A fiber optic gyroscope including an optical circulator in the path of said first and second beams for providing polarized first and second beams of identical polarization. A phase modulator couples the first and second beams to the first and second end respectively of the fiber loop, and couples for receiving the return first and second beams from the second and first ends respectively of the fiber loop. First and second photodiodes are coupled to the optical circulator for receiving the optical signal from the first and second return beams.

1. Field of the Invention
The invention relates to fiber optic gyroscopes (FOGs) and in particular to integration techniques that utilize planar array technology to implement a FOG transceiver subassembly in a small, compact form factor.
2. Description of the Related Art
A FOG is a device that uses the propagation of light beams in an optical fiber coil to detect mechanical rotation of the fiber coil. The sensor is a coil of as much as 5 km of optical fiber. The typical implementation provides that two light beams be launched into the fiber in opposite directions. Due to an optical phenomena known as the Sagnac effect, the beam traveling against the rotation experiences a slightly shorter path than the other beam resulting in a relative phase shift. The amount of the phase shift of the original two beams can be measured by determining how the beams interfere with each other when they are combined. The intensity of the combined beam then depends on the rotation rate of the fiber coil about its axis.
A FOG provides extremely precise rotational rate information, in view of its lack of cross-axis sensitivity to vibration, acceleration, and shock. Unlike the classic spinning-mass gyroscope, the FOG has virtually no moving parts and no inertial resistance to movement. The FOG also provides a higher resolution than a ring laser gyroscope and is utilized in internal navigation systems requiring a high degree of accuracy.
There are two types of FOG systems, closed loop and open loop. In a closed loop system, a feedback path is defined so as to maintain the phase difference between the light beams constant after the beams exit the ends of the fiber coil. The amount of feedback needed to maintain the fixed phase relation is therefore indicative of the rate of rotation of the coil about its axis.
Open loop FOG systems calculate the rotation rate by way of amplitude measurements taken along an interference curve which results when the two exiting light beams are recombined.
Prior to the present invention there has not been a small, low cost fiber optic gyroscope in a highly integrated form factor.


Spray arm for a coating device and a method of supplying a coating material to a spray arm. The spray arm including at least one nozzle pipe having an open end, a closed end, and at least one nozzle positioned between the open end and the closed end, and at least one delivery pipe having a supply end and a delivery end. The delivery end may be positioned adjacent the closed end of the at least one nozzle pipe, the open end of the at least one nozzle pipe may be couplable to a coating material supply, and the supply end of the at least one delivery pipe may be couplable to the coating material supply. The method includes supplying coating material to the at least one nozzle in a first direction substantially along a longitudinal axis of the at least one nozzle pipe, and supplying coating material to the at least one nozzle in a second direction, the second direction being substantially opposite the first direction.

1. Field of the Invention
It is the object of the present invention to provide a spray arm for a coating device as, for example, is known from DE 43 23 535 A1 of the same applicant.
2. Discussion of Background Information
The object of invention of said application was to supply the nozzles, which are arranged on a nozzle pipe of the spray arm, over the length of the spray arm with a liquid which is as constant as possible, supplying said liquid compound to each nozzle.
If on one side of a nozzle pipe, on which is arranged a series of ejection nozzles, a high-viscosity compound is introduced, this will result in a proportional drop in pressure over the length of the nozzle pipe resulting in the first nozzle located in the direction, in which the compound is introduced, discharging comparatively more coating compound than the nozzle located at the end of the nozzle pipe.
This proportional drop pressure is disadvantageous and must be avoided.

Spray arm for coating device and method of spraying a coating through the spray arm


Upward variations of a molten metal level in a container for melting metallic material shall be carried out by detecting variations of a liquid level inside a detector connected to a gas-pipeline, wherein a rise in the pipeline pressure causes the liquid level to move down. Communication is established by means of a gas-pipeline 13 for inert gas between that portion of a container for melting metallic material which is above a molten metal surface 15a and that portion of a detector 16 comprising a transparent tubular container 18 which is above a liquid surface 17a. Variations of the liquid level 17a inside the detector 16 due to a rise in the pressure inside the above-mentioned gas-pipeline 13 are detected as upward variations of the level of the molten metal surface.

1. Field of the Invention
The present invention relates to a method and apparatus for detecting a molten metal level inside a container for melting metallic material in a case where a nonferrous metal having a low melting point, such as zinc, magnesium, or an alloy thereof, is melted to be subjected to injection molding in a liquid phase state.
2. Detailed Description of the Prior Art
It is necessary to detect molten metal levels for reasons including: the need to prevent the overflowing of molten metal stored inside a container for melting metallic material, such as a melting furnace; or the need to control operations wherein unmolten metallic material is fed into containers for melting metallic material.
Known means for detecting molten metal levels are: an indirect method using a photoelectric sensor or the like, wherein light is shed on the surface of molten metal, and the resulting reflected light is sensed to detect the molten metal level; and a direct method using a conduction sensor or the like, wherein an electrode is directly inserted in molten metal, and it is determined whether or not continuity exists between the electrode and the molten metal, thereby detecting the molten metal level.
However, in the case of either of the above-mentioned two methods, it is necessary to install a sensor in a high-temperature portion inside a container for melting metallic material, and therefore, any usable sensor is subject to restriction. Furthermore, if the container for melting metallic material is so constructed as to have an intricately complicated interior, or if the container for melting metallic material is so arranged as to have a very small interior, then it is difficult to detect the molten metal level by means of either a conventional photoelectric sensor or a conventional conduction sensor.
In particular, since the detection of a molten metal level by means of a photoelectric sensor is carried. out by sensing reflected light, this method cannot be used in the case of an arrangement wherein the interior of a container for melting metallic material is bent, thus preventing the surface of molten metal from being viewed from the position where the photoelectric sensor is installed. Even if the above-mentioned interior is so arranged to permit the photoelectric sensor to be used, the construction of the portion where the photoelectric sensor is installed becomes so complicated as to present a problem in that the cost of the sensor itself becomes high.
Moreover, in the case of the direct detection of a molten metal level by means of a conduction sensor, molten metal is prone to remain attached to the electrode portion located at the tip of the conduction sensor. The molten metal attached as above presents no particular problem in the event that the interior of a container for melting metallic material is large enough to permit a sufficient distance to be secured between the conduction sensor and the wall surface of the container. However, if the interior of a container for melting metallic material is small, then the distance between the conduction sensor and the wall surface of the container is inevitably short, and therefore, the electrode portion of the sensor and the wall of the container are prone to contact each other on account of the molten metal attached to the electrode portion, resulting in continuity being present at all times. Consequently, the conductivity sensor loses its function, thus presenting problems such as failure to carry out detection.
Furthermore, in addition to the above-mentioned methods for detection, there exists a method wherein inert gas is adopted as a detecting medium; the through-flow and the absolute value of the pressure of the inert gas introduced into molten metal are measured; the distance between the surface of the molten metal and the location through which the inert gas is introduced is determined on the basis of the value of the absolute pressure and the value of the pressure acting on the surface of the molten metal; and the molten metal level is electrically detected and adjusted on the basis of the above-mentioned distance. In the case of this method, the difference between the value of the absolute pressure and the value of the pressure acting on the surface of the molten metal is so minute that it is difficult to detect variations of the above-mentioned difference by means of a normal pressure gage, and therefore it is necessary to use a high-precision, costly pressure measuring instrument.
It is an object of the present invention to provide a means for solving the above-mentioned problems caused by conventional photoelectric and conduction sensors, wherein inert gas which is fed into a container for melting metallic material, for the purpose of preventing molten metal from being oxidized, is adopted as the detecting medium. It is yet another object of the present invention to provide a new method and apparatus for detecting a molten metal level inside a container for melting metallic material, wherein variations of a molten metal level are detected on the basis of variations of a liquid level inside a detector caused by a rise in the pressure inside a pipeline; and even if changes in the pressure inside the pipeline is minute, a very simple arrangement is capable of reliably detecting the rise of the surface of molten metal at all times without requiring any high-precision pressure measuring apparatus to be used.
For the purpose of achieving the above-mentioned objects, the present invention provides a method wherein communication is established by means of a gas-pipeline for inert gas between that portion of a container for melting metallic material which is above the molten metal surface inside the above-mentioned container for melting metallic material and that portion of a detector comprising a transparent tubular container which is above the liquid surface inside the above-mentioned detector, and variations of the liquid level inside the detector due to a rise in the pressure inside the gas-pipeline are detected as upward variations of the molten metal level.
Furthermore, the apparatus according to the present invention comprises: a gas-pipeline for inert gas whose open end is inserted in a container for melting metallic material, wherein the opening of the above-mentioned open end is caused to face into that portion of the above-mentioned container which is below a supply port and which is above the surface of molten metal inside the above-mentioned container; a detector comprising a transparent tubular container, in which the interior of the above-mentioned tubular container is partitioned with a transparent partition wall to constitute a double structure having an inner portion and an outer portion, a plurality of liquid chambers are thus formed, the cross-sectional area of each of the above-mentioned liquid chambers is equal to that of the other, communication is established between the lower portions of the above-mentioned liquid chambers, the interior of the above-mentioned tubular container is filled with a required quantity of detecting liquid consisting of a liquid material having a low specific gravity, the upper portion of the above-mentioned tubular container is sealed, the central liquid chamber serves as a measuring chamber, and a liquid level gage is provided in the upper portion of the above-mentioned central chamber: wherein that liquid chamber in the above-mentioned detector which serves as the measuring chamber is connected to the above-mentioned gas-pipeline to establish communication between that portion of the above-mentioned container for melting metallic material which is above the surface of the molten metal inside the above-mentioned container for melting metallic material and that portion of the above-mentioned measuring chamber which is above the surface of the detecting liquid inside the above-mentioned measuring chamber; communication is further established by means of a pipeline between that portion of the outside liquid chamber which is above the liquid surface inside the above-mentioned outside liquid chamber and that portion of the above-mentioned container for melting metallic material which is above the surface of the molten metal inside the above-mentioned container for melting metallic material; and variations of liquid levels inside both of the liquid chambers due to a pressure rise in the above-mentioned gas-pipeline can be detected as upward variations of the molten metal level.
Yet another form of the above-mentioned detector comprises: a plurality of liquid chambers consisting of a pair of transparent tubular containers disposed side by side, wherein communication is established between the lower portions of the transparent tubular containers; detecting liquid consisting of a liquid material having a low specific gravity which is disposed inside each of said liquid chambers; and a liquid level gage disposed in the upper portion of each of said liquid chambers, with the upper portion of each of the above-mentioned tubular containers sealed: wherein both of the above-mentioned liquid chambers serve as measuring chambers; one of the above-mentioned liquid chambers is connected to the above-mentioned gas-pipeline; communication is established by means of a pipeline between the rest of the above-mentioned liquid chambers and that portion of the container for melting metallic material which is above the surface of the molten metal inside the container for melting metallic material; and variations of liquid levels inside both of the liquid chambers due to a rise in the pressure inside the gas-pipeline can be detected as upward variations of the molten metal level.
In the case of such an arrangement, it is the most desirable that the inside cross-sectional area of one of the two liquid chambers be set equal to that of the other. However, in the event that the inside cross-sectional area of the liquid chamber connected to the gas-pipeline is set larger than that of the liquid chamber connected to the pipeline, then variations of the liquid levels in both liquid chambers can be easily detected. Moreover, in the event that a colored or pigmented liquid is adopted, then visual confirmation of variations of the liquid levels can be easily carried out.
Furthermore, according to the present invention, even if a slight increase takes place in the pressure inside the gas-pipeline, the surface of the. liquid in the measuring chamber reacts, resulting in the above-mentioned liquid surface lowering, while the surface of the liquid in the liquid chamber connected to the pipeline rises. Therefore, such a rise can be detected as a rise exceeding a set level of the molten metal surface.
As regards the arrangement, it is sufficient to connect the detector to the gas-pipeline for inert gas, which is a means for preventing oxidation, and to the pipeline for establishing communication with the interior of the container for melting metallic material. Consequently, the present invention can be applied widely without being restricted by internal constructions of containers for melting metallic material such as melting furnaces.

Method and apparatus for detecting molten metal level in container for melting metallic material


An apparatus for heating a blast furnace stove having a combustion region and a combustion gas outlet associated with the combustion region includes a source of lower calorific value fuel; a first pipeline for supplying the lower calorific value fuel to the combustion region; a source of air; a second pipeline for supplying the air to the combustion region; a source of oxidant comprising at least 85% by volume of oxygen; a third pipeline to supply the oxidant to the combustion region; a fourth pipeline communicating with the combustion gas outlet for conducting combustion gas away from the stove; and a fifth pipeline operable to recirculate combustion gas to the combustion region. The apparatus may operate in different modes according to which of the pipelines are placed in communication with the combustion region.

The present invention relates to apparatus for heating a blast furnace stove having a combustion region and a combustion gas outlet associated with the combustion region.
Blast furnaces are primarily but not exclusively used for the reduction of iron oxide ore to molten iron. The purpose of blast furnace stoves is to provide the blast furnace with a consistent hot-blast temperature, at a desired flow rate, in a safe and environmentally responsible manner over a protracted period of many years. The operation of a blast furnace stove is in principle simple. An air-fuel burner is typically used to burn a fuel gas (typically, predominantly blast furnace gas) and the combustion products are passed through a large mass of refractory brick that captures the sensible heat of the combustion product. Once the refractory bricks have reached the desired operating temperature the burner is shut down and cold air is passed through stove, passing over the bricks, so as to be preheated before being sent to the blast furnace as the hot-blast air. Typically, the stoves are operated in banks of three or four so that some stoves are being heated while others are providing hot blast to the blast furnace.
The blast furnace stoves may have any of a number of different configurations. Typically, each stove comprises a first vertical chamber in which combustion takes place along side a second vertical chamber in which the refractory bricks are located. Such a stove is often referred to as being of the external combustion chamber kind. Stoves in which the combustion region is housed in the refractory chamber are also known. These are called "internal" combustion stoves. In another configuration, the combustion chamber is placed on top of the refractory chamber, typically being located within a dome-shaped structure.
In current practice, there are three main approaches to try to maximise the amount of heat that can be transferred from the stove to the hot-blast. Providing a hot-blast with as high a heat content as possible reduces the coke rate for iron-making in the blast furnace. To achieve a high hot-blast temperature, the refractory or checker bricks in the stoves need to be heated to as high a temperature as is possible within the physical constraints set by the permissible dome temperature of the stove. In consequence, the calorific value of the fuel gas delivered to the burner must be capable of generating a suitably hot flame.
Blast furnace top-gas (often referred to as blast furnace gas) is conventionally the primary fuel used to heat the blast furnace stoves, but the use of this fuel has the drawback that its calorific value is variable, being strongly dependent upon the blast furnace operating practices. The variability of the blast furnace gas' calorific value is such that it is well known to blend the blast furnace gas with a higher calorific value fuel gas such as coke oven gas, converter gas or natural gas, in order to boost its heating value and generate the required flame temperature. It is alternatively known to preheat the fuel gas and air upstream of combustion by the stove burner. Indeed, the combustion gas exiting the stoves during the heating cycle typically has a temperature between 250° and 400° C. and contains about 18% of the energy input to the stoves. In some plants, this relatively hot flue gas is routed to a waste heat recovery unit where a portion of its sensible heat content is capture and used to perform the preheating. Another alternative method of heating the blast furnace stoves is to enrich the combustion air with oxygen. Adding oxygen to replace part of the combustion air increases the flame temperature as, at constant total molecular oxygen flow, the nitrogen ballast in the combustion products is reduced. Commonly, oxygen enrichment of the air is used to facilitate a reduction in the amount of coke oven, converter or natural gas needed to generate the desired flame temperature.
It is desirable to improve the operation of blast furnace stoves but in a flexible manner that is able to take account of changes in the availability and cost of fuel and other gases during an operating campaign.


An apparatus for transporting an injector assembly, such as an injector and a BOP, for coiled tubing to a wellhead may have a platform, such as a trailer, having a shaft attached thereto by at least one bracket. Pivotally on the bracket may be a boom, which may have telescopic sections, and at least one member, which may have a substantially boomerang shape. The member may be attachable to the bracket by an extendable boom fold actuator, and may be attachable to the boom via an extendable boom operating actuator. By selectively extending and contracting the boom fold actuators and the boom operating actuators, the boom may be selectively positioned between a transport mode, a vertical mode, and an operating mode. In this way, one assembly may be used to transport the coiled tubing and the injector assembly for connection to the wellhead, thus minimizing rig-up or set up time.

1. Field of the Invention
The present invention relates generally to an assembly for use in transporting devices to sites of wellbores. More particularly, this invention relates to a platform such as a trailer for transporting coiled tubing and an injector assembly to a wellhead, and for aiding in the alignment of the injector assembly at a wellhead, for the subsequent injection of coiled tubing into a wellbore.
2. Description of the Related Art
Coiled tubing may better suited for performing various downhole tasks, such as many reservoir stimulation techniques, as opposed to using solid drill string. For example, it is known to attach a downhole tool, such as a straddle packer, to coiled tubing and run the packing device downhole until the desired zone is reached. Once positioned, a well treatment such as a fracing operation or other stimulation operation may be accomplished, e.g. For example, a fluid such a fracing proppant or sand slurry may be forced from surface, through the coiled tubing string and into the zone straddled by the packer.
As an example of an operation using coiled tubing and as shown in FIG. 1, a packer P has been lowered via coiled tubing 10 into a wellbore W to force a fluid into zone Z2, while preventing fluid communication with the zone Z1 above zone Z2.
To inject coiled tubing into the wellbore, an injector assembly having an injector head typically is attached to a wellhead at surface of a wellbore. In a typical coiled tubing operation, coiled tubing is injected downhole through a wellhead by a coiled tubing injector. The injector operates to grab the coiled tubing from the spool and inject the coiled tubing into the wellbore via facing chain drives on the injector.
Generally, a Blow Out Preventor ("BOP") is used as a safety device when performing a downhole operation. The BOP is customarily used in downhole operations to control the well. For instance, if a negative differential pressure between the hydrostatic pressure of the coiled tubing fluid and the formation pressure exists, fluid may tend to escape to surface. Although various configurations and models of BOPs are known, their function is the same: to take over should the primary well control fail. Thus, when running coiled tubing, an injector assembly having a BOP is may be utilized to inject the coiled tubing off the spool and into the wellbore.
Generally, to attach the injector assembly with a BOP to a wellhead, it is known to utilize at least two trucks to align the BOP and the injector with the wellhead. For instance, in the system of FIG. 1, a first truck 1 pulling a trailer 2 is utilized for transporting the coiled tubing spool 20, the BOP 60, and the injector head 50 to the wellhead 1000. The BOP 60 and the injector head 50 may be stored separately on the back of the truck. Or the BOP 60 and injector head 50 may be preassembled and pre-stabbed with the coiled tubing 10 to minimize assembly time at the wellhead 1000. The injector 50 may comprise a gooseneck 55 as shown in FIG. 1 as an aid to align the coiled tubing 10 from the spool 20 into the injector 50.
A second truck 3 may be utilized to transport a second trailer 4 to the site. The second trailer 4 may comprises a crane having a boom 30, which may include a boom with telescopic arms. Such telescoping cranes are known to be commercially available from Furukawa UNIC Cranes from Japan or National Crane Corp. of Shady Grove, Pa., and are known to have a maximum capacity of over 66,000 pounds (29.9 Metric Tons) and a vertical reach of 170 feet (50.9 meters).
Further, when performing a some operations, a third truck or even more trucks may be utilized to accomplish the operation, for example.
The first truck 1 and the second truck 2 are positioned in relatively close proximity to the wellhead 1000 via the truck driver pulling as close as possible to the wellhead 1000. Once both the first truck 1 with trailer 2 and the second truck 3 with trailer 4 are at the wellhead, these trucks are aligned such that the boom 30 on the trailer 4 may be connected to the injector assembly to remove the injector assembly with the injector 50 and the BOP 60 from the first truck 1 and place the BOP 60 on the wellhead 100.
The BOP 60 is manually connected to the end of the arm of the boom crane 30 via a cable 40. Once the BOP 60 is set, the boom crane 30 on the trailer 4 of the second truck 3 may operate to remove the injector head 50 from a rack on the trailer 2 of the first truck 1 to connect the injector head 50 to the BOP 60.
In some cases, the injector 50 is preassembled to the BOP 60, and the injector is pre-stabbed with the coiled tubing 10 during transport. The boom 30 of the crane is attached to the injector assembly via cable 40. The boom crane 30 lifts the injector assembly via a cable 40, and an operator O at surface connects the BOP of the injector assembly to the wellhead 1000. During this connection period, the BOP and the injector assembly may sway from the cable 40 in the wind, a considerable distance above the operator O, the injector assembly weighing over 5000 pounds. It is desirable to provide a more positive connection means such that the injector assembly would be less likely to sway in the wind, which also would improve the safety of the setting operation.
The crane with the boom 30 may have a boom with telescopic arms. Further, the crane may rotate 360 degrees with respect to the bed of the trailer 4. Further, the boom itself may rotate with respect to the plane of surface, from zero degrees (i.e. horizontal) to ninety degrees (i.e. perpendicular) to the trailer.
Once the BOP 60 and injector 50 are attached to the wellhead 100, the coiled tubing 10 is injected from the spool 20 into the wellbore 100. The underground operation, such a running a straddle packer P and performing a well treatment as described above, may be performed.
Various factors may further complicate the alignment of the injector assembly with the wellhead 1000. As stated above, the BOP 60 and the injector 50 may hang or "dangle" from the boom 30 of the crane via the cable 40. Further complicating the procedure is the fact that each the BOP 60 and the injector 50 may weigh in excess of 5000 pounds, with the injector assembly hanging from the cable over thirty feet in the air, the alignment with the wellhead may be difficult. Thus, it is desired that an assembly with improved safety and security for performing the setting operation be provided. I.e. with these injectors and BOPs weighing over 5000 pounds, extending over thirty feet m the air, it is desirable to have control of the movement of the injector to improve the safety of the operation.
Further, in these prior art system, the two drivers for the first truck 1 and second truck 3 attempt to align the trailers 2 and 4 respectively proximate the wellhead 1000. Depending on the drivers' abilities, this alignment operation may prove less than ideal, and may include trial an error, thus increasing the rig up or setting time.
Further, in many some instances the wellhead is not perpendicular with surface. In others, the surface itself is not perfectly horizontal. Further, wind may act to sway the injector assembly as described above. These conditions, inter alia, may cause complications in setting the injector at the wellhead, which, in turn, may increase the rig-up time.
Similarly, when it is desired to remove the coiled tubing from the wellbore, the crane on the second truck may be used to remove the injector assembly with the BOP 60 from the wellhead 1000 via a cable 40. The injector 50 with the BOP 60 may be stored on trailer 2 of the first truck 1, in a dissembled or pre-stabbed/pre-assembled fashion as described above.
It would be advantageous to provide a system, which more positively controlled the movement of the injector assembly for alignment with the wellhead.
Other systems have been developed in an attempt to reduce the amount of operator intervention in the setting of the injector assembly on the wellhead 1000. For example, it is known to utilize a mast crane system for setting up a wellbore intervention. Such a system is the Mast Coiled Tubing Unit, known to be utilized by BJ Services Company, of Houston, Tex. With a mast unit, a self-erecting mast is brought to the wellhead by one truck. The vertical supports of the mast are positioned over the wellhead by properly positioning the trailer on the first truck with respect to the wellhead. Once in the desired location, the vertical supports contact the surface and the mast elevates the injector from eight to forty-eight feet above surface. The mast is attached to a trailer and is erected at the wellbore. Such a mast unit structurally supports the injector. As such, no crane-supported overhead load exists. Thus, fewer overhead lifts are required, as the BOPs are transported on the unit and hydraulically lifted into place.
With a mast unit, a miniature drilling mast is attached to the back of a trailer. The mast is attached in such a way that it may move vertically with respect to the trailer. Some mast units provide little adjustment with respect to the location near the wellhead. Thus, the truck must be driven relatively close to the wellhead for proper alignment. The mast unit is comprised of two vertical uprights with the injector traveling vertically within these uprights. These uprights of the mast are designed to be folded back onto the trailer, and may be placed vertically when it is desired to place the injector on the wellhead.
In some mast systems, alignment with the wellhead is provided by driving the truck around to properly position the mast with respect to the wellhead. Further, two trucks are typically utilized with the mast systems; one for the mast, and one for the coiled tubing and injector assembly. In some mast units, the injector and the BOP are affixed to the mast assembly during transportation and operation. In some mast units, the tubing reels are provided on the same trailer. Regardless, alignment may prove problematic with some of these mast units.
Thus, it is desirable to provide an apparatus for transporting an injector assembly, which may include a coiled tubing injector and a BOP, to a wellhead, and to facilitate the placement of the injector assembly on the wellhead. It is desirable that such an apparatus be quickly and positively aligned with the wellhead. It is desirable that such a system positively provides contact between the injection assembly and the wellhead such that the assembly does not dangle overhead of operators from a cable. It is further desirable that the apparatus allow the BOP and injector to be pre-stabbed with coiled tubing during transport to minimize rig-up time at the site. It is desirable to minimize the equipment and manpower required at the wellbore. Thus, it is desirable that the BOP be preassembled with the injector head to minimize rigging or set up time. It if further desirable to remove some of the human interaction, to reduce the number of operators and equipment at the wellhead, and to improve the placement accuracy of the injector assembly.
Thus, it would be desirable to provide a coiled tubing injector head and a BOP attached to a boom that can extend the assembly from a trailer to a wellhead for proper alignment. Such an assembly may decrease the rig-up and rig-down times of prior art system.
The present invention is directed to overcoming, or at least reducing the

Coiled tubing injector deployment assembly and method


A computer-implemented method includes providing a real-time environmental model of a shared virtual environment (SVE) that includes a plurality of virtual players. Display data corresponding to the SVE is transmitted to each player device. The data includes user display data that causes a display in the player device to render a portion of the SVE based on a virtual orientation of the player device and a virtual location of the virtual player in the SVE. Sensory feedback data is then transmitted to the plurality of VR devices that causes each VR device to provide a sensory indication associated with the SVE to the respective player. The sensory indication is indicative of a benefit that will be provided to a subset of the plurality of players at a predetermined future time. At the predetermined future time, the benefit is then provided to the subset of the plurality of players.

Electronic and electro-mechanical gaming machines (EGMs) are systems that allow users to place a wager on the outcome of a random event, such as the spinning of mechanical or virtual reels or wheels, the playing of virtual cards, the rolling of mechanical or virtual dice, the random placement of tiles on a screen, etc. Advances in technology have significantly changed the characteristics of products offered by the gaming industry and associated effects on user experiences. Virtual reality and augmented reality gaming involves using innovative 3-D computer-based formats with high resolution graphics that immerse the player into an interactive gaming environment as an enhancement to or a replacement of a real-world scene. Virtual reality and augmented reality technologies may enable innovative and immersive player experience.

Sensory indications for future game events for multiple players of a wagering game


A retaining apparatus is provided for mating an ignition coil to a spark plug.

Some vehicle engines implement an ignition system where a separate ignition coil is connected to each spark plug without the use of a distributor and spark plug wires in what is commonly referred to as a coil-on-plug ignition system. The coil-on-plug ignition system provides various benefits relative to other types of ignition systems. For example, the coil-on-plug ignition system allows each ignition coil a longer time to accumulate a charge between sparks relative to an ignition system where a single ignition coil provides charge to a plurality of spark plugs. Accordingly, the coil-on-plug ignition system provides a higher energy spark relative to other such systems.
FIG. 1 shows one example of an ignition system 100 having a coil-on-plug configuration for one cylinder of an engine. The ignition system 100 includes an ignition coil 102. A camshaft cover 104 forms a passage 106 where the ignition coil 102 is inserted to gain access through the camshaft cover 104 to a spark plug (not shown). The ignition coil 102 connects to a terminal of the spark plug in order to provide an electrical charge to the spark plug.
The ignition coil 102 is bolted to the camshaft cover 104 to secure the ignition coil in the passage 106 so that the ignition coil 102 remains connected to the spark plug. In particular, the ignition coil 102 comprises a mounting arm 108 that extends away from the passage 106 and protrudes over the camshaft cover 104. The mounting arm 108 comprises a threaded portion 110 for receiving a fastener (e.g., a bolt) 112. Correspondingly, the camshaft cover comprises a threaded portion 114 to receive the fastener 112. Further, the camshaft cover 104 comprises a mounting boss 116 for aligning the mounting arm 108 with the camshaft cover 104 so that the threaded portion 110 of the mounting arm 108 aligns with the threaded portion 114 of the camshaft cover 104 so that that fastener 112 can be screwed into the threaded portion 110 and further into threaded portion 114 to secure the ignition coil 102 to the camshaft cover 104.
However, the inventors have recognized several potential issues with such a configuration. For example, by bolting the ignition coil to the camshaft cover, the tolerances of each component stack up so that variations in dimensions and tolerances of the components create additional interference or reduced clearance. This in turn results in component deflection upon assembly and/or increased wear that reduces the operational life of the components. Moreover, noise, vibration, harshness (NVH) characteristics of the camshaft cover are transferred to the ignition coil resulting in reduced connection stability and/or increased wear.
In one example, the above mentioned issues may be addressed by an ignition system comprising: a spark plug comprising a spark plug terminal; an ignition coil comprising a barbed terminal; a housing covering the spark plug, the housing forming a passage for the ignition coil to access the spark plug; and a retaining apparatus comprising: a first spring clip to retain the barbed terminal; and a second spring clip to retain the spark plug terminal to mate the ignition coil to the spark plug. In one particular example, this enables the ignition coil not to be mounted to the camshaft cover, if desired.
By mating the ignition coil to the spark plug with the retaining apparatus instead of mounting the ignition coil to the camshaft cover, for example, the stack up of tolerances of the ignition coil can be reduced. In this way, the connection between the ignition coil and the spark plug can be made more stable and consistent and the operating life of the components can be increased due to reduced wear. This configuration may be especially beneficial in engines that utilize floating composite camshaft covers that are isolated from the cylinder head by an insolating layer, because the camshaft cover has a greater tendency to change position relative to the position of the spark plug as a result of NVH.
Moreover, since the ignition coil is not mounted to the camshaft cover, various mounting features of the ignition coil and the camshaft cover can be eliminated, if desired. In particular, the mounting arm and the threaded portion can be eliminated from the ignition coil and the mounting boss and the threaded portion can be eliminated from the camshaft cover. In addition, the fastener can be eliminated from the ignition system. In this way, the ignition system can be made less complex resulting in a reduction in production costs.
It will be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description, which follows. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined by the claims that follow the detailed description. Further, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Ignition coil to spark plug mating apparatus


A plurality of DC power supply modules have track pins interconnected for tracking of output voltages of the modules during power-up and normal power-down. Each module pulls down its track pin voltage in response to any fault, and detects a track pin voltage below a threshold to detect a fault communicated from any other module, to facilitate fault power-down. The track pin voltage is initially raised above the threshold for power-up. One module can be designated a master for monitoring an input voltage to the modules and for determining the track pin voltage for normal power-up and power-down.

It is frequently required to provide a plurality of different supply voltages for different parts of an electronic circuit. For example, one or more low voltage supplies of the order of 1.8, 1.5, or 1.2 volts may be required for high-speed ICs (integrated circuits) and one or more higher voltage supplies of the order of 2.5, 3.3, or 5 volts may be required for input-output functions. In order to provide the different supply voltages, for example on a printed circuit board (PCB) on which the electronic circuit may be implemented, it is known to provide a plurality of DC point-of-load (POL) or power supply modules on the PCB. For efficient operation and relatively low power dissipation, the DC power supply modules typically comprise switch mode DC-DC converters, but they may alternatively comprise linear voltage regulators, or a mix of converters and regulators.
The supply voltages produced by the power supply modules are typically required to track one another in a predetermined manner. For example, on power-up, simultaneous, ratiometric, or offset tracking may be desired for each power supply module until its output voltage reaches its respective set-point. Converse supply voltage tracking may be required for power-down.
It is known to provide relatively complex arrangements that can control DC power supply sequencing and can perform other power management functions such as monitoring. Such arrangements may be more sophisticated and expensive, and may require more connections, than desired in many applications of DC power supply modules, and also may require undesired programming for their operation.
It is also known to provide a DC power supply module with a control pin referred to as a track pin. In this case, the output voltage of the DC power supply module is limited to the lesser of the set-point of the power supply and a control voltage supplied to the track pin. The track pins of a plurality of such power supply modules can be connected together and supplied with a suitable control voltage to facilitate tracking of the different output voltages produced by the power supply modules during power-up and/or power-down. For example, the control voltage can be provided by a supervisory IC, by the output voltage of another power supply, or by an internal or external resistor-capacitor (RC) circuit.
However, such an arrangement does not provide for tracking of the output voltages produced by the DC power supply modules in the event of fault conditions. For example, in the event of a fault causing an output voltage of one power supply module to decrease rapidly to zero, this known track pin arrangement does not similarly reduce the output voltage of each other power supply module. In addition, the known arrangement does not ensure that all of the power supply modules start operating at substantially the same threshold level of input voltage.
Accordingly, there is a need for an improved method and apparatus which can provide for tracking of DC power supply module output voltages under power-up and power-down conditions and can also accommodate fault conditions.

Tracking and fault communication for DC power supply modules


The invention relates to a joining arrangement for connecting a pipe to a system, especially a hydraulic clutch disengagement system. The joining arrangement comprises a joining member which can be fixed to a final section of the pipe and is to be connected to an opposite piece that is fastened to the system. The joining member positively embraces at least one radially prominent protrusion of the pipe for fastening purposes.

Such joining arrangements are known from the state of the art. For example, these joining arrangements are used for hydraulic plug connections on coupling pressure lines, where screw connections having a fitting, for example, are provided as the joining members, which can then be screwed tightly onto a pipe made of metal, for example. It is also known that such connecting members can be attached to the pipe fixedly, i.e., not detachably, by soldering or the like.
The document DE 196 48 683 A1, for example, discloses a hydraulic cylinder having a venting element. The hydraulic cylinder which is used as a slave cylinder or master cylinder in a hydraulic disengagement system may have an opposing piece to which a joining member of a known joining arrangement is attached to connect the pipe to the hydraulic cylinder of the hydraulic clutch disengagement system.
The document DE 197 40 649 B4 discloses a plug connection for connecting pipes and hose lines. The known plug connection comprises an inner sleeve and an outer sleeve. A pipe or hose line is accommodated between the inner sleeve and the outer sleeve, whereby a pipe connection that is pushed over the outer sleeve is also provided. In the case of the connecting member and/or joining member, which is designed in multiple parts, it is possible with another component to achieve a catch engagement of the pipe connection with the outer sleeve. With the known joining arrangement, the resulting production is cost-intensive due to the multitude of components.
Another joining arrangement is known from the document DE 31 43 041, which discloses a device for detachable fastening of a hydraulic line to a hydraulic connection. The hydraulic connection, which is screwed into a housing that carries hydraulic medium, is connected to the hydraulic line via a coupling part. To attach the coupling part to the hydraulic medium connection, the coupling part must be pushed onto the hydraulic line. Then additional operations on the hydraulic line using special tools are required to reshape the end of the line so that the coupling part is connected to the hydraulic line. Finally, the coupling part is connected to the hydraulic connection by a catch engagement.
In particular when using the joining arrangement for connecting a coupling line to a hydraulic disengagement system, the connection arrangement has a significant influence on the manufacturing costs. Therefore it is necessary to construct the joining arrangement with the simplest possible design so that manufacturing costs can be lowered.

Joining arrangement for connecting a pipe to a system


The bulk volume of large numbers of loose, separated, multiply bent, irregularly shaped scrap sheet metal is temporarily reduced, for transportation and storage of the metal for recycling purposes, by compressing the metal into temporary, compacted wafers formed of successively compacted layers. The apparatus includes a load chamber which is axially aligned with a compression chamber and a reciprocating ram which passes through the chambers towards an anvil plate which closes the discharge end of the compression chamber. A pre-determined quantity of loose pieces is placed within the load chamber. The reciprocating ram compresses the pieces of that batch into a thin layer. Successive batches are compressed into overlapping layers which are temporarily bound together, face-to-face, to form a unitary wafer, by temporarily bending and intertwining the peripheral edges of the layers. The layers are subsequently separated for recycling by depositing into a melt furnace.

This invention relates to an apparatus and a method for temporarily compacting multiply bent or convoluted, generally large pieces of sheet metal scrap resulting from manufacturing processes, such as sheet metal drawing procedures or sheet metal stamping processes and the like, which generate large quantities of irregularly shaped scrap pieces. Such scrap metal can be recycled by melting the scrap within conventional melt furnaces.
Typical scrap, ferrous metal trimmings from metal drawing or punching or stamping or the like processes, are multiply bent or convoluted, are irregular in shape, and are generally of substantial size. An example of such scrap pieces is the trimmings from edges of large sheets of steel whose center portions are deep drawn to form large sections of automotive vehicle bodies. Conventionally, the loose scrap metal pieces are piled into a container for transporting the scrap pieces to a place where the pieces may be stored and, ultimately, re-melted for recycling. The collected pieces, because of their convoluted or multiply bent, irregular shapes, occupy considerable volume. Thus, there is a substantial cost involved in transporting the large volume of collected pieces.
In order to reduce the volume of such collected pieces of scrap, attempts have been made to flatten their multiple bends and to compact the scrap pieces together by use of equipment which compresses the pieces together into large bales or blocks. Although this compression reduces the problems of transporting the otherwise larger volume of loose pieces, other problems result from that compression when melting the scrap. When such large bales or blocks, which can be a number of cubic feet in size, are put into a melt furnace, the length of time required for melting, and the amount of heat energy needed for melting, the compacted, dense bales or blocks, is substantially greater than that required for melting loose pieces of scrap. In general, loose pieces expose far more surface areas than a compacted block. Thus, the loose pieces of scrap are better and more quickly exposed to the heat of the furnace and to the pool of molten metal in the furnace. That results in quicker melting of the pieces. Also, conventional compression or baling equipment is relatively slow in operation and is large and expensive.
Prior attempts to reduce the volume of the scrap during transportation, and simultaneously to replace both conventional baling and transporting loose pieces of irregular, convoluted, scrap sheet metal pieces, involved flattening convoluted or multiply-bent pieces between heavy rollers. These loose, flattened pieces occupy much less volume than a random mixture of loose multiply-bent or convoluted pieces which are produced in manufacturing processes.
Another way of reducing the bulk volume of sheet metal pieces of scrap has been to utilize ram type equipment which compresses quantities of loose, multiply bent, scrap pieces directly into containers. An example of equipment which compresses scrap pieces into containers in which the compressed scrap pieces are transported, is disclosed in U.S. Pat. No. 6,418,841, issued Jul. 16, 2002, for a "System and Method for Compacting and Transporting Scrap Metal" invented by Jonathan A. Little and Donald R. Schomisch.
It would be desirable to have equipment and a method for continuously processing large, irregular, loose pieces of scrap metal to meet "mill ready" specifications (i.e. ready for melting), which eliminates some of the costly transportation and processing expenses and which would also improve the efficiency and speed of processing substantial quantities of scrap material that are continuously generated in large volume manufacturing processes.
Compacting loose pieces together into a bale or block reduces the bulk volume of the material, which reduces the expenses for transportation and storage of the scrap material. But, as set forth above, the trade-off is that such compacting increases the cost of melting the material as compared to melting loose, separate pieces. Hence, it is desirable to melt loose pieces which have more exposed surface areas as contrasted with the less exposed surface areas of compacted bales or blocks. That is, because the surface areas of the separated pieces of scrap metal are directly exposed to the heat so that they melt faster in a conventional electric arc melt furnace than when compacted into blocks which directly expose only much smaller outer surface areas to the heat.
The present invention is concerned with providing a method and apparatus which can continuously receive large quantities of irregularly shaped and multiply bent sheet metal pieces, and rapidly compress these pieces together into temporary, loosely or moderately compacted wafers or biscuits or slabs. These temporary wafers can be rapidly disassembled, after transporting them, into their constituent separate pieces when fed into a melt furnace.
The apparatus includes a ram-type press which compacts successive batches of individual, i.e. loose, sheet metal scrap pieces into layers which, in turn, are assembled together into thicker wafers or slabs. These wafers are sometimes referred to as biscuits. The individual layers and their respective pieces are temporarily held together by interlocked portions of their peripheral edges and by the interlocking of their adjacent, contacting, bent portions. The wafers, which are formed by a number of overlapped layers, can be disassembled, for example, by suspending the wafers horizontally and shaking or vibrating them so that the weight of their layers cause the layers and their constituent loosely or moderately compacted scrap pieces to pull apart and to fall down under the influence of gravity. Hence, the scrap pieces can be transported as unitary compacted groups which substantially reduce the volume during transportation, yet the pieces can later be fed into a furnace as separated loose pieces. The disassembly can be accomplished directly above a melt furnace so that separated pieces are fed into the furnace.

Apparatus and method for temporarily compressing loose, multiply bent, pieces of scrap sheet metal into compacted wafers

Professional Management Disposal Systems L.L.C.


An apparatus for dispensing a plurality of powders or flowable materials, such as colorants for paint, caulking or grout or components of cosmetics, comprising a plurality of containers for holding the powders or flowable materials, a plurality of metering pumps, connected to a container or having a connector for releasably connecting a container to the respective pump, wherein the capacity of the metering pump is selectable.

1. Technical Field
An apparatus for dispensing a plurality of flowable materials, such as colorants for paint, dye, caulking or grout or components of cosmetics, and to a method of compounding flowable substances are disclosed.
2. Background of the Related Art
A prior art apparatus of this type is disclosed in U.S. patent application 2003/0230355. This document pertains to an interactive cosmetic body powder selection system having a point of sale dispenser. The system includes a cosmetic powder dispenser that contains a plurality of different shades, tints or hues of colors or pigments, which can be dispensed in pre-selected proportions to create a custom color selection. A user-interactive system is provided at a point-of-sale for allowing a user to choose or dispense a color, effect, or both. Information about the selection is employed for dispensing the appropriate proportions of ingredients. Preferably the ingredients are dispensed manually into a powder canister having an integrated brush in fluid communication with the canister. In another embodiment, the system is automated.
U.S. Pat. No.4,959,947 relates to an apparatus for the production and packaging of a compound mixture, in which extremely accurate and rapid weighing-out, proportioning and packaging of individual components are achieved, is provided. For this, filling stations (4 to 6) are equipped with combined discharge, weighing and transfer devices (22), which allow single-component treatment. In colunm 4, lines 25 to 32 it is stated that "The first type of filling station 4 (individual vessels 1 to 4) illustrated in FIG. 1 has a discharge device 23 which is composed of two electronically controlled worm conveyors 24 arranged above one another and of an electronically controlled shutoff valve 25. The double worm conveyor serves for matching the proportioning capacity to the material to be conveyed or to the amount to be weighed out from the feed vessel 7."
German Utility Model 299 24 013 relates to a metering device for a powder, such as aluminum powder for making cellular concrete, which comprises a relatively large screw for generating a relatively large mass flow and a relatively small screw, which receives material from the relatively large screw.
An apparatus for and method of relatively accurately and relatively quickly dispensing different amounts of flowable materials such as powders, slurries and liquids are disclosed.
In an embodiment, the said amounts vary over a wide range.
The disclosed apparatus is of a relatively robust construction.

This patent is subject to a terminal disclaimer.

Apparatus for dispensing a plurality of powders and method of compounding substances


An apparatus includes an operational amplifier circuit comprising at least one operational amplifier and a feedback circuit coupled between the output terminal and input terminal of the operational amplifier circuit and configured to apply a feedback gain to an output signal at the output of the first operational amplifier. The apparatus further includes a variable compensation capacitor coupled to the output terminal of the operational amplifier circuit and configured to vary a capacitance thereof responsive to the feedback gain.

Embodiments of the inventive subject matter relate to image signal processing circuits and electronic devices incorporating the same and, more particularly, to operational amplifier circuits used to process image signals from, for example, a pixel sensor array.
An image sensor is a device that captures an image using a semiconductor reaction to light. Recently, with the development of complementary metal oxide semiconductor (CMOS) technology, CMOS image sensors are being widely used. Some conventional CMOS image sensors use correlated double sampling (CDS) and output a signal resulting from the CDS, e.g., a difference between a reset signal and an image signal, in a digital format.
A CMOS image sensor circuit may include a programmable gain amplifier (PGA), an analog-to-digital converter (ADC circuit), and a sense amplifier (SA). The PGA, the ADC circuit, and the SA typically include operational amplifier circuits. The ADC circuit may include a sample-and-hold amplifier (SHA) and a digital-to-analog converter (DAC). The SHA and the DAC may also include operational amplifier circuits.
Such operational amplifier circuits may include a negative feedback amplifier. The gain of a negative feedback amplifier generally depends on circuit components forming the operational amplifier circuit. When the gain of the negative feedback amplifier approaches infinity, the output of the operational amplifier circuit may oscillate.
The stability of the operational amplifier circuit is generally influenced by phase margin (PM). FIGS. 1A and 1B are Bode plots of frequency response of a conventional operational amplifier circuit. Referring to FIGS. 1A and 1B, frequencies at which feedback loop gain and phase are 1 and −180 degrees, respectively, are important to the stability of the operational amplifier circuit. The frequency at which the feedback loop gain is 1 is referred to as a gain crossover. The frequency at which the feedback loop phase is −180 degrees is referred to as a phase crossover.
It is desirable that the gain crossover be less than the phase crossover in order to provide stable operation of the operational amplifier circuit. Stability can be improved by shifting the phase crossover away from the origin or shifting the gain crossover toward the origin. The stability of a system can be measured in terms of PM. The PM is defined as PM=180°+∠βH(ω=ω1), where ω1 is the gain crossover frequency.
When the gain crossover is shifted toward the origin, the stability of the operational amplifier circuit is increased, but the bandwidth is generally decreased. As a result, high-frequency signals are attenuated. When the bandwidth is increased, the operational amplifier circuit can realize higher speed. When an operational amplifier circuit that can realize a wide bandwidth is used, high sampling speed may be achieved in communications and image processing applications, such as in mobile communication equipment, asynchronous digital subscriber loop (ADSL), digital camcorders, and high-definition television (HDTV) and imaging systems.

Amplifier apparatus and methods using variable capacitance dependent on feedback gain


A safety controller having a total worst case propagation delay, exceeding the required propagation delay required by a safety process, may be used to control the safety process by monitoring actual delays in signal processing in the safety controller and moving to a safety state if a signal delay exceeds an amount less than the total worst case propagation delay.

The present invention relates to industrial controllers used for real-time control of industrial processes, and in particular to "high reliability" or "safety" industrial controllers appropriate for use in devices or with devices intended to protect human life and health.
Industrial controllers are special-purpose computers used in controlling industrial processes. Under the direction of a stored, controlled program, an industrial controller examines a series of inputs reflecting the status of the controlled process and changes a series of outputs controlling the industrial process. The inputs and outputs may be binary, that is, on or off, or analog, providing a value within a substantially continuous range. The inputs may be obtained from sensors attached to the controlled process, and the outputs may be signals to actuators on the controlled process.
"Safety systems" are systems intended to ensure the safety of humans working in the environment of an industrial process. Such systems may include the electronics associated with emergency-stop buttons, light curtains, and other machine lockouts. Traditionally, safety systems have been implemented by a set of redundant circuits separate from the industrial control system used to control the industrial process with which the safety system is associated. Such safety systems have been "hardwired" from switches and relays including specialized "safety relays" which provide comparison of redundant signals and internal checking of fault conditions such as welded or stuck contacts.
Hard-wired safety systems using duplicate wiring have proven cumbersome in practice, in part because of the difficulty of installing and connecting hardwired components and duplicate sets of wiring, particularly in complex control applications, and in part because of the difficulty of troubleshooting and maintaining a hard-wired system whose logic can be changed only by re-wiring.
For this reason, there has been considerable interest in developing industrial controllers that may implement safety systems using a program simulating the operation of the physical components in hard-wired safety systems. Industrial controllers are not only easier to program but may provide reduced installation costs by eliminating long runs of redundant wiring in favor of a high speed serial communication network and by providing improved troubleshooting capabilities. U.S. Patent application 60/373,592 filed Apr. 18, 2002; Ser. No. 10/034,387 filed Dec. 27, 2001; Ser. No. 09/667,145 filed Sep. 21, 2000; Ser. No. 09/666,438 filed Sep. 21, 2000; and Ser. No. 09/663,824 filed Sep. 18, 2000, assigned to the assignee of the present invention, describe the implementation of safety systems using industrial controller architectures, and are hereby incorporated by reference.
When an industrial controller is used to implement a safety process in lieu of hard-wired devices, it is important that the speed of propagation of safety signals through the components of the industrial controller is well characterized. Importantly, safety processes requiring response speeds that exceed those possible with the industrial controller, because of signal propagation delay, must be avoided.
The propagation delay of a given signal through an industrial controller will vary as a function of network loading, computational complexity, and other often unknown factors. For this reason, the propagation delay of an industrial controller is normally characterized by summing the worst-case delays of each of the components of the industrial controller in the signal chain from input circuit through processor to the output circuit. Each of these components may also have a watchdog timer ensuring that the delay at the component does not exceed this worst case delay value and notifying the user and entering a safety state should this restraint be violated by any given signal.
Worst-case delay values must be conservatively estimated and therefore, when they are added together, the total worst case delay is substantially longer than the typical propagation delay of the industrial controller. Further because there is some statistical independence in the actual propagation delays at the components, worst-case delays at some components, will typically be offset by lesser delays at other components. Nevertheless, a simple summing of worst-case delay values is used because actual propagation delay of a given signal is known only too late to avoid unsafe operation.

Safety controller with safety response time monitoring


To provide an organic electroluminescent device which suppresses crystallization of a material to be used in an organic electroluminescent device and which is good in luminous characteristics, device drive durability and storage stability, the organic electroluminescent device has at least one organic layer including a light emitting layer between a pair of electrodes, wherein the light emitting layer contains a compound represented by formula (1) defined in the specification and a light emitting material.

As one of large causes to deteriorate the durability of an organic electroluminescent device (hereinafter sometimes referred to as "light emitting device" or "organic EL device"), there is enumerated a problem of crystallization of an organic material. If the crystallinity of an organic material to be used in the device is high, the organic material in the device causes crystallization due to the storage over a long period of time or the generation of heat in driving the device, resulting in a problem of causing device breakage such as short circuit of the device.
JP-A-2001-196183 describes an organic electroluminescent device containing a compound which is included in a compound represented by formula (1) of the invention as described later. However, this document neither describes nor suggests that a phosphorescent material is used as a light emitting material and that a compound represented by formula (1) is used as a host material (combined use with other light emitting material). Further, this document neither describes nor suggests that L in formula (1) of the invention is a trivalent or polyvalent aromatic hydrocarbon group, a trivalent or polyvalent aromatic heterocyclic group, a trivalent or polyvalent thiophene structure-containing group, or a trivalent or polyvalent carbazole structure-containing group.


A truck having a cab with a full access engine enclosure is disclosed in which the routine maintenance points of the engine may be accessed from within the cab without having to move the seats. The floor of the cab is formed with an opening disposed between the seats or tilt the cab. A housing with upwardly extending walls is affixed to the floor surrounding the opening. The upper extent of the housing is formed with a large opening extending forwardly and rearwardly of the seats. Doors are hinged to the housing for closing and opening the housing opening.

1. Field of the Invention
The present invention relates to a truck and truck cab and, more particularly, to a truck cab having an engine enclosure with an opening giving full access to the routine maintenance points of the truck engine from inside the cab.
2. Description of the Related Art
Cab-over-engine trucks are well known in which the truck engine is situated generally beneath the floor of the truck cab. Such trucks have been constructed with tilt cabs in which the cab is hinged to the front of the truck chassis so that the cab may be tilted forward to allow full access to the engine beneath the cab. In order to provide some degree of access to the engine without having to tilt the cab, truck cabs have been provided with relatively small interior openings which allow limited access to the engine below. These small openings do not allow access to all of the routine maintenance points of the engine from inside the cab.
Other approaches to engine access have included hinged floor panels located at least partially beneath the seats of the cab. While such panels enable a greater degree of access to the engine without having to tilt the cab, they require that the seats be mounted so that they can be moved out of the way before the panel may be opened.

Truck having cab with full access engine enclosure


Magnetic fluid is inserted between slip rings of a rotor and brushes of a stator. The magnetic fluid is held by magnetic force generated by permanent magnets and yokes mounted on the stator, so as to be sidable relative to the slip rings. In this state, in accordance with rotation of the rotor, the brushes and the slip rings are rotated without direct contact with each other via the magnetic fluid. Thus, the brushes and the slip rings are electrically connected to each other.

The present invention relates to a slip ring mechanism adapted for use in extreme conditions, for example, space and a vacuum.
Generally, spacecraft, such as an artificial satellite, is equipped with various space apparatuses, for example, an antenna apparatus including a rotary driving portion. Such an apparatus on spacecraft includes a well-known slip ring mechanism as means for transmitting or receiving a signal including power to or from the rotary portion. In the slip ring mechanism, a rotor having slip rings is coaxially attached to the rotation axis of a rotary portion. A stator having brushes is attached to a fixture support. When the rotor is rotated in accordance with the rotation of the rotary portion, the brushes of the stator are slid on the slip rings of the rotor. As a result, a signal is transmitted between the rotor and the stator.
When the aforementioned slip ring mechanism is used in space of a very high temperature and vacuum, it is difficult to use oil or grease as a lubricant as is used on the ground.
There are two types in slip ring mechanisms for use in space: one is sliding type, and the other non-sliding type. In the case of a slip ring mechanism of sliding type, the slip rings and brushes are made of self-lubricant material, such as gold or silver, to transmit signals between the rotor and the stator. In the case of a slip ring mechanism of non-sliding type, conductive fluid, e.g., mercury, is interposed between the slip rings and the brushes, so that the slip rings may not directly slide on the brushes. In this state, signals are transmitted between the rotor and the stator.
However, the slip ring mechanism of sliding type has the following drawbacks. The lifetime of this type is short, because the rings or brushes are liable to wear and the electric performance is easily lowered due to its structure.
In the slip ring mechanism of non-sliding type, the structure of arrangement of the conductive fluid is very complicated. Moreover, since it is difficult to completely prevent the fluid from leakage, the mechanism has only low reliability.
These problems occur also in extreme conditions on the ground, for example, in a vacuum, where it is difficult to use oil or grease as a lubricant.


A heat dissipation device (30) includes a heat dissipation member (31), a positioning member (33) and a mating member (34). The heat dissipation member includes a fin set (311) and a post (312) in the fin set. The post extends through the positioning member and is mated with the mating member so that the positioning member is positioned between the fin set and the mating member.

1. Field of the Invention
The present invention relates to a heat dissipation device, and particularly to a heat dissipation device having a central post which contacts an electronic component to be cooled.
2. Description of Prior Art
Electronics technology continues to boom unabated. Numerous modern electronic devices such as central processing units (CPUs) of computers operate at high speed and thus generate large amounts of heat. The heat must be efficiently removed from the CPU; otherwise, abnormal operation or damage may result. Typically, a heat sink with good thermal conducting capability is mounted onto the CPU to remove heat therefrom.
FIG. 3 shows a heat dissipation device for removing heat from an electronic component 10. The heat dissipation device comprises a fan 1, a fin member 2 and a central post 3. The fan 1 is mounted on the fin member 2 via a fan holder 4. The fin member 2 is formed by bending a continuous metal plate whereby each fin is U-shaped. The fin member 2 is radially arranged in a ring shape to define a central receiving hole 5 for closely receiving the central post 3 therein. The post 3 forms a circumferential projection 6 at an end thereof. In use of the heat dissipation device, a piece clip 7 with a central hole circles over the post 3. The fin member 2 receives the post 3 in the central receiving hole 5 and is bonded to the post 3. The clip 7 is engaged with the protrusions 9 of a socket 8 so that the projection 6 of the post 3 is pressed by the clip 7 toward the electronic component 10. Thus, the post 3 of the heat dissipation device is attached to the electronic component 10 for transferring heat therefrom.
However, the clip 7 circles over the post 3 prior to the engagement of the post 3 with the fin member 2. This obstructs the engagement of the post 3 with the fin member 2. During fitting of the clip 7 to the protrusions 9, force exerts on the clip 7 which is prone to be interfered with the electronic component 10. This takes a risk of damaging the electronic component 10. Furthermore, the clip 7 is not powerful enough to prevent the heat dissipation device, especially these having bulky volumes, from swaying during shock or vibration. In short, the heat dissipation device cannot be easily and safely positioned to the electronic component 10.

Fu Zhun Precision Ind. (Shenzhen) Co., Ltd.


Azeotrope-like compositions comprising trifluoromethane, carbon dioxide and sulfur hexafluoride are stable and have utility as refrigerants for heating and cooling.

This invention relates to azeotrope-like or constant-boiling mixtures of trifluoromethane, carbon dioxide and sulfur hexafluoride. These mixtures are useful as refrigerants for heating and cooling.
Fluorocarbon based fluids have found widespread use in industry for refrigeration applications such as air conditioning and heat pump applications. Vapor compression is one form of refrigeration. In its simplest form, vapor compression involves changing the refrigerant from the liquid to the vapor phase through heat absorption at a low pressure and then from the vapor to the liquid phase through heat removal at an elevated pressure.
While the primary purpose of refrigeration is to remove energy at low temperature, the primary purpose of a heat pump is to add energy at higher temperature. Heat pumps are considered reverse cycle systems because for heating, the operation of the condenser is interchanged with that of the refrigeration evaporator.
Certain chlorofluoromethane and chlorofluorethane derivatives have gained widespread use as refrigerants in applications including air conditioning and heat pump applications owing to their unique combination of chemical and physical properties. The majority of refrigerants utilized in vapor compression systems are either single components fluids or azeotropic mixtures.
Azeotropic or azeotrope-like compositions are desired as refrigerants because they do not fractionate upon boiling. This behavior is desirable because in the previously described vapor compression equipment with which these refrigerants are employed, condensed material is generated in preparation for cooling or for heating purposes. Unless the refrigerant composition exhibits a constant boiling point, i.e. is azeotrope-like, fractionation and segregation will occur upon evaporation and condensation and undesirable refrigerant distribution may act to upset the cooling or heating.
The art is continually seeking new fluorocarbon and hydrofluorocarbon based azeotrope-like mixtures which offer alternatives for refrigeration and heat pump applications. Fluorocarbon and hydrofluorocarbon based azeotrope-like mixtures are of particular interest because they are considered to be environmentally safe substitutes for the presently used fully halogenated chlorofluorocarbons (CFC's) which are suspected of causing environmental problems in connection with the earth's protective ozone layer.
Substitute refrigerants must also possess those properties unique to the CFC's refrigerants including similar refrigeration characteristics, chemical stability, low toxicity, non-flammability, and efficiency in-use. The latter characteristic is important in refrigeration and air-conditioning especially where a loss in refrigerant thermodynamic performance or energy efficiency may have secondary environmental impacts through increased fossil fuel usage arising from an increased demand for electrical energy. Furthermore, the ideal CFC refrigerant substitute would not require major engineering changes to conventional vapor compression technology currently used with CFC refrigerants. Mathematical models have substantiated that hydrofluorocarbons, such as trifluoromethane (HFC-23), will not adversely affect atmospheric chemistry, being a negligible contributor to ozone depletion and to green-house global warming in comparison to the fully halogenated species. HFC-23 alone is not useful as a refrigerant because of a reduction in low evaporator temperature capability.
R-503 is an azeotropic blend which consists of trifluoromethane (HFC-23) and chlorotrifluoromethane (CFC-13), a fully halogenated chlorofluorocarbon. (U.S. Pat. Nos. 2,101,993 and 2,641,579). Since R-503 contains the fully halogenated species CFC-13, the use of R-503 will eventually be phased out with the phase out of CFC-13. It is believed that the novel compositions of this invention may often be used as an alternative to R-503.
JP-3,255,189-A published Nov. 14, 1991 discloses a refrigerant composition of HFC-23 and n-pentane.

Azeotrope-like compositions of trifluoromethane, carbon dioxide and sulfur hexafluoride


The invention provides a high speed two-dimensional discrete cosine transform circuit which can reduce the number of addition operations for rounding to one time. The two-dimensional IDCT circuit calculates M.times.N-point two-dimensional inverse discrete cosine transforms wherein M.times.N is equal to 2.sup.2n, and includes an M.times.N two-dimensional IDCT operator for calculating two-dimensional inverse discrete cosine transforms as matrix vector products of a transform matrix of MN rows and MN columns and MNth-order input vectors, a shift operator for shifting results of the calculation of the M.times.N two-dimensional IDCT operator rightwardly, and an adder for adding 2.sup.n-2 to a discrete cosine coefficient from among discrete cosine transform coefficients to be inputted to the M.times.N two-dimensional IDCT operator. An output signal of the shift operator is outputted as a circuit output signal of the two-dimensional IDCT circuit.

1. Field of the Invention
This invention relates to a two-dimensional IDCT circuit which affects two-dimensional inverse discrete cosine transforms (IDCT's) used for processing of signals such as image signals.
2. Description of the Related Art
As augmentation in performance of microprocessors and signal processors proceeds, those processors can be used to realize image signal processing. Above all, with a microprocessor which has a multiplier or a product sum operator built therein, since a product sum operation can be effected using the same clock number as that for addition and subtraction operations, in order to raise the speed of processing, it is desirable not only to decrease the number of multiplication operations but also to minimize the sum of the numbers of addition and subtraction operations and product sum operations.
In order to realize two-dimensional (inverse) DCT by means of a microprocessor or a signal processor, it is a common practice, because of a restriction in the number of internal registers, to first calculate one-dimensional (inverse) DCT in the direction of a row and store results once into an external memory and then read out the results of the processing in the direction of a row from the memory and perform a one-dimensional (inverse) DCT. In this instance, in order to prevent an increase of the calculation amount or the hardware amount, it is a common practice to process the results of the calculation in the direction of a row with a single precision when it is stored into the external memory. Consequently, errors are produced in calculation. One of the methods of suppressing the total number of product sum operations and addition and multiplication operations while suppressing such operation errors is disclosed in "A Study on Fast 2D (I)DCT Algorithm", Collection of Drafts for the Engineering Sciences Society of the Institute of Electronics, Information and Communication Engineers of Japan in 1995, p.88.
FIG. 10 is in block diagram showing an exemplary one of a conventional two-dimensional IDCT circuit. Referring to FIG. 10, an M.times.N two-dimensional IDCT operator 2 receives M.times.N (M and N are natural numbers) DCT coefficients as inputs thereto and effects M.times.N-point two-dimensional inverse discrete cosine transforms. The M.times.N two-dimensional IDCT operator 2 calculates to the kth bit of the fraction part, and results of the calculation of the M.times.N two-dimensional IDCT operator 2 are rounded to integers by an adder 19 and a shift operator 3. To this end, the adder 19 adds 1 to the k-1th bit as counted from the least significant bit for all of output data of the M.times.N two-dimensional IDCT operator 2. The shift operator 3 shifts the outputs of the adder 19 rightwardly by k bits.
In the conventional circuit described above, in order to round results of calculation calculated to the kth bit of the fraction part, the adder 19 adds 0.5 to all of the M.times.N data which are the results of the calculation of the M.times.N two-dimensional IDCT operator 2. Therefore, M.times.N addition operations are required.

Two-dimensional IDCT circuit with input adder out output shifter for reducing addition operations during rounding-up


A hard film is formed of a material having composition indicated by a chemical formula: (TiaAlbVcSidBf) (C1−eNe), in which subscripts a, b, c, d, f and e indicate atomic ratios of Ti, Al, V, Si, B and N, respectively, and meet relational expressions: 0.02≦a≦0.5, 0.4<b≦0.8, 0.05<c, 0≦d≦0.5, 0≦f≦0.1, 0.01≦d+f≦0.5, 0.5≦e≦1 and a+b+c+d=1. The hard film is harder than and more excellent in wear resistance than TiAlN films and conventional (TiAlV) (CN) films.

1. Field of the Invention
The present invention relates to a hard film, a method of forming the same, and a target for hard film formation. More particularly, the present invention relates to a wear-resistant hard film for improving the wear resistance of cutting tools, such as carbide tips, drills and milling cutters, machine parts, and dies for processing metals by plastic working, a method of forming the hard film, and a target used as a source material.
2. Description of the Related Art
Conventional cutting tools of cemented carbides, cermets or high-speed steels have been coated with a hard film of TiN, TiCN or TiAlN to improve the wear resistance of the cutting tools. Hard films of titanium nitride, titanium carbide and titanium carbide-nitride generally used for coating cutting tools for high-speed cutting and for cutting hard workpieces, such as workpieces of hardened steels have been replaced by films of Ti—Al composite nitride (hereinafter referred to as "TiAlN") excellent in wear resistance. Addition of a third element to a two-element material, such as TiAlN, has been made in recent years in an attempt to improve the properties of the two-element material. Films of TiAlVN or (TiAlV) (CN) disclosed in, for example, JP-A 3-120354, JP-A 10-18024, U.S. Pat. No. 5,981,049 and U.S. Pat. No. 6,296,928 exhibit excellent cutting performance in cutting workpieces of materials having low hardness, such as S50C (JIS). The cutting performance of those prior art films in cutting workpieces of hard materials, such as quenched SKD (JIS) is not necessarily satisfactory. It is desired to develop films excellent in wear resistance and having higher hardness to cope with progressively increasing demand for high-speed cutting operations at higher cutting speeds. A hard film proposed in JP-A 2002-337006 is formed of a material containing at least one of Al and metals of Groups IV, V and VI, and Si, and at least one of nonmetallic elements, i.e., N, B, C and O. The description of the prior art hard film mentions only a Si content of 50% or below in connection with the optimum composition of the material. Actually, hard film having a cutting ability exceeding that of the conventional TiAlN film cannot be formed of a material prepared by simply combining the foregoing elements.
The present invention has been made in view of the foregoing circumstances and it is therefore an object of the present invention to provide a hard film having excellent wear resistance and having a high hardness higher than that of the conventional TiAlN film or (TiAlV) (CN) film, a method of forming the hard film, and a target for forming the hard film.

Hard film, method of forming the same and target for hard film formation

Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)


A backlight unit that makes it sure to assemble many optical members in a casing in a right order with their right attitude in its assembly stage is provided. Each of the optical members to be assembled in a predetermined order has a protruding part including at least one protrusion. A count of the protrusions of each member is increased according to the predetermined assembly order. The casing has a depressed part for receiving the protrusions of the members, the depressed part including notches or depressions corresponding to the protrusions of the optical members. Each of the notches or depressions has a depth in a stacking direction that varies according to stacking state of the optical members. The notches or depressions may be formed to penetrate through the casing to thereby confirm easily the order and attitude of the assembled members after the assembly operation.

1. Field of the Invention
The present invention relates to a backlight unit and a Liquid-Crystal Display (LCD) device using the backlight unit. The invention is applicable to any other display device than the LCD device if it comprises sheet- or plate-shaped optical members arranged in a casing, for example, a display device employing an organic EL (ElectroLuminescence) element as a backlight.
2. Description of the Related Art
The LCD device has been extensively used as a monitor of the so-called Office Automation (OA) apparatus or television (TV) set because of its characters such as compactness, thinness, and low power-consumption. The LCD device comprises as its main components a LCD panel having a pair of opposing transparent substrates and a liquid crystal layer interposed between the substrates, and a backlight unit for generating backlight illuminating the panel. The backlight unit comprises as its main components a light source, optical members (e.g., a light-guiding plate, a diffusion sheet, a lens sheet, and a polarization sheet) for converting the light emitted from the source to uniform illumination light, and a casing for holding and/or covering the light source and the optical members.
The above-described optical members have their own assembling orders in the casing, which are defined in advance. Moreover, the attitude or layout of these members with respect to the casing, such as the front and back, the top and bottom, and the left and right of the respective members, is also defined beforehand. However, the appearance of these members is similar and therefore, these members are likely to be placed at a wrong order and/or in a wrong direction. As a result, there arise unfavorable conditions or states, such as degradation of luminance, and non-uniform distribution of luminance. To confirm the right assembling order and the right attitude of these optical members after the assembling operation of the backlight unit is completed, a technique as shown in FIGS. 1A to 1C was developed. This technique was disclosed in the Patent Document 1 (the Japanese Non-Examined Patent Publication No. 11-352476 published in 1999), in particular, on pages 2 to 4 and FIG. 1.
As shown in FIGS. 1A and 1B, ear-like parts 118a and 118b are respectively formed on a first lens sheet 117a and a second lens sheet 117b in their predetermined regions outside the angle of view in such a way that the parts 118a and 118b are not entirely overlapped on each other. On the other hand, an eliminated or depressed part 120 is formed on a frame-shaped casing 119 to receive the ear-like parts 118a and 118b of the sheets 117a and 117b. When the sheets 117a and 117b are assembled in the casing 119 in a predetermined order, the parts 118a and 118b are overlapped in the state as shown in FIG. 1C, where the part 118a is partially seen through the central gap or slit of the part 118b. Thus, the assembling order of the first and second lens sheets 117a and 117b can be discriminated by observing in a specific direction the parts 118a and 118b inserted into the depressed part 120 of the casing 119.
By using the above-described technique disclosed by the Patent Document 1, the count and inserted order of the lens sheets 117a and 117b can be visually inspected after the assembling operation of the backlight unit is completed. However, with this configuration, the depressed part 120 of the casing 119 has a size large enough for receiving both of the ear-like parts 118a and 118b and therefore, the sheets 117a and 117b may be arranged in an unfavorable order. As a result, whether or not the assembling order of the sheets 117a and 117b is right cannot be judged in the assembling stage of the backlight unit. If some problem or malfunction is visually found after the assembling operation of the backlight unit is completed, the unit needs to be reassembled.
Moreover, with the above-described configuration disclosed by the Patent Document 1, when the count of the lens sheets is limited to approximately two, whether the assembling order of the lens sheets is right can be judged by visually checking the state of the overlapped parts 118a and 118b. However, when the count of the lens sheets used is equal to three or more, the overlapping state of the parts 118a and 118b will be complicated. Therefore, it is not easy to judge the rightness of the assembling order of the lens sheets from the overlapping state of the parts 118a and 118b. In particular, optical members such as the lens sheets, the light-guiding plate, the diffusion sheet, and the polarization sheet are all translucent and thus, it will be more difficult to judge the rightness of the assembling order of the optical members.

Backlight unit and liquid-crystal display device using the same


An adaptive array apparatus includes a control unit 50 and a plurality of radio units 10˜40 that each have a modulator 11, a transmission circuit 12, a switch 13, a phase detecting unit 14, a reception circuit 15, and a demodulator 16. For each radio unit 10˜40, the control unit 50 compensates a phase amount for generating a directivity pattern used for an output signal according to a difference in phase shift amounts between a transmission subsystem and a reception subsystem.

To raise transfer efficiency, digital communication devices that transfer information by modulating a carrier wave using a digital information signal (baseband signal) have been developed in recent years.
In digital communication, frequencies can be more efficiently used by raising the transfer speed and converting single frequencies into multichannels for use by several users. Raising the transfer speed, however, leads to deterioration in quality due to fading.
A number of techniques to counteract this problem have been developed. A representative technique is the adaptive array method. This method adaptively generates a directivity pattern using a plurality of antennas and generates an electromagnetic wave so that it only reaches a specified user. First, consider an adaptive array apparatus that has four communication subsystems that each include a transmission circuit, a reception circuit, and an antenna. Separate directivity patterns for transmission and reception can be generated for each communication subsystem by adjusting the gain and phase of each transmission circuit during transmission and by adjusting the gain and phase of each reception circuit during reception. The adaptive array method is described in detail in Adaptive Signal Processing for Spatial Regions and Its Technical Applications (in "Transactions of the Institute of Electronics and Communication Engineers of Japan") Vol. J75-B-II No. 11, November 1992.
To perform bidirectional communication using the adaptive array method, it is desirable to have directivity patterns formed by both devices in communication. When this is applied to mobile communication, however, the physical limitations on the size of the mobile devices and the number of antennas used by them make it effectively impossible for mobile devices to form a directivity pattern. Accordingly, the base station forms separate directivity patterns for both transmission and reception. This means that during transmission, the base station forms a directivity pattern that is the same as the ideal directivity pattern that was formed during reception and transmits signals.
The adaptive array method has a problem in that it has been difficult for the base station to form the same directivity pattern during reception and transmission. A directivity pattern is formed by adjusting the gain and phase for each antenna. However, even if transmission is performed with the same phase as was used during reception, differences exist in the propagation characteristics (in particular, phase shift characteristics) of the reception circuit and transmission circuit. These differences have prevented the formation of the same directivity patterns for reception and transmission. The differences in propagation characteristics between the transmission circuit and reception circuit are due to the differences in circuit construction. These differences would still be present even if the same circuit construction were used, due to inconsistencies in the circuit components. This is to say, inconsistencies in the characteristics of actual circuit components lead to inconsistencies in radio circuits that are formed using such components.

Adaptive array apparatus and compensation method for compensating a phase difference used for generating a directivity response pattern


Bacteria-responsive core-shell nanofibers and a process for the preparation thereof are described. The nanofibers release of an antibacterial agent in response to the presence of bacteria. The core of the nanofiber comprises a biocompatible polymer together with an antibacterial agent such as a quaternary ammonium compound, for example benzyl dimethyl tetradecyl ammonium chloride (BTAC). Surrounding the core is shell comprised of a bacterially degradable polymer, which is susceptible to break-down by bacterial enzymes such as lipase, or to acidic pH conditions. The shell may comprise, for example, polycaprolactone (PCL) and poly(ethylene succinate) (PES). The nanofibers may be incorporated into wound dressings.

Wound infection is a global healthcare issue that affects the healing process. Appropriate wound dressing material can reduce the risk of infection by reducing or eliminating the invasion of pathogens. The use of antibacterial materials or agents in wound dressings can reduce risk of infection.
One approach to wound healing involves exposure of the wound to antibacterial drug release using systems that continuously elute an antibacterial agent, even if there is no bacterium present. This unnecessary release of an antibacterial agent is poorly timed with the need for the agent, and may cause undesirable cytotoxicity to the subject. Such cytotoxicity may impart delays in the healing process. Systems involving a constant and indiscriminant elution may result in a depletion of the antibacterial agent before exposure to bacteria occurs, and consequently may be ineffective when needed.
It is desirable to provide materials for use in wound healing that provide antibacterial properties when needed, in the presence of bacteria.