Pulsed nozzle

Compute the pressure change inside the drillpipe at bottom when the pulse nozzle opens in each case. Give the optimal combinations for getting 200 to 250 psi pulses. 

A positive displacement mud motor is included in the downhole assembly between the bit and the MWD system. It develops a true power of 100 hp when the pulse nozzle is closed. What is the true power obtained when a 200-psi pulse is created The bit nozzle pressure loss will be neglected. Use... 

The interaction of dihalogen molecules XY with different acceptors B quite often leads to vicious chemical reactions. In most cases, the 1 1 complexes are extremely short-lived. To investigate these prereactive complexes experimentally in a collision-free environment, pulsed-nozzle, Fourier-transform microwave spectroscopy has turned out to be the ideal technique. Legon and coworkers prepared a large number of these complexes and performed detailed rotational spectroscopic analyses. Several series of simple molecules... 

Karpfen published a study of trends in halogen bonding between a series of amines and halogens and interhalogens [171]. Iodine-containing electron acceptors were not included. This study involved the use of RHF, MP2, and various DFT methods using extended, polarized basis sets and made extensive use of pulsed-nozzle, FT-microwave spectroscopic data (similar to that... 

Figure 3.9. Transient C02 formation rates on Pd30 (a) and Pd8 (b) mass-selected clusters deposited on a MgO(lOO) film at different reaction temperatures [74]. In these experiments CO was dosed from the gas background while NO was dosed via a pulsed nozzle molecular beam source. The turnover frequencies (TOFs) calculated from the experiments displayed in (a) and (b) are displayed in the last panel (c). C02 formation starts at lower temperatures but reaches lower maximum rates on the larger cluster. (Figure provided by Professor Heiz and reproduced with permission from Elsevier, Copyright 2005).

The molecular beam is formed by the supersonic expansion of gas through a pulsed nozzle. It is then collimated by two skimmers, and enters... 

Fig. 1. Schematic diagram of the multimass ion imaging detection system. (1) Pulsed nozzle (2) skimmers (3) molecular beam (4) photolysis laser beam (5) VUV laser beam, which is perpendicular to the plane of this figure (6) ion extraction plate floated on V0 with pulsed voltage variable from 3000 to 4600 V (7) ion extraction plate with voltage Va (8) outer concentric cylindrical electrode (9) inner concentric cylindrical electrode (10) simulation ion trajectory of m/e = 16 (11) simulation ion trajectory of rri/e = 14 (12) simulation ion trajectory of m/e = 12 (13) 30 (im diameter tungsten wire (14) 8 x 10cm metal mesh with voltage V0] (15) sstack multichannel plates and phosphor screen. In the two-dimensional detector, the V-axis is the mass axis, and V-axis (perpendicular to the plane of this figure) is the velocity axis (16) CCD camera.

Figure. 1. Schematic of essential components of the Exxon group cluster laser vaporization source and fast flow tube chemical reactor. On the far left is a 1 mm diameter pulsed nozzle that emits an -200 ysec long pulse of helium which achieves an average pressure of approximately one atmosphere above the sample rod. Immediately before the sample rod position the tube is expanded to 2 mm diameter. The length of this extender section can be varied form 6 mm to 50 mm depending upon the desired integration time for cluster growth. The reactor flow tube is 10 mm in diameter and typically 50 mm long. The reactants diluted in helium are added and mixed with the flow stream via the second pulsed valve.

The rotational spectrum of a hydrogen-bonded dimer formed by vinylacetylene and HC1 has been recorded by the pulsed-nozzle FT microwave technique149. The structure of the complex 72 confirms the geometry of the van der Waals complexes predicted on the basis of simple electrostatic models150. The distance between the HC1 proton and the centre of the triple bond (a in 72) is 3.629 A the same distance with an isolated triple bond is 3.699 A and with the double bond is 3.724 A150. 

The pre-equilibrium molecular complex formed in a mixture of ethylene and chlorine has been characterized using a pulsed nozzle FT microwave spectrometer. The rotational spectrum demonstrated the existence of a C2v-symmetrical complex 44 the CI2 molecule lies along the C2 axis of ethylene that is perpendicular to the molecular plane and interacts weakly with the jr-bond92. 

A schematic diagram of the spectrometer is shown in figure 10.16 its successfid operation depends critically upon the ability to achieve accurate timing for a sequence of several events. First, a short pulse of gas is produced from a pulsed-nozzle source, the gas travelling in a direction perpendicular to the axis of an evacuated Fabry Perot cavity, described later. This gas pulse lasts for about 1 ms, and the expansion in the cavity is in an essentially collision-free environment... 

Figure 10.16. Schematic block diagram of a pulsed-nozzle Fourier transform microwave spectrometer [15].

The gaseous sample was produced by using argon as a carrier gas, passing over CuCl or CuBr powder exposed to pulses from an ArF excimer laser, and injected through a pulsed nozzle into the Fabry Perot cavity. In contrast to the earlier work on the rare earth oxides mentioned above, the nozzle expansion was injected along the axis of the microwave cavity, rather than with the perpendicular orientation illustrated... 

Figure 10.38. Laser ablation pulsed nozzle source, for gas injection parallel to the axis of the Fabry-Perot cavity, described by Walker and Gerry [92].

In this approach material is laser desorbed from a sample probe in front of a pulsed nozzle. The desorption laser is typically (but not exclusively) a Nd YAG laser operated at its fundamental wavelength of 1064 nm. At this wavelength one does not expect photochemical interaction with any of the nucleobases. Laser desorption involves heating of the substrate, rather than the adsorbate. Therefore it is typically... 

Legon AC (1983) Pulsed-nozzle Fourier transform microwave spectroscopy of weakly bound dimers. Ann Rev Phys Chem 34 275-300... 

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