A liquid crystal lens is provided and includes a first electrode, a second electrode disposed opposite to the first electrode, and a liquid crystal layer, including liquid crystal molecules having refractive anisotropy, disposed between the first electrode and the second electrode, the liquid crystal molecules being changed in alignment depending on voltage applied by the first electrode and the second electrode, thereby to form such a phase difference distribution that phase difference with respect to an incident beam of a fundamental wavelength varies from 0 to 2πβ along the predetermined direction, β being an integer of 2 or more, and to yield such a lens effect that focal lengths for a plurality of incident beams of different wavelengths including the fundamental wavelength are equal to one another.

The present disclosure relates to a liquid crystal lens using liquid crystal molecules having refractive anisotropy to generate a lens effect, and a display device using the liquid crystal lens.
In the past, a binocular or multi-view stereoscopic display device, which achieves stereoscopy through presenting a parallax image to both eyes of a viewer, has been known. As a method for achieving such a stereoscopic display device, for example, a two-dimensional display device such as liquid crystal display is combined with an optical device (parallax separation unit) for three-dimensional display for deflecting display image light from the two-dimensional display device in a plurality of view angle directions. As the optical device for three-dimensional display, a cylindrical lens array (lenticular lens) 302, including a plurality of cylindrical lenses 303 arranged in parallel, is used, for example, as shown in FIG. 18. The lenticular lens 302 is disposed opposite a display surface of a display panel 301 including the two-dimensional display device. Each cylindrical lens 303 is arranged to extend in a longitudinal direction to the display surface of the display panel 301 so as to have refracting power in a lateral direction. A plurality of display pixels are regularly arranged in a two-dimensional manner on the display surface of the display panel 301. Two or more pixels are disposed behind one cylindrical lens 303, and beams emitted from the pixels are directed in different horizontal directions by refracting power of the lens to meet binocular parallax, thereby enabling naked-eye stereoscopy.
FIG. 18 shows an example of binocular stereoscopic display, where adjacent two pixel arrays 301R and 301L on the display surface of the display panel 301 are allocated to each cylindrical lens 303. One pixel array 301R displays a right-parallax image, and the other pixel array 301L displays a left-parallax image. Each of the displayed parallax images is directed to a laterally separated light path 402 or 403 by each cylindrical lens 303. Consequently, when a viewer 400 views such a stereoscopic display device in a predetermined direction and from a predetermined position, the right and left parallax images appropriately reach right and left eyes of the viewer 400, respectively, and the viewer thus senses a stereoscopic image.
Similarly, for multi-view stereoscopic display, a plurality of parallax images, which are taken at positions and in directions corresponding to three or more visual points, are evenly allocated and displayed within a lateral lens pitch of the cylindrical lens 303. Consequently, three or more parallax images are emitted in continuous, different angle ranges and focused by the lenticular lens 302. In this case, a plurality of different parallax images are sensed in correspondence to positions and directions of changed visual lines of the viewer 400. A more realistic stereoscopic effect may be obtained with increase in number of the parallax images in correspondence to changed visual points.
As the lenticular lens 302, for example, a resin-molded lens array, which is fixed in shape and thus fixed in lens effect, may be used. In this case, since the lens effect is fixed, a special display device for three-dimensional display is given. A switchable lens array element with a liquid crystal lens may be also used as the lenticular lens 302. In the case of the switchable lens array element with a liquid crystal lens, since presence or absence of a lens effect may be electrically switched, a display mode may be switched between two display modes, namely, two-dimensional display mode and three-dimensional display mode, through combining the lens array element with a two-dimensional display device. In other words, in the two-dimensional display mode, the lens array is set to be in a no-lens-effect state (no-refracting-power state) so as to transmit display image light from the two-dimensional display device without any change. In the three-dimensional display mode, the lens array is set to be in a lens-effect state so as to deflect the display image light from the two-dimensional display device in a plurality of view angle directions, so that stereoscopy is achieved.
A configuration example of the switchable (variable) lens array element with a liquid crystal lens is described with reference to FIGS. 19A and 19B. The figures mainly show a structure of an electrode portion while omitting other components such as a substrate and an alignment film. Moreover, the figures show the configuration in a simplified manner for illustrating a principle of generation of a lens effect in the lens array element. The variable lens array element includes transparent first and second substrates made of, for example, a glass material, and a liquid crystal layer 130 sandwiched between the first and second substrates. The first and second substrates are oppositely disposed with a space d.
A first electrode 111 including a transparent conductive film such as an ITO (Indium Tin Oxide) film is uniformly formed over almost the whole surface on the first substrate. In addition, a first alignment film is formed on the first substrate in a manner to contact with the liquid crystal layer 130 via the first electrode 111. Second electrodes 121Y including a transparent conductive film such as an ITO film are partially formed on the second substrate. In addition, a second alignment film is formed on the second substrate in a manner to contact with the liquid crystal layer 130 via the second electrodes 121Y.
The liquid crystal layer 130 includes liquid crystal molecules 131, where an alignment direction of the liquid crystal molecules 131 is changed depending on voltage applied by the first electrode 111 and the second electrodes 121Y, so that the lens effect is controlled. Each liquid crystal molecule 131 has refractive anisotropy, and thus, for example, has a structure of an optical indicatrix having different refractive indexes to a passing beam between a long-side direction and a short-side direction. The liquid crystal layer 130 is electrically switched between a no-lens-effect state and a lens-effect state depending on voltage applied by the first electrode 111 and the second electrodes 121Y.
In the lens array element, as shown in FIG. 19A, the liquid crystal molecules 131 are uniformly aligned in a predetermined direction defined by the first and second alignment films in a normal condition with applied voltage of 0 V. Therefore, a wave front 201 of a passing beam is a plane wave, showing the no-lens-effect state. In the lens array element, since the plurality of second electrodes 121Y are separately arranged from one another with a predetermined space, when a predetermined drive voltage is applied between the first electrode 111 and the second electrodes 121Y, deviation occurs in electric field distribution within the liquid crystal layer 130. In other words, an electric field is generated such that field strength is increased in accordance with the applied drive voltage in a portion corresponding to a region where each second electrode 121Y is formed, and decreased in a portion nearer to the center of an opening between the plurality of second electrodes 121Y. Therefore, alignment of the liquid crystal molecules 131 is changed in accordance with field strength distribution as shown in FIG. 19B. Consequently, the wave front 202 of a passing beam is changed, leading to a lens-effect generation state.
Such a variable lens array element may be used to equivalently generate a lens effect of a lenticular lens. Consequently, switchable display may be made between two-dimensional display mode and three-dimensional display mode.
Recently, a liquid crystal lens, which uses such an optical characteristic of a liquid crystal changed depending on applied voltage, has been increasingly developed. Use of a liquid crystal eliminates need of mechanically movable portions, which contributes to reduction in size and weight of a lens unit. "Switchable electro-optic diffractive lens with high efficiency for ophthalmic applications", PNAS, 103, 16, 2006, pp. 6100-6104 proposes a method to generate a Fresnel-lens-like lens effect by a liquid crystal lens in order to widen an aperture of a lens and to improve performance of the lens. In the above non-patent document, an electrode is patterned in a concentric configuration to generate the Fresnel-lens-like lens effect. Japanese Unexamined Patent Application Publication No. 63-249125 and Japanese Unexamined Patent Application Publication No. 5-100201 also describe methods to generate a Fresnel-lens-like lens effect by using a liquid crystal. A liquid crystal lens is formed like a Fresnel lens as in the non-patent document, and therefore an aperture may be widened and besides the amount of liquid crystal material to be used may be decreased, leading to reduction in cost. Furthermore, the non-patent document describes an example of achieving glasses using the liquid crystal lens.


When engine operation falls in a predetermined zone wherein it is necessary to attenuate engine surging or the like type of engine operating phenomenon, and wherein mapped adaptive update value data is required to exhibit a different resolution to the adaptive update value data which is contained in the remainder of the map not included in the predetermined zone, the operation of the engine in the predetermined zone is detected and an indication of the same set. While the indication is set, updating of the mapped data which corresponds to the predetermined operational zone, is inhibited. In some embodiments mapped data which corresponds to the predetermined operational zone is set in a separate memory section and updated in a manner different from the manner in which the data which does not correspond to the special zone, is updated.

1. Field of the Invention
The present invention relates generally to an air/fuel ratio control system for an internal combustion engine and more specifically to an air-fuel ratio control system which utilizes the output of a dual oxygen concentration sensor arrangement to achieve feedback control of the fuel supply system.
2. Description of the Prior Art
The use of a so called three-way catalytic converter in an automotive exhaust system is well known. However, in order to achieve the simultaneous reduction of HC, CO and NOx, it is necessary to maintain the air-fuel mixture supplied to the combustion chamber or chambers of the engine at or very close to the stoichiometric air-fuel ratio (A/F) in order to maximize the conversion efficiency. The use of O2 sensors for this purpose is also widely known.
However, as the output characteristics Of O2 sensors vary from one sensor to another, a problem is encountered in that the unit to unit deviations in the sensors induce errors in the feedback control of the fuel supply whereby the stoichiometric air-fuel ratio is not maintained in the desired manner and the efficiency of the three-way conversion in the catalytic converter is inhibited.
To overcome this problem is has been proposed in JP-A-58-72647 to use two O2 sensors. One of the sensors is disposed in an exhaust conduit upstream of a 3-way catalytic converter while the other is disposed downstream thereof. The outputs of the two O2 sensors are fed to a control unit which in turn controls the amount of fuel injected by a fuel injector disposed in the engine induction system.
Similar arrangements are also disclosed in JP-A-1-113552 and U.S. Pat. No. 3,939,654 issued on Feb. 24, 1976 in the name of Creps.
An example of the control implemented in connection with this type of system is depicted in flow chart form in FIGS. 23 and 24. The routine depicted in FIG. 23 is such as to utilize the output VFO of the upstream O2 sensor to determine a feedback control factor .alpha. and is run at predetermined intervals (e.g. 4 ms) The first step of this routine is such as to determine if conditions (referred to as FRONT O2 F/B) which permit the use of the upstream side O2 sensor exist or not.
In the event that such conditions exist, for example: if the temperature of the engine coolant is not below a predetermined level of Tw; the engine is not being cranked/started; the engine has not just been started; the air-fuel mixture is not being deliberately enriched for engine warm-up; the output of the upstream O2 sensor has not yet switched from one level to another; or the engine is not undergoing a fuel cut, then it is deemed that conditions which enable the use of the sensor exist and the routine should flow to step S2. In this step the output OSR1 of the upstream O2 sensor is subject to A/D conversion, read and the value set in memory. In step S3 the instant value of OSR1 is compared with a slice level SLF (e.g. 0.45 volt) which is selected to represent, the air/fuel ratio. In the event that the outcome is such as to indicate that VFO.gtoreq.SLF (viz., lean) the routine goes to step S4 wherein a flag F1 is cleared (i.e. F1=0), while in the event that VFO>SLF the routine proceeds to step S5 wherein flag F1 is set (F1=1).
As will be appreciated flag F1 is such as to indicate if the air-fuel mixture is richer or leaner than stoichiometric value. F1=0=lean, F1=1 rich.
In steps S6 to S8 the status of F1 for this run is compared with that of the previous one in manner to establish four possible paths for the routine to follow to one of steps S9 to S12. In these latter mentioned four steps an air/fuel ratio feedback correction factor .alpha. is subject to the following methods of derivation:
(i) In the case the routine flows from S6.fwdarw.S7.fwdarw.S9 the air-fuel ratio is indicated as just having undergone a rich lean change and .alpha. is derived by incrementing the instant value by a proportional component PL (.alpha.=.alpha.+PL). This tends to incrementally enrich the air/fuel mixture and thus shift the air-fuel ratio stepwisely back toward the stoichiometric value. PA1 (ii) In the case the routine follows a S6.fwdarw.S7.fwdarw.S10 path, the air-fuel mixture is indicated as just having undergone a lean.fwdarw.rich change. Accordingly .alpha. is derived by decrementing the instant value by a proportional component PR (.alpha.=.alpha.- PR). This tends to stepwisely lean the mixture back from the rich side. PA1 (iii) In the case of a S6.fwdarw.S8.fwdarw.S11 flow, a previously lean condition is again detected and the value of .alpha. is derived by adding an integrated component IL. This induces the A/F to return gradually toward the rich side. PA1 (iv) In the event of a S6.fwdarw.S8.fwdarw.S11 flow, a previously rich condition is again detected and the value of .alpha. is derived by subtracting an integrated component IR. This induces the A/F to return gradually toward the lean side.
The flow chart shown in FIG. 24 depicts a routine which utilizes the output of the downstream O2 sensor for deriving an .alpha. correction. This routine is run at predetermined intervals of 512 ms (for example). The reason for this relatively long delay between runs is to ensure that the feedback control which is primarily based on the output of the upstream O2 sensor (which is highly responsive to the changes in A/F) is not dulled by overly frequent application of the output of the downstream O2 sensor which, due to its position downstream of the catalytic converter, is more remote and much less responsive to changes in the air-fuel mixture being combusted in the combustion chamber(s) of the engine.
At steps S21-S25 the status of the downstream O2 sensor is checked to determine if the output (REAR O2 F/B) can be used for feedback control purposes. The output of the downstream O2 sensor is deemed to be unsuitable for feedback control correction when the conditions which effect the upstream sensor are found to be unsuitable; when the engine coolant temperature is found to be less than Tw (in this case 70.degree. C.) step S22; when the engine throttle opening LL is is fully opened (LL=1) - step S23; when the engine load/engine speed ratio Qa/Ne<X1-step S24; or when in step S25 the downstream O2 sensor is found not to have been activated.
In the event that the appropriate requirements can be met, indicating that conditions wherein the output of the downstream 02 sensor can relied upon, the routine goes to step S26 wherein the output of the same VRO is A/D converted, read and set in memory. At step S27 the instant value of VRO is compared with a slice level SLR. In this instance the slice level is selected to represent the stoichiometric air-fuel ratio (e.g. 0.55 volt). In the event that it is found that the VRO.ltoreq.SLR the air-fuel mixture is deemed to be on the lean side and the routine flows to steps S28-S31. On the other hand, if VRO<SLR the mixture is indicated as being on the rich side and the routine is directed to steps S32 to S35.
It should be noted that as the slice level SLR is set a little higher than SLF due to the fact that gases upstream and downstream of the catalytic converter are different and induce the sensors to exhibit slightly different output characteristics and to also allow for the different degradation rates between the two sensors.
At step S28 the PL value is incremented by a fixed value .DELTA.P (Viz., .DELTA.PL (PL=PL+.DELTA.PL). At step S29 the value of PR is decremented by a fixed value .DELTA.PR (PR=PR-.DELTA.APR. This has the effect of shifting the overall A/F in the rich direction.
At step S30 a constant value .DELTA.IL is subtracted from the integrated component IL in order to reduce the amplitude at which .alpha. increases as a result of the increase of PL in step S28. At step S31, a constant value .DELTA.IR is added to the integrated component IR in order to reduce the delay with which the output of the upstream O2 sensor switches from rich to lean, it being noted that this delay is induced by the increase in the PR value in step S29.
When the A/F is indicated by the output of the upstream O2 sensor to be on the lean side, .alpha. correction control is implemented in steps S28 to S31.
FIG. 25 shows a routine which is run at predetermined crankshaft rotation angle intervals (e.g. 30.degree. CA)and which is used to derive the fuel injection pulse width Ti [ms]. The first step S41 is such as to derive the basic injection pulse width Tp by table look-up using data which is recorded in terms of engine speed and the engine load. Following this in step S42, the sum of a plurality of correction factors (e.g. engine temperature related correction factor KTW) is calculated and at step S43 the actual injection pulse width Ti is derived using the equation: EQU Ti=Tp.times.Co.times..alpha.+Ts (1)
where Ts denotes the rise time of the fuel injector(s).
In step S44 the derived value of Ti is set in memory and used to produce the appropriate injection pulse(s).
However, the above type of air-fuel ratio control is such that the proportional component values (Pr, PL) used therein are obtained from mapped data wherein, in order to prevent engine surging, the data which falls in a predetermined special zone, is required to exhibits a particularly fine resolution (viz., changes in small increments). On the other hand, in order to render the adaptive or self-updating control more dynamic, the resolution of the data in updating zones is reduced.
In the event that, as shown in FIG. 15, the special zone (cross hatched) is smaller than one of the four updating zones A-D, a problem is encountered in that as the special zone is located in zone D, in the case the data is read out of the special zone on one or more runs of the control program(s) and then is read out of the zone D' (the zone surrounding the special zone) a sudden change in the correction amount is apt to to be induced and result in the deterioration of the emission control. To overcome this, it is possible to increase the resolution of the updating data, however, this requires a larger amount of ROM area.
A further problem is encountered in that, as the special zone overlaps part of the updating or adaptive zone, the updating zone is reduced and thus reduces the chances (frequency) of the updating process being carried out.

Dual sensor type air fuel ratio control system for internal combustion engine


A pellet press machine, comprises a die block assembly for receiving powder to be compacted, and a press assembly for compacting the powder, the die block assembly laterally movable along a linear horizontal axis between the filling location at which an array of dies are filled with the powder to be pressed at the pressing location in which the powder in dies is pressed to form pellets. The filling assembly includes an auger driving by a motor to force the powder directly into dies. The auger further has a sharp edge sits right above the dies to force the powder directly into dies and the sharp edge scrapes the top surface of the dies so as to allow the high degree accuracy of filling dose for each die. With this filling assembly, the pellet press machine can product high density and small diameter pellet with high density and sticky density powder.

The present invention relates to a press system for forming shaped articles, e.g. pellets presses or tablets presses and more particularly, although not exclusively, to a press system for use in producing tablets or pellets, which could be used in pharmaceutical, nutritional, chemical and other industries.
The terminology of tablets or pellets in this application is not limited to the oral taking medicine, it also includes the pellets of small rod-shaped or ovoid mass, as of compressed steroid hormones, intended for subcutaneous implantation in body tissue to provide time release over an extended period of time (Source: The American Heritage Stedman's Medical Dictionary). These pellets are surgically inserted under the skin of patients and are time released over a period of time, eliminating the need to take medication orally, through injection or topically on a daily basis. Patients that require Hormone Replacement Therapy, Diabetics requiring insulin, or individuals that want vitamins and minerals will benefit from the use of these pellets. And therefore it is of great importance that our invention accomplishes the manufacture of these pellets in great accuracy and repeatability to ensure no harm is incurred by the individual. The small diameter, hardness, dissolution rate and friability to manufacture pellets can not achieved by the traditional tablet or pellets making machines.
Right now, the large-scale production of tablets or pellets typically involves the use of tablet punches which operate to compact a volume of powder filled in a die. The powder in the die is held between opposing punches which move together by a predetermined distance of travel to produce a tablet of controlled thickness within a die of known geometry. This is such that the formed tablet has a known or determinable density according to the die geometry and volume of powder used but there is no direct control of the force applied to the powder during the filling process.
It is because the pellets press machines in the prior art, such as US 2009/0130243 A1 or WO 2014/001805, rely on gravity feed only or a combination of gravity feed and fan feed blades to the dies. These methods of feeding do not allow the use of dense or sticky powders to be used. These powders will not flow downwards into the dies because they bind together and need an external force to force them into the dies. No downward force is produced by the fan blades and their purpose is to control the rate at which the dies are filled. To allow powders to flow in the prior art an excipient needs to be added, this can cause a change in powder formulation with undesirable results and therefore not allow new formulas or natural ingredients to be used as powder.
Even though a pellet molding apparatus, as in U.S. Pat. No. 4,317,649, have an auger filler to fill die holes. But because of the auger distance away from the die holes, the auger only acts as a switch to allow the flow of powder or stop the flow of powder. Gravity is still the force used in filling the die holes because the powder falls from the auger location down the tube then into the dies.
The prior art has a limitation of only filling large diameter of die size holes accurately. It is also because there is no force used for filling the dies, the hardness or accuracy of dose of the pellets can not meet the requirement to be used as a subcutaneous implantation in body tissue.
In view of the preceding, it would therefore be advantageous to have a press machine that can use dense and sticky powder to produce small diameter, hardness, dissolution rate pellets of outstanding accuracy, which can be surgically inserted under the skin of patients and be time released over a period of time.


A die stock comprising a holder, which is symmetrical to a centric holder longitudinal axis, wherein the holder has a plurality of receiving grooves each of which is configured for receiving a cutting insert and a clamping wedge, each of the receiving grooves extending from a first end face of the holder in the axial direction, the first end face running transversely to the axial direction, and wherein each of the receiving grooves extends from an inner side of the holder in a radial direction, the inner side facing toward the holder longitudinal axis. The die stock further comprises a plurality of cutting inserts, wherein each cutting insert has, on a front side that faces substantially toward the holder longitudinal axis, at least one cutting edge. The die stock further comprises a plurality of clamping wedges arranged detachably in the receiving grooves.

This disclosure relates to a die stock comprising a substantially cylindrical holder, which is symmetrical to a centric holder longitudinal axis that runs in an axial direction, and has a plurality of receiving grooves each of which is configured for receiving a cutting insert and a clamping wedge, wherein each of the receiving grooves extends from a first end face of the holder in the axial direction, said first end face running transversely to the axial direction, and wherein each of the receiving grooves extends from an inner side of the holder in a radial direction, said inner side facing toward the holder longitudinal axis, wherein a plurality of cutting inserts are provided that are arranged detachably in the receiving grooves, wherein each cutting insert has, on a front side that faces substantially toward the holder longitudinal axis, at least one cutting edge. This disclosure further relates to a holder and a cutting insert for such a die stock.
An exemplary die stock of this generic type is known from WO 2012/117033 A1.
Die stocks, often also referred to as screw dies, are frequently used for machining of external threads and are known in various embodiments. In one embodiment, the die stocks are realized in one piece as a HSS (High Speed Steel) tool. Although these are inexpensive to produce, they are limited in performance and uneconomical due to low cutting data. In addition, if a cutting edge is damaged, the entire die stock has to be exchanged.
Furthermore, die stocks which are made fully of hard metal as a one-piece tool are known. These provide a better performance, but are very expensive and complex in terms of production.
In addition, die stocks having exchangeable cutting inserts are known. These have in principle, however, fewer cutting inserts than the above-stated HSS die stocks and hard metal die stocks, owing to the fitting space conditions. Moreover, because of the necessary space for insertion of the cutting inserts, such die stocks generally provide unfavorable stability of the tool. Examples thereof are known from U.S. Pat. Nos. 2,174,467 A, 2,152,567 A and from GB 406,892 A. In these die stocks, the handling for exchange of the cutting inserts is relatively complex, however. Also the positioning of the individual cutting inserts relative to one another here appears to be quite complex. A further main problem consists in guaranteeing an optimally stable and exactly defined insert fit of the cutting inserts in the die stock holder. In the last-named examples, however, this cannot be assumed.

HARTMETALL-WERKZEUGFABRIK PAUL HORN GMBH


A nonvolatile storage cell and an integrated circuit (IC) including the cells. A layered spacer (ONO) is formed at least at one sidewall of cell gates. Source/drain diffusions at each layered spacer underlap the adjacent gate. Charge may be stored at a layer (an imbedded nitride layer) in the layered spacer.

Nonvolatile floating gate storage devices, such as may be used for memory cells in a nonvolatile random access memory (NVRAM), are well known in the industry. In a typical such NVRAM cell, the cell's conductive state is determined by charge or lack thereof on the storage device's floating gate. The floating gate is an electrically isolated gate of a field effect transistor (FET) stacked in a two device NAND-like structure with the gate of a select device. Charge is forced onto or removed from the floating gate through a thin insulator layer that, during a normal read, isolates the gate electrically from other adjoining conductive layers. For example, a negatively (or positively) charged floating gate may be representative of a binary one state, while an uncharged floating gate may be representative of a binary zero state or, vice versa.
Typically, the select device in the NAND-like structure is connected to a word line. In typical state of the art designs, adjacent cells are connected to a common bit line. Each of the word lines is uniquely addressable and physically distinct. Intersection of each word line with each bit line provides unique cell selection for reading and writing the selected cell. For reading, a read voltage (e.g., Vhi or ground) is applied to a control gate (or program gate) that is capacitively coupled to floating gates of the nonvolatile devices of devices being read. Typically, the bit lines are pre-charged high. Thus, when a word line is raised, bit lines discharge for those devices programmed for zeros and do not those programmed for ones. For writing, a write voltage applied to the control gate (or program gate) is capacitively coupled to floating gates of the nonvolatile devices and, when the gate, source and drain voltages are biased properly, the charge changes on the floating gate, i.e., to write selected cells. Similarly, cells are biased to remove the charge from the floating gates during each erase.
The typically high voltages needed to write and erase each cell normally require a very complicated fabrication process. So, to minimize cell write voltages and for adequate read performance, the floating gate is large. Consequently, large floating gates account for much of the cell area for a typical NVRAM cell. While, reduced cell size cannot come at the expense of unacceptably degraded performance, designers normally strive for minimum cell size to achieve maximum cell density for reduced storage costs.
Thus, there is a need for smaller, denser NVRAM cells.

Eraseable nonvolatile memory with sidewall storage

International Business Machines Corporation


The invention relates to an apparatus for hot-pressing a planar product in a process using microwave heating. The apparatus comprises a constant-volume, box-like microwave resonant cavity divided into two opposed subcavities by an elongated gap suitable for passing therethrough the product (1) to be heated. The product is guided through the gap by conveyor belts (2, 2xe2x80x2) of microwave-transparent material. The subcavities are delineated from the conveyor passageway gap by parallel walls of microwave-transparent material, each one of them sealed so as to form a wall of its own subcavity. At least one of the subcavities is pressurized, whereby the sealed wall of the pressurized subcavity is designed to yield under the pressure applied into the subcavity in a direction perpendicular to the product (1) to be pressed.

The invention relates to an apparatus for hot-pressing a planar product in a process using microwave heating.
Heating of planar wood products containing glue layers up to the curing temperature of the glue using microwave heating is known in the art. Apparatuses based on this heating technique have the heating unit formed into a box-like resonant cavity via which the product to be heated is passed. The product is passed via a narrow gap that extends lengthwise through the entire cavity and in which gap the product travels conventionally supported by conveyor belts. The material of the belts is selected to be transparent to microwave radiation.
After the heating step, the product is generally passed to a press apparatus, wherein the throughout heated product is pressed to its target thickness and the glue is cured by the latent heat of the product.
Conventional processes have rarely used pressing during the heating step due to the limitations set by the basic construction of the microwave heating system. Microwave energy must be contained in a resonant cavity through which the product being heated is passed. To establish resonant conditions in the cavity, its walls must be spaced at a given distance from each other. This constraint excludes the possibility of moving the parts of the resonant chamber in regard to each other in order to accomplish the pressing step. A certain degree of compressive pressure has been imposed in the prior art on the product during the heating step by way of arranging press rolls on the opposite side of the conveyor belts traveling through the resonant cavity such that the rolls have been able to press the conveyor belts against the product being heated. This embodiment, however, is limited by the belt material durability as to the maximum applicable pressure and, moreover, to the uniform distribution of the pressure imposed over the product surface. The belt material must be selected transparent to microwaves, whereby the use of metallic belts for instance is excluded.
Now, an improvement according to the invention is offered to ovecome such problems by virtue of an apparatus comprising in a conventional fashion a constant-volume, box-like microwave resonant cavity suitable for division into two opposed subcavities by an elongated gap suitable for passing therethrough the product to be heated and conveyor belts of microwave-transparent material for guiding the product to be heated through the gap, whereby the subcavities are delineated from the conveyor passageway gap by parallel walls of microwave-transparent material, each one of them sealed so as to form a wall of its own subcavity, of which subcavities at least one is pressurized and that the sealed wall of the at least one pressurized subcavity is designed to yield under the pressure applied into the subcavity in a direction perpendicular to the product to be pressed.
Such pressurization of at least one of the opposed subcavities of the resonant cavity makes it possible to apply to the conveyor belts a moderate, uniformly distributed pressing force that allows the product to be pressed in a desired fashion already during the heating step of the product.
Next, the invention will be examined in greater detail by making reference to the appended drawing, wherein an apparatus according to the invention is shown in a sectional side elevation view.

Apparatus for hot-pressing a planar product


A laminate film has a clear layer (B) comprising an acrylic-based polymer (B1) having at least one longer unsaturated double bond group and at least one shorter unsaturated double bond group as side chains, and having a weight-average molecular weight not less than 50,000 but not more than 500,000, the longer unsaturated double bond group introduced in the acrylic-based polymer (B1) by a long-chain unsaturated carboxylic acid having a molecular weight of 150 or more, and the shorter unsaturated double bond group introduced in the acrylic-based polymer (B1) by a short-chain unsaturated carboxylic acid having a molecular weight of less than 150. Compared with laminate films prepared by spray coating, dip coating, or other coating methods, this laminate film is excellent in processability, coating film properties, and ornamental properties. Thus, an article can be excellently decorated with the laminate film provided by the present invention.

For articles (examples of the articles encompasses shaped products (i.e. products having been processed to have desired shapes) such as metal products, plastic products, inorganic products, wood products and the like), coating (painting) process to form a coating film on the articles (shaped products) is carried out in some cases, in order to give the article durability and/or aesthetic property including hues. The articles to be coated (hereinafter, referred to as coating-target articles) are various in terms of their materials, shapes and the like. In view of this, spray coating, dip coating and other coating method are widely used because it is relatively easy by using these methods to form the coating film in accordance with complicate shapes of the coating-target article, and to form the coating film in bag-shaped sections (cave-shaped sections) and/or gaps of the coating-target article.
In general, the coating film formed by coating (painting) the coating-target article is laminate film including a plurality of layers. For instance, the laminate film includes (a) a base film for giving the laminate film adhesiveness and anticorrosiveness so as to allow the laminate film to be adhered on a surface of the coating-target article and to protect the coating-target article from being corroded, (b) a finish-coat film for giving the coating-target article aesthetic appearance, (c) a protective film for protecting the finish-coat film, and/or (d) the like layer. Therefore, in case where the spray coating or the dip coating is applied, a step (coating step) of coating the coating-target article with paint by spraying the paint onto the coating-target article or dipping the coating-target article in the paint, and a step (fixing step) of fixing the paint on the coating-target article by drying or baking are repeated in turn in order to form the respective films of the laminate film.
The spray coating and the dip coating, which are multi-staged process in which the coating step and the fixing step are repeated in turn require a large coating site in which a long process line is constructed for the multi-staged process. Moreover, because the coating step and the fixing step are carried out in multi stages, the process management is complicate. Further, the multi-stage process causes a large consumption of a volatile material in the coating step and the fixing step, and requires a large amount of energy to repeat the coating step and the fixing step.
Therefore, it is difficult to solve or achieve the followings problems or required improvement in the coating process using the spray coating or the dip coating. The problems and improvements are: need of securing the coating site; need of improving cost performance by reducing maintenance cost for coating and drying, alleviating smell of the volatile material, and reducing a volatilized amount of the volatile material, and the like improvement; need of attaining easy management for the coating process; need of reducing the energy consumption; and the like needs.
As a coating method for realizing the improvement in cost performance, easy management of the coating process and the lower energy consumption, Publications of Japanese Patent Applications, publication Nos. 2000-79796 (Tokukai 2000-79796; published Mar. 21, 2000), and 10-58895 (Tokukaihei 10-58895; published on Mar. 3, 1998) and the like publication, for example, teach so-called film decoration method in which the coating-target article is coated with a laminate film which comprises a plurality of layers in lamination. In the film decoration method, the laminate film is placed on the surface of the coating-target article with no space therebetween so as to coat the coating-target article. Therefore, the film decoration method requires no multi staged coating process unlike the spray coating, dip coating and the like coating methods. Moreover, the process of the film decoration method is easy to manage and has lower energy consumption.
Meanwhile, it is required for the laminate film that it have properties (hardness, non-stickiness, solvent resistance, chemical resistance and other properties; hereinafter referred to as "coating film properties) realized in the spray coating, dip coating, and like, and that it have ornamental property (property to give the coating-target article a decorative appearance) and processability (property to enable appropriate decoration of the coating-target article). Here, the ornamental property includes: a shining appearance that indicates how shiny (twinkling) the laminate film is when the coating-target article is decorated with the laminate film; light scattering property of the laminate film when the coating-target article is decorated with the laminate film; flip-flop property that indicates a contrast between a highlighted look and a shaded look of the laminate film when the coating-target article is decorated with the laminate film; and other property. Moreover, the processability includes: traceability (shape-tracing ability) for a shape of the coating-target article; reproducibility for the 3-dimentional shape of the coating-target article; easy handling such as easiness in winding the laminate film; and other property.
However, the conventional laminate film has a difficulty to attain the processability and ornamental property as well as the coating film properties: the conventional film with high coating film properties is poor in the processability and ornamental property: likewise, the conventional film with high processability has a problem in the coating film properties and the ornamental property.
More specifically speaking, if the processability of the laminate film is to be improved, it is necessary to give the laminate film flexibility so that the laminate film can trace the shape of the shaped product (coating-target article). The flexibility can be attained by preparing the laminate film with a resin having a low glass transition temperature, by reducing the cross-linking density of the laminate film, or by the like.
However, if the laminate film is improved in flexibility, it becomes difficult to attain the coating film properties of the laminate film. Moreover, it becomes easy to disorder an array of a light scattering material or the like that gives the laminate film twinkling sensation and flip-flop property. Thus, it becomes difficult to attain the ornamental property.
As described above, there are such problems for the conventional film decoration method that when the processability necessary for decorating the coating-target article with the laminate film is attained, it is difficult to attain the coating film properties and the ornamental property equivalent to these attained in the spray coating, dip coating, and other coating methods.


A scleral lens is provided with a sodium channel blocker or a sodium channel modulator disposed in the pre-corneal tear film between the scleral lens and the cornea. This system can be used to deliver sodium channel blockers or a sodium channel modulators not currently used because of poor bioavailability. Methods of using this sodium channel blocker delivery system or a sodium channel modulator delivery system are also disclosed.

Eye diseases and conditions can be treated with topical agents, such as drops or ointments, which use direct absorption to reach therapeutic drug levels at the target tissue. Topical application is especially useful for the cornea, which has virtually no blood supply and is easily accessible for topical application. When drugs are applied topically in the form of drops or ointment to the cornea, however, the drug solution rapidly disperses into the tear film and flows into the tear drainage system, thereby reducing bioavailability. Non-limiting examples of factors affecting the bioavailability of a drug (i.e., drug levels) in the cornea and to the anterior chamber of the eye include the duration of the drug's effective concentration at the surface of the cornea, and the drug's ability to be absorbed into the corneal tissue.
Delivering medications in the form of eye drops can have two main disadvantages. First, the concentration of the drug can rapidly fall below therapeutic levels, potentially requiring frequent applications of the drug. Second, high concentrations of the drug may be necessary to achieve adequate penetration into the eye because of the drug's brief contact time with the eye, and these high concentrations may be toxic.
An existing method of delivering a drug to the cornea involves dehydrating a soft contact lens, then soaking the lens in a solution of the drug. This method provides an initial burst release of the drug followed by continuous decline in the amount of drug at the cornea. This leads to limited bioavailability of the drug after the initial burst release.
Another method of delivering a drug to the cornea involves soaking a collagen shield in a solution of the drug. These collagen shields are opaque and must be worn in a recess under the lids. Because the impregnated drug is carried to the corneal surface by the tears, its bioavailability is limited in dry eye disease, a common condition in eyes with neuropathic pain.

This patent is subject to a terminal disclaimer.

Sodium channel blocker delivery system with scleral lens


An integral valve stem seal retainer and spring seat for a reduced diameter valve seal subassembly is disclosed having lower and upper portions. An annular sealing member is bonded to the upper portion of the metal retainer and an annular flange extends radially outwardly of the lower portion of the retainer to engage at least one coil of a reduced diameter valve spring. The annular sealing member further includes upper and lower portions, wherein the upper portion engages an outer surface of a valve stem while the lower portion engages a top of a thin-wall valve guide.

In conventional overhead valve internal combustion engines, at least two valves reciprocate to provide intermittent communication between intake and exhaust manifolds and a combustion chamber. The valves include valve stems that are commonly disposed in valve stem guides, supporting axial motion in an engine component such as an engine head. Lubrication is provided to upper portions of the valve stems by a spray of lubricating oil within a valve cover disposed over the engine head or by gravity flow from an associated rocker arm. Oil flows along a free upper end of the valve stem toward the manifolds and valve heads by the force of gravity and may be encouraged by a pressure differential in the manifold versus crankcase pressure.
Annular valve stem seals are generally urged into contact with the outer surface of the valve stem and an upper portion of the valve guide by a valve stem seal retainer, and serve various purposes. First, valve stem seals minimize engine oil consumption by restricting oil entry into the manifold and the combustion chamber. Second, they help to minimize exhaust particulates that contribute to pollution. Third, they are helpful in minimizing guide wear, which is of particular importance in large diesel engines due to the nature of their operation. The valve stem, valve guide, and valve stem seals are annularly wrapped by a helical compression valve spring that serves to bias the valve into a closed position. The longitudinal ends of the valve spring are restrained by flanges on corresponding valve spring retainers and/or spring seats, thereby maintaining proper alignment and position of the valve and valve spring.
In the heavy-duty engine market a number of changes are being made to comply with recent and prospective emissions standards. As the construction of the engine changes, engine designers must nevertheless maintain a robust engine design with a sufficient level of dependability. One of the more prominent changes being implemented is the increase of the power rating of the engine in an effort to reduce the size of the engine. In particular, engine manufacturers are attempting to reduce the displacement of heavy-duty engines while still providing ample horsepower and torque for heavy-duty applications. As is well-known, engine displacement is calculated by multiplying cylinder bore area times the piston stroke length. In reducing the displacement of heavy-duty engines, manufacturers are reducing both the bore area and the stroke length while increasing the compression within the combustion chamber. Increasing the required amount of compression, in turn, places greater stress on the valve seal. Many of these engines are increasing their compression by up to 50-60 psig, which is a far greater pressure than many prior art valve seals can handle while being properly retained on a valve guide. For such cases, an integral valve seal with a metal retainer is normally recommended.
However, as the bore area of an engine is reduced, the area provided for valve assemblies above a combustion chamber is correspondingly reduced. The problem is especially significant in heavy-duty diesel engines because all valve assemblies are typically oriented perpendicular to the engine head. Additionally, a fuel injector occupies a large portion of the area above the cylinder bore. Thus, in high efficiency heavy-duty diesel engines having more than two valves (intake and exhaust valves) per cylinder, the area directly above the engine bore must be shared by a fuel injector and the valves. Since the size of the fuel injector is substantially fixed, a reduction in engine bore generally requires a reduction in the valve assembly diameter, including corresponding reductions in the diameter of valve stem seals, valve guides, and valve stem seal retainers. There is thus a need for a valve seal assembly capable of withstanding increased compression loads while providing a seal having close clearance and durability.


A loudspeaker unit for producing sound at bass frequencies an array of two or more diaphragms. The first radiating surface and the second radiating surface are located on opposite faces of the diaphragm, and one or more of the diaphragms are included in a first subset of the diaphragms and one or more of the diaphragms are included in a second subset of the diaphragms; a plurality of drive units.

Among the frequencies in the audible spectrum, lower frequencies are the ones that tend to carry most well over larger distances and are the ones difficult to keep inside a room. For example, nuisance from neighboring loud music has mostly a low frequency spectrum. "Low" frequencies can also be referred to as "bass" frequencies and these terms may be used interchangeably throughout this document.
Many cars today are equipped with a main audio system, which typically consist of a central user interface console with internal or external audio amplifiers, and one or more loudspeakers placed in the doors. This type of audio systems is used to ensure enough loudness of the same content (e.g. radio or cd-playback) for all passengers.
Some cars include personal entertainment systems (music, games & television) which are typically equipped with headphones to ensure individual passengers receive personalized sound, without disturbing (or being disturbed by) other passengers who are enjoining a different audio-visual content.
Some cars include loudspeakers placed very close to an individual passenger, so that sound having an adequately high sound pressure level ("SPL") can be obtained at the ears of that individual passenger, whilst having a much lower SPL at the positions of other passengers.
The present inventor has observed that the concept of a personal sound cocoon is a useful way to understand the approach of having a loudspeaker placed close to a user, wherein the personal sound cocoon is a region in which a user is able to experience sound having an SPL deemed to be acceptably high for their enjoyment, whereas outside the personal sound cocoon the sound is deemed to have an SPL which is lower than it is within the personal sound cocoon.
The present inventor has also observed that creating a personal sound cocoon that can be enjoyed by the user with little sound leakage into his/her surroundings is a big challenge that if overcome could bring a huge change in how users experience our individual multimedia content in all kind of settings/surroundings such as (but not limited) to automotive, home, gaming, and aviation settings.
The present inventor has also observed that creating an effective personal sound cocoon may involve sound reduction or cancellation of sound outside of the cocoon.
A main audio system as used in most cars today (with one or more loudspeakers placed in the doors) is unable to provide an effective personal sound cocoon for each individual passenger.
Although the usage of headphones ensures a good sound quality and a very effective personal sound cocoon (little sound leakage), the use of headphones has safety, ergonomic and comfort problems. Similar considerations apply for standalone applications in other environments such as home, studio, public areas where individual entertainment is needed without disturbing neighbors.
The use of highly directive loudspeakers positioned close to an individual passenger/user brings an effective solution for medium and high frequencies. However, it is generally impractical in most situations to make a loudspeaker directive at bass frequencies, since in order to provide a highly directive loudspeaker for bass frequencies, the dimensions of the radiating surface must be of the same order as the wavelength, and wavelengths are typically very long for bass frequency content (e.g. λ=3.4 m for f=100 Hz). Loudspeakers with radiating surfaces of this scale for producing bass frequency content are impractical in many situations, such as in a car. Nonetheless, bass frequency content is a very important part of the audio spectrum and in most music this spectrum represents half or more of the total sound power.
As shown by the well-known equal-loudness contours [1] e.g. as standardized as ISO 226:2003, our ears have a low sensitivity to bass frequencies under 150 Hz. Therefore, in general, sound at bass frequencies needs to be boosted in order to balance the spectral loudness. Also, road noise or environmental noise will have a bigger masking effect on this part of the spectrum. However, the present inventor has found that the use of traditional monopole loudspeakers (typically a cone monopole loudspeaker) for the purpose of creating a personal sound cocoon for an individual user at bass frequency sound will in general not produce satisfactory results, since a relatively high SPL at bass frequencies is needed in order to create a personal sound cocoon to overcome the limited sensitivity of our ears in this region of the frequency spectrum, yet a traditional monopole loudspeaker will have a spherical radiation pattern at bass frequencies (same sound pressure in all directions), with its sound pressure dropping only with 6 dB for every double distance from the loudspeaker under free field conditions. Further, a car environment behaves not as a free field, making the use of monopole loudspeakers for bass frequency cocooning even more cumbersome: a small room will show a pressure chamber effect whereby it will boost the bass frequency energy provided by a monopole (overall pressure increases in the chamber of 12 dB/octave below 70 Hz for a typical car).
The present inventor is aware of several patent documents which describe using a variety of loudspeaker arrangements for the purpose of producing personal sound in vehicles:                EP0988771A1        EP1460879A1        U.S. Pat. No. 8,130,987B2        U.S. Pat. No. 7,688,992B2        U.S. Pat. No. 9,327,628B2        U.S. Pat. No. 9,440,566B2        U.S. Pat. No. 9,428,090B2
The present inventor is also aware of other loudspeaker arrangements for producing personal sound in other contexts:                WO2014143927A2        U.S. Pat. No. 7,692,363B2
Dipole loudspeakers and their directional characteristics are well described in the literature and some of the patent documents referenced above use dipole loudspeakers, mostly for the purpose of using the directional characteristics of a dipole loudspeaker to generate spatial effects in the mid and high frequency region, or to use a dipole loudspeaker for low frequency reproduction at large distances, e.g. normal stereo setup, see e.g. [2] for useful background information on this.
In pending PCT application PCT/EP2018/084636, as well as in GB patent application nos. GB1721127.7 and GB1805525.1 (to which PCT/EP2018/084636 claims priority), filed by the present applicant, there is proposed a dipole loudspeaker for producing sound at bass frequencies, the dipole loudspeaker including: a diaphragm having a first radiating surface and a second radiating surface, wherein the first radiating surface and the second radiating surface are located on opposite faces of the diaphragm, and wherein the first and second radiating surfaces each have a surface area of at least 100 cm2; a drive unit configured to move the diaphragm at bass frequencies such that the first and second radiating surfaces produce sound at bass frequencies, wherein the sound produced by the first radiating surface is in antiphase with sound produced by the second radiating surface; a frame, wherein the diaphragm is suspended from the frame via one or more suspension elements, wherein the frame is configured to allow sound produced by the first radiating surface to propagate out from a first side of the dipole loudspeaker and to allow sound produced by the second radiating surface to propagate out from a second side of the dipole loudspeaker; wherein preferably the loudspeaker is for use with an ear of a user being located at a listening position that is in front of the first radiating surface and is 40 cm or less from the first radiating surface.
The invention described in PCT/EP2018/084636, GB1721127.7 and GB1805525.1 was based on an insight that for a suitably dimensioned diaphragm, from a listening position that is close to (e.g. 40 cm or less from) the first radiating surface of such a loudspeaker, a user can experience bass sound (typically up to 100 Hz) that is highly localized, in the sense that the sound pressure level (SPL) experienced by a user will quickly decrease with increasing distance from the loudspeaker.
The present inventor has observed that a loudspeaker made according to the teaching of PCT/EP2018/084636, GB1721127.7 and GB1805525.1 only provides an effective personal sound cocoon up to a certain upper frequency limit, which (depending on the performance of the personal sound cocoon desired may e.g. be 100 Hz or 160 Hz).
The present inventor has observed that it may be desirable to increase this upper frequency limit, and/or to improve the performance of the personal sound cocoon up to the same upper frequency limit
The present invention has been devised in light of the above considerations.


A blast tube includes three portions and three diaphragms. The first portion has a first length and a first cross section. The second portion has a second length and a second cross section. The third portion has a third length and a third cross section. The first diaphragm is disposed between the second portion and the third portion and switches from a closed state to an open state at a first time. The second diaphragm switches from a closed state to an open state at a second time after the first time. The third diaphragm is disposed between the first portion and the second portion and switches from a closed state to an open state at a third time after the second time. The third portion is disposed between the first diaphragm and the second diaphragm.

1. Field of the Invention
Example embodiments of the present invention generally relate to shock tube devices and, more particularly, to shock tube devices that generate multiple, e.g., primary and secondary, shock waves.
2. Description of the Related Art
Shock tube assemblies are used to simulate static and dynamic pressure conditions resulting from large energy blasts. These large energy blasts may be the result of conventional explosive detonation or nuclear detonation, for example. By simulating the conditions of such blasts without an actual full scale detonation, it is possible to evaluate the effects of such blasts on various types of equipment ranging from relatively small test articles, such radios, to relatively large test articles, such as full-size operational shelters, vehicles, tanks and aircraft. In effect, the shock tube assembly is a specialized short duration wind tunnel used for test and evaluation of various structures. Typically, a shock tube assembly includes various sections, such as a driver section containing a pressurized gas which is ultimately used to create the shock wave, a diaphragm section to suddenly release the driver gas, an expansion nozzle section to port the driver gas into a test chamber, along with associated gas processing and support equipment. The test article to be tested is placed in the test section. The driver is normally a hollow cylindrical pressure vessel with one end closed and sealed at the other end by the diaphragm section and capable of holding room temperature or elevated temperature gas at substantial pressure. The diaphragm section, associated with the driver, includes one or more diaphragms which are ruptured to release the gas in the driver, i.e., the shock tube diaphragm is mechanically, explosively or pressure ruptured to suddenly release the gas from the driver. In a dual diaphragm system, only one diaphragm is ruptured and the higher pressure differential imposed on the second diaphragm bursts it to release the gas. From the diaphragm section, the gas flows through the expander nozzle section, the discharge end of which is located within the expansion tube. The gas flowing through the nozzle section is supersonically expanded within the expansion chamber to create a shock wave which travels down the elongated expansion tube, compressing the air behind the travelling shock wave interface thereby providing both the static and dynamic pressure conditions and temperature conditions for testing and evaluating the test article located within the expansion tube and which is exposed to the static and dynamic pressure generated by the shockwave.
As mentioned above, the structure of classical and currently utilized blast tube is composed of a high pressure tubular section and a low pressure tubular section separated by a diaphragm. A diaphragm is a device, typically surface, that can change from a first state to a second state. In the first state, or closed state, the diaphragm acts as a barrier between the high pressure tubular section and the low pressure tubular section. In the second state, or open state, the diaphragm allows mixing between the high pressure tubular section and the low pressure tubular section.
The effectiveness of the shockwave is dependent on how rapidly and completely the designed system can switch from an open state to a closed state. The quicker that the diaphragm can switch to an open state is directly correlated to the characteristics and reproducibility of a shockwave.
Current, compressed-air driven blast tubes usually use one or two single or double diaphragms, which are placed between the high pressure and low pressure sections. In this configuration, blast tubes are only capable of generating single shock waves. Current blast tubes are not capable of reproducing multiple shock waves nor are they able to modify blast wave characteristics such as shape, duration, or peak.
Another type of blast tube system that is currently in operation utilizes explosives to generate blast waves. The choice and availability of explosives is a significant limit when it comes to broader research applications. Blast tube systems that utilize explosives for shock wave generation need complex and sophisticated control systems. These types of shock tubes also are subject to stringent safety measures.
There are several blast tubes, such as the ones at the University of Central Florida, City College of New York, and the Aerospace Corporation in EI Segundo, Calif., but these existing shock tubes are only able to reproduce non-ideal blast conditions. More particularly, existing blast tubes lack the ability to replicate multiple shock waves.
Operation of one type of conventional blast tube system will now be described with reference to FIGS. 1-2.
FIG. 1 illustrates a conventional blast tube system 100.
As illustrated in the figure, system 100 includes a tube section 102, a tube section 104, a test chamber 106, a diaphragm 108, a diaphragm 110, a detector 112, an inlet valve 114, an inlet valve 116, an outlet valve 118, an outlet valve 120, a compressor 122 and a controller 124.
Tube section 102 has an end wall 126 and an open end 128. Tube section 104 has an open end 130 and another open end 132. Test chamber 106 has an open end 134 and an end 136 that can be open or closed. Test chamber 106 contains detector 112 positioned at end 136.
Tube section 102 is arranged such that open end 128 is adjacent to open end 130 of tube section 104. Further, test chamber 106 is arranged such that open end 134 is adjacent to open end 132 of tube section 104. Detector 112 is disposed at closed end 136 of test chamber 106.
Compressor 122 is arranged to receive compressor control signal 138 from controller 124.
Inlet valve 114 is arranged to receive a fluid through fluid line 148 from compressor 122. Additionally, inlet valve 114 is arranged to receive inlet valve control signal 140 from controller 124. Inlet valve 116 is arranged to receive a fluid through fluid line 150 from compressor 122. Additionally, inlet valve 116 is arranged to receive inlet valve control signal 142 from controller 124. Outlet valve 118 is arranged to receive outlet valve control signal 144 from controller 124. Outlet valve 120 is arranged to receive outlet valve control signal 146 from controller 124.
Tube section 102 and tube section 104 are able to receive and store a fluid at a predetermined temperature, pressure, and volume. Tube section 102 and tube section 104 may be any known device or system that is able to receive and store a fluid at a predetermined temperature, pressure, and volume. Non-limiting examples of tube section 102 and tube section 104 include pipes, drums and containers.
Test chamber 106 is able to contain a shockwave and expansion of fluid created in tube section 102 and tube section 104. Test chamber 106 may be any known device or system that will allow the expansion of a fluid to propagate through itself. Non-limiting examples of test chamber 106 include a closed pipe, open end pipe and chamber.
Diaphragm 108 acts as a controllable barrier between tube section 102 and tube section 104. In a first state, or closed state, diaphragm 108 prevents the mixing of fluids from tube section 102 and tube section 104. In a second state, or open state, diaphragm 108 is open and allows the flow of fluid from tube section 102 into tube section 104, creating a primary shockwave.
Diaphragm 110 acts as a controllable barrier between tube section 104 and test chamber 106. In a first state, or closed state, diaphragm 110 prevents the passage of fluid from tube section 104 into test chamber 106. In a second state, or open state, diaphragm 110 is open and allows a shock wave and fluid from tube section 102 and tube section 104 to propagate into test chamber 106.
Diaphragm 108 and diaphragm 110 may be any known devices or system that is operable to be closed in a first state and open in a second state. Non-limiting examples of diaphragm 108 and diaphragm 110 include a thin membrane, valve and scored plate.
Detector 112 detects the pressure inside of test chamber 106. Detector 112 may be any known device or system that is able to detect pressure inside of test chamber 106. Non-limiting examples of detector 112 include a barometer and a piezoelectric sensor.
Inlet valve 114 allows fluid to flow from compressor 122, by way of fluid line 148, into tube section 102. Inlet valve 114 is controlled by controller 124 through inlet valve control signal 140. Inlet valve 116 allows fluid to flow from compressor 122, by way of fluid line 150, into tube section 104. Inlet valve 116 is controlled by controller 124 through inlet valve control signal 142.
Inlet valve 114 and inlet valve 116 may be any known device or system that allows unidirectional fluid flow from compressor 122. Non-limiting examples of inlet valve 114 and inlet valve 116 include a globe valve, gate valve or needle valve.
Outlet valve 118 allows the flow of fluid out of tube section 102. Outlet valve 118 is controlled by controller 124 by outlet valve control signal 144. Outlet valve 120 allows the flow of fluid out of tube section 104. Outlet valve 120 is controlled by controller 124 through outlet valve control signal 146.
Outlet valve 118 and outlet valve 120 may be any known device or system that allows unidirectional fluid flow from tube section 102 and tube section 104. Non-limiting examples of outlet valve 118 and outlet valve 120 include a globe valve, gate valve and needle valve.
Compressor 122 provides a fluid under a controlled flow rate and/or pressure to inlet valve 114. Additionally, compressor 122 provides a fluid under a controlled flow rate and/or pressure to inlet valve 116. Compressor 122 IS controlled by controller 124 through compressor control signal 138.
Compressor 122 may be any known device or system that is able to provide a fluid under a controlled flow rate and/or pressure to inlet valve 114 and inlet valve 116. Non-limiting examples of compressor 122 include a centrifugal compressor, mixed flow compressor or axial flow compressor.
Controller 124 may be any known device or system that is able to control compressor 122, inlet valve 114, inlet valve 116, outlet valve 118, outlet valve 120, and detector 112. Non-limiting examples of controller 124 include a computer and a server.
In operation, system 100 is used to generate a controlled blast for study. Initial parameters are set for a particular test. The starting temperature and pressure in each of tube section 102 and tube section 104 are predetermined in order to study a resulting blast. To achieve the starting temperature and pressure, a user inputs the associated predetermined fluid temperature, pressure and volume into controller 124 through a user interface (not shown). With temperature, pressure, and volume known, controller 124 can send compressor control signal 138 to compressor 122. Compressor control signal 138 will instruct compressor 122 to begin pumping fluid into tube section 102 and tube section 104.
Fluid is pumped at a predetermined flow rate and/or pressure to inlet valve 114 and inlet valve 116. Fluid is unable to pass through inlet valve 114 and inlet valve 116 until they are opened by controller 124, via inlet valve control signal 148 and inlet valve control signal 150.
Once inlet valve 114 and inlet valve 116 are open, fluid is pumped into tube section 102 and tube section 104, by compressor 122. When controller 124 has calculated that the amounts of fluid in tube section 102 and tube section 104 have reached the predetermined temperature, pressure, and volume limits, it sends compressor control signal 138 to indicate compressor 122 should shut down.
Simultaneously, controller 124 sends inlet valve control signal 148 to inlet valve 114 and inlet valve control signal 150 to inlet valve 116 indicating that they should close to prevent the flow of fluid into tube section 102 and tube section 104.
Once fluid in tube section 102 and tube section 104 reaches a predetermined temperature, pressure, and volume, a user may enter time variables into controller 124 through a user interface. In some embodiments, time variables may be preset. The time variables are used to control the opening of diaphragm 108 and diaphragm 110.
There are several methods of opening a diaphragm in a blast tube system. One example method of opening a diaphragm is to have the diaphragm electrically actuated. In this method when the diaphragm receives a signal, it will open through electro-mechanical means. Another example method of opening a diaphragm is to have a diaphragm with a set pressure tolerance, and when the pressure tolerance is exceeded, the diaphragm ruptures allowing fluid to flow from tube section 102 to tube section 104. Another example method of opening a diaphragm is to have a diaphragm with a set temperature tolerance, and when the temperature tolerance is exceeded, the diaphragm ruptures allowing fluid to flow from tube section 102 into tube section 104.
Any of the above mentioned diaphragm control methods may be used individually or in conjunction with one another to achieve precise diaphragm timing.
For purposes of discussion, in this example embodiment, diaphragm 108 is electrically actuated, wherein control signal 152 will provide a voltage as to open diaphragm 108. Also in this example embodiment, diaphragm 110 is electrically actuated, wherein control signal 154 will provide a voltage as to open diaphragm 110.
At time t1, controller 124 will send diaphragm control signal 152 to diaphragm 108 indicating that it should switch from a closed state to an open state. When diaphragm 108 is switched to an open state, the temperature and pressure differential between tube section 102 and tube section 104 will facilitate the generation of a shockwave. The resultant shockwave will propagate from tube section 102 and tube section 104 towards test chamber 106.
At time t2, controller 124 will send diaphragm control signal 154 to diaphragm 110 indicating that it should switch from a closed state to an open state. This state change will allow the shockwave to propagate into test chamber 106. When the shock wave reaches test chamber 106, detector 112 will measure the pressure and temperature differentials that are created.
The detector will continue to measure temperature and pressure inside of test chamber 106 until the fluid reaches a state of equilibrium. Once the fluid has reached a state of equilibrium controller 124 will send outlet valve control signal 144 to outlet valve 118 and outlet valve control signal 146 to outlet valve 120. This will indicate that outlet valve 118 and outlet valve 120 should switch from a closed state to an open state. When outlet valve 118 and outlet valve 120 are open, fluid can be vented out of shock tube system 100.
FIG. 2 is a graph that illustrates the pressure at detector 112 inside of the shock tube system 100 described in FIG. 1 as a function of time.
As illustrated in FIG. 2, graph 200 includes a y-axis 202, an x-axis 204, and a function 206. Function 206 includes a function segment 208, a function segment 210, and a function segment 212. Y-axis 202 is pressure measured by detector 112 in Torr, whereas x-axis 204 is time in milliseconds.
Function segment 208 has a constant pressure p0 from time t0 to time t1. Function segment 210 has a maximum pressure p1 from time t1 to time t2. Function segment 212 decreases from pressure p1 to pressure p0 from time t2 to time t3.
In operation, at time t0 diaphragm 108 is in a closed state and acts as a barrier between tube section 102 and tube section 104. Additionally at time t0, diaphragm 110 is in a closed state and acts as a barrier between tube section 104 and test chamber 106. When tube section 102, tube section 104, and test chamber 106, are separated by diaphragm 108 and diaphragm 110, the pressure inside of shock tube system 100 is at a constant p0 as shown by function segment 208.
Function segment 210 represents the opening of diaphragm 108 at time t1. At time t1, diaphragm 108 switches from a closed state to an open state, allowing the flow of fluid from tube section 102 into tube section 104. The volume, temperature, and pressure differentials between tube section 102 and tube section 104 creates a primary shock with pressure p1.
The primary shock propagates from tube section 102 and tube section 104 towards test chamber 106 at a constant pressure p1 from time t1 to time t2.
At time t2, diaphragm 110 switches from a closed state to an open state allowing the primary shock to propagate into test chamber 106. When the primary shock enters test chamber 106, it begins to expand as the fluids begin to reach equilibrium in shock tube system 100.
Function segment 212 represents the expansion of the primary shock inside of test chamber 106. At time t2 the primary shock enters test chamber 106 and begins to equalize. This equalization continues until the fluid in test chamber 106 equalizes to a pressure higher than p0 at time t3.
Enhanced blast weaponry such as thermobaric bombs and nuclear devices create shockwaves with multiple shock wavefronts as well as multiple expansion wavefronts. Since conventional shock tubes are only able to create single wavefronts they are not suitable for biomedical research on enhanced blast weaponry injuries and damage mitigation, for example.
What is therefore needed is a system and method that generates a primary and secondary shockwave. Moreover, a system that creates multiple shockwaves will provide researchers with additional fundamental understanding of how multiple shock wavefronts work. With better knowledge of how multiple shock wavefronts work, researchers will, for example, be able to develop methods for injury prediction, injury treatment, and damage mitigation.

System and method for simulating primary and secondary blast


A method for cleaning containers, in particular bottles of glass or plastics, and a cleaning machine with at least one cleaning medium, with the containers cleaned at least in one station preferential for the cleaning result and/or in a procedure step with at least essentially chemical-free cleaning media. The cleaning medium is advantageously a granular material, in particular granular ice, carried under pressure with compressed air or compressed water. The cleaning machine suited for carrying out the method includes downstream of an unpacking and presoaking station, a pre-cleaning station with a high pressure water blasting pre-cleaning section, and subsequently an intensive cleaning station with at least one intensive cleaning section to which a pressure blasting system for chemical-free, granular material and a carrier medium are associated, and a disinfection station following the intensive cleaning station.

It is known, for example in the beverage industry to employ a considerable amount of chemicals, such as caustic solutions or acids, directly at or in the containers and possibly also work with heat for cleaning containers, in particular bottles of plastics or glass, in connection with water. These well-known methods require a considerable amount of water and chemicals per container to be cleaned as well as a considerable amount of energy for generating heat. The high amount of water required is, among others, due to the chemicals not only having to be employed in a certain dilution for cleaning, but also having to be removed without leaving any residue. This results in an enormous amount of costs for cleaning the containers and can also lead to indirect additional costs if, due to the chemicals not having been completely removed without leaving any residue, product recalls for beverages filled into the containers and contaminated by chemical residues become necessary. In filling and packaging engineering, for example for returnable bottles of glass or plastics, the employed cleaning machine is the highest consumer of thermal energy and chemicals, for example in the form of caustic solutions. For example, approximately 30 kJ of thermal energy and approximately 20 ml of a 2.5% caustic solution are required per bottle to be cleaned.
From EP 1 787 662 A, a modular washing and sterilizing machine is known in which dirty objects, in particular used medical instruments, are cleaned and subsequently disinfected in several stations. In a pretreatment station, the dirty objects are prewashed with cold water and/or treated in an ultrasonic bath in one or several cleaning steps. In at least one subsequent washing station, washing is performed with hot water, optionally with added detergents, and here, hot disinfection with subsequent rinsing and drying in a drying chamber is accomplished. The washing operations are performed in washing chambers into which the dirty objects are transported with carts. Hot disinfection is performed with hot water at a temperature of, for example, 90° C. to 93° C. As pretreatment requires less time than the main washing operation with hot disinfection and drying, several parallel main washing stations are employed.
In WO 2007/051473 A, it is suggested to intensively clean returnable glass bottles with a glass powder blasted through a high-pressure medium. For plastic bottles, glass powder is extremely abrasive.
From DE 196 28 842 A, a method for cleaning metallic bottles, such as diving bottles or compressed air bottles, is known, wherein, for internal cleaning, a cleaning substance with granular, abrasive particles of glass scrap of e.g. hardened glass is filled into the bottle either in a dry state or in a liquid, and the bottle is then set in relative motion relative to the cleaning substance. The relative motion comprises a rotation of the bottle about its longitudinal axis and additionally cyclic tilting motions transversely thereto.

Method for cleaning containers and cleaning machine


An apparatus and method for casting a hand bow in a horizontal orientation, to provide reduced forearm slap, increased accuracy, and reduced grip arm fatigue. The horizontal orientation also enables the bow assembly to be used in seated and prone positions, as well as when standing. A grip member having a rearwardly facing alignment channel is mounted or formed on the riser of the bow. The channel is configured to receive and engage the metacarpal head area or another portion of the grip hand so as to form a horizontal pivot axis. The pivot axis is positioned in substantially the same plane as the primary plane of the bow assembly, thereby minimizing development of torque when the bowstring is drawn. A bracket assembly is provided for mounting an arrow rest and sights for use in the horizontal orientation.

a. Field of the Invention
The present invention relates generally to archery bows, and more particularly, to a method and apparatus for casting an archery hand bow in a horizontal orientation, as opposed to the conventional vertical orientation.
b. Related Art
The historical relationship between the stringed stick and mankind is well documented. The discovery of the "Ice Man", frozen in time in the Italian-Austrian Alps with his cedar shafts and yew wood hand bow, accentuates the role that the bow and arrow has played in the colonization of our planet earth. Time has honored the hand bow with relatively few changes in the design and in the techniques that are used to practice the art.
The basic hand bow was formed of an elongated section of wood fashioned with a central handgrip, was tensioned end-to-end by a length of sinew or other string-like material. Modifications in the curvature and length of the riser and limbs have occurred over time and have given rise to more highly developed forms. These bows are generally referred to as "long bows" and "recurve bows".
More recent developments have employed cables, pulleys and eccentric wheels, in combination with composite materials, to enhance the power, speed, draw-weight, holding and shooting properties of bows, while reducing the overall dimensions of the assemblies. This has led to the creation of a new style of archery bow, termed, the "compound bow."
Yet another type of bow that has been developed is the "crossbow," which typically employs a compound type bow mounted to a firearm style butt/stock section. The butt/stock section includes a locking trigger mechanism for the purpose of mechanically holding the draw-weight of the bowstring at full draw, independent of the archer, until the triggering mechanism is operated. Crossbows are therefore "cock-and-shoot" devices that differ greatly from hand bows in which the drawn string is held by the archer's hand. While the present invention may be useful with respect to crossbows in some embodiments, it is directed primarily to use with hand bows and so the following description will focus primarily on the latter.
When using a hand bow, conventional methods call for casting the bow in a vertical or near vertical orientation. This follows time-honored practice, but is the source of several problems. For example, when vertically casting a hand bow, considerable forearm slap is exerted by the bowstring against the archer's grip arm. Not only is forearm slap painful to the archer, but it exerts detrimental torque and transfers destabilizing forces to the arrow, thus adversely effecting the accuracy and the speed of the arrow. Attempts to reduce forearm slap by moving the handgrip off centerline from the plane of the bow riser and limbs (e.g., by modifying the riser so that the grip is off-set to one side of the plane) result in the development of detrimental side torque forces during operation. Thus, in the absence of a satisfactory solution, archers are commonly forced to wear forearm protectors in order to reduce the effects of forearm slap and interference.
Additional disadvantages shared by conventional, vertically-cast hand bows include the following:
(a) There is considerable difficulty operating a hand bow while seated or lying down, and in high and low trajectories, due to bow length and limb interference with surrounding obstacles, such as the archer's body, the ground, a tree stand, tree branches, and so on. PA1 (b) The target must be acquired off-hand, due to the fact that the protruding limbs of a vertically held bow prohibit the use of a stabilizing rest to assist in steadying the bow for target acquisition and accuracy. PA1 (c) The vertical alignment of the wrist causes the forearm to rotate 90 degrees relative to the shoulder, increasing the tendency of the arm to bend at the elbow when the bow is drawn, and also increasing upper arm fatigue in use. This has the effect of reducing the maximum draw weight of a bow that can be used by an individual archer and/or the duration for which it can be used by the archer without having to rest. Furthermore, accuracy tends to deteriorate rapidly with increased fatigue of the grip arm, since the entire grip arm must be raised and lowered in fine increments in order to adjust the aim. PA1 (d) Accuracy further suffers because the vertically held handgrip rests against the soft, fleshly crotch of the hand, between the thumb and forefinger. The natural flexibility and "give" of the muscles and tendons in this area allow the bow to move or wobble slightly when drawn. Also, accuracy again tends to decrease with fatigue, as the muscles of the hand become tired and relax, tending to further soften the tissues against which the bow rests. PA1 (e) The archer's field of view is greatly reduced by the obstructions caused by the vertical bow riser and the accessories that are attached to the riser, such as the arrow rest, sight mount, and arrow quiver, all of which are generally mounted along the plane of the riser.
A number of prior attempts have been made at addressing one or more of the above problems, however, none has been successful in achieving more than a partial solution. For example, several types of "pistol grip" or "wrist rocket" type bows have been proposed, such as those disclosed in U.S. Pat. No. 4,957,093 (Hamlett) and U.S. Pat. No. 3,566,853 (Larm). Both of these references show bows that employ a pistol grip mounted perpendicular to and below the plane of the bow riser and limbs. Although such grip positioning reduces the problem of a forearm slap and presents the bow in a generally horizontal orientation, the offset position of the grip causes this to transmit excessive side torque to the riser and limbs of the bow, to the extent that forearm protectors and pivoting grip interfaces are resorted to in an attempt to minimize and counteract this effect.
U.S. Pat. No. 4,996,968 (Hollingsworth) and U.S. Pat. No. 5,092,308 (Sheffield), in turn, describe bows having horizontal bow grips, positioned parallel to and below the plane of the riser and limbs. Like the pistol grip devices described above, this arrangement suffers from the development of extreme side torque loads, again causing de-stabilizing forces and forcing the use of forearm protectors and compensation structures. For example, the Sheffield bow employs a bowstring alignment shaft to assist in compensating for side torque during drawing of the bowstring; as soon as this string is released, however, the torque becomes unbalanced and adversely influences the launch of the arrow.
A great many other variations on bows, grips and handles are known in the art, including those shown in the following references: U.S. Pat. No. 4,766,874 (Mishioka), U.S. Pat. No. 5,333,595 (Hefforn), U.S. Pat. No. 5,853,000 (Torgerson), U.S. Pat. No. 4,124,014 (Darlington), U.S. Pat. No. 5,853,001 (Vyprachtichy), U.S. Pat. No. 4,787,361 (Vyprachtichy), U.S. Pat. No. 4,343,286 (Thacker), U.S. Pat. No. 5,119,796 (Dehlbom), U.S. Pat. No. 4,889,102 (Martin), U.S. Pat. No. 5,555,875 (Martin), U.S. Pat. No. 4,457,287 (Beddington), U.S. Pat. No. 3,599,621 (Scrobell), U.S. Pat. No. 3,834,368 (Geiger), U.S. Pat. No. 4,258,689 (Barnett), U.S. Pat. No. 4,252,100 (Rickard), U.S. Pat. No. 5,335,645 (Simonds), U.S. Pat. No. 5,260,284 (Pujos, et al) and U.S. Pat. No. 5,243,959 (Savage). All of these, however, suffer from the disadvantages of vertical bows and bows with offset/off center-line grips, as been described above.
Accordingly, there exists a need for an apparatus and method for gripping an archery hand bow that eliminates the forearm slap which is caused by the bowstring. Furthermore, there exists a need for such an apparatus and method in which the wrist is aligned in a horizontal orientation so as to obtain maximum benefit of the musculo-skeletal structure of the grip arm. Still further, there exists a need for such an apparatus and method that will place the bow in engagement with a firm, stable portion of the grip arm/hand so as to achieve maximum stabilization of the bow when drawn. Still further, there exists a need for such an apparatus and method which enables a hand bow to be operated from standing, seated and prone positions. Still further, there exists a need for such an apparatus and method which allows a stabilizing rest to be used to assist the archer in target acquisition and shot accuracy. Still further, there exists a need for such an apparatus and method which will minimize visual obstructions and will present the archer with improved field of view. Still further, there exists such a need for such an apparatus and method which will provide the archer with protection from being injured by a hunting broad-head as this is released and shot from the bow.

Method and apparatus for horizontal casting of an archery bow


An induction logging tool having transmitter and receiver antennas is used to make measurements of earth formations. The antennas may be mounted on the mandrel of a bottomhole assembly for MWD applications, or may be pad mounted for wireline applications. The induction measurements are inverted using a linearized model. The model parameters are determined in part from caliper measurements.

1. Field of the Invention
The present invention relates to well logging. In particular, the present invention is an apparatus and method for imaging of subsurface formations using electrical methods.
2. Background of the Art
Birdwell (U.S. Pat. No. 3,365,658) teaches the use of a focused electrode for determination of the resistivity of subsurface formations. A survey current is emitted from a central survey electrode into adjacent earth formations. This survey current is focused into a relatively narrow beam of current outwardly from the borehole by use of a focusing current emitted from nearby focusing electrodes located adjacent the survey electrode and on either side thereof. Ajam et al (U.S. Pat. No. 4,122,387) discloses an apparatus wherein simultaneous logs may be made at different lateral distances through a formation from a borehole by guard electrode systems located on a sonde which is lowered into the borehole by a logging cable. A single oscillator controls the frequency of two formation currents flowing through the formation at the desired different lateral depths from the borehole. The armor of the logging cable acts as the current return for one of the guard electrode systems, and a cable electrode in a cable electrode assembly immediately above the logging sonde acts as the current return for the second guard electrode system. Two embodiments are also disclosed for measuring reference voltages between electrodes in the cable electrode assembly and the guard electrode systems.
Techniques for investigating the earth formation with arrays of measuring electrodes have been proposed. See, for example, the U.S. Pat. No. 2,930,969 to Baker, Canadian Pat. No. 685,727 to Mann et al., U.S. Pat. No. 4,468,623 to Gianzero, and U.S. Pat. No. 5,502,686 to Dory et al. The Baker patent proposed a plurality of electrodes, each of which was formed of buttons which are electrically joined by flexible wires with buttons and wires embedded in the surface of a collapsible tube. The Mann patent proposes an array of small electrode buttons either mounted on a tool or a pad and each of which introduces in sequence a separately measurable survey current for an electrical investigation of the earth formation. The electrode buttons are placed in a horizontal plane with circumferential spacings between electrodes and a device for sequentially exciting and measuring a survey current from the electrodes is described.
The Gianzero patent discloses tool mounted pads, each with a plurality of small measure electrodes from which individually measurable survey currents are injected toward the wall of the borehole. The measure electrodes are arranged in an array in which the measure electrodes are so placed at intervals along at least a circumferential direction (about the borehole axis) as to inject survey currents into the borehole wall segments which overlap with each other to a predetermined extent as the tool is moved along the borehole. The measure electrodes are made small to enable a detailed electrical investigation over a circumferentially contiguous segment of the borehole so as to obtain indications of the stratigraphy of the formation near the borehole wall as well as fractures and their orientations. In one technique, a spatially closed loop array of measure electrodes is provided around a central electrode with the array used to detect the spatial pattern of electrical energy injected by the central electrode. In another embodiment, a linear array of measure electrodes is provided to inject a flow of current into the formation over a circumferentially effectively contiguous segment of the borehole. Discrete portions of the flow of current are separably measurable so as to obtain a plurality of survey signals representative of the current density from the array and from which a detailed electrical picture of a circumferentially continuous segment of the borehole wall can be derived as the tool is moved along the borehole. In another form of an array of measure electrodes, they are arranged in a closed loop, such as a circle, to enable direct measurements of orientations of resistivity of anomalies
The Dory patent discloses the use of an acoustic sensor in combination with pad mounted electrodes, the use of the acoustic sensors making it possible to fill in the gaps in the image obtained by using pad mounted electrodes due to the fact that in large diameter boreholes, the pads will necessarily not provide a complete coverage of the borehole.
U.S. Pat. No. 6,714,014 to Evans et al., the contents of which are fully incorporated herein by reference, discloses a device suitable for resistivity imaging with water based mud (WBM) and oil based mud (OBM). The device disclosed in the Evans '014 patent is basically a wireline logging device. U.S. Pat. No. 6,600,321 to Evans discloses a modification of the Evans '374 application that is adapted for use in measurement while drilling (MWD) applications. Both of the Evans' patents have pad mounted electrodes that are in contact with the earth formation.
The devices described above are galvanic devices in which current is injected into the formation. With the exception of the Evans patents, they only work when the borehole is filled with a conducting fluid. U.S. patent application Ser. No. 10/657,870 of Ritter et al., filed on Sep. 9, 2003 and the contents of which are fully incorporated herein by reference, teaches the use of galvanic, induction and propagation resistivity devices for borehole imaging in MWD applications. The resistivity sensor may be mounted on a pad, rib, or a stabilizer. Specifically disclosed therein are a shielded dipole antenna and a quadrupole antenna. In addition, the use of ground penetrating radar with an operating frequency of 500 MHz to 1 GHz is disclosed. One embodiment of the Ritter device involves an arrangement for maintaining the antenna at a specified offset from the borehole wall using, for example, hard facing.
The prior art identified above does not address the issue of borehole rugosity and its effect on induction measurements. Being primarily high resolution imaging applications, the problem of "seeing" into the earth formation is generally not addressed. In addition, usually the effect of mud resistivity on the measurements is not addressed. It would be desirable to have a method and apparatus that estimates resistivities of earth formations away from the borehole. Such a method should take into account irregularities in the borehole wall, as well as the effect of mud resistivity. The present invention satisfies this need.

Induction resistivity imaging principles and devices in oil based mud