A four-way catalytic system for control of emissions from diesel engine

The pollution caused by diesel-fuelled vehicles has become a subject of global concern. Presently, various separate technologies such as diesel oxidation catalyst, diesel particulate filter, selective catalytic reduction and ammonia selective catalytic reduction are used to control these pollutants. The four-way catalytic (FWC) system integrates all the separate control systems into a single compact unit. FWC technique using a combination of oxidation–reduction catalysts under various strategies has been investigated to simultaneously remove CO, HC, PM and NOx emitted from diesel engines. An oxidation catalyst (La_0.6K_0.4CoO₃) was prepared by two different methods (sol–gel and co-precipitation). The reduction catalysts: Ag/Al₂O₃ and Cu-ZSM5 were synthesized by impregnation and ion-exchange method, respectively. The FWC was characterized by N₂-sorption, X-ray diffraction, Fourier transform spectroscopy and scanning electron microscopy. The catalytic activities of FWC containing double-layer of catalysts were evaluated in a fixed-bed-tubular-reactor. The highest catalytic activity resulted by the two-layered system of La_0.6K_0.4CoO₃ (sol–gel)?+?Cu-ZSM5 showing 100% NO conversion to N₂ at 415°C, maximum-temperature of soot-combustion at 410°C, complete C₃H₈ conversion at 450°C and 100% CO conversion at 388°C. Maximum NO conversion was maintained up to 427°C; conversion started decreasing with further increase in temperature and 75.4% conversion remained up to 450°C. The performance of double-layered-catalytic-system was as follows: La_0.6K_0.4CoO₃(sol–gel)?+?Cu-ZSM5?>?La_0.6K_0.4CoO₃(sol–gel)?+?Ag/Al₂O₃?>?La_0.6K_0.4CoO₃(co-ppt)?+?Ag/Al₂O₃?>?La_0.6K_0.4CoO₃(co-ppt)?+?Cu-ZSM5.     

Video Relighting Using Infrared Illumination

Inappropriate lighting is often responsible for poor quality video. In most offices and homes, lighting is not designed for video conferencing. This can result in unevenly lit faces, distracting shadows, and unnatural colors. We present a method for relighting faces that reduces the effects of uneven lighting and color. Our setup consists of a compact lighting rig and a camera that is both inexpensive and inconspicuous to the user. We use unperceivable infrared (IR) lights to obtain an illumination bases of the scene. Our algorithm computes an optimally weighted combination of IR bases to minimize lighting inconsistencies in foreground areas and reduce the effects of colored monitor light. However, IR relighting alone results in images with an unnatural ghostly appearance, thus a retargeting technique is presented which removes the unnatural IR effects and produces videos that have substantially more balanced intensity and color than the original video.     

On the synthesis of LaCl3 catalysts for oxidative chlorination of methane

LaCl₃ is an active and selective catalyst for oxidative chlorination of methane to methyl chloride, generated in situ by chlorination from LaOCl. The latter is prepared by precipitation of La(OH)₂Cl and subsequent calcination. The synthesis route was modified by using different bases in order to synthesize high surface area LaOCl catalyst precursors. Ammonium hydroxide and the organic bases tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide are used as precipitating agents. The marked increase of the specific surface area by using organic bases indicates also that they may act as templating agents. After chlorination the specific surface areas of pure LaOCl samples decrease drastically, lanthanum carbonate, however, acts as structural promoter stabilizing the specific surface area during chlorination.     

Epoxy and cyclopropenoid fatty acids in Amaranthus paniculatus seed oil

Amaranthus paniculatus (L) syn Amaranthus caudatus, (L) seed oil contains palmitic (19-4%), stearic (3-9%), oleic (21-9%), linoleic (43-9%), vernolic (7-8%), malvalic (1-5%) and sterculic (1-6%) acids. These fatty acids were characterised by IR, NMR, MS and GLC techniques and by chemical degradations.     

Prediction of PTZ-induced seizures using wavelet-based residual entropy of cortical and subcortical field potentials

Our proposed algorithm for seizure prediction is based on the principle that seizure build-up is always preceded by constantly changing bursting levels. We use a novel measure of residual subband wavelet entropy (RSWE) to directly estimate the entropy of bursts, which is otherwise obscured by the ongoing background activity. Our results are obtained using a slow infusion anesthetized pentylenetetrazol (PTZ) rat model in which we record field potentials (FPs) from frontal cortex and two thalamic areas (anterior and posterior nuclei). In each frequency band, except for the theta-delta frequency bands, we observed a significant build-up of RSWE from the preictal period to the first ictal event (p < or = 0.05) in cortex. Significant differences were observed between cortical and thalamic RSWE (p < or = 0.05) subsequent to seizure development. A key observation is the twofold increase in mean cortical RSWE from the preictal to interictal period. Exploiting this increase, we develop a slope change detector to discern early acceleration of entropy and predict the approaching seizure. We use multiple observations through sequential detection of slope changes to enhance the sensitivity of our prediction. Using the proposed method applied to a cohort of four rats subjected to PTZ infusion, we were able to predict the first seizure episode 28 min prior to its occurrence.     

A diffusional interphase in layered polyesters

The properties of the birefringent interphase in the laminates of unsaturated polyester resin were characterized using polarized microscopy and a birefringence compensation technique. The thickness of the interphase was found to depend on the casting conditions, and values ranging from 0.004 to 0.25 mm were observed. The location and dependence of the thickness on the curing conditions suggested that the interphase formed due to the diffusion of constituents from the liquid resin of the second layer into the previously cured layer. The index of refraction of the interphase was higher than that of the polyester above and below it. There was a sharp front marking a boundary of the interphase from the rest of the resin. These observations indicated characteristics of non-Fickian interfacial diffusion. Qualitative estimation of the birefringence in the interphase by interference colors indicated the first-order optical retardation. The birefringence was hypothesized to be due to residual stresses resulting from the fabrication procedure. The birefringence was quantified using a Berek compensator to measure the stresses. The approximate stress values were found to be in the range of 10–40 MPa. © 1996 John Wiley & Sons, Inc.