The Aspirator

The aspirator (also called a water-jet pump) is one of the simplest and most economic means of obtaining a vacuum in the laboratory. It has no moving parts of its own (see Fig. 7.11), uses no electricity, and relies only on moving water to function. 

The aspirator is not a very fast pump (1-2 gallons/minute), nor does it create a powerful vacuum ( 10 mm Hg) (with proper liquid nitrogen trapping, aspirators can achieve vacuums as great as 10 2 torr). 1 It is ideally suited for emptying large containers of liquids down a sink or for supplying the vacuum necessary for a filter flask. 

If an aspirator has the appropriate attachment, it can be attached directly to a sink faucet so water exhaust can go down the drain. To prevent splashing that occurs when the water hits the sink s bottom, place a one-half to one-liter beaker under the aspirator filled with water. When the aspirator s water hits the prefilled beaker, the force will be absorbed and no splashing will occur. Otherwise, if the aspirator is going to be used at some location with no adequate drainage, a tube should be connected to the water exhaust so that the water can be channeled to a proper receptacle. 

The aspirator s pumping mechanism is quite sophisticated, and it all begins by water streaming past the water jet nozzle. By decreasing the internal diameter at the point where the water leaves the nozzle, there is an increase in water speed passing this point. Because the MFP of the gas and vapor molecules within the aspirator is much less than the pump dimensions, aerodynamic shear causes air movement in the desired direction. This air movement will occur regardless of whether there is direct contact of the air with the water or not. Additionally, because the boundary between the rushing water is quite turbulent, air is physi- 

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One problem with the analysis of salt samples is their tendency to clog the aspirator and burner assembly. What effect would this have on the analysis ... 

Clogging the aspirator and burner assembly decreases the rate of aspiration, decreasing the analyte s concentration in the flame. The result is a decrease in the signal and the introduction of a determinate error. 

Whisker reinforcement is a viable method of toughening composites. However, health considerations associated with the aspiration of fine, high-aspect-ratio whiskers raise serious concern about their widespread use. 

A stopcock and a drying tube were inserted into the hose between the glove bag and the aspirator. 

This type of lubrication provides the answer to why many mechanisms operate under conditions that are beyond the limits forecast by theory. It was previously thought that increasing pressure reduced oil film thickness until the aspirates broke through, causing metal-to-metal contact. Research has shown, however, that the effect on mineral oil of high contact pressure is a large increase in the viscosity of the lubricant. This viscosity increase combined with the elasticity of the metal causes the oil film to act like a thin solid film, thus preventing metal-to-metal contact. 

A dry ice-isopropyl alcohol trap was inserted before the aspirator to catch any uncondensed product The checkers also inserted a manometer between this trap and the aspirator, and maintained the pressure during the reaction at 130-170 mm. by careful adjustment of the regulator valve of the nitrogen cylinder. 

Before the actual distillation could be carried out, the flask was heated to approximately 95° and the residual formaldehyde removed at the aspirator. Only after the formaldehyde was removed could the pressure be reduced to that required for the distillation. 

The total consumption type of burner consists of three concentric tubes as shown in Fig. 21.5. The sample solution is carried by a fine capillary tube A directly into the flame. The fuel gas and the oxidant gas are carried along separate tubes so that they only mix at the tip of the burner. Since all the liquid sample which is aspirated by the capillary tube reaches the flame, it would appear that this type of burner should be more efficient that the pre-mix type of burner. However, the total consumption burner gives a flame of relatively short path length, and hence such burners are predominantly used for flame emission studies. This type of burner has the advantages that (1) it is simple to manufacture, (2) it allows a totally representative sample to reach the flame, and (3) it is free from explosion hazards arising from unbumt gas mixtures. Its disadvantages are that (1) the aspiration rate varies with different solvents, and (2) there is a tendency for incrustations to form at the tip of the burner which can lead to variations in the signal recorded. 

There are no apparent adverse reactions to ipecac. Although not an adverse reaction, a danger associated with any emetic is the aspiration of vomitus. 

With the mentor s help, the aspiring partner is more likely to make - as well as emotionally survive - the process of forging a new identity. With the support of a mentor, this process is likely to be accelerated. Lastly, mentoring should not end upon being made a partner it should continue, but perhaps with a different person and in a different form, such as peer mentoring. 

In Figure 11, the capillary with the plasma, is held in the left hand of the operator and the aspirating pipet is held in the right hand. Notice that the operator tilts the tube to... 

The aspiration levels inherited from the previous step, y, are used to guide the search process. Each agent i employs the corresponding aspiration level, y, and through the application of the learning methodology presented in Section IV tries to identift feasible hyperrectangles, Xf, that lead to performance consistent with y. ... 

After successive interactive relaxations, all of them leading to an insufficient number of (x,y) pairs that jointly satisfy the aspiration levels, we finally came down to the following revision of the perceived ideal ... 

The world population (P) continues to increase, though there is evidence that the rate of increase maybe dechning. The aspirations for the populations of developing coimtries to improve their economic circumstances and political pressure to ehminate excessive disparities of wealth in developed coimtries are such that average prosperity or economic activity (Wp) is also unhkely to show any marked reduction in the foreseeable future. If, as some contend, the world is close to, even beyond, its carrying capacity, then to prevent any further increases (or even to reduce it) it will be necessary to offset increases in P and Wp by proportionate decreases in P v... 

Ion extraction. The aspirated or laser ablated sample is transported from the sample introduction system into the center of the torch by a 1 1/min flow of Ar carrier gas where it is immediately dissociated and ionized by energy transfer with the hot -6000 K temperature of the surrounding Ar plasma. Ionization efficiencies are >95% for U and Th (Jarvis et al., 1992). For laser ablation sampling, helium may be employed as the carrier... 

Use of systemic corticosteroids is discouraged in patients with OA. However, in a subset of patients with an inflammatory component or knee effusion involving one or two joints, intraarticular corticosteroids can be useful as monotherapy or as an adjunct to analgesics. The affected joint can be aspirated and subsequently injected with a corticosteroid. The aspirate should be examined for the presence of crystalline formation and infection. A single joint should not be injected more than three to five times per year. 

Mineral Oil Hydraulic Fluids. Aside from the possibility of the development of pneumonitis following the aspiration of ingested mineral oil hydraulic fluid, little is known regarding the toxicity of these materials. Additional animal studies to identify the possible toxic effects of exposure to these materials may provide information relevant to the investigation of methods for reducing the toxic effects. 

Gerarde HW. 1963. Toxicological studies on hydrocarbons. IX. The aspiration hazard and toxicity of hydrocarbon mixtures. Arch Environ Health 6 329-341. 

The Tower of Alchemy is filled with intensely valuable occult principles, which are so often omitted, distorted, or unknown by other authors. The author also provides the reader with a series of exercises, which take the aspirant well beyond the scope of intellectual theory by actively involving the various levels of the personality in the practical application of the alchemical wisdom. It reveals a living tradition, whose aim is real transformation, not the mere accumulation of facts... 

Karpenko, Vladimir. Review of The aspiring adept Robert Boyle and his alchemical quest, by Lawrence M. Principe. In HYLE 6, no. 1 (2000) 181-186. rhttp //www.hvle.org/ioumal/issues/6/rev karp.html. 

Principe, Lawrence M. "The aspiring adept Robert Boyle and his alchemical quest." PhD thesis, Johns Hopkins Univ, 1996. 

Although the new Duke of Orleans was the wealthiest man in Europe, he was wildly popular with the French public. The house of Orleans had been the liberal voice of France for 150 years. Cousins of the French kings, the dukes opposed the monarchy s absolute power and the Catholic Church s monopoly on education and supported the aspirations of the growing middle class. Radicals talked of making the new duke regent or even king. 

Principe, Lawrence. 1998. The Aspiring Adept Robert Boyle and His Alchemical Quest Including Boyle s Lost Dialogue on the Transmutation of Metals. Princeton Princeton University Press. 

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