Promising System (promising + system)

Distribution by Scientific Domains

Selected Abstracts

3D Reconstruction of Real World Scenes Using a Low-Cost 3D Range Scanner

Paulo Dias
The article describes the mechanical and control issues addressed to physically achieve the 3D sensor used to acquire the data. It also presents the techniques used to process and merge range and intensity data to create textured polygonal models and illustrates the potential of such a unit. The result is a promising system for 3D modeling of real world scenes at a commercial price 10 or 20 times lower than current commercial 3D laser scanners. The use of such a system can simplify measurements of existing buildings and produce easily 3D models and ortophotos of existing structures with minimum effort and at an affordable price. [source]

Ozonation of 1,3,6-naphthalenetrisulfonic acid in presence of heavy metals

M Sánchez-Polo
Abstract A study was conducted of the mechanisms by which heavy metals, commonly present in industrial effluents, increase the purification effectiveness of ozone in the removal of organic contaminants of low biodegradability. For this purpose, the ozonation of 1,3,6-naphthalenetrisulfonic acid (NTS) in the presence of Ni(II), Fe(II), Mn(II), Zn(II), Sr(II), Cr(III), Cd(II), Hg(II), and Cu(II) was examined. The presence of small amounts of Mn(II), Fe(II), Ni(II), Zn(II), and Cr(III) was observed in the system, increasing the degradation rate of the NTS and transforming the dissolved organic matter into CO2. The mineralization of the organic matter was highly favored, especially in the first minutes of treatment. The results obtained appear to indicate that the activity of the metals in the NTS ozonation process is related to their reduction potential. Thus, metals susceptible to oxidation by ozone are potential promoters of NTS ozonation. The presence of Fe(II) or Mn(II) during NTS ozonation increased its degradation rate by 79% and 72% respectively. Moreover, the reaction kinetics of metal oxidation with ozone controls the increase in the purification effectiveness of these systems. The presence of radical scavengers (tert -butanol or bicarbonate) in the medium during the promoted ozonation of NTS showed a negative effect on this process, and the NTS degradation rate decreased with an increasing concentration of these inhibitors in the system. These results confirm that the degradation of NTS by ozone in the presence of heavy metals occurs by a radical mechanism. O3/Zn(II) and O3/Fe(II) systems were applied to the decontamination of urban waste waters. The presence of Zn(II) or Fe(II) during the ozonation produced a reduction during the first 5 min of treatment of 20% or 44%, respectively, in the concentration of dissolved organic matter present in the system. These results show that ozonation in the presence of heavy metals is a highly promising system for the purification of waste waters and industrial effluents. Copyright © 2004 Society of Chemical Industry [source]

Development and characterization of SCAR markers associated with a dominant genic male sterility in rapeseed

PLANT BREEDING, Issue 1 2008
D. F. Hong
Abstract Rs1046AB is a dominant genic male sterility (DGMS) line in rapeseed, in which the sterility has always been thought to be conditioned by the interaction of a male sterility gene (Ms) and its non-allelic restorer gene (Rf). This system provides not only a tool for assisting in recurrent selection but also a promising system for hybrid production. Based on previous studies, two amplified fragment length polymorphism markers linked with the Ms gene were converted into a dominant and a co-dominant sequence characterized amplified region (SCAR) marker, respectively. The putative linear order relationship of three dominant SCAR markers with the same genetic distance from the Rf gene, was also determined by an examination of whether the homologues of these markers are present or not in different lines carrying Rf. A bigger fragment generated by the closest marker linked to the Rf gene was observed in all lines carrying the recessive allele rf, suggesting that this marker is a co-dominant marker, which was further confirmed by nucleotide sequence comparison of these fragments. SCAR markers specific for Ms and Rf will be especially valuable in marker-assisted DGMS three-line breeding. [source]

Second law analysis of hydrogen liquefiers operating on the modified Collins cycle

M. T. Syed
Abstract Hydrogen liquefaction systems have been the subject of intense investigations for many years. Some established gas liquefaction systems, such as the precooled Linde,Hampson systems, are not used for hydrogen liquefaction in part because of their relatively low efficiencies. Recently, more promising systems employing the modified Collins cycle have been introduced. This paper reports on second law analyses of a hydrogen liquefier operating on the modified Collins cycle. Two different modifications employing the cycle in question were attempted: (1) a helium-refrigerated hydrogen liquefaction system and (2) a hydrogen-refrigerated hydrogen liquefaction system. Analyses were carried out in order to identify potential areas of development and efficiency improvement. A computer code capable of computing system and component efficiencies; exergy losses; and optimum number and operating conditions of compressors, expanders, aftercoolers, intercoolers, and Joule,Thomson valves was developed. Evaluation of the thermodynamic and transport properties of hydrogen at different temperature levels was achieved by employing a hydrogen property code developed by researchers at the National Bureau of Standards (currently NIST). A parametric analysis was carried out and optimal decision rules pertaining to system component selection and design were reached. Economic analyses were also reported for both systems and indicated that the helium-refrigerated hydrogen liquefier is more economically feasible than the hydrogen-refrigerated hydrogen liquefier. Copyright © 2001 John Wiley & Sons, Ltd. [source]