The power semiconductor module (1) comprises a housing (5), a covering panel (11) and at least two submodules (21, 22). The submodules (21, 22) each comprise at least one semiconductor chip, which has two main electrodes which are electrically conductively connected to main connections (3, 4) of the submodules. The submodules (21, 22) are arranged alongside one another, and one of their two main surfaces is pressed against the covering panel (11) of the module. The submodules are electrically connected in series. The maximun blocking voltage of the module is doubled by connecting the submodules, which are arranged alongside one another, in series. This reduces the length and the costs of the stack for hihg-voltage switch since fewer components are required for the same blocking voltages, in particular fewer modules and cooling elements.

The invention relates to the field of power electronics. It relates in particular to a power semiconductor module as claimed in the precharacterizing clause of patent claim 1.
For high-power applications, power semiconductor modules are manufactured using press pack module technology. These press pack modules are used as high-power switches for currents of up to several thousand amperes in the high-voltage range up to 1000 kV. Since insulated gate bipolar transistors (IGBT), as are used nowadays in a press pack module, can withstand a voltage of only around a few thousand volts, a number of press pack modules are connected in series in at least one stack for a high-voltage switch. The stack, with up to several dozen press pack modules, is compressed with a force of around 100 kN.
A conventional press pack module, such as that described in EP 762,496, generally has a number of semiconductor chips which are arranged alongside one another and are mounted with a first main electrode on a base plate. Second main electrodes of the semiconductor chips are made contact with by a number of contact dies. The base plate is connected to a first main connection, and the contact dies are connected to a second main connection. The main connections may be in the form of disks, and may be interconnected by means of flanges. The contact die has spring elements, by way of example, which press against the individual chips.
The individual semiconductor chips in the press pack module are formed into several groups and are combined in units, so-called submodules, which can be prefabricated. In this case, the semiconductor chips are connected in parallel with one another, for example with one IGBT and one diode chip together in one submodule.
A press pack module such as this is described in the attached European Patent Application with the Application Number 01810539.5, and is illustrated schematically in FIG. 1. The figure is split into two halves, with the left-hand half showing one half of the module in the preinstalled state, and the right-hand half showing the other half of the module, in the installed state in a stack of three modules.
The module with the three illustrated submodules 2 is in this case pressed against an electrically and thermally highly conductive base plate 12, which, by way of example, may be a cold plate through which a cooling liquid flows.
Even in the preinstalled state, the submodules 2, which are introduced into the insulating housing 5 from above, have a spring stress applied to them and are pressed against the covering panel 11, which is firmly connected to the insulating housing. The spring stress is produced by spring elements in the individual submodules, and is transmitted to the first main connections 3. The second main connections 4 project downward out of the insulating housing 5, in order to ensure reliable contact with the base plate 12.
In the installed state, the second main connections 4 of the submodules are pressed into the interior of the module housing by means of a contact force that is exerted on the base plate and the covering panel. In the process, the spring elements are compressed, so that the contact force acting on the electrodes of the semiconductor chips in the interior of the submodules is increased. The insulating housing in this case ensures that the spring elements are not compressed excessively, so that the contact force does not become too great.
A stack with press pack modules extends over a length of several meters. Complex precautions are necessary in order to allow the pressure mentioned above to be exerted over such a length. It is thus desirable to increase the maximum blocking voltage per unit length in a stack, in order to manage with fewer press pack modules for a given voltage.
The height of the stack, and hence the costs associated with it, could be reduced by increasing the blocking voltage of individual press pack modules. Unfortunately there is scarcely any prospect of raising the maximum blocking voltage, as mentioned above, of power semiconductor chips with present-day technology.
The object of the present invention is thus to provide a power semiconductor module of the type mentioned initially, which has a greater blocking voltage per physical height unit.
This object is achieved according to the invention by a power semiconductor module having the features of patent claim 1.
The power semiconductor module according to the invention has at least two submodules between two main electrical connections which are arranged on mutually opposite, essentially parallel, main surfaces of the module. The submodules have two main electrical connections which are arranged on in each case one of two mutually opposite, essentially parallel, main surfaces of the submodules. The submodules comprise in each case at least one semiconductor chip, which has two main electrodes, which are electrically conductively connected to the main connections of the submodule. The submodules are arranged alongside one another, and one of their two main surfaces is pressed against the covering panel. At least two submodules are electrically connected in series.
In comparison to conventional press pack modules, the blocking voltage can be doubled or increased by several times by connecting two or more submodules, which are arranged alongside one another, in series.
This reduces the length and the costs of a stack, since fewer components, in particular fewer cooling elements, are required for the same blocking voltages.
The physical height of the power semiconductor module according to the invention is only slightly greater than that of conventional press pack modules. However, the additional increase in size leads to the module being more mechanically robust, and this is particularly advantageous in long stacks, in particular.
It is also possible to use better semiconductor chips, with a lower blocking voltage, in comparison to conventional press pack modules, for the same or greater blocking voltages. Since semiconductor chips such as these, with half the blocking voltage, together produce fewer losses than an individual semiconductor chip with the full blocking voltage, it is also possible to reduce the losses in conventional stacks with the same dimensions, by using power semiconductor modules according to the invention.
In a first embodiment of the power semiconductor module, the first main connection of at least one first submodule is electrically conductively connected to the covering panel. A first electrically insulating layer is arranged between the second main connection of the at least one first submodule and that main surface of the module which is opposite the covering panel, and a second electrically insulating layer is arranged between the first main connection of at least one second submodule and the covering panel. The second main connection of the at least one second submodule is electrically conductively connected to the second main connection of the module. The second main connection of the at least one first submodule is electrically conductively connected to the first main connection of the at least one second submodule, via a connection.
The submodules are electrically connected in series, so that the blocking voltage of the power semiconductor module with IGBT semiconductors is doubled.
In a second embodiment of the power semiconductor module, a first electrically insulating layer is arranged between the first main connection of at least one first submodule and that main surface of the module which is opposite the covering panel. The first main connection of the at least one first submodule is electrically conductively connected to the covering panel via a first connection. A second electrically insulating layer is arranged between the second main connection of the at least one first submodule and the covering panel, as well as between the first main connection of at least one second submodule and the covering panel. The second main connection of the at least one second submodule is electrically conductively connected to the second main connection of the module. The second main connection of the at least one first submodule is electrically conductively connected to the first main connection of the at least one second submodule via a second connection.
With the same alignment in the module, the submodules are connected electrically in series, back-to-back. Using IGBT semiconductors, this results in a four-quadrant power semiconductor module which can be switched off and is used, by way of example, as an alternating-current switch in a matrix converter.
Further exemplary embodiments and advantages can be found in the corresponding dependent claims.


A conductive circuit containing a polymer composite, which contains at least one polymer and a modified graphite oxide material, containing thermally exfoliated graphite oxide having a surface area of from about 300 m2/g to 2600 m2/g, and a method of making the same.

1. Field of the Invention
The present invention relates to a high surface area material based on modified graphite oxide.
2. Discussion of the Background
There has been considerable interest in the area of nanoparticle-filled polymer composites (NCs), in particular composites in which the nanoparticle has dimensions comparable to those of the polymer chains, has a high aspect ratio of more than 100 and is uniformly dispersed in the polymer matrix. There are several filler materials that have been extensively studied for improvement of mechanical properties, electrical and thermal conductivity of polymer composites, for example, fractal agglomerated nanoparticles (silica and carbon black), carbon nanotubes (CNTs), inorganic clays and alumina silicate nanoplates.
Initial attempts at producing nanoparticle-filled polymer composites often resulted in materials with inadequate nanoparticle dispersion and degraded mechanical properties. Although often impractical for industrial applications, small-scale dispersion methods involving solvent- or monomer based processing have occasionally yielded NCs with multifunctional capabilities and improved mechanical properties. Several problems remain that affect the development of NCs with consistent properties that are viable for use in real world applications: (1) many of the nanoparticles used are expensive (e.g., CNTs); (2) often chemical or mechanical manipulations must be performed to achieve good dispersion that are impractical for large-scale commercial production; and (3) problems of the interfacial energy mismatch of inorganic nanofillers with hydrocarbon polymer matrix phases result in processing and mechanical property difficulties.
A significant amount of work has been done with nanoclays. Nanoclay-reinforced composites have shown enhancements in stiffness, glass transition temperature, barrier resistance, and resistance to flammability in a variety of polymer systems. Nanoclays are also high aspect ratio nanoplates that are, like graphene, derived from inexpensive commodity materials (clays) and thus appropriate for comparison with the projected graphene polymer composites of the present invention. The in-plane modulus of clays should be similar to that of mica, which is ˜178 GPa, significantly lower than the 1060 GPa value of graphene (value from graphite in-plane). Recent studies point out that the hydrophilicity of clays makes them incompatible with most polymers, which are hydrophobic. One approach is to render the clays organophilic through a variety of approaches (amino acids, organic ammonium salts, tetra organic phosphonium). Such clays are called "organoclays." These materials have suffered from the cost of the added interfacial modifiers and the instability of these modifiers under processing conditions. In addition, it has been difficult to homogeneously disperse these organoclays in polymer matrices.
Carbon nanotubes have also generated significant interest as nanofillers. They have good mechanical properties and large aspect ratios, and their surfaces should be more compatible with hydrocarbon polymers than clay-based nanofillers. As a nanofiller, CNTs have several limitations, one of which is their cost of production. Since they are made in a gas-phase process, the production costs are more expensive than solution-based processes operating at high density. The production of single wall carbon nanotubes (SWCNTs) requires the addition of metal catalysts that must be removed to produce pure SWCNT materials, or results in the presence of heavy metal contaminants in the final materials if not removed.
Graphite is a "semi-metal," and recent efforts have demonstrated that extremely thin (few layers thick) nanoplates obtained from highly oriented pyrolytic graphite (HOPG) are stable, semimetallic, and have exceptional properties for metallic transistor applications.
Even though graphene sheets have the same sp2 carbon honey comb structure as carbon nanotubes (CNTs), until now, it has not been possible to effectively produce the highly dispersed, thin sheets needed to make graphene applications possible.

This patent is subject to a terminal disclaimer.

Conductive circuit containing a polymer composition containing thermally exfoliated graphite oxide and method of making the same


A choke valve control system includes a choke-operating lever for opening and closing a choke valve of a carburetor, a choke spring for biasing the valve in an opening direction, and a damper for controlling the opening motion of the valve to a lower speed, when the choke valve is opened from its fully closed position by a biasing force of the choke spring. The choke-operating lever, the choke spring and the damper are connected to the choke valve of the carburetor. In this choke valve control system, the damper includes a damper housing, a rotor, and a damper oil which is accommodated in a sealed manner in the damper housing and applies a viscosity resistance to the rotation of the rotor, which resistance increases as the viscosity increases with decreasing temperature. Thus, the time required for opening the choke valve can be controlled in accordance with the level of the environmental temperature of an engine, thereby providing the stabilization of the warming operation of the engine and a reduction in fuel consumption.

1. Field of the Invention
The present invention relates to an improvement in a control system for a choke valve of a carburetor, including a choke-operating lever for opening and closing the choke valve of the carburetor, a choke spring for biasing the valve in an opening direction, and a damper for controlling the opening motion to a lower speed, when the choke valve is opened from its fully closed position by a biasing force of the choke spring. The choke-operating lever, the choke spring and the damper are connected to the choke valve of the carburetor, so that after starting of an engine with the choke valve closed, the choke valve is opened automatically in response to the progress of the warming operation of the engine, thereby providing the stabilization of the warming operation and a reduction in fuel consumption.
2. Description of the Related Art
In a conventional control system for the choke valve of the carburetor, the damper an air type in which the opening motion of the choke valve is slowed down by a damping force generated upon passing of air through an orifice (see Japanese Utility Model Application Laid-open No. 63-24354.
For providing the stabilization of the warming operation and a reduction in fuel consumption, it is important that the time required from the full closing to the full opening of the choke valve after starting of the engine is controlled in accordance with the level of the environmental temperature of the engine. Namely, it is necessary to provide the choke valve control system with the characteristic that the lower the environmental temperature, the longer the required time for the valve to go from fully closed to fully open.
In the control system for the choke valve of the carburetor using the air damper, as described above, however, the damping force generated in the air damper is constant irrespective of the level of the environmental temperature of the engine and hence, the time required for fully opening the choke valve controlled by the control system is also constant. Thus, it is impossible to satisfy the above-described required characteristic.
Accordingly, it is an object of the present invention to provide a control system for a choke valve of a carburetor, which is designed so that the above-described required characteristic can be satisfied.
To achieve the above object, according to the present invention, there is provided a control system for a choke valve of a carburetor, comprising a choke-operating lever for opening and closing the choke valve of the carburetor, a choke spring for biasing the valve in an opening direction, and a damper for controlling opening motion of the choke valve to a lower speed, when the choke valve is opened from its fully closed position by a biasing force of the choke spring, the choke-operating lever, the choke spring and the damper being connected to the choke valve of the carburetor, wherein the damper is an oil type using a damper oil whose viscosity is increased in accordance with a temperature drop or decrease.
With the first feature, a damping force generated by the oil damper is increased in accordance with the decrease of the environmental temperature of the engine. Therefore, the time required from the full closing to the full opening of the choke valve can be controlled, so that the time is longer when the environmental temperature is lower, and the time is shorter when the environmental temperature is higher. Thus, it is possible to satisfy the easy/ready startability of the engine, the stabilization of the warming operation of the engine and a low fuel consumption.
According to a second feature of the present invention, in addition to the first feature, the damper comprises a damper housing, a rotor rotatably housed in the damper housing, and the damper oil accommodated in a sealed manner in the damper housing and applying a viscosity resistance to the rotation of the rotor, the damper housing being supported on a stationary structure, and the rotor being connected to the choke valve so that the rotor is rotated in operable association with the opening and closing of the choke valve.
With the second feature, the damper can be constructed compactly by a small number of parts, which can contribute to a reduction in cost of and the compactness of the choke control system.
The stationary structure corresponds to a bracket 14 in each of embodiments of the present invention which will be described hereinafter.
According to a third feature of the present invention, in addition to the first or second feature, a driven member is connected to a valve stem of the choke valve, and a resilient driving member is connected to the choke-operating lever and adapted to be flexed to urge one side of the driven member in operable association with the operation of the choke-operating lever in a direction of closing of the choke valve, thereby closing the choke valve.
With the third feature, fabrication errors of various portions of the choke valve control system are absorbed by the flexing of the resilient driving member, and the choke valve can be brought reliably and at any time into the fully closed state.
The driven member and the resilient driving member correspond to a driven pin and a resilient driving plate 47 in each of the embodiments of the present invention which will be described hereinafter.
According to a fourth feature of the present invention, in addition to the second feature, a cam adapted to be rotated in operable association with the opening and closing operation of the choke-operating lever, and a cam follower adapted to be moved following a cam surface of the cam to open and close the choke valve are interposed between the choke-operating lever and the choke valve.
With the fourth feature, after starting of the engine with the choke valve fully closed, the time required for fully opening the choke valve is controlled by the damper, E and the opening degree of the choke valve during such controlling is controlled by the cam surface. Therefore, a desired opening degree characteristic assuring that the fully closed state is maintained, can be provided to the choke valve during the passage of time by the selection of the shape of the cam surface, thereby providing the stabilization of the warming operation and an enhancement in low fuel consumption.
According to a fifth feature of the present invention, in addition to the first feature, the damper comprises a damper housing and the damper oil accommodated in a sealed manner in the damper housing and applying a viscosity resistance to the rotation of a rotor, the damper housing being supported on a stationary structure, and wherein the rotor and the cam are connected to each other through an accelerating mechanism for accelerating the rotation of the cam to transmit it to the rotor.
With the fifth feature, a damping force generated by the damper is increased in accordance with a drop or decrease of the environmental temperature of the engine. Therefore, the time required for fully opening the choke valve can be controlled automatically, so that the time is longer when the environmental temperature is lower, and the time is shorter when the environmental temperature is higher. Thus, it is possible to satisfy the easy/ready startability of the engine, the stability of the warming operation of the engine and a low fuel consumption.
Moreover, the damper can generate sufficient damping force, although the damper is compact, by transmitting the rotation of the cam to the rotor of the damper through the accelerating mechanism and thus, it is possible to provide a satisfactory time required for fully opening the choke valve.
According to a sixth feature of the present invention, in addition to the first feature, the damper comprises a damper housing, a rotor rotatably housed in the damper housing and the damper oil which is accommodated in a sealed manner in the damper housing and whose viscosity is increased in accordance with a temperature drop to apply a viscosity resistance to the relative rotation of the rotor and the damper housing, one of the damper housing and the rotor being secured to a stationary structure, the choke-operating lever being integrally connected to the other of the damper housing and the rotor, and wherein a return spring for biasing the choke-operating lever in a direction to open the choke valve is connected to the choke-operating lever.
With the sixth feature, a damping force generated by the oil-type damper is increased in accordance with a decrease of the environmental temperature of the engine. Therefore, the time required from the full closing to the full opening of the choke valve can be controlled automatically, so that the time is longer when the environmental temperature is lower, and the time is shorter when the environmental temperature is higher. Thus, it is possible to satisfy the easy/ready startability of the engine, the stability of the warming operation of the engine and a low fuel consumption.
In addition, the oil-type damper comprising the damper housing, the rotor and the damper oil is constructed by a small number of parts to be compact. Moreover, it is possible to reduce the number of parts of the choke valve control system by the integral connection of any one of the damper housing and the rotor with the choke-operating lever, to thereby simplify the structure to provide the compactness and reduce the cost of the choke valve control system.
According to a seventh feature of the present invention, in addition to the sixth feature, the choke-operating lever is provided with a cam which is engaged with a cam follower supported on the stationary structure and operably connected to the choke valve, the cam being formed so that the motion of the choke-operating lever for opening the choke valve is transmitted through the cam follower to the choke valve in a retarded manner.
With the seventh feature, even if the turning speed of the choke-operating lever in the direction to open the choke valve, which is determined by the damping force of the oil damper and the return spring, is constant, the opening of the choke valve can be retarded as desired by the shape of the cam to provide the easy/ready startability of the engine and the stabilization of the warming operation of the engine.
According to an eighth feature of the present invention, in addition to the first feature, a cam adapted to be rotated in operable association with the opening and closing operation of the choke-operating lever and a cam follower adapted to be moved following a cam surface of the cam to open and close the choke valve are interposed between the choke-operating lever and the choke valve.
According to a ninth feature of the present invention, in addition to the eighth feature, the damper comprises a damper housing, and the damper oil which is accommodated in a sealed manner in the damper housing and applies a viscosity resistance to the rotation of a rotor, the damper housing being supported on a stationary structure, and wherein the rotor and the cam are connected to each other through an accelerating mechanism for accelerating the rotation of the cam to transmit it to the rotor.
According to a tenth feature of the present invention, there is provided a control system for a choke valve of a carburetor in a power working machine including an engine which has a cooling fan mounted at an upper end of a crankshaft disposed vertically, a working device connected to a lower end of the crankshaft, and an engine cover which has a cooling-air intake port opposed to the cooling fan and covers an upper surface of the engine so that cooling air drawn through the cooling-air intake port by the cooling fan is guided to the engine, the control system comprising: a choke-operating lever for opening and closing a choke valve of a carburetor mounted on one side of the engine; a choke spring for biasing the choke valve in an opening direction; and a damper for controlling the motion of opening of the choke valve to a lower speed, when the choke valve is opened from its fully closed position by a biasing force of the choke spring, wherein the damper an oil type using an damper oil whose viscosity is increased in accordance with a temperature decrease.
According to an eleventh feature of the present invention, in addition to the tenth feature, the damper is disposed in a path for the cooling air extending from the cooling-air intake port to the engine.
With the eleventh feature, the cooling air drawn through the cooling-air intake port in the engine cover by the cooling fan during operation of the engine is passed through the damper and around the damper in a course of being fed under pressure to the engine, whereby it blows away dusts deposited on the damper and parts of the choke valve control system connected to the damper to clean them. Therefore, it is possible to prevent the dusts blown up by the working device from being accumulated on the damper and the like, thereby also preventing any associated malfunction of the damper and the like, and cooling the damper to enhance the durability thereof.
According to a twelfth feature of the present invention, in addition to the tenth feature, a tip end of the choke-operating lever is disposed to protrude outside of the engine cover.
With the twelfth feature, the choke-operating lever can be opened and closed easily without being obstructed by the engine cover. Moreover, the choke-operating lever can be visually seen and hence, it is easy to confirm the position of the choke-operating lever and it is possible to easily carry out the appropriate control of the choke valve.
According to a thirteenth feature of the present invention, in addition to the tenth feature, the power working machine further includes a braking mechanism capable of braking the rotation of an output shaft of the engine, and a brake release mounted on a steering handle bar for releasing the operational state of the braking mechanism; the choke-operating lever, the choke spring and the damper are connected to the choke valve; the choke-operating lever is adapted to be turned between an opening position and a closing position to open and close the choke valve; and a locking mechanism is interposed between the choke-operating lever and the braking mechanism and adapted to lock the choke-operating lever at the closing position when the braking mechanism is in operation, and to release the locked state of the choke-operating lever when the operation of the braking mechanism is released.
With the thirteenth feature, when the operation of the braking mechanism is released, the locked state of the choke-operating lever is released automatically in operable association with the releasing of the operation of the braking mechanism, and the closing of the choke valve is controlled automatically to a lower speed. Therefore, a special operation for returning the choke-operating lever is not required and thus, it is possible to alleviate a burden on an operator, and also to prevent the malfunction of the engine and the degradation of the fuel consumption due to the operator forgetting to open the choke valve.
According to a fourteenth feature of the present invention, in addition to the thirteenth feature, the damper is comprised of a damper housing, a rotor rotatably housed in the damper housing and the damper oil accommodated in a sealed manner in the damper housing and applying a viscosity resistance to the rotation of a rotor, the damper housing being supported on a stationary structure, and wherein the rotor and a cam operatively associated with the choke-operating lever and the choke valve are connected to each other through an accelerating mechanism for accelerating the rotation of the cam to transmit it to the rotor.
With the fourteenth feature, a damping force generated by the damper is increased in accordance with the decrease of the environmental temperature of the engine. Therefore, the time required for the full opening of the choke valve can be controlled, so that the time is longer when the environmental temperature is lower, and the time is shorter when the environmental temperature is higher. Thus, it is possible to satisfy the easy/ready startability of the engine, the stabilization of the warming operation of the engine and a low fuel consumption.
Moreover, the damper can generate a sufficient damping force although the damper is compact, thereby providing a satisfactory time required for the full opening of the choke valve, by transmitting the rotation of the cam through the accelerating mechanism to the rotor of the damper.
The above and other objects, features and advantages of the invention will become apparent from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings.

Control system for choke valve of carburetor


Methods and apparatus to decode dual-tone signals are disclosed. An example receiver to decode a dual-tone signal includes a tone detector to detect a start of a first tone, a first counter to count first cycles of the first tone, a second counter to count second cycles of a system clock while the first counter is counting and the first count is less than a first threshold, state control logic to start the second counter counting third cycles of the clock when a time period elapses, the third count being substantially equal to the second count, the first counter to count fourth cycles of a second tone while the third cycles are counted, and a decoder to compare the fourth count to a second threshold to identify an event represented by the signal.

Information can be sent over a communication medium such as a wire using tones of different amplitude, phase and/or frequency. For example, information can be transmitted using a dual-tone signal comprising a first tone having a first frequency and a second tone having a second frequency. To accommodate transmitters and receivers that use asynchronous clocks, data is encoded in a dual-tone signal based on the ratio of the two frequencies rather than based on the actual first and second frequencies. To receive data encoded or represented by a dual-tone signal, a receiver may estimate the first and second frequencies, compute a ratio of the estimated frequencies, and decode the ratio to determine the transmitted data.


A wireless infrastructure that communicates with a DHCP server and a wireless client that rotates its MAC address performs a method including: upon receiving, from the wireless client, a first request with a first MAC address, creating a session context including the first MAC address and a stable identifier, and relaying the first request to the DHCP server; relaying, from the DHCP server to the wireless client, a first DHCP reply that includes an Internet Protocol (IP) address bound to the stable identifier; upon receiving, from the wireless client, a second request with the IP address and a second MAC address, merging the second MAC address and the IP address into the session context, and relaying, to the DHCP server, the second request including the stable identifier; and relaying, from the DHCP server to the wireless client, a second DHCP reply including the IP address bound to the stable identifier.

Randomized and changing media access control (MAC) (RCM) address techniques have been used by wireless client devices (also referred to herein simply as "wireless clients") for some time. Wireless clients rotate their MAC addresses for privacy reasons, and to avoid being tracked. When a wireless client rotates its MAC address while engaged in a communication session with a wireless infrastructure, the MAC address rotation may cause an undesired momentary disassociation from the wireless infrastructure. Such disassociation may also disrupt wired connectivity for the communication session between the wireless infrastructure and a wired network. Conventional RCM techniques do not support MAC address rotation within a single communication session, without disassociation from the wireless infrastructure. Moreover, current IEEE 802.11 specifications do not provide for such operation.

DHCP resource optimization for randomized and changing MAC address


The present solenoid stator assembly mounts on a seat forming part of a fuel injector, secured to it by mounting bolts. A rigid metal outer housing has a base shaped to fit upon the mounting seat of the fuel injector and defines an interior chamber. An E-shaped stator core is located centrally within the interior chamber and an insulated plastic inner housing extends between the stator core and the outer housing to fixedly secure the core within the interior chamber. The outer housing reinforces the insulated plastic inner housing against the bulging forces imposed by high fuel pressure and protects it against damage from external blows.

Most engines of trucks commonly used in the trucking industry now utilize fuel injectors to deliver an atomized fuel charge to the engine cylinders. Art electronic timing circuit delivers precisely timed electrical pulses for operation of the fuel injector. Such pulses are used in a solenoid stator assembly to reciprocate a solenoid plunger mounted in the fuel injector which controls the injection of fuel into the associated engine cylinder.
The solenoid stator assembly commonly requires a housing to protect its electrical components and to locate them precisely in relation to the reciprocating solenoid plunger. Commonly, such housings have involved insulative plastic housing components surrounding a stator core. The stator core extends through a stator coil which is pulsed with the electrical current to generate the magnetic forces necessary to reciprocate the plunger. In the design of such stator assemblies, it is necessary to overcome severe difficulties created by the very harsh working environment in which the assembly must function.
The stator assembly must be able to accommodate wide variations in operating temperature, from cold start up at below zero temperatures to under the hood temperatures in hot desert conditions exceeding 200.degree. F., causing significant thermal expansion and contraction of the housing components. Leaking fuel droplets under high pressure from the injector can create high pressure within the interior of the plastic housing leading to cracking of the plastic. Over time and under these conditions of inter vibration and fluctuating temperature, plastic components of a housing can develop cracks and hairline fractures. Moreover, the plastic housing components can eventually become embrittled. Also, plastic components are at risk of impact damage if persons servicing the engine accidentally impact them with wrenches or other tools during the course of working on adjacent structures. Fuel injectors under current conditions of operation operate a fuel injection pressures of the order of 2000 pounds per square inch pressure. Escape of fuel under such high working pressures from leaking mechanical portions of the fuel injector can direct extremely high pressure of fuel against the plastic stator housing. The entry of such fuel into a crack in the plastic tends to expand and increase the crack and can cause eventual failure of the housing.
Various types of solenoid stator assembly have been developed to address these problems. One such stator assembly is shown in U.S. Pat. No. 5,155,461 to Teerman et al. for "Solenoid Stator Assembly for Electronically Actuated Fuel Injectors and Method of Manufacturing Same," owned by Diesel Technology Corporation. The Teerman patent discloses an actuator assembly for use with a fuel injector of the same type that the present invention is intended to function with. It has an E-shaped stator core having outer and central pole pieces received within a plastic housing that is bolted to a mounting base on the fuel injector. To prevent passage of leakage fuel under high pressure between the stator core and the housing, the Teerman device incorporates T-shaped notches in the outer faces of the stator pole pieces, into which the plastic material of the housing is molded, to present a barrier against the passage of fuel. The Teerman device is constructed by a process which involves prestressing the outer pole pieces of the core outwardly before the housing is molded about it. The prestressing provides restorative forces to oppose additional, fuel pressure related, forces that might be applied to the outer pole pieces and inhibit additional displacement.
While the T-shaped slots in the outer pole pieces of the Teerman device may be effective to resist fuel migration, it may require an additional machining step to provide such T-shaped slots thereby contributing to the manufacturing cost of the stator core. Additionally, the need to prestress the outer pole pieces before molding the housing around the stator core requires additional process steps during the manufacturing process. Finally, the use of a plastic housing which is directly vulnerable to accidental impacts from mechanical objects and to direct impingement by high pressure of fuel leaves the housing susceptible to the types of problem generally noted above.

Solenoid stator assembly for electronically actuated fuel injector


An integrated supply platform system may include a blockchain database maintained by a blockchain network having a plurality of nodes. A plurality of tokens may be maintained in the blockchain database. The system may include smart contracts describing a deal between one or more users, and the smart contracts may be configured to transfer at least one token between the users upon completion of the deal. The system may include communication logic which may be executable by a processor of a client device and configured to communicate data of the smart contract between the client device and the blockchain database. A virtual machine logic may be stored in a memory of a node of the blockchain network. The virtual machine logic may be executable by a processor of the node of the blockchain network and configured to incorporate the data of the smart contract into the blockchain database.

Holding companies have been a part of the business and investing landscape for many decades. Some of the most well-known companies in the world, including Alphabet (Google), Berkshire Hathaway, General Electric and Bank of America are operated as holding companies. Benefits of a holding company structure include the minimization of risks through diversification, and allows shared infrastructure to quickly attain economies of scale. However, holding companies currently lack access to a supply platform in which all portfolio companies leverage a common native currency and blockchain technology platform that enables streamlined supply chain management, B2B marketplace transactions supported by trustless smart contracts and advanced data analytics. Therefore, a need exists for novel computer-implemented systems and methods for a supply platform using an integrated blockchain and utility tokens which will allow portfolio companies to benefit from vertical and horizontal integration opportunities with other operating companies.


An apparatus for removing non-volatile residues and impurities from a used solvent includes a self-scrubbing heating distillation subassembly for separating purified solvent for reuse and a controlled waste collector subassembly for overflowing concentrated residues and impurities stripped from the used solvent into an easy-to-service container. The apparatus may be disposed in a parallel in-line relationship with a circulating solvent flow circuit, such as in a dry cleaning operation, to continuously withdraw and purify aliquot portions of the circulating solvent stream, returning good solvent back to the flow circuit and concentrating non-volatile residues and impurities to a removable, environmentally sound serviceable container. The new and improved self-scrubbing heater assembly causes a rapid turbulent reboiling flow of solvent within a confined column and substantially avoids build up of residues on heat exchange surfaces for prolonged heater life and longer uninterrupted service life before service is needed.

The present invention relates to recent improvements in the handling and utilization of potentially harmful substances, such as organic solvents, to improve environmental safety associated with their use. More particularly, it relates to a new and improved apparatus and method for removing residues and impurities from a circulating solvent flow circuit including a self-scrubbing thermosyphon distillation subassembly for separating purified solvent for return to the flow circuit and a controlled waste collector subassembly for overflowing concentrated residues and impurities into an easy-to-service container.
Recently, the number of kinds of organic solvents commercially employed in a variety of end use applications has increased. Hydrocarbons, halohydrocarbons, fluorocarbons and aromatic solvents are now employed in a number of cleaning applications. Dry cleaning operations for clothing, sometimes referred to as chemical cleaning in Europe, may be the most widespread use for organic solvents of this type. Other uses include cleaning operations for electronic equipment, e.g., refluxing of printed circuit boards. Moreover, various metal cleaning and parts washing apparatus employ special solvents. Some metal cleaning operations prepare surfaces to receive paint or other coatings. Alternatively, solvents may be used to soften and remove unwanted paint and coatings from various substrates such as, for example, in spray guns or other automatic painting equipment.
Concurrently, an awareness of the possibility of environmental damage caused by careless handling and disposal of these organic solvent materials has also increased. Concerns over contamination of ground water supplies caused by the leaking and spilling of used or contaminated solvent onto the ground has long been a concern. More recently, it has been suggested that uncontrolled release of some or all of these organic solvent vapors into the atmosphere may be harmful. Release of some materials may cause a health hazard by increasing the ozone content of the lower atmosphere. Other materials are believed to cause an increased degradation of the ozone layer in the upper atmosphere. Various chlorinated fluorocarbons have been seriously implicated in this regard and a reduction and eventual ban of their use has been recommended by international agreements, such as the Montreal Protocol. Additional health concerns have been noted with respect to the possible carcinogenicity of low molecular weight hydrocarbon and halo-hydrocarbon materials.
The environmental, health and safety concerns surrounding a common end use application for controlled organic solvents is well illustrated by the case of a small to moderately-sized commercial dry cleaning operation. In a commercial dry cleaning operation, customers clothes are collected at a storefront location. The clothes are washed in cleaning machines located on the premises or at a separate location. The clothes are tumbled in an amount of a cleaning solvent which is periodically circulated in batches into the cleaning machines from a reservoir. After agitation of the clothes in the presence of the fluid takes place, the cleaning fluid, usually 1,1,1-trichloroethane (prohibited as of 1995), tetrachloroethylene, or 1,1,2-trichloro-1,2,2-trifluoroethane (known as CFC-113 or Freon.RTM.113 (DuPont)) is drained into a collecting basin associated with the clothes washing units. Additional fluid remaining on the clothes is extracted by spin cycling and this additional solvent is added to the collecting basin.
The used, collected cleaning solvent is then returned to the reservoir and is recycled and continuously used from the reservoir until it is time to replenish the solvent supply, in whole or in part. Frequently, during a portion of the dry cleaning solvent circulation cycle, the solvent may be subject to treatment for removal of solids or particulate matter, namely, lint, grit and the like by means of filters and for removal of water or the like by liquid separators.
In the course of repeatedly re-using the dry cleaning solvent, the solvent per se is not degraded or damaged but becomes contaminated with non-volatile residues and impurities of varying kinds. Normally, the kinds of impurities miscible with a cleaning solvents are oily residues from a number of sources, such as body fluids, air pollution and various foods and beverages. As the concentration of these non-volatile residues builds up in the solvent, the solvent becomes increasingly less effective at cleaning. Eventually, the entire batch of solvent must be removed containerized and transported to a recycling or disposal center.
At this point a number of disadvantages and environmental concerns may be identified. It is now well known that every effort should be made to reduce, reuse and recycle potentially harmful materials. Reuse of the solvents is currently practiced, but after a given level of contamination is reached, re-conditioning or replacement of the solvent is required. Recycling of the dry cleaning fluids however also presents special additional risk factors to be considered. During recycling care should be taken to reduce or eliminate the risk of spillage and/or of exposing volatile organic solvents to humans and the atmosphere. Removing the solvent from the dry cleaning circuit and placing it into containers for shipment to a treatment center introduces the added possibility for spillage and exposure to vapors. Furthermore, transporting the containers to a remote solvent reconditioning center increases the risk of spillage and exposure because of the risk of highway or rail accidents. For these reasons providing a controlled, on-site solvent regeneration system is clearly more desirable than shipping new solvent to a location and shipping used solvent away from the same location on a frequent basis.
Prior art equipment for separating re-usable solvent fractions from non-volatile residues and impurities introduced into the solvent during use have generally been based on distillation equipment and has not been altogether satisfactory. Prior art distillation equipment is generally involves heating with high pressure steam by means of a jacket located in a wall of the distillation vessel. Sometimes a tube bundle is used as a heat source. Frequently, a motor-driven agitator designed to scrape the walls is provided. The prior art scraper systems are generally ineffective to prevent deposition of resinous coatings on the heat transfer surfaces. Once deposition occurs, heat transfer is impeded or halted completely. At this point, it becomes necessary to dismantle the distillation equipment to permit the interior of the vessel to be scraped and cleaned exposing workers and the environment to chemical vapors.
Prior art batch stills usually comprise manually operated apparatus requiring undesirably high amounts of solvent handling. In the case of stills used for dry-cleaning solvents, direct heating without agitation is typical. In the hands of an unskilled operator with little or no distillation background, these stills are frequently operated at overheating temperatures. Overheating causes residue decomposition which may also produce and introduce secondary contaminants into the air or solvent which are possibly toxic. Moreover, overheating causes excess carry-over of residues resulting in unsatisfactory separations.
In one prior art still equipped with a wall scraping stirrer/agitator and adapted for solvent flow rates of as high as 500 gallons per hour, the heating surfaces become coated and ineffective after only about one hour.
In view of the failure of the prior art to provide effective devices and methods for providing environmentally-safe cleaning and regeneration/separation of re-usable solvent from non-volatile residues (NVRs) on the premises, it is an object of this invention to provide improved apparatus and methods for accomplishing on the premises cleaning and regeneration/separation of re-usable solvent from non-volatile residues (NVRs).
It is another object of this invention to provide a new and improved still apparatus for concentrating NVRs and other impurities for batch collection and removal in easy-to-service containers.
It is a further object of the present invention to provide a new and improved apparatus for regenerating clean solvent including a self-scrubbing thermosyphoning heat transfer assembly which does not become dirty and retains its heat transfer efficiency, even after prolonged periods of continuous operation and even when exposed to NVR concentrations in excess of 40%.
It is still another object of the present invention to provide a new and improved solvent distillation apparatus adapted to be placed in a parallel in-line relationship with a circulating solvent stream to extend the useful life of a given quantity of solvent cycling through the solvent stream on the premises of use.
It is a further object of the present invention to provide an on-the-premises solvent recovery distillation plant employing a new and improved self-cleaning heating system which may be maintained without disturbing the remaining portions of the distillation apparatus to reduce or eliminate exposure of personnel to chemicals.
It is still another object of the present invention to provide an apparatus and method for conducting solvent distillation under conditions mild enough to avoid decomposition of solvent and solvent contents, so that non-volatile residues and impurities stripped from the solvent may be recovered intact, should. The NVRs be known or discovered to be separately useful or reusable.

On-site, controlled waste concentrator and solvent regenerator apparatus


Disclosed are a solar cell apparatus and a method for manufacturing the same. The solar cell apparatus includes a substrate; a back electrode layer on the substrate; a light absorbing layer on the back electrode layer; and a front electrode layer on the light absorbing layer, wherein an outer peripheral side of the back electrode layer is aligned on a plane different from a plane of an outer peripheral side of the light absorbing layer.

The embodiment relates to a solar cell apparatus and a method for manufacturing the same.
Recently, as energy consumption is increased, a solar cell has been developed to convert solar energy into electrical energy.
In particular, a CIGS-based cell, which is a PN hetero junction apparatus having a substrate structure including a glass substrate, a metallic back electrode layer, a P type CIGS-based light absorbing layer, a high-resistance buffer layer, and an N type window layer, has been extensively used.
In such a solar cell, the above layers are sequentially deposited on a back surface of the substrate and each layer may have a region having a deposition level different from that of other regions.
Therefore, the electric short may occur as a solar cell module is connected to an external device. In this case, the electric characteristics of the solar cell may be degraded.

Solar cell apparatus and method for manufacturing the same


A historical scenario and historical decisions made in the historical scenario are received. The historical decisions represent a set of decision variables of an objective function. A random set of decision variables having different values than the set of decision variables are generated. To determine a weight setting associated with multiple objectives of the objective function, a number of inequalities are built and solved with an assumption that, for an optimization that minimizes the objective function, the objective function having the set of random decision variables has a larger value than the objective function having the set of decision variables. The receiving, the generating and the building steps may be repeated to determine multiple sets of weight settings. The multiple sets of weight settings are searched to select a target weight setting for each of the multiple objectives. The target weight setting may be automatically and continuously learned.

The objective function of optimization models usually includes multiple components to achieve an optimal balance among multiple conflicting objectives such as to decrease cost versus to increase service level. Users often need to adjust the weights of objective components to meet different goals. The selection of weight settings helps in achieving the optimal and practical solution for a given set of business goals, but is a challenging task for a user, e.g., with little operation research background, given the highly abstract mathematical expressions.
The standard practice in the industry and academia is to set weights to an optimization function or model based on user experiences, intuition or through testing of different weight settings to determine the preferred weights. The selection of weight settings helps in achieving the optimal and practical solution for a given set of business goals, but is a challenging task for a user. The mathematical formulas built by operation research specialists may not be intelligible enough for users to set weights accurately purely based on their experiences or intuition, which may lead to sub-optimal impractical solutions. Further, testing of different weight settings can get time-consuming especially for a large scale problem.
The present disclosure describes a self-learning approach to automatically generate weight settings, for example, optimal weight settings, for a given set of goals.

Automatic learning of weight settings for multi-objective models

International Business Machines Corporation


One embodiment is a method that segments a bus topology to increase addressable devices that can attach to a bus. Switching occurs between different segments on the bus having multiple bus segments linked together.

Computer bus architectures can only support a limited number of attached nodes. For example, I2C (Inter-Integrated Circuit) buses use a 7-bit address space with 16 reserved addresses. These buses provide a maximum of 112 nodes that communicate on a same bus.
The use of I2C for system devices is reaching a stage where addressing concerns will limit the number of devices on the same bus. Such limitations will cause significant problems for systems requiring a large number of addressable devices.

Hewlett-Packard Development Company, L.P.


A folder provides easy access to its contents, is lockable, and keeps its locking mechanism out of the way when not in use. The folder has fold lines partway down on the front and back faces, so that the user has easy access to the folder contents. There is a gusset on the bottom edge and on the side edges from the bottom to the fold lines. The folder has an elastic member that is configured to act as a locking mechanism. In the locked position, the elastic member extends over the top edge of the folder, thereby preventing the front and back faces from being folded down and additionally preventing the folder's contents from escaping along the top edge. In the unlocked position, the elastic member extends over the side edges of the folder, and the user may optionally fold down the front and/or back faces and may access the contents through the top edge of the folder. The user can easily move the elastic member from a side edge to the top edge and back, to lock and unlock the folder. In both locked and unlocked positions, the elastic member lies flush along the exterior of the folder and does not dangle freely.

1. Field of the Invention
The present invention is directed to securable file folders.
2. Description of the Related Art
File folders are commonly used in office settings.
One type of folder is commonly known as an easy-access top tab file pocket. The folder has a gusset on its bottom and portions of its sides, which extend from the bottom to within about 7 cm from its top edge. The top of the folder is open. The front of the folder has a fold line close to the top of the gusset, so that the front may be folded down and the user may have easy access to the folder contents.
There are drawbacks to the easy-access folder described above. Although the folder is enclosed on the bottom and on most of the sides, the top of the folder is still open. If the folder is handled carelessly, the contents may escape, which is undesirable.
Another type of folder has a lock on its top edge, which can contain the folder contents if the folder is handled carelessly. Such a lockable folder is commonly known as an expanding wallet with an elastic cord. This folder has a gusset on its bottom and its complete sides, which extends to the top of the folder. The front of the folder is generally featureless. The back of the folder extends past the top edge of the folder and includes several fold lines, so that the folder back may be folded over the top of the folder and extend partway over the top portion of the front edge. The folded-over portion includes an eyelet, through which a loop of elastic material extends. The loop may be extended over the entire folder, along its front and back surfaces, generally centered between its left and right edges. When extended over the entire folder, the elastic loop locks the folder and keeps its contents intact, even when the folder is handled carelessly.
Despite the locking feature, the expanding wallet with elastic cord has drawbacks as well. In particular, when the folder is open, or unlocked, there is a large elastic loop that dangles from the folded-over portion of the back edge. This dangling loop is unwieldy, and is a nuisance.
Accordingly, there exists a need for a folder that provides easy access to its contents, is lockable, and keeps its locking mechanism out of the way when not in use.


A method, system and computer program product for dynamically routing messages in a publish/subscribe system. A messaging application receives messages from sensors (e.g., road condition sensors). Upon analyzing the messages using data analytics, an event (e.g., icy road condition) may be correlated with the analyzed messages. In such a scenario, a temporal topic based on the triggered event is created. Furthermore, a temporal publication (e.g., “icy road condition near exit 40”) and a temporal subscription are created. Potential subscribers to be associated with the temporal subscription are identified by using either geo-location information or social media information. Once those subscribers are identified, they are associated with the temporal subscription. The temporal publication is then published to the subscribers associated with the temporal subscription. In this manner, messages are dynamically routed to the appropriate subscribers that may have previously been excluded based on dynamically created temporal topics, subscriptions and publications.

A publish/subscribe system (or "publish-subscribe" system) is an effective way of disseminating information from "publishers" to multiple users or "subscribers." A publisher generates messages, also referred to as events, which contain a topic and some data content. A subscriber, also referred to as a "client," provides, ahead of time, a criterion, also referred to as a subscription, that specifies the information, based on published messages, that the system ("messaging system") is required to deliver to that subscriber client in the future. In a publish/subscribe system, publishers and subscribers are anonymous in that publishers do not necessarily know the number of subscribers or their locations; and subscribers do not necessarily know the locations of the publishers.
In the publish/subscribe system, subscribers typically receive only a subset of the total messages published. The messages may be selected for reception and processing using topic-based filtering. In a topic-based system, messages are published to "topics" or named logical channels. A topic may consist of multiple strings and wildcards. The publisher registers with a messaging application of the messaging system and defines the topics for the messages that will be published. For example, a publisher may publish messages pertaining to the soccer team of Manchester United (e.g., topic of "Sport/Soccer/ManchesterUnited"). A subscriber lists the topics of the messages (e.g., topic of "Sport/Soccer") the subscriber desires to receive ("subscription criterion"). The messages may be filtered by the messaging application using the subscription criterion which can be tested on each published message independent of any other message. For example, a filtered published message might be "topic=Sport/Soccer" for all messages related to the topic of soccer. As a result, the subscriber would receive messages published by the publisher pertaining to the soccer team of Manchester United.
Unfortunately, in the existing messaging systems, such topics are created statically. The topics are predefined and the messages are routed based on these predefined topics. As a result, important messages may not be effectively disseminated between the publishers and subscribers. For example, currently, there has been an increase in data being generated by sensors, mobile devices, etc. For instance, suppose a car accident was detected. The message pertaining to the car accident may be published to all the cars within a one mile radius of the car involved in the accident. However, since cars are moving and their geolocation coordinates are constantly changing, a static subscription and static publication system would not be able to inform those new drivers that are now within the one mile radius of the car accident after the initial publication of the message.

Dynamically routing messages in a publish/subscribe system by creating temporal topics for subscriptions and publications


A securing device composed of a plurality of components for a measuring apparatus used for determining the positions of two structural members which are movable relative to each other. The measuring apparatus includes a graduation, a carrier member carrying the graduation and a scanning device for scanning the graduation. The scanning device is guided at a constant distance from the graduation. The scanning device is fastened to one of the movable structural members by means of an assembly base. Spacer members are used for maintaining the securing device in an intended position relative to the carrier member. Each component of the securing device is a unit which can be separately attached to the carrier member. The components include interacting elements for connecting the components in a securing position.

1. Field of the Invention
The present invention relates to a securing device or lock device composed of a plurality of components for a measuring apparatus. The measuring apparatus is used for determining the positions of two structural members which are movable relative to each other. The measuring apparatus includes a graduation, a carrier member carrying the graduation and a scanning device for scanning the graduation. The scanning device is guided at a constant distance from the graduation. The scanning device can be fastened to one of the movable structural members by means of an assembly base. The assembly base is maintained by the securing device in its intended position relative to the carrier member by means of spacer members.
2. Description of the Related Art
Securing devices of the above-described type are particularly used for the transport and assembly of measuring apparatus in order to protect the sensitive structural members of the measuring apparatus and in order to enable the user to mount the measuring apparatus on a machine without problems. Generally, the securing devices are used by machine tool manufacturers.
A securing device of this type is disclosed in German Offenlegungsschrift 23 49 944 which is based on U.S. Pat. No. 3,833,303. An alignment arm is screwed to a beam and to a housing and serves to accurately position the housing relative to the beam and, thus, relative to a scale. Since screwed connections are used, the alignment arm can be used repeatedly.
Moreover, German patent 30 20 003 discloses a two-part securing device which is clamped by means of screws to the end faces of an assembly base of a hollow member and thereby secures the assembly base against accidental displacement.
The known securing devices have the disadvantage that the individual securing elements have to be screwed to the assembly base or to the hollow member.
It is, therefore, the primary object of the present invention to provide a securing device of the above-described type which is composed of simple components and can be easily assembled.


The present invention concerns a method at a wireless access point comprising a wireless interface, the method comprising the steps of enabling the wireless interface during a first period of time, checking if a wireless station associates during that first period of time, if a wireless station has been associated, keeping the wireless interface enabled, while a wireless station is attempting to associate, enabling the wireless interface during an extending period of time and if no wireless station is associated or is trying to associate, disabling the wireless interface for a second period of time.

This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
A centralized wireless network comprises a wireless access point and a plurality of wireless stations or client devices. Such a centralized wireless network is for example defined in the IEEE 802.11 family of standards. The access point is adapted to manage association of devices to the wireless network. The normal operational state of a wireless access point is to be active, even if no client devices are associated. The access point periodically sends beacon control packets to inform any station devices on the wireless network features. Being always active, the access point permits the station devices to associate. In a residential environment, the access point is generally idle for a main part of the day; no stations are associated, and no traffic other than beacon transmission occurs on the wireless network.
The access point consumes energy to manage a wireless network that is not used.


A heater device includes a pad that is heated by electrically heated fluid and which has areas for a user to insert his or her feet and areas for a user to insert his or her hands whereby either or both the user's feet and/or hands can be heated in an efficient manner.

1. Field of the Invention
The present invention relates to the general art of footwear, and to the particular field of protective footwear.
2. Description of the Related Art
In recent years, a great many people are engaging in outdoor sports such as skiing as well as many outdoor activities, including working. Those who engage in these activities are often exposed to the elements for extended periods of time. Such exposure can lead to discomfort or, more seriously, to frost bite particularly in the extremities. It is therefore vital that people who may spend a great deal of time outdoors seek protection from the elements in order to prevent the occurrence of exposure and frost bite.
The cooling of the extremities, has long been recognized as a serious deterrent to performing activities in cold temperatures and various proposals have been advanced for dealing with this problem. In the case of feet, most footwear known to the inventor, which has been designed for use in cold weather, has utilized hard and heavy materials on the sole and sometimes on the uppers as well. For instance, hard rubber soles are most commonly used for winter boots and overboots. Since such footwear is generally constructed with rigid sole structures, carrying and storing the footwear can be difficult.
Also, other footwear known to the inventor, designed for use in cold weather, has utilized conventional insulating materials, such as goose down, stiff insulating foam or synthetic fibers, to reduce the loss of heat from the wearer's foot. While these insulating materials attempt to minimize the heat loss from the wearer's foot, all of these insulating materials have various drawbacks.
A foot cover that is easy to manufacture, is easy to use, is lightweight, is easy to carry, is easy to store, is washable, and is highly effective at keeping the wearer's feet warm would be of considerable value.
A variety of other devices and methods are known for this purpose. For example, footwear can be provided with insulation or made waterproof. Such methods have significant drawbacks. For example, waterproofing methods provide no manner of either retaining heat or providing additional heat to the wearer's feet. Rather, they only prevent the introduction of water or other liquid, which could make the wearer's feet cold. Insulation is largely ineffective as well because it merely retains body heat without providing any additional heat.
One method of providing a heat source in footwear involves placing an electric heating element in the shoe or boot liner and using a battery to supply energy to the heating element. Another attempt to solve the problem of cold feet has involved the use of electrical heating elements in socks. Foot warming devices that use electric heating elements have a number of disadvantages. First and foremost, they can be dangerous. Specifically, they can create the risk of electric shock, sparks that could cause flammable socks and/or footwear materials to catch fire which in turn could burn the wearer's feet, and electrical shortages. Such electrical devices can also be expensive and inconvenient to use.
It is also known to adapt the insoles of boots, shoes and the like to accommodate a heat dispensing material in a pocket formed in the insole. These devices also have significant disadvantages. Specifically, they contemplate permanently modifying the footwear itself to accommodate the heat dispensing material. This could permanently add weight and bulk to the footwear which is unnecessary, especially when the footwear is worn in warm environments. In addition, these devices do not allow for adequate circulation of the generated heat to the wearer's feet.
Some prior art foot warmers include a removable insole for footwear that has a reduced thickness portion in the padding layer creating a cavity for holding a heat source that produces heat from an exothermic chemical reaction. These insoles often have an upper layer that has a plurality of holes for facilitating heat transfer from the heat source to the wearer.
Although an improvement, these insoles also have significant drawbacks. First and foremost, the heat source is generally enclosed in the cavity in such a way that the amount of air that can reach the heat source is limited. Thus, because the heat source needs oxygen to drive the chemical reaction necessary to generate heat, the amount of heat produced is greatly inhibited. The heat source is also enclosed in the cavity in such a way that the heat generated by the heat source cannot adequately circulate so that the wearer's feet are not effectively heated.
Still further, while a person's feet have received much attention in the above-described situations, a user's hands also may suffer the same problems when exposed to cold temperatures. While the inventor is aware of several devices that are intended to keep a user's hands warm, including gloves, mittens, heated gloves and mittens, the inventor is not aware of any device that can be used for either or both a user's feet and/or hands. Accordingly, a user is required to carry items for his or her hands as well as additional items for his or her feet. This can be cumbersome and inconvenient.
Therefore, there is a need for a device that can be used to heat a user's feet and/or hands.

Heater device for heating a user's hands and feet


An instrument for engaging a bone anchor may include a first implant engaging member having a proximal end and a distal end and a second implant engaging member having a proximal end and a distal end. The second implant engaging member may be integrally connected to the first implant engaging member by a pair of opposed integral spring members located proximal to the distal ends of the first and second implant engaging members. Manipulation of the proximal ends of the first and second implant engaging member can cause each of the distal ends to rotate about the pair of opposed spring members to engage at least a portion of a bone anchor. A rod adjusting tool may be connectable to the bone anchor engaging tool and may be axially adjustable relative to the bone anchor tool to adjust a spinal rod relative to the bone anchor.

Spinal fixation systems may be used in orthopedic surgery to align and/or fix a desired relationship between adjacent vertebral bodies. Such systems typically include a spinal fixation element, such as a relatively rigid fixation rod or plate, that is coupled to adjacent vertebrae by attaching the element to various anchoring devices, such as hooks, bolts, wires, or screws. The spinal fixation element can have a predetermined contour that has been designed according to the properties of the target implantation site, and once installed, the spinal fixation element holds the vertebrae in a desired spatial relationship, either until desired healing or spinal fusion has taken place, or for some longer period of time.
Spinal fixation elements can be anchored to specific portions of the vertebra. Since each vertebra varies in shape and size, a variety of anchoring devices have been developed to facilitate engagement of a particular portion of the bone. Pedicle screw assemblies, for example, have a shape and size that is configured to engage pedicle bone. Such screws typically include a threaded shank that is adapted to be threaded into a vertebra, and a head portion having a spinal fixation element receiving element, which, in spinal rod applications, is usually in the form of a U-shaped slot formed in the head for receiving the rod. A set-screw, plug, cap or similar type of closure mechanism, is used to lock the rod into the rod-receiving portion of the pedicle screw. In use, the shank portion of each screw is then threaded into a vertebra, and once properly positioned, a fixation rod is seated through the rod-receiving portion of each screw and the rod is locked in place by tightening a cap or similar type of closure mechanism to securely interconnect each screw and the fixation rod. Other anchoring devices also include hooks and other types of bone screws.
While current spinal fixation systems have proven effective, difficulties have been encountered in mounting rods into the rod-receiving portion of various fixation devices. In particular, it can be difficult to align and seat the rod into the rod receiving portion of adjacent fixation devices due to the positioning and rigidity of the vertebra into which the fixation device is mounted. Thus, the use of a spinal rod approximator, also referred to as a spinal rod reducer, is often required in order to grasp the head of the fixation device and reduce the rod into the rod-receiving portion of the fixation device.
While several rod approximators are known in the art, some tend to be difficult and very time-consuming to use. Accordingly, there is a need for an improved rod approximator and methods for seating a spinal rod in a rod-receiving portion of one or more spinal implants.

Instruments and methods for bone anchor engagement and spinal rod reduction


A model eye includes an optically transmissive structure having a front curved surface to receive a coherent light beam, and an opposite rear planar surface for directing a portion of the coherent light beam back out the model eye through the front curved surface; and a material structure adhered to the rear planar surface of the optically transmissive structure that has a characteristic to cause a speckle pattern of the portion of the coherent light beam that is directed back out the front curved surface of the optically transmissive structure to have a bright-to-dark ratio of less than 2:1. In some embodiments, the material structure may include a fabric-reinforced polyethylene tape adhered to the rear planar surface of the optically transmissive structure by an adhesive. One example material structure which may be employed is duct tape.

1. Field
This invention pertains to optical measurement equipment, and more particularly for a model eye for verifying proper operation and performance of optical measurement equipment, and a method for verifying proper operation and performance of optical measurement equipment with a model eye.
2. Description
There are a number of optical measurement or analysis instruments which utilize one or more light spots generated from coherent light sources, such as lasers or superluminscent laser diodes (SLDs), to make optical measurements of the eye. Well-known examples of such instruments include wavefront aberrometers (e.g., Shack-Hartmann wavefront aberrometers) and corneal topographers.
An undesirable feature of these light sources is that the light pattern produced in the instrument is marred by speckle. Speckle is a spotty pattern with large light intensity variations. FIG. 1 illustrates an example of a speckle pattern. Speckle is caused when the layer from which the light is scattered is thinner than the coherence length of the light source. A typical SLD has a bandwidth of thirty nanometers, which corresponds to a coherence length of one hundred microns.
Speckle can cause problems with some optical measurement or analysis instruments. For example, there are two ways that speckle causes measurement errors in an instrument that employs a Shack-Hartmann wavefront sensor. One problem is that the mathematical algorithms called reconstructors that are employed by such instruments have fitting errors in data sets that contain dark regions of the speckle pattern. Another problem is "intensity coupling." Intensity coupling may occur when a wavefront sensor is constructed such that the lenslet array is not located exactly one focal length from the pixel array. In that case, intensity variations cause shifts in the spot locations that are independent of the slope of the wavefront. These shifts cause errors in the calculated wavefront.
With the human eye, speckle is mitigated because the scattering occurs in a volume that has a thickness that is longer than the coherence length of the light source. The light penetrates into a layer of the eye and weak scatter occurs throughout the volume. As a result, when an SLD light source illuminates a human eye, the bright-to-dark ratio is typically about two to one.
Meanwhile, it is sometimes necessary to be able to verify correct operation and specified performance of an optical measurement instrument such as a wavefront aberrometer in an operational setting. In many instances, this is done by operating the measurement instrument to make a measurement of a model eye whose characteristics are known. In that case, typically the optical measurement instrument injects a probe beam into a front surface of the model eye. Light scatters from the back surface of the model eye similarly to the way it does with a human eye, and some of the scattered light travels back out of the front surface and into the optical measurement instrument.
However, when a typical model eye is measured, the speckle is more severe than is typically seen with a human eye. The problem is made even worse by the fact that the "cornea" of the model eye acts like a magnifying glass and makes the structure of the bright spots and dark regions appear large on the detector inside the optical measurement instrument. The typical speckle pattern for a model eye has a bright-to-dark ratio of twenty-to-one, which is about an order or magnitude greater than for a human eye. These large variations in light level make for inaccurate measurements, for the reasons explained above.
Therefore, it would be desirable to provide a model eye which produces a speckle pattern exhibiting a reduced bright-to-dark ratio.
In one aspect of the invention, a method comprises: providing a model eye comprising an optically transmissive structure having a front curved surface and an opposite rear planar surface, and a material structure adhered to the rear planar surface of the optically transmissive structure; directing a coherent light beam through the front curved surface of the optically transmissive structure to the opposite rear planar surface; receiving at a measurement instrument a portion of the light returned from the rear planar surface of the optically transmissive structure, wherein the material structure has a characteristic to cause the light received by the measurement instrument from the rear planar surface of the optically transmissive structure to have a speckle pattern with a bright-to-dark ratio of less than 2:1.
In another aspect of the invention, a model eye comprises: an optically transmissive structure having a front curved surface configured to receive a coherent light beam and an opposite rear planar surface for directing a portion of the coherent light beam back out the model eye through the front curved surface; and a material structure adhered to the rear planar surface of the optically transmissive structure and having a characteristic to cause a speckle pattern of the portion of the coherent light beam that is directed back out the front curved surface of the optically transmissive structure to have a bright-to-dark ratio of less than 2:1.
In yet another aspect of the invention, a model eye includes: an optically transmissive structure having a front curved surface and an opposite rear planar surface; and a fabric-reinforced polyethylene pressure-sensitive tape with a semi-flexible shell adhered to the rear planar surface of the optically transmissive structure by a pressure sensitive adhesive.

Model eye producing a speckle pattern having a reduced bright-to-dark ratio


A magnetic tape cassette having a guide pole which is in sliding contact with the magnetic surface of the tape produced in such a manner as to improve the running characteristics of the tape while being capable of being manufactured at a low cost. A cylindrical stainless steel base member is subjected to a barreling treatment so as to secure fine particles of an inorganic material having a Moh's hardness of greater than 9 to the slide surface of the guide post. Moreover, the surface of the guide pole can be finished by a surface rolling to reduce the number of scratch-like grooves in the slide surface having a depth of more than 0.2 .mu.m and a width of less than 40 .mu.m to less than 11 per millimeter in the sliding direction of the tape.

The present invention relates to a magnetic tape cassette, particularly, to a magnetic tape cassette used in a VTR (video tape recorder) or the like.
A variety of magnetic tape cassettes, including those of the Beta and VHS type, are known for use in VTRs or the like. The conventional cassettes all employ the same basic structure. FIG. 1 shows, as an example, a cassette of the VHS type. The magnetic tape cassette of FIG. 1 includes a tape guiding structure such as cylindrical tape guides 13, a guide pole 14, a guide roller 15, and a pressure pad 16 which cooperate to guide a magnetic tape T in running between a supply reel 11 and a take-up reel 12.
The sliding characteristics of the magnetic tape on these guide members greatly affect the tape running characteristics. This can be readily understood from the fact that the magnet tape T is manufactured by forming a magnetic layer on a flexible film support made of acetate, polyester, or vinyl chloride, as is well known in the art. To increase the total recording and playing time of the tape, or to improve the electromagnetic properties of the tape, a thinner tape having a high surface smoothness has been developed.
To take advantage of the improved sliding properties of such a tape, it is necessary to improve the surface smoothness of the above guide members. That is, as the thickness of the magnetic tape is reduced, its rigidity is decreased, and therefore the running characteristics of the tape are more strongly affected by the guide members. In the case of a tape used for recording and reproducing data at a high recording density, even slight variations in the behavior of the magnetic tape can strongly affect the recording and reproducing operations carried out with the tape. For example, variations in the behavior of the tape running can result in a jitter phenomenon, making the reproduced picture waver in the horizontal direction. Accordingly, it is essential to make the tape run smoothly.
The inventors have conducted intensive research into the above-described problems and found that variations in the running characteristics of the tape are largely attributable to the guide members which are in contact with the magnetic layer of the tape, namely, the guide pole 14 as shown in the example of FIG. 1, and to the surface characteristics of the tape itself. For instance, a tape with a magnetic surface having an Ra value of less than 0.01 .mu.m (cut-off value of 0.25 mm) is more likely to have adversely affected tape running characteristics.
Thus, the above-described drawbacks may be eliminated with the provision of a guide pole 14 (with which the surface of the magnetic layer of the tape is brought into contact) which is made harder than a conventional guide pole and which is polished or subjected to other surface treatment so as to improve its surface smoothness. On the other hand, such techniques significantly increase the manufacturing cost of the guide pole, making the guide pole impractical for ordinary manufacturing use.

Magnetic tape cassette having improved guide pole structure


Embodiments of the invention provide a bioreactor chamber assembly comprising: a bioreactor chamber comprising first and second portions arranged to be coupled to one another thereby to provide a liquid-tight seal therebetween; a pair of clamp members; and a pair of resilient loop elements, wherein the clamp members are arranged to sandwich the chamber between the clamp members and the loop elements are arranged to apply a force between the clamp members to urge the first and second portions together.

It is known to provide a bioreactor having a culture chamber and means for passing a flow of culture medium through the chamber in order to enable a wide range of studies of biological materials. By way of example, the biological material under investigation may be a monolayer cell culture, scaffold culture or tissue slice. WO2005/123258 discloses a bioreactor for studying the effects of imposed stimuli on cellular activity.


A liquid discharge device is configured to display, on a display, an S_Empty notification screen in a state where a low level signal is not received from a liquid level sensor and a count value SN2 reaches a second threshold value Nth2. The liquid discharge device is configured to erase the S_Empty notification screen in a state where the low level signal is received after receiving a high level signal is received from an installation sensor.

From the related art, an inkjet printer is known (for example, JP-A-2008-213162) which includes a detachable main tank, a sub tank that stores ink supplied from the installed main tank, and an image recording unit that discharges the ink stored in the sub tank and prints an image. In the inkjet printer having the above configuration, internal spaces of the main tank and the sub tank are opened to the air. For this reason, when the main tank is installed in the inkjet printer, the ink moves due to a water head pressure so that the liquid level of the main tank and the liquid level of the sub tank are aligned with the same height by the difference between a water head in the internal space of the main tank and a water head in the internal space of the sub tank (hereinafter, referred to as "water head difference"). Then, when the residual amount of the ink detected by a residual amount detection sensor is less than a threshold, the inkjet printer displays the fact that the ink is empty, or prohibits the discharge of ink through the recording unit.
In the inkjet printer, when the ink is stored in the sub tank as much as air does not enter an ink flow path extending from the sub tank to the image recording unit, the ink discharge of the image recording unit is prohibited. Thus, a so-called air-in, in which the air enters the flow path, can be prevented in the inkjet printer.
When the main tank is exchanged, ink flows out from the main tank to the sub tank. If a residual amount detection sensor for detecting the ink is provided in the sub tank, the ink flows from the main tank to the sub tank, and eventually, the detection signal of the residual amount detection sensor changes. When the detection signal of the residual amount detection sensor changes, it is possible to erase the indication of the empty on the display and to cancel the prohibition of the discharge of the ink. However, when the ink flows out from the main tank to the sub tank and the time is required until the signal output from the residual amount detection sensor changes, the empty indication on the display does not disappear during that time, whereby a user may be kept waiting until the image recording is performed.


A linear actuator is provided. The linear actuator comprises: a body; a shaft adapted to move linearly relative to the body; a driver adapted to drive the linear movement of the shaft; and a shape memory alloy component configured to compensate for thermal expansion or contraction of the linear actuator due to a change in temperature thereof.

Such actuators typically include an output shaft and a position feedback control system. When used in aircraft or other high integrity servo systems, any expansion or contraction of such actuators due to thermal effects will alter the position of the output shaft when actuated, adversely affecting the position accuracy achieved.
To compensate for the adverse effects of such expansion or contraction, the position feedback control system can be utilised. For example, in an electromechanical linear actuator for actuating a trailing edge flap on a helicopter blade, a feedback system may be provided which measures the position of the trailing edge flap, determines any error in the position of the trailing edge flap and causes the output shaft of the electromechanical linear actuator to move by a desired amount to correct for the error in the position of the trailing edge flap.
While such a feedback system may provide satisfactory operation, the feedback control system can be complex. For example, an additional signal may be required for temperature measurements. This may add complexity to the control algorithm used, resulting in higher costs, size and weight of the linear actuator. In the aerospace industry at least, there is a desire to reduce the size and weight of components used. A reduction in the cost and complexity of components is also desirable.