34 research outputs found
Recommended from our members
Environmental significance of biocatalytic conversion of low grade oils
Studies dealing with the interactions between extremophilic microorganisms and crude oils have led to the identification of biocatalysts which through multiple biochemical reactions catalyze desulfurization, denitrogenation, and demetalation reactions in oils. Concurrently, the oils are also converted to lighter oils. These complex biochemical reactions have served as models in the development of the crude oil bioconversion technology to be applied prior to the treatment of oils by conventional chemical processes. In practical terms, this means that the efficiency of the existing technology is being enhanced. For example, the recently introduced additional regulation for the emission of nitrogen oxides in some states restricts further the kinds of oils that may be used in burners. The biocatalysts being developed in this laboratory selectively interact with nitrogen compounds, i.e. basic and neutral types present in the oil and, hence, affect the fuel NOx production. This, in turn, has a cost-efficient influence on the processed oils and their consumption. In this paper, these cost-efficient and beneficial effects will be discussed in terms of produced oils, the lowering of sulfur and nitrogen contents, and the effect on products, as well as the longevity of catalysts due to the removal of heteroatoms and metal containing compounds found in crudes
Recommended from our members
The use of chemical markers in the evaluation of crude oil bioconversion products, technology, and economic analysis
Experimental data gathered over the past several years show that the interactions of microorganisms with crude oils are variable and depend on the microbial species and the chemical composition of crude oils. Systematic studies of chemical mechanisms by which selected microorganisms react with crude oils have led to the identification of biochemical markers characteristic of the interactions of microbes with oils. These biomarkers belong to several groups of natural products ranging from saturate and polyaromatic hydrocarbons containing heterocyclics to organometallic compounds. Chemical marker analyses indicate that the interaction of microbes with crude oils involves multiple chemical reactions resulting from the biochemical interactions between microbes and oils. Different interactions may influence the efficiency of processes in which single or mixed microbial species are used for the oil treatment and may also suggest possible combinations of biological and chemical technologies. Further, the biochemical conversions of oils can be monitored by these chemical markers, which is particularly useful in the optimization of biochemical processing, cost efficiency, and engineering studies. Recent results from these studies are discussed
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in
operation since July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). Like all previous SDSS releases, DR14
is cumulative, including the most recent reductions and calibrations of all
data taken by SDSS since the first phase began operations in 2000. New in DR14
is the first public release of data from the extended Baryon Oscillation
Spectroscopic Survey (eBOSS); the first data from the second phase of the
Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2),
including stellar parameter estimates from an innovative data driven machine
learning algorithm known as "The Cannon"; and almost twice as many data cubes
from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous
release (N = 2812 in total). This paper describes the location and format of
the publicly available data from SDSS-IV surveys. We provide references to the
important technical papers describing how these data have been taken (both
targeting and observation details) and processed for scientific use. The SDSS
website (www.sdss.org) has been updated for this release, and provides links to
data downloads, as well as tutorials and examples of data use. SDSS-IV is
planning to continue to collect astronomical data until 2020, and will be
followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected
Correlates of leisure-time physical activity in an elderly population in Singapore
American Journal of Public Health89101578-1580AJPE
Oviposition behaviour of Aedes albopictus in temephos and Bacillus thuringiensis israelensis-treated ovitraps
This study was conducted to determine the response of dengue vectors to ovitraps treated with temephos and Bacillus thuringensis israelensis (Bti) compared with untreated ovitraps which only contained seasoned tap water. The study was conducted at two sites: the natural breeding habitats where the ovitraps were exposed directly to sunshine and rain, and under shelter beneath a cabin without direct exposure. The ovitraps were placed for a period of five days at six different sites each in both conditions. The experiments were replicated three times. The results indicated that all mosquitoes breeding in the ovitraps were Aedes albopictus. There was no significant difference in the ovipositioning behaviour in the natural habitat, but there was a significant difference in the number of eggs laid in the ovitraps placed under the cabins. Though the mean number of eggs laid in traps in response to each treatment varied among the sites, the overall ovipositioning activity was not significantly different between sites when egg densities in the test ovitraps were averaged over the six-week ovitrapping period (site versus treatment effect) at p<0.05. The study also indicated that there was no ovicidal effect of both control agents since hatching of eggs occurred. Although eggs hatched, all larvae died eventually. The male to female ratio was 1:1 for both the sites. The study also showed that larval index is as effective as pupal index and can be used as a surveillance tool for the dengue vectors. It is concluded that containers treated with larvicide are not repellent to Aedes