Counting assembly

F. SAMPLE LOAD STATION AND DUAL CRYSTAL COUNTING ASSEMBLE... 

Ionisation probes. The operating principle of the ionisation probes is based on the fact that detonation products behind the detonation front are highly ionised, which makes them capable of conducting electric current. Thus, the arrival of the detonation wave at an ionisation prote (vsiiich is actually an electrical switch) enables the closure of the electric circuit. That allows a capacitor to discharge, and the associated voltage signal is used to start/stop the counting assembly of the electric counter. 

If two probes are inserted into an explosive charge at a known distance from each other (L the arrival of the detonation wave at the first probe will start the counting assembly while its arrival at the second probe will stop it. The time interval registered by the counting assembly (/) is the time needed by the detonation wave to pass the distance L. The detonation velocity is then calculated as the quotient of distance and time ... 

Other into the material whose shock wave velocity is to be determined. This distance limits the measuring length at vdiich the shock wave mean velocity is to be determined. The twined ends of the copper wires are placed into the holes made in the material so that the tip of the wire touches the copper foils. Since the copper wires are insulated, there is no electric contact between the wires and the foils. As the shock wave arrives, the varnish insulation of the copper wire will be destroyed, and thus the electric contact between the wire and the foil will be established. As soon as the electric contact is established, a voltage signal will be produced The signal will be recorded on the oscilloscope or will be used for the start/stop of the electronic counter counting assembly. 

In order to illustrate the selection methodology, two sample case studies are presented. The case studies show just how many different joining processes can be used on essentially the same design and how this affects part-count, assemblability and functional performance in support of DFA. 

Before setting about the task of developing such a model, the product development process requires definition along with an indication of its key stages, this is so the appropriate tools and techniques can be applied (Booker et al., 1997). In the approach presented here in Figure 5.11, the product development phases are activities generally defined in the automotive industry (Clark and Fujimoto, 1991). QFD Phase 1 is used to understand and quantify the importance of customer needs and requirements, and to support the definition of product and process requirements. The FMEA process is used to explore any potential failure modes, their likely Occurrence, Severity and Detectability. DFA/DFM techniques are used to minimize part count, facilitate ease of assembly and project component manufacturing and assembly costs, and are primarily aimed at cost reduction. 

Often, the manufacturing processes involved for composite structures fabrication are greatly simplified as compared to those for metal structures. Reduced part count results in a much lower assembly cost and overall reduction in the factory labor hours. 

Downhole Shocks Measurements. An accelerometer in the MWD telemetry tool measures transverse accelerations, or shocks, that may be damaging for the bottomhole assemblies. When acceleration exceeds a certain threshold, the event is signaled to the surface as being a shock. These events versus time or depth are displayed as shock count. This information is used as a warning against excessive downhole vibrations and to alert the driller to change the rpm or weight on the bit [106]. 

The concrete block walls of the cell housing the generator tube and associated components are 1.7 meters thick. The facility also includes a Kaman Nuclear dual-axis rotator assembly for simultaneous transfer and irradiation of reference and unknown sample, and a dual Na iodide (Nal) scintillation detector system designed for simultaneous counting of activated samples. Automatic transfer of samples between load station to the rotator assembly in front of the target, and back to the count station, is accomplished pneumatically by means of two 1.2cm (i.d.) polyethylene tubes which loop down at both ends of the system and pass underneath the concrete shielding thru a pipe duct. Total one-way traverse distance for the samples is approx 9 meters. In performing quantitative analysis for a particular element by neutron activation, the usual approach is to compare the count rates of an unknown sample with that of a reference standard of known compn irradiated under identical conditions... 

NC samples were irradiated for 3 min and TNT and HMX for 1 min at a 14 MeV neutron flux of approx 108n/cmasec, Simultaneous counting was performed by means of a matched dual 7.6x7.6cm flat Nal crystal detector assembly in conjunction with a Kaman Nuclear programmed timer system for automatic sample transfer, A one-min count time was usually sufficient to exceed 10 counts. The signal from each de-... 

The early notion that heat was a fluid called caloric was disproved in 1798 by Benjamin Thompson (later. Count Rumford). While minister of war in Bavaria and boring cannon, he observed that heat could be produced continuously and endlessly from a given mass of iron, and so it could not be a fluid. In one of his experiments, he used a team of two horses to turn a lathe that bored a hole in a 51-kg piece of cannon iron. The iron was immersed in a wooden box containing 18.77 lb. of water. The assembly was initially at 60.°F and 1.00 atm. 

An aerosol size distribution can, therefore, be described in terms of the count median diameter, d, and the geometric standard deviation, a These parameters were obtained from experimental data using a diffusion battery method (Busigin et al., 1980). A diffusion battery is an assembly of a number of cylindrical or rectangular channels. The relative penetration of aerosols through different sizes of diffusion batteries at specified flow rates allows the aerosol size distribution to be calculated. 

An assembly of textile fibres to form a thread. Yams may be single, ply or cabled, the commonest used in weaving being single yams. Yarn Count... 

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