Vortex liquid

For efficient extraction of macrolide and lincosamide residues from edible animal products, bound residues should be rendered soluble, most if not all of the proteins should be removed, and high recoveries for all analytes should be provided. Since tliese antibiotics do not strongly bind to proteins, many effective extraction methods have been reported. Sample extraction/deproteinization is usually accomplished by vortexing liquid samples or homogenizing semisolid samples with acetonitrile (136—139), acidified (136,140-142) orbasified acetonitrile (143), methanol (14, 144, 145), acidified (145-147) or basified methanol (148), chloroform (149-151), or dichloromethane under alkaline conditions (152). However, for extraction of sedecamycin, a neutral macrolide antibiotic, from swine tissues, use of ethyl acetate at acidic conditions has been suggested (153), while for lincomycin analysis in fish tissues, acidic buffer extraction followed by sodium tungstate deproteinization has been proposed (154). 

Extraction/deproteinization has been performed by either vortexing liquid samples or homogenizing semisolid samples with acetonitrile (227, 382, 383, 386-392), methanol (14, 393-395), methanol/water mixtures (396-401), ethyl acetate (384,402-406), dichloromethane (379,380,407), and acetone (408,409). Nonpolar organic solvents, such as isooctane (410, 411) and toluene (407), have also been reported to work extremely well for extracting salinomycin and dimetridazole from chicken tissues, respectively. Sample extraction with these nonpolar solvents yields a cleaner extract and an easier workup than extraction with commonly used polar solvents. However, selecting an extraction solvent is critical in establishing an analytical method because it is closely related to the cleanup systems. 

Carefully, inject 0.125mL of ethanolic DOPE into the vortexing tube in one swift motion with the tip of the pipettor below the surface of the vortexing liquid. 

Special features/comments complete high-throughput organic chemistry stand with synthesizer, SPE, balance, vortexer, liquid-liquid extraction module, vacuum centrifuge cooling with cold nitrogen gas multichannel (up to 8) pipette for solvent delivery reactive gas chemistry possible (rv can be pressurized up to 6 bar) 16 independent heating zones analytical port for in-line analysis (optional) on-board liquid-liquid extraction... 

In nematic liquid crystals, subjected to an external electric field at a certain critical voltage, a periodic distribution of the space charge Q and the electric potential appears, resulting in the corresponding periodic variations of the initial director orientation L and the hydrodynamic fiow with the velocity v. This effect, known as the electrohydrodynamic instability (EHDI), could be visualized optically as a periodic pattern of domains. Fig. 5.5. In a screen, domains become visible as black and white stripes perpendicular to the distortion plane, where periodic director deformation and vortex liquid crystal movement is observed. These stripes are caused by the periodicity of the change in the refractive index for an extraordinary ray due to variations in the director. Fig. 5.6. These spatially periodic variations of the refractive index (domains) were first detected by Zvereva and Kapustin [32]. Then Williams [33] investigated transverse domains in detail, and it is current practice to call this type of instability Williams or Kapustin-Williams [34] domains. 

Figure 1 is a sketch of the cyclone reactor. The liquid is fed tangentially into it (A). A gas mixture of SO3 and N2 is introduced into the reactor via a porous section of the cylindrical wall. The liquid phase is the continuous phase in the reactor, except near the cyclone-axis. Here, a gaseous core is found, due to a strong centripetal field, generated by the rotating liquid. This field causes gas bubbles to spiral from the wall to the cyclone-axis. Gas leaves the reactor via the upper outlet which is known as the vortex. Liquid leaves the reactor via the bottom outlet which... 

The pump may have formed a vortex at high flow rates or low liquid level. Does the vessel have a vortex breaker Does the incoming flow cause the surface to swirl or be agitated ... 

Reduce flow to design rates. Raise liquid level in suction vessel. Install vortex breaker in suction vessel. 

In a submerged-tube FC evaporator, all heat is imparted as sensible heat, resulting in a temperature rise of the circulating hquor that reduces the overall temperature difference available for heat transfer. Temperature rise, tube proportions, tube velocity, and head requirements on the circulating pump all influence the selec tion of circulation rate. Head requirements are frequently difficult to estimate since they consist not only of the usual friction, entrance and contraction, and elevation losses when the return to the flash chamber is above the liquid level but also of increased friction losses due to flashing in the return line and vortex losses in the flash chamber. Circulation is sometimes limited by vapor in the pump suction hne. This may be drawn in as a result of inadequate vapor-liquid separation or may come from vortices near the pump suction connection to the body or may be formed in the line itself by short circuiting from heater outlet to pump inlet of liquor that has not flashed completely to equilibrium at the pressure in the vapor head. 

FIG. 15-23 Power for agitation impellers immersed in single-phase liquids, baffled vessels with a gas-liquid surface [except curves (c) and (g)]. Curves correspond to (a) marine impellers, (h) flat-blade turbines, w = dj/5, (c) disk flat-blade turbines witb and without a gas-liquid surface, (d) curved-blade turbines, (e) pitcbed-blade turbines, (g) flat-blade turbines, no baffles, no gas-liquid interface, no vortex. 

Curve g is for disk flat-blade turbines operated in unbaffled vessels filled witb liquid, covered, so tbat no vortex forms. If baffles are present, tbe power characteristics at high Reynolds numbers are essentially tbe same as curve h for baffled open vessels, witb only a slight increase in power. 

In the transition region [Reynolds numbers, Eq. (18-1), from 10 to 10,000], the width of the baffle may be reduced, often to one-half of standard width. If the circulation pattern is satisfactory when the tank is unbaffled but a vortex creates a problem, partial-length baffles may be used. These are standard-width and extend downward from the surface into about one-third of the liquid volume. 

Vortex formation is a condition that arises from centrifugal acceleration acting on gravitational acceleration. The circular motion of the entire contents of the tank predominates over the flow of the liquid from the impeller. Flow orientation thus is important not only in cases of noticeable vortex formation, but... 

The distribution of velocity components (radial, tangential and axial) under conditions of mixing with baffles in comparison with the conditions of vortex formation is presented in Figure 12. The dashed lines in Figure 12 indicate non-baffled conditions. Comparison of the non-baffled and fully baffled velocity curves (solid line) leads to the following set of conclusions on vortex suppression when dealing with perfectly miscible liquids ... 

Solid partieles in liquids generally tend to settle to the bottom of a vessel under gravity due to their exeess density. To maintain a suspension, some form of agitation is normally provided together with wall baffles to prevent vortex formation in the swirling flow (Figure 2.14). 

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