Abstract: Example systems, devices, and methods are described for evaluating the relative leak safety of threaded connections in well tubulars. The method includes evaluating leak risk using a quadratic leak criterion, which is a function of the effective pressure (Pe) and includes three constants: a first constant called the leak path factor (?), a thread modulus (?), and a makeup leak resistance (?). The method in some implementations includes identifying at least three test cases with different ?p expected to leak under certain conditions. The method includes fitting a quadratic expression to a subset of values associated with the leaking test cases, in which the resulting quadratic expression includes values for the three constants.

Abstract: Example systems, devices, and methods are described for evaluating the relative leak safety of threaded connections in well tubulars. The method includes evaluating leak risk using a quadratic leak criterion, which is a function of the effective pressure (Pe) and includes three constants: a first constant called the leak path factor (?), a thread modulus (?), and a makeup leak resistance (?). The method in some implementations includes identifying at least three test cases with different ?p expected to leak under certain conditions. The method includes fitting a quadratic expression to a subset of values associated with the leaking test cases, in which the resulting quadratic expression includes values for the three constants.

Abstract: Described are systems and methods for evaluating the leak safety of threaded connections in well tubulars. A method, for example, includes assessing leak risk according to a Leak Criterion with Thread Shear. The Leak Criterion with Thread Shear is a function of the conditions relative to a pin-box interface radius and includes two constants: a Thread Modulus (alpha) and a Makeup Leak Resistance (beta). The leak risk is evaluated at the pin-box interface and is a function of differential pressure, effective stress, and shear stress. Lab tests conducted under known conditions are described for calculating the constants, alpha and beta, which are independent of extrinsic states or conditions.

Abstract: A triaxial connection leak criterion for assessing and optimizing threaded connections in well tubulars, together with an associated leak safety factor for use in tubular design, is described. The triaxial leak criterion introduces the dependence of leak on hydrostatic pressure and on two constants associated with the connection: a Thread Modulus and a Makeup Leak Resistance. These two constants represent inherent properties of a particular threaded connection, independent of external conditions. Simple lab tests are described for determining the two connection constants, without expensive qualification testing or finite-element analysis. Graphical tools based on the triaxial leak criterion include a leak line and a leak circle for visually assessing the leak risk associated with any of a variety of load cases.

Abstract: Titanium coordination complexes, particularly titanium catecholate complexes, can be attractive active materials for use in flow batteries. However, such coordination complexes can be difficult to prepare from inexpensive starting materials, particularly in aqueous solutions. Titanium oxychloride and titanium tetrachloride represent relatively inexpensive titanium sources that can be used for preparing such coordination complexes. Methods for preparing titanium catecholate complexes can include combining one or more catecholate ligands and titanium oxychloride in an aqueous solution, and reacting the one or more catecholate ligands with the titanium oxychloride in the aqueous solution to form the titanium catecholate complex. Titanium tetrachloride can be used as a precursor for forming the titanium oxychloride in situ. In some instances, the titanium catecholate complex can be isolated in a solid form, which can be substantially free of alkali metal ions.

Abstract: Titanium coordination complexes, particularly titanium catecholate complexes, can be attractive active materials for use in flow batteries. However, such coordination complexes can be difficult to prepare from inexpensive starting materials, particularly in aqueous solutions. Titanium oxychloride and titanium tetrachloride represent relatively inexpensive titanium sources that can be used for preparing such coordination complexes. Methods for preparing titanium catecholate complexes can include combining one or more catecholate ligands and titanium oxychloride in an aqueous solution, and reacting the one or more catecholate ligands with the titanium oxychloride in the aqueous solution to form the titanium catecholate complex. Titanium tetrachloride can be used as a precursor for forming the titanium oxychloride in situ. In some instances, the titanium catecholate complex can be isolated in a solid form, which can be substantially free of alkali metal ions.

Abstract: A forward converter incorporating a low loss snubber and transformer reset circuit is disclosed. The transformer core of the forward converter is reset by the exchange of magnetizing energy between the transformer secondary winding and an appropriately sized capacitor of the reset circuit during the off period of the power switch. The exchange of magnetizing energy from the capacitor to the transformer secondary winding is independent of power switch operation.

Abstract: A method for adjusting the leakage current of insulated gate field effect transistors comprised of silicon mesas epitaxially formed on a sapphire substrate, wherein the leakage current of a P channel transistor is increased by preoxidizing the silicon prior to standard processing and/or wherein the leakage current is decreased by annealing the silicon in a reducing atmosphere in addition to standard processing steps. The leakage current of an N channel transistor is reduced by preoxidizing the silicon of the transistor prior to forming the transistor and/or is increased by annealing in a reducing atmosphere in addition to the steps necessary for forming the transistor.

Abstract: Capacitance is measured using a conventional meter while a DC bias voltage in a range from 0 to 10K volts is applied across the capacitance under test. An LC series resonant circuit is disposed between the capacitance under test and one input of the capacitance meter to provide a low impedance path for the 1 MHz test signal produced by the capacitance meter. P-I-N diodes are disposed across the input terminals of the capacitance meter to shunt the discharged energy from the resonant circuit capacitance should the capacitor under test short circuit. A resistance is in series with the resonant circuit to provide a voltage divider to lower the voltage appearing across the capacitance-meter input terminals to a value below the damage-threshold voltage level of the capacitance-meter.