One-step solution combustion synthesis (SCS) methods for fabricating durable crystalline transuranic-doped rare earth zirconium pyrochlores are described. Methods are fast, amenable to upscaling, and present a simple strategy for producing crystalline ceramic materials that meet the minimum attractiveness criteria for special nuclear material. The methods include analysis of reactants and reaction conditions to select proper fuel as well as proper fuel content so as to encourage formation of the crystalline product in a single-step synthesis procedure.

A slope ?.sup.t1.sub.HC in a linear area of sensor output characteristics for a mixed atmosphere of CO and THC and a slope ?.sup.t1.sub.NH in the linear area of the sensor output characteristics for NH.sub.3 are specified in advance at a time when a time t1 has elapsed since a start of use of an engine. In performing calibration of an NH.sub.3 sensor when a time t2 (greater than the time t1) has elapsed, a slope ?.sup.t2.sub.HC in the linear area of the sensor output characteristics for the mixed atmosphere is specified, a value ?.sup.t2.sub.NH is calculated from an equation ?.sup.t2.sub.NH=?.sup.t2.sub.HC/(?.sup.t1.sub.HC/?.sup.t1.sub.NH), and the calculated value ?.sup.t2.sub.NH is determined as a new slope in the linear area of the sensor output characteristics for an NH.sub.3 gas.

Bimetallic oxidation catalyst devices include a support body, one or more metal A bulk deposits disposed on the support body, and a plurality of metal B atomic clusters disposed on the surface of each of the metal A bulk deposits. Metal A and metal B are different metals each selected from the group consisting of platinum group metals (PGM), Ag, Au, Ni, Co, and Cu, and substantially no metal B is deposited on the support body. At least 85% by weight of the metal B atomic clusters comprise up to 10 atoms and the maximum metal B atomic cluster size is 200 metal B atoms. The combined loading of metal A and metal B can be less than 1.5% by weight relative to the weight of the support body. Metal A can include Pd, Rh, Rh, or Pd, and metal B can include Pt, Pt, Ag, or Ag.

Described herein is a method for detecting steady state ammonia slip for a motor vehicle having an internal combustion engine and an emissions control system. The emissions control system includes a selective catalytic reduction (SCR) device, a NOx sensor, and a controller. The controller executes a method for ammonia slip detection that includes determining if the SCR device is at steady state, comparing a NOx measurement from the NOx sensor with a predicted NOx value. If the NOx measurement exceeds the predicted NOx value by a threshold, perturbing a reductant injection, the perturbation having a selected magnitude and a selected duration. The method also includes measuring a NOx value resulting from the perturbation and computing a gradient thereof relative to the measured NOx, and ascertaining if a gradient of the NOx resulting from the perturbation exceeds a threshold and identifying a reductant slip condition if so.

The invention relates to a gas purifier that removes moisture and oxygen from inert gases and reducing gases, for example, at sub-atmospheric pressures. The purifier can remove part per million levels of moisture in a gas stream to less than 100 parts per trillion by volume, and has a low pressure drop and a sharp breakthrough curve.

Described herein is a method for detecting steady state ammonia slip for a motor vehicle having an internal combustion engine and an emissions control system. The emissions control system includes a selective catalytic reduction (SCR) device, a NOx sensor, and a controller. The controller executes a method for ammonia slip detection that includes determining if the SCR device is at steady state, comparing a NOx measurement from the NOx sensor with a predicted NOx value. If the NOx measurement exceeds the predicted NOx value by a threshold, perturbing a reductant injection, the perturbation having a selected magnitude and a selected duration. The method also includes measuring a NOx value resulting from the perturbation and computing a gradient thereof relative to the measured NOx, and ascertaining if a gradient of the NOx resulting from the perturbation exceeds a threshold and identifying a reductant slip condition if so.

For the purification of waste gas containing carbon compounds and nitrogen oxides by means of a regenerative post-combustion system, at least two regenerators (A, B, C) filled with heat accumulator bodies (7a, 7b, 7c) and connected by a combustion chamber (10) are provided, wherein the waste gas is alternately heated in a regenerator (A, B, C), the carbon compounds are oxidised in the combustion chamber (10), and, with the addition of a nitrogen-hydrogen compound, the nitrogen oxides are reduced in the combustion chamber (10) thermally and thus not catalytically. Remaining nitrogen oxides are removed by means of a catalytically active heat accumulator layer (6a, 6b, 6c) and the addition of a further nitrogen-hydrogen compound in the regenerator (A, B, C) from which the clean gas exits.

A slope ?.sup.t1.sub.HC in a linear area of sensor output characteristics for a mixed atmosphere of CO and THC and a slope ?.sup.t1.sub.NH in the linear area of the sensor output characteristics for NH.sub.3 are specified in advance at a time when a time t1 has elapsed since a start of use of an engine. In performing calibration of an NH.sub.3 sensor when a time t2 (greater than the time t1) has elapsed, a slope ?.sup.t2.sub.HC in the linear area of the sensor output characteristics for the mixed atmosphere is specified, a value ?.sup.t2.sub.NH is calculated from an equation ?.sup.t2.sub.NH=?.sup.t2.sub.HC/(?.sup.t1.sub.HC/?.sup.t1.sub.NH), and the calculated value ?.sup.t2.sub.NH is determined as a new slope in the linear area of the sensor output characteristics for an NH.sub.3 gas.

A particle filter for treating exhaust gases includes an SCR catalyst that, when in the presence of a reductant such as ammonia, promotes selective catalytic reduction of NO.sub.x; an active oxidation catalyst that promotes oxidation of hydrocarbons and carbon monoxide; and an oxygen storage catalyst that alternately stores and releases oxygen, enhances soot oxidation, and stores NOx at temperatures below optimal SCR functioning. The particle filter may be included in a system having an oxidation catalytic device (OCD) upstream of the particle filter, and optionally includes one or more SCR converters upstream and/or downstream of the particle filter, and/or an ammonia slip catalyst downstream of the particle filter. The system may further be adapted for operation under a high frequency injection fuel control with an OCD having substantial NOx storage material content, or an NSC for improving the efficiency tradeoffs between soot oxidation during filter regeneration and NO.sub.x reduction.

The invention relates to a gas purifier that removes moisture and oxygen from inert gases and reducing gases, for example, at sub-atmospheric pressures. The purifier can remove part per million levels of moisture in a gas stream to less than 100 parts per trillion by volume, and has a low pressure drop and a sharp breakthrough curve.