A gas hydrate production apparatus capable of reacting a raw gas with a raw water to thereby form a slurry gas hydrate and capable of removing water from the slurry gas hydrate by means of a gravitational dewatering unit. This gravitational dewatering unit is one including a cylindrical first tower body; a cylindrical dewatering part disposed on top of the first tower body; a water receiving part disposed outside the dewatering part; and a cylindrical second tower body disposed on top of the dewatering part, wherein the cross-sectional area of the second tower body is continuously or intermittently increased upward from the bottom.

A gas hydrate is a solid hydrate having a structure in which a gas is trapped in a cage made of water molecules. The gas hydrate is stable under, for example, atmospheric pressure at a ten-several ° C. below zero. For this reason, its utilization has been studied as alternative means to transporting and storing natural gas in a form of liquefied natural gas (LNG). The gas hydrate can be produced under relatively easily achievable conditions of temperature and pressure, and can be stored stably as described above.
Accordingly, when natural gas extracted from a gas field is subjected to an acid-gas removal process, acid gas such as carbon dioxide (CO2) and hydrogen sulfide (H2S) is removed therefrom. Then, the natural gas is temporarily stored in a gas storage section. Thereafter, in a generating process, this natural gas is reacted with water to undergo hydration reaction, and thereby a gas hydrate is formed. This gas hydrate is in a slurry form mixed with water. In a dewatering process subsequent to the generating process, unreacted water mixed therein is removed. After undergoing a regenerating process, a cooling process and a depressurizing process, the gas hydrate is enclosed in a vessel such as a container. After that, the gas hydrate is stored in a storage unit under conditions adjusted to a predetermined temperature and pressure. As described above, the gas hydrate is in a slurry form including surplus water in the generating process. Thus, the storage or transportation of the gas hydrate without any modification requires an extra cost for that water amount. Against this problem, proposed is a natural-gas-hydrate forming method in which a slurry gas hydrate is forced to be dewatered with a screw-press dewatering system (for example, Japanese patent application Kokai publication No. 2003-105362).
Meanwhile, this screw-press dewatering system has a double structure of: an inner wall processed into a mesh form; and a case disposed outside and constituting an outer shell of the inner wall. The screw-press dewatering system removes water through the mesh-processed inner wall by forcing a slurry natural gas hydrate to move forward with a screw shaft mounted within the inner wall. Accordingly, during dewatering (condensation), a large amount of the natural gas hydrate together with water passes through the mesh holes of the inner wall, reducing the recovery rate of natural gas hydrate. Moreover, the rotating of the screw shaft in high torque incurs an additional cost. Furthermore, such high torque is developed inside the dewatering unit that is under a high pressure. Accordingly, the entire equipment is overloaded, and the screw shaft has to be sealed under conditions from high pressure to atmospheric pressure.
In order to eliminate such problems, the present inventors have proposed a gravitational dewatering method utilizing gravity, unlike the conventional forcing dewatering technique. Nevertheless, the diameters of upper and lower gravitational dewatering towers are made the same. For this reason, the following problems may occur, when there is an increase in the resistance in a dewatering zone that is above a dewatering part disposed to the gravitational dewatering tower, the dewatering part being made of a metal mesh. For example, an ejection force of the slurry pump that conveys a gas hydrate slurry to the gravitational dewatering tower is increased. Moreover, the gravitational dewatering tower is clogged by a gas hydrate. Otherwise, a liquid surface (water level) at the dewatering part is elevated, resulting in an insufficient dewatering. These problems, in some cases, make a stable operation impossible with a constant dewatering rate being maintained. Furthermore, various gas hydrate production apparatuses have been proposed so far. One of the gas hydrate production apparatuses has a double structure of an inner cylindrical container and an outer cylindrical container. The space between these containers is made as a conveying path for a formed gas hydrate (see Japanese patent application Kokai publication No. 2004-10686).
Nevertheless, in this apparatus, the outer cylindrical container is required to have a pressure-tolerable structure that does not contribute to gas hydrate formation. As a result, the size of the equipment is increased, and the cost is also increased. Moreover, the gap between the outer cylindrical container and the inner cylindrical container is filled with a gas, and problems occurs that it is difficult to remove heat of the inner cylindrical container caused by the formation of a gas hydrate, and that it is difficult to achieve efficient cooling from the outside. When the gas hydrate thus formed has a high adhesive property dependent on the degree of a percentage of water adhered to the gas hydrate, or the like, another problem occurs that the gas hydrate cannot be conveyed smoothly because the gas hydrate is stuck to a wall surface of the container.
Additionally, in FIG. 5 of the above publication, proposed is an apparatus provided with: a vertical screw conveyor formed as squeezing the top of a gas hydrate formation container; and a horizontal screw conveyor. The apparatus is to convey a formed gas hydrate. Nonetheless, this apparatus also has a problem that the gas hydrate thus formed cannot be discharged smoothly because the gas hydrate is stuck to the inner surface of the formation container.
On the other hand, according to a gas-hydrate dewatering method described in Japanese patent application Kokai publication No. 2001-342473 (Patent Document 3), firstly, a gas hydrate slurry extracted from a formation container is guided to a pressure dewatering device such as a screw press to conduct physical dewatering. Then, the gas hydrate slurry thus physically dewatered is guided and transferred to a screw conveyor, and a raw gas is incorporated thereinto. Thereby, the raw gas and water adhered to the gas hydrate are reacted with each other, and hydration dewatering is conducted. As a result, a gas hydrate having a less amount of water adhered thereto is obtained. In such a hydration dewatering method as described in Patent Document 3, a physically dewatered gas hydrate is stirred with the screw to thereby react a raw gas with water adhered to the gas hydrate, and the gas hydrate is dewatered. Nevertheless, the method has a limitation in the contacting efficiency between the water and the raw gas. Accordingly, a high dewatering rate cannot be obtained.
In contrast, considered is a fluidized-bed dewatering method. In this method, a raw gas is blown to a gas hydrate that has been subjected to physical dewatering to form a fluidized-bed. The raw gas and water adhered to the fluidized gas hydrate are reacted with each other, so that hydration dewatering is conducted. According to this method, the contacting efficiency between the water and the raw gas is high, and thereby a high dewatering rate can be obtained.
A dewatering rate hardly matters when the hydration dewatering is conducted by mechanically stirring a gas hydrate slurry that has been subjected to physical dewatering as in Patent Document 3. Nevertheless, when, for example, fluidized-bed dewatering is conducted, it is necessary to increase a dewatering rate after the physical dewatering in order to guarantee a predetermined fluid state. However, in the conventional physical dewatering, a sufficient dewatering rate cannot be obtained. As a result, there is a problem that options for hydration dewatering in a later process are limited.

Gas hydrate production apparatus and dewatering unit

Mitsui Engineering & Shipbuilding Co., Ltd.


The invention disclosed includes both a method and apparatus for affixing an optic fiber tip in position with respect to a fiber communications circuit. In one embodiment of the method, a glass positioning member is located proximate the tip of the optic fiber. In another step, the glass positioning member is affixed to the fiber at a first position with respect to the fiber tip. The glass positioning member is also affixed in a second position with respect to the carrier. In a more detailed embodiment, the method of the present invention includes positioning the optic fiber through a channel of the glass positioning member. Heat is applied to the glass positioning member causing it to soften such that its channel collapses around and fuses to the fiber. In still further detail, the fused positioning member/fiber are affixed to a block, and the block is fused to a carrier. Alignment steps are taken during the fusing steps to locate the tip of the fiber in the desired position relative to the fiber communications circuitry.

The use of fiber optic technology in the communications industry continues to increase. As is known in the art, fiber optic communications provide numerous advantages such as increased bandwidth, less noise, lower signal-to-noise ratio requirements, and lower error rates. In addition, the use of fiber optic cable relative to metallic conductors permits a much larger traffic of communication to occupy the same space previously required by metallic conductors.
As known in the art, communication of signals through an optic fiber is accomplished by placing communications circuitry at the tips of both ends of the optic fiber. FIG. 1a illustrates a perspective view of certain components of such a system. Specifically, FIG. 1a illustrates a carrier 10 which is commonly disposed within a fiber optics package (shown in FIG. 1b). As known in the art, carrier 10 supports various components including a thermistor 12 and a back-wave detector 14. Carrier 10 further supports a U-shaped subcarrier 16. A submount 18 is disposed on top of subcarrier 16 and supports a laser 20.
Carrier 10 further includes an integral extension 21 which supports an adjustment post 22. A small mass of solder (not shown) supports a fiber retaining slab 24 on top of adjustment post 22. Slab 24 includes a longitudinal groove 26 on the order of 0.01 inches in width. An optic fiber 28 extends from a sleeve 30 and is retained within groove 26. The tip 32 of fiber 28 extends inwardly beyond the edge of slab 24 and immediately proximate laser 20. Thus, laser 20 can communicate signals to and from fiber 28 by either sensing signals or transmitting signals to tip 32 of the fiber.
FIG. 1b illustrates a perspective and cutaway view of carrier 10 when disposed within a prior art fiber optics package 34. Package 34 is typically a parallelepiped in shape having a length on the order of 1.0 inch and a width and height on the order of 0.75 inches. Package 34 is carefully constructed to hermetically house various components, including carrier 10. A ferrule 36 permits access through a hole or "pass through" in one side of package 34. Sleeve 30 passes through ferrule 36, thereby permitting optic fiber 28 to extend into the interior of package 34. Typically, solder 38 or an alternative sealant is used at the interface between sleeve 30 and ferrule 36 so that contaminants may not pass via this interface into the interior of package 34. A thermal electric cooler 39 supports carrier 10 and its associated componentry. In addition, package 34 houses an integrated circuit 40 which connects in various manners to the componentry of carrier 10, and also to a series of package pins 42. A pair of power conductors 43a are connected to respective power pins 43b. Thus, signal interaction to the communications circuitry and power supply to thermal electric cooler 39 may be accomplished external from package 34 by accessing pins 42 and 43b.
In the prior art embodiment of FIGS. 1a-b, optic fiber 28 is commonly affixed within retaining slab 24 by use of solder (for a metalized fiber) or epoxies (typically, for a non-metalized fiber). Specifically, either of these materials are used to form deposits 44 and 46 along slab 24 to retain fiber 28 along groove 26. While performing their respective retention function, each of these materials provides various drawbacks and potential problems in connection with the overall system. For example, as is known in the art, solder tends to move or creep over time due to stress. As another example, solder creates a known ratcheting effect due to fluctuations in temperature. Thus, both the solder used as deposits 44 and 46 as well as the solder between post 22 and slab 24 may tend to change position over the life-span of the system. Such a change correspondingly moves the otherwise fixed position of tip 32 of optic fiber 28. As is known in the art, tolerances for movement of tip 32 are typically only on the order of 0.1 to 1.5 microns. Naturally, therefore, excessive movement of tip 32 is unacceptable and may reduce or eliminate the ability of the system to communicate along optic fiber 28. Conductive epoxy and like materials also suffer due to their corrosive and/or contaminating effects. In addition, quite often these materials produce gaseous byproducts which may interfere with the sensitive operation of laser 20. Thus, these materials also present a risk to the long term reliability of the system of FIGS. 1a-1b.
It is therefore an object of the present invention to provide a method and apparatus for precisely affixing an optic fiber tip in position with respect to a fiber communications circuit.
It is a further object of the present invention to provide such a method and apparatus for reducing the possibility of subsequent movement of an optic fiber tip with respect to its associated communications circuit.
It is a further object of the present invention to provide such a method and apparatus for reducing the amount of contaminants implemented when affixing the tip of an optic fiber proximate its associated communications circuit.
It is a further object of the present invention to provide such a method and apparatus for providing improved axial and radial adjustment of the tip of an optic fiber with respect to its associated communications circuit.
Still other objects and advantages of the present invention will become apparent to those of ordinary skill in the art having reference to the following specification together with its drawings.

Method and apparatus for affixing an optic fiber tip in position with respect to a fiber communications circuit


A sensor of weak magnetic fields with magnetoresistive effect features a metallic multilayer formed by alternating magnetic and non-magnetic metals. In order to detect weak fields, a sensor is described wherein a magnetic field is coupled by an anti-ferromagnetic type coupling with a first neighboring magnetic layer and by a ferromagnetic type coupling with a third neighboring magnetic layer, so that there is frustration of coupling. The first and third magnetic layers are blocked by their strong coercive field. The sensor finds particular application to detection on magnetic media.

1. Field of the Invention
The present invention relates to a sensor of weak magnetic fields, with magnetoresistive effect, and more specifically to the structure of the layers of materials that constitute such a sensor.
The term "sensor with magnetoresistive effect" is used to designate a sensor using the variation of resistivity of at least one material that forms it as a function of the variation of a magnetic field. A weak magnetic field is the field radiated by the tape of a magnetic recording for example.
2. Description of the Prior Art
Various types of sensors with magnetoresistive effect are known and are implemented in systems for the reading of magnetic recordings such as tapes, drums and diskettes. These sensors comprise a monolithic part, a block made of a ferromagnetic alloy with high magnetoresistance, which is placed in the magnetic circuit of a reading head which reproduces the variations of the electrical resistance of the magnetoresistive sensor while a recording flows past. The alloys most frequently used, at present, are nickel-based ferromagnetic alloys such as NiCo, NiFe (Permalloy) which have high magnetoresistance but which, at ambient temperature, give a relative variation in resistance of only a few percent.
Sensors of greater sensitivity have been developed more recently: they use a phenomenon known as "giant magnetoresistance" which develops when the sensitive element of the sensor is constituted by a multilayer of alternating magnetic and non-magnetic metals. In this multilayer, the magnetic layers have ferromagnetic (parallel) type coupling, outside any magnetic field, or anti-ferromagnetic (anti-parallel) type coupling under a magnetic field, and the transition from one state to the other occurs on a small interval of a field. The drawback of these multilayer sensors is the excessive value of the magnetic field needed for the "reversal" to make the magnetizations of the layers transit from the parallel state to the anti-parallel state. A strong magnetic field is needed when the layers have regular thicknesses and are coupled to one another. The energy of the "reversal" is equal to the sum of the energies used for the coupling of one layer with the two adjacent layers.

Sensor of weak magnetic fields, with magnetoresistive effect


An aesthetically pleasing, monolithic cast concrete picnic table (10) is provided which presents a generally horizontal table section (12), horizontal bench sections (14,16) generally along and below the side margins of the table section (12), and a central connecting section and base (18,20) joining the table and bench sections (12,14,16) and permitting placement of the table (10) on a support surface. Preferably, the table (10) presents a generally H-shaped footprint, with unobstructed spaces (117) beneath the bench sections (14,16) on either side of the connecting section (18). The table (10) can be rapidly cast using a form (118) permitting easy separation of the table (10) via jacks (126).

1. Field of the Invention
The present invention is broadly concerned with a unitary, monolithic, cast concrete picnic table especially designed for use in parks or other public places to minimize theft and vandalism. More particularly, the invention pertains to such a cast picnic table which includes a horizontal table section, a pair of bench sections, and a central connecting section permitting the table to be cast as a monolithic structure and moved to a use location as a unitary body.
2. Description of the Prior Art
Picnic tables designed for use in public places such as parks and lakes are subject to theft or destruction, and replacement or repair of such tables is a significant expense. One type of prior table is in the form of metal or synthetic resin table and bench sections interconnected with metallic tubular members. These tables are generally relatively lightweight, and therefore can be readily picked up and stolen.
It has also been known in the past to provide cast concrete picnic tables, but these are generally in the form of separate tables and benches which must be separately cast, moved to a use location, and secured in place. While such assemblies are difficult to steal owing to the weight thereof, their cost is considerable because of the separate casting and setup operations required. In addition, they are generally quite unattractive in appearance.
There is accordingly a need in the art for an improved, monolithic cast picnic table which can be fabricated, transported and set in place as a unitary body, while nevertheless exhibiting characteristics of weight, strength and durability allowing efficient use of the cast table in public venues.

Kansas State University Research Foundation


A process for preparing polyolefin resin pre-expanded particles comprising imparting expandability to polyolefin resin expanded particles having a crystal structure which shows two melting points in a DSC curve and heat expanding expanded particles having expandability, in which the relation between heat expansion temperature and the amount of a fusion preventing agent being attached to the surface of the polyolefin resin expanded particles is represented by the inequality: t-T.sub.V .ltoreq.49.1C-27.0 (t is heat expansion temperature, C is the amount of the fusion preventing agent being attached to the surface of the polyolefin resin expanded particles and T.sub.V is saddle temperature between two peaks showing two respective melting points in the DSC curve), and t is within the temperature range represented by the inequality: T.sub.L -30.ltoreq.t.ltoreq.T.sub.V (T.sub.V is the same as defined above and T.sub.L is lower melting point of the two melting points). According to the process, mutual fusion of the expanded particles and increase of open cell ratio of the pre-expanded particles can be prevented at the same time, expansion efficiency can be increased, and polyolefin resin pre-expanded particles having high expansion ratio can be prepared.

The present invention relates to a process for preparing polyolefin resin pre-expanded particles, and more particularly to a process for preparing polyolefin resin pre-expanded particles which can be preferably used as, for instance, a raw material for an internal die expansion molded article.
Conventionally, when polyolefin resin pre-expanded particles are prepared, there is well known a process for preparing polyolefin resin expanded particles, comprising dispersing resin particles together with a dispersant into an aqueous disperse medium in a closed container, introducing a volatile blowing agent thereto, then heating the resin particles to at lowest softening temperature of the polyolefin resin and releasing the resin particles into a lower pressure atmosphere than internal pressure of the closed container.
For instance, there is already published a process for preparing polyolefin resin pre-expanded particles having a special crystal structure which shows two melting points in a DSC curve obtained by a differential scanning calorimetry, by using the above process for preparing polyolefin resin expanded particles (see, for instance, Japanese Unexamined Patent Publication No. 176336/1984 and Japanese Unexamined Patent Publication No. 183832/1988). Furthermore, there is already published a method for improving expansion ratio of the above polyolefin resin pre-expanded particles having a special crystal structure with retaining a closed cell structure. In this method, expandability is imparted to the polyolefin resin pre-expanded particles and then, the particles are heated (see Japanese Unexamined Patent Publication No. 23428/1985 and Japanese Unexamined Patent Publication No. 90228/1985).
In Japanese Unexamined Patent Publication No. 23428/1985, there is disclosed a process for preparing pre-expanded particles having higher expansion ratio than that of base non-crosslinked propylene random copolymer pre-expanded particles having a specific range of expansion ratio and cell number and having a crystal structure which shows higher temperature peak on a higher temperature point than a point of intrinsic peak of the base resin in a DSC curve. In this process, expandability is imparted to the non-crosslinked propylene random copolymer pre-expanded particles and then, the particles are heat expanded.
In Japanese Unexamined Patent Publication No. 90228/1985, there is disclosed a method comprising a step of imparting expandability to polypropylene resin pre-expanded particles having the same special crystal structure as that of the pre-expanded particles disclosed in Japanese Unexamined Patent Publication Nos. 176336/1984 and 183832/1988 and having decreasing speed coefficient of internal pressure "k" of at most 0.30, a step of heating the polypropylene resin pre-expanded particles in a closed container to temperature "T" (.degree. C.) represented by the inequality: EQU Tm-65<T<Tm-30
wherein Tm is melting finishing temperature of the base resin, a step of keeping as it is, a step of opening the edge of the container and a step of releasing the polypropylene resin pre-expanded particles into a lower pressure atmosphere than internal pressure of the container.
However, all technologies in these methods relate to a polypropylene resin, in particular, ethylene-propylene random copolymer. Accordingly, technologies using the other polyolefin resin are not disclosed.
As to heat temperature of the pre-expanded particles, as usual, it is described that vapor having vapor pressure of 0.8 to 1.5 kg/cm.sup.2 (G) (116.degree..about.127.degree. C.) or hot air having temperature of at lowest 100.degree. C. is preferably used (see Japanese Unexamined Patent Publication No. 23428/1985). Also, it is described that the pre-expanded particles are heated at temperature "T" (.degree. C.) represented by the inequality: EQU Tm-65<T<Tm-30
wherein Tm is melting finishing temperature of the base resin (see Japanese Unexamined Patent Publication No. 90228/1985). However, although the pre-expanded particles having a special crystal structure are used, it is not disclosed that crystal characteristic of the pre-expanded particles is related to heat temperature of the pre-expanded particles to accomplish the objects.
During heat expansion of the thus polyolefin resin expanded particles, in the case that heat temperature of the expanded particles is too high, open cell ratio of the obtained pre-expanded particles increases. In the case that the thus obtained pre-expanded particles are used for internal die mold, it is forecasted that mechanical strength of the produced molded article remarkably lowers or mutual fusion of the expanded particles is generated to cause short shot during feeding of the expanded particles into a molding machine. These phenomena are mentioned in the above Publications.
Then, the inventors of the present invention have earnestly studied as to heat expansion and carried out the following examination. An ethylene-propylene random copolymer having the above temperature "Tm" of 157.degree. C. was used as a base resin and subjected to the general procedure to give expanded particles. The obtained expanded particles were sufficiently washed with water and an acidic aqueous solution to give expanded particles having the above special crystal structure (expansion ratio: 11.3 times, average cell diameter: 300 .mu.m, decreasing speed coefficient of internal pressure "k": 0.15). The obtained expanded particles having the special crystal structure were heat expanded with vapor having vapor pressure of 1.5 kg/cm.sup.2 (G) (about 126.degree. C.) to give pre-expanded particles (expansion time: 30 seconds). However, although pre-expanded particles having high expansion ratio and a closed cell structure could be certainly prepared, mutual fusion of the expanded particles was generated to cause short shot of the expanded particles during molding.
When pre-expanded particles are prepared by a heat expansion method, as one of the effective means for heightening expansion ratio of the obtained pre-expanded particles, it can be proposed that a resin layer on the surface of expanded particles is softened together with heightening heat temperature and internal pressure of the expanded particles. However, in the case that mutual fusion of the expanded particles is once generated as mentioned above, substantially, heat temperature cannot be heightened any more, so that expansion ratio of the obtained pre-expanded particles cannot be heightened.
On the other hand, in a process for producing a polyolefin resin expansion molded article comprising filling a molding machine with the above pre-expanded particles having the special crystal structure and subjecting the pre-expanded particles to heat fusion with vapor to give an expansion molded article having the desired shape, the amount of attachment on the surface of the pre-expanded particles is known as one of factors exerting an influence upon molding fusion property (see, for instance, Japanese Unexamined Patent Publication No. 57838/1992).
That is, in a process for preparing polyolefin resin expanded particles comprising dispersing polyolefin resin particles into an aqueous disperse medium in a closed container, introducing a volatile blowing agent thereto, then heating the resin particles to at lowest softening temperature of the polyolefin resin and releasing the resin particles into a lower pressure atmosphere than internal pressure of the closed container, inorganic powder which is called dispersant or fusion preventing agent is added to the aqueous disperse medium together with the polyolefin resin particles, the inorganic powder is attached to the surface of the polyolefin resin particles to prevent mutual fusion of the resin particles in the aqueous disperse medium, and this surface attachment is washed and removed during or after preparation of pre-expanded particles to improve molding fusion property.
For instance, in the process described in Japanese Unexamined Patent Publication No. 57838/11992, 3 parts (parts by weight, hereinafter referred to the same) of powdery tricalcium phosphate as a dispersant and 0.12 part of sodium n-paraffinsulfonate are added to 100 parts of ethylene-propylene random copolymer pellet, and a method for washing pre-expanded particles just after preparation is changed, so that the amount of attachment (mainly, tricalcium phosphate) on the surface of the pre-expanded particles is changed. However, in the case that the amount of this attachment is at least 3300 ppm, there is a problem that molding fusion property remarkably lowers, so melt bonding ratio of the obtained molded article becomes 0%. This problem is pointed out in this Publication.
Then, the inventors of the present invention have firstly considered that mutual fusion of expanded particles during heat expansion can be prevented or restrained in accordance with adjustment of the amount of attachment on the surface of the pre-expanded particles. So, by the inventors, there has been carried out heat expansion experiment comprising increasing the amount of attachment on the surface of the base expanded particles under the entirely same condition as in the case that mutual fusion of expanded particles has been generated at vapor pressure of 1.5 kg/cm.sup.2 (G) during the above heat expansion. As a result, it has been found that mutual fusion of expanded particles has not been generated even at vapor pressure of 3 kg/cm.sup.2 (G) (=143.degree. C.).
In addition, by using the other polyolefin resin or composition thereof, such as ethylene-propylene random copolymer, ethylene-.alpha.-olefin copolymer or a resin composition prepared by adding an ethylene ionomer to ethylene-.alpha.-olefin copolymer, which has different melting finishing temperature each other, the same experiment as mentioned above has been carried out. As a result, it has been found that at lower temperature than T.sub.L -30 (.degree. C.) (T.sub.L : lower melting point of the two melting points of base pre-expanded particles), expansion ratio by heat expansion has been improved only a little. Also, it has been found that at higher temperature than T.sub.V (.degree. C.) (T.sub.V : saddle temperature between two peaks showing two respective melting points), mutual fusion of expanded particles has been generated having no relation to melting finishing temperature of base resin (composition) or no relation to the amount of attachment on the surface of base expanded particles, or open cell ratio of the obtained pre-expanded particles has become at least 20% by heat expansion. Accordingly, it has been found that retention of good moldability has been difficult.
Furthermore, at the temperature range from T.sub.L -30 (.degree. C.) to T.sub.V (.degree. C.), there has been examined the relation between the amount of attachment on the surface of the expanded particles and t (.degree. C.) (t: heat expansion temperature at which mutual fusion of expanded particles has been generated). As a result, as to all kinds of polyolefin resin expanded particles, surprisingly, it has been found that there has been the linear relation between the upper limit of the temperature represented by t-T.sub.V (.degree. C.) (at the same temperature as this upper limit or higher temperature than this upper limit, mutual fusion of expanded particles has been generated) and the amount of a fusion preventing agent being attached to the surface of the expanded particles, so that the present invention has been completed.
The present invention has been accomplished in consideration of the above knowledge.
An object of the present invention is to provide a process for preparing polyolefin resin pre-expanded particles having high expansion ratio with retaining closeness of cell and without generation of mutual fusion of expanded particles in accordance with a heat expansion method by using the above polyolefin resin expanded particles having a special crystal structure.
This and other objects of the present invention will become apparent from the description hereinafter.

Process for preparing polyolefin resin pre-expanded particles


The invention shows the method to create a high accuracy topographical scale model for the purpose of science by using multi layered/laminated materials. The invention is based on and involves the following steps:                The geometry and the data of terrain are measured, collected, and recorded;        The data is entered into a computer and design components are added, if needed;        Based on these data a three-dimensional surface is created;        A block of multi-layered/laminated materials made of a combination of veneers, or machinable dividers/layers, laminated one on the top of another, is constructed.

Topographical, three-dimensional models provide a physical representation of the landform.
The models can be created using a copy of the drawings of the terrain as a reference during model construction or by using a three-dimensional modeling program on a computer to generate a model data.
Traditionally, topographical models are made from a high-density foam, plastic foam, acetate, etc. The models must be enclosed to prevent people from touching. The purpose of these models is to see the features of terrain but not to touch them.
The most important disadvantages of the physical models are the inability to measure the elevational differences of the terrain in any point of the model and the lack of accuracy.
To show the elevational differences of the terrain, some of the models are created in stair-stepping style. Other models, are created by printing detailed photo-realistic images on the models carved from a high-density foam. These models can provide a physical representation of the terrain, but they are not made for easy Visual measuring because of the lack of an elevation reference, and they are not comparable to the accuracy of the three-dimensional computer-generated drawing.

Manufacturing of three-dimensional topographical scale models for the purpose of science

Abstract: Based on the three-dimensional surface, a program for a C.N.C machine is generated;                Based on the program, the C.N.C. machine cuts/removes the excess material from the block of multi-layered materials. The three-dimensional surface, contour lines, elevations, outlines, and edges are then exposed automatically and are easy visually measurable.


Provided herein are bone grafts and methods of making and using the same, as well as products and kits that include such bone grafts. In particular, bone grafts are provided that include osteogenic stem cells in a mix of osteoinductive demineralized bone matrix and osteoconductive cortico-cancellous chips.

Bone generally has the ability to regenerate completely, e.g., after a fracture but requires a very small fracture space or some sort of scaffold to do so. Bone grafting is a surgical procedure that replaces missing bone to repair bone fractures that are very complex, fail to heal properly, or pose a significant health risk to the patient.
Bone grafts may be autologous (bone harvested from the patient's own body, often from the iliac crest), allograft (cadaveric bone usually obtained from a bone bank), or synthetic (often made of hydroxyapatite or other naturally occurring and biocompatible substances) with similar mechanical properties to bone. Most bone grafts are expected to be reabsorbed and replaced as the natural bone heals over a few months' time.
Bone grafts are osteogenic if they contain viable cells that are capable of bone regeneration. The current gold standard in bone graft substitutes for spine and long bone applications is autograft (i.e., using the patient's own tissue), followed by allografts. Autografts are considered osteogenic, as they contain a high number of bone forming cells. However, autographs may have limited availability and they are limited by donor site morbidity. Also, autografts may require multiple surgeries. Allografts are limited by the large variability in performance due to source and processing steps.
There is a need to produce superior bone grafts that are osteogenic and/or are able to enhance bone regeneration throughout the bone healing phase.

Bone grafts and methods of making and using bone grafts


A particle charging method and apparatus are provided. An ion source is applied to a particle laden flow. The flow is introduced into a container in a laminar manner. The container has at least a first section, a second section and a third section. The first section includes wetted walls at a first temperature. A second section adjacent to the first section has wetted walls at a second temperature T2 greater than the first temperature T1. A third section adjacent to the second section has dry walls provided at a temperature T3 equal to or greater than T2. Additional water removal and temperature conditioning sections may be provided.

Electrostatic deposition and electrical mobility size separation of airborne particles are widely used techniques for the collection or analysis of airborne particles. These methods require that the particles to be collected or analyzed carry an electric charge. However, for very small particles with diameters less than about 50 nm, adding an electrical charge is difficult. In this size range exposure to a bipolar ion source provides singly charged particles, but the charging efficiency is low. For particles with diameters of 50 nm, just 17% of the particles will acquire a positive charge, with an approximately equal number acquiring a negative charge. At 10 nm the fraction of particles charged with a single polarity is ˜4%, and at 3 nm this drops to less than 2%. Unipolar charging can improve charging efficiencies for particles above about 10 nm, but it also becomes ineffective at smaller particle sizes.
One technique that has been used to increase the charging efficiency of these small particles is condensation-enhanced particle charging, wherein the particles are grown through condensation, charged and re-evaporated. Some prior art techniques have used butanol condensation to prepare highly charged particles in the 10-30 nm size range. Others have used condensation of glycol to enhance the charging of sub-20 nm particles. Still others have explored this approach with water condensation, albeit for larger (80-130 nm) particles. Limitations of these existing methods are: (1) the contamination of the particle through the use of organic materials as the condensing vapor, (2) addition of multiple electrical charges to each particle, and (3) inability to charge particles below about 10 nm.


Entities of a wireless communication network adjacent to a given sending entity, i.e. entities of the network from which the sending entity is able to receive messages are identified. Among the adjacent entities, a minimum constellation associated with the sending entity is further identified as the smallest set of entities adjacent to the sending entity and included in a circle centered on the sending entity such that at least three of the entities of the set form a convex polygon circumscribing the sending entity. The transmitting power of the sending entity is then adjusted to a value sufficient for the messages sent by the sending entity to reach all the entities of the minimum constellation associated therewith.

The invention concerns the field of wireless networks, made up of a plurality of entities intercommunicating, for example by radio channel.
More specifically, the invention relates to a method of adjusting the sending power—also called the transmitting power—of the network entities. It also relates to a wireless communication unit intended to form an entity of such a network.
The invention applies particularly to ad hoc networks, i.e. networks that do not have a pre-existing infrastructure for sending data from one entity to another.
It should be remembered that, in the field of radio waves, any signal transmitted by a sending entity to a destination entity is subject to an attenuation proportional to a power of the distance separating these entities (in practice, this power is between 2 and 6).
That is why the transmitting power of the sending entity must be sufficient for the signal effectively to reach the destination entity.
It is not, however necessary for the signal to reach the destination entity directly (this case being referred to as direct sending): it can, in practice, pass through a third party entity of the network, called an "intermediate node" or "routing node" (this case being referred to as indirect sending).
It should be noted that, in an ad hoc network, each entity can alternately serve as sending entity, destination entity or intermediate node.
In order to provide network connectivity, that is, ensure that, whatever the sending and destination entities, there is always a path enabling the message to be delivered to the receiving entity from the sending entity, it is necessary for each sending entity of the network to know the location of its adjacent entities, and vice versa.
An adjacent entity of a sending entity is any entity, for which the sending entity is near enough to receive a direct signal.
Each sending entity of the network has a corresponding sending zone, the radius of which is a function of the transmitting power of that entity.
Numerous communication protocols, with little regard for energy saving, allow for the transmitting power of any sending entity to be set in all cases to its maximum value.
While such protocols generally provide network connectivity, they do, however, involve a high energy consumption, which is detrimental to the autonomy of each entity of the network.
In the interests of energy saving, for the purpose of increasing the autonomy of the entities, it is therefore desirable to reduce the transmitting power of the network entities as much as possible while maintaining the connectivity of the network.
There are communication protocols that propose to modulate the transmitting power of a given entity according to the topology of its vicinity (see, for example, the International Patent Application published under the number WO 02/03567).
However, the protocol employed is relatively complicated and requires memories and complex algorithms which put a strain on the costs and hamper the operation of the network.
The invention seeks in particular to resolve the abovementioned drawbacks by proposing, among other subjects, a method of adjusting the transmitting power of a sending entity in a wireless communication network enabling the energy consumption within the network to be limited simply and effectively, while ensuring the connectivity of the network.

Method for adjusting a transmitting power in a wireless communications network


The addition of zinc borate alone or together with a hindered amine light stabilizer and ultra-violet light absorber to organic materials such as thermoplastic polyolefin resin, as is common in wood-plastic composites, provides a substantial reduction in the ultra-violet light degradation of the resin in comparison with similar materials made without zinc borate. This could provide substantial improvements in the long term durability of wood-plastic composites and other organic materials which are used in exterior environments and subject to ultra-violet exposure from the sun.

Organic materials exposed to ultraviolet (UV) light undergo degradation, which may change their chemical composition and structure, mechanical properties, surface appearance, and color. This UV aging is associated with natural weathering of plastics, coatings, adhesives, waxes and other special materials exposed to exterior and some interior conditions. Natural and synthetic dyes lose their color and undergo fading when exposed to short wavelength light as well. Natural weathering of materials is a complex process where UV light interaction with matter plays a significant role but may not be the only factor. There are other factors associated with aging of materials containing organic compounds, for example heat or exposure to acidic conditions in the form of acid rain or air contaminants such as sulfur dioxide, etc.

Performance enhancement in the stabilization of organic materials


An optical reading apparatus for optically reading information of a symbol on an article is comprised of a bar code reading circuit for emitting laser beams to a bar code printed on a commodity passing in front of the bar code reading circuit and for reading the information of the bar code from the laser beams reflected at the bar code. In the optical reading apparatus the bar code reading circuit includes a plurality of bar code readers which are put toward a path through which the commodity is moved so that read areas formed by the bar code readers contain the article moving path at different angles. A priority decision circuit is provided for applying a selective operation to the data read by the bar code readers.

1. Field of the Invention
The present invention relates to an optical reading apparatus for optically reading various types of information attached to an article.
2. Description of the Related Art
With recent trend of store automation, optical readers for optically reading the data expressed in bar codes printed on commodities have been installed particularly in many big stores, such as supermarkets and chain stores. The optical readers are used in combination with cash registers and POS (point of sales) terminals. The commodity data read by the optical readers are fed to the related cash register and/or POS terminals for the purpose of necessary data processing and storage. When using the optical reader, an operator or cashier picks up one of the commodities contained in a basket, checks a bar code printed area of the picked up commodity and puts the area toward a scanner window of the optical reader, and moves the commodity so faced in front of and across the window.
A bar code printed on the moving commodity is scanned with a laser beam emitted from a laser tube contained in the optical reader and applied through the single window. The laser beam reflected from the bar code is used for reading the bar code expressed data of commodity. A range within which the bar code reader can read the bar code (referred to as a read range) is defined by the size of the window, and additionally an angle of emitting the laser beam, scanning pattern, and an intensity of the reflected light.
Because of presence of those factors limiting the read range, one time read motion by the operator frequently fails to read the bar code. To reduce such failures of bar code reading, the operator checks the bar code printed location on the commodity and turns the location toward the window, and moves the commodity across the window while keeping the bar code printed location faced to the window. Such a bar code reading process physically and mentally strains the operator.


A system and method for last known good (LKG) for patches. A file cache is created to store binaries which have shipped as part of a previous wide public release—security fixes (GDRs) and service packs. There are two levels of cache, including an SP cache which keeps all of the files which were shipped as part of the service pack, and a GDR cache which keeps all of the files shipped in the GDRs. Customers do not need to download all of the binaries contained in a package when they already have the version of the dependent binaries on their system when they get the new patch. Customers only need to test the binaries which have changed, rather than everything in the new package, which speeds up the deployment of critical patches.

Software patches typically contain more than one binary in them, and in many cases only a smaller set of the binaries contained in the package actually need to be new. Other binaries (called dependent binaries from here on) are carried along because they are required for the changed binaries to function properly. When a new fix (patch) needs to be released, the latest version of all the binaries is typically included in the patch whether they need to be new or not. Testing of such patches can take several weeks to complete.
While these systems are effective for distributing patches, they include a number of disadvantages. First of all, the time to release the patches is relatively lengthy. There are also quality risks due to carrying more changes than are actually required. There is also an extra download cost for the customers in the inclusion of the additional information that is not actually needed. Furthermore, additional costs are incurred in that many corporate customers tend to test the patches in a test environment before they deploy them on their production servers. If more changes are shipped than necessary, the customers are required to do more testing than is actually needed.
The embodiment of the present invention is directed to providing a system and method that overcome the foregoing and other disadvantages. More specifically, the present invention is directed to a system and method that uses a last known good method for patches.

System and method for producing software patches


A carrier for a work box or tub includes a support ring made from opposed connected braces with telescopic handle attached at one end and wheels attached at the opposite end of the support ring.

This invention relates to a device for supporting and transporting a storage box such as a tool box or the like.
Heretofore, storage boxes or tool boxes have been developed for the home workshop. U.S. Pat. No. 5,518,139 for a Portable Storage Assembly depicts a typical storage or tool box of the type referenced. U.S. Pat. No. 5,518,139 is incorporated herewith by reference.
Movement of such a tool box or storage box from place to place is often a challenging effort because of the weight of the items contained within the box and the bulk of the box itself. Thus there is developed a need to provide some mechanism by which such a tool box may be easily transported or moved from place to place while at the same time not intruding with the operation of the box or its capability of being stored conveniently.


A method for designing a scan path to connect flip-flops in a logic circuit. Test patterns are created by the circuit designer. The circuit and test patterns are then simulated to determine potential faults in the circuit which are not detected by the patterns and not observable at any flip-flop in the circuit. The number of such faults is then reduced. For example, the test patterns can be modified and/or redundant circuit elements can be removed. A subset of flip-flops where undetectable faults are observable are then identified and connected in a scan path. Scan times can also be selected. The method may be extended to include the actual testing of the logic circuit.

The testing of a logic circuit generally includes two related tests: a functional test and a fault test. The functional test involves the application of various test patterns to the primary inputs of the circuit and a monitoring of the output signals. The output signals are compared to expected values to verify logic levels and timing The fault test determines whether the circuit contains fabrication errors. The fault test is usually designed to detect as many faults as possible in a particular "fault model". Often, the "single stuck-at" fault model is used, where each fault corresponds to an input or output of a logic gate or other element in the circuit becoming fixed at a particular logic state.
As the functional test and fault test are related, they are sometimes combined If there is a fault in the circuit, it is possible that it will show up during the functional test. "Fault coverage" is a phrase which is commonly used to express how many or what percentage of potential faults in a given fault model would be detected during a test. As the complexity of circuits increases there is often a decrease in the fault coverage of the functional test. The reason that fault coverage is less than 100% is that many potential fault sites in a complex circuit are relatively inaccessible. In other words, a long sequence of test patterns may be required to propagate or reveal the fault at a primary circuit output. As the number of inaccessible fault sites increases, the time required to develop test patterns and to test the circuit becomes excessive.
Another approach to fault testing is the use of a scan path. A scan path is a serial connection of various sequential elements (flip-flops, latches, etc.) in the circuit The scan path normally has its own input and output pins The scan path elements are modified during the circuit design so that logical values (scan patterns) may be serially shifted into and out of the elements This allows the elements to be preloaded with selected logic values and their contents to be removed and examined during testing
If a scan path connects all of the sequential elements in a circuit it is referred to as "full scan." Full scan provides good fault coverage but requires a correspondingly high amount of chip space to accommodate the scan path. If the scan path connects only some of the sequential elements in the circuit it is referred to as "partial scan." Partial scan requires less chip space but obviously allows direct access to fewer sequential elements.
Critical issues for the testing of logic circuits are the design of test patterns for the functional test and the design of the scan path and scan patterns. Typically, the circuit designer first develops test patterns for functional testing The test patterns and circuit design are then provided to an automatic fault simulator. The fault simulator determines which faults in the fault model are not detected by the functional test. The fault simulator achieves this by simulating each fault while applying the test patterns Faults which are not detected are identified in a list of undetected faults.
In order to obtain greater fault coverage, a fault test is often used in addition to the functional test. This test can be written by the circuit designer, a test expert, or can be generated by an automatic test pattern generator. The test pattern generator, a software program, automatically generates sequences of additional test patterns to reduce the number of undetected faults. The problem with this approach is that the automatically generated test patterns sequences are frequently long and often only detect a single fault. To reach a desired level of fault coverage, an excessive number of test patterns may be required. An additional problem with automatic test pattern generators is that they may require the circuit designer to have extensive knowledge of their operation. Finally, even when operated by a knowledgeable user, the test pattern generator may not be capable of achieving the desired fault coverage in a reasonable amount of time.
If a scan path is to be employed, some automatic test pattern generators also provide guidance on which sequential elements in the circuit to combine in a scan path. For both partial and full scan paths, such test pattern generators provide test patterns and patterns for the scan path. However, even with the use of scan paths, test pattern generation often results in long sequences of test patterns which can greatly increase the testing time for a circuit.

Method for designing a scan path for a logic circuit and testing of the same


A drill rod assembly including inner and outer drill rods. The drill rod assembly further including flow passages that are in fluid communication with an annular fluid flow path defined between the inner and outer drill rods. The passages preventing blockage of a drill string fluid flow path when a number of drill rod assemblies are interconnected to form a drill string.

Drill strings are typically constructed of short, individual sections of drill pipes or rods. The drill rods attach to one another to form a drill string, which can extend significant distances in some drilling applications. The drill rods used in small to medium sized horizontal drilling machines are typically either ten feet or fifteen feet in length. A drill string often extends over one hundred to three hundred feet in length. Thus, it is not unusual for a drill string to be assembled using 10 to 30 sections of drill rods, or more.
Referring now to FIG. 1, one known drill rod assembly 10 used in conventional drilling systems is illustrated. The drill rod assembly 10 includes an outer tubular drill rod 30 having external threads on one end and internal threads on the opposite end. The drill rod assembly 10 further includes a smaller, inner drill rod 20. The inner drill rod 20 fits inside the tubular outer rod 30. As previously described, typical drill rods are either ten feet or fifteen feet in length. Drill rod assemblies having inner and outer rods, however, are uncharacteristically short, to address stack-up problems described in greater detail hereinafter. The illustrated drill rod assembly 10 is only three feet in length.
Drill rods are typically positioned in the drilling machine, with one end higher than the other; thus, the illustrated assembly 10 has an up-hill end 36 and a down-hill end 38, as shown. The inner drill rod 20 includes a hexagonal first end 29 and a hexagonal second end 27. A coupling 22 is affixed to the first end 29 by a cross pin 26 that passes through a hole 25 formed in the inner drill rod 20. The cross pin 26 has an interference fit such that the pin 26 remains fixed within the hole 25 of the inner drill rod 20 when properly installed. The cross pin 26 also passes through a slotted hole 23 formed in the coupling 22. The coupling 22 has a larger diameter D1 than that of an inner diameter ID1 of the outer drill rod 30 at the up-hill end 36 of the assembly 10. The larger outer diameter OD1 of the coupling 22 prevents the inner drill rod 20 from sliding through the outer drill rod 30. The inner drill rod 20 also includes an enlarged portion 28 located adjacent to the down-hill end 38 of the assembly 10. The enlarged portion 28 prevents the inner drill rod 20 from sliding through the outer drill rod 30 in an opposite direction.
The drill rod assembly 10 is constructed by installing the inner drill rod 20 into the outer drill rod 30 at the down-hill end 38 of the assembly 10. In particular, the inner drill rod 20 is installed within the outer drill rod 20 until the expanded portion 28 of the inner drill rod 10 contacts the outer drill rod 30, and limits longitudinal movement; or until the hole 25 of the inner drill rod 20 aligns with the slotted hole 23 of the coupling 22, so that the cross pin 26 can be inserted. The coupling 22 includes an internal hexagonal bore that mates with the hexagonal first end 27 of the inner drill rod to fix the coupling and inner drill rod rotationally. The mating hexagonal bore and the hexagonal first end 29 of the coupling and inner drill rod transmit torque, while the cross pin 26 simply holds the coupling 22 and the rod 20 in place.
When assembled, the inner drill rod assembly 20 freely moves in a longitudinal direction from the position illustrated in FIG. 1 to a position where the enlarged portion 28 of the inner drill rod 20 contacts the outer drill rod 30. That is, the inner drill rod 20 slides longitudinally between an up-hill position and a down-hill position. In the up-hill position, a gap is formed between the coupling 22 and the outer drill rod 30 at the up-hill end 36 of the assembly 10. In the down-hill position, the coupling 22 is flush with the outer drill rod 30 at the up-hill end 36 of the assembly.
FIG. 2 illustrates the drill rod assembly 10 coupled to a boring tool 40. The boring tool 40 is connected to the down-hill end 38 of the assembly 10. The boring tool 40 includes an outer casing 45 having an external threaded end 44. The boring tool 40 also includes an inner rod 42 and an attached coupling 43 having an internal hexagonal bore. Unlike the drill rod assembly 10, however, the inner rod 42 of the boring tool 40 is coupled to the outer casing 45 in a fixed position. That is, the inner rod 42 of the boring tool 40 does not longitudinally slide relative to the outer casing 45. Accordingly, when the drill rod assembly 10 is coupled to the boring tool 40, the fixed position of the inner rod 42 of the boring tool 40 determines the position of the inner drill rod 20 of the drill rod assembly 10 relative to the outer drill rod 30.
More specifically, when the drill rod assembly 10 is threaded onto the boring tool 40, the coupling 43 of the inner rod 42 engages with the second hexagonal end 27 of inner drill rod 20. The inner drill rod 20 is normally positioned as shown in FIG. 1 by gravity; i.e., positioned such that the coupling 22 is flush with the outer drill rod 30 at the up-hill end 36 of the assembly 10. As the assembly 10 threads onto the boring tool 40, the inner drill rod 20 of the assembly 10 is pushed or slides longitudinally toward the up-hill end 36 of the assembly. The inner drill rod 20 slides such that an axial gap 100 is created between the coupling 22 and the outer drill rod 30, as depicted in FIG. 2. In operation, the axial gap 100 serves as a fluid flow path that allows fluid to enter the drill rod assembly 10 and pass through an annular area between the inner and outer drill rods 20, 30. From the annular area of the assembly 10, the fluid passes through to the boring tool 40 to cool the boring tool and assist in the transportation of cuttings.
FIG. 3 illustrates first and second drill rod assemblies 10a and 10b connected to form a drill string. The same boring tool 40 is coupled to the down-hill end of the drill string (i.e., the down-hill end of the lowermost drill rod assembly 10a). The first drill rod assembly 10a is connected to the second drill rod assembly 10b by threading an externally threaded up-hill end 32a of the first outer drill rod 30a into an internally threaded down-hill end 34b of the second outer drill rod 30b. As the outer drill rods 30a, 30b are being coupled, the coupling 22a of the first inner drill rod 20a engages the hexagonal end 27b of the second inner drill rod 20b.
The drill string defines a fluid flow path that extends along the lengths of the drill rod assemblies 10a, 10b. In operation, fluid is pumped into the upper most drill rod assembly, through the fluid flow path, and into the boring tool for cooling and transporting cuttings. For example, referring specifically to FIG. 3, fluid is pumped into the annular area between the inner and outer drill rods 20b, 30b of the second drill rod assembly 10b, through the gap 100 of the first drill rod assembly 10a, then through the annular area between the inner and outer drill rods 20a, 30a of the first drill rod assembly 10a, and into the boring tool 40.
As previously described, the fixed position of the inner rod 42 of the boring tool 40 determines the position of the inner rod 20a of the first drill rod assembly 10a. That is, the position of the inner drill rod 20a becomes fixed relative to the outer drill rod 30a when attached to the boring tool 40. The now fixed positions of the first inner and outer drill rods 20a, 30a of the first drill rod assembly 10a accordingly determine the position of the second inner drill rod 20b relative to the second outer drill rod 30b of the second drill rod assembly 10b. As the second assembly 10b threads onto the first assembly 10a, the second inner drill rod 20b is pushed or slides longitudinally such that an axial gap 102 is created between the coupling 22b and the second outer drill rod 30b, as depicted in FIG. 3. Fluid now enters the drill string at the axial gap 102 of the second drill rod assembly 10b, passes through to the first drill rod assembly 10a, and further passes through to the boring tool 40 to cool the boring tool and assist in the transportation of cuttings.
The inner and outer drill rods 20, 30 of each of the drill rod assemblies 10a, 10b have unavoidable variations in length resulting from manufacturing tolerances. Because of the length variations, drill rod assemblies are designed such that the overall length of interconnected inner drill rods 20a, 20b is never longer than the overall length of interconnected outer drill rods 30a, 30b. If the interconnected inner drill rods were longer than the outer drill rods, the inner rods would collide while the outer drill rods were being threaded together, causing damage to one or both of the inner and outer drill rods. Accordingly, by design, the length of interconnected inner drill rods is slightly less than the length of interconnected outer drill rods. This design requirement, however, results in a situation where the second axial gap (e.g., 102) of an up-hill drill rod assembly (e.g., 10b) is less than the first axial gap (e.g., 100) of a down-hill drill rod assembly (e.g., 10a).
FIG. 4 illustrates a drill string with a boring tool 40 and four drill rod assemblies 10a, 10b, 10c, and 10d. The difference in the overall lengths of the interconnected inner and outer drill rods, and the manufacturing variations of the drill rods, are depicted in an exaggerated manner to better illustrate the effect of this design limitation.
FIG. 4a illustrates the first axial gap 100 defined by the position of the first coupling 22a relative to the outer drill rod 30a of the first drill rod assembly 10a. When the second drill rod assembly 10b is coupled to the first assembly 10a, the first end 29a of the first inner drill rod 20a contacts the second end 27b of the second inner drill rod 20b of the second assembly 10b, and determines the relative positions of the second inner and outer drill rods 20b, 30b.
FIG. 4b illustrates the second axial gap 102 defined by the position of the second coupling 22b relative to the outer drill rod 30b of the second drill rod assembly 10b. The axial gap 102 is smaller than the first axial gap 100. When the third drill rod assembly 10c is coupled to the second assembly 10b, the first end 29b of the second inner drill rod 20b contacts the second end 27c of the third inner drill rod 10c of the third assembly 10c, and determines the relative positions of the third inner and outer drill rods 20c, 30c.
FIG. 4c illustrates the position of the coupling 22c of the third drill rod assembly 10c relative to the third outer drill rod 30c. There is no gap (shown at arrow 104). Instead, the coupling 22c is seated against the up-hill end 32c of the third outer drill rod 30c. When the fourth drill rod assembly 10d is coupled to the third assembly 10c, the first end 29c of the third inner drill rod 20c is spaced apart from the second end 27d of the fourth inner drill rod 20d. The space between these ends 29c, 27d of the inner drill rods 20c, 20d is caused by the fact that the coupler 22d (FIG. 4d) of the fourth assembly 10d has contacted the uphill end 32d of the outer drill rod 30d; thereby positioning the fourth inner drill rod 20d relative to the outer drill rod 30d. That is, the inner drill rod 20d can no longer shift or slide down longitudinally toward the down-hill end of the assembly, but is instead stopped by contact between the coupling 22d and the outer drill rod 30d.
Because of the design requirement that the inner rods always be shorter than the outer rods, any drill rod assemblies subsequently added to the fourth drill rod assembly 10d will have inner and outer drill rods similarly positioned as shown in FIG. 4d. That is, the couplings 22 of subsequently added drill rod assemblies 10 will be in contact with the outer drill rods 30, such that no gaps exist in the drill string. This results in a blockage of the fluid flow path of the drill string. Such blockages are a known problem in the industry.
In view of the foregoing, there exists a need for a drill rod assembly, having inner and outer coaxial drill rods, that minimizes and/or eliminates restricted fluid flow paths upon assembly into a drill string.

Dual rod drill pipe with improved flow path method and apparatus


A configurable semi-conductor integrated circuit has an area thereof formed with a plurality of logic circuits at discrete sites or cells respectively defining a matrix array of cells. The matrix array of cells is subdivided at least into zones, each having a matrix array of cells, and further includes a porting arrangement for each zone; and a hierarchical routing resource structure including: (i) global connection paths having selectable connections with the porting arrangement of each zone and which extend continuously across more than one zone, (ii) medium connection paths extending from the porting arrangement and selectably connectable with at least some of the cells in a zone, and (iii) local direct connection paths having for each cell a restricted signal translation system between inputs and outputs of the cells and defining first and second sets of logic circuits.

The present invention relates to semi-conductor integrated circuits of the type comprising configurable logic circuit arrays.
The invention is a development of the configurable logic circuit arrays disclosed in our British Patent Specification No. 2180382 (having a corresponding U.S. Pat. No. 4,935,734) and U.S. Pat. No. 5,001,368. In the former, the logic circuit array comprises a matrix of discrete sites or cells at each of which is a logic circuit which is adapted to perform a simple logic function. Typically the simple logic function is implemented by means of a two input NAND gate. As made each logic circuit has what may be referred to as a restricted signal translation system by which each logic circuit has selectable direct connection paths to only a few of the other logic circuits. More particularly each direct connection path which is selectable as to its conduction state, extends, for each said logic circuit, from its output to inputs of a first set of some of other said logic circuits and from its inputs to outputs of a second set of some of other said logic circuits, all of the sets (for all of the logic circuits) each being unique. Such a restricted signal translation system provides what can be conveniently referred to as local direct connection paths.
An array of this type is capable of being programmed in such a manner as to configure the various NAND gates, as required, to perform various and different logic functions. One such function is known as a latching function and in the logic array as disclosed in Specification No. 2180382, a latching function may be implemented using four NAND gates. This has the disadvantage that the greater the number of latching functions that may be required from any logic array, the fewer NAND gates remain for other required functions. This has the effect of reducing the overall effectiveness of the array.
The invention of U.S. Pat. No. 5,001,368 overcomes this disadvantage by providing an additional logic circuit for inclusion in each of the logic circuits at each discrete site to enable each site to have a greater programmable facility and thereby increase the overall utilisation of the array. As with GB 2180382 the site/cell of each logic circuit has the aforesaid restricted signal translation system. Each additional logic circuit is arranged within the logic circuit of the site or cell to be selectively controlled by control means to cause each logic circuit and additional logic circuit comprising each cell to operate as either a first or a second different simple logic function. More particularly, each cell is constructed to operate as a NAND gate or as a latch circuit function.
Providing such local direct connection paths between physically neighbouring logic circuit sites facilitates the establishment of a desired particular circuit function in a localised configuration of logic circuits, ie. in part only of the chip area occupied by an appropriate number of discrete sites of the logic circuits and by the direct connection paths. Interconnections between such localised configurations for overall circuit/system requirements can be either simply by said direct connection paths or by a further signal translation system by way of a direct connection bus directly connected to the logic circuits and extending throughout the array--for example as a series of rows and columns. Such connections might conveniently be referred to as global connections.
The so-called local direct connections and global connections constitute routing resources which are used to connect to discretely programmed logic functions. These resources can be combined by routing through a cell in order to complete the connection between functions. Once a logic circuit has been used in this matter to complete the routing that logic circuit can no longer be used for function. This reduces the overall effectiveness of the array. An object of one aspect of this invention is to overcome this disadvantage by providing additional connection resources in an arrangement not previously contemplated.
A feature of the afore-described configurable logic arrays is that each discrete site or cell is identical thus in the case of GB 2180382 each discrete site comprises a NAND gate whilst in the case of U.S. Pat. No. 5,001,368 each discrete cell comprises a NAND gate and an additional logic circuit which enables the cell to function exclusive as a NAND gate or exclusively as a latch circuit function Implementing other circuit functions (be they logic functions or otherwise) requires the various cells to be configured as required to perform various and different circuit functions Other functions frequently required are XOR and D-flip-flop. Again this has the disadvantage that the greater number of these functions that may be required from any logic array the fewer gates remain for other required functions which has the effect of reducing the overall effectiveness of the array

Programmable logic array with a hierarchical routing resource


A composition containing a magnesium component, a titanium component, a halide and a 1,2-dialkoxybenzene, wherein at least one alkoxy group has at least two carbon atoms, and the manufacture of the composition are taught by the present invention. The compositions are useful as Ziegler-Natta catalysts in the production of olefin polymers.

To polymerize olefins Ziegler-Natta catalysts are used. These catalysts contain a procatalyst made from an internal electron donor, a titanium source, a magnesium source and a halogenating agent (which may be combined with one of the other components). The use of Ziegler-Natta catalysts is known where this procatalyst is combined with a cocatalyst and commonly with an external electron donor, or more commonly called an external selectivity control agent ("SCA"). See, e.g., U.S. Pat. No. 5,093,415 to Brady et al.
One class of electron donors taught by the art is veratrole (1,2-dimethoxybenzene) and certain derivatives thereof which incorporate additional substituents on the benzene ring, U.S. Pat. No. 4,971,936 to Wilson et al. See also U.S. Pat. No. 4,107,413 to Giannini et al. However, these specific compounds have certain deficiencies in that catalysts made with them have low catalytic activity (<20 kg polymer/g procatalyst per hour) and produce polymers of low crystallinity (e.g., isotactic polypropylene with a xylene soluble of greater than 30% wt and a L.sub.(iso) (.sup.13 C NMR) of less than 50 even with a SCA). The use of these electron donor compounds solely to produce polymers of low crystallinity is confirmed in Japanese patent application Nos. 2613169 and H1-307519. It is desirable to find electron donors which result in catalysts of improved activity and selectivity.

Union Carbide Chemicals & Plastics Technology Corporation