Primary meaning

The primary means of verifying a transition structure is to compute the vibrational frequencies. A saddle point should have one negative frequency. The vibrational motion associated with this negative frequency is the motion going... 

When a sample is injected into the carrier stream it has the rectangular flow profile (of width w) shown in Figure 13.17a. As the sample is carried through the mixing and reaction zone, the width of the flow profile increases as the sample disperses into the carrier stream. Dispersion results from two processes convection due to the flow of the carrier stream and diffusion due to a concentration gradient between the sample and the carrier stream. Convection of the sample occurs by laminar flow, in which the linear velocity of the sample at the tube s walls is zero, while the sample at the center of the tube moves with a linear velocity twice that of the carrier stream. The result is the parabolic flow profile shown in Figure 13.7b. Convection is the primary means of dispersion in the first 100 ms following the sample s injection. 

Much of the technology used in the reclamation of metals from metal-bearing wastes was developed by the mining iadustries. The primary means of recycling metal from metal and alloyed scrap is via pyrometaHurgy (see Metallurgy). 

Here are three primary means of controlling temperature for air-cooled heat exchangers. 

New vehicle emissions standards have served as the primary means for reducing vehicle emissions over... 

Although deaerators provide the primary means of mechanical deaeration, they are not of themselves immune from corrosive attack. Acid condensate (or MU water that has been subjected to split-stream softening or dealkalization and remains acid due to a lack of pH adjustment) can damage the deaerator. 

While river discharge is the primary means of transferring water from the land to the oceans, its magnitude pales in comparison to circulation within the oceans themselves. The total average... 

Transport in water is an important mechanism for transfer of biogeochemical elements between the atmosphere, land, and oceans. In particular, rain is the primary means of removal from the atmosphere for many substances, and rivers (and to some extent groundwater) convey weathering products and runoff from the land surface to the oceans. 

Unlike other biogeochemical elements, phosphorus does not have a significant atmospheric reservoir. Thus, while some amount of phosphorus is occasionally dissolved in rain, this does not represent an important link in the phosphorus cycle. River runoff is the primary means of transport between the land surface and oceans, and unlike the other elements discussed. 

The telephone is still one of the primary means of communication for clinical trial personnel. The telephone is used for both voice and digital communications. Voice communication is the normal person-to-person telephone call. Data communication with the telephone is the transmission of digital data from one location to another. Various software packages have been developed for this purpose. Using a voice modem connected to a telephone, a user on a local computer can connect to another remote computer that has a modem connected to a telephone and download or upload data files. Local and remote users can also communicate with text messages. The local computer operator can even control the remote computer for trouble-shooting or system update. 

GCMS Analysis. High resolution MS may be used as the primary means for quantitative determination of nitrosamines (1, 11-13). Usually it is more convenient and efficient to use the TEA for this purpose and employ GCMS for confirmation of identity of nitrosamines tentatively identified by GC-TEA. 

Chemistry is the science of matter, its properties, and changes. In your classroom work in chemistry, you will learn a great deal of the information that has been gathered by scientists about matter. But, chemistry is not just information. It is also a process for finding out more about matter and its changes. Laboratory activities are the primary means that chemists use to learn more about matter. The activities in the Laboratory Manual require that you form and test hypotheses, measure and record data and observations, analyze those data, and draw conclusions based on those data and your knowledge of chemistry. These processes are the same as those used by professional chemists and all other scientists. 

The RTD quantifies the number of fluid particles which spend different durations in a reactor and is dependent upon the distribution of axial velocities and the reactor length [3]. The impact of advection field structures such as vortices on the molecular transit time in a reactor are manifest in the RTD [6, 33], MRM measurement of the propagator of the motion provides the velocity probability distribution over the experimental observation time A. The residence time is a primary means of characterizing the mixing in reactor flow systems and is provided directly by the propagator if the velocity distribution is invariant with respect to the observation time. In this case an exact relationship between the propagator and the RTD, N(t), exists... 

Three primary processes are utilized for the removal of substances from the blood. Diffusion is the movement of a solute across the dialyzer membrane from an area of higher concentration (usually the blood) to a lower concentration (usually the dialysate). This process is the primary means for small molecules to be removed from the bloodstream, such as electrolytes. At times, solutes can be added to the dialysate that are diffused into the bloodstream. Changing the composition of the dialysate allows for control of the amount of electrolytes... 

For many years, the primary means of hydrilla control has been the application of herbicides to affected waterbodies. Various... 

Crystallization remains the primary means of controlling the polymorphic or solva-tomorphic state of a compound, and various groups have examined the influences of processing parameters on the identity and quality of the isolated form. Seeding was used to reduce the size of the metastable zone of eflucimibe, and thereby control the identity of the desired polymorphic identity of the product through a reduction in concomitant crystallization [16], Process improvements have been developed that were found to improve the filterability and enhance the bulk density of ranitidine Form-1 [17], while the variation of process parameters used in an oscillatory baffled crystallizer enabled better selection to be made between the metastable a- and /i-forms of (z.)-glutamic acid [18]. 

In a manner similar to that just described for differential thermal analysis, DSC can be used to obtain useful and characteristic thermal and melting point data for crystal polymorphs or solvate species. This information is of great importance to the pharmaceutical industry since many compounds can crystallize in more than one structural modification, and the FDA is vitally concerned with this possibility. Although the primary means of polymorph or solvate characterization s centered around x-ray diffraction methodology, in suitable situations thermal analysis can be used to advantage. 

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