A kinetic study on the structural and functional roles of lanthana in iron-based high temperature water–gas shift catalysts

The structural and functional roles of varying amounts of lanthana in co-precipitated high temperature Fe₂O₃/Cr₂O₃/CuO water–gas shift catalysts were studied at 1 atm and 350–425 °C temperature range.     

A Versatile,Digital Sequencer for Programmed Electrical Heating of Nonflame Atomizers

ABSTRACT

A simple, inexpensive, yet flexible digital sequencer is described for the programming of electrically heated nonflame atomizers. The system provides four distinct periods of operation and a three step analog output for controlling the atomizer heating during desolvation, ashing and atomization. The sequencer is sufficiently versatile to allow it to be used with any nonflame atomizer with only minor modifications. Performance tests of the sequencer with the graphite braid nonflame atomizer are presented and illustrate that results comparable to those obtained with a laboratory minicomputer can be readily achieved.     

The thermal protection of a specific experimental instrument for monitoring of combustion conditions on the grate of municipal solid waste incinerators

The thermal protection of the specific experimental instrument for monitoring of combustion conditions on the grate of municipal solid waste incinerators (MSWI) represents a very important part of the assembled measuring system. The inner part of the instrument with control electronics and diverse sensors (temperature and flue gas concentration measurements) requires sufficient thermal protection against the high temperature environment of the combustion process with a surrounding temperature higher than 1200 °C. The influence of the high temperature environment is limited, but not fully eliminated, by thermal protection. The thermal protection is applied in two different ways. The standard thermal insulation with low thermal conductivity represents passive protection. The optimal thickness of the insulation itself partially defines the heat flux to the central part of the measuring system and its impacts upon increase of the inner temperature. The second type of protection, in an active mode, in addition to low conductivity, also provides heat storage. The full-scale thermal protection is designed by means of computer calculations with boundary and initial conditions or laboratory measurements within a similar environment to that on the grate of the MSWI. An additional aim of the sufficient thermal protection development is also to minimize the final size of the experimental instrument. The experimental trials have approved the functionality of the measuring instrument in high temperatures by keeping the inner temperature at the very low level.     

Contribution of the cholinergic basal forebrain to proactive interference from stored odor memories during associative learning in rats.

E. De Rosa and M. E. Hasselmo (see record 2000-13470-003) demonstrated that 0.25 mg/kg scopolamine (SCOP) selectively increased proactive interference (PI) from stored odor memories during learning. In the present study, rats with bilateral cholinergic lesions limited to the horizontal limb of the diagonal band of Broca, made with 192 IgG-saporin, were not impaired in acquiring the same olfactory discrimination task relative to control rats. Rats with bilateral IgG-saporin lesions to all basal forebrain cholinergic nuclei (BF) also showed no impairment in acquisition of this task. However, the BF-saporin rats were hypersensitive to oxotremorine-induced hypothermia and demonstrated an increased sensitivity to PI following a low dose of SCOP (0.125 mg/kg) relative to control rats. The results suggest that weaker cholinergic modulation after cholinergic BF lesions makes the system more sensitive to PI during blockade of the remaining cholinergic elements. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal activation of fatigue damage

The effect of temperature on the fatigue of aluminum alloys results from a combination of thermally induced changes in the microstructure and the intrinsic temperature dependence of the fatigue process. These two effects are separated for the first time, and it is shown that the intrinsic fatigue process is thermally activated. Two distinct regimes are identified. For fatigue lives <3 × 10⁶ cycles, the activation energy is 86 kJ/mole in 339 aluminum/15 pct Kaowool composites and 120 kJ/mole in unreinforced 5086 aluminum, i.e., in the range reported for diffusion in aluminum. For fatigue lives >3 × 10⁶ cycles, the activation energy is 240 kJ/mole. The magnitude of all three activation barriers decreases in direct proportion to the applied cyclic stress. These results are consistent with a dislocation model of jog formation at low cyclic stresses and the diffusion-assisted motion of jogs at high cyclic stresses. The activation volumes correspond to dislocation loop lengths of 10 to 30 nm.     

RECOGNITION OF TWO LIPASES FROM BARLEY AND GREEN MALT

Lipase was extracted from ground samples of germinating and ungerminated barley, using the detergent Triton X-100. Enzyme activity, measured by the release of oleic acid from radioactively labelled triolein, was approximately half that in suspensions of barley flour. Two distinct lipases, both active at neutral pHs, and having similar molecular weights (around 400,000) but differing in their ionic properties, were isolated from barley. The more abundant lipase was found mainly in the embryo, while the other was located in the endosperm. Both total and extractable lipase activity increased during germination.     

An Approach to the Modeling and Analysis of Software Production Processes

We propose an approach to the analysis and design of software production processes that is based on a new paradigm which we coin ‘PETAN’. It is a blend of concepts from Petri nets theory and activity nets theory. The paper reviews the relevant concepts from activity nets and demonstrates the applicability of the new paradigm by a sample implementation to real life software production processes through simulation using SLAM II language.     

TMM: Software Maintenance by Transformation

Porting an undocumented program without any source changes demonstrates the value of a transformational theory of maintenance. The theory is based on the reuse of knowledge.     

Factors influencing the effects of murine cytomegalovirus on the pancreas

BACKGROUND: As human cytomegalovirus (HCMV) infections are implicated in insulin-dependent diabetes mellitus (IDDM), the effects of murine (M)CMV infection of inbred mice on the pancreas are of interest. RESULTS: Inflammation and periacinar oedema peaked on day 3 and were replaced by a focal inflammation, but infected cells were rare. The islets were spared in C57BL mice. Insulitis normally seen in non-obese diabetic (NOD) mice was accelerated, but infected NOD mice did not become glycosuric. Isotypes of total and autoreactive antibodies suggested a shift to a Th 1 response (IgG2a) in all MCMV-infected mice. MCMV-induced pancreatitis was not affected by MHC genes but was similar or less severe in BALB/c mice. As these lack the Cmv1 gene, which provides a protective natural killer (NK) cell response in C57BL congenic mice, the C57BL background may carry a pancreatitis susceptibility gene able to counter NK-mediated restriction of viral replication. Consistently, congenic mice expressing Cmvl on a BALB/c background did not display pancreatitis, unless depleted of NK cells. In vivo treatment with soluble cytokine receptors suggested that interleukin 1 (IL-1) and/or tumour necrosis factor alpha contribute to acinar necrosis in C57BL mice.