Abstract: A system for determining the number of items within a stack of items, each item having a characteristic configuration, is provided. The system includes an image device attached to a moveable carriage, the imaging device being actuated to move to image the stack of items and a processing unit, coupled to the image device, for identifying the characteristic configuration of each of the stack of items from the scanned images.

Abstract: An instrument is provided with several sensing elements to enable several parameters of a processed yarn to be measured or determined. In order to minimize the total sensing element/guide contact with the yarn within the complete process threadline, the yarn is guided through the instrument by contact only with the inlet and outlet guiding elements of the instrument and contact operative sensing elements. One particular instrument consists, in succession, of an interlace sensing device, a tension sensing device and an oil content sensing device. The electrical resistance of the yarn is measured between two pins of the oil content sensing device and in this case, the first pin is also a tension sensing pin of the instrument, and the second pin of the oil content sensing device is also the outlet guide of the instrument.

Abstract: An apparatus that individualizes fibers within a feed stream without breaking the fibers. A first stage, having first pinch rollers, receives the feed stream and provides it to a second stage. The second stage receives the feed stream from the first stage, and provides a thinned stream to a third stage. Second stage apron belts draw the feed stream under tension from the first stage into the second stage. Second pinch rollers draw the feed stream under tension from the second stage apron belts and provide the thinned stream to the third stage. The third stage receives the thinned stream from the second stage and provides individualized fibers. Third stage apron belts draw the thinned stream under tension from the second stage into the third stage. Third pinch rollers draw the thinned stream under tension from the third stage apron belts and provide the individualized fibers.

Abstract: The invention relates to a process and to a device for the determination of the adhesion tendency of cotton by using cotton samples, whereby the sample taken from the material to be tested is opened down to the individual fiber as in the spinning process, and the fibers thus obtained are deposited on a testing surface under the influence of a certain centrifugal force in the form of a fiber ring. Following complete feeding of the sample, the deposited fiber ring is removed and the quantity of the fibers remaining caught on the testing surface is counted.

Abstract: A detection system for detecting the size of a print medium. A hollow tube is positioned adjacent the paper or print medium. An ultrasonic transducer apparatus launches pulses of ultrasonic energy into the tube, and is responsive to ultrasonic echoes of the pulses to convert echo pulse energy into electrical detected signals. A flag positioning apparatus selectively positions a blocking flag within the tube at a location spaced from the transducer apparatus which is indicative of a print medium size. A controller responds to the electrical detected signals to determine a print medium size. The flag positioning apparatus can provide a single flag movable along a longitudinal extent of the tube, or a set of flags spaced along the longitudinal extent, one or more of which are selectably deflected by the print medium.

Abstract: The invention concerns a measuring idler-roller for measuring stress distution of flexible bands that are moved in the direction of their length, in which roller force-measuring transducers arranged in recesses or their covers are surrounded by a plastic layer that fills in a gap and prevents the penetration of fine abraded metal particles, and makes easier the installation of the cover and/or the measuring transducer.

Abstract: An apparatus for detecting defects in a moving cast metal strip is provided that includes at least one Lamb-wave transducer housed inside a sensor wheel made of flexible material. The sensor wheel contains an acoustic coupling fluid and is designed to come into running contact with the surface of the product to be inspected. A runner is placed upstream of the sensor wheel for contact with the surface of the strip to be inspected. Upstream of the runner, a delivery system for delivering coupling fluid onto the surface of the moving product is provided, this fluid serving to wet the surface of the strip. The runner includes a roller having a contact width the same or greater than the width of the product for uniformly spreading the coupling fluid over the product. All of these components are installed in a movable carriage which is designed to run over the metal strip surface. The apparatus is capable of detecting defects in a steel strip moving at high speed.

Abstract: The device for on-line detection of structural faults in moving flat textile materials includes a spade-like leaf spring contact sensor (2) having a length of from 5 to 20 cm which is advantageously rounded and/or chamfered for engagement with threads in the flat textile materials; a mounting device (5) for mounting the spade-like leaf spring contact sensor (2) so that the contact sensor is at a positioning angle of 10 to 60.degree.

Abstract: Significant improvements in papermaking control can be achieved by employing an array of sensors that are positioned underneath the wire of the machine to measure the conductivity of the aqueous wet stock. The conductivity of the wet stock is directly proportional to the total water weight within the wet stock; consequently, the sensor provides information which can be used to monitor and control the quality of the paper sheet produced. Because CD water weight profile is obtained practically instantaneously, the MD and CD variations are essentially decoupled. Quality improvements to the sheet fabricated will be achieved by providing fast control of the actuators on the machine and by tuning components on the machine to eliminate the sources of variations.

Abstract: An apparatus and method for measuring the mass transport properties of pos materials. The apparatus is a permeation or diffusion cell that comprises two outer portions with longitudinal channels therein, two clamping plates with openings therein, two flow inlets and two flow outlets in fluid communication with such outer portion channels, which cell retains a sample of porous material during measurement procedures. In one embodiment, the apparatus is configured for measuring pure diffusion transport properties of the sample of porous material. In another embodiment, the apparatus is configured for measuring the diffusion and convection transport properties of the sample of porous material. In a further embodiment, the apparatus is configured for measuring the pure convection transport properties of the sample of porous material.

Abstract: Disclosed is a fiber testing apparatus which permits creep and strength testing of one or more fibers in a controlled environment, including a vacuum, at high temperatures. Components of the fiber tester provide for accurate measurement of the effects on the fiber(s) being tested when exposed to a chosen environment. The fiber tester includes a furnace system, fiber testing system, a fixed sample, a environmental control system, a mass flow control system, a Computer Data Acquisition and Control (CDAC) system, and a support system. Most of these systems are contained in a test chamber which is part of the environmental control system. These systems of the fiber tester allow various types of mechanical tests to be performed on one or more fibers under a variety of environmental conditions not previously achievable.

Abstract: The invention relates a method and a system for membrane thickness and the correspondent area distribution measurement based on the dependency of the acoustic intensity transmission coefficient upon the thickness of the insertion membrane and the proportion of the power of the transmitted acoustic plane waves to the area of the insertion membrane. The principle of the invention is that, when the acoustic wave travels in the acoustic medium and encounters an insertion membrane with different acoustic impedance, the intensity transmission coefficient T is related to the thickness d of the insertion membrane and the frequency f of the transmitting acoustic wave. As f sweeps, maximum T occurs at a set of frequency points corresponding to a certain thickness of the insertion membrane. By confining the sweeping frequency within a certain range, T.sub.max can only occur at one frequency point corresponding to a certain thickness of the insertion membrane.

Abstract: The device for the preparation of fibrous material to be tested comprises means for fastening said fibrous material, means for partitioning the fibrous material, and means for clamping and separating the fibrous material. The means for fastening, the means for partitioning and the means for clamping operate in essentially parallel surface planes. Since the device essentially operates by performing linear translations in surface planes, it is suited to automation, simple, maintenance-friendly and inexpensive.

Abstract: A system for determining the number of boards within a stack of boards, each board having a characteristic configuration, is provided. The system includes an imaging device attached to a moveable carriage, the imaging device being actuated to move to image the stack of boards and a processing unit, coupled to the imaging device, for identifying the characteristic configuration of each of the stack of boards from the scanned images.

Abstract: Significant improvements in papermaking control can be achieved by employing an array of sensors that are positioned underneath the wire of the machine to measure the conductivity of the aqueous wet stock. The conductivity of the wet stock is directly proportional to the total water weight within the wet stock; consequently, the sensor provides information which can be used to monitor and control the quality of the paper sheet produced. Because CD water weight profile is obtained practically instantaneously, the MD and CD variations are essentially decoupled. Quality improvements to the sheet fabricated will be achieved by providing fast control of the actuators on the machine and by tuning components on the machine to eliminate the sources of variations.

Abstract: Apparatus and method for non-destructively testing the stiffness of wood panels. The apparatus comprises a support framework having infeed, center and outfeed support assemblies mounted to the framework in spaced, successive positions. Each support assembly is adapted to contact the opposed panel surfaces of each panel to define a travel path along which the panel is advanced through the assembly. A first deflection member is provided intermediate the infeed and center support assemblies and is movable to contact one of the panel surfaces as each panel extends between the infeed and the center support assemblies. The first deflection member acts to bend the panel to a first pre-determined curvature. In a similar manner, there is a second deflection member intermediate the center and outfeed support assemblies movable to bend the panel to a second pre-determined curvature.

Abstract: A system is provided for the detection and control of a paper machine profile. The system is adapted to observe a physical characteristic of a moving, continuous paper web. For example, the system can observe a change in moisture content in the web, as represented by a "wet line". In response to observations of the physical characteristic, the system can also be adapted to adjust process controls and/or the physical composition of the web in an attempt to achieve a desired profile of the physical characteristic.

Abstract: To enable accurate yarn tension measurement by the elastic substrate in a yarn tension detecting apparatus including an elastic substrate 3, a yarn guide support 4 attached to the elastic substrate 3 approximately perpendicularly, a yarn guide 7 fixed at a free end of the yarn guide support 4, a strain measuring member 8 for measuring strain in the elastic substrate 3, and a resistor 9 that corrects effect of the temperature of the elastic substrate 3 from having a biased temperature distribution, a synthetic resin spacer 5 is interposed between the yarn guide 7 and the yarn guide support 4 and fixed thereto by a synthetic resin fixing member.

Abstract: A determination as to whether or not the absolute value PCHK of the deviation between a detection value PTANK of a pressure sensor and its average value PTANKAVE exceeds a predetermined pressure DLEAKCHK is repeated within a predetermined time TINTVAL. The number of times the absolute value PCHK has exceeded the predetermined pressure DLEAKCHK is measured on a failure determination counter C91BNG. When the value of the counter C91BNG exceeds a determination threshold value 91BJVD, it is determined that the pressure sensor fails (time t10).

Abstract: A method correlates average fiber diameter with performance for a complex filtration media comprising a matrix of fibers having a fibrillated component with a diameter so small (e.g., less than 0.01 microns), that cannot be physically measured with accuracy. The method manufactures a selected matrix, derives the number average diameter of the fibers according to prescribed steps, some of which do not require actual physical measurements, and observes a performance characteristic. The method repeats the foregoing steps for different matrixes, yielding different number average diameters. The method expresses change in the selected performance characteristic as a function of change in number average diameter of the matrices.

Abstract: The apparatus for determining the stiffness of sheet material is provided with mechanical means which periodically touch the sheet material, causing it to vibrate. The sounds produced by the vibration are detected by a detector. From the detected sounds an evaluating device determines the stiffness of the sheet material. The sheet material is held or guided in a transport device such that it can yield to the mechanical action within certain limits in the area of contact without being irreversibly deformed.

Abstract: While the three-flat method is used as background art, a technique for analyzing the difference between two planes by approximating it with symmetry power series polynomials are employed, and measurement is effected at two positions where the reference surface and the sample surface are in a predetermined reference rotation state and where they are rotated from each other by 90 degrees from the former state; whereby the approximate surface form of the whole plane can be determined by a very simple arithmetic operation with a high accuracy. Of three glass sheets, different pairs of two glass sheets 53 and 54 are successively selected three times. The difference between two surfaces to be measured in each pair of the two glass sheets 53 and 54 is measured at a first position where, with respect to one glass sheet 53, the other is set at a predetermined rotational position; and a second position where the two sheets are rotated from each other by 90 degrees from the first position.

Abstract: An apparatus and method for obtaining fiber weight measurements in the wet end of a sheetmaking system and for verifying fiber weight measurements taken in the wet end of a sheetmaking system which includes a water weight sensor positioned beneath the wire in the wet end of the sheetmaking system for obtaining water weight measurements and load cells residing beneath the water weight sensor for weighing the wet end sensor and the wire with wetstock (total weight) and without wetstock (tare weight). In one embodiment, the water weight measurement and the tare weight measurement are subtracted from the total weight to obtain the fiber weight in the wetstock. In another embodiment, the water weight measurement is used to obtain an predicted fiber weight measurement and the determined fiber weight is used to verify the predicted fiber weight measurement and the accuracy of the water weight measurement device.

Abstract: Measuring the limpness of a note is necessary to separate a worn note out of circulation. Several methods are disclosed which can be used either alone or in combination to test for limpness. One method measures the note's ability to reflect light or transmit the light. Another method measures the response of the note to an acoustic wave. Another method measures the note's deflection to a pressure or force. Yet another method measures the dielectric value of the note when placed between the plates of a capacitor. A final method involves measuring the thermal conductivity of the note. In each case, a limp note will produce distinguishable results from a stiff note.

Abstract: For determination of the forces arising at a feeding means in an injection molding machine for plastic materials, a first static sensor is provided for determining at least the forces arising during the material preparation stage. A further force sensor detects in essence the forces arising during injection and, as soon as the first measured value reaches a limit value F1, the first static sensor passes on the further detection of the forces to the further sensor, wherein the limit value F1 at the same time serves as calibration value for the further sensor.

Abstract: The invention is a device for representing changes in barometric pressure comprising an electronic barometric pressure sensor 2 and a digital differentiating circuit in which a differential quotient .DELTA.P/.DELTA.t is found which is connected to a display of the speed of the change in barometric pressure with mathematical sign and numerical figure. The electrical supply for said barometric pressure sensor 2 is obtained in cyclical intervals. The cyclically determined measured barometric pressure values are checked for plausibility, only the plausible measured barometric pressure values being used to find the differential quotient .DELTA.P/.DELTA.t.

Abstract: A system for authenticating bank notes by checking for raised print (37) produced by an intaglio printing process which only occurs on genuine bank notes. Each note (36) is individually transported past a pair of brushes (38) whose bristles are in contact with the two faces of the note. Microphones (28) are placed in close proximity to the brush means to sense the noise from the brush means which increases when there is raised print. Output from the microphones are digitized and applied to a data processing means (22) which determines whether the note contains raised printing, and hence whether the note is genuine or not, by generating a value based on the digitized outputs of the microphones (28) and comparing this value with stored values.

Abstract: A temperature compensation method for a microprocessor based electro-pneumatic converter device including an initial calibration sequence, a compensation sequence, and an operation sequence. Linearization of an electro-pneumatic positioner including the steps of adjusting the positioner feedback linkage until a predetermined reference position is attained, reading a position feedback value and determining the required feedback linearization value to achieve a linear relationship between the output/input. A calibration method and a configuration method independent of calibration for a microprocessor based electro-pneumatic converter device including an initial calibration sequence, a configuration sequence, and an operation sequence.

Abstract: An automatic measuring apparatus is capable of measuring the thickness of a work piece with a high degree of precision. Distance data for carriers is removed from distance data representative of the distances between a pair of surface plates which are detected in a non-contact manner. An eddy current sensor mounted on a first surface plate detects a distance therefrom to a second surface plate and generates a corresponding analog voltage signal. When the eddy current sensor enters and exits a space between two adjacent carriers, voltage signals are generated. The voltage signals are processed to determine the voltage value of a digital voltage signal that has a maximum frequency or a maximum number of occurrences among the voltage signals being processed. The resultant determination is used to arrive at the work piece thickness.

Abstract: The invention relates to a test apparatus (1) with an end face (11) in front of which a yarn, roving or sliver is moved along in the longitudinal direction in order to test properties, with a plurality of zones of action (8, 9, 10) for producing a respective interaction between the test apparatus and the test material. In order to be able to provide a simple path, which is independent of the number of zones of action, for the yarn, roving or sliver, the yarn, roving or sliver is guided at least approximately in one plane transverse to the end face.

Abstract: Apparatus and method for detecting the presence of a splice in a running length of web material, particularly photosensitive web material. The apparatus includes first and second encoders coupled to first and second rollers, respectively. As the web material is transported across the rollers, the speeds of the rollers are continuously and simultaneously detected. The rollers will travel at substantially the same speed when the web is being transported across both rollers. The presence of the splice is detected when the speeds of the two rollers differ.

Abstract: Measuring the limpness of a note is necessary to separate a worn note out of circulation. Several methods are disclosed which can be used either alone or in combination to test for limpness. One method measures the note's ability to reflect light or transmit the light. Another method measures the response of the note to an acoustic wave. Another method measures the note's deflection to a pressure or force. Yet another method measures the dielectric value of the note when placed between the plates of a capacitor. A final method involves measuring the thermal conductivity of the note. In each case, a limp note will produce distinguishable results from a stiff note.

Abstract: Method for operating a traversing sensor apparatus, wherein the properties of a paper web are measured through traversing such that a measuring head is moved during the measurement in the cross-machine direction. The movement of the measuring head in the cross-machine direction is stopped above the paper web and data is collected for a certain period through measurement from an area narrower than the width of the paper web, whereafter the movement of the measuring head in the cross-machine direction is continued. The data collected from an area narrower than the width of the paper web is used to calculate MD and CD values and to determine the effect of harmonic variations.

Abstract: In this invention there is disclosed a system and method for predicting web breaks in a paper machine. In particular, this invention uses a neural network to predict web break tendencies from sensor measurements taken from the paper machine. Also, an induction tree model is used to isolate the root cause of the predicted web break tendencies.

Abstract: Measuring the limpness of a note is necessary to separate a worn note out of circulation. Several methods are disclosed which can be used either alone or in combination to test for limpness. One method measures the note's ability to reflect light or transmit the light. Another method measures the response of the note to an acoustic wave. Another method measures the note's deflection to a pressure or force. Yet another method measures the dielectric value of the note when placed between the plates of a capacitor. A final method involves measuring the thermal conductivity of the note. In each case, a limp note will produce distinguishable results from a stiff note.

Abstract: A sensor system for measuring physical properties of a sheet. In one embodiment, the sensor system measures paper curl and thickness using two sensors, each of which includes a member, a base, and measurement circuit. The two members are positioned in opposition to each other and both contact the sheet as it passes between them. Each member is coupled to a base, which includes a measurement circuit. Each measurement circuit measures the displacement of its associated member. In another embodiment, the sensor system measures stiffness and curl using two pairs of opposed sensors. In yet another embodiment, the sensor system measures thermal diffusivity of a sheet of paper using three sensors, one of which includes a heater for heating the sheet of paper and the other two sensors include thermocouples in contact with the sheet of paper for sensing the heat of the paper.

Abstract: An apparatus (200) and method are provided for testing a nozzle of a pick-and-place system (100). The apparatus (200) includes a reservoir (206) configured to carry a fluid, a membrane (204) covering an opening of the reservoir (206), and a reservoir pressure sensor. The apparatus may further include a processor (118) coupled to the reservoir pressure sensor (208) and an output device (116) coupled to the processor (118). The nozzle (104) is positioned to contact and displace the membrane (204), thus changing the pressure of the fluid within the reservoir (206). The reservoir pressure sensor (208) senses pressure changes within the reservoir (206) and generates a signal that varies in response to the displacement of the membrane. The signal is compared to a predetermined signal to detect whether the nozzle has the proper position, the proper alignment, sufficient vacuum, and other errors affecting pick-and-place systems.

Abstract: Measuring the limpness of a note is necessary to separate a worn note out of circulation. Several methods are disclosed which can be used either alone or in combination to test for limpness. One method measures the note's ability to reflect light or transmit the light. Another method measures the response of the note to an acoustic wave. Another method measures the note's deflection to a pressure or force. Yet another method measures the dielectric value of the note when placed between the plates of a capacitor. A final method involves measuring the thermal conductivity of the note. In each case, a limp note will produce distinguishable results from a stiff note.

Abstract: An ultrasonic material constant measuring system comprising a reference unit, an examination unit, at least a case equipped in at least the examination unit, and a signal processing unit. The reference unit consists of at least an input ultrasonic transducer T.sub.o and at least an output ultrasonic transducer R.sub.o. The examination unit consists of at least an input ultrasonic transducer T.sub.s and at least an output ultrasonic transducer R.sub.s. The case is placed between the ultrasonic transducers T.sub.s and R.sub.s. The signal processing unit is connected with output terminals of the ultrasonic transducers R.sub.o and R.sub.s. When electric signals are applied to the ultrasonic transducers T.sub.o and T.sub.s, ultrasounds are emitted in air from the ultrasonic transducers T.sub.o and T.sub.s, respectively, and then received by the ultrasonic transducers R.sub.o and R.sub.s, respectively. If at least a sheet of paper is placed in case 1, the ultrasound emitted from ultrasonic transducer T.sub.

Abstract: A thermal print head has thermal print elements located along an edge of a substrate between two faces thereof. An impression roller resiliently urges a print receiving medium, for example a mail item in a postage meter, into ink transfer engagement with an ink layer of a thermal transfer ink ribbon and urges the ink ribbon into heat transfer engagement with the thermal print elements. The print head is mounted to be adjustable as to location of the line of print elements relative to the impression roller and the angular disposition of the print head. The resiliently pressure exerted by the impression is adjustable. Adjustment of the print head and of the pressure may be effected automatically in response to sensing of compressibility of the print receiving medium.

Abstract: Method of detecting yarn unevenness appearing as periodic variations of a spun yarn. First, plural yarn samples are taken. Then, k distinct spectrograms are obtained according to the number of the samples. These k spectrums are averaged to create an overall spectrogram. The height of adjacent channels in the overall spectrogram are averaged to create a reference spectrogram. Either the overall spectrogram of the distinct spectrograms are compared with the reference spectrogram of find those portions of the channels that exceed the reference spectrograms in height. These exceeding portions are displayed. Therefore, realistic defective added nonuniformities contained in the spun yarn can be easily detected.

Abstract: The present invention relates to a compression test device for a paper strip, including means for laterally holding the strip to limit its buckling during the testing. The lateral holding means include a tube in which the strip is freely rolled with more than one turn.

Abstract: A digital compensation circuit for calibrating a sensor is described. The compensator circuit includes a serial communication circuit for receiving data relating to a plurality of parameters and a compensation circuit coupled to serial communication circuit for providing piece-wise linear compensation of a temperature coefficient (TC). In one embodiment, the compensation circuit further includes a detector for detecting a threshold for a digital temperature and providing an output and a plurality of registers coupled to the detector and the serial communication circuit, a first plurality of registers for providing a first value if the digital temperature is above the threshold, a second of the plurality of registers for providing a second value if the digital temperature is below the threshold.

Abstract: The invention relates to a method and an equipment for defining the cross-directional properties of a sheet in a continuous sheet making process. According to the invention, the set point profile of the actuators affecting the cross-directional properties of the sheet is defined, high frequencies are filtered from the defined profile, and shrinkage nonlinearity is deduced from the filtered profile without modulating or stimulating the actuators.

Abstract: The apparatus for testing the characteristics of waterproofness and breathability of fabrics includes a demonstration unit, a base unit, and a fluid conduit and valve. The demonstration unit has a transparent wall and a support plate/gasket combination to retain and support the test fabric specimen. The flexible fluid conduit runs between the demonstration unit and the base unit, and a valve is positioned in the conduit. To test a fabric's waterproofness: the demonstration unit is assembled; the base unit is filled with water; the demonstration unit is placed lower than the base unit, and thus, water flows into the demonstration unit; and the demonstration unit is positioned to expose and view the fabric.

Abstract: The invention relates to a thickness gauge (1) for non metallic materials (4) in the form of foil, film, tape or the like which comprises first non contact measuring means (3), designed to measure the distance of the faced material surface, and second non contact measuring means (5), designed to measure the distance of a metal reference surface (6), said first and second measuring means (3, 5) being installed on one side of a space for receiving the material (4) and operating in two coaxial spatial regions, so that their measurements refer to a same measuring axis (8), wherein the first non contact measuring means (3) is a backscattering fluid sensor.

Abstract: A EMAT inspection system is utiliized on sheet metal prior to it being formed or rolled to identify surface defects and sub-surface defects such as pencil pipe inclusions by using ultrasonic Lamb waves with the results being displayed on a remote screen of a display and control system which also records the inspection results and controls the EMAT system.

Abstract: A technique and apparatus for evaluating the degree of hydroenhancement achieved in a woven fabric. The degree of hydroenhancement is related to the permeability of the woven fabric (i.e., the permeability of the woven fabric will decrease as the hydroenhancement increases). The hydroenhanced fabric is pulled over a vacuum source (while a constant vacuum is maintained) and the air flow through the fabric is measured. The air flow per unit area of fabric is then calculated and defined as the permeability. Alternatively, the permeability can be calculated by maintaining a constant air flow and measuring the vacuum drop associated with the treated fabric. The degree of hydroenhancement may then be assessed as related to this permeability measurement.

Abstract: This invention relates to improved sheet products and specifically to improved nonwoven sheet products made from highly oriented plexifilamentary film-fibril webs. The improved sheet products have high opacity and strength with a much wider range of porosity or Gurley Hill Porosity Values. In particular, sheet products made in accordance with the present invention have considerably higher Gurley Hill Porosity Values than similar weight sheet products subject to the same finishing treatments in accordance with prior known sheet materials. Similarly, sheet products made in accordance with the present invention can be made which have much lower Gurley Hill Porosity Values than prior sheet materials. The invention includes numerous methods and data characterizing the webs and sheets that form the improved sheet materials.

Abstract: Material samples may be tested for weathering by a method which comprises securing the samples to a rack which rotates about a central radiation source, and exposing the samples to irradiation from the source at a first intensity of at least about 1.5 SUNS, while rotating the rack at a rate of at least about 6 rpm. Alternatively, a lower radiation intensity may be provided from the same apparatus, using a lower rotation rate. The method may also comprise a step of varying the inductance of a circuit supplying power to the central radiation source as one changes the intensity of the irradiation, to enhance the constancy of spectral distribution of the irradiation at the different intensities.