We present optical spectra of four intermediate mass candidate young stellar objects that have often been classified as Herbig Ae/Be stars. Typical Herbig Ae/Be emission features are not present in the spectra of these stars. Three of them, HD 36917, HD 36982 and HD 37062 are members of the young Orion Nebula Cluster (ONC). This association constrains their ages to be ≤ 1 Myr. The lack of appre...

the task of balancing of assembly lines is well-known in mass production system but this problem is np-hard even for the simple straight line. therefore, utilizing heuristic methods for these problems is totally unquestionable. furthermore, in line with balancing problems, heuristic methods are the foundation of the metaheuristic methods, thus it seems to be necessary to use more efficient heur...

an on-line automated method for photodegradation studies of isoproturon, diuron, atrazine, fenitrothion, and metoxuron by means of liquid chromatography/mass spectrometry (lc/ms) with particle beam (pb) interface is described. surface water samples were first spiked with 50 µg/l of each pesticide and then exposed to the radiation of the medium-pressure mercury lamp. next, in regular intervals o...

Phosphopeptides tagging reactions by dinuclear zinc(II) complexes (1,3-bis[bis(2-pyridylmethyl)amino]-propan-2-olato dizinc(II)3+, called tag) were performed with a dual-channel microsprayer in electrospray ionization mass spectrometry. The reaction is first studied ex situ and analyzed with a commercial electrospray source. In situ reactions (i.e., inside the Taylor cone) were achieved with a ...

We show that the mass of ionized gas in the broad-line regions (BLRs) of luminous quasars is at least several hundred M , and probably of the order of 10 3–104 M . BLR mass estimates in several existing textbooks suggest lower values but pertain to much less luminous Seyfert galaxies or include only a small fraction of the ionized/emitting volume of the BLR. The previous estimates also fail to ...

To perform on-line monitoring of the absolute weight-averaged mass, Mw, of the polymers produced in a polymerization reaction, refractometer (RI), ultraviolet absorbance (UV), and time-dependent static light scattering (TDSLS) detectors were placed in series, and a diluted stream of reactant solution was made to flow through them. The technique allows rapid determination of time-dependent react...

Real-time and on-line continuous monitoring of reactants, intermediates, and final products for dicarbonyl compound bioreduction in a continuous plug flow reactor packed with baker's yeast (Saccharomyces cerevisiae) whole cells immobilized on calcium alginate beads was performed by membrane introduction mass spectrometry (MIMS) via selective ion monitoring.

We present optical spectra of 45 intermediate mass Herbig Ae/Be stars. Together with the multi-epoch spectroscopic and photometric data compiled for a large sample of these stars and ages estimated for individual stars by using pre-main sequence evolutionary tracks, we have studied the evolution of emission line activity in them. We find that, on average, the Hα emission line strength decreases...

Evaporating sessile drops remain pinned at the contact line during much of the evaporation process, and leave a ring of residue on the surface upon dryout. The intensive mass loss near the contact line causes solute particles to flow to the edge of the droplet and deposit at the contact line. The high vapor diffusion gradient and the low thermal resistance of the film near the contact line are ...