Absorption apparatus

Ammonia is absorbed in a falling film of water in an absorption apparatus and the film is disrupted and mixed at regular intervals as it flows down the column. The mass transfer rate is calculated from the penetration theory on the assumption that all the relevant conditions apply. It is found from measurements that the muss transfer rate immediately before mixing is only 16 pet cent of that calculated from the theory anil the difference has been attributed to the existence of a surface film which remains intact and unaffected by the mixing process. If the liquid mixing process lakes place every second, what thickness of surface film would account for the discrepancy, ... 

Mixtures of acetylene and dinitrogen oxide used to create flames in atomic absorption apparatus detonate in the presence of perchloric acid. 

Puacz et al. (1995) developed a catalytic method, based on the iodine-azide reaction, for the determination of hydrogen sulfide in human whole blood. The method involves the generation of hydrogen sulfide in an evolution-absorption apparatus. In addition, the method allows for the determination of sulfide in blood without interference from other sulfur compounds in blood. A detection limit of 4 g/dm3 and a percent recovery of 98-102% were achieved. Although the accuracy and precision of the catalytic method are comparable to those of the ion-selective electrode method, the catalytic method is simpler, faster, and would be advantageous in serial analysis. 

Nevertheless, we were able to develop a transient absorption apparatus involving IR probe radiation that is suitable for gas phase studies, as have a number of other groups either coincident with or subsequent to our work [1]. In the remainder of this article we will discuss the apparatus and the results of our studies on three prototypical metal carbonyl species Fe(C0>5, Cr(C0>5 and Mn2(CO)] o The discussion in this article will center on the nature of the photolytically generated coordinatively unsaturated species, their kinetic behavior and photophysical information regarding these species. This latter information has enabled us to comment on the mechanism for photodissociation in these systems. Since most of the results that will be discussed have been presented elsewhere [3-10], we will concentrate on a presentation of data that illustrates the most important features that have come out of our research and directly related research regarding the kinetics, photophysics and photochemistry of coordinatively unsaturated metal carbonyls. 

The Absorption Apparatus. Filling this Apparatus.—Small thin-walled glass absorption tubes with two ground glass stoppers... 

The Aspirator.—Since the closely packed absorption vessels offer a resistance equivalent to several centimetres of water to the gas stream there must be sufficient pressure at the junction of the constricted part of the combustion tube with the calcium chloride tube to overcome this resistance when the absorption apparatus is opened. But to create this pressure would seriously endanger the quantitative determination of the products of combustion because the high concentration of these set up at this point would increase the possibility of leakage. The most effective remedy consists in maintaining within the junction a pressure as near as possible to the atmospheric pressure. For this purpose an aspirator is attached to the apparatus so that a determined, easily variable diminished pressure can be maintained in the absorption apparatus. 

Switch on the current in the electric furnace while the absorption apparatus is cooling, at the same time passing air through the tube at the rate employed during analyses.1 If the tube has not previ-... 

Now open the cocks on the absorption apparatus and the cock on the aspirator, and make sure that the previously determined rate of flow of the bubbles in the counter is maintained. A difference of 1-2 units in the number of bubbles passing in ten seconds has no detrimental effect. If necessary, restore the former rate of flow of the bubbles by lowering or raising the levelling tube of the aspirator. (Collect the water which drops from the aspirator during the analysis in a 500 c.c. measuring cylinder). Then place in position the copper-wire frame which conducts the heat from the furnace to the constricted part of the tube and to the side tube of the calcium chloride tube so that the metal touches the glass. Condensation of water in the side tubes is thus absolutely prevented. 

Weighing the Absorption Apparatus.—Prepare the absorption apparatus for weighing and weigh in exactly the same way as described on p. 63. 

Nanosecond Absorption Spectroscopy Absorption apparatus, 226, 131 apparatus, 226, 152 detectors, 226, 126 detector systems, 226, 125 excitation source, 226, 121 global analysis, 226, 146, 155 heme proteins, 226, 142 kinetic applications, 226, 134 monochromators/spectrographs, 226, 125 multiphoton effects, 226, 141 nanosecond time-resolved recombination, 226, 141 overview, 226, 119, 147 probe source, 226, 124 quantum yields, 226, 139 rhodopsin, 226, 158 sample holders, 226, 133 singular value decomposition, 226, 146, 155 spectral dynamics, 226, 136 time delay generators, 226, 130. 

Induction Periods. Induction periods for squalane oxidation were measured using an automatic recording oxygen absorption apparatus (23). 

Minshall and Helson (7) of the Dominion Department of Agriculture at Ottawa, Canada, have studied the physiological action of petroleum naphtha on carrots, parsnips, and several weeds including mustard. They used infrared absorption apparatus, and by means of readings taken at 10-second intervals following oil application, determined that photosynthesis ceased abruptly for all plants studied. With parsnips, photosynthesis was resumed within 30 minutes after application it was one third of norm at the end of 3 hours, and at the end of 48 hours reached approximately the original rate before treatment. Parsnips did not wilt following treatment. The common mustard plant had a... 

To effect this measurement the slit bandwidth of the atomic absorption apparatus is 1 nm. What does this parameter represent ... 

The absorption apparatus is then closed by the pinchcock and disconnected from the combustion apparatus at the rubber tubing. The burners under the spiral and oxide are gradually turned down so that the combustion tube cools with a slow stream of C02 passing through it this prevents the Cu spiral from being oxidised. The reservoir is raised until the liquid in it is at the same level as the liquid in the nitrometer, and a thermometer is hung beside the latter. The levels of the liquid in the reservoir and nitrometer are adjusted occasionally, and in about an hour the volume of N is read and the temperature and atmospheric pressure noted. 

Procedure. A stout-necked, round-bottomed flask of about 300 c.c. capacity is closed by a rubber stopper through which pass (1) a tapped funnel, (2) a glass tube drawn out to a point and reaching almost to the bottom of the flask and (3) a glass tube connected with a vertical spiral condenser. The end of the condenser is tightly connected with either a bulbed tube of about 75 c.c. capacity or other absorption apparatus. 

A U-tube containing calcium chloride in one limb and soda-lime in the other, to protect the absorption apparatus from the carbon dioxide of the air and from the moisture of the aspirator. 

Nitric acid is manufactured at the present day by one of three processes (i) By the direct oxidation of nitrogen in the electric arc as indicated in connection with the fixation of nitrogen (ii) By oxidation of ammonia as indicated in connection with that compound and (iii) By the decomposition of sodium nitrate with sulphuric acid. Some chemical changes involved in the third reaction have just been discussed. The plant employed consists of (i) the distilling apparatus (ii) the condensing system (iii) the receiving vessel (iv) the bleaching system and (v) the absorption apparatus. 

The determination of arsenic by atomic absorption spectrometry with thermal atomisation and with hydride generation using sodium borohydride has been described by Thompson and Thomerson [29], and it was evident that this method couldbe modified for the analysis of soil. Thompson and Thoresby [30] have described a method for the determination of arsenic in soil by hydride generation and atomic absorption spectrophotometry using electrothermal atomisation. Soils are decomposed by leaching with a mixture of nitric and sulfuric acids or fusion with pyrosulfate. The resultant acidic sample solution is made to react with sodium borohydride, and the liberated arsenic hydride is swept into an electrically heated tube mounted on the optical axis of a simple, lab oratory-constructed absorption apparatus. 

C6. Conway, E. J., and Byrne, R., Absorption apparatus for microdetermination of certain volatile substances microdetermination of ammonia. Biochem. J. 27, 419 (1933). 

Figure 1. A schematic for the CO laser resonance absorption apparatus...

Recent ultrasonic measurements on S02 by Bass, Winter, and Evans [258] confirms the earlier observations of multiple relaxation [259,260] and extends the temperature range to 1090°K. As T increases, the relaxation time for the bending mode increases with increasing temperature, while that for the stretching modes decreases in the normal manner. Shields and Anderson [261], using an improved absorption apparatus, have studied pure S02 and its mixtures with argon. Under careful inspection, the results are shown to... 

Atomic absorption spectrometry was introduced approximately 18 years ago into laboratories concerned with the analysis of materials connected with ferrous metallurgy. Thus, literature references for this area of analysis only cover this period [89, 103, 134, 135, 151, 154]. Atomic absorption apparatus has been improved significantly during the past decade. Analysts have made demands upon manufacturers which have led to the development of sophisticated electronics and improvements in optical systems [33, 34,52, 53,59,148,149]. 

Experiment 61. — Construct and arrange an apparatus like Fig. 52 to collect the gas. The apparatus shown in Fig. 55 is used to prepare a solution of the gas, and is the same as shown in Fig. 52, except that B passes into the absorption apparatus, FG. Instead of F, the apparatus //. shown in Fig. 56, may be used. The flask A stands on a sand bath, and the gas is collected in D by downward displacement, exactly as in the collection of chlorine. 

---