A gel mixing system that employs a dynamic diffuser for quickly removing the air from the fluid as the fluid exits a traditional gel mixer and employs progressive dilution of the gel in a series of hydration tanks to maximize hydration time without allowing the gel to become so viscous that it is not easily diluted or pumped. High shear agitation of the fluid between the hydration tanks helps to increase the hydration rate. Progressive dilution of the gel increases residence time of the gel in the tanks and results in longer hydration time in the limited tank space available, resulting in continuous production of gel that is almost fully hydrated when it is pumped to the fracturing blender and subsequently to the well bore without the need for an increase in the volume of the hydration tanks.

1. Field of the Invention
The present invention relates to a system for continuously mixing gel fluid that will be used to transport fracturing proppant into a well formation to prop open the formation after fracturing. The system employs a dynamic diffuser to remove air from the fluid as the fluid leaves the dynamic diffuser and travels through a series of hydration tanks. High shear agitation is used to help mix the gel fluid and dilution fluid as it moves through the hydration tanks. This system allows increased hydration time and more complete hydration of the gel fluid in the limited tank space of skid, truck, or trailer mounted portable equipment than is possible with current gel mixing systems.
2. Description of the Related Art
Currently when mixing guar powder and water to form a liquid gel for use to transport fracturing proppant into a well formation, the mixing is done by a portable mixer and one or more portable hydration tanks. All of the equipment necessary to mix the gel is skid, truck, or trailer mounted so that it can be transported to the well site. There at the well site, the gel is constantly mixed, transferred to the fracturing blender, and pumped into the well bore. Because the equipment is truck or trailer mounted, the tank volume available for allowing the gel to hydrate after it is mixed with water is limited.
One of the problems with current gel mixing systems is that, without the use of large hydration tanks, the gel is not fully hydrated to the desired viscosity before the gel is transferred to the fracturing blender. Large hydration tanks can not be readily skid, truck or trailer mounted for use at a well site. Without using large hydration tanks, the gel will have a short residence time of the liquid within the smaller skid, truck or trailer mounted hydration tanks which does not allow sufficient time for the gel to become adequately hydrated before it is transferred to the fracturing blender prior to being used in the well.
The present invention addresses these problems by creating a gel concentrate, employing a dynamic diffuser for quickly removing the air from the fluid as the fluid exits the gel mixer, and by progressively diluting the gel concentrate in a series of hydration tanks to maximize hydration time without allowing the gel to become so viscous that it is not easily diluted or pumped. High shear agitation of the fluid between the hydration tanks also helps to increase the hydration rate. By progressively diluting the gel concentrate, residence time and hydration time are maximized in the limited tank space. The result of this new continuous gel mixing system is that the gel is almost fully hydrated when it is transferred to the fracturing blender without the need for an increase in the volume of the hydration tanks.
Some gels hydrate faster than others. This system is useful for both standard gels and fast hydrating gels. With fast hydrating gels, the system can be operated at a higher throughput rate, thus extending the usefulness of the system.
One object of the present invention is to provide a system that continuously mixes guar powder with water to produce a gel.
A further object to the invention is to provide a system that employs high sheer pumps that allow the guar to hydrate into a viscous gel more quickly than prior art systems. When dry guar powder is mixed with water, a thick gelatinous coating is formed around each of the particles of the dry powder as the powder begins to hydrate at its surface. These partially hydrated particles may be called micelles. They are relatively dry in their nucleus and are progressively more fully hydrated at their surface. The high sheer pumps used in the present system tend to disrupt or sheer this gelatinous outer coating off of the micelles. This allows the dryer inner portions and nucleus of the micelles to be contacted with water more quickly, thereby speeding up the hydration process.
Another object of the invention is to increase the hydration time of the gel within the limited hydration tank space.
Still a further object of the invention is to provide a system that does not require special chemicals such as non-aqueous carrying fluids, suspending agents, and dispersing agents for the process. By not requiring special chemicals, some of which are considered harmful to the environment, the end gel product is more economical and more environmentally friendly.
A final object of the present invention is to employ mobile equipment such that the equipment would be truck or trailer mounted and the gel would be produced at or near the well site using the truck or trailer mounted equipment.


A semiconductor device includes a first buffer suitable for receiving and buffering data, a second buffer suitable for receiving and buffering a data strobe signal, a strobe line suitable for transferring the data strobe signal; a plurality of data transfer lines suitable for transferring data inputted at corresponding turns among data inputted in series through the first buffer, a latch signal generation block suitable for generating a plurality of latch signals which are sequentially activated, based on the data strobe signal transferred through the strobe line, a data latch block suitable for latching and aligning in parallel the data inputted in series through the first buffer, based on the latch signals, and a data transfer block suitable for transferring the data latched by the data latch block to the plurality of data transfer lines, according to a correspondence relationship determined based on an input start signal that is activated at a time when the input of data corresponding to the data input command is started.

1. Field
Various embodiments of the present invention relate to a semiconductor device.
2. Description of the Related Art
A semiconductor memory device receives a data strobe signal together with data transferred from a memory controller. The data strobe signal is an echo signal for synchronizing the semiconductor memory device and the memory controller when the data is transferred there between, and ensures stable transmission of the data. After the semiconductor memory device has received the data, the semiconductor memory device aligns in parallel the data, which have been transmitted in series, and transfers and stores the aligned data to and in an internal circuit, for example, a cell array.
The internal circuit operates in synchronization with a clock signal, which is applied together with a command and an address from the memory controller. Since the clock signal and the data strobe signal are inputted to the semiconductor memory device through different paths, a phase difference between the clock signal and the data strobe signal may occur. Therefore, to process the inputted data in the semiconductor memory device, the data, which is inputted in synchronization with the data strobe signal, and the clock signal should be synchronized with each other.


A photosensitive resin composition includes: an acrylic copolymer comprising a polymerization product of a first monomer comprising at least one selected from an unsaturated carboxylic acid and an unsaturated carboxylic acid anhydride, and a second monomer comprising an olefin-based unsaturated compound; a photosensitive component comprising at least one 1,2-quinonediazide-5-sulfonic acid ester compound selected from compounds represented by Chemical Formulae 1 to 4; a coupling agent; and a solvent, wherein a total amount of asymmetric compounds in the photosensitive component is greater than or equal to 45 area percent as determined by high performance liquid chromatography:

(a) Field
The present application relates to a photosensitive resin composition and a pattern forming method using the same.
(b) Description of the Related Art
In general, a flat panel display, which is widely used presently, includes various types, for example, a liquid crystal display ("LCD") and an organic light emitting diode ("OLED") display.
In a process of forming the flat panel display, a photoresist material may be used for patterning a film via a photoprocess. Also, the photoresist material may be directly formed into the film through exposure and developing.
An insulating layer, a column spacer, an overcoat layer, and a color filter layer may be formed by using the photoresist material as well. Resolution, adherence, and remainder rate may be influenced according to components of a photosensitive resin composition used to form the photoresist material.

Photosensitive resin composition and method of forming pattern using the same

Abstract: wherein R1 is a hydroxyl group or a methyl group, and NQD is a 1,2-quinonediazide 5-sulfonyl group.


The invention provides a driving calibration apparatus of an electrostatic MEMS scanning mirror and a driving calibration method thereof The driving calibration method includes the following steps. Different reference voltages are sequentially set to drive a plane mirror of the electrostatic MEMS scanning mirror to swing. Projection positions on a projected surface corresponding to the reference voltages that the laser beam projects to are determined. A driving lookup table is established according to the reference voltages and the corresponding projection positions. Calibrated driving voltages corresponding to ideal projection positions are determined according to the driving lookup table. The pane mirror is driven to swing according to the calibrated driving voltages.

1. Field of the Invention
The invention is directed to a driving calibration apparatus and a driving calibration method thereof. More particularly, the invention is directed to an apparatus for calibrating driving voltages of an electrostatic MEMS scanning mirror and a driving calibration method thereof
2. Description of Related Art
An MEMS scanning mirror is an important device for transmitting optical signals and is widely applied to optical-electro-mechanical system integrated products and techniques, such as projectors, barcode readers, optical modulators, optical choppers, optical switches, optical positioning, and so forth. The MEMS scanning mirror is composed of an actuator and a plane mirror, the actuator is in charge of applying a force on the plane mirror to enable the plane mirror to generate angular displacement so as to reflect an incident optical signal, and a transmission direction of the optical signal is determined according to the angular displacement of the plane mirror. Methods for driving the MEMS scanning mirror are typically classified into an electrostatic, an electromagnetic, a thermo and a piezoelectric methods. Among them, the electrostatic MEMS scanning mirror has advantages, such as greater driving force and better compliance in semiconductor manufacturing processes and thus, have high potential.
When being applied in biaxial scanning, the electrostatic MEMS scanning mirror controls swing angles by means of controlling DC voltages. Since the swing angles of the electrostatic MEMS scanning mirror is not linearly relative to the DC voltages, difficulties occur in controlling the swing angles of the electrostatic MEMS scanning mirror, and as a result, the electrostatic MEMS scanning mirror probably incurs an issue of non-uniform scanning intervals. More specifically, when being applied in image projection, the issue of non-uniform scanning intervals probably incurs an issue of non-uniform brightness of images projected by the electrostatic MEMS scanning mirror.

Driving calibration apparatus of electrostatic MEMS scanning mirror and driving calibration method thereof


The present invention relates to a photon scanning apparatus comprising a photon source (2) to emit a photon beam (4), a photon detector (6) to detect photons emitted from the photon source (2). The photon source (2) is adapted to emit the photon beam (4) in accordance with a predetermined pulse width modulation scheme at a predetermined flux rate, wherein the pulse width modulation scheme defines pulse widths of the photon beam (4) for respective positions of the photon source (2) and the photon detector around a central axis (R) and an object to be scanned. The photon detector (6) is adapted to start detecting photons with a delay relative to the photon source starting to emit photons and to finish detecting photons prior to the photon source stopping to emit photons. The photon scanning apparatus thus only has to be calibrated for the predetermined flux rate.

A conventional CT scanner includes an X-ray tube mounted on a rotatable gantry opposite a detector array located across an examination region. The rotatable gantry, and hence the X-ray tube, rotates around the examination region. The X-ray tube is configured to emit X-ray radiation. A radiation intensity profile shaper such as the well-known "bow-tie" filter attenuates the emitted X-ray radiation directed towards the examination region to a greater degree at peripheral regions, relative to a more central region, thereby reducing the flux at the outer regions, which improves radiation efficiency.
A source collimator collimates the filtered X-ray radiation, producing a radiation beam in the direction of the examination region. The filtered radiation beam traverses the examination region (and an object of interest therein), and is detected by a detector array, which includes a one or two dimensional array of detector pixels. The detector pixels, in response, generate and output signals indicative of the detected radiation. The signal can be reconstructed to generate volumetric image data. Additionally, the volumetric image data can be processed to generate one or more images of the object of interest.
A spectral CT scanner has included the above-discussed elements with the addition of photon-counting detector pixels (sensor material e.g., CdTe, CdZnTe, etc.) (and, optionally multiple sources, kVp switching, etc.). Unfortunately, the bow-tie filter alters the primary beam spectrum of the X-ray source. That is, while the spectrum in front of the bow-tie filter can be considered homogenous for all angles, spectral distortions are caused by the bow-tie filter material, and the shape of the bow-tie filter results in variations in fan angle direction.
One common approach of calibrating photon counting detectors is to map a known set of absorber compositions to detector signals, which are subsequently used, e.g. in form of a look-up table, for material decomposition. This technique thus requires a calibration phantom whose complexity increases with number of absorber materials, since each material combination that may occur in measured objects has to be realized in the calibration procedure or an equivalent pair of absorbers as described in "Estimator for photon counting energy selective x-ray imaging with multibin pulse height analysis" by Alvarez, Robert E., Med. Phys. 38 (5), pages 2324-2334, May 2011.
For example, in order to acquire calibration data for medical CT, a calibration procedure has to be performed, where all combinations of all relevant thicknesses of bone, e.g., 0-10 cm, and all relevant thicknesses of soft tissue, e.g., 0-40 cm, have to be taken into account. A suitable procedure would be to produce two step phantoms of materials with similar X-ray attenuation properties as bone and soft tissue, e.g., aluminum and a polymer, respectively, and acquire data for all combinations of step numbers of both step phantoms.
In order to allow varying properties of individual pixels or the angle dependence of the X-ray spectrum, the calibration data has to be acquired for all detector pixels. For example, a step phantom comprising 10 material thicknesses each, a total of 100 individual measurements would have to be made for each pixel. With a third material, e.g., iodine or another contrast agent, a third material would have to be included, adding an additional dimension to the calibration procedure.
Another approach comprises a detector model to estimate the photon counts for each material combination. Here, the detector model needs to be calibrated using a calibration phantom with one or more materials. Regardless of the chosen approach, each detector pixel needs to be calibrated due to pixel-to-pixel variation within the detector and changes of the primary spectrum due to the bow-tie already mentioned above. Using photon counting detectors, the described calibration is necessary not only for different material combinations, but also for different combinations of X-ray tube currents and X-ray tube acceleration voltages due to the effect of pulse pile-up. Advanced CT scanners use dynamic dose modulation to adapt the X-ray flux for each projection according to the attenuation profile of a patient. One prominent example is the patient's shoulder with a strong attenuation of horizontal rays and a lower attenuation of vertical rays. The modulation aims for homogeneous noise distribution yielding improved dose utility. Dose modulation is an indispensable feature in medical imaging as it adopts the X-ray flux to the patient's anatomy. Dose modulation may be achieved by modulating the X-ray tube current. Accordingly, the working point of the detector would vary from view to view, which would require a proper calibration for all occurring working point settings of the scanner during the scan, since the detected counts are a non-linear function of the incoming photon flux.
A new technique called X-ray tube grid switching (GS) allows for ultra-fast binary (on/off) X-ray flux modulation of the X-ray tube output. With switching times below 1 μsec, the flux modulation can be used to do sparse angular sampling for CT. In addition, it enables a kind of pulse width modulation to radiate the detector only for a limited time interval within an integration period, thus allowing to expose a patient to X-ray radiation as little as necessary.
For photon counting CT scanners pulse width modulation cannot be easily applied to modulate doses. For high flux imaging, photon counting detectors will suffer from the effect of pulse pile-up. Photon counts may get lost due to the dead time of the detector or two lower energetic photons may be counted as one photon. Wherein the response curve of an ideal photon counting detector would increase linearly with an increasing flux, a real photon counting detector's response curve is non-linear. The pile up effect during operation with a stable flux thus differs from the pile up effect during rise up of the photon flux at the beginning of a pulse as well as during ramp down of the flux at the end of a pulse.
In that respect, US patent application US 2016/0324494 A1 discloses an imaging system which includes a radiation source with a focal spot that emits a beam of X-ray photons that traverses an examination region. The imaging system further includes a photon counting detector array that detects a sub-set of the X-ray photons that traverse an examination region. The imaging system further includes a controller that generates and transmits a pause signal, in response to a calculated drop in an intensity of the emitted the beam of X-ray photons below a predetermined intensity level, which causes the photon counting detector array to pause detecting the sub-set of the X-ray photons. The imaging system further includes a counter that counts, for each of a plurality of counting periods, the X-ray photons of the sub-set detected by the photon counting detector array in the corresponding counting period.
Further, US patent application US 2005/0089135 A1 discloses a system and method of diagnostic imaging is provided that includes determining a position of a subject in a scanning bay and tailoring X-ray attenuation such that the specific position of the subject is taken into consideration. In accordance with the concept disclosed therein, a proper attenuation filter configuration is automatically selected, patient centering is corrected and noise prediction errors are corrected, thereby increasing dose efficiency and tube output.

Pulse-width modulation for a photon scanning apparatus


A method of manufacturing a liquid crystal display device includes steps of preparing first and second substrates, forming alignment films on one surfaces of the first and second substrates, respectively, performing rubbing treatment on the alignment films, screen-printing a seal member on the one surface of the first substrate so as to surround a display area, and stacking the first and second substrates on each other while the first surfaces face to each other, with rubbing directions of the alignment films on the first and second substrates being parallel to each other, and joining the first and second substrates through the seal member by curing the seal member while the first and second substrates are bonded to each other through the seal member. The screen-printing is performed while a squeegee is moved in a direction parallel to the rubbing direction of the alignment film formed on the first substrate.

1. Field of the Invention
The present invention relates to a method of manufacturing a liquid crystal display device.
2. Description of the Related Art
In manufacturing a liquid crystal display device, after rubbing treatment is performed on alignment films respectively formed on the inner surfaces of a pair of substrates, a seal member for joining the pair of substrates is printed on the inner surface of one of the substrates by screen printing using a screen which masks a non-print area and a squeegee which is brought into contact with the screen and moved in a predetermined direction. In this case, during printing of the seal member, the surface of the alignment film which has undergone rubbing treatment is partially worn by the screen.
In order to solve this problem, for example, a method of manufacturing a liquid crystal display device is disclosed in Japanese Patent No. 2774714. In manufacturing a liquid crystal display device such as a TN or STN liquid crystal display device in which the liquid crystal molecules of a liquid crystal layer are twisted/aligned between a pair of substrates by performing rubbing treatment on the alignment films formed on the inner surfaces of the pair of substrates in directions crossing each other at a predetermined angle, according to this method, even if the surface of an alignment film which has undergone rubbing treatment is partially worn by the screen, the influence of this wear on the twist alignment of the liquid crystal molecules is prevented by performing screen printing of the seal member while moving the squeegee in a direction crossing the rubbing direction of the alignment film formed on the substrate on which the seal member is printed at an angle larger than 90°.
The conventional manufacturing method, in which a seal member is printed by moving the squeegee in a direction crossing the rubbing direction of an alignment film at an angle larger than 90° as described above, is effective in manufacturing a liquid crystal display device having liquid crystal molecules twisted/aligned. However, in manufacturing an untwisted/aligned liquid crystal display device in which the molecular long axes of the liquid crystal molecules of a liquid crystal layer are aligned with the rubbing directions of the alignment films respectively formed on the opposed inner surfaces of a pair of substrates by performing rubbing treatment on the alignment films in parallel directions, the difference between the rubbing direction of each alignment film and the direction in which the film is worn by the screen influences the alignment of the liquid crystal molecules to disturb the alignment of the liquid crystal molecules.

Method of manufacturing liquid crystal display device


Blower made up of at least two axially stacked, interlocking fans. Each fan is enclosed in a housing the axially opposite ends of which are flanged. Opposing flats on immediately neighboring flanges are formed with complementary twist-locking features. The twist-locking features are configured in such a way that when the fans are stacked, the opposing flats will not be in contact with each other unless the housings are twisted out of axial alignment to bring the opposing flats flush together, and such that with the opposing flats flush in contact, twisting the housings back into axial alignment locks them together.

1. Field of the Invention
This invention relates to a blower having a plurality of fans connected or engaged each other in a rotational axis direction.
2. Description of the Related Art
In order to improve a capacity of air flow and a static pressure generated by a fan without increasing its impeller's diameter, a blower called "a double fan" is widely used in which a plurality of axial fans are arranged along the rotational axis thereof.
In a conventional blower having a plurality of fan impellers, two or more impellers are encased in a single housing or each impeller is encased in each housing, and the housings are connected with each adjoining housing in rotational axis direction. Generally, a large amount of development cost is required to design a new blower including a design of its housing, therefore one way for realizing cost reduction is to connect or engage a plurality of existing axial fans or centrifugal fans in rotational axis direction, which meets a performance requested for the new blower.
There are two major ways to connect or engage two or more adjoining housings. One way is that flanges of the housings are fixedly coupled to each other by screws and the other is that elastic hooks formed on one housing are engaged with the recesses of the other housing.
In the case where the fans are fixedly connected by screws, however, special tool such as screwdriver or wrench may be required. This increases the number of steps for connecting the blowers as well as the number of parts of the blower, thereby the cost for producing the blower may increases because of its complex structure of the blower.
In connecting the adjoining fans by elastic hooks, on the other hand, since the elastic hooks can be formed at the same time as the housing is formed by a molding process, the cost for the housing with such elastic hooks may not increase. Also, the elastic hooks can be engaged very simply without increasing the number of steps for engaging.
However, when the connection by means of the elastic hooks is performed, there are two requirements contradicting each other. One requirement is for securing a sufficient elasticity caused by elastic deformation which may be required for completing the engaging step to make the two adjoining fans engage and the other requirement is for a sufficient engaging force. Specifically, in the case where the elasticity of the elastic hooks is increased to realize an easier engaging step, the engaging force decreases and the insufficient engaging force would be realized. On the other hand, in the case where the elasticity of the elastic hooks is decreased, the engaging force increases and the engaging step would not be accomplished, because the elastic hooks may be damaged or the housing may be warped.


A by-pass level indicator includes a main tube in communication with a tank via a pair of by-pass tube members, a float containing a magnet and an indicator attachably mounted to the main tube and having a series of magnetic colored flags reacting with the magnet of the float for indicating level of the tank. Each of the by-pass tube members includes a T-joint having an upright tube receivably engaging with one end of the main tube and a transverse tube integrally extending from the upright tube communicating the main tube to the tank. The transverse tube has a male threaded end portion to partly receiving an O-ring. The by-pass tube member further has a combination of a union and a collar adapted to communicating the transverse tube with the tank. The collar is threadingly engaged with the male threaded end portion of the transverse tube and clamps a connecting tube of the union to the transverse tube simultaneously compressing a protruding portion of the O-ring, thereby achieving a fluid-tight seal.

1. Field of the Invention
The present invention relates to a pair of by-pass tube members for a by-pass level indicator, each of which is configured as a T-joint receiving one end of the main tube and secured with the main tube by means such as an adhesive, thereby obtaining a strengthened engagement therebetween and facilitating manufacture of the by-pass level indicator.
2. Description of Related Art
A bypass level indicator is installed outside of a vessel or tank and includes a liquid chamber, a float containing a magnet and disposed inside the liquid chamber and a series of colored magnetic flags. The bypass level indicator enables one to efficiently measure the level of the liquid inside the tank from an outside thereof.
Referring to FIG. 4, a bypass level indicator made of polypropylene includes a main tube 80 in communication with a tank via a pair of bypass tubes 82. The main tube 80 has a top cover 86 and a bottom cover 88 respectively engaged with a top end and a bottom end thereof and a series of colored magnetic flags which form an indicator 84 attachably mounted thereto. The top cover 86 and bottom cover 88 each define threaded bore to receive a respective plug (not shown) for maintenance purposes etc. The indication method between the magnet installed in the float and the magnetic colored flags is conventional and not described in detail here. The pair of bypass tubes 82 are respectively welded on an upper portion and a lower portion of the main tube 80.
This bypass level indicator has a disadvantage that it is difficult to weld the pair of bypass tubes 82 onto the main tube 80 satisfactorily, because the bypass tube 82 and the main tube are of circular peripheries and need to be welded with each other perpendicularly.
Another conventional bypass level indicator made of PVC is shown in FIG. 5. The bypass level indicator also includes a main tube 90 in communication with a tank via a pair of bypass tubes 922. This bypass level indicator does not employ a welding process to secure the pair of bypass tubes 922 to the main tube 90. Instead, it uses a pair of T-joints 92 to engagingly connecting the pair of bypass tubes 922 with the main tube 90. The pair of T-joints 92 are receivably interposed to an upper portion and a lower portion of the main tube 90, respectively, and a pair of covers 94 are used to cover a top end and a bottom end of the main tube 90. To securely engage with the main tube 90, each of the pair of T-joints 92 defines a middle portion 920 with a diameter slightly smaller than that of the main tube 90 for restricting movement of the main tube 90. This has a disadvantage that a float 98 received in the main tube 90 may be jammed due to the smaller diameter of the T-joint 92, resulting in a reduction of effective length of the main tube 92. Furthermore, the bypass level indicator typically has a pair of flanges 96 integrally formed on the pair of bypass tubes 922 to be mounted to the tank. Therefore, not only a volume and cost resulting from packaging the bypass tubes 922 and the flanges 96 will increase, but a damage to the pair of flanges 96 during assembling and transportation may occur.
The present invention provides an improved by-pass tube member for a by-pass level indicator to mitigate and/or obviate the aforementioned problems.

By-pass tube member for a by-pass level indicator


An internal combustion engine with a supercharger comprises an internal combustion engine including a plurality of cylinders; an intake passage that supplies gas to the internal combustion engine; a turbocharger-type supercharger including a turbine portion having a plurality of exhaust gas introduction passages; and an exhaust passage including a plurality of connecting passages that connect the plurality of cylinders and the plurality of exhaust gas introduction passages, wherein exhaust gas discharged from the internal combustion engine flows through the exhaust passage. The internal combustion engine comprises a bridge passage that connects two or more of the plurality of connecting passages to each other; a branch passage connected to the bridge passage; and a first opening and closing device provided into the bridge passage to open and close the bridge passage.

Exhaust-driven turbocharger-type superchargers that perform supercharging using flow strength of an exhaust stream are frequently used as superchargers to improve the intake efficiency of an internal combustion engine. For example, see Patent Document 1. Patent Document 1 discloses an exhaust system in which two or more collecting tubes joining a plurality of exhaust passages, are connected with a bridge passage serving as a communication tube. The communication tube is adapted to be opened and closed by a valve. Patent Document 1 describes the communication tube as contributing to an improvement in thermal efficiency in an internal combustion engine. Patent Document 1 also describes that the internal diameter of the communication tube may be set to 20 to 100% of the internal diameter of each collecting tube to ensure the contribution to an improvement in thermal efficiency.    Patent Document 1: Japanese Laid-open Patent Publication No. 2001-164934

Internal combustion engine with supercharger


A device for transforming internal combustion engines using liquid fuel into over-pressurized engines using gas. Liquid fuel is fed into an annular chamber surrounding a needle. The fuel and primary air is injected at a controlled flow and pressure into a choke chamber to form an air-fuel premixture made of very fine microdrops. During the downstroke of the piston, the premixture is aspirated, causing the projection of the premixture against the blades of a rotor which rotates at high speed. The gasification chamber is then over pressurized during the closing of the intake valve and the introduction of the mixture.

1. Field of the Invention
The present invention relates to a device for the transformation of internal combustion engines using liquid fuel, into gas, over-pressurised engines.
2. Discussion of the Background
At the present time, only two types of fuel feeding devices for automobile engines are known: carburettors, generally of the float type, and sequential projection injectors. The main drawbacks arising from the projection into the cylinders of liquid fuel pulvesed into more or less fine drops, in collaboration with a certain volume of air, are essentially an incomplete internal combustion of the air-fuel mixture in the cylinders, which causes a fairly rapid soiling of the cylinders, poor yield and increased environmental pollution through the unburned particles in the air-fuel mixture. The soiling of the cylinders rapidly destroys the lubrication features of the engine lubricant because of the particles and soot generated by the unburned fuel. This provokes the premature damaging of the piston rings and skirts of the engine, and that of the crankshaft bearings and the piston rods, in the case of high pressure feeding diesel engines. Very high pressure feeding requires the use of high accuracy pumps, and thus is very expensive, as well as a feeding circuit adapted to resist such pressures. The injection system is also very accurate and expensive and easily liable to go out of adjustment.
In order to overcome such drawbacks, car manufacturers have been researching mechanical, electrical or thermal means which involve, among other features, with a pre-chamber preceding the classical distributor. However, the improvement provided to engines, more generally petrol engines, cannot be carried out on the so called diesel engines, which are provided with high pressure injection devices at 150 bar. The tendency is to further increase the accuracy of the injection, in order to feed each cylinder with exactly the same amount of fuel. This, together with the fact that the means of control are becoming more sophisticated and expensive, causes an increase in the likelihood of breakdown. They have as a drawback the fact that they easily go out of order. Generally, the know devices need continual, expensive maintenance, which is rarely warranted by the users, but is by the professionals in the art, who are equipped with the appropriate tools.
It is to be noted that the problem of automobile pollution, mainly due to heavy fuel consumption, arising from the continuous growth of world-wide automotive park, has become a main concern in all developed countries, and so it will in all the developing countries, where the automotive park is rapidly being extended.
The problems which the invention seeks to overcome are the following:
to eliminate the pollution of petrol and diesel internal combustion engines, specially the pollution generated by diesel engines in the so-called "heavy weighted" vehicles, but also in marine engines, electrical power generation engines, and so on, by removing the unburned particles, PA1 to reduce the fuel consumption by about a 20%; PA1 to markedly improve the efficiency of such engines; PA1 to increase their life span; PA1 to diminish the exploitation, maintenance and adjustment costs. PA1 a gasification chamber provided in each cylinder, directly connected to the intake of all the explosion chambers of the said engine, PA1 a means for injecting liquid fuel under a pressure of 5 to 7 bar, PA1 a means for injecting primary air under a pressure of 2 to 4 bar, PA1 a means for injecting secondary air under a pressure of some hundreds of millibar, PA1 a micro chamber for the diffusion and the making of a air-fuel pre-mixture: PA1 a means for eliminating, for mixing and for the molecular breaking-up of the air-fuel mixture, transforming it into a homogeneous gas within each of the said chambers, under a pressure of about between 100 and 400 millibar, PA1 means for electronically controlling the synchronous operation of the valve needles, of the air intake, for optimising the air-fuel mass ratio, and for controlling the pressurised liquid fuel distribution pump, PA1 an high voltage electronic ignition facility. PA1 total breaking-up at a molecular level, and transformation of the air-fuel mixture into homogeneous gas within the gasification chamber before the intake into the explosion chamber, thus resulting in the total lack of unburned gas at the engine exhaust gases outlet, and therefore a very important reduction of the air pollution owing to these gases, this pollution being almost limited to that of CO2; PA1 great simplification of the feeding of the internal combustion engines and a remarkable reduction in the costs of this function; PA1 removal of carburettors, and their inherent drawbacks, and removal of direct injection, which is day by day replacing carburettors, which increases the fuel consumption and the volume of unburned gases; PA1 significant improvement of efficiency and life span of internal combustion engines, since gases are totally burned; PA1 fuel saving of about 20% and lubricant saving, since the frequency of lubricant change is reduced to less than half; PA1 improvement of lubrication and a longer engine life span, together with cheaper maintenance; PA1 very short return period of the device over-cost, on the basis of fuel, lubricant, maintenance and engine life span savings. PA1 ease of adaptation on any existing kind of internal combustion engines and particularly for diesel engines.

Device for injecting a fuel gas mixture into a combustion engine


An outboard seal between a rack bar of a rack and pinion steering gear and a fluid motor cylinder tube around the rack bar. The outboard seal includes an annular bulkhead in an outboard end of the cylinder tube around the rack bar, a metal retaining ring preventing dislodgment of the bulkhead from the cylinder tube by fluid pressure in the cylinder tube, and a seal ring adjacent an end wall of the bulkhead having an outer surface resiliently pressing against the cylinder tube and an inner lip biased against the rack bar by garter spring. A coupling between the seal ring and the bulkhead consists of an annular groove in a cylindrical shoulder on the bulkhead and a flexible lip on the seal ring stretched over the cylindrical shoulder and seated loosely in the annular groove. The flexible lip and the annular groove cooperate in uniting the bulkhead and the seal ring for unitary handling and transport outside of the cylinder tube and in uncoupling the seal ring from the bulkhead inside the cylinder tube to isolate the seal ring from relative movement between the bulkhead and the cylinder tube which would otherwise cause the seal ring to wear.

U.S. Pat. No. 4,351,228, issued Sep. 28, 1982 and assigned to the assignee of this invention, describes a motor vehicle rack and pinion steering gear including a steering gear housing, a rack bar supported on the steering gear housing for back and forth linear translation, and a steering assist fluid motor consisting of a cylinder tube around the rack bar defining an extension of the steering gear housing, a piston on the rack bar sealing against the cylinder tube, and inboard and outboard seals between the cylinder tube and the rack bar on opposite sides of the piston. The inboard seal consists of a metal-reinforced elastomeric ring having an outer cylindrical surface interference fitted in the cylinder tube adjacent the steering gear housing and an inner lip biased against the rack bar by a garter spring and reinforced by a polymeric annular insert against being squeezed between the rack bar and the steering gear housing. The outboard seal consists of a metal annular bulkhead in an outboard end of the cylinder tube defining a bearing for the rack bar, a static O-ring in a groove in the bulkhead facing the cylinder tube, and a seal ring on the bulkhead having an annular lip engaging the rack bar. An outboard seal according to this invention is an improvement relative to the outboard seal of the rack and pinion steering gear described in the aforesaid U.S. Pat. No. 4,351,228.


Transceivers are selectively activated to reduce power in a network of data processing devices linked by a data transmission loop. Each of the devices is linked by a transceiver, and passes data from a previous device in the loop to a next device in the loop when not transmitting data onto the loop. For example, the data processing devices are disk drives in a storage subsystem. Delays in establishing communication after transceiver activation can be avoided by continuously powering a bit clock oscillator or bit synchronizer. In one embodiment, a loop controller in the loop sends activation and deactivation signals to addressed transceivers via an auxiliary channel. In another embodiment, when a device detects that communication is occurring between other devices for a certain period of time, the device selectively deactivates its transceiver for the certain period of time. For redundancy, the data processing devices can be connected via dual loops, and then power is further reduced by activating at most one of the two transceivers in a device at any given time. In this case, if a transceiver failure occurs, the failed transceiver is bypassed and the other transceiver for the device is activated. For example, when a loop controller detects a transceiver failure, the loop controller sends transceiver activation and deactivation signals over the auxiliary channel.

1. Field of the Invention
The present invention relates generally to a data network having data processing devices linked for data transmission. In particular, the present invention relates to obtaining a reduction in the power consumed by data transceivers in such a network.
2. Background Art
Data transmission loops have been used in local area networks of data processing devices for coupling data terminals to a central processor. The loop topology permits each data terminal to monitor data transmitted over the loop, and to insert data into the loop. More recently, the loop topology has been proposed for connecting disk drives to a storage controller in a storage subsystem. In this application, the loop interfaces in a simple way to optical fibers interconnecting the storage controller to the disk drives, and the number of pin connections to the disk drives is reduced for enhanced reliability. Manufacturers of data processing devices and disk drives are presently cooperating in the development of standards for the transceivers, cables and connectors to be used in connecting loops of disk drives to data processing equipment. The data transmission loop has been named Fibre Channel Arbitrated Loop, and the current standards are described in Kurt Chan, FC-AL Direct Disk Attach Profile (Private Loop) Version 1.2, Hewlett-Packard, 9000 Foothills Blvd., Roseville, Calif. 95747-5601, Preliminary Draft Version, 1.20 (Jan. 4, 1995), incorporated herein by reference. One disadvantage of the Fiber Channel Arbitrated Loop is that all of the transceivers in the loop are running continuously. To avoid skews and to minimize the number of connections, data is transmitted serially over the loop. Consequently, it is desirable to transmit data at the highest practical rate, such as at 265.625 MHz, 531.25 MHz, or preferably 1.0625 GHz. Consequently, transceivers must consume a substantial amount of power in order to serialize and deserialize the data at such a high rate. For example, a 3 and 1/2 inch disk drive employing a standard SCSI interconnect consumes about 15 watts. The 3 and 1/2 inch drive, when adapted with Fiber Channel transceivers available in the first quarter of 1996, is expected to require no less than about 18 watts. Consequently, a disk array cabinet designed for the standard SCSI drives cannot be fully populated due to power supply and cooling limitations. The option of increasing the power supply and cooling capacity is undesirable since it would require a re-design of the power supply and cabinets, and would increase the cost of ownership, cost of air conditioning, and the cost of power.

Reduction of power used by transceivers in a data transmission loop


High-purity benzyl benzoate is recovered by distilling the residue remaining after removal of unreacted toluene and benzoic acid from a reaction mixture produced by the oxidation of toluene by molecular oxygen in the presence of a metal catalyst thereby separating a fraction of benzyl benzoate containing 80 wt % or more benzyl benzoate, 10 wt % or less benzoic acid and 10 wt % or less fluorenone, and purifying the fraction of benzyl benzoate by crystallization such as recrystallization. According to this process, it is possible to recover high-purity benzyl benzoate by a simple operation at low cost from the by-product formed in the manufacture of benzoic acid.

This invention relates to a process for recovering high-purity benzyl benzoate from a reaction mixture obtained by the oxidation of toluene by molecular oxygen.
Benzyl benzoate is an important compound useful as raw material for perfumes and pharmaceuticals and applicable to other industries and a large number of processes for its manufacture have been reported. For example, Japan Kokai Tokkyo Koho Sho 56-39045 (1981) reports the recovery of benzyl benzoate by distillation of benzyl benzoate under reduced pressure from a reaction mixture produced by the oxidation of toluene by molecular oxygen. However, distillation alone has not yielded benzyl benzoate with such high purity as to be acceptable for use in perfumes. Likewise, Japan Kokai Tokkyo Koho Sho 53-95934 (1978) reports the recovery of benzyl benzoate by distillation from a reaction mixture produced by the oxidation of toluene by molecular oxygen, but high-purity benzyl benzoate is not obtained on account of the difficulty of separating fluorenone whose boiling point is close to that of BZB.
Japan Kokai Tokkyo Koho Sho 53-31639 (1978) describes a process for synthesizing benzyl benzoate by the transesterification of methyl benzoate with benzyl alcohol and an article in Industrial and Engineering Chemistry, Vol. 39, No. 10, pp.1300-1302 (1947) describes the synthesis of benzyl benzoate by the reaction of sodium benzoate with benzyl alcohol. Although these processes yield high-purity benzyl benzoate, they face a problem of high manufacturing cost because of the use of expensive catalysts and raw materials.
An object of this invention is to provide a process, free from the aforementioned shortcomings, for recovering benzyl benzoate in high purity at low cost.
This invention relates to a process for recovering benzyl benzoate which comprises distilling the residue remaining after removal of unreacted toluene and benzoic acid from a reaction mixture produced by the oxidation of toluene by molecular oxygen in the presence of a metal catalyst thereby separating a fraction of benzyl benzoate containing 80% by weight or more benzyl benzoate and simultaneously 10% by weight or less benzoic acid and 10% by weight or less fluorenone, purifying the fraction of benzyl benzoate by crystallization and recovering high-purity benzyl benzoate.
Benzyl benzoate (BZB) is known to be present as by-product in a reaction mixture produced by the oxidation of toluene by molecular oxygen in the presence of a catalyst. In general, the oxidation of toluene is carried out for the purpose of manufacturing benzoic acid and those catalysts which are commonly used for the reaction are based on heavy metals such as cobalt and manganese. As for the normal operating conditions inside the reactor, the temperature is 120-170xc2x0 C., the pressure is normal to 1 MPa and air is frequently used as molecular oxygen. A reaction mixture produced under any conditions, not limited to the aforementioned conditions or the purpose, may be used in this invention as long as it contains BZB and benzoic acid.
Either a continuous process or a batch process may be chosen for the oxidation reaction, though a continuous process is more economical. The main product to be produced by the oxidation of toluene is benzoic acid, but the following by-products besides unreacted toluene have been identified in the reaction mixture: water, formic acid, acetic acid, propionic acid, acetone, benzene, biphenyl, methylbiphenyl, dimethylbiphenyl, fluorene, fluorenone, toluic acid, phthalic acid, isophthalic acid, terephthalic acid, biphenylcarboxylic acid, methylbiphenylcarboxylic acid, biphenyldicarboxylic acid, and phenylbenzyl alcohol, compounds occurring as intermediates in the oxidation of toluene to benzoic acid such as benzaldehyde and benzyl alcohol, and esters formed by the esterification of benzyl alcohol or phenylbenzyl alcohol with a variety of carboxylic acids inside the reactor such as benzyl benzoate (BZB), benzyl acetate (BZA), benzyl toluate and benzyl biphenylcarb oxylate.
The reaction mixture is successively distilled to recover unreacted toluene and the main product benzoic acid. Simultaneously distilled in this step are components boiling lower than toluene such as water, formic acid, acetic acid, propionic acid, acetone and benzene and an intermediate fraction with a boiling point between those of toluene and benzoic acid such as benzaldehyde and benzyl alcohol. The unreacted raw material toluene and the intermediates benzaldehyde and benzyl alcohol are returned to the reactor for conversion to benzoic acid. Components boiling higher than benzoic acid, for example, biphenyl, methylbiphenyl, dimethylbiphenyl, fluorene, fluorenone, toluic acid, phthalic acid, isophthalic acid, terephthalic acid, biphenylcarboxylic acid, methylbiphenylcarboxylic acid, biphenyldicarboxylic acid, benzyl benzoate (BZB), benzyl acetate (BZA), and benzyl toluate are contained in the residue after the distillation of benzoic acid. Although the composition of the high-boiling components contained in the residue varies with the conditions for reaction and distillation, any residue containing at least a given amount, preferably 5% by weight or more, of BZB is acceptable for use in this invention. The residue may contain heavy metals such as cobalt or manganese originating from the oxidation catalyst, but it is advantageous to extract such heavy metals by hot water.
The BZB contained in the residue is distilled again and recovered as a BZB fraction. Either a continuous process or a batch process may be chosen for the distillation, though a continuous process is preferable economically. The BZB fraction obtained here is purified in the recrystallization step. Economical recovery of high-purity BZB, however, makes it necessary to maximize the recovery and the concentration of the BZB fraction in the distillation step.
The distillation in question is carried out below 270xc2x0 C., preferably below 250xc2x0 C., in order to prevent benzoate esters from thermally decomposing to benzoic acid as much as possible when the temperature at the bottom of the distillation column becomes too high and also to prevent benzoic acid from corroding the apparatus. As the boiling point of BZB is 323xc2x0 C., it is desirable to carry out the distillation under reduced pressure while keeping the pressure at the top of the distillation column preferably at 4.0 Kpa or less.
The number of plates for a distillation column used for the recovery of BZB from the residue will be 5 or more for satisfactory operation and the concentration of the BZB fraction can be controlled by reflux ratio. Providing the distillation column with an unnecessarily larger number of plates will raise the temperature at the bottom of the column on account of the pressure difference inside the column and occasionally cause such problems as formation of by-product benzoic acid and corrosion of the apparatus. The concentration of BZB in the BZB fraction to be obtained by this distillation is preferably 80% by weight or more, more preferably 90% by weight or more, in consideration of the recovery and purity in the following crystallization step. For this reason, the BZB fraction is obtained by carrying out the distillation preferably at 180-220xc2x0 C., more preferably at 190-210xc2x0 C., in case the pressure at the top of the distillation column is kept at 2.6 KPa.
The BZB fraction contains, in addition to BZB, such compounds as benzoic acid and fluorenone whose boiling point is close to that of BZB. In case the concentration of BZB in the BZB fraction is less than 80% by weight, the recovery of BZB in the following recrystallization step falls and, at the same time, benzoic acid and fluorenone crystallize together with BZB to lower the purity of the recovered BZB. The presence of less than 10% by weight of benzoic acid in the BZB fraction allows economical recovery of BZB while the presence of benzoic acid in excess of 10% by weight decreases the recovery of BZB in the crystallization step thereby making economical recovery of BZB difficult. In the presence of less than 10% by weight of fluorenone in the BZB fraction, BZB purified in the recrystallization step is colorless and transparent. On the other hand, when fluorenone is present in excess of 10% by weight in the BZB fraction, it crystallizes simultaneously with BZB and, as a result, BZB becomes colored yellow and unsuitable as raw material for perfumes and pharmaceuticals.
The BZB fraction is purified by crystallization to a purity acceptable as raw material for perfumes and pharmaceuticals. Known processes such as recrystallization, recrystallization and solvent washing, dispersive crystallization in solvent, multi-stage crystallization and continuous crystallization can be adopted for purification by crystallization. Advantageous among them is continuous crystallization and recrystallization, crystallization and solvent washing or dispersive crystallization in solvent. Recrystallization is carried out advantageously by dissolving BZB in a solvent that dissolves BZB moderately and is readily separable from BZB and then recrystallizing the BZB. In case the BZB fraction is obtained as liquid, the fraction is dissolved as it is in a solvent and allowed to recrystallize. Any solvent is suitable for this recrystallization if it shows a good solvent power against the BZB fraction above 10xc2x0 C. but such an insufficient solvent power against BZB below 10xc2x0 C. as to allow only BZB to crystallize and boils lower than BZB. Such solvents include acetone, methyl isobutyl ketone, methyl ethyl ketone, methanol, ethanol, isopropanol, butanol, tetrahydrofuran, dioxane, benzene, toluene, xylene, ethylbenzene, cyclohexane, methylcyclohexane, ethylcyclohexane, dimethyl ether, diethyl ether and petroleum ether. Two or more of such solvents may be mixed properly or an adequate amount of water may be added to these solvents. An aliphatic alcohol with 1 to 5 carbon atoms such as methanol, ethanol, propanol, butanol and pentanol or its mixture with water is a highly efficient solvent for the purification of BZB. In the case of a mixture of an alcohol and water, the alcohol to water ratio is preferably in the range from approximately 1:2 to 2:1.
Crystallization and solvent washing is effected by washing with a solvent the crystals formed by cooling the BZB fraction. A preferable procedure for washing is dispersing the crystals in a solvent followed by solid-liquid separation or to adding the BZB fraction to a solvent, allowing BZB to crystallize by cooling and submitting the resulting mixture to solid-liquid separation. In the course of crystallizing the BZB fraction by cooling, adding a solvent in a small amount or setting the crystallization temperature at a slightly higher level helps to form crystals of higher purity or facilitate filtration. Dispersive crystallization in solvent is preferably effected by adding the BZB fraction or the crystals thereof formed by cooling to a solvent to form a dispersion of the crystals. In either case, any solvent may be used satisfactorily as long as it dissolves the impurities present in the BZB fraction and it is not always necessary for the solvent in question to have an ability to dissolve BZB. As the impurities and BZB behave similarly in solvent solubility, however, a solvent capable of dissolving BZB is used. Preferable solvents here are the same as the aforementioned solvents for recrystallization. Whenever the purity falls short of the target level or there occurs a need to remove the adhered solvent after completion of the aforementioned purification by crystallization, an after-treatment is performed in the same as in the case of recrystallization to be described below.
Recrystallization is effected by dissolving the BZB fraction or the crystals obtained therefrom in a solvent and cooling the resulting solution to a temperature below the melting point of BZB, preferably to below 10xc2x0 C., to separate the crystals. Cooling to below 5xc2x0 C. is preferable for an efficient recovery of BZB. However, cooling to below xe2x88x9230xc2x0 C. is not desirable as this will occasionally cause components other than BZB to separate. Use of 5 parts by weight or less of the solvent per 1 part by weight of the BZB fraction is adequate. An excess of the solvent relative to the BZB fraction is undesirable because the recovery of BZB during recrystallization decreases. It is to be noted that the BZB fraction is liquid not only at the time when it distills out but also usually at normal temperature and the fraction as liquid is occasionally dissolved in a solvent. In this invention, dissolving the BZB fraction and crystallizing it in this manner is also referred to as recrystallization. Recrystallization is preferably effected with stirring and the separated crystals of BZB are collected by a procedure for solid-liquid separation such as centrifugal filtration and vacuum filtration.
Since the mother liquor containing the impurities adheres to the crystals, it is necessary to wash the crystals with the same solvent as used in the recrystallization step to obtain high-purity BZB. The crystals can be washed either by adding a washing solvent directly to the surface of the collected crystals or by throwing the crystals in a solvent and filtering them again. In either case, washing of 1 part by weight of the crystals requires 0.5 part by weight or more of the washing solvent. Washing with less than 0.5 part by weight of the solvent cannot remove the impurities in the mother liquor sufficiently and the purity of BZB deteriorates. On the other hand, washing with too much solvent decreases the recovery of BZB, which is not economical.
The solvent-washed crystals are melted by heating to above 18xc2x0 C., which is the melting point of BZB, and the adhered solvent is distilled off under reduced pressure. In this manner, it is possible to recover economically colorless transparent BZB with a purity of 99.5% or more, useful as raw material for perfumes and pharmaceuticals and applicable to other industrial uses.


Different configurations of power distribution boxes are assembled from a common set of components. A housing may receive any of several bus assemblies having taps of differing configurations. A fuse holder that protects portions of a bus assembly inserted into the housing is attached with the housing.

1. Field of the Invention
The invention relates to electrical connector systems and methods of assembling the same.
2. Discussion
Electrical connectors of automotive vehicles may connect a power source, e.g., a battery, with a wiring harness. The wiring harness may include several electrical leads that electrically connect with devices that require power. Different wiring harnesses may require different electrical connectors.

Automotive electrical connector system and method of assembling same


A method and system are provided for finishing a concrete floor that exce approximately 50 feet in width. A riding trowel of the type that forms a windrow of loosened concrete material in its wake is positioned on the concrete floor. The riding trowel has a straight edge coupled thereto by a support assembly that positions the straight edge to cross the windrow at a substantially perpendicular angle thereto within line-of-sight of an operator. A power assembly is coupled between the straight edge and the riding trowel for independently controlling vertical and pivoting movement of the straight edge. The riding trowel is driven on the concrete floor and the straight edge is moved along the concrete floor simultaneously with the riding trowel.

The formation of flat or "super flat" concrete floors is the goal of every large construction project. In the construction industry, it is well known that a flat floor will produce a flatness measurement in terms of F(F) numbers in the range of 35-50. Super flat floors, however, will produce F(F) numbers in the range of 50-100. For a detailed description of floor flatness measurements using the industry-standard F-number system, see "Standard Test Method for Determining Floor Flatness and Levelness Using the F-Number System," American Society for Testing and Materials (ASTM) standard designation E 1155.
To achieve flat or super flat concrete floors, the construction industry has for years followed one of two basic methodologies. The first of these will now be explained with the aid of FIG. 1. In FIG. 1, concrete is poured between forms represented by lines 10 and 12 to form a strip 14 of concrete. For reasons that will become apparent below, strip 14 can be up to 50 feet in width but more typically is only 15-30 feet in width and can be as long as the building being constructed (e.g., several hundred feet). Once strip 14 is "struck off" between forms 10 and 12 and has hardened such that only the top 1/8 to 3/16 of an inch remains plastic, the finishing of strip 14 to flat or super flat status is begun.
A riding trowel 16 is positioned on strip 14 and driven thereon to stir up the still-plastic top layer of strip 14. Riding trowel 16 is well known in the art and employs rotating finishing blades or pans in contact with strip 14 to support and propel riding trowel 16 on strip 14. The type of finishing blade(s) chosen is based on the degree of hardness of the concrete with the blade(s) being changed as the concrete gets harder. After each pass of riding trowel 16, it is necessary to cut down high areas of concrete and fill low areas with the excess concrete scraped from the high areas. To do this, workers 20 are positioned on either side of strip 14 and are each equipped with a straight edge tool 22 having a handle 24. One such straight edge tool/handle combination is disclosed by Naser et al. in U.S. Pat. No. 4,702,641. Workers 20 manipulate their straight edge tool 22 (using handle 24) back and forth on strip 14 to cut down high areas of concrete and fill the low areas with the scraped concrete from the high areas.
In recent years, a flat disk or pan has been mounted on riding trowel 16 in place of the blades to form a pan machine as it is known. The pan machine accomplishes the function of several types of blades. This has reduced the number of man-hours required for finishing as the pan machine need not even be used until the later phases of hardening. However, this also means that the window of time for proper cutting of high areas and filling of low areas is reduced thereby making the timing of all finishing operations critical.
Each pass of riding trowel 16 (equipped with either blades or pans) also forms one or more windrows, represented by swirled lines 18, in the wake of riding trowel 16. Windrows 18 are small continuous piles of loosened concrete material that are spun out most prominently to the perimeter of the finishing blades (not shown), or between two non-overlapping pans (not shown), mounted and rotating on riding trowel 16. Since windrows 18 are essentially bumps that disrupt the flatness of strip 14 and since the concrete is in its "almost hard" phase, windrows 18 must be cut and smoothed quickly after their formation. To do this, workers 20 manipulate their straight edge tool 22 (using handle 24) back and forth on strip 14 to smooth out windrows 18. To keep up with riding trowel 16, several workers 20 are typically required on either side of strip 14.
This approach to concrete floor finishing has several disadvantages. Super flat floors can only be achieved if workers 20 stay off strip 14. Therefore, the cut/fill operation and the cutting/smoothing of windrows 18 must be accomplished from either side of strip 14 since effective manipulation of straight edge tool 22 is limited to distances of 15-20 feet. In addition, because windrows 18 are being crossed by straight edge tool 22 at angles between 0.degree. and 45.degree., smaller windrows 19 are continuously created at the outboard ends of straight edge tool 22. Depending on the level of flatness that must be achieved, keeping up with riding trowel 16 can also be a problem as workers 20 may have to work one area of strip 14 more than another. Further, if strip 14 is exposed to a hot sunny environment (as is often the case in summertime floor finishing), windrows 18 can begin to set-up before being cut thereby making the worker's job more difficult or impossible in the worst case scenario.
As mentioned above, the flatness of strip 14 is very important. For this reason, strip 14 is typically only 15-30 feet in width because larger width strips become difficult or impossible to smooth at their centers as workers either cannot reach the center or cannot see what they are doing at the center. Thus, wider width strips (i.e., 30-50 feet) are generally finished at their centers using only riding trowel 16 which limits their flatness to an F(F) number of 30-40 at best. Further, even if the narrower width strips are finished to satisfactory F(F) numbers, adjacent strips necessarily have joints therebetween. These joints can never be finished to the higher F(F) numbers of the strips themselves and therefore will always present potential problems.
Finally, the narrow-width, labor-intensive concrete finishing described above is limited in the amount of concrete that can be finished in a day. In general, an industry-accepted standard is that a crew can finish 9000 square feet per day. However, for large warehouses having 250,000 square feet or more of floor, strip pouring and finishing is not an economical option.
To accommodate large floor construction, the concrete industry in the late 1980's developed a second (now prior art) concrete floor construction that relies on laser screed placement of concrete. In laser screed placement, widths of concrete can exceed 100 feet and recently a pour of 250,000 square feet of concrete was accomplished in a single day. This avoids numerous joints between strips and results in an average cost savings of $1 per square foot. However, these wide-width pours require workers equipped with straight-edge tools to walk on the concrete floor in order to perform the cut/fill operation and the cutting/smoothing of windrows left by the riding trowel. Unfortunately, the damage caused by worker footprints almost offsets the good being achieved by the straight edge tool. Therefore, most contractors rely only on the riding trowel equipped with pans (i.e., a pan machine) to finish a concrete floor that is poured in widths of approximately 50 feet or more. The industry-accepted drawback to finishing only with a riding trowel is a floor flatness that can only achieve an F(F) number in the range of 40-50.

Bump cutting for wide-pour concrete floors

Neuber Concrete, A Division of J. F. Neuber Jr. General Contractor, Inc.


Apparatus for providing optical radiation (15), which apparatus comprises an optical input (13), a coupler (2), a first semiconductor amplifier (3), a controller (4), a preamplifier (61), a power amplifier (62) and an output fibre (5), wherein: the optical input (13) is for receiving input optical radiation (14); the optical input (13) is connected in series to the coupler (2), the first semiconductor amplifier (3), the preamplifier (61), the power amplifier (62), and the output fibre (5); the apparatus being characterized in that: the first semiconductor amplifier (3) comprises a waveguide (6) having a low reflecting facet (8); the first semiconductor amplifier (3) is in a double pass configuration such that the low reflecting facet (8) is connected to both the optical input (13) and the preamplifier (61) via the coupler (2); and the controller (4) is configured to cause the waveguide (6) of the first semiconductor amplifier (3) to operate in saturation thereby enabling the first semiconductor amplifier (3) to reduce non-linear effects in the preamplifier (61), the power amplifier (62), and the output fibre (5).

Industrial lasers such as fibre lasers and disk lasers have important applications for marking, cutting, scribing, welding, additive manufacturing, and other industrial processing of materials. The lasers are used in many industries including consumer electronics, medical devices, automotive, and aerospace. The lasers can be pulsed or continuous wave. Typical pulse lengths that are achievable range from a few picoseconds through nanoseconds, microseconds and milliseconds. The pulse repetition rate is controlled electronically and can be varied over a wide range.
As power levels and intensities increase, so do problems associated with non-linear effects, for example, spectral noise, temporal noise, speckle, non-linear wavelength conversion of the optical radiation, and self Q-switching. These non-linear effects are undesirable in industrial processing systems where repeatability of a process is required. For example, wavelength conversion causes errors in optical focussing systems and can reduce the optical power able to be delivered to a material, and self Q-switching can destroy optical amplifiers and optical fibres in the laser system.
A partial solution is to use a superluminescent diode as a seed laser in a master oscillator power amplifier in order to increase the bandwidth of the optical radiation and thus reduced the onset of non-linear effects. This solution has allowed power levels to be increased. However, as the power level is increased further, the power amplifier can suffer from non-linear effects. Moreover, the superluminescent diode can start to emit coherent laser radiation, that is, the superluminescent diode can start to lase. This further exacerbates non-linear effects in the power amplifier and in optical fibre delivery systems, and can lead to catastrophic failure of the power amplifier and optical fibre delivery system.
Spatial instabilities are undesirable because they affect the beam pointing stability of the optical radiation which is detrimental in industrial processing applications. This is a particular problem for multimode power amplifiers and multimode beam delivery fibres. The problem becomes more acute as power levels are increased owing to the aforementioned non-linear effects. In addition, spectral and temporal noise of seed lasers can exacerbate these non-linear effects.
There is a need for apparatus for providing optical radiation that avoids or reduces the aforementioned problems.
The Invention
According to the present invention there is provided apparatus for providing optical radiation, which apparatus comprises an optical input, a coupler, a first semiconductor amplifier, a controller, a preamplifier, a power amplifier, an output fibre, and a resonant cavity, wherein:
the optical input is for receiving input optical radiation;
the optical input is connected in series to the coupler, the first semiconductor amplifier, the preamplifier, the power amplifier, and the output fibre, and the resonant cavity;
the resonant cavity comprises a non-linear crystal;
the resonant cavity is connected to the optical input thereby forming a ring laser comprising the coupler, the first semiconductor amplifier, the preamplifier, the power amplifier, the output fibre, and the resonant cavity;
the first semiconductor amplifier comprises a waveguide having a low reflecting facet;
the first semiconductor amplifier is in a double pass configuration such that the low reflecting facet is connected to both the optical input and the preamplifier via the coupler;
the controller is configured to cause the waveguide of the first semiconductor amplifier to operate in saturation thereby enabling the first semiconductor amplifier to reduce non-linear effects in the preamplifier, the power amplifier, and the output fibre;
the resonant cavity operates to provide optical feedback in the form of the input optical radiation; and
the first semiconductor amplifier is configured to supply optical radiation to the preamplifier in the event that the optical feedback is lost in order to prevent failure of the power amplifier.
Examples of non-linear effects include spectral noise, temporal noise, speckle, non-linear wavelength conversion of the optical radiation, and self Q-switching.
The first semiconductor amplifier may be defined by an optical lasing threshold in the absence of the input optical radiation. The controller may be configured to cause the waveguide of the first semiconductor amplifier to emit an output signal having an output power greater than the optical lasing threshold when the input optical radiation is present. Preferably the controller may be configured to cause the waveguide of the first semiconductor amplifier to emit an output signal having an output power at least two times greater than the optical lasing threshold when the input optical radiation is present. More preferably the controller may be configured to cause the waveguide of the first semiconductor amplifier to emit an output signal having an output power at least three times greater than the optical lasing threshold when the input optical radiation is present.
The controller and the first semiconductor amplifier may be such that the first semiconductor amplifier lases in the absence of the input optical radiation, and the first semiconductor amplifier is prevented from lasing by the presence of the input optical radiation.
The ability to operate the first semiconductor amplifier at power levels that exceed its optical lasing threshold allows significant increases in the achievable output powers of pulsed and continuous wave laser systems without incurring the limitations caused by non-linear effects such as, for example, stimulated Brillouin scattering, stimulated Raman scattering, and four-wave mixing. The first semiconductor amplifier, when operated in saturation, can improve the signal to noise ratio present in the input optical radiation. In addition, the first semiconductor amplifier replicates the spectral properties of the input optical radiation. Reducing the noise amplitude of the optical radiation entering into the power amplifier reduces the amount of non-linear effects such as stimulated Raman scattering. It therefore permits larger signals to be input into the power amplifier before the non-linear effects become problematic. For optical fibre laser systems, its inclusion therefore allows an increase in amplification without requiring an additional optical fibre amplification stage.
Surprisingly, it is possible to operate the first semiconductor amplifier at intensity levels that would normally cause it to be unstable or lase. This is achieved by optically injecting optical radiation from an optical source which is then amplified by the first semiconductor amplifier in a double pass configuration, and then output via the output fibre. The power of the input optical radiation is selected such that the first semiconductor amplifier does not lase. The power of the input optical radiation is preferably greater than the power of reflections that make the first semiconductor amplifier lase at the optical lasing threshold.
The controller may be configured to control an optical gain of the first semiconductor amplifier such that the optical gain is reduced in the absence of the input optical radiation thereby preventing the first semiconductor amplifier from lasing. Advantageously, reducing the optical gain by reducing the drive current into the first semiconductor amplifier can be used to prevent catastrophic failure of the laser system when the input optical radiation is not present.
The apparatus may include an optical source for providing the input optical radiation. The optical source may be connected to the optical input. The optical source may be selected such that the input optical radiation has a power greater than a power of reflections from the apparatus that cause the first semiconductor amplifier to lase when the input optical radiation is not present.
A particularly attractive arrangement is where the optical source is a superluminescent diode. The optical source acts as a seed laser which provides a predetermined spectral content of the optical radiation, and the first semiconductor amplifier provides amplification. The result is a broadband source which can act as a seed laser in a high power industrial pulsed laser, reducing non-linear effects, and thus enabling much higher output powers to be achieved with less amplifying stages. This provides advantages in output power, cost, power consumption, and simplicity.
The waveguide may be a curved waveguide. This allows the attainment of higher power in the optical radiation emitted by the apparatus.
The apparatus may include a saturable absorber between the coupler and the first preamplifier in order to reduce noise between pulses of the optical radiation.
The apparatus may include a second semiconductor amplifier configured to receive the input optical radiation prior to amplification by the first semiconductor amplifier.
The second semiconductor amplifier may be operated in continuous wave operation below its lasing threshold. This can prevent catastrophic failure of the power amplifier in the event that the input optical radiation is interrupted for any reason.
The input optical radiation may comprise a pulse train having a pulse repetition frequency, and the controller may cause the first semiconductor amplifier to down-select the pulse repetition frequency.
The apparatus may include a mode locked laser to provide the pulse train.
The apparatus may include a power splitter to direct the pulse train to a plurality of amplifier chains. Each amplifier chain may include a first semiconductor amplifier.
The input optical radiation may be provided by a random fibre laser. A random fibre laser can provide an output that has a higher signal to noise ratio than conventional fibre lasers. When combined with the signal to noise improvements obtainable by operating the first semiconductor amplifier in saturation, this leads to a new class of fibre lasers that can achieve higher powers before non-linear effects such as stimulated Raman scattering becomes a problem.
The resonant cavity operates through non-linear optical effects that are highly dependent on the instantaneous optical power and instantaneous wavelength of the output radiation. Operating the first semiconductor amplifier in saturation reduces the spectral noise, temporal noise, and non-linear wavelength conversion of the output radiation, which therefore results in a far more stable operation of the resonant cavity and thus a lower noise and more stable frequency converted radiation. Such a configuration can also help reduce catastrophic failure of the ring laser in the event that feedback from the resonant cavity is lost, particularly when setting up and aligning the apparatus. This is because the first semiconductor amplifier can be configured to output optical radiation in the absence of the optical radiation provided by the optical source.
The input optical radiation may be provided by a semiconductor diode. The semiconductor diode may be a superluminescent diode. The semiconductor diode may comprise a curved waveguide.
The apparatus may include an optical attenuator located between the optical input and the coupler. The optical attenuator is preferably a variable optical attenuator. The controller may adjust the optical attenuator such that the first semiconductor amplifier is operated in saturation.
The output fibre may be a hollow core fibre. The output fibre may be a polarisation maintaining hollow core fibre.
The power amplifier may be a single mode amplifier.
The power amplifier may be a multimode amplifier. The apparatus may include an optical mode mixer between the preamplifier and the power amplifier. The inclusion of the optical mode mixer is advantageous because it reduces spatial and temporal instabilities in the power amplifier, thus reducing pointing instabilities in material processing applications.
The power amplifier may comprise an optical fibre amplifier. Alternatively or additionally, the power amplifier may comprise a free-space solid state amplifier such as a rod amplifier or a slab amplifier.
The apparatus may include an optical isolator between the preamplifier and the power amplifier.
The apparatus may comprise an optical filter between the optical input and the first semiconductor amplifier.
The apparatus may comprise an optical isolator between the optical input and the coupler.
The coupler may be an optical circulator.
The apparatus may comprise an optical isolator between the coupler and the preamplifier.
The apparatus may include a visible light source connected to a wavelength division multiplexer. The wavelength division multiplexer may be located between the coupler and the power amplifier. The visible light source may have a wavelength between 500 nm and 670 nm, and preferably between 600 nm and 670 nm. The provision of a visible light source is useful when installing the apparatus in other equipment, and for detecting faults in the power amplifier and the output fibre.
The apparatus may include a depolariser between the coupler and the preamplifier.
The apparatus may include an output beam optic at the distal end of the output fibre. The output beam optic may comprise at least one of an isolator, a collimating lens system, an anti-reflection coating, an optical detector, and a source of visible optical radiation.
The invention also provides a method for providing optical radiation, which method comprises:
providing an optical input, a coupler, a first semiconductor amplifier, a preamplifier, a power amplifier, an output fibre, and a resonant cavity that are configured in series;
providing a non-linear crystal in the resonant cavity;
amplifying input optical radiation received by the optical input by the first semiconductor amplifier, the preamplifier, and the power amplifier;
outputting the optical radiation from the power amplifier to the resonant cavity via the output fibre;
forming a ring laser by connecting the resonant cavity to the optical input;
configuring a controller to cause the waveguide to operate in saturation thereby enabling a reduction of at least one of spectral noise, temporal noise, and non-linear wavelength conversion of the optical radiation;
using a detector to detect for an absence of the input optical radiation; and
reducing an optical gain of the first semiconductor amplifier in order to prevent the first semiconductor amplifier from lasing,
wherein
the first semiconductor amplifier comprises a waveguide having a low reflecting facet;
the first semiconductor amplifier is in a double pass configuration such that the low reflecting facet is connected to both the optical input and the preamplifier via the coupler.
The first semiconductor amplifier may be defined by an optical lasing threshold in the absence of the input optical radiation, and the method may include the steps of providing the input optical radiation, and causing the waveguide to emit an output signal having an output power greater than the optical lasing threshold. The output signal may have an output power greater than two times the optical lasing threshold. The output signal may have an output power greater than three times the optical lasing threshold.
The method may include the step of preventing the first semiconductor amplifier from lasing by providing the input optical radiation.
The method may include the step of removing the optical radiation, and reducing an optical gain of the first semiconductor amplifier thereby preventing the first semiconductor amplifier from lasing.
The method may include the step of selecting an optical source which provides the input optical radiation such that the input optical radiation has a power greater than a power of reflections from the apparatus that causes the first semiconductor amplifier to lase when the input optical radiation is not present.
The present invention also provides a method for preventing failure of a ring laser, which method comprises:
providing an optical input, a coupler, a first semiconductor amplifier, a preamplifier, a power amplifier, an output fibre, and a resonant cavity that are configured in series;
providing a non-linear crystal in the resonant cavity;
forming the ring laser by connecting the resonant cavity to the optical input;
amplifying input optical radiation received by the optical input by the first semiconductor amplifier, the preamplifier, and the power amplifier;
outputting optical radiation from the power amplifier to the resonant cavity via the output fibre;
configuring a controller to cause the waveguide to operate in saturation thereby enabling a reduction of at least one of spectral noise, temporal noise, and non-linear wavelength conversion of the optical radiation;
causing the resonant cavity to provide optical feedback in the form of the input optical radiation; and
configuring the first semiconductor amplifier to supply optical radiation to the preamplifier in the event that the optical feedback is lost in order to prevent failure of the power amplifier,
wherein
the first semiconductor amplifier comprises a waveguide having a low reflecting facet; and
the first semiconductor amplifier is in a double pass configuration such that the low reflecting facet is connected to both the optical input and the preamplifier via the coupler.
The waveguide may be a curved waveguide.
The invention also provides an apparatus for providing optical radiation according to the method of the invention.
The invention also provides a usage of a first semiconductor amplifier in saturation for improving signal to noise ratio and thereby reducing non-linear optical effects in optical fibre amplifiers.
The invention also provides a usage of a first semiconductor amplifier for performing the method of the invention.
The method of the invention may include a step or steps as required to utilize the above mentioned optional aspects of the apparatus of the invention.


A motion analysis system records a sequence of image frames of an event at a fast frame rate. A 2-D or 3-D still image depicting the kinetics of the multiple recorded, images is constructed by spatio-temporal visualization techniques. In the spatio-temporal (ST)-2-D technique, a path of pixels is defined showing travel of an object over time. The path of pixels of each image frame is represented in the ST-2-D image as a horizontal line of pixels. Each line in the vertical or horizontal direction is taken from one frame so that the sequence of lines represents the sequence of image frames of the event. In the ST-3-D visualization technique, a closed curve path of pixels is defined and represented in the ST-3-D image using 3-D graphical display techniques.

This invention relates in general to a motion analysis system which records a sequence of images of an event at a fast frame rate and plays back the images of the event at a slower frame rate so that the event may be analyzed. More particularly, this invention relates to visualization techniques for temporally acquired sequences of images which allow the visualization in one still image of the kinetics of a multiple image recording session.
Motion analysis systems are useful for analyzing rapidly changing events. One type of motion analysis system records a great number of images during an event at a high or fast image frame rate and reproduces the image frames more slowly at a lower frame rate. Thus, any movement occurring during the event may be analyzed in a step by step progression. Applications for a motion analysis system include, malfunctions in high speed machinery, movements of an athlete, testing of safety equipment, shattering of an object, etc. One type of motion analysis system is disclosed in commonly assigned U.S. Pat. No. 4,496,995 issued Jan. 29, 1985. As disclosed in the latter patent, the motion analysis system/fast frame recorder includes a video camera, a variable speed processor and a video display monitor. The camera is read out in block format so that, a plurality of lines of video information that correspond to rows of photosites in the camera solid state imager, are simultaneously recorded on magnetic tape in parallel longitudinal tracks. During playback, the magnetic tape is played back at a reduced tape speed. A plurality of parallel video signals reproduced from parallel tracks on the tape are processed into a serial video signal which may be used with standard video monitors. A magnetic tape motion analysis system is advantageous, because of he ability to record a large number of image frames and because of the nonvolatility of the image storage.
Another type of motion analysis system is disclosed in commonly assigned patent application Ser. No. 07/431,010 filing date Nov. 2, 1989. As disclosed in this patent, the motion analysis system includes a video camera, a solid state memory, a video processor, and a video display monitor. A sequence of images of an event is stored in digital format in the solid state memory. Stored frames are played back in a sequence of full frames. Alternatively, individual images are randomly accessed for display either as individual frames or in any sequence of frames desired.
There are applications where it would be desirable to visualize in a single still image the kinetics of a portion of or the entire sequence of images of a recorded or stored event.

Visualization techniques for temporally acquired sequences of images


Methods and systems to control access to a predetermined service or area. An access code is read from a portable electronic device of a user using an access terminal at a service site. As a result of reading the access code from the portable electronic device, access-related information is transmitted to the portable electronic device.

Access control systems typically require a user to present to the system something that is intended to serve as evidence that the user is authorized to receive access from the system. For example some systems grant access to a user based on a token (e.g., an identification card or a key fob) in the user's possession. The token can be an RFID (radio-frequency identification) tag or other information-storage device. In other systems, access is granted to a user based on information that the user provides to the system, such as a password. Some systems require multiple items from a user, fir example, both a token and a password.
US20110291798A1 describes a system in which an electronic device, such as a smartphone, stores a digitally signed physical access rights file. An individual uses this rights file to gain access to a restricted area only after self-authenticating to the device. A physical access control system receives the rights file, validates it, and determines whether to permit passage through a physical barrier. An access control gateway may transmit an authorization code to the electronic device and the physical barrier system, whereby passage is only permitted if the barrier system subsequently receives the authorization code from the electronic device using near field communications.
Certain elevator systems, in particular those installed in commercial buildings and having several elevator cars that operate in parallel to service individual elevator calls, e.g., in hotels or office buildings, require a user to present to the system something that is intended to serve as evidence that the user is authorized to use the elevator system. For example, in an elevator system having a destination control system, the user presents an RFID card to a floor terminal to automatically call an elevator. An identification code read from the RFID card is used to determine if the user is authorized to use the elevator system and what destination floor is stored for that user.
Such access control systems and elevator systems are already automated to a certain degree to facilitate usability. Further improvements as to usability could be advantageous, in particular without sacrificing on security. This is addressed by at least some of the embodiments covered by the claims.

Access control system with feedback to portable electronic device