A method providing quality of service during a contention period. A tiered access protocol enables an Access Point to act as a channel arbitrator and gain control a channel during a contention period. The Enhanced Access Point waits a specified amount of time after before taking control of a channel for either transmitting an outbound frame or initiating Polled-Contention Free Bursts. In addition, a method for increasing the time span between Delivery Traffic Indication Message beacons by tracking when Wireless Stations are able to receive messages and instantly delivering messages to those Wireless Stations.

1. Field of the Invention
The present invention is directed to channel access methods that provide Quality of Service ("QoS") for shared communications, more specifically to channel access methods that provide Quality of Service on IEEE 802.11 wireless networks.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
The abbreviations and acronyms used in this application are well known to those skilled in the art and can be readily located in the IEEE 802.11 standard, or in the IEEE 802.11E QoS baseline proposal. See Michael Fischer, QoS Baseline Proposal, IEEE 802.11 Standards Committee, Document IEEE 802.11-00/360 (Nov. 7, 2000); also QoS Baseline Proposal Revision 1, Document IEEE 802.11-00/360R1 (Nov. 7, 2000) and QoS Baseline Proposal Revision 2, Document IEEE 802.11-00/360R2 (Nov. 9, 2000), the contents of which are hereby incorporated by reference. Some of the abbreviations and acronyms used in this application are:
ACKAcknowledgement;APAccess Point;BSSBasic Service Set;BSSIDBasic Service Set Identification;CCAClear Channel Assessment;CFPContention-Free Period;CF-PollableContention-free PollableCPContention Period;CWContention Window;DCFDistributed Coordination Function;DIFSDistributed (coordination function) Interframe Space;CWContention Window;DTIMDelivery Traffic Indication Message;EAPEnhanced Access Point;IFSInterframe Space;MACMedium Access ControlNAVNetwork Allocation Vector;PCFPoint Coordination Function;P-CFBPoint-controlled Contention-free Bursts;PIFSPoint (coordination function) Interframe Space;QoSQuality of Service;SBMSubnet Bandwidth Manager;SIFSShort Interframe Space;STAStation;V-DCFVirtual Distributed Coordination Function;WSTAWireless (enhanced) Station.
In the description that follows, an "outbound" transmission is a transmission from an AP and an "inbound" transmission is directed to an AP. FIG. 2 illustrates the relationship between a SIFS, PIFS and DIFS as used herein and as defined in the 802.11 specification. As can be observed from FIG. 2, a SIFS is always a shorter interval than a PIFS, and a PIFS is always a shorter interval than a DIFS.
The IEEE 802.11E QoS working group has adopted a baseline proposal (hereinafter "baseline proposal") for channel access methods that provide QoS on 802.11 wireless LANs. The baseline proposal defines three QoS levels—a "prioritised" DCF-based solution and "prioritised" and "parameterised" PCF-based solutions. It is generally agreed that a single unified approach is better from a user perspective; however, no single approach, as it is currently defined, is applicable to all environments. A PCF approach is more deterministic and efficient in single-BSS environments; however, it is difficult to implement a CFP scheduling algorithm in environments with BSS overlap. The present invention is directed to an integrated DCF/PCF channel access model that uses V-DCF for lightly and moderately loaded channels, and dynamically uses unscheduled "Point-controlled Contention-free Bursts", to arbitrate channel contention, as the network load increases.
The baseline "prioritised" solutions are intended for stations that simply send and receive prioritised frames. The baseline "parameterised" solution is intended for WSTAs that use a signaling protocol to establish bandwidth requirements and delay constraints. This invention, the Point-controlled Contention Arbitration model, or PCCA model, requires all WSTAs to implement sufficient channel access and interface functions to support optional parameterised services. QoS features can be added to an AP implementation on an incremental basis.
The baseline proposal discloses a virtual DCF protocol ("V-DCF). By design, the V-DCF, or level 1 in the baseline proposal, cannot provide integrated services such as "Controlled Load" and "Guaranteed Bandwidth". Two fundamental requirements are lacking for controlled load service. 1) The total traffic at a given QoS priority must be limited (i.e. by admission control), and 2) higher priority traffic cannot be affected by lower priority traffic. The V-DCF level cannot support admission control because it lacks even a simple signaling protocol. The V-DCF access method, with contention offset and CWmin values per category, only statistically increases the probability of channel access for higher-priority packets. A tiered channel access method can be used to isolate a high-priority traffic category but only if the idle sense time, required for any lower-priority traffic category, is greater than the sum of the idle sense time plus the maximum CW value for the high-priority category. However, the tiered method doesn't scale well for large high-priority populations. "Guaranteed Bandwidth" service has the same requirements as controlled load and also requires a deterministic channel access method.
Presently, 802.11 networks use two protocols, the DCF and PCF. The DCF works great under low load situations. The PCF works optimal under high load conditions. The DCF works better in networks where BSSs overlap, the PCF is ideally suited for networks where BSSs are carefully planned not to overlap. The DCF has a relatively low implementation complexity, the PCF is reputed to be more complex to implement. The DCF does not allow explicit access control, the PCF does. The DCF efficiency drops considerably in densely populated BSSs, the PCF has no scaling problem.
Due to the inability of the PCF to work well under overlapping BSS conditions and the high implementation complexity, the PCF has not yet been widely adopted in current 802.11 implementations. The demand for better medium efficiency and a versatile QoS platform, however, increased interest in this optional access mechanism of the 802.11 MAC.
The hybrid nature of the 802.11 MAC has caused proposals to focus either on the DCF or the PCF. However, by only looking at the PCF and not considering the DCF overlooks the fact that the 802.11 MAC always spends some time under the DCF access mechanism rules and that the DCF is also an integral part of a PCF based system. The system always has to spend at least a small part of its time under the DCF. The PCF has the fundamental characteristic that a station can't access the medium unless explicitly polled. However, to be polled, the station must first make itself known to the Point Coordinator, which requires medium access. Therefore, a PCF based solution must support both contention-free and contention periods. A contention period is required for bursty traffic, adjacent BSSes, probe requests, association and re-association requests, etc.
FIG. 1 shows an example of a sample rate for a real-time application in a WSTA and the associated polling sequences for that WSTA. The lower portion 12 of FIG. 1 shows the WSTA sample rate. The upper graph 14 shows the polling sequences. The polling sequence starts with a DTIM beacon 16. The contention-free period 18 starts immediately after the DTIM beacon 16. During the contention-free period 18, the point controller initiates polling sequences 20. After the polling sequences 20 is shown an idle time period 22. The idle time period 22 is then followed by an additional polling sequences 20 and idle time periods 22. Following the contention-free period 18 is the contention period 24. After the contention period 24, another DTIM beacon 16 starts a new sequence of a contention-free period 18 and a contention period 24.
In FIG. 1, the DTIM beacon rate is slower than the sampling rate. Idle time 22 is introduced if the CFP is extended so that the same WSTA can be polled more than once per CFP. Latency is introduced if the channel is overloaded in the contention period.
Delay sensitive applications, such as VoIP, require short DTIM intervals (i.e. 30 milliseconds) to minimize CF polling latency. A fast DTIM beacon rate wastes bandwidth because of the beaconing overhead and because contention-based transmissions cannot span the TBTT (per the baseline proposal). A fast DTIM beacon rate also requires power-save WSTAs to wake up more often, for example to receive multicast frames and buffered unicast frames.
In installations with multiple QoS applications with different service rates, the DTIM beacon rate cannot match the sampling rate for each application. Actually, it is difficult to match the sampling rate for any application. It is not efficient to arbitrarily poll WSTAs in every CFP. Therefore, some sort of signaling protocol is necessary to suppress unnecessary polls. In addition, a need exists for a protocol that can divorce the service rate, for active parameterised stations from the beacon rate. Periodic polling is not optimal for intermittent traffic. VoIP traffic can be intermittent due to silence suppression.
Depending on the 'load of the medium', the system may spend more or less time in the CFP. In a heavily loaded system, the system may spend the larger part in the CFP while a mildly loaded system may spend the larger part in the CP. The balance between the two access mechanisms is a function of the medium load. As a consequence, both access mechanisms must provide the same QoS capabilities. The transition between one access mechanism and the other must be a smooth one. This is especially a challenge in average loaded systems where the DCF efficiency is starting to breakdown while the PCF efficiency is not yet optimal. For the upper layer protocol (or application) the performance profile of the service should be linear over all medium conditions and this is something that should be considered when proposing a PCF based system. Therefore, when proposing PCF enhancements, one also to consider the interaction between the PCF and the DCF and the dynamics of the system as a whole under various medium load conditions.
PCF combines the ability of full medium control with optimal medium efficiency, without suffering from scalability problems. However, there are two issues that limit the use of the current PCF for QoS systems. Section 9.3.4 and specifically clause 18.104.22.168 of the IEEE 802.11 standard imposes strict rules upon the order in which stations are addressed or polled. This is undesirable in a QoS system. Secondly, there is no mechanism, other than the More-Data bit, that allows a station to communicate its queue states to the PC.
The entity in the PC that actually calculates the order in which stations are addressed is in literature often referred to as the 'scheduler'. The rules for the handling of the polling list limit the freedom of the scheduler and may conflict with QoS requirements. The original intent to poll stations in order of ascending AID value is not clear from the standard and in fact the whole concept of a polling list may become obsolete due to the introduction of a mechanism for communicating To-DS queue state(s). Therefore, the rules as defined in section 9.3.4 are neglected for this method.
In order to make accurate scheduling decisions, the scheduler in the PC needs to have knowledge about the queues in the associated stations. The More-Data bit is a Boolean that could be used for this but only allows communication of a truth-value on the queue state; for a good scheduler implementation this is not enough. Preferably, the scheduler needs to know the length and priority of the next frame in the queue of each station.
Scheduling problems arise with CFPs in networks with overlapping BSSes in the same ESS or multiple ESSes. A CFP is not completely contention-free unless all stations in any neighboring BSS, that are in range of any active stations in the BSS, set their NAV for CFPMaxDuration for the CFP. Therefore, the total "reservation area" for a CFP can be very large compared to the coverage area of the point controller for the BSS.
The baseline proposal defines a "proxy beacon" mechanism where WSTAs in a BSS repeat AP beacons to extend the area for propagating beacon information to hidden nodes. The baseline proposal does not define which WSTAs should send proxy beacons and it does not define the scheduling mechanism for proxy beacons. Also, it is not clear whether a hidden node in a neighboring BSS, that receives proxy CFP beacons, should set its NAV for CFPMaxDuration for the TBTT of the associated hidden CFP. If hidden nodes do not set their NAV for proxy beacons, then CFPs are not contention-free.
If hidden nodes set their NAV for CFPMaxDuration for a hidden CFP (due to proxy beacons or some other mechanism) then two difficult problems must be considered. First, as noted above, spatial reuse is severely inhibited as compared to DCF. The baseline proposal attempts to solve the "spatial reuse" problem by classifying WSTAs as belonging to overlap and non-overlap sets per BSS. However, that approach does not work for all applications because it assumes that a WSTA is relatively stable compared to its transmission rate and it uses the flow error rate as an overlap indicator. Second, if a hidden CFP ends early, then bandwidth is wasted because hidden nodes may not be able to determine that the hidden CFP has ended. It has been suggested that WSTAs that transmit proxy beacons could also transmit "proxy CF-End" messages or CF-End messages could be transmitted on the distribution system. The first solution is "chatty" and the second solution is not generally applicable because the distribution system may introduce latency (i.e. if it includes wireless links or IP tunnel links).
It should also be noted that in the PCF/CFP model, where the NAV is set for long CFPs, use of sophisticated techniques that increase spatial reuse by varying the transmit power and/or antenna direction per unicast transmission sequence is inhibited.
One suggested PCF enhancement that can ease the overlapping BSS problem and alleviate the scheduling problem is the Contention Free Burst. A paper entitled "Suggested 802.11 PCF Enhancements and Contention Free Bursts", IEEE 802.11-00/113 (May 10, 2000), written by Maarten Hoeben and Menzo Wentink, hereby incorporated by reference, describes bi-directional contention-free bursts that include point controller polling.
The Contention Free Bursts concept breaks up a Contention Free Period into smaller Contention Free Bursts. This is useful for two reasons: First, it allows the PC to relinquish medium control to other BSSs in the same area. Second, in the case of average loaded systems, the PC can temporarily give-up medium control (to possibly another BSS) and defer control until new frames are available for transmission.
Normally, a CFP starts with the transmission of a Beacon. A SIFS after the Beacon, the first CFB is started. Within the CFB, the PCF transfer procedures apply as defined in section 9.3.3 of the IEEE 802.11 standard. CFBs have a maximum duration of CFBMaxDuration. The duration remaining in the CFB is encoded in the Duration/ID field of every From-DS frame sent by the PC. The CFB may be foreshortened but never lasts longer than CFBMaxDuration. The end of a CFB is signaled through a duration of 0.
Between two CFBs the PC performs a random backoff, selected from a range of 0 to CW-1 slots. The random backoff mechanism allows PCs to contend for the medium to start a new CFB. In the current definition of the CFP, all stations (including other access points) set their NAV based on the Duration Remaining field in the CF-Parameter set and reset the NAV upon receiving a CF-End. This prevents access points and stations from accessing the medium during observed medium idleness during the CFP (possibly caused by the transmission of a frame by a hidden node). PCs may use the backoff mechanism to contend for the medium and start a CFP or continue their own CFP with a new CFB. In a sense the CFB concept works like a superimposed DCF over the PCF. PCs coordinate their bursts by using the backoff-mechanism, deferring and restarting the backoffs whenever a PC starts a CFB or ends the CFB. The CFBs are protected through the NAV-alike duration field in the redefined in Duration/ID field, CPs use the information as received in the ToDS frames from other CPs to update their CF-Nav and defer backoff and start of a new CFB.
Note that only PCs contend for medium control; stations (and legacy access points) do not attempt to access the medium during the periods of medium silence caused by the backoff periods because they adhere to the Contention Free Periods of (at least one of) the BSSs. A CFB is furthermore protected from interference of legacy implementations due to the SIFS/PIFS interframe spaces, and a Duration/ID field that is interpreted as a very long NAV.
Another concern is that PCF and DCF applications do not always coexist well. The PCF model only supports "polled" inbound transmissions during a CFP. As a result long PCF-based CFPs can starve DCF-based stations. The problem is exacerbated when CFPs in overlapping BSSes must be scheduled to avoid CFP contention. PCF polling is appropriate for isochronous applications, but DCF is more appropriate for asynchronous data. It should not be assumed that PCF polling is used for all high-priority inbound transmissions; however, the current baseline model inherently prioritizes PCF over DCF. As an example, consider inbound asynchronous high-priority network control transmissions. Such transmissions can be delayed extensively by lower priority PCF transmissions.
The current 802.11 standard specifies that an AP must buffer all outbound multicast frames and deliver them immediately following a DTIM beacon if "strict ordering" is not enabled, then. Therefore, short DTIM intervals are necessary to support multicast applications that cannot tolerate delays. In addition, outbound multicast transmissions are more susceptible to problems associated with inter-BSS contention and hidden nodes because multicast frames are not retransmitted (i.e. after a collision with a hidden node) and the DCF channel reservation mechanisms cannot be used for multicast frames.
The baseline proposal removes the restriction that buffered multicast/broadcast frames must be sent immediately following a DTIM beacon. The baseline proposal requires that QoS WSTAs must respond to +CF-Polls. Therefore, it is strongly recommended that QoS stations should also associate as CF-Pollable (i.e. not requesting to be polled). If QoS power-save WSTAs do not use the PS-Poll mechanism for the delivery of outbound buffered messages, an AP can more easily schedule outbound transmissions for PS WSTAs. Note that CF-Pollable stations do not send PS-Poll frames to solicit outbound transmissions. Instead, a CF-Pollable station must stay awake, after it receives a DTIM beacon with its AID bit set on, until either it receives a unicast frame with the more bit set off, or a TIM with its AID bit set off. Therefore, it is generally assumed, but not required, that QoS WSTAs with active flows will operate in active mode because a point controller cannot successfully poll a WSTA that is in power-save mode.
The baseline proposal defines "awake-time epochs" that can, optionally, be used to set an awake-time window for periodic polling and/or outbound data transmissions. However, awake-time epochs introduce complexity for P-CFB polling and PCF polling. If power management must be supported, it would be simpler to schedule P-CFB polls for power-save parameterised WSTAs, if such WSTAs used automatic power-save intervals. Such a power-save WSTA can remain in power-save mode for, at most, the duration of its "automatic power-save interval", following an inbound transmission, where the duration is selected to match the WSTAs inbound transmission rate. The point controller can simply adjust the duration of the poll timer, for a WSTA, so that it is greater than the sleep-time window duration. The point controller can then poll a WSTA and/or deliver outbound buffered data for a WSTA when the poll timer expires.
Therefore, for the reasons set forth above, there is a need for a contention-based channel access method for supporting parameterised QoS applications. Furthermore, the channel access method must coexist well with PCF and DCF applications.

Point-controlled contention arbitration in multiple access wireless LANs


A gas turbine airfoil (10) includes a pressure sidewall (12) and a suction sidewall (14) joined along respective leading (16) and trailing edges (18) and extends radially outward from a root (20) to a tip (22). The airfoil also includes a trailing edge corner (24) comprising a metering hole (36) receiving a cooling fluid flow (26) from an interior fluid flow channel (e.g., 32) and discharging a metered flow (40). A dispersion cavity (42) receives the metered flow and discharges a dispersed flow (44). The dispersion cavity includes a cross sectional area (46) greater than a cross sectional area (48) of the metering hole. An open flow channel (52) receives the dispersed flow and conducts the dispersed flow to a periphery (54) of the airfoil, the open flow channel controlling mixing of the cooling fluid flow with a process gas (e.g., 28) flowing around an exterior (34) of the airfoil.

Gas turbine airfoils exposed to hot combustion gases have been cooled by forming passageways within the airfoil and passing a cooling fluid through the passageways to connectively cool the airfoil. Such cooled airfoils may include a serpentine, multiple-pass flow path to provide sufficient convective cooling to maintain all portions of the airfoil at a relatively uniform temperature. In addition, the cooling fluid flow may be allowed to exit an interior of the airfoil at desired locations to provide film cooling of an external surface of the airfoil. One of the problems facing designers of airfoils exposed to hot combustion gases is that the airfoils need to be sufficiently strong to withstand forces applied to it during operation of the gas turbine, yet still retain an ability to be cooled effectively to prevent thermal fatigue. Reducing an amount of material used to form the airfoil, such as by making airfoil walls thinner, may reduce an amount of a cooling fluid flow required, but using less material to form the airfoil may adversely reduce a strength of the airfoil. Conversely, increasing an amount of material used to form the airfoil may make the airfoil stronger, but reduce the ability of the airfoil to be cooled sufficiently to prevent thermal fatigue. Furthermore, it is generally desired to keep the trailing edge of the airfoil relatively thin to achieve a desired aerodynamic efficiency. However, a thin trailing edge may increase the likelihood of failure of the trailing edge, for example, under the high centrifugal stresses imposed on it during turbine operation.

Gas turbine airfoil trailing edge corner


An ultra-heavy mail piece processing system first collects the data to be printed out and then formats the data for printing. A rendering process then determines how the mail piece will be printed. Based on the total number of pages in the mail piece, the system will direct mail pieces having a total number of pages equal to or greater than an upper bound to an ultra-heavy handling process. The data stream for each ultra-heavy mail piece is split into a data stream for the first page and a data stream for all the second pages for the mail piece. The data stream for each first page is sent to a printer for printing in one-up format. The data stream for each set of second pages is reformatted to allow the data stream for each set of second pages to be sent to and printed on a different printer from the first printer in a two-up format. After each of the first pages and each set of second pages are printed, the first pages are manually collated with their corresponding set of second pages, and each mail piece is then manually packaged up and the proper postage is applied for mailing.

This invention relates to mail piece processing and more particularly, to processing mail pieces that have a first page that is a different size than any additional second pages. Even more particularly, the invention relates to processing mail pieces with a first page that is a different size than any additional second pages that exceed a certain number of total pages differently from mail pieces that do not exceed a certain number of total pages.
Many businesses, political, and charitable organizations rely on mass mailings to communicate with their constituents or customers. Certain of these mailings, especially those related to billing, may entail large numbers of pages. For example, long-distance telephone service companies and regional telephone companies may produce bills for mailing to their customers that entail numerous pages of detailed information regarding local and long distance phone calls made by the customer. Also, credit card companies which service large accounts, such as corporate accounts, may also generate bills for mailing that have numerous pages detailing various charges on the account. Hospitals may also produce billings to their customers involving numerous pages of detailed billing information.
Producing these bills for mailing on a timely basis is both a necessary and vital business function. In many cases a business""s best customers often receive the largest bills. These customers also typically demand their bills to be of a high quality on cleanly cut paper. Once received by the customer, the bills are often copied and distributed within the company. Producing bills for mailing to these customers in a timely fashion and with high quality is difficult to do. Thus, the best customers for a business often get the poorest service in relation to receiving their bills in a timely fashion because of their large number of pages and the high quality that is required.
Many efforts have been made to assist businesses and organizations having these large mass mailings to be able to gather the data, process the data, and print the data in as fast and accurate and economical a manner as possible.
In some businesses that produce these large mass mailings, and particularly related to billing, the first page of the bill is printed on a different size sheet of paper than the subsequent detailed sheets. The first page often has a tear-off stub portion that the customer returns with their payment for the bill. This type of bill format introduces even more problems in efficiently processing, formatting, printing, and mailing out bills to customers. example, there are mail piece handling machines that are designed to work in conjunction with a printer to automatically fold the printed bill, add inserts, stuff the bill and inserts into an envelope, seal the envelope, and apply the proper postage for mailing. However, most of these machines have a limit as to the number of pages they are able to handle. Typical upper limits on such mail piece handling machines range from between eight to ten pages total. Once this upper bound has been exceeded, then a different process must be used to handle the bills. These bills, which have more pages than the automatic processing system can handle, and are referred to as heavy bills. Normally, processing these heavy bills entails some amount of manual labor in order to match the first cover page of one size with the corresponding second pages of a different size, merging the two together for mailing, and then applying the proper postage. Experience has shown that the more second pages there are in a heavy bill, the more inefficient the whole process becomes.
There is a need in the art to ensure that bills that have a large number of pages are sent to customers on a timely basis through more efficient processing. There is also a need in the art to reduce the amount of manual labor spent in processing bills that have a large number of pages. There is a further need in the art to ensure that bills that have a large number of pages are of a high quality, are printed in less time, and at a reduced cost.
Thus, it is an aspect of the present invention, in mail pieces where the first page of the mail piece is a different size than any second pages of the mail piece, and when the total number of pages in the mail piece is greater than a predetermined upper bound, to process the data stream for the mail piece differently than the data stream for mail pieces that have a total number of pages less than the upper bound.
Yet another aspect of the invention is to split the data stream for a mail piece having total pages greater than a predetermined upper bound into a data stream for the first page and a data stream for the remaining second pages.
Still another aspect of the invention for a mail piece having total pages greater than a predetermined upper bound is to send the data stream for the first page to a printer that will print the first page efficiently, and to send the data stream for the second pages to a different printer that will print the second pages efficiently.
A still further aspect of the invention is to reformat the data stream for the second pages so that the data will be printed correctly on the different printer.
The above and other aspects of the invention are accomplished in an ultra-heavy mail piece processing system that first collects the data to be printed out and then formats the data for printing. A rendering process then determines how the mail piece will be printed. Based on the total number of pages in the mail piece, the system will direct mail pieces having total pages less than or equal to a lower bound to an automated print and mail process. Mail pieces having total pages greater than the lower bound but less than an upper bound are directed to a different print and mail process that requires some manual handling. Mail pieces that have total pages equal to or greater than the upper bound are directed to a third print and mail process.
In this third print and mail process, the data stream, which is the electronic image for each mail piece, is split into a data stream for the first page and a data stream for all the second pages for the mail piece. The initial data formatting is preserved for the data stream for each first page and the data stream for each first page is sent to a printer for printing in a one-up format. The data stream for each set of second pages is reformatted to allow the data stream for each set of second pages to be sent to and printed on a second printer in a two-up format. The second printer prints at a higher speed than the first printer, and utilizes a different post-printing cutting and stacking process. After each of the first pages and each set of second pages are printed, the first pages are manually collated with their corresponding set of second pages forming mail pieces, and each mail piece is then manually packaged up and the proper postage is applied for mailing.

Ultra-heavy mail piece processing system

Qwest Communications International, Inc.


A powered drywall sander and painter has a proximally located variable speed motor and a motor housing connected to a hollow lower handle. An upper handle telescopes into the interior of the lower handle. The motor rotates a drive shaft within the handles. The upper handle is fastened to an anti-rotation spring with an adjustable sleeve clamp. The upper end of the spring is clamped to a bottom slide to prevent rotational movement therebetween. A top slide having a sanding pad slidably engages the bottom slide. The rotation of the drive shaft is converted to lateral motion of the sanding pad at a distal end of the drive shaft. The sanding pad is free to swivel. The sanding attachment may be interchangeably replaced with a painting attachment. The painting attachment has a paint brush pad with bristles and a paint cup with a centrally located aperture which delivers paint to the paint cup. The painting attachment converts the rotational motion of the drive shaft into rotational motion of the paint brush pad. The painting attachment may be configured to swivel or may be fixed from swiveling motion with a bracket.

Conventional power drywall sanding or painting devices utilize motors which are typically located on distal ends of the devices. Use of these devices is tiring for the user because of the significant weight of the motor at the working end of the tool. This is particularly true of devices having extension handles. Moreover, two devices are required to perform sanding and painting operations. It is important that the working head be moveable, but that it be constrained against rotation. The device must also be capable of being locked in a predetermined position. It is desirable that a painter and/or sander be relatively light in weight because much of the work is done above the head of the user and excess weight results in fatigue to the user.


A dishwasher, in particular a household dishwasher, includes a control facility for performing a wash cycle to clean items to be washed based on a plurality of selectable wash programs. The control facility operates, in particular controls or regulates, a drain pump for pumping off wash fluid from the dishwasher. At least one of the wash programs includes an automatic execution of a pump-off sequence having at least three successively executed pump-off phases to define first, second and third pump-off phases, during each of which the drain pump is activated, with a break being provided between the first and second pump-off phases and a break being provided between the second and third pump-off phases, wherein the drain pump is deactivated during each of the breaks.

The present invention relates to a dishwasher, in particular a household dishwasher, having a control facility for performing a wash cycle to clean items to be washed based on a selectable wash program and having a drain pump that can be set, in particular be controlled or regulated, by the control facility for pumping off wash fluid from the dishwasher.
Commercially available dishwashers are configured to clean dishes with wash fluid automatically. However despite sometimes complex operating methods it is not always possible to avoid undesirable spotting on the cleaned dishes.

Dishwasher with an improved pump-off sequence


DNA sequences encoding antiviral proteins, amarandin 1 and 2 from Amaranthus viridis is disclosed. Expression vectors encoding amarandin 1 or 2 and transformed host cells are also disclosed.

The present invention relates to the entire nucleotide sequences of cDNAs that are encoding amarandin 1 and 2, ribosome-inactivating proteins having antiviral activity, of Amaranthus viridis.
According to ANTIVIRAL COMPOUNDS FROM PLANTS, 1st ed., CRC Press, Inc., (1990) and Bio/Technology (1992) 10:405-412, the ribosome-inactivating proteins (RIPs), classified as type 1 and 2, have antiviral and abortifacient activities with N-glycosidase activity which cleave the N-glycosidic bond of adenine in a specific ribosomal RNA sequence. Interest in ribosome-inactivating proteins stems from their potential utilization in agriculture and medicine, due to their antiviral activity and antifungal activity. Ribosome-inactivating proteins can be utilized either for the production of the multiple virus-resistant crops or for the inhibition of virus replication comprising virus-induced human diseases, like HIV-1 replication, selectively in cell cultures. Moreover, one can custom design extremely specific and very effective small peptide conferring an antiviral activity, from the basis of RIP structure, to interfere with the penetration stage of certain myxoviruses.
During our screening studies searching for new RIP we found that Amaranthus viridis crude extracts displayed both translational inhibitory and antiviral activities against plant viruses.

Antiviral proteins, amarandin 1 and 2, from Amaranthus viridis, DNAs encoding therefrom


A method for manufacturing a molding core includes: providing a cylindrical roller having a circumference surface coated with a first film layer; coating a second film layer on the first film layer; coating a preprocessed molding film on the second film layer; engraving a number of molding patterns on the preprocessed molding film to obtain a molding film; separating the molding film from the roller and spreading out the molding film to be a flat plate; and manufacturing the molding core using the molding film by electroforming method.

1. Technical Field
The present disclosure relates to a method for manufacturing a molding core.
2. Description of Related Art
Optical films include a number of micro structures, therefore, molding cores of optical films need to include a number of molding patterns mated with the micro structures. Currently, the molding patterns are formed by a laser knife. However, a lot of metal scraps are formed around the molding patterns when the molding core is machined by the laser knife and the metal scraps are difficult to be removed, and thus the quality of the molding core is influenced.
Therefore, it is desirable to provide a method for manufacturing a molding core that can overcome the above-mentioned limitations.


A pump having least one pump element with a pump piston guided in a sealed fashion in a cylinder bore (26) of a housing part delimiting a pump working chamber in the cylinder bore, and driven into a stroke motion. The working chamber is connected to an inlet conduit through by an inlet valve opening into the pump working chamber and to an outlet conduit through an outlet valve opening out from the working chamber. The inlet valve has a valve element acted on in a closing direction by a valve spring. The inlet conduit includes a first blind bore which adjoins the pump working chamber and has a smaller diameter than the cylinder bore a valve seat is formed at the transition from the cylinder bore to the first blind bore, and a second blind bore, as another part of the inlet conduit, feeds into the first blind bore.

1. Field of the Invention
The invention is directed to an improved pump for a fuel injection apparatus for an internal combustion engine.
2. Description of the Prior Art
A pump of the kind with which this invention is concerned, known from DE 198 48 035 A1, has at least one pump element with a pump piston that is guided in a sealed fashion in a cylinder bore of a housing part and delimits a pump working chamber in the cylinder bore with its end surface. The pump piston is driven into a stroke motion. The pump working chamber is connected to an inlet conduit via a connection controlled by an inlet valve opening into the pump working chamber and is connected to an outlet conduit via a connection controlled by an outlet valve opening out from the pump working chamber. The inlet valve has a valve element that cooperates with a valve seat and a valve spring acts on this valve element in the direction of the valve seat. The part of the inlet conduit feeding into the pump working chamber is comprised of a separate component that also contains the valve seat; this component is inserted into a bore of the housing part. The bore of the housing part is closed with a screw plug. The production and assembly of the known pump are complex and costly due to the large number of individual parts.

Pump, especially for a fuel injection device for an internal combustion engine


A vehicular lamp that decreases the amount of light blocked by the extension towards the inside of the vehicle and increases the diffused light radiated toward the outside of the vehicle. The vehicular lamp 100 has a projection lens 33, a light source 27, a reflector 29 having a reflecting surface 29a in which the light source 27 acts as an approximate focal point and light from this light source 27 is reflected toward the projection lens 33, a container-shaped body 21, and a cover 23 that along with the body 21 forms a light chamber. The cover 23 has a horizontal cross-section that is slanted with respect to an imaginary line 25 in the transverse direction of the vehicle, and the projection lens 33 has a rear side focal point f, the thickness of the lens 33 decreasing from the center portion toward the outer peripheral portions, and on the outer peripheral portions, a vehicular inside edge portion projects more toward the front side of the vehicle than the vehicular outside edge portion.

1. Field of the Invention
The present invention relates to a vehicular lamp provided with a projector-type lamp unit.
2. Background Art
In the projector-type headlamp 200 shown in FIG. 11, for example, a light source 204a of a light source bulb 204 is disposed in proximity to a first focal point of a reflector 203 having a rotational ellipsoidal surface, and a bilaterally symmetrical projection lens 202 having a rear side focal point is disposed in proximity to a second focal point at which light from this light source 204a converges. In this type of conventional projector-type headlamp 200, the light emitted from the light source bulb 204 converges once at the second focal point, and subsequently the light that diffused in a radial fashion is projected in the radiation direction by the projection lens 202.
When using the reflector 203 having a rotational ellipsoidal surface, light reflected at the reflector 203 is condensed in proximity to the rear side focal point of the projection lens 202, and the light that is refracted and emitted by the projection lens 202 is projected forward in a condensed state as a substantially parallel light flux. Such a reflector 203 is used, for example, in a high beam lamp unit, and can radiate light a long distance. However, in this type of reflector 203 having a rotational ellipsoidal surface, because the light cannot diffuse sufficiently in the horizontal direction, the sideways visibility is relatively reduced.
A technique for enhancing the sideways visibility, as shown in FIG. 12, is a projector-type headlamp 300 that uses a reflector 303 and a bilaterally symmetrical projection lens 302, where the reflector 303 is provided with a reflecting surface having a cross-sectional profile on the optical axis Ax that is generally ellipsoidal in shape, and an eccentricity thereof is set so as to increase gradually from a vertical cross-section to a horizontal cross-section, that is, a vertical cross-section has a generally ellipsoidal profile and the horizontal cross-section has a free-form surface profile based on an ellipse. See, e.g., Japanese Patent Application Publication No. JP-A-2001-76510.
In the projector-type headlamp 300, in particular in the horizontal cross-section, because the reflector 303 is designed such that the light rays from the light source 304a of the light source bulb 304 are reflected forward beyond the rear side focal point of the projection lens 302 so that their distance from the optical axis increases, the light diffuses in the horizontal direction, and it is possible to enhance the sideways visibility.
However, when using the reflector 303 having a reflecting surface whose vertical cross-section has a generally ellipsoidal profile and whose horizontal cross section has a free-form surface profile based on an ellipse in order to increase the diffusion in the horizontal direction, it is not always possible to accommodate the sharp slant of a cover 305 along an external contour of a vehicle body. As shown in FIG. 12, a portion of the diffused light emitted from the light source 304a and radiated toward the inside of the vehicle may be blocked by the extension 306 or the like.
In order to prevent the diffused light from being blocked in this manner by the extension, narrowing the diffusion angle of the light in the transverse direction of the vehicle may be considered, but in a bilaterally symmetrical optical system, because the left and right diffusion angles are identical, there is a problem in that the diffusion angle toward the outside of the vehicle is reduced when the diffusion angle toward the inside of the vehicle is reduced. In such a structure, there is a concern that the nighttime sideways visibility will decrease and bring about a deterioration in safety. In addition, in a conventional bilaterally symmetrical lens, the light incident on the outer peripheral portions of the lens toward the inside of the vehicle is reflected by the lens emitting surface, and as a result, the light utilization rate decreases, and the diffused light that is radiated toward the outside of the vehicle decreases.

Vehicular lamp and projection lens for decreasing an amount of blocked light


A wavelength tuning device of the invention tunes the reflected wavelength of a fiber Bragg grating, and includes: an optical fiber (102) in which a fiber Bragg grating (106) is formed; a base member (104) to which the optical fiber (102 is fixed; a first temperature sensor (112) that detects a temperature of the base member (104); a thermo-module (116) that adjust the temperature of the base member (104) such that the temperature detected by the first temperature sensor (112) is maintained at a desired temperature; a second temperature sensor (126) that detects an external temperature of the wavelength tuning device; and a temperature controller (130) that controls the thermo-module (116) such that the temperature of the base member (104) is maintained at the desired temperature based on the external temperature detected by the second temperature sensor (126).

1. Field of the Invention
The invention relates to a wavelength tuning device and a wavelength tuning method for tuning a reflected wavelength of a fiber Bragg grating. More particularly, the invention relates to a wavelength tuning device and a wavelength tuning method for automatically controlling variation of the reflected wavelength caused by temperature fluctuation.
2. Description of the Related Art
In recent years, there has been a rapid increase in demand for communication as a result of the increasing popularity of the internet etc., and high speed, large capacity networks using optical fiber are being installed. In high speed, large capacity optical networks of this type, Wavelength Division Multiplexing (hereinafter simply referred to as "WDM") transmission techniques are indispensable. In particular, great attention is being focused on Dense WDM (hereinafter simply referred to as "DWDM") techniques in which the wavelength interval is narrowed, and the optical carrier wave is densely arranged on the wavelength axis.
In addition, Optical Code Division Multiplexing (hereinafter simply referred to as "OCDM") transmission techniques are also gaining attention, and are expected to increase wavelength utilization through combined use with WDM or DWDM, and offer superior transmission security and demultiplexing. OCDM techniques perform demultiplexing by modulating using a different code for each channel on the transmission side, and decoding at the receiving side using the same code as the transmission side. Various techniques are known including techniques that combine time-spread/wavelength-hopping techniques (hereinafter simply referred to as "wavelength-hopping techniques") in which the assigned sequence on multiple wavelengths and the time domain of each wavelength is encoded, and phase coding techniques in which dispersed optical pulse trains are encoded.
Technology is known in which a fiber Bragg grating (hereinafter referred to simply as "FBG") is used as the optical filter device in WDM or DWDM systems, or the encoder/decoder in OCDM systems. The FBG is a device that includes a refractive index modulating region with a lattice shape, namely, a grating, formed in the core of an optical fiber. The FBG reflects a specific wavelength. However, it is known that the reflected wavelength of the FBG varies substantially in accordance with the external temperature (hereinafter also referred to as the "ambient temperature") surrounding the FBG as a result of temperature dependence of the refractive index of the FBG and expansion/contraction of the optical fiber caused by temperature, etc.
Methods for inhibiting variations of the reflected wavelength of an FBG caused by ambient temperature have been proposed such as that disclosed in Published Japanese Translation of PCT Application, JP-T-2000-503415. According to the method disclosed in JP-T-2000-503415, an optical fiber in which an FBG is formed is fixed on a ceramic board that has a negative coefficient of thermal expansion. Variations in the reflected wavelength of the FBG caused by fluctuations in the ambient temperature are corrected based on a change amount of the reflected wavelength of the FBG caused by expansion/contraction of the optical fiber, in accordance with expansion/contraction of the ceramic board.
However, particularly in the case when the FBG is used as the OCDM encoder/decoder described above, if there is any deviation in the reflected wavelengths of the FBGs between each paired encoder and decoder, transmission quality deteriorates. Accordingly, the reflected wavelengths must be made substantially the same. However, in the above method, wavelength variation can occur that can cause a wavelength difference between the encoder and decoder that exceeds the level of wavelength difference that is necessary to maintain transmission quality. Moreover, in the above method, the reflected wavelength is determined at the stage when the optical fiber is fixed and cannot be changed. Thus, if the optical light source wavelength varies, it is not possible to adjust the reflected wavelength of the FBG, and transmission quality deteriorates.

Wavelength tuning device and wavelength tuning method


A terminal and capacitor box is provided for mounting directly onto a generally cylindrical surface of an electric induction motor housing. The terminal box includes a generally rectangular body member adapted to receive a pair of capacitors therein. The body member includes a substantially planar deck surface, a first pair of substantially rectangular opposing sidewalls, and a second pair of opposing sidewalls. The second pair of sidewalls have a curved bottom edge preselectively contoured to conform to the curved surface of the electric motor housing. In addition to the above, the terminal box includes a torsional spring member for engaging the pair of capacitors and holding the pair of capacitors in place against the planar deck surface of the rectangular body member and between the sidewalls regardless of the orientation of the terminal box. Thus facilitating the manufacturing process by rendering the box less sensitive to rough handling and more ameanable to processing as a subassembly. A successive set of subassemblies are formed by attaching the capacitors and then the electrical connector to the box and then lastly pre-wiring certain connections within the box. Together, the assembled unit is available for later attachment to an electric motor.

1. Field of the Invention
The present invention pertains to the art of electrical junction boxes and more particularly to conduit boxes for use in allowing access to wiring for apparatus such as split capacitor induction motors. The box is adapted to hold in place a pair of capacitors and an industry standard electrical connector for manufacturing a motor conduit box sub-assembly having a substantial portion of the electrical connections completed before the box is mated to a motor.
2. Description of the Related Art
FIG. 1 illustrates one example of a prior art conventional split capacitor induction motor 1 including a pair of separately housed capacitors 2, 3, a motor lead wire bundle 4, and an electrical connector 5. This prior art motor configuration was difficult to manufacture due in part to the separately housed capacitors 2, 3 and the location of the lead wire bundle 4 on the motor housing. As would be appreciated by those skilled in the art, the electrical connections to the motor windings (not shown) necessitates at least three access holes in the motor housing, one at each capacitor and one for the lead wire bundle. Each of the access holes in turn requires a strain relief.
Further, each capacitor housing on the housing complicates the manufacturing process by requiring a gasket to prevent water or other moisture from entering the motor. Also, special care must be taken during the process of routing the lead wires from the windings to the capacitors and lead bundle.
The lead bundle is a problem during the manufacture of the motor in that it must be taped over or otherwise protected before the motor is painted. Also, the lead bundle must be handled carefully when the motor is placed into a carton for shipment in order to avoid damage thereto.
Lastly, the configuration shown in the FIGURE proves unweildly during field installation of the motor in that two hands are normally required to grasp and attach the electrical connector 5 of the motor to the electrical connector (not shown) at the customers site of installation.


The present invention relates to an L-arginine producing mutant strain, and a method for fabricating the same. In particular, the present invention relates to a polynucleotide comprising an argD2 gene (Ncgl2355) that is a putative gene of acetylornithine aminotransferase involved in arginine biosynthesis of Corynebacterium glutamicum, a polypeptide encoded by the polynucleotide, a recombinant vector comprising the polynucleotide, a transformant capable of producing L-arginine in a high yield, which is prepared by introducing the recombinant vector into an L-arginine producing host microorganism to overexpress the argD2 gene, and a method for producing L-arginine by culturing the transformant. The transformant of the present invention overexpresses the argD2 gene to produce L-arginine in a high yield, thereby being used in medicinal and pharmaceutical industries.

L-arginine is a free-form amino acid found in plant seeds or garlic. L-arginine has been widely used as an efficient additive in medicaments, food, or the like. L-arginine is useful as a drug for improving the hepatic function and brain function, and treating male sterility, and as an ingredient of multiple amino acid supplements. Also, L-arginine has been used as a food additive in fish cakes and health beverages, and has recently gained interest as a salt substitute for hypertension patients.
Conventional methods for L-arginine production by biological fermentation are based on the production of L-arginine directly from carbon and nitrogen sources. For example, L-arginine can be produced using a mutant strain derived from a glutamic acid-producing microorganism belonging to the genus Brevibacterium or Corynebacterium (Japanese Unexamined Patent Publication Nos. Sho57-163487, Sho60-83593 and Sho62-265988), or using an amino acid-producing microorganism, of which growth properties are improved through cell fusion (Japanese Unexamined Patent Publication No. Sho59-158185). Recently, it has been reported that L-arginine can be produced using a recombinant strain, of which an argR gene that participates in regulation of arginine biosynthesis is inactivated (US Patent Application No. 2002/0045223A1) and using a method for over-expressing an argF gene of arginine operon (Korean Patent Application No. 10-2004-107215).
In microorganisms, biosynthesis of L-arginine proceeds in eight enzymatic steps starting from the precursor L-glutamate and follows two different pathways, the linear pathway or the cyclic pathway.
In microorganisms belonging to the genus Corynebacterium, L-arginine is synthesized through the cyclic pathway from L-glutamate via N-acetylglutamate, N-acetylglutamyl phosphate, N-acetylglutamate semialdehyde, N-acetylornithine, ornithine, citrulline and argininosuccinate. These intermediates are synthesized through consecutive reactions catalyzed by enzymes such as glutamate N-acetyltransferase, N-acetylglutamate kinase, acetylglutamate semialdehyde dehydrogenase, acetylornithine aminotransferase, ornithine cabomoyltransferase, arginosuccinate synthase, and arginosuccinate lyase. These enzymes are encoded by argJ, argB, argC, argD, argF, argG and argH genes, respectively.
In order to produce L-arginine in a high yield, the present inventors have conducted studies on the enzymes involved in L-arginine biosynthesis for a long period time. They found that in the intermediate step of arginine biosynthesis, the enzymatic reaction involved in the conversion of N-acetylglutamate semialdehyde to N-acetylornithine is amplified to increase L-arginine flux, thereby improving the productivity of L-arginine.
A variety of aminotransferases are present in cells, and divided into four subgroups on the basis of their mutual structural relatedness. Subgroup I comprises aspartylornithine, alanine, tyrosine, histidiolphosphate, and phenylalanine aminotransferases, subgroup II comprises acetylornithine, ornithine, ω-amino acid, aminobutyrate, and phenylalanine aminotransferases, subgroup III comprises D-alanine and branched-chain amino acid aminotransferases, and subgroup IV comprises serine and phosphoserine aminotransferases (Perdeep K. MEHTA, et al, Eur. J. Biochem., 214, 549-561, 1993).
It has been known that in Corynebacterium glutamicum, an argCJBDF gene involved in arginine biosynthesis exists as an operon, and is regulated by feedback-inhibition due to arginine (Vehary Sakanyan, et al, Microbiology, 142:9-108, 1996). Thus, there is a limit in producing L-arginine in a high yield.

Corynebacterium glutamicum variety producing L-arginine and method for fabricating the same


Disclosed herein is a method for producing a 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. The method comprises forming a reaction mixture comprising at least one substituted or unsubstituted phenolphthalein compound, at least one substituted or unsubstituted primary hydrocarbyl amine, and an acid catalyst; and heating the reaction mixture to form 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine. An adduct of the 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine is formed either by using an excess of the primary hydrocarbyl amine in the first heating step, or by isolating crude 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine after the heating step and then reacting with a further amount of the primary hydrocarbyl amine. The 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine has a formula:

The present disclosure generally relates to methods for producing and purifying 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine monomers (hereinafter sometimes referred to as phenolphthalein derivatives), and polycarbonates as well as other polymers derived utilizing the monomers.
3,3-Bis-(4-hydroxy-phenyl)-3H-isobenzofuran-1-one (hereinafter referred to as phenolphthalein) has been used as an aromatic dihydroxy compound monomer for preparing polycarbonates, which are generally characterized with excellent ductility and high glass transition temperatures. Certain derivatives of phenolphthalein have also been used as aromatic dihydroxy compound monomers to prepare polycarbonate resins as well as polyarylate resins. For example, polycarbonate homopolymers have been prepared by an interfacial polycondensation method using phosgene and (phenolphthalein derivative) monomers such as 3,3-bis(4-hydroxyphenyl)phthalimidine and 2-phenyl-3,3-bis(4-hydroxyphenyl)phthalimidine (hereinafter sometimes referred to as "PPPBP").
Lin and Pearce (Journal of Polymer Science: Polymer Chemistry Edition, (1981) Vol. 19, pp. 2659–2670) reported the synthesis of PPPBP for preparing polycarbonates and other polymers by refluxing phenolphthalein and aniline hydrochloride in aniline for 6 hours, followed by recrystallization from ethanol. During this reaction, side products are created which, if not removed, can result in PPPBP having an unacceptable purity for use as a monomer or as a comonomer in subsequent polymerization reactions. Furthermore, the impurities in the PPPBP monomer include, for example, trace (parts per million) levels of phenolphthalein or phenolphthalein residues that can undesirably produce discoloration in the polycarbonates and other polymers derived therefrom, thereby affecting the transparency of the polymer product. Coloration is not a desirable attribute for many commercial applications. U.S. Pat. No. 5,344,910 discloses that copolymers of PPPBP were found to have poor melt stability resulting in foamy polymer melts and moldings, and discoloration of the resin during melt processing.
It would therefore be desirable to develop a process for improving the purity of phenolphthalein derivatives such as 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine, which can then be used for producing polycarbonates and other polymers having improved properties, such as lower visual coloration and a higher weight average molecular weight.

This patent is subject to a terminal disclaimer.

Methods for producing and purifying 2-hydrocarbyl-3,3-bis(4-hydroxyaryl)phthalimidine monomers and polycarbonates derived therefrom

Abstract: where R1 is selected from the group consisting of a hydrogen and a hydrocarbyl group, and R2 is selected from the group consisting of a hydrogen, a hydrocarbyl group, and a halogen.


A method and an apparatus for separating dry matter from liquid includes an enclosed separation environment capable of being pressure regulated. Within the enclosed separation environment, a suspension is brought into contact with at least one filter so as to accumulate dry matter on the at least one filter. The filter with the dry matter passes through at least one set of rollers such that liquid is removed from the dry matter on the at least one filter to form a substantially dry filter cake. Thereafter, the substantially dry filter cake is removed from the at least one filter. The above steps are performed in the enclosed separation environment either under vacuum or overpressure. The invention may be used in various fields such as the food industry.

Separation of dry matter from liquid is known in the art. Methods such as precipitation, centrifugation and filtering are commonly used for separation purposes in a vast number of industries. The latter separation method is relevant for the present invention.
Several problems concerning the separation of dry matter from liquid exist. In precipitation the particles in the liquid precipitate. Often a precipitation agent is added to the liquid. After precipitation the dry matter is situated on the bottom as sludge, wherein the sludge will still comprise a good deal of liquid, particularly in the area between the sludge and the liquid.
Centrifugation is a accelerated type of precipitation, where agents aiding the separation is also added. Centrifugation is a very expensive separation method.
When filtering liquids having a high dry matter content there are significant problems concerning accumulation of dry matter on the filter. This accumulation is known as the filter cake. In conventional methods the filter cake will grow until further filtering is impossible and the filter then has to be cleaned. There are various techniques for limiting the filter cake. One such technique is cross-flow. Here, the suspension (feed stream) is made to move along the filter in such a way that the filter cake is forced to move along by the stream.
Another filtering method is back flushing. Here, the movement of the suspension is reversed to lift the filter cake from the filter.
When using the cross-flow or back flushing methods the filter cake is not accumulated on the filter but is accumulated in the suspension. This requires the filtering process to be either stopped or for the existence of an outlet for the accumulated dry matter. In the latter situation the removed dry matter will still have a relatively high liquid content.
A further filtering method is flushing. The filtering process is stopped and the filter is washed. Here, the dry matter is accompanied by a lot of liquid.
In U.S. Pat. No. 4,310,424 suspended particles from waste suspensions are removed by the means of a rotating drum barrel under pressure. Bigger particles will be deposited on a polymer network and smaller particles will be retained in a hydrophobic foam.
In "Filtration and Separation", 1988 (improving cake de-watering) a system for the removal of water from sludge is described. The sludge is led pass a transport convey belt for partial dehydration. Hereafter, the sludge is led between 2 layers of synthetic filters, which in a continuing process is pressed through rollers. The first transport convey belt is not passed through the sludge suspension.
Nalco Chemical Company (1985) is disclosing a system for the dehydration of sludge from steel production by a twin-belt-filtering method. Sludge is pressed through two filter belts by the means of a pair of rollers. Two filter belts are used, wherein none is passed through the sludge suspension.
The above problems are overcome by the present invention by presenting a method and an apparatus capable of continuously removing dry matter from a liquid having a high dry matter content, and thereby provide a method and apparatus capable of reducing the loss of a liquid from the suspension and at the same time having an increased filtering capacity and a economical advantage over the prior art.


A pressfit terminal is to be inserted into a through hole defined in a substrate for electrically contacting with the through hole. The pressfit terminal includes a terminal main body and at least three protrusion portions. The at least three protrusion portions protrude outwardly from a surface of the terminal main body. At least part of the protrusion portions are arranged at intervals in a direction intersecting with an insertion direction of the terminal main body.

1. Filed of the Invention
The present invention relates to a pressfit terminal that can connect a connection terminal such as a connector to a printed wiring board without soldering and to a connection structure.
2. Description of the Related Art
In any of the conventional substrates such as a printed wiring board fitted with an electronic circuit loaded with electronic parts, connection terminals are used for electrical connection with any external source. There are many cases in which a plurality of connection terminals are assembled so as to form a connector. There are also many cases in which, not only electrical connection, but substantial mechanical strength is also required. For this reason, there are many instances in which connection terminals are used via insertion into through holes formed in a substrate instead of being loaded in the substrate surface.
In order to obtain stable electrical connection and mechanical strength, a connection terminal inserted into a through hole is often soldered. Mostly, the soldering process is practiced using eutectic crystal consisting of about 40% lead (Pb) and about 60% tin (Sn). However, as a result of recent tendencies to avoid the use of lead, specifically, due to the lead-free inclination, when connection terminals are soldered, it is required to use a lead-free brazing material. Nevertheless, generally, the lead-free brazing material requires temperature higher than that in a case of soldering with a eutectic crystal for connecting terminals. When the temperature is raised due to the soldering of the connection terminals, electronic parts forming an electronic circuit on a printed wiring board may incur an adverse influence. To solve this problem, attention has been focused on a pressfit terminal enabling highly reliable electrical connection without soldering (see JP-U-Hei.2-119514 and JP-B-2911043).
In a case where a substrate is thick due to multilayer structure, if only a single press contact portion between a pressfit terminal and an inner wall face portion of a through hole is provided in the thickness direction of the substrate, there is a fear that the substrate may bend due to the bending moment. To prevent this phenomenon, JP-U-Hei.2-119514 discloses a structure including plural press contact portions in the thickness direction of the substrate. JP-B-2911043 discloses a structure in which a body portion near a tip end of a pressfit terminal is divided into two parts and the two parts are deviated and can be contact with an inner wall face portion of a through hole.

Pressfit terminal and connection structure


An apparatus and a method for detecting a carrier signal of a phase shift keyed modulated signal. A first counter circuit generates a plurality of counts, with each count being a number of cycles of a reference frequency signal occurring between two consecutive rising edges of an intermediate frequency signal. A comparison circuit compares a first count of reference frequency cycles to a second count of reference frequency cycles when a difference between an initial count of reference frequency cycles and a first predetermined number is less than a second predetermined number. The first predetermined number represents a time period of one cycle of the nominal center frequency, and the first count and the second count respectively represent time periods of first and second cycles of a pair of consecutive cycles of the intermediate frequency signal. The comparison circuit generates a difference signal when a difference between the first count and the second count is less than a third predetermined number. A second counter circuit counts cycles of the intermediate frequency signal and generates a carrier detect signal when a count of the intermediate frequency signal cycles equals a fourth predetermined number.

Phase shift key (PSK) modulation of radio signals has been used in the past to transmit digital information between data processing systems. One example is shown in U.S. Pat. No. 5,150,070, entitled "Demodulator for biphase, suppressed-carrier PSK signals" by P. Rinaldi. The phase modulation technique uses a 180 degree phase shift to distinguish between a binary one and a binary zero. This forces the carrier to be zeroed-out during modulation. To demodulate the modulated signal, the prior art requires complex circuitry to reliably reconstitute the binary information at the receiver. The demodulators of the prior art must reconstruct the carrier. They require coherent demodulation to create a signal that is phase locked with the incoming signal, and they then must combine the two in a multiplier to detect the data. Consequently, the IF signal must be made synchronous with the demodulated signal off the carrier. Stated otherwise, the carrier and the local oscillator must be made synchronous to demodulate the PSK signal.
In phase shift key modulation, a carrier signal, for example a 2.4 GHz carrier signal, is selectively applied to a phase shift delay circuit, depending upon the binary state of control input to the delay circuit. For example, when there is a binary zero data state for the control input, no phase shift delay is applied to the carrier signal. Alternately, when there is a binary one data state, a phase shift delay is applied to the carrier signal. The carrier signal is then transmitted to the receiver. At the receiver, there is a local oscillator that oscillates at a slightly different frequency, for example 2.4 GHz plus 2 MHz. At the receiver, these two frequencies are mixed and a corresponding beat note signal, or intermediate frequency (IF) signal, is produced. Phase shift information, which has been imposed on the carrier signal, is then manifested in the IF signal at the receiver. A significant problem in such phase shift key modulation communication techniques is created by the drift in the frequency of the oscillator at the transmitter which generates the 2.4 GHz carrier signal, and the drift of the local oscillator at the receiver which generates the 2.4 GHz plus 2 MHz signal. The relative drift in the frequencies of these two oscillators results in unstable characteristics in the intermediate frequency produced at the receiver and, therefore, unreliable detection of the binary data being transmitted.
U.S. Pat. No. 5,561,689, filed Oct. 26, 1994, by Fleek et al., discloses a phase demodulation technique for wireless LAN that allows the carrier and the local oscillator to not be synchronous. A PSK modulated signal received at a receiving station is amplified by a limit amplifier to form a square wave signal having pulses of uniform height. To detect a carrier sense condition, the time between the rising edges of the square wave IF signal that occur in response to the modulation at the transmitter are detected using a counter during a carrier sense measurement window. Times between the like edges of the square wave signal that are shorter than normal for an unmodulated IF signal indicate a first binary value of the modulation. Longer than normal times between the like edges of the square wave IF signal indicate a second binary value.
To compensate for drift in the carrier and in the local oscillator frequencies, the nominal non-phase transition portions of the IF signal are periodically sampled and corresponding registers are updated. Nevertheless, for a reliable carrier sense indication the IF frequency of the receiving station is required to be constant for a large number of cycles. This requirement greatly constrains the difference in crystal references between the transmitting and receiving stations and makes the measurement window for detecting a carrier sense indication relatively large. Other factors associated with this particular approach that contribute to the requirement of a large measurement window are, for example, the phase noise of the voltage controlled oscillator (VCO) of the local oscillator (LO), and variations in the LO frequency that are caused by the phase locked loop (PLL) not being completely settled. By making carrier sense measurement window sufficiently large to allow for these factors, this particular technique occasionally provides false carrier sense indications, adversely affecting the reliability of the collision avoidance algorithm provided by the Media Access Control layer of the wireless LAN system. For example, after a crier sense condition is active, the measurement window is expanded to allow for the variations in the IF that are caused by the Phase Shift Modulation. As a result, a carrier sense indication occasionally remains active after transmission of a data frame is complete.
What is needed is a demodulation technique that permits the crystal references at both the transmitting and receiving stations of a wireless network to have a greater frequency tolerance, %hat prevents slow changes in the LO caused by PLL settling time to adversely affect carrier sense indications, and that reliably senses the end of a data frame and loss of the carrier.

Digital delta mode carrier sense for a wireless LAN

International Business Machines Corporation


A laser cutting head has a nozzle as well as a lens disposed in a holder that is moveable by a mechanical drive along the laser beam axis and has a working gas supply port at the nozzle side of the head. The head also has an annular groove that is defined by concentric internal and external cylinders and a drive gas supply port in the external cylinder at the laser supply side of the head. An annular piston is formed at the laser beam application side end of the movable lens holder, that is disposed in the annular groove. The piston may be pressed toward the nozzle side of the head by the pressure of drive gas supplied through the drive gas supply port. The drive gas pressure and the area of the piston is selected to define an offsetting pressure for reducing the effect of the cutting gas on the lens and lens holder.

1. Field of the Invention
The present invention relates to a laser processing head which laser cuts or welds a workpiece by condensing and applying a laser beam and injecting cutting gas to the workpiece, and a method of operation therefor.
2. Description of the Background Art
FIG. 5 is a sectional view of a conventional laser cutting head shown in Japanese Patent Unexamined Publication No. Sho. 63-273588. In this drawing, the numeral 1 indicates a laser beam, 2 denotes a cutting lens for condensing the laser beam optically, and 3 represents a moveable holder which holds the cutting lens 2. The holder 3 is inserted within the external cylinder 4 and is moveable in both directions coextensive with the in the axis of the laser beam 1. Teeth 3a are formed in a side face of the holder to engage with a worm gear 6. A motor 5 drives the moving holder 3 via a worm mechanism, consisting of the worm gear 6 and the teeth 3a. The motor 5 and worm mechanism constitute a drive section acting to drive the moving holder 3. A sealant 7, which serves as a seal for cutting gas 9, also serves as a guide for the moving holder 3. A nozzle 8, which includes a nozzle end 8a, applies a laser beam to a workpiece 10 after it is condensed by the cutting lens 2. Nozzle 8 also includes a cutting gas supply port 8b to receive the cutting gas 9 for injection onto the workpiece 10. 2a and 2b indicate positions of the cutting lens 2 in a movable range, and the corresponding focal points of the laser beam 1 are indicated by 11a and 11b. Typically, the volume defined by the cylinder 4 in the laser source direction is open to atmospheric pressure.
The operation of the laser cutting head will now be described in accordance with FIG. 5. The laser beam 1 is condensed optically by the cutting lens 2 and applied to the workpiece 10. The cutting gas 9, which is generally dry air in the case of aluminum cutting, is injected onto the workpiece 10 from the front end 8a of the nozzle 8 on the same axis as the condensed laser beam 1.
The cutting sequence of the laser cutting head will now be described. When the cutting lens 2 is located at position 2a, the corresponding focal point 11a is located at the surface of the workpiece 10, and the workpiece 10 is pierced at a cutting start point. When a hole is made, the motor 5 is driven under the control of a control signal from a numerical control apparatus, not shown, to move the moving holder 3 toward the workpiece 10 via the worm gear 6. The cutting lens 2 moves to position 2b and the corresponding focal point 11b is located at the bottom of the workpiece 10.
At this focal point 11b, laser cutting is performed with respect to the hole pierced. Since cutting gas pressure at this time must be large enough to blow the metal fused by laser energy toward the bottom surface of the workpiece 10, the internal gas pressure of the nozzle 8 is set to an extremely high pressure, e.g., in a range between 5 kgG/cm.sup.2 and 9 kgG/cm.sup.2.
Hence, high cutting gas pressure is applied to portions A of the lens and lens holder, marked with arrows (.uparw.) in the drawing. For example, if the cutting lens is 50 mm in diameter and the cutting gas pressure applied is 8 kgG/cm.sup.2, the thrust which presses the moving holder 3 toward the laser beam 1 application side (top side in the drawing) by means of the cutting gas pressure is approximately 300 kgf because the outside diameter of the moving holder 3 holding the cutting lens 2 is approximately 70 mm. Clearly, the motor 5, the worm gear 6 and other parts constituting the drive section for driving the moving holder 3 must be designed to resist a greater force or thrust.
In the conventional laser cutting head arranged as described above, the nozzle side end portions of the cutting lens and the moving holder that supports the cutting lens encounter a comparatively large force that results from the cutting gas that is supplied through the cutting gas supply port and flows within the nozzle for injection onto the workpiece from the nozzle tip. By contrast, the opposite end of the holder and lens is open to ambient air pressure. As a result, the drive means consisting of the motor, the worm gear and other parts for reciprocating the moving holder in the direction of the laser beam must be relatively large in size.

Laser processing head and method for operation thereof


A vehicle transfer robot (10) of the present invention, disposed vertically on the ground, is formed to have four vertical frames (110) disposed at a predetermined distance apart from each other and formed to have a quadrangular frame, and a quadrangle by connecting the upper end parts of the four vertical frames (110), respectively, wherein the vehicle transfer robot (10) includes: a frame part (100) including an upper frame (120); a driving part (200) installed at each of the lower end parts of the vertical frames (110) for moving the frame part (100); and a carriage (300) installed in the frame part (100) for loading a vehicle.

A conventional flat parking lot has parking lines formed by dividing an area on a flat floor through paint so as to form a parking unit.
Moreover, a plurality of the parking units are connected with one another adjoining one another to form parking modules, and a vehicle movement passage is formed between front surface parts of the parking modules.
That is, the conventional flat parking lot has a plurality of the parking units which are areas divided to park vehicles one by one, each of the parking modules has a plurality of the parking units adjoining one another, and the vehicle movement passage is formed between the parking modules.
In this instance, the vehicle movement passage deteriorates parking efficiency for the same area since occupying lots of valuable land resources.
Furthermore, in general, a mechanical parking lot has parking means that a vehicle is put on a parking palette, is lifted by a parking stand, and is put on a parking space together with the palette. Therefore, the conventional parking lot has several disadvantages in that it requires a lot of installation expenses of the parking palettes and in that it is difficult to utilize the rooftop of a building as a parking space since requiring parking palettes as many as the parking spaces.
Additionally, the conventional parking lot has fixed rails put in the parking space and the parking stand mounted on a horizontal transfer stand which is transferred in one direction along the fixed rails in order to execute parking and unparking of a vehicle in the parking space like the rooftop using the parking stand having the vehicle loading stand. Therefore, the conventional parking lot has another disadvantage in that it requires lots of changes in structure in order to install such a structure and in that it cannot actively park vehicles according to the form of the parking space.

Intelligent vehicle transfer robot for executing parking and unparking by loading vehicle


A current ratio device is used for forming a current transformer that can accurately scale down high currents to usable metering levels. The transformer has associated circuitry that renders it capable of functioning not only with ac and a mixture of ac and dc, but also when dc alone is present in the primary winding. The device employs a toroidal core and winding assembly that is cut along a plane containing the toroidal axis through a pair of diametrically opposite sections of the assembly that contain no windings, in order to separate the device into a pair of sub-assemblies that can be readily placed over a single turn primary, e.g. a busbar, without dismantling the same. Once so placed, the sub-assemblies can then be clamped together again to reform the device and the winding portions externally connected to the circuitry, the latter being such as to avoid the accuracy of measurement being significantly effected by the unavoidable increase in core reluctance that will have resulted from the separation of the core assembly into two sub-assemblies.

Petar N. Miljanic et al in an article "An Electronically Enhanced Magnetic Core for Current Transformers" published in IEEE Transactions on Instrumentation and Measurement, Vol 40, No. 2, pp 410-414, April, 1991 (see also U.S. Pat. No. 4,841,236 issued Jun. 20, 1989) have described a technique that increases the apparent permeability of the magnetic core of a current transformer by electronically providing the magnetizing current for the core, whereby the ratio between the primary and secondary currents is rendered virtually without error.
There are two basic limitations in the various devices that have been disclosed by Miljanic et al for carrying this technique into practice.
First, while the above disclosure provided for current transformers that can operate with pure ac, or with a mixture of ac and dc, operation with dc alone was not possible.
Second, the devices were not structurally adapted for easy use with busbars. For on-site measurement of high currents in a busbar that is part of an already installed system, it is inconvenient to have to dismantle the busbar in order to thread a toroidal core onto it from one end, as is necessary if the busbar is to form a single turn primary to generate currents in a secondary winding formed on the core. This problem has been addressed in the past in some hand-held metering devices by making the transformer core in two parts that are pivoted together and can be opened to be placed over the busbar from a side thereof and then closed when in place to surround the busbar. The problem with "openable" cores of this type, however, has been the loss of accuracy that results from the increased reluctance in the core that arises from the unavoidable air gap where the two parts of the core come together. No matter how smoothly polished the mating end faces of such a core are made, the result is always a significant increase in reluctance relative to that of an uninterrupted toroidal core.

Current ratio device and toroidal core assembly therefor


An apparatus and method for compressing gas refrigerant using two different compressors operated alternatively in a series or parallel mode for obtaining two different compression ratios and thereby provide efficient operation for both a relatively lower suction pressure and a relatively higher suction pressure. This system avoids an unbalanced mass flow rate when the compressors are operated in series by unloading a downstream one of the compressors. When operated in the series mode, refrigerant is bypassed back to a suction inlet of the downstream compressor during a portion of a compression stroke of the downstream compressor for equalizing the mass flow rate through the two compressors.

1. Field of the Invention
This invention relates generally to compressors and more particularly to a compressor that can be easily adapted for use in any one of multiple systems so that identical compressor modules can be manufactured but can be installed in different applications having different operating conditions. The compressor can also be used in an application which has multiple operating conditions, such as a refrigeration system having multiple compartments maintained at multiple different temperatures, and can automatically change its operating mode in response to changes in operating conditions.
2. Description of the Related Art
Refrigeration and air conditioning systems have long used the phase change refrigeration cycle for cooling objects, such as food, to reduced temperatures and for maintaining them at a reduced temperature for preservation. These refrigeration systems have a closed loop in which a refrigerant is compressed to a compressor discharge pressure and discharged into a heat exchanging condenser where heat is rejected. Refrigerant is accumulated in the condenser and metered from the condenser into an evaporator where heat is accepted through the evaporator walls from the stored objects in thermal connection with the evaporator. The rate at which the refrigerant is metered into the evaporator is controlled by a temperature control system which senses the temperature of the objects and meters the refrigerant into the evaporator as a function of evaporator temperature. From the evaporator the refrigerant is returned at a suction pressure to a compressor to complete the closed loop.
The design temperature that is sought to be maintained by a refrigeration system is dependent upon the particular application. Because there are an extensive variety of applications for refrigeration systems, their design temperatures vary over a wide range. For example, a refrigerator may be designed to preserve food in a state that does not damage some foods or require thawing of the foods. This refrigerator has a fresh food compartment in which food is retained in a relatively higher temperature zone at slightly above 0° C. Another refrigeration system may be designed to freeze food and therefore has a freezer compartment in which food is retained in a significantly lower temperature zone, for example in the range of −17° C. to −40° C. In the higher temperature zone of the fresh food compartment, the refrigerant is exposed to a higher temperature than in the lower temperature freezer zone. Consequently, the refrigerant in the evaporator of the fresh food compartment has a higher temperature, pressure and density and therefore presents a higher suction pressure to the compressor. The refrigerant in the evaporator of the freezer compartment is exposed to a lower temperature and therefore has a lower temperature, pressure and density and therefore presents the compressor with a lower suction pressure.
Alternatively, a single refrigeration system can be provided with multiple cooling compartments for maintaining objects at a different temperature in each compartment. A refrigerator may have both a fresh food compartment and a freezer compartment in which food is retained at the above temperatures. In the higher temperature zone of the fresh food compartment, the refrigerant is exposed to a higher temperature than in the lower temperature freezer zone. Consequently, the refrigerant in the evaporator of the fresh food compartment has a higher temperature, pressure and density and therefore presents a higher suction pressure to the compressor. The refrigerant in the evaporator of the freezer compartment is exposed to a lower temperature and therefore has a lower temperature, pressure and density and therefore presents the compressor with a lower suction pressure. Although it is common to provide home refrigerators with only a single evaporator and it is also known to connect two evaporators in series, a compressor can supply refrigerant to multiple evaporators for multiple compartments, with each compartment having its own temperature control system and expansion valve for metering refrigerant flow through the expansion valve for its compartment.
Although compressors are used in refrigeration systems, they are also used in a variety of other applications. Compressor applications expose compressors to different suction pressures and other intake gas parameters, either because compressors of one design may be installed in different applications each having a different operating condition or because a single compressor may be exposed to multiple operating conditions in a single application. The existence of these different operating conditions means that the compressor may alternatively be exposed to: (1) a relatively higher gas temperature, density and suction pressure and (2) a relatively lower gas temperature, density and suction pressure. For a compressor that has a piston reciprocating in a cylinder, the volume flow rate is proportional to the piston stroke and is simply the displacement. However, the mass flow rate is not only a function of the displacement, but also is a function of the gas density. This is the result of the fact that the same volume of a gas has less mass if the gas is at a lower density and more mass if at a higher density. Therefore, when a refrigeration compressor is presented with different operating conditions that provide a gas at different densities and suction pressures, the mass flow rate through the compressor changes in response to changes in density, temperature and suction pressure of the gas refrigerant.
If a compressor is optimized for any one of these multiple operating conditions, it will not be optimized for the other. If it is optimized for an intermediate condition, it will not be optimized for any. For example, if the compressor is designed to operate at a relatively lower suction pressure and density and to provide a selected mass flow rate under that operating condition, if it is operated at a relatively higher suction pressure and density condition, the mass flow rate through the compressor will increase approximately in proportion to the change in the density.
Under the condition of a higher temperature, density and suction pressure, such as for supplying refrigerant to cool a fresh food compartment, the compressor should have a lower compression ratio in order to deliver compressed refrigerant gas at the desired discharge pressure into the condenser. At the condition of a lower temperature, density and suction pressure, such as for supplying refrigerant for cooling a freezer compartment, a higher compression ratio is needed to deliver the gas to the condenser at the desired discharge pressure.
It is an object and feature of the invention to provide a compressor that can adapt to these different operating conditions by changing its mode of operation in order to optimize its efficiency and provide the desired compression ratio for both operating conditions.

Dual mode compressor with automatic compression ratio adjustment for adapting to multiple operating conditions