Abstract: A collapsible bag (2) for the storage and transport of bulk materials comprises a bottom panel (13), a plurality of side panels (11, 12), and a pair of substantially parallel tubular guide members (4). The guide members (4) are secured on or adjacent to the tops of at least some of the side panels (11, 12). The tubular members (4) are resilient and connected together by rigid spacing means (22) at or adjacent to their ends. The invention also provides a method for manufacturing the bag and a device for modifying a conventional bag to make a bag in accordance with the invention.

Abstract: A call progress monitor circuit is disclosed for a digital DAA in which digital information is transmitted across an isolation barrier from phone line side circuitry to powered side circuitry. In particular, the call progress monitor circuit of the present invention converts oversampled digital transmit and receive data into analog transmit and receive signals and then combines them to produce a call progress signal that is provided to be fed to a speaker driver circuit. In addition, the call progress signal in one embodiment is filtered with a low pass filter. The call progress monitor circuit in one embodiment includes oversampled digital-to-analog converters, a summing circuit, and a low pass filter. Corresponding methods for monitoring the progress of a call utilizing oversampled digital transmit and receive signals are also disclosed.

Abstract: Polymers are derivatized and then may be introduced into a wellbore, such as in a hydraulic fracturing treatment. A polymer may be a guar powder that is mixed with a organic solvent and derivatized using a derivatizing agent, such as sodium chloroacetate. The polymer is typically derivatized in bulk prior to introduction into the wellbore. The derivatized polymer may be hydrated and/or crosslinked prior to introduction into the wellbore.

Abstract: An isolation system is provided that is suitable for use in telephony, medical instrumentation, industrial process control and other applications. Preferred embodiments of the invention comprise a capacitive isolation barrier across which a digital signal is communicated. The system provides a means of communication across the isolation barrier that is highly immune to amplitude and phase noise interference. Clock recovery circuitry may be employed on one side of the isolation barrier to extract timing information from the digital signal communicated across the barrier, and to filter the effects of phase noise introduced at the barrier. Delta-sigma converters may be disposed on both sides of the isolation barrier to convert signals between analog and digital domains. An isolated power supply may also be provided on the isolated side of the barrier, whereby direct current is generated in response to the digital data received across the isolation barrier.

Abstract: This invention concerns a process to provide high purity akylene carbonate though use of multiple distillations wherein the unused fractions are recycled to the reactor.

Abstract: This invention concerns a process to provide high purity alkylene carbonate though use of multiple distillations wherein the unused fractions are recycled to the reactor. The high purity alkylene carbonate may be further purified by use of carbon to produce electrochromic or photochromic grade alkylene carbonate by reducing its UV absorbance.

Abstract: An isolation system is provided that is suitable for use in telephony, medical instrumentation, industrial process control and other applications. Preferred embodiments of the invention comprise a capacitive isolation barrier across which a digital signal is communicated. The system provides a means of communication across the isolation barrier that is highly immune to amplitude and phase noise interference. Clock recovery circuitry may be employed on one side of the isolation barrier to extract timing information from the digital signal communicated across the barrier, and to filter the effects of phase noise introduced at the barrier. Delta-sigma converters may be disposed on both sides of the isolation barrier to convert signals between analog and digital domains. An isolated power supply may also be provided on the isolated side of the barrier, whereby direct current is generated in response to the digital data received across the isolation barrier.

Abstract: Disclosed is a composition useful as a mold release agent, exhibiting viscosities, lubricities and melting points which cover a wide range and fit a variety of types of molding equipment, comprising: a) 5 to 40% by weight one or more water soluble copolymers of ethylene oxide and propylene oxide which are in liquid phase at ambient temperatures; b) 15 to 60% by weight a crystalline polyoxyalkylene having a melting point slightly above ambient; and c) 100 to 5000 ppm of one or more antioxidant additives.

Abstract: A programmable gain preamplifier is provided which has a low temperature drift and good dynamic range characteristics. The programmable gain preamplifier may be coupled to an analog to digital converter. The analog to digital converter may be a switched capacitor array analog to digital converter. The analog to digital converter may be a resistor array and capacitor array analog to digital converter. A resistor string having contacts out of the resistor string current path may be utilized with the programmable gain preamplifier or the analog to digital converter or both. The resistor string may be utilized to calibrate the analog to digital converter or the programmable gain preamplifier or both. The resistor string may also be utilized by the analog to digital converter when conversions are being performed. The programmable gain preamplifier provides a programmable gain of the difference between two input signals (Ain and Ain′ for example).

Abstract: This invention concerns a composition useful as a paint remover, comprising: alkylene carbonate such as propylene carbonate or ethylene carbonate, hydrogen peroxide, and water, and optionally an alcohol such as benzyl alcohol. In another broad respect, this invention concerns a process for removing paint, comprising: applying a composition containing alkylene carbonate, hydrogen peroxide, and water to a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint. In another broad respect, this invention is a composition useful as a paint remover, comprising: dialkyl carbonate, hydrogen peroxide, and water, optionally containing an alcohol, optionally containing a glycol ether. In another broad respect, this invention is a process for removing paint, comprising: applying a composition containing dialkyl carbonate, hydrogen peroxide, and water to a painted surface for a time and under conditions effective to cause blistering or bubbling of the paint.

Abstract: An antenna structure and associated method are disclosed that provides a lightweight and reduced-cost antenna element. The antenna structure may include a printed circuit board material coupled to a support structure. The printed circuit board may include electrical circuitry patterns and may have components mounted thereon to provide desired transmit and receive functionality, for example, to provide radio frequency transmit/receive functionality along with phase shifter and control circuitry. The support structure may be a light-weight material, for example, a space-qualified foam material that is strong and light-weight. The combined antenna structure of the present invention may thereby form a strong, rigid and light-weight antenna structure that may be used as sub-array elements in an antenna array, such as an ESA system.

Abstract: Methods and compositions useful for hydraulic fracturing of subterranean formations that utilize relatively lightweight and/or substantially neutrally buoyant particles as particulate proppant material.