A capacitor array includes a plurality of comb capacitors sharing a common comb electrode. At least one of the comb capacitors has a comb electrode as a single base part. Each of the other ones of the comb capacitors has an electrode formed by coupling a plurality of base parts. In the other ones of the comb capacitors, a space between a wire coupling the base parts and an end of each of comb teeth of the common electrode, which is interposed between the base parts, is larger than a space between a base of each of the base parts of the plurality of comb capacitors and an end of each of the comb teeth of the common electrode, which is interposed between comb teeth of the base part.

The present disclosure relates to capacitor arrays, and layout of a plurality of comb capacitors forming a capacitor array.
Numbers of elements are arranged in a semiconductor integrated circuit, it is thus important how best to utilize limited space on a substrate. In particular, it is important how efficiently to arrange capacitive elements requiring a larger area than other elements. Thus, area-efficient comb capacitors are often used in a semiconductor integrated circuit (see, for example, U.S. Pat. No. 7,022,581).
The capacitance of a comb capacitor depends on the number of comb teeth. Various numbers of comb teeth are employed, thereby forming a capacitor array including a plurality of comb capacitors.
For example, a capacitor array shown in FIG. 7 includes three comb capacitors 100, 110, and 120. The comb capacitors 120, 110, and 100 have 1, 2, and 8 comb tooth/teeth, respectively. The comb teeth of the comb capacitors 100 and 110 are symmetrically arranged relative to the comb tooth of the comb capacitor 120, thereby averaging the tilt of the surfaces of layers of a semiconductor integrated circuit to increase the matching ratio of the comb capacitors (see, for example, U.S. Patent Publication No. 2006/0270145).

Capacitor array and signal processor including the array

Panasonic Intellectual Property Management Co., Ltd.


An NFC device includes first and second secure elements, an NFC router, and a processor. A method involves emulating, by the NFC router in response to a command from the processing device, an RF card emulation transaction. The RF card emulation transaction includes transmitting by the NFC router a command to the first and second secure elements to verify the presence of NFC transaction applications in the first and second secure elements. The method also includes receiving, by the NFC router, responses from the first and second secure elements and a new RF message from an NFC terminal. The responses indicate the NFC transaction applications stored by the first and second secure elements, and the new RF message relates to an NFC transaction. The new RF message is routed to the first or second secure element based on the responses.

Technical Field
The present disclosure relates to the field of near field communication (NFC) communications, and in particular to an NFC device with multiple secure elements and to a method of routing messages in such a device.
Description of the Related Art
Mobile telephones and other types of mobile devices are increasingly being equipped with near field communication (NFC) interfaces, which enable them to perform electromagnetic transponder functions in addition to their other functions. In particular, such devices are able to emulate the functions of an electromagnetic transponder, which could be of the contactless card type, or the contactless reader type. Such functionality for example enhances the mobile device, by allowing it to be used for various applications, for example as an electronic wallet allowing payments to be made for accessing services such as transport networks.
To emulate the operation of a contactless card, the mobile device is generally equipped with a contactless front-end integrated circuit (CLF), also called an NFC router. This router is equipped with a radio frequency (RF) transceiver front-end coupled to a low-range antenna to match the communication capabilities of an electromagnetic transponder. In some applications, one or more secure elements (SE) or embedded secure elements (eSE), either integrated in the mobile device or contained in a micro-circuit of the USIM (universal subscriber identification module) or μSD (micro secure digital), can be used to provide authentication and other functions.
The NFC router comprises an NFC routing table, which indicates to which hardware the NFC messages received by the NFC router should be routed. For example, some NFC messages, such as those relating to certain types of electronic payment, are to be routed to a secure element of the mobile device. For instance, a VISA application may be running in communication with a Secure Element of a USIM (the name "VISA" may correspond to registered trademarks).
In some cases, the mobile device comprises more than one secure element, and there may be one or more applications stored by each secure element that is capable of handling a given transaction. In such a case, it is desirable that the mobile device is capable of selecting the application to be used among the available applications on all secure elements.
However, a difficulty is that the NFC router is not aware of the list of applications stored by each secure element. Furthermore, when an RF message is received and needs to be routed to a secure element, it is not permitted and nor is there time to interrogate all of the secure elements in order to obtain the lists of applications available on each secure element. There is thus a need in the art for a solution that addresses some or all of these difficulties.


Various arrangements for imaging a traffic light are presented. A distance to the traffic light from a vehicle may be determined. A camera mode may be selected based on the determined distance to the traffic light. One or more images from one or more cameras may be captured and received based on the selected camera mode. A state of the traffic light within the one or more received images may then be determined. The vehicle may then be driven autonomously based on the determined state of the traffic light.

For autonomous driving systems and driver-assistance systems to safely pilot vehicles, the systems may need to be able to determine the current state of road conditions with a high degree of accuracy, including conditions that were initially intended for use by a human. For example, throughout the world, traffic lights are used to determine whether a vehicle is permitted to proceed into an intersection or is required to stop before entering the intersection. An autonomous driving system or driver-assistance system controlling the vehicle may need to successfully identify such traffic lights and determine the state of a traffic light in order to safely control the vehicle in the vicinity of the intersection. While recognizing a traffic light and determining the state of a traffic light with a high degree of accuracy is needed, power consumption by an autonomous driving system is also a concern, especially when such a system is installed on an electric vehicle.

Traffic light detection using multiple cameras

CHONGQING JINKANG NEW ENERGY AUTOMOBILE CO., LTD.


A coupling for forming an optical plug connection between two optical plug connectors, the coupling having a guide sleeve and a sleeve-receiving cage with an interior space for receiving the guide sleeve. The sleeve-receiving cage has plug-in openings arranged opposite one another on a longitudinal axis of the sleeve-receiving cage and which serve for the plugging-in of in each case one ferrule of the respective optical plug connector into the guide sleeve in, in each case, one direction parallel to the longitudinal axis. The plug-in openings each are at least regionally surrounded by longitudinal stops of the sleeve-receiving cage for preventing the guide sleeve from being pulled out of the interior space of the sleeve-receiving cage, and the sleeve-receiving cage having two sleeve-receiving cage parts, and detent connection parts of the sleeve-receiving cage parts are engagable into one another with detent action via the sleeve-receiving cage parts being slid onto one another in a direction parallel to the longitudinal axis.

The present invention relates to a coupling for forming an optical plug connection between two optical plug connectors, the coupling having a guide sleeve and a sleeve-receiving cage with an interior space for receiving the guide sleeve, the sleeve-receiving cage having plug-in openings which are arranged opposite one another on a longitudinal axis of the sleeve-receiving cage and which serve for the plugging-in of in each case one ferrule of the respective optical plug connector into the guide sleeve in, in each case, one direction parallel to the longitudinal axis, the plug-in openings each being at least regionally surrounded by longitudinal stops of the sleeve-receiving cage for preventing the guide sleeve from being pulled out of the interior space of the sleeve-receiving cage, and the sleeve-receiving cage having two sleeve-receiving cage parts, and the sleeve-receiving cage parts having in each case one detent connection part for forming a detent connection.
In the case of customary commercially available optical plug connectors, provision is generally made for the ferrule to surround at least one light conductor. At the front end of the ferrule, the light conductor is exposed. In order to be able to connect two optical plug connectors to one another such that light signals can be transmitted from the light conductor of one ferrule to the light conductor of the other ferrule, the ferrules and the light conductors arranged therein must be arranged in a very exact manner relative to one another. In general, for this purpose, the ferrules of the two optical plug connectors that are to be connected to one another are connected to one another by means of a corresponding coupling such that the front ends of the ferrules and the light conductors arranged therein bear directly against one another and are correspondingly aligned. To ensure this, in the prior art, couplings for forming an optical plug connection between two optical plug connectors are known which have a sleeve-receiving cage, in the interior space of which there is arranged a guide sleeve. By insertion of the ferrules into the mutually oppositely situated insertion openings of the guide sleeve, the ferrules and thus also the light conductors arranged therein are arranged exactly relative to one another such that the light transmission from one optical plug connector to the other functions. The ferrules of the optical plug connectors are generally mounted in corresponding housings of the optical plug connectors so as to be movable, preferably movable in spring-loaded fashion, such that the guide sleeve can ensure a corresponding alignment of the ferrules relative to one another. In general, the ferrules are held with clamping action in the guide sleeve. Here, in the prior art, it may occur that, when the optical plug connectors are pulled out of the coupling and thus when the ferrules are pulled out of the guide sleeve, the guide sleeve is inadvertently also pulled out of the sleeve-receiving cage. To prevent this, the sleeve-receiving cage has longitudinal stops, normally designed as undercuts, which are intended to retain the ferrules in the interior space of the sleeve-receiving cage. In the case of the coupling and the sleeve-receiving cage being produced in a casting and/or injection-molding process, the production of these longitudinal stops designed as undercuts is generally associated with increased tooling outlay. In order to be able to be demolded, the longitudinal stops or undercuts are often of relatively shallow form, such that, in practice, it is sometimes the case that the guide sleeve is inadvertently pulled together with a ferrule out of the sleeve-receiving cage during the release of the optical plug connection.
In the prior art, couplings of the abovementioned type are also already known in which the sleeve-receiving cage is comprised of two sleeve-receiving cage parts which can be connected to one another by means of a detent connection. In this context, reference is made to WO 2011/128375 A1. In said document, provision is made for the sleeve-receiving cage to be composed of a main part and of a cover which can be slid laterally onto said main part, wherein the cover can be fastened to the main part by means of a detent connection. In the case of the coupling presented in WO 2011/128375 A1, when the cover has been released, the guide sleeve can be inserted into the main part of the sleeve-receiving cage, as can be seen particularly clearly in FIG. 2 of WO 2011/128375 A1.
The possibility of laterally inserting the guide sleeve into the interior space of the sleeve-receiving cage makes it possible for the longitudinal stops to be formed such that the guide sleeve can no longer be inadvertently pulled together with a ferrule out of the sleeve-receiving cage.
This solution, as is realized in WO 2011/128375 A1, can be realized only in the case of couplings in which the sleeve-receiving cage is laterally accessible.

Coupling for forming an optical plug connection


A plurality of rolling elements is in rolling contact with a metal outer race and is retained within a bearing cage. An annular bushing partially encloses the outer race, the annular bushing being split along a radial plane into two bushing halves molded of an engineered thermoplastic elastomer. The bushing halves are retained axially together such that axial movement of the outer race is limited. The annular bushing may incorporate integral annular seals and may have a rounded radially outward surface to facilitate self-alignment of the bearing assembly.

This invention relates generally to bearing assemblies having a flexible annular bushing and, more particularly, to a bearing assembly suitable for the mounting of steering columns and similar applications.
In such applications, a bearing assembly is required that isolates a shaft, for example a steering column, with respect to noise and vibration. In addition, a "zero clearance" bearing may be desired in those applications to further improve noise and vibration characteristics and maintain a "tight" feel. A needle bearing, for example, may have a split outer race and split bearing cage forced against the shaft by a rubber bushing. The rubber bushing requires an undercut to receive the needle bearing and lip seals that are difficult to manufacture and limit design options.
The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.


Techniques and examples of overhead reduction for linear combination codebook and feedback mechanism in mobile communications are described. A user equipment (UE) receives from a base station of a network one or more reference signals via a communication link between the UE and the base station. The UE constructs a channel state information (CSI) feedback by utilizing a correlation of channel responses in a frequency domain to reduce feedback overhead. The UE then transmits the CSI feedback to the base station.

Unless otherwise indicated herein, approaches described in this section are not prior art to the claims listed below and are not admitted as prior art by inclusion in this section.
In 5th Generation (5G) New Radio (NR) networks, two types of channel state information (CSI) feedback schemes, Type I and Type II, have been defined. In Type I of CSI feedback, the conventional dual codebook structure is enforced. Type II of CSI feedback targets high-resolution CSI acquisition for multi-user multiple-input-and-multiple-output (MU-MIMO) operations. A linear combination codebook is assumed for Type II CSI feedback. There are three categories under Type II, namely Category I, Category II and Category III. With Category I, a linear combination (LC) codebook is assumed.
With Category II of Type II of CSI feedback, channel covariance matrix R measured at a user equipment (UE) is fed back from that UE to the network to facilitate MU-MIMO transmission. For effective MU-MIMO transmission with small cross-talk, typically subband feedback is necessary. Hence, subband feedback with the covariance matrix may be necessary.

Overhead reduction for linear combination codebook and feedback mechanism in mobile communications


An oil system of a turbine engine and a method for driving an oil pump of such oil system are disclosed. In various embodiments, the oil system comprises an oil pump for fluid communication with one or more lubrication loads of the turbine engine, a first source of motive power and a coupling device. The first source of motive power is drivingly engaged to the oil pump for driving the oil pump during a first mode of operation. The coupling device is configured to drivingly disengage a second source of motive power from the oil pump during the first mode of operation and drivingly engage the second source of motive power with the oil pump to drive the oil pump during a second mode of operation.

Conventional practice on a multi-spool gas turbine engine is to have the engine oil pump driven via the high-pressure spool of the engine. During start-up, the high-pressure spool usually turns before the low-pressure spool which drives the load so this ensures that sufficient oil pressure is available to bearings associated with the rotation of the low-pressure spool as soon as possible during the operation of the gas turbine engine to achieve good bearing life and reliability. However, in some situations or for engine types where the low-pressure spool of the multi-spool gas turbine engine would be driven before or without necessarily having to drive the high-pressure spool, arrangements where the engine oil pump is driven via the high-pressure spool may not be optimal.

Oil system for turbine engine and related method


Process for the oxidation of aldehydes to the corresponding acids in which an aldehyde as substrate is oxidized to the corresponding acid in the presence of an equimolar amount, or a molar excess, of periodate, catalytic amounts of dichromate or CrO3, and in the presence of an acid in water, a water/solvent mixture or in a solvent at a temperature of xe2x88x9220xc2x0 C. to +50xc2x0 C.

The invention relates to a process for the oxidation of aldehydes to the corresponding carboxylic acids.
Oxidation is a fundamental transformation in organic synthesis, so that numerous methods have already been described for it in the literature. Despite this, direct conversion of aldehydes to the corresponding carboxylic acids, in particular in the presence of labile substituents, for example an unsubstituted or substituted benzyl group, is still associated with problems. Conventional methods, which use permanganate (Org. Syn., Coll. Vol. 2, 538 (1943)) or chromium-based reagents (J. Org. Chem., 2868 (1967)), only lead to moderate yields of the desired carboxylic acid. More recent methods which are based, for example, on the use of hypochlorite (Tetrahedron Lett., 23, 3131 (1982)) or RuCl3/NaIO4 (J. Org. Chem., 46, 3936 (1981)) are similarly without success. These variants, in addition to the low yields, also have the disadvantage that extreme overoxidation with breakage of the Cxe2x80x94C bond readily occurs, so that novel oxidation methods are still being sought.
It is an object of the invention to find a suitable method for the oxidation of aldehydes to the corresponding carboxylic acids in which, in particular, even the reaction of highly enolizable aldehydes in the presence of labile substituents is ensured to a great extent.
Unexpectedly, this object was achieved by using periodate in combination with dichromate or CrO3 in the presence of an acid.
The invention therefore relates to a process for the oxidation of aldehydes to the corresponding acids, which comprises oxidizing an aldehyde as substrate to the corresponding acid in the presence of an equimolar amount, or a molar excess, of periodate, catalytic amounts of dichromate or CrO3, and in the presence of an acid in water, a water/solvent mixture or in a solvent at a temperature of from xe2x88x9220xc2x0 C. to +50xc2x0 C.
In the inventive process, aldehydes are oxidized to the corresponding acids.
Suitable aldehydes are compounds of the formula I
where R is an unbranched, branched or cyclic, unsubstituted or substituted C1-C20 alkyl radical, an aryl or heteroaryl radical or a heterocycle.
Alkyl radicals are taken to mean unbranched, branched or cyclic alkyl groups. These radicals can be unsubstituted or substituted by one or more substituents which are inert under the reaction conditions, such as acyl, carboxyl, halogen, C1-C8-alkoxy, C3-C8-cycloalkyl, unsubstituted or substituted aryl radical, such as phenyl or naphthyl, heteroaryl, heterocycle etc., each of which may be substituted by phenyl, C1-C12-alkyl, C1-C8-alkoxy, halogen, aryloxy.
Aryl is taken to mean phenyl or naphthyl which in turn can be unsubstituted or substituted by acyl, carboxyl, halogen, C1-C8-alkoxy, C3-C8-cycloalkyl, etc.
Heteroaryl radicals are 5- or 6-membered aromatic rings which have 1 to 3 heteroatoms selected from the group consisting of O, N or S. These radicals can also be unsubstituted or substituted by acyl, carboxyl, halogen, C1-C8-alkoxy, C3-C8-cycloalkyl, etc. In addition, the heteroaryl radicals can be present as benzocondensed ring systems which can also be substituted as described above.
Heterocyclic radicals are 5- or 6-membered nonaromatic rings which have 1 to 3 heteroatoms selected from the group consisting of O, N or S. These radicals can in turn be unsubstituted or substituted by acyl, carboxyl, halogen, C1-C8-alkoxy, C3-C8-cycloalkyl, etc. In addition, the heterocyclic radicals can also be present as benzocondensed ring systems which can also be substituted as described above.
Preferred aldehydes are aldehydes of the formula I where R is an unbranched or branched, unsubstituted or substituted C1-C20 alkyl radial. Preferred substituents are halogen, C1-C8-alkoxy, aryloxy or phenyl which is unsubstituted or substituted by C1-C12-alkyl, halogen, C1-C8-alkoxy, aryloxy.
Particular preference is given to aldehydes of the formula I where R is an unbranched or branched C1-C2-alkyl radical which is substituted by a phenyl which is monosubstituted or disubstituted by C1-C4-alkyl, C1-C4-alkoxy, phenoxy, fluorine or chlorine.
The inventive oxidation of aldehydes is performed in the presence of an equimolar amount, or of a molar excess, of periodate. Preferably, 1.1 to 10 molar equivalents, particularly preferably 1.2 to 5 molar equivalents, of periodate are used. Periodate is used here as Na, K or Bu4N salt, sodium periodate being preferred.
In addition, for the inventive oxidation, dichromate or CrO3 is used in catalytic amounts. Suitable dichromates are Na dichromate or K dichromate. Preferably sodium dichromate is used. The amount of dichromate or CrO3 is from about 0.1 to 20 mol %, based on the substrate. Preferably, an amount of from 0.3 to 3 mol % dichromate or CrO3 is added.
As third component an acid is added. Suitable acids here are sulfuric acid, HCl, HNO3, p-toluenesulfonic acid (p-TSA), HBF4, H5IO6, CF3SO3H or perfluorotetradecanoic acid (PFTDA) or mixtures thereof. Preferred acids are H2SO4, HNO3 and H5IO6, and mixtures thereof.
The acid is used in an amount corresponding to 1-30 mol % H+, preferably 5-20 mol % H+, based on the substrate.
The inventive oxidation is performed in water, in a solvent or in a water/solvent mixture.
Suitable solvents are toluene, chloroform, dichloromethane, ethyl acetate, diethyl ether, methyl t-butyl ether, dimethoxyethane, 2-methoxyethyl ether, triethylene glycol dimethyl ether, dioxane, THF, acetone, isopropyl acetate and acetonitrile.
In the oxidation of the aldehydes, preferably, the three oxidation components periodate, dichromate or CrO3, and acid are dissolved in water. The substrate to be oxidized is then added with stirring. The substrate can be added as such or if appropriate as solution in one of the above described solvents or water/solvent mixture.
The reaction temperature, depending on the solvent system chosen, is from xe2x88x9220xc2x0 C. to +50xc2x0 C., preferably from xe2x88x9210xc2x0 C. to +30xc2x0 C., and particularly preferably from 0xc2x0 C. to 25xc2x0 C.
If a two-phase system is employed, the reaction mixture is stirred vigorously during the entire reaction. If only an aqueous phase is employed, the intensive stirring may not be necessary.
The reaction time depends on the substrate used and is between 1 and 40 hours. Preferably, the reaction time is between 6 and 30 hours, particularly preferably between 12 and 25 hours.
If appropriate, a further portion of periodate and/or acid can be added to the reaction mixture after a part of the reaction time, in order to complete the oxidation to the carboxylic acid.
At the end of the oxidation the corresponding carboxylic acid is isolated from the reaction mixture. Depending on the physical state, this is performed by conventional methods, for example by extraction, filtration etc.
The remaining reaction solution can be worked up to regenerate the periodate. This can be performed by methods known from the literature, for example by chemical or electrochemical oxidation. Preferably the periodate is regenerated by ozone, as described for example, in WO 98/27118. The regenerated periodate can then be reused for further oxidations.
By means of the inventive process, aldehydes are up to 70% or more converted to the corresponding carboxylic acids, depending on the reaction time. Unreacted aldehydes may be readily removed from the end product when it is isolated.
A further advantage of the process is the simple reaction procedure, where it is an advantage, in particular, that even in the case of aldehydes having labile constituents, for instance an unsubstituted or substituted benzyl group, high yields and high purities are obtained, compared with the prior art.

Process for preparing carboxylic acids by oxidation of aldehydes

DSM Fine Chemicals Austria NFG GmbH and Co KG


To cover peak loads an auxiliary circuit having a water store which can be charged from the main circuit is connected to the main circuit of a thermal power station. The stored energy carrier is expanded by throttling, whereupon the vaporous part performs work in a peak-load turbine or in part of the main turbine, which is designed for this purpose, while the unvaporized part is returned to the main circuit in such a way that the low-pressure bleed points of the main turbine are relieved and the output of the main turbine is thus increased. The water store is preferably fed with condensate from the reheater.

The present invention relates generally to a process for evening out load fluctuation in an electricity supply network. The invention also relates to equipment for carrying out the process.
Thermal energy storage in thermal powr plants is an excellent means for dealing with medium-term fluctuations in the energy demand of the consuming network.
Processes for evening out load fluctuations and equipment required for carrying out the processes are known (Article by Gilly and Beckmann, Spitzenlastdeckung durch thermische Energiespeicherung [Covering Peak Loads by Thermal Energy Storage], VDI-Berichte No. 236, 1975, page 125 to 131). In these known processes, the water which leaves the expansion vessel and is collected in an auxiliary storage vessel is returned to the main store during charging and is thus heated up by the charging steam taken from the main circuit. It is mentioned in the same publication, however, that in principle, the store can be charged from the feedwater circuit. This process which utilizes a separate peak-load turbine, is alleged to have the advantage that the peak-load turbine can be located separately and that, if the store is not charged from the feedwater circuit, the main circuit is almost free from intervention. However, the utilization of the storage capacity is relatively poor in these processes, unless the expansion is carried out in several stages, which requires complicated circuit arrangements.
Overloading the turbine of the power station is regarded as a further possible way of covering peak loads. This can be effected, for example, in such a way that a displacement store completely filled with water is arranged parallel to the feedwater heaters of the plant, which are heated by bled steam, the contents of the displacement store being fed to the steam generator when the load rises suddenly and steeply (Dubbles Taschenbuch fur den Maschinenbau [Handbook of Mechanical Engineering], volume 2, Springer-Verlag, 1961, page 452).
In this way, the bleed points of the turbine are relieved, enabling it to deliver a higher output. This increase in output is, however, limited.
A primary object of the present invention is to provide a process and equipment for carrying out the process, which exhibit the advantages of both the known possible methods of covering peak loads.
In a process of the type outlined above, this is achieved if that part of the stored medium which is not vaporized on expansion is returned in liquid form to the main circuit when the store is discharged and the steam bled from the main circuit to heat the low-pressure feed-heaters is throttled or shut off.
Equipment of the type initially set out is characterized by the fact that the expansion vessel is connected on the water side to the feedwater tank of the main circuit and that at least one condensate vessel, which on the downstream side leads into the low-pressure feed-heater installation of the main circuit, is provided for the condensate from the turbine.
The advantages of the invention are in particular that, with the store fully or partially charged, operation is rendered flexible and immediately adaptable, and a small or very large additional output is obtainable. The latter results from the simultaneous utilization of the liquid and vaporous part of the stored energy carrier.

Thermal energy storage for covering peak loads


A baffle for engine fluid cooling includes a fluid guide having a pair of side walls, a bottom wall, and a coolant fluid inlet. A channel receives a pair of heat exchangers such that one may be positioned proximate to or above a part of the bottom wall and the other may be positioned proximate to or above another part of the bottom wall. Some coolant entering the guide flows into the first heat exchanger and some coolant is passed under the first heat exchanger and subsequently into the second heat exchanger.

Engines, including diesel engines, gasoline engines, and gaseous fuel-powered engines are used to generate a mechanical, hydraulic, or electrical power output. In order to accomplish this power generation, an engine typically combusts a fuel/air mixture. With the purpose to ensure optimum combustion of the fuel/air mixture and to protect components of the engine from damaging extremes, the temperature of the engine and air drawn into the engine for combustion must be tightly controlled. The combustion process typically generates large amounts of heat and, in order to ensure proper and efficient operation of the engine, a cooling system is required to cool fluids directed into or out of the engine, such as, for example, coolant fluid and engine oil. A typical cooling system may have one or more heat exchangers designed to cool the coolant fluid by dissipating heat from the coolant into the atmosphere, and an oil cooler designed to cool the oil by transferring heat from the oil to the coolant fluid.
To accomplish the desired operational temperature control, an internal combustion engine is generally fluidly connected to one or more different liquid-to-air and/or air-to-air heat exchangers to cool both liquids and gases circulated throughout the engine. These heat exchangers are often located close together and/or close to the engine to maximize space efficiency. An engine driven fan or pump may be disposed either in front of the engine/exchanger package to blow air across the exchangers and the engine, or between the exchangers and engine to suck air past the exchangers and blow air past the engine, the airflow removing heat from the heat exchangers and the engine. In other arrangements cooling fluids from the environment, for example water from a marine environment, can be directed through the engine/exchanger package to remove heat therefrom.
One way to ensure proper engine and engine oil temperature is to include multiple heat exchangers in the cooling system. An exemplary heat exchanger arrangement is disclosed in U.S. Pat. No. 6,418,886 to Haimerl et al. In Haimerl, a V-configured internal combustion engine includes a coolant system with multiple heat exchangers. The Haimerl cooling system includes a coolant pump with a coolant inflow line that first directs coolant through a series of heat exchangers or "cooling jackets" disposed externally and to the sides of each of the engine's cylinder banks. The coolant is then directed through the cylinder heads and then through another series of heat exchangers disposed internally, or within the "V", and along the sides of the cylinder banks. The coolant is then guided, upon exiting the internal heat exchangers, back to the coolant pump.
As can be seen from the cooling system in Haimerl, when coolant is directed through a heat exchangers connected in series, the arrangement is not necessarily configured to provide uniform cooling among the tandemly disposed coolers. Specifically, there is at least one potential issue with series-type cooler configurations such as the one in Haimerl, in which coolant fluid (such as, for example, air) is provided at one end of the coolant flow path and passes past each heat exchanger in series as they are disposed within the coolant flow path. In such a configuration the coolant may be warmed by the first heat exchanger prior to exposure to the second heat exchanger along the coolant flow path; and, thus, the efficiently of the second heat exchanger (and any subsequent heat exchangers in the series) may be degraded due to the increased coolant temperature.


A golf club has a shaft made of fiber reinforced plastics. The shaft has braided layers with substantially symmetrical diagonal yarns which are positioned at orientation angles +xcex8, xe2x88x92xcex8 from more than 0xc2x0 to +10xc2x0 and from less than xe2x88x920xc2x0 to xe2x88x9210xc2x0 respectively, and/or from 45xc2x0 to less than +90xc2x0 and from xe2x88x9245xc2x0 to more than xe2x88x9290xc2x0 respectively, against the longitudinal axis of the shaft at at least a portion along the longitudinal direction of the shaft. The Poisson""s ratio xcexd expressed by the ratio of lateral strain to longitudinal strain is 0.5 or less at least at the portion when load is applied to the shaft. The portion with the Poisson""s ratio of 0.5 or less is preferably on the grip side, thus facilitating a swing of the club.

This application claims priority to Japanese Patent Application No. 2000-357858, filed on Nov. 24, 2000.
The present invention relates to a golf club shaft made of fiber-reinforced plastics (FRP), and in particular to a FRP golf club shaft which facilitates a swing by significantly suppressing deformation of the shaft cross section, a golf club having such a shaft, and a novel method for evaluating golf club shafts for deflection.
A golf club shaft made of fiber-reinforced plastics (hereinafter referred to as an xe2x80x98FRP golf club shaftxe2x80x99) is advantageous over a metal golf club shaft as it is lighter than metal one and is easier to accelerate a swing, thereby increasing the flying distance of a ball. Thus, the FRP golf club shaft is extensively employed.
The FRP shaft is a shaft formed of reinforcing fibers impregnated with resin. The FRP shaft includes a shaft fabricated in the sheet-rolling process (SIR shaft), a shaft fabricated in the filament-winding process (FW shaft), and a braided shaft. The S/R shaft is formed by winding unidirectional prepreg sheets made of reinforcing fibers over a mandrel. The FW shaft is formed by winding fiber bundles of reinforcing fibers (yarns) over a mandrel while reciprocating them along the longitudinal axis of the mandrel. The braided shaft is formed by braiding a plurality of fiber bundles of reinforcing fibers (yarns) or tow prepregs (or yarn prepregs) while braiding them over the mandrel to the substantially entire length of the shaft. In manufacturing any of the shafts, the reinforcing fibers may be impregnated with resin before or after winding the fibers around the mandrel.
The conventional FRP shafts, however, suffer from drawbacks in terms of deflection of the shafts during a swing as described below.
Consider the state of the shaft during a swing. The golfer causes generally rotational motion of the head of the club during a swing to hit a ball. During the swing, some possible forces are applied to the shaft, that is, (1) centrifugal force immediately before the impact, (2) inertial force caused by acceleration or deceleration of the head, and (3) impact force immediately after the impact. More specifically, the centrifugal force of (1) is 300 to 500 N which is generated immediately before the impact, when the head speed reaches 40 to 50 m/s. This force pulls the entire shaft in the centrifugal direction of the rotational motion and causes the shaft the bending deformation and tensile deformation. The inertial force of (2) originates in acceleration or deceleration of the head when the golfer rotates, twists, or translates his waist, arms, or wrists. This force applies bending or torsional moment on the shaft, thus causing its bending or torsional deformation. The impact force of (3) is conveyed from the head to the shaft immediately after the impact. This force causes various deformations of the shaft depending on the hitting point of the ball.
An analysis of the force applied to the shaft before the impact, such as the forces (1) and (2), shows that the force may be divided into (A) tensile stress and compression stress symmetrical to the neutral plane that are caused by bonding moment load on the shaft that is applied in the direction of the shaft, (B) tensile stress in the longitudinal direction that is caused by centrifugal force, and (C) shearing force caused by microscopic torsional load, which is negligibly small. The neutral plane of (A) means a virtual plane located along the longitudinal axis of the shaft upon which no tensile stress and compression stress act. Therefore, at a given position in the longitudinal direction of the shaft, deformations are created in the shaft""s longitudinal direction and in the shaft""s circumferential direction due to tensile stress or compression stress. Then the shaft cross section, which generally assumes a circular shape before the swing, deforms elliptically due to collapse or flattening, which sometimes affects the swing or the feeling of the club when the golfer swings it. Furthermore, since the degree of shaft""s deflection is greater in case of golfers who are power hitters or who swing faster, the deflection is especially a serious problem for male professional golfers.
JP-A-11-33151 disclosed an S/R shaft, which materializes light weight and high elasticity and which prevents decreases in strength. Decreases in strength of shaft are prevented by having a high elasticity layer of circumferential fibers in which the fibers are directed in the circumference direction relative to the shaft axis. However, since the thickness of the layer of the circumferential fibers is 0.023 mm and this thickness is relatively thinner compared to that of the entire shaft, resistance against deformation of the layer, or contribution to shaft rigidity, is low. In addition, since this is the S/R shaft, junctions exist at the start of the winding of each reinforcing-fiber sheet and at a location between different sheets (or inter-layer location), which is undesirable in terms of the strength of the shaft.
JP-A-2000-14843 disclosed an S/R shaft using triaxial fabric layers as the reinforcing-fiber layers for providing different required characteristics, such as flexural rigidity, torsional rigidity, and anti-collapse rigidity along the longitudinal direction of the shaft with this shaft, the required characteristics may be satisfied by varying, along the axial direction of the shaft, at least one of following: the fiber density, type of fibers, and the physical properties of tri-directional yarns that constitute the triaxial fabric layers. In fabricating this shaft, triaxial fabric layers are partly overlapped and discontinuously wound over the mandrel along the longitudinal direction of the shaft. This makes the shaft undesirable in terms of the strength.
Conventionally, no index has been established for objectively evaluating the degree of shaft deflection, and the manufacturing of shafts has largely depended on manufacturer""s experience.
The object of the present invention is to provide an FRP golf club shaft that facilitates swing by evaluating shaft deflection caused by the above-mentioned load applied to the shaft on swinging or before the impact, based on Poisson""s ratio, and by suppressing deformation of the shaft cross section as best as possible.
A golf club shaft made of fiber reinforced plastic comprising at least a portion along the longitudinal direction of the shaft which satisfies a Poisson""s ratio of 0.5 or less The Poisson""s ratio is expressed by the ratio of lateral strain to longitudinal strain. The longitudinal strain is the strain in the longitudinal direction of the shaft and the lateral strain is the strain in the circumferential direction of the shaft when load is applied to the shaft.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.


A recent secure authentication service enforcing revocation in distributed systems is provided. Authenticity entities impose freshness constraints, derived from initial policy assumptions and authentic statements made by trusted intermediaries, in authenticated statements made by intermediaries. If freshness constraints are not presented, authentication is questionable. The freshness constraints can be adjusted. The delay for revocation can be arbitrarily bounded. The freshness constraints within certificates results in a secure and highly available revocation service such that less trust is required of the service.

Authentication architecture that scales globally is desirable to support authentication and authorization in electronic commerce. A characteristic of universal electronic commerce is that clients and commercial servers not previously known to one another must interact. An essential feature of an authentication service in large distributed systems is revocation. Revocation entails rescinding authentication and authorization statements that have become invalid. Revocation is needed because authentication information changes with time due to a compromise or suspected compromise of an entity's private key, a change of affiliation, or a cessation of an entity's operation. When a compromise is discovered, rapid revocation of information is required to prevent unauthorized use of resources and electronic fraud.
Revocation usually has the following properties. It should be fail-safe or assured with bounded delays, i.e., it should be definite. The mechanism for posting and retrieving updates must be highly available, and retrieved information should be recent if not current. Protection and performance trade-offs should be adjustable to suit varying risk adversity. When a compromise is discovered, delays in revocation should be decidedly bounded in time. A compromised revocation service should not allow illegitimate identification credentials to be issued.
However, there are factors which make revocation in a large distributed environment difficult. These factors include size, trust, security, the distributed nature of the system and the temporal dynamics of the system. That is, numerous entities not previously known to one another may need to interact securely. Entities have different views of the trustworthiness of intermediaries and of each other. Protection of computing environments is variable and uncertain. The authenticating entity's knowledge of authentication information can be inaccurate due to communication latency, failures, and active wiretapping. In addition, authentication and authorization information changes with time and is unpredictable.
There is little in the art focusing on revocation and validity assertions in large distributed systems. Kerberos and DCE (based on Kerberos) have been used in local autonomous realms in large distributed systems. However, shared secret crypto-systems such as these have inherent drawbacks when scaling to a large distributed system.
Authentication in large distributed systems is moving toward the integration of local network authentication servers with global directories (e.g., those based on the X.500 directory) and open authentication architectures (e.g., those based on the X.509 directory) using public key cryptography.
Global authentication architectures based on public key cryptography assume that named principals to be authenticated maintain the confidentiality of their private keys. Certificates using public key cryptography enable authentication information of the authority of the certificate contents to be distributed using servers that need not be trusted. Intermediaries, called certifiers or certification authorities (when authority is assumed by authenticating entities), create cryptographically protected statements called certificates. Identification authorities, having authority in identification of entities, issue identification certificates. Identification certificates assert that a public key is associated with an entity having a unique name. Revocation authorities, having authority on the status of certificates, issue revocation certificates. Revocation certificates assert the status of certificates previously issued. Revocation policies, which are typically included in authentication policies, represent a bounded delay before an authentication entity becomes current on the accuracy of authentication information. Authentication conforming to these policies is called recent-secure authentication. The entity or agent doing the authentication is called the authenticating entity. Propagation of certificates through servers, such as directory servers, can introduce delays.
As noted above, Kerberos is a distributed authentication service that allows a process (client) running on behalf of a principal (user) to prove its identity to a verifier (an application server or just a server) without sending data across the network that might allow an attacker or verifier to subsequently impersonate the principal. Kerberos can also provide integrity and confidentiality for data sent between the server and client. However, Kerberos does not protect all messages sent between two computers. It only protects the messages from software that have been written or modified to use it. Kerberos uses a series of encrypted messages to prove to a verifier that a client is running on behalf of a particular user. The service includes using "time stamps" to reduce the number of subsequent messages needed for basic authentication and a "ticket-granting" service to support subsequent authentication without reentry of a principal's password. It should be noted that Kerberos does not provide authorization, but passes authorization information generated by other services. Therefore it is used as a base for building separate distributed authorization services.
Recent-secure authentication is based on specified freshness constraints for statements made by trusted intermediaries (certifiers) and by principals that may be authenticated. These statements represent assertions regarding whose authenticity can be protected using a variety of mechanisms ranging from public or shared-key to physical protection. Freshness constraints restrict the useful age of statements. They can come from initial authentication assumptions and can also be derived from authentic statements which may themselves be subject to freshness constraints.
An important requirement of revocation in large distributed systems is the fail-safe property. This means that revocation is resilient to unreliable communication. Revocation mechanisms not satisfying this property can be impeded by active attacks in which the adversary prevents the reception of revocation statements. Apparent countermeasures to these attacks may not be adequate. For example, consider the technique of cascaded delegation where a delegation certificate is created as a delegation is passed to each new system. To terminate a delegation, a "tear down" order is passed down the chain. However, due to unreliable communication or a compromise of an intermediate system, the order may not fully propagate. To remedy this, it has been proposed that each intermediate delegate periodically authenticate delegates. However, periodic authentication of predecessor delegates can be vulnerable to attacks where the adversary steps down the chain blocking revocation statements until the particular link times out. The result is an additive effect on delaying revocation. Alternatively, each node could authenticate every other node at the cost of n2 messages, where n is the number of nodes. The optimal design for balancing performance and security depends on the protection of each system and the communication therebetween.
Communication latency is an inherent property of distributed systems. Consequently, authenticating entities cannot have perfect knowledge of authentication and authorization information. Therefore, failure can occur. The problem is compounded in large distributed systems. Additional certifiers represent more distributed knowledge.
Obtaining consistent knowledge of authentication data is difficult and prohibitively expensive. It is therefore necessary to quantify levels of protection that can be obtained and to reason whether they have been obtained. The practical significance of recent-secure authentication is that it enables distributed authenticating entities on a per-transaction basis to trade-off authentication costs against the level of protection.
In addition, quantifiable authentication assurances are difficult to provide if information about the intermediate system is incomplete. In spite of this, many systems operate with incomplete information. This requires the risk of operating such systems to be periodically reassessed. That is, entire industries have been dependent on reassessing shifting risks. Recent-secure authentication policies are an important variable for reassessing risk in large distributed systems. For example, proposals have been made to assign financial liability attributes to certificate authority statements in financial systems based on shifting risk.
A number of other related techniques have been proposed for effecting revocation in distributed systems. These techniques will be briefly reviewed.
With respect to certificate caches with exception notifications, authenticating entities may cache certificates and notify caches when there is a change. This approach is not well suited to large distributed systems since the notification mechanism is not fail-safe For example, an adversary could selectively block an exception notification. Also, it does not scale well if the destination caches need to be tracked. However, emergency notifications can augment a fail-safe scheme to possible shorten revocation delays provided messages reach their destinations sooner than the time-out periods. A distributed multicast infrastructure could alleviate the load on servers for distribution of notifications.
With respect to certificates having expiration times, a common technique for bounding the delay of revocation is placing explicit expiration times within certification. Statements using expiration times satisfy the fail-safe property provided that a certifier has not been compromised. Since authentication can depend on trusted intermediaries, an entity might be vulnerable to illegitimate statements made by a compromised certifier. Consequently, neither the certifier nor the authenticating entity can be assured that it or its subordinates have not been cloned due to a compromise of an arbitrary certifier that is trusted by an authenticating entity.
On-line servers and quorum schemes have been proposed whereby entities issue queries in an authenticated exchange to learn the validity of authentication/authorization information. Use of on-line servers may be justified in architectures where the server is local to the source or destination. However, network failures can significantly impact the availability of such servers for geographically distributed clients.
Replicating trusted servers for increasing availability inherently increases the risk of compromising the secret keys held by the server. Secret sharing techniques can improve availability and security, but they do so at the expense of considerable communication costs and increased delay. For example, the effective time of the statement from the quorum might be the earliest statement time in a final round used to make the decision. Due to communication costs and increased delay, geographic distribution of secret sharing servers, for the purposes of surviving network failures, may not be practical for most applications.
With respect to long-lived certificates and periodic revocation statements, revocation methods have been proposed where authorities issue long-term identification certificates and periodically publish time stamped revocation certificates. Revocation certificates can be distributed to the authenticating entity through untrusted communications.
The scalableness of this approach depends on whether servers are replicated. However, replicating the trusted identification authority inherently decreases security. In this case, a compromised server may enable an adversary to issue new identification certificates.
With respect to off-line identification authority and on-line revocation authority, an approach for increasing the availability and security of an authentication service calls for joint authorities. An off-line identification authority generates long-term certificates and an on-line revocation authority creates countersigned certificates with short lifetimes. The effective lifetime is the minimum lifetime of both certificates.
The joint authority approach benefits from the fact that the compromise of the on-line server does not enable the adversary to issue new identification certificates. As expected, a compromised revocation authority could delay revocation until the authority of the on-line server expires. However, the period of compromise may be extended further if the revocation authority issues revocation certificates with longer lifetimes.
An alternative approach to creating countersigned certificates is to authenticate a channel to an on-line (trusted) database server and to retrieve original certificates. However, authenticated retrieval of certificates alone may be insufficient to provide adequate assurance that a certificate is current. For example, when providing high availability for geographically distributed clients, the revocation service might replicate the database and use optimistic consistency control techniques. These techniques do not guarantee the consistency of stored certificates at the time of retrieval. Consequently, the presence of a certificate in a local replica might represent stale information. Additional delays occur as certificates are exported to trusted subsystems for local retrieval. Also, the on-line revocation server/database is subject to the scaling limitations inherent to on-line servers as discussed above.
As set forth above, neither Kerberos nor any other authentication system focuses on revocation and validity of assertions in large distributed systems. These prior systems all have inherent problems regarding revocation in complex systems.

Specifying security protocols and policy constraints in distributed systems


The present invention relates to a photoelectrographic element having a conductive layer in electrical contact with a acid photogenerating layer which is free of photopolymerizable materials and contains an acid photogenerator, a pigment which absorbs near-infrared radiation, and, preferably, an electrically insulating binder. Contiguous with the acid photogenerating layer is a charge transport layer formed from a polymeric binder and one or more charge transport materials. A process for forming images with this element is also disclosed.

Electrophotographic compositions and imaging processes are well known. In such processes, an electrophotographic element, having a photoconductive layer, is electrostatically charged and then imagewise exposed to form a latent electrostatic image. The latent electrostatic image is subsequently developed with a toner composition.
Various types of photoconductive insulating materials are known for use in electrophotographic imaging processes. In many conventional electrophotographic elements, the photoconductive insulating material is in a single layer composition affixed to a conductive support.
In addition, various multi-active electrophotographic elements (i.e. those having more than one active layer) have been described in the art. See e.g., U.S. Pat. No. 3,165,403 to Hoesterey. One layer, known as the charge generation layer, is affixed to the conductive support and generates charge carriers when exposed. Also present is a charge transport layer through which charge carriers which are generated in the adjacent charge generation layer pass in moving to the charged surface of the element.
Electrophotographic processes suffer from the deficiency of having to repeat the exposing step each time a copy is made. This is uneconomical and inefficient when producing multiple copies of a single document. As a result, photoelectrographic elements have been developed to produce multiple copies from a single exposure. See e.g., U.S. Pat. Nos. 4,661,429 and 3,681,066 as well as German Democratic Republic Patent No. 226,067 and Japanese Patent No. 105,260.
Acid photogenerators have been employed in photoelectrographic elements to be exposed with actinic or undefined radiation as shown, for example, in U.S. Pat. No. 3,316,088. Sensitizer dyes have been disclosed with regard to such elements, but not for sensitization in the near-IR portion of the spectrum. See, for example, in U.S. Pat. No. 3,525,612 and Japanese Patent No. 280,793.

Photoelectrographic imaging with a multi-active element containing near-infrared sensitizing pigments


A burner assembly is provided that includes a burner pan having a peripheral portion adapted to engage a range top at the periphery of a burner opening and a sealed burner in central portion of the burner pan. A resilient elastic seal straddles the peripheral portion of the burner pan so as to be disposed between the burner pan and the range top and between the burner pan and the burner grate. The elastic seal retains the burner grate in position slightly above the range top and provides a seal to close the burner opening.

Prior art burner assemblies, and particularly prior art sealed gas burner assemblies have not been entirely satisfactory. It is desirable to provide "sealed burners" on cooking ranges. A primary requirement in the design of sealed burners is the prevention of liquid or other spills from leaking into the burner box interior. It is, therefore, common practice within the industry to provide "pan seals" to prevent leakage of spills into the burner box interior. The seal is usually either a closed loop, physically joined at its extremities, or a non-contiguous seal, unjoined at its extremities. Typically, the pan seals are loosely retained below and along the perimeter of the burner pan. The loose application may be at the perimeter of the burner pan itself or at the perimeter of the opening of the metallic or glass range top in which the burner pan is located.
Because of the loose application of the seal, sealed burner pans typically require a perimetral flange to align and retain the seal. Unfortunately, the perimetral flange increases the tooling expense and therefore the cost of the burner pan. Also, in conventional burner pans, there is a need for good porcelain coverage and good porcelain adherence at the circumference of the burner pan to avoid corrosion and degradation of appearances. The presence of a perimetral flange increases the difficulty of obtaining and maintaining the porcelain enamel coating of the burner pan. A further problem is heat transfer between the burner and grate and seal, particularly with sealed gas burners.
Another problem associated with conventional burner assemblies is the "clunk" sound made when the burner grates are put down on the burner pan and rangetop, which is an irritant to consumers. The invention addresses these problems and others, as will be apparent to those skilled in the art from the drawings and description that follows.


Apparatus is disclosed for providing one hundred percent inspection of natural gas mains under operating flow conditions. The apparatus includes a scan unit assembly which is inserted into the gas main to collect data for the production of graphic images of the wall of the gas main. The scan unit includes a plurality of scan rollers, each containing an ultrasonic transducer, which traverse the surface of the wall defining the inner diameter of the gas main. The ultrasonic transducers transmit interrogating pulses into the wall of the gas main at a pre-determined spaced apart interval resulting in a helical scan pattern of interrogating pulses. The return pulses from the surfaces defining the inner diameter and outer diameter of the gas main and any imperfections and/or flaws within the wall of the main are received by the transducer and transmitted to a display unit for a visual indication (a tomograph) of the wall of the gas main.

Thousands of miles of buried natural gas mains of varying sizes and formed from various materials are presently in service. All of these mains are in some state of progressive degradation. In most instances, the extent of such degradation is unknown, and hence, the serviceability of the mains is similarly unknown. This lack of information with respect to degree of degradation results in unforseen gas main breaks and/or leaks, and necessitates the expending of substantial time and expense in locating these defects so that repairs and/or replacement can be made. Because of the need to detect conditions which might result in gas main breaks and/or leaks, apparatus has been developed for inspecting gas mains, and such apparatus is usually referred to as a pipe line "pig". Such pipe line "pigs" typically include a housing with a plurality of sensors mounted on the outer surface thereof in a pre-determined configuration or array to contact the inner surface of the gas main. Since the sensors are in a pre-determined configuration or array, one hundred percent inspection of the wall of the gas main is generally not possible, i.e., the portion of the wall between two adjacent sensors is typically not inspected. Achieving one hundred percent inspection of the wall of the gas main by utilizing such apparatus is generally not possible, and to approach one hundred percent inspection of the wall would require an inordinate number of sensors.
In view of the foregoing, it has become desirable to develop apparatus that provides one hundred percent inspection of the walls of gas mains under operating flow conditions and a method of assessing the serviceability of buried gas mains and recording the data for future reference and analysis. With this capability, natural gas utilities can monitor the rate of degradation of gas mains and plan repairs and/or replacements before failures occur.


A thermoplastic multi-layer film with an even number of layers containing first and second outermost layers each containing ethylene-vinyl acetate copolymer having between 14 and 22 wt. % vinyl acetate, first and second inner layers each containing vinylidene chloride copolymer, and first and second contiguous layers separating first and second inner layers from each other, each layer containing ethylene-vinyl acetate copolymer.

The present invention refers to an RF-sealable pillow pouch of a thermoplastic material particularly suitable for packaging flowable products and to a method of packaging said product in a vertical form-fill-seal machine using an RF sealable, thermoplastic material.
Flowable products, such as powders, liquid and pasty materials, e.g. detergents, liquid soaps, household cleaning products, bleaches, etc., are currently packaged in so called pillow pouches made of PVC. These pillow pouches are typically used as monodose packages or as refill cartridges that are opened and poured in a re-usable rigid or semi-rigid container as desired.
The machine that makes and fills packages in a single operation is called a vertical form-fill-seal (VFFS) machine. Said machine forms pouches from a web of flat flexible film while filling them with the product. The film is fed from a roll to a device that forms it into a tube of a suitable diameter around the product filling tube. The two film edges are then sealed together, longitudinally, either with a lap seal or with a fin seal. As the tube moves down the machine, two horizontal sealing bars come together to form a transverse seal which becomes the bottom of the pouch. At that point, a measured amount of product is allowed to flow through the product filling tube and into the just formed pouch. By the time filling is complete, the top of the pouch has traveled down to the sealing bar location, where the bars once again meet to simultaneously create the top seal and the bottom seal of the next pouch above. Alternatively, it is also possible to manufacture the pillow pouches in two separate steps, where the first step is the production of the pouches by any conventional system and the second one is the pouch filling In a vertical machine followed by the sealing of the pouch mouth.
Pillow pouches are characterized in that at least one of the transverse sealing is a melt cut sealing. The melt cut sealing Is a sealing carried out with heating while at the same time the film is pressed and cut. The sealing bars are therefore equipped with a knie which cuts through the seal to separate the filled pouch from the machine. To give the appearance of a pillow, as the name does suggest, once the pouch is filled with the metered volume of flowable product, generally of the liquid or pasty product, air or a suitable gas is injected before the transverse sealing bars are pressed together.
Working with PVC at least the transverse sealing system in these VFFS machines is based on dielectric heating or RF heating. In this system high frequency electric current is passed through the film by the sealing bars. When the film contains polar molecules, as in the case of PVC, these molecules oscillate under the influence of the current and this molecular agitation is converted to heat sufficient to melt the film in the seal area.
The advantages of xe2x80x9cpillow pouchesxe2x80x9d are obvious: reduced volume, reduced consumption and waste of plastic material, lower cost, etc.
However the use of PVC, that up to now has been considered the polymer of choice for this application, presents many drawbacks.
First of all PVC has no gas-barrier and moisture-barrier characteristics. Volatile components, e.g. perfumes, aromas, etc., can easily escape through the packaging material, thus reducing the content thereof in the packaged product and, when these components have an unpleasant smell, e. g. in case of bleaches, imparting said smell to the whole package. Water also can evaporate through the PVC layer thus reducing the volume of the packaged product and increasing the concentration of the non volatile components therein.
Secondly, PVC generally contains a high level of plasticizers. Said plasticizers do easily migrate Into the packaged product with a consequent package integrity problem. The mechanical properties of PVC films in fact are determined by the level of plasticizers: a decrease In the amount of plasticizers due to their migration into the packaged product will increase the stiffness and brittleness of PVC thus reducing its mechanical (puncture, abuse) resistance.
A third disadvantage of the use of thick PVC films is the amount of chlorine containing polymer that needs to be disposed of.
PVC replacement in the manufacture of pillow pouches for the packaging of flowable products has been widely described in the patent literature.
Of interest is EP-B-477,025 that describes the use of a multilayer film having a barrier layer of a thermoplastic material, preferably an LLDPE or a composite of a polyethylene layer and a polyamide or EVOH layer, and on at least one side thereof a layer of an RF-sealable polymer, e.g. EVA with a high VA content According to EP-B-77,025, the problem created by the low RF-sensitivity of the thermoplastic barrier materials is overcome by the use of sealing layers of EVA with a high VA content and a low, controlled, content of additives, while the problem of sticking that derives from the use of such a sealing layer is overcome by the use of structures with a matted surface. These structures do not contain chlorine and have moisture barrier properties, however they do not overcome the other drawbacks connected with the use of PVC as for instance the structures described In EP-B-477,025 do not have odour-barrier properties or only to a limited extent While in fact polyethylene and polyamide have no or moderate odor barrier properties, EVOH is very sensitive to moisture and its odor barrier properties, that are satisfactory under dry conditions, are drastically reduced after exposure to a moistured environment. Furthermore, owing to the low RF-sensitivity of these barrier materials, and depending on their thickness, the seal strength of the RF-seal may sometimes be unsatisfactory in spite of the high VA content of the EVA sealing layer. Finally, with these structures an additional step in the film manufacturing process is required to provide the matted surface, what adds an extra-cost to the film.
Also of Interest is EP-A-471,607 that describes RF-sealable thermoplastic films particularly suitable for packaging gas-emitting flowable products. Said films comprise a core polyolefin layer and EVA sealing layers and are characterized by an oxygen transmission rate (OTR) of at least about 600 cm3/m2.d.atm. This high OTR is required, according to EP-A-471,607, because in packaging gas-emitting products, such as bleaches, a gas, typically oxygen, is evolved during storage and should be allowed to be dissipated through the pouch wall to avoid that pressure builds up into the pouch and the pouch seal breaks.
Also the structure described in EP-A-471,607 does not contain chlorine and has moisture barrier properties but it has no odor barrier properties. Furthermore, also in this case, the presence of a thick core layer of polyolefin material with a low RF sensitivity affects the RF sealability of the overall structure. It is probably due to the low seal strength of the thus obtained RF-seal that such a high OTR is needed to avoid breaking of the seal.
It has now been found that It Is possible to solve the above problems in a satisfactory way by using, as PVC replacement in the manufacture of said pillow pouches, a film comprising an RF-sealable outer layer of ethylene-vinyl acetate copolymer with from about 14 to about 28 wt. % of VA and a layer of PVDC.
The use of such a film as a PVC replacement offers many advantages as the RF-seal will have a good seal strength because the presence of a PVDC layer improves the sealability of the overall structure; it has also been found that the presence of a PVDC layer imparts to the pouch the desired balance of stiffness and flexibility so that films 75-150 xcexcm thick can be run in the commercial VFFS machines giving a better performance than conventional 200-250 xcexcm thick PVC films, and thus drastically reducing the amount of plastic material per package which needs to be disposed of after use; the amount of chlorine containing polymer is highly reduced as the PVDC layer will be only few micron thick while PVC pouches generally require a 200-250 xcexcm-thick sheet Furthermore, by suitably selecting the thickness and/or composition of the PVDC layer it is possible to xe2x80x9cmodulatexe2x80x9d the gas- and odor-barrier properties of the end structure to the desired extent.
In accordance with the present invention, there is provided a coextruded thermoplastic multilayer barrier film with an even number of layers, comprising first and second outermost layers each comprising ethylene-vinyl acetate copolymer, first and second inner layers each comprising vinylidene chloride, and first and second contiguous layers separating first and second inner layers from each other, each layer comprising ethylene-vinyl acetate copolymer. Preferably, the outermost layers of ethylene-vinyl acetate have a vinyl acetate content between 14 and 22 wt. %, and the contiguous layers of ethylene-vinyl acetate have a vinyl acetate content from 22 to 28 wt. %. The barrier film is a layflat tubular film having its interior layflat surfaces laminated together by self-welding.
As used herein, the term xe2x80x9chomopolymerxe2x80x9d is used with reference to a polymer resulting from the polymerization of a single monomer, i.e., a polymer consisting essentially of a single type of repeating unit.
As used herein, the term xe2x80x9ccopolymerxe2x80x9d refers to polymers formed by the polymerization reaction of at least two different monomers.
As used herein, the term xe2x80x9cpolymerxe2x80x9d refers to both homo-polymers and co-polymers as defined above.
As used herein the term xe2x80x9cethylene homopolymersxe2x80x9d identifies polymers consisting essentially of an ethylene repeating unit
As used herein, the phrase xe2x80x9cethylene xcex1-olefin copolymerxe2x80x9d, and xe2x80x9cethyieneolxcex1-olefin copolymerxe2x80x9d, refer to such heterogeneous materials as linear low density polyethylene (LLDPE), linear medium density polyethylene (LMDPE) and very low and ultra low density polyethylene (VLDPE and ULDPE); and homogeneous polymers such as metallocene catalyzed polymers such as EXACT(trademark) materials supplied by Exxon, AFFINITY(trademark) and ENGAGE(trademark) materials supplied by Dow, LUFLEXEN(trademark) materials supplied by BASF and TAFMER(trademark) materials supplied by Mitsui Petrochemical Corporation. These materials generally Include copolymers of ethylene with one or more comonomers selected from C4 to C10 xcex1-olefins such as butene-1 (i.e., 1-butene), hexene-1, octene-1, etc.
As used herein the term xe2x80x9cethylene-ethylenically unsaturated ester copolymerxe2x80x9d refers to the copolymers of ethylene with one or more ester comonomers containing a vinyl group such as ethylenelvinyl acetate copolymers, ethylenelethyl acrylate copolymers, ethylenelbutyl acrylate copolymers, ethylenelmethyl acrylate, ethylenelme thyl methacrylate copolymers.
As used herein, the phrase xe2x80x9cmodifled polymerxe2x80x9d, as well as more specific phrases such as xe2x80x9cmodified ethylene vinyl acetate copolymerxe2x80x9d, refer to such polymers having an acid or, preferably, an anhydride functionality, such as maleic or fumaric anhydride or acid, grafted thereon and/or copolymerized therewith and/or blended therewith. Preferably, such modified polymers have the anhydride functionality grafted on or polymerized therewith, as opposed to merely blended therewith.
As used herein, xe2x80x9cPVDCxe2x80x9d refers to a vinylidene chloride copolymer wherein a major amount of the copolymer comprises vinylidene chloride and a minor amount of the copolymer comprises one or more unsaturated monomers copolymerizable therewith, typically vinyl chloride, and alkyl acrylates (e.g. methyl acrylate) or to a blend thereof in different proportions. This term also includes the co-polymer(s) when blended with additives, such as stabilizers, plasticisers, etc., as known in the art.
As used herein, the phrase xe2x80x9cdirectly adheredxe2x80x9d, as applied to film layers, is defined as adhesion of the subject film layer to the object film layer, without a tie layer, adhesive, or other layer therebetween. As used herein xe2x80x9ccontiguousxe2x80x9d, when referred to two layers, is intended to refer to two layers that are directly adhered one to the other. In contrast, as used herein, the word xe2x80x9cbetweenxe2x80x9d, as applied to a film layer expressed as being between two other specified layers, includes both direct adherence of the subject layer to the two other layers it is between, as well as lack of direct adherence to either or both of the two other layers the subject layer is between, i.e., one or more additional layers can be imposed between the subject layer and one or more of the layers the subject layer is between.
As used herein, the phrases xe2x80x9cinner layerxe2x80x9d and xe2x80x9cinternal layerxe2x80x9d refer to any film layer having both of its principal surfaces directly adhered to another layer of the film.
As used herein, the phrase xe2x80x9couter layerxe2x80x9d refers to any film layer having only one of its principal surfaces directly adhered to another layer of the film.
As used herein, the term xe2x80x9ccorexe2x80x9d, and the phrase xe2x80x9ccore layerxe2x80x9d refer to any internal film layer which has a primary function other than serving as an adhesive or compatibilizer for adhering two layers to one another.
As used herein, the phrase xe2x80x9cbulk layerxe2x80x9d refers to any layer which is present for the purpose of improving the abuse-resistance, toughness, modulus, etc., of the film. Bulk layers generally comprise polymers which are inexpensive relative to other polymers in the film which provide some specific purpose unrelated to abuse-resistance, modulus, etc.
As used herein, the phrase xe2x80x9ctie layerxe2x80x9d refers to any internal layer having the primary purpose of adhering two layers to one another.
A first object of the present invention is a pillow pouch containing a flowable product characterized in that the packaging material is a thermoplastic film comprising an RF sealable outer layer of EVA containing from about 14 to about 28 wt. % VA and a layer of PVDC.
As used herein the term xe2x80x9ca layer of EVAxe2x80x9d is used to mean that the base thermoplastic material of the layer is essentially EVA. In the EVA layer the thermoplastic material may however contain the conventional anti-block and slip agents, such as silica, either natural or synthetic silica, calcium stearate, amides or bis-amides, etc., opacifying agents, e.g. CaCO3, pigments, e.g. TiO2, UV absorbers, etc. as known in the art. These additives can be added up to about 30 wt. %, preferably however they are limited to a maximum of about 20%, and more preferably to a maximum of 15 wt. %, calculated on the weight of the RF-sealable outer layer. Generally anti-block and slip agents are added to the sealing layer in an amount up to about 10 wt. %, typically up to 8 wt. %, while a higher amount of opacifying agents and pigments, up to about 20 wt. %, can be employed without problems. As used herein xe2x80x9cessentially EVAxe2x80x9d does not exclude the presence of minor proportions, e.g. up to less than about 10%, of other thermoplastic materials provided said materials do not impair the RF-sealability of said outer layer. Examples of thermoplastic materials that might be present In minor proportions in the outer RF-sealable layer of EVA are ethylenemethylacrylate, ethylene-ethylacrylate, ethylene-butylacrylate copolymers, PVDC, and the like polar polymers. In a preferred embodiment however the base thermoplastic material of the EVA layer is only EVA.
Preferably, the thermoplastic film to be used in the manufacture of pillow pouches according to the present invention, has a sealing layer of an ethylene-vinyl acetate copolymer containing at least 16 wt. % of vinyl acetate. More preferably said ethylene-vinyl acetate copolymer will contain from about 16 to about 22 wt % VA. While ethylene-vinyl acetate copolymers with a VA content lower than 14 wt. % are hardly RF-sealable, ethylene-vinyl acetate copolymers with more than 22 wt. % VA are RF sealable but they are generally very soft and sticky and may create some difficulties when used as the outer layers in a structure to be run on a conventional VFFS machine.
When used in applications where high odor- and gas-barrier properties are required, the film will typically have an Oxygen Transmission Rate (OTR) lower than 50 cm3/m2.d.atm, when measured at 23xc2x0 C. and 0% or 100% of relative humidity, and a moisture vapour transmission rate (or MVTR) xe2x89xa625 g/m2.d when measured at 38xc2x0 C. and 98% of relative humidity.
While the OTR is evaluated by following the method described in ASTM D-3985 and using an OX-TRAN instrument by Mocon, the MVTR is measured by ASTM F-1249 using a Permatran W-1 instrument by Mocon.
This can be easily obtained using a PVDC with a low content of plasticisers. In such a case, the thickness of PVDC can be as low as 3 xcexcm still providing for optimum gas- and odour-barrier properties, but preferably it is at least 5 xcexcm, and typically it is comprised between about 5 and about 25 xcexcm. These PVDC with a low content of plasticisers are those conventionally employed in the food packaging area to obtain high oxygen barrier properties.
On the other hand when used for packaging gas-emitting products the film will typically have an OTR of at least about 100 cm3/m2.d.atm, preferably of at least 120 cm3/m2.d.atm, and even more preferably of at least 150 cm3/m2.d.atm.
Such a high OTR can be obtained in a PVDC containing structure by reducing the thickness of PVDC andlor increasing the amount of plasticisers blended therein. It is in fact widely known that the oxygen permeability of PVDC increases with increasing plasticiser content
Additives that can satisfactorily be employed to increase the OTR of the PVDC layer comprise the plasticizers conventionally employed, in small amounts, as processing aids for high-barrier PVDC, such as epoxy compounds, e.g. epoxidized linseed oil, epoxidized soybean oil, epoxy resins (such as for instance EPON 828 by Shell), alkyl esters, such as dibutyl sebacate, acetal tributyl citrate, phosphates, such as 2-ethyl hexyl diphenyl phosphate (sold by Monsanto as Santicizer-141), phenoxypropylene oxide, EVA with a wt, % VA higher than 15 (such as the Elvax(trademark) resins by DuPont), modified EVA (such as the Elvaloy(trademark) resins sold by DuPont), impact modifiers such as chlorinated polyethylene, butyl rubber, chloro-butyl rubber, ethylene-propylene rubber (EPM), elastomeric terpolymer from ethylene, propylene and a conjugated diene (EPDM), polyisobutylene, styrene-butadiene copolymers, etc.
The amount of plasticizer(s) to be added to the PVDC resin depends on the desired OTR and on the PVDC thickness in the overall structure. Generally, however, it becomes difficult to blend the PVDC resin with the liquid plasticizer(s), such as the epoxidised linseed oil, the epoxidised soybean oil, the epoxy resins and the alkyl esters, when the amount thereof is higher than 16-20 wt. %. Typically therefore the amount of liquid plasticizer(s) in the PVDC blend will be up to about 15 wt. %, preferably from about 1 wt. % up to about 10 wt. %, more preferably from about 3 wt. % up to about 8 wt. %. Solid plasticizers, such as EVA, modified EVA, impact modifiers, e.g. those listed above, can be admixed to the PVDC up to about 50 wt. %, preferably up to about 40 wt. % and more preferably up to about 30 wt. %. Solid and liquid plasticizers can also be employed in combination. In such a case the PVDC powder is first thoroughly blended with the solid plasticizer(s), in powder form, and then the liquid plasticizer(s) is blended thereto.
Other additives, such as stabilizers, UV absorbers, deodorizers, antioxidizers, etc. can be added to the PVDC resin. These other additives are generally used in minor amounts, typically up to about 2 wt %.
To increase the film OTR the thickness of the PVDC can be reduced down to about 1 xcexcm. Conventional thickness, e.g. 3, 5, 10 xcexcm, or even more, may however provide the desired OTR depending on the amount and type of plasticisers contained therein.
Preferably the film according to the invention has at least 3 layers, wherein the PVDC layer is a core layer and the other outer layer, that may be involved in the longitudinal sealing in case of lap seals, is also of ethylene-vinyl acetate copolymer with from about 14 to about 28 wt. % of VA.
Other layers may be present in the film such as tie layers or bulk layers. Suitable bulk layers will comprise ethylene-ethylenically unsaturated ester copolymers, preferably ethylene-vinyl acetate copolymer, polyethylene homopolymers or ethylene-xcex1-olefin copolymers, provided the RF sealability of the structure is maintained.
Suitable tie layers may comprise modified ethylene-vinyl acetate copolymers or modified polyethylenes.
In a preferred embodiment the thermoplastic film to be used in the manufacture of pillow pouches according to the present invention will comprise at least 5 layers with at least one core layer of PVDC, outer layers of ethylene-vinyl acetate copolymers with from about 14 wt. % VA, preferably about 16 wt. % VA, to about 28 wt. % VA and Intermediate tie layers comprising optionally modified ethylene-vinyl acetate copolymers.
As indicated above, thermoplastic films 75-150 xcexcm thick could replace PVC in the current VFFS machines and provide a better performance than the conventional 250 xcexcm thick PVC film used in these machines. Thicker films can however be employed for highly demanding applications or thinner films for very small pouches. Generally, the thickness of suitable films may range from about 50 to about 250 xcexcm, preferably it will range from about 70 to about 200 xcexcm, more preferably from about 75 to about 150 xcexcm.
The thickness of the sealing layer is generally at least 10 xcexcm, preferably it is at least 20 xcexcm, and even more preferably at least 30 xcexcm. As the polymer used for the sealing layer may also be used to provide the desired thickness to the film, in some instances very thick sealing layers will be present, such as in the case of a 3-layer structure.
The thermoplastic film suitable for use in the manufacture of pillow pouches according to the present invention is generally obtained by coextrusion. The film is not stretched or oriented, at least intentionally. A slight orientation, so-called accidental orientation, may be present depending on the production method employed.
A preferred method of manufacture thereof is the hot blown method.
Alternatively it is possible also to use the cast extrusion method, either through a round or preferably through a flat die. The cast extrusion method also allows to obtain the film by extrusion coating.
In a most preferred embodiment the film will be obtained by the bubble collapse technique that provides for collapsing the bubble obtained by the hot blown method, when the resin inside is still hot, and pressing it so as to obtain a single web with a thickness twice that of the extruded film and an even number of layers with two separate PVDC layers. Said preferred film may for instance comprise 6, 8, or 10 layers, preferably 6 or 10. To improve adhesion between the two innermost layers of the coextruded film of the bubble, preferably an ethylene-vinyl acetate copolymer with a high content of VA is employed, such as an ethylene-vinyl acetate copolymer with from about 16 to about 35 wt. % VA, preferably from about 18 to about 32 wt. % VA, more preferably from about 22 to about 28 wt % VA.
The films obtained by this method are particularly suitable as PVC replacement in the manufacture of pillow pouches. The presence of two separate PVDC layers further improves the desired balance between stiffness and flexibility, while the manufacturing cost is reduced because the ply separation step is avoided.
A second object of the present invention is therefore a symmetrical thermoplastic film with an even number of layers, outer layers comprising an ethylene-vinyl acetate copolymer with from about 14 to about 28 wt. % of VA and two PVDC inner layers, separated by at least two contiguous layers comprising ethylene-vinyl acetate copolymer.
Preferably said symmetrical structure will have a thickness of at least about 50 xcexcm, more preferably at least about 70 xcexcm, and even more preferably at least about 75 xcexcm.
In a preferred embodiment at least two contiguous layers inbetween the two PVDC layers in said symmetrical structure comprise ethylene-vinyl acetate copolymer with from about 16 to about 35 wt. % VA, preferably from about 18 to about 32 wt. % VA, more preferably from about 22 to about 28 wt. % VA.
Preferred symmetrical structures will comprise outer layers of ethylene-vinyl acetate copolymer with from about 14 to about 28 wt. % of VA and two PVDC inner layers, separated by at least two contiguous layers of ethylene-vinyl acetate copolymer with from about 22 to about 28 wt. % VA.
A third object of the present invention is a symmetrical thermoplastic film with an even number of layers, outer layers comprising an ethylene-vinyl acetate copolymer with from about 14 to about 28 wt. % of VA and two PVDC inner layers, separated by at least two contiguous layers comprising ethylene-vinyl acetate copolymer, whenever obtained by the collapsed bubble process.
In the manufacture of pillow pouches with the thermoplastic material according to the present invention, any VFFS machine can be used which is equipped with an RF sealing equipment, such as for instance those commercially available from Thimmonier, or Sertic. In line of principle however any conventional VFFS machine can be adapted to the manufacture of RF-sealable pillow pouches by simply equipping it with a welding apparatus such as those commercially available from e.g. Colpitt, Cosmos, or Kiefel.
While the longitudinal seal can be obtained either by a conventional heat seal or by an RF seal, the transverse seal is always obtained by an RF seal. In the actual practice the RF seal is obtained by applying a pressure to the two film webs to be welded together, e.g. by means of a couple of bars, and welding the two webs together by RF at a frequency of about 27 MHz, which is the usual frequency provided in RF welding apparatuses. The temperature of the bars can be varied from about room temperature to as high as possible as long as the film does not stick thereto. In line of principle it would be preferable to have heated bars as this would shorten the welding time. While with PVC the bars are kept at about room temperature because PVC starts sticking at temperatures just above room temperature, with the thermoplastic films according to the present invention, having EVA outer layers, the temperature of said bars can suitably be increased up to 70-80xc2x0 C. The welding time isxe2x80x94as indicated abovexe2x80x94function of the temperature of the bars, but also of the pressure applied, of the thickness of the film, etc. Typically welding time of from about 0.5 to about 3 seconds can be used and pressure up to about 6 atm, preferably up to 5 atm. Optimal welding conditions can however be easily set by any skilled operator.
The film according to the present invention can however be employed in the manufacture of pillow pouches in any type of machine that can be used to this purpose.
A fourth object of the present invention is a method of packaging a flowable product in a pillow pouch using an RF weldable film characterized in that the RF weldable film is a multilayer thermoplastic film with an RF sealable outer layer of EVA containing from about 14 to about 28 wt. % VA and a PVDC layer. In a preferred embodiment of this method of packaging, the flowable product is packaged in a pillow pouch by means of a VFFS machine.
The invention will now be described with reference to the following examples which are intended to be illustrative of some preferred embodiments of thermoplastic films particularly suitable for the manufacture of pillow pouches for packaging of flowable products.
Said examples should not be interpreted as a limitation to the scope of the present Invention.
Melt Flow Indexes (MFI""s) are measured by ASTM D-1238, Condition E, 190xc2x0 C./2.16 kg, and are reported in grams/10 minutes.
The densities have been measured by ASTM D 792.
Melting points, if not otherwise indicated, have been determined by DSC following ASTM D-3418 (2nd heating xe2x88x9210xc2x0 C./min).
OTR is evaluated, at 23xc2x0 C. and 0% or 100% R.H., according to ASTM D-3985 using an OX-TRAN instrument by Mocon.
MVTR is measured by ASTM F-1249 using a Permatran W-1 Instrument =by Mocon.