摘要:
A method and apparatus for positioning and supporting the work platform of a mobile workover rig is disclosed. The work platform of the preferred embodiment of the present invention utilizes a unique support structure and automated positioning system for positioning the work platform at the desired height above the wellhead equipment. The preferred embodiment of the present invention utilizes a specialized automated “pinning” system that secures the work platform at the desired height. Additionally, the present invention utilizes one or more support cylinders to position and support the work platform in the horizontal position over the wellhead equipment. The automated positioning and pinning system of the present invention is a unique system that significantly reduces the time required to position the work platform of a mobile workover rig in the operating position, as well as significantly reduces the risk of injury to rig personnel assisting in the positioning operations.
摘要:
The invention relates to alcohol-modified glycidyl carbamate resins wherein at least some of the glycidol groups in the resin have been replaced with an alcohol. The invention also relates to coating compositions containing the resins.
摘要:
One embodiment described herein provides a circuit to approximate the inductor current of a power supply that includes a capacitor; charge/discharge circuitry configured to charge the capacitor with a voltage that is proportional to an input voltage rail of the power supply, and discharge the capacitor with a voltage that is proportional to the output voltage of the power supply; and error correction circuitry is configured to adjust the voltage that is proportional to the input voltage rail and the voltage that is proportional to the output voltage based on an instantaneous current of the inductor; and wherein the voltage on the capacitor is proportional to a current associated with the inductor.
摘要:
This document discusses, among other things, a regulator circuit. The regulator circuit can controllably connect a first voltage to an inductor using a first switch and can controllably connect a second voltage to the inductor using a second switch. The first switch can be turned off and the second switch can be turned on for a duration proportional to a difference between the first voltage and a third voltage, divided by the first voltage. The first switch can be turned off and the second switch can be turned on for a duration proportional to the third voltage divided by the first voltage. One of the first or third voltages can correspond to a desired output voltage.
摘要:
In one aspect, the invention is directed to polypeptides having an amylase activity, polynucleotides encoding the polypeptides, and methods for making and using these polynucleotides and polypeptides. The polypeptides of the invention can be used as amylases to catalyze the hydrolysis of starch into sugars.
摘要:
An information-processing method for application-specific processing of messages. A message is received. Whether the message is in a selected application format is ascertained. If not, the message is routed to a next location. If so, the message is routed to a selected application processor, processed by the processor, and routed to the next location.
摘要:
The present invention includes a pass transistor that limits current drawn from a circuit without using a series resistor and while drawing minimal current from an external supply. A current mirror of the output current is formed and compared to a reference current. When the output current increases, the mirror current increases proportionally, and when a threshold is crossed, the pass transistor is turned off. The pass transistor is biased from a charge pump that provides a voltage, a current from which a current mirror is drawn that controls the pass transistor.
摘要:
This invention relates to polyurethane elastomers and to a process for their production. These elastomers comprise the reaction product of a (cyclo)aliphatic isocyanate component having an NCO group content of about 20 to about 45%, with an isocyanate-reactive component comprising one or more low unsaturation polyether polyols, a low molecular weight organic compound containing two hydroxyl groups and which is free of amine groups, and, optionally, one or more organic compounds having a molecular weight of about 200 to about 500, a hydroxyl functionality of 3 to 4 and comprising an amine-initiated polyether polyol.
摘要:
The present invention is directed to polyisocyanate addition compounds which i) are substantially free from isocyanate groups and are prepared from one or more a)polyisocyanate adducts containing isocyanurate, uretdione, biuret, allophanate, iminooxadiazine dione carbodiimide and/or oxadiazinetrione groups and/or b) NCO prepolymers, ii) contain urethane groups, iii) contain siloxane groups (calculated as SiO, MW 44) in an amount of 0.002 to 50% by weight, and iv) contain ethylenically unsaturated groups (calculated as C═C, MW 24) in an amount of 2 to 40% by weight, wherein the preceding percentages are based on the solids content of the polyisocyanate addition compounds and wherein the siloxane groups are incorporated by reacting an isocyanate group with a compound containing one or more hydroxyl groups directly attached to a carbon atom and one or more siloxane groups to form urethane groups and optionally allophanate groups, provided that more than 50 mole % of the groups that chemically incorporate siloxane groups into the polyisocyanate addition compounds are urethane groups. The present invention also relates to the use of the polyisocyanate addition compounds in coating compositions curable by free radical polymerization.
摘要:
The present invention is directed to a polyisocyanate mixture i) having a monomeric diisocyanate content of less than 3% by weight, ii) having a urethane group content of more than 50 equivalent %, based on the total equivalents of urethane and allophanate groups, and iii) containing siloxane groups (calculated as SiO, MW 44) in an amount of 0.002 to 50% by weight, wherein the preceding percentages are based on the solids content of the polyisocyanate mixture and wherein the siloxane groups are incorporated by reacting a) an isocyanate group from a polyisocyanate adduct containing at least 60% by weight, based on the total weight of the polyisocyanate adduct, of a polyisocyanate adduct which is prepared from 1,6-hexamethylene diisocyanate, contains isocyanurate, iminooxadiazine dione and/or uretdione groups and has a viscosity at 25° C. and 100% solids of less than 2000 mPa·s, with b) a compound containing one or more hydroxyl groups directly attached to a carbon atom and one or more siloxane groups to form urethane groups. The present invention also relates to the use of this polyisocyanate mixture, optionally in blocked form, as an isocyanate component in two-component coating compositions.