ensure that a program""s data will survive intact even if the program crashes. Hence, persistent programs (programs using a persistent object system) do not have to reinitialize the state of their objects when they restart. This reduces application startup time and eliminates the need for code to recreate and reinitialize objects.
To make persistent programs as fast as possible, object faulting must be efficient. This means that object heap allocation must be efficient. This is especially true for persistent programs as these programs often fault-in millions of objects. During object faulting space is allocated for an object in the program""s garbage collected object heap, and the persistent object is copied into the allocated space from the stable store.
Many high-performance garbage-collected object heap implementations are generational. They take advantage of the fact that most objects have a short lifetime and segregate objects into two or more regions of the object heap called generations. In a two generation object heap implementation, these can be termed a young generation region and an old generation region. New objects are allocated to the young generation region, which is garbage collected frequently to reclaim the storage of short-lived objects. Long-lived objects that survive several young generation garbage collections are promoted (moved) to the old generation region.
Faulting persistent objects into the young generation can make garbage collection, especially young generation garbage collection, much more time-consuming than garbage collection of non-persistent systems. Objects faulted-in by a persistent object system tend to have longer lifetimes than newly allocated transient (non-persistent) objects. Hence, when a faulted-in object is allocated in the young generation region, it usually ends up being promoted to the old generation region after several young generation region garbage collections creating needless work for the young generation garbage collector.
References from the old generation region to the young generation region are normally rare but are common in persistent object systems where persistent objects are faulted-in to the young generation region. The young region garbage collectors must do substantial work for the persistent objects faulted-in to the young generation region because object heap implementations store references from the old generation region to the young generation region in data structures that are designed to save space rather than for fast processing.
If the rate at which persistent objects are faulted-in is high, the young generation region is mostly filled with long-lived persistent objects. This causes the rate of the young region garbage collections to increase. Also, each of the young region garbage collections will reclaim only a small number of objects. Furthermore, each young region garbage collection will typically be much more expensive because of the cost of processing a large number of references from the old generation region to the young generation region as explained above.
Hence, faulting persistent objects to the young generation region of the object heap is inefficient.
What is needed is a persistent object system that eliminates the above-described disadvantages of faulting a persistent object into a young generation region of an object heap.
One embodiment of the present invention provides a system for allocating storage space for objects within a persistent object system. The persistent object system includes an object heap that is organized into a young generation region and an old generation region. The system uses the young generation region to store newly created objects and uses the old generation region to store objects that have not been removed by several garbage collection cycles. The system allocates storage space for new (transient) objects in the young generation region of the object heap. Periodically, the system copies the transient objects from the object heap to a stable store to form a checkpoint of the system state. Transient objects become persistent objects when they are copied to the stable store. Persistent objects are removed from the object heap when the system is stopped and when room is needed in the object heap for additional objects. When a persistent object that has been removed from memory is referenced during execution of a computer program, the system faults the persistent object directly into the old generation region of the object heap from the stable store.
In one embodiment of the present invention, the object heap is located in a virtual memory of the persistent object system.
In one embodiment of the present invention, the object heap can include regions for generations other than the young generation region and the old generation region.
In one embodiment of the present invention, transient objects are newly created objects.
In one embodiment of the present invention, the generational garbage collector reclaims unreferenced objects. In doing so, the generational garbage collector first deletes objects that are no longer referenced from the object heap. Next, the generational garbage collector reallocates storage space formerly used by the deleted objects within the object heap. Finally, the generational garbage collector promotes transient objects from the young generation region of the object heap to the old generation region of the object heap if the transient object is not deleted by the generational garbage collector after a user configurable number of garbage collections.
In one embodiment of the present invention, the system copies transient objects to the stable store in order to generate a checkpoint of a state of the computer program.
In one embodiment of the present invention, the persistent object is removed from the object heap because the persistent object system required more space within the object heap, the persistent object system was shut-down or stopped because of a hardware or software error; or the persistent object system was subject to a system crash or power failure.
In one embodiment of the present invention, the system faults persistent objects directly into the old generation region of the object heap by allocating space in the old generation region of the object heap, and then copying the persistent object from the stable store to the old generation region of the object heap.

Efficient object faulting with generational garbage collection


A test detect and shut off circuit for a BiCMOS integrated circuit is presented. The test detector/shutoff detects the presence of a predetermined test condition in the BiCMOS integrated circuit (IC), and upon detection of the predetermined condition isolates (i.e., switches off) the bipolar circuit portion from the CMOS logic portion of the BiCMOS IC. In this way, bias current in the bipolar transistor circuit is eliminated, thereby facilitating IDD testing of the BiCMOS logic. The detector/shutoff is particularly designed for BiCMOS implementations wherein a single voltage rail supplies voltage V.sub.DD to the logic and bipolar circuit portions of the IC. Corresponding test detect and circuit isolation methods are also presented.

In the semiconductor fabrication industry, it is necessary to test an integrated circuit during fabrication by pre-testing and after fabrication by final testing, in order to obtain better detection of any defects occurring therein. However, as the degree of integration and complexity of integrated circuits continues to increase, the number of external connections available has not kept pace so that it has become more and more difficult to test complex integrated circuits.
Complicating testing of BiCMOS ICs is the need to isolate BiCMOS logic from the bipolar circuits during certain testing processes. Also, multiple bipolar circuit pathways may be coupled between supply voltage V.sub.DD and an intermediate supply voltage V.sub.TT, wherein V.sub.DD >V.sub.TT >GND. (Typically, today's BiCMOS devices operate with a 3.6 volts V.sub.DD supply voltage and a 1.5 volts V.sub.TT supply voltage.) Further, because of a limitation on the number of connections available, a BiCMOS integrated circuit may have CMOS logic coupled in parallel with certain bipolar circuits between an operating circuit voltage V.sub.DD and a ground potential. These bipolar circuits (such as ECL I/O circuits) commonly have a high standby current.
One well known circuit test in the semiconductor fabrication art is the "IDD test" or "IDD current test". This test attempts to measure the quiescent current of a chip between supply voltage V.sub.DD and ground potential GND. The test is conventionally used to screen early AC,DC and reliability defects in CMOS and BiCMOS logic parts. Industry standards are well established for IDD current test measurements and various articles are available in the open literature which describe the testing process. Essentially the test seeks to determine the extent of leakage current through the BiCMOS logic. The amount of leakage current is recognized as an indication of the quality of a chip. The lower the magnitude of the leakage current, the better the chip quality.
In the BiCMOS environment, the IDD test is traditionally conducted on a per cycle/per pattern basis on internal logic circuits with separate power busing for the bipolar circuits, i.e., separate voltage rails are employed to separately supply voltage V.sub.DD to the logic and to the bipolar circuits. Because separate power supply rails are used, leakage current through the logic circuits is obviously isolated from standby current through the bipolar circuits, which is normally at least an order of magnitude higher than the leakage current. In this configuration, isolation is ensured by removing the supply voltage V.sub.DD at the voltage rail supplying the bipolar circuits. Unfortunately, in view of ever increasing integrated circuit complexity, many BiCMOS circuit designs must utilize a common pin for supplying voltage V.sub.DD to the bipolar circuit pathways and to the internal logic.
Again, bipolar circuit bias current is typically much higher than leakage current in the BiCMOS logic portion of a semiconductor chip. (For example, in BiCMOS logic designs, IDD current is typically on the order of microamps while bipolar circuit bias current is in the range of milliamps.) In the common power supply rail embodiment, the high currents drawn by the I/O related bipolar circuits make it difficult during IDD testing to detect the low level quiescent IDD currents of the BiCMOS logic coupled in parallel therewith. Therefore, a recognized need exists in such circuits to isolate the bipolar circuit pathways from the parallel coupled BiCMOS logic pathways for accurate testing thereof.
One prior attempt to address this problem is described in Japanese Patent No. 63-186462 entitled "Semiconductor Integrated Circuit". In this patent, a BiCMOS integrated circuit is presented which allows measurement of only the power source current of a CMOS circuit by providing a switching circuit to cut off the power source current of the bipolar circuit portion at the time of the test processing. A MOSFET switching circuit is described which is responsive to an applied signal at a dedicated test terminal. By applying an appropriate voltage at the test terminal, switching of the bipolar circuit can be obtained, i.e., power source current can be made to flow only in the CMOS circuit portion of the BiCMOS IC. The disadvantage to the approach, however, remains the need to dedicate an additional terminal (i.e., the test terminal) to attain the desired isolation of the CMOS logic.
Therefore, a need exists in the industry for a means for shutting off IDD current through bipolar circuits coupled in parallel with BiCMOS logic between supply voltage V.sub.DD and ground potential GND. Such selective isolation would allow meaningful IDD testing in a BiCMOS environment without the addition of an extra terminal to accomplish the test.

Test detector/shutoff and method for BiCMOS integrated circuit

International Business Machines Corporation


A method and system for correcting the effect of intensity fluctuations of the transmitted light in an absorption spectroscopy system used for the detection or measurement of chemical species in a medium, whereby one or more modulation bursts are imposed onto a light beam that passes through the medium. This burst signal may be obtained by modulating the bias current of a tunable diode laser, and the modulation burst signal may be optimally at the second harmonic of the modulation frequency of a wavelength modulated beam to allow usage of the same signal path processing used for the spectroscopic detection of the measurand for a second harmonic detection system. The burst signal can be controlled using a smooth window function to minimise the effects of non-linear perturbations that are inherent in tunable diode laser wavelength modulation spectroscopy systems, of optical interference fringes (etalons) and of the residual light absorption by background chemical species or the measurand at the wavelength coinciding with the modulation burst.

Tunable laser wavelength modulation spectroscopy is finding widespread use in various applications. One such application is the quantification of the amount of chemical species (the measurand) in a substance and in particular in an artificial or natural process such as an industrial, medical or physiological process gas analysis where traditional techniques are either unsuitable or poor.
A typical system consists of a tunable laser source such as a tunable diode laser (TDL) that emits a beam of light that is focussed on a detector. The substance that is to be analysed is positioned between the tunable laser source and the detector, so that the light incident on the detector has been modified by its passage through the substance. The modifications to the light enable various parameters of the measurand to be determined by a signal processing system that is coupled to the detector. In some cases the substance to be analysed is a gas produced by an industrial process, and the measurand may be one or more chemical species that are present in this process gas. Examples of measurand species include but are not limited to gaseous water, O2, CO and CO2 and hydrocarbons such as methane. The presence and/or amount fraction (concentration) of one or more of these measurand species may be determined using one or more TDLs.
In operation of the laser gas analyser system, the wavelength of the beam emitted by the TDL is scanned over one or more absorption lines of the measurand. At certain specific wavelengths within the range of wavelengths scanned, light is absorbed by the measurand and these spectral absorption lines can be detected by measuring the light transmitted through the substance to be analysed. This allows the necessary spectroscopic information to be acquired to determine not only the amount fraction of the measurand, but also the influence of pressure, temperature or background mixture composition. In some cases it is possible to use a single laser source to measure a plurality of measurands. In these cases, the output wavelength of the laser source is swept across a wavelength range that includes at least one discernable absorption line for each of the plurality of measurands.
In a well-designed system, wavelength modulation techniques offer very high sensitivity and enhanced spectral resolution. In particular, second harmonic wavelength modulation spectroscopy is well suited to gas analysis due to its ability to cope with a wide variety of spectroscopic situations found in industrial processes that includes congested absorption spectra, sensitive trace level measurements and obscured optical transmission.
The detector response is proportional to the intensity of light transmitted through the substance under test, which is dependent on the intensity of light transmitted through the substance under test as well as the amount fraction of measurand at the absorbing wavelengths. Therefore fluctuations of the light intensity caused by either the laser source or transmission through the analysed substance will cause uncertainty in the measurement of the amount fraction of measurand.
This is shown by the following relationships, where equation [1] represents the Beer-Lambert law of optical absorption, wherein u is the molecular density per unit length of the measurand, I is the detected amount of light, I0 is the incident amount of light (equal to unabsorbed amount when the molecular density is zero), v is the frequency of light and k is the absorption coefficient.
                              log                                [                                          I                                                  (                  v                  )                                                                              I                  0                                                                  (                  v                  )                                                      ]                          =                  -                      uk                                      (              v              )                                                          [        1        ]
The change in the amount of light detected at any particular frequency (∂I(v) is related to the molecular density change (∂u) as given by equation [2], which also shows the uncertainty term due to variation of the incident amount of light (∂I0)
                              ∂          u                =                                                            ∂                                                      I                    0                                                                          (                    v                    )                                                                                I                  0                                                                  (                  v                  )                                                      -                                          ∂                                  I                                                        (                    v                    )                                                                              I                                                  (                  v                  )                                                                          k                                      (              v              )                                                          [        2        ]
Variations in incident light intensity at the detector may be caused by a number of factors other than the concentration of the measurand. For example, variations can be caused by intrinsic fluctuations in the laser output, changes in ambient light intensity levels and/or obscuration in the process sample stream, which may be caused by any combination of dust, tar, corrosion or optical beam misalignment. Obscuration and changing of the intensity of ambient light are to be expected in a furnace. If the variation in incident light is not corrected, this will result in a measurement uncertainty in the processed measurand concentration. Some prior art techniques have been developed to deal with these sources of error. However, the techniques are not well suited for use with TDLs.
One known technique to reduce errors from ambient light is to use interference filters to block a large amount of the broadband light from an ambient light source. However, it is unavoidable that a small but significant amount of ambient light will get through the filter pass band used for the measurement. A prior art technique for negating the error introduced by this residual ambient light is to periodically turn off the laser. This allows the level of residual ambient light to be measured and corrected for. Specifically, the difference in detector signal between the on and off states indicates the amount of incident laser light, thus allowing the residual ambient light to be determined and compensated for. To make use of this technique, however, the laser must be turned off frequently, since ambient light levels will typically vary unpredictably over relatively short timescales, and this technique is not well suited for use with a tunable diode laser. The problem is that repeatedly turning the diode laser on and off causes significant ohmic heating within the diode laser, which is problematic because ohmic heating also affects the wavelength of the output beam of the laser. This dynamic response is referred to as ohmic heating perturbation. Consequently, when this technique is used with TDLs, the laser wavelength scan suffers from large linearity errors, which distorts the measured absorption line shape.
One possible technique to address the error caused by intrinsic fluctuations in the laser output power is to monitor the laser output power while measurements are being made. The laser output power can be monitored at a 'neutral' wavelength that is not absorbed by the measurand or other interfering chemical species, and this signal can be compared with a reference value to allow any variations to be corrected for. This results in the measured signal being standardised to a reference value for the amount of incident light. This technique may not be practical in a congested absorption spectrum and could lead to errors.
An alternative method of compensating for variations in the incident light caused by fluctuations in the laser output power is to simultaneously perform second harmonic wavelength modulation spectroscopy and first harmonic modulation spectroscopy. First and second harmonic modulation spectroscopy is known to those skilled in the art and will not be described further here. By taking the ratio of the second harmonic signal to the first harmonic signal, a quantity is obtained that is theoretically independent of the incident light variation for the optically thin regime i.e. weak absorption. However, the inclusion of the first harmonic signal negates the enhanced spectral resolution advantage of using the second harmonic signal alone. Therefore, any interfering background absorption will cause measurement uncertainty of the ratio. This means that this technique is not well suited to situations where many different species are present alongside the measurand, particularly if these species have absorption lines close to or even overlapping those of the measurand. This is often the case in a process gas that is output from an industrial process, for example. In addition, the implementation is more difficult than a standard wavelength modulation spectroscopy system as two separate signal processing channels are required for simultaneous first and second harmonic detection.
A further complication with this technique when used with TDLs is that the residual amplitude modulation (RAM), which is always present when modulating laser diodes using the bias current, adds additional measurement uncertainty to the above ratio. Although the RAM uncertainty can be corrected for by characterising the diode laser intensity modulation behaviour, these modulation characteristics change with the diode laser temperature and bias current settings. The diode laser is normally temperature controlled, which is necessary to achieve frequency stability, and, in an ideal situation, the diode laser temperature is unconditionally stable and hence the modulation characteristics are also stable. However, for a rugged industrial analyser that must cope with wide ambient temperature swings, even the best diode laser temperature control will experience some residual temperature change due to finite thermal control gain. In some cases, the residual temperature change may be significant enough to require retuning of the diode laser frequency onto the measurement absorption line.
Furthermore, the amount of RAM is dependent on the frequency modulation sensitivity of the diode laser as the bias current modulation amplitude is adjusted to achieve sufficient frequency modulation range in order to obtain adequate signal from the wavelength modulation spectroscopy. However, the frequency modulation sensitivity varies among different types of diode lasers. For example, distributed feedback (DFB) structure laser diodes have comparatively low frequency modulation sensitivity, typically less than 0.1 cm−1 per milliamp bias current resulting in large RAM, whereas, vertical cavity semiconductor emitting lasers (VCSEL) tend to have much larger frequency modulation sensitivity, typically greater than 5 cm−1 per milliamp bias current resulting in much lower RAM. There remains a need for an absorption spectroscopy gas analyser system that can produce highly accurate measurements despite fluctuations in the intensity of the transmitted light. There is also a need for such an analyser system that is able to produce highly accurate measurements in a harsh environment as may typically be found in many industrial processes, such as in a furnace or furnace exhaust pipe.

Method and system for correcting incident light fluctuations in absorption spectroscopy


An apparatus for sampling or feeding a flowable material through a wall of a vessel or conduit includes a body having a collection chamber formed therein. A passage has an opening operatively connected to the collection chamber. An orifice is formed in the body and is in communication with the collection chamber. The orifice is located generally adjacent the opening of the passage. A sealing device is mounted to the body to seal and unseal said orifice. Furthermore, at least a portion of the opening of the passage is located flush with or on a process side of the wall of the vessel or conduit when the apparatus is mounted to the wall of the vessel or conduit.

1. Field of the Invention
The present invention relates to the field of sampling, feeding or inoculating of material from or to a vessel or conduit.
2. Description of Related Art
Quality products require precise control of many phases of a production process. It is also true that it is necessary to maintain the integrity of the process and to protect the surroundings from the process. While many advances have been made in the development of sensors for measuring the condition of a specific process on-line which will aid in maintaining this process integrity, many of the characteristics of processes still need to be measured off-line through the physical and/or chemical analysis of an actual sample of the process. The removal of the sample from the process has to be conducted in a way that will preserve the integrity of the process, the surrounding environment as well as the integrity and character of the sample itself.
In a related but different procedure, many processes require inoculation of seed organisms or catalysts into a process to initiate the conversion of a set of substrate materials into other process intermediates or a final product or set of products. Sometimes this seed material is a live organism, a component of a live organism or another form of catalyst. In any case, these materials frequently need to be added to a process in a way that maintains the integrity of the process, the materials being added and their source, the integrity of the surrounding environment, or, perhaps, all of these.
There are examples of devices in the prior art that provide a means to deliver or withdraw materials from a process while maintaining the integrity of the process, the sample or the feed material or the surrounding environment but these devices are restricted in their effectiveness, particularly in their abilities to maintain the integrity or character of either the sampled material or material being added to the process because these devices have designs that are optimized for use in certain physical orientations. When used in orientations other than those they are designed for, these devices frequently suffer from the presence of crevices, particularly between component joints exposed to the process, and from design features that inhibit free flow and drainage of flowable materials through the device, resulting in pooling within the device. Both the crevices and pooling phenomena result in material carryover from one sampling, feeding or inoculation episode to the next, causing the deterioration in quality of any subsequent material introduced through sampling, feeding or inoculating into these devices.
It is also the case that some of these devices are not designed to be reused or, if they are designed for reuse, must be removed from the process and cleaned and sometimes resterilized before being able to be used again with the process.
There is a need for an apparatus that can be fitted, either permanently or removably, into a process which will allow materials to be fed, inoculated to or sampled from a process through a device principally designed to provide access to the process from above but which may provide reasonably good access to a process when installed at angles from vertical to horizontal. It is also desirable that an embodiment of this device provide a means by which it can be washed and sterilized in place and a means by which the thermal and electrical conditions inside the device be generally insulated from those of the process into which it is inserted. It is further desirable that the device, when placed in installations from vertical to horizontal relative to the process, be able to accumulate flowable materials occurring in the device in an area where they may be expelled or washed out by the introduction of other flowable materials under pressure coming either from the process or a second source through another access into the device.
In the existing art, there are examples of devices that provide a means for adding materials to the process but do not provide a means for washing and resterilizing in place and for effectively draining sampled material or cleansing, rinsing or sterilizing solutions from within the device.
Referring to FIG. 15 of the present invention, a description of a Background Art device will be described. The Background Art device consists, in essence, of a pipe section 300 mounted through the wall of a vessel or conduit 301. One end 303 of the pipe section 300 opens into the process contained in the vessel or conduit 301 and the other end 305 opens to a supply located outside the vessel or conduit 301. Flow into or out of the vessel or conduit 301 is controlled by a flow control valve 307 mounted outside the vessel or conduit 301 at a position intermediate between the supply and the outer wall of the vessel or conduit 301.
The above design approach is universally used for making additions and, in many cases, withdrawals from processes because it is simple, easily maintained, cost effective to purchase and operate and lends itself easily to a wide range of desirable processing upgrades, redundancies and controls. For sanitary or aseptic processing, the most important of these may be the ease with which seal redundancy (in the form of redundant in-line flow control valves) and secondary valving (for in-place cleaning and sterilizing) can be designed and added to the basic in-line flow control valve 307.
For example, referring to FIG. 15 again, a secondary flow control valve 309 can easily be added to obtain a redundant seal. The portion 314 of the pipe section 300 upstream of the secondary flow control valve 309 can easily be cleaned by a supply of material through the opening 305 and out of the drain passage 315 when the secondary flow control valve 309 is closed and the valve 317 is open. In addition, the portion 316 of the pipe section 300 between the secondary flow control valve 309 and the seal of the primary flow control valve 307 can be easily cleaned by closing the secondary flow control valve 309 and opening the valve 319 in the inlet passage 321 and the valve 325 in the drain passage 323. Therefore, flow through the inlet passage 321, the portion 316 and out of the drain passage 323.
Today, the average cost of valves is decreasing, while the average cost of failed batches of process is increasing. Therefore, it is not surprising to one familiar with industrial production today to see the great proliferation and sophistication of primary and secondary redundant valving systems being designed and installed in an effort to ensure better monitoring, control and maintenance of the environment around the primary flow control seal with the process and a secondary redundant seal, when present, as well as the environment between the two valve seals in an effort to protect and ensure the quality and integrity of the process.
In spite of all of the design effort and expense going into development and installation of evermore elaborate conventional external in-line valving systems to control flow into vessels (and contain the process within), no comprehensive solution has yet been offered to rid production systems of the deadspace 311 that occurs between the seal of the primary flow control valve 307 and the opening 303 of the pipe section 300. Without the availability of such a device, there is also no device available that allows, nor has a device or system been made available that would permit periodic recleaning and resterilizing of such a deadspace 311 within the production environment periodically during production runs. As a consequence, any type of supply port 313 into a vessel or conduit 301, including gas sparging devices, may experience stagnation, material build-up and line blockages, particularly during extended production runs. Since blockages become more severe with time, the inability to intermitently reclean and/or resterilized to remove blockages and restore full flow capacity can significantly diminish the operator's ability to control and optimize the process.
Eliminating the risk to the process posed by an uncleanable deadspace 311 currently existing in supply port systems as well as many sample capture or harvesting valve systems would be an important step in assuring the quality and productivity of processes. Ideally the solution should be done without losing the advantages offered by current supply port system designs, including the ability to clean and steam sterilize the upstream portion 316 of the seal of the primary flow control valve 307 with the process while it remains on-going, the ability to design in flow control valve redundancy and the ability to monitor, control and maintain the environment between primary and secondary (redundant) flow control valve seals. It is also of value for the solutioin to be usable in a variety of process applications that are heat sensitive without damaging those processes.