Nondestructive removal

To date, Evans and co-workers have examined a series of transformations that result in the mild, nondestructive removal of the oxazolidone auxiliaries from (176). Basic hydrolysis, transesterification, and reduction of (176) are all viable chemical operations in these systems. 

Corrosion. The tubes in the LTV evaporator were installed with Swenson rubber grommet packing commonly used for Karbate tubes in acid evaporators. This both insulated the tubes from galvanic corrosion and allowed nondestructive removal for weighing. Corrosion rates were estimated both from weight loss of the tubes and from International Nickel Co. test spools located both in the vapor space and immersed in the liquid in the blowdown tank. 

V-a./J-Enoylsultarns derived from camphor can be catalytically osmylated to the corresponding diols. Very high auxiliary-induced stereoselectivities are achieved with (E)- as well as (Z)-a,/l-enoyl substrates. Acetalization of the resulting 1,2-diols followed by flash chromatography or crystallization provides pure (>99% d.r.) acetonides. Subsequent nondestructive removal of the chiral auxiliary can be effected by basic hydrolysis or reductive treatment 5. 

Nondestructive Removal of the Auxiliary. Primary alcohols are obtained by Lithium Aluminum Hydride reduction of the corresponding chiral esters. Also, hydrolysis of the auxiliary under basic conditions, 2N KOH in methanol, " provides the carboxylic acid and recovered alcohol (3). 

Photographic and written documentation of the existing condition and all changes were made. Spurious materials (cement, plaster, and Fiberglas that could be nondestructively removed) were removed. This removal reduced weight and kinetic load induced by the masses and opened the interior cavity for access. 

Imide enolates derived from (5)-valinol and (15,2/f)-norephe-drine and obtained by either LDA or Sodium Hexamethyldisi-lazide deprotonation (eq 24) exhibit complementary and highly diastereoselective alkylation properties. Mild and nondestructive removal of the chiral auxiliary to yield carboxylic acids, esters, or alcohols contributes to the significance of this protocol in small-and large-scale synthesis. ... 

Table VII lists threadlocking anaerobics and gives a general description of popular grades it is not comprehensive. This product type represents the majority of anaerobic business. Once cured in a nut and bolt or screw assembly, anaerobics prevent loosening due to vibration or impact. Data demonstrating these properties are voluminous. Threadlocking products come in different strengths and viscosities, required because of the variety of bolt and screw sizes. Smaller screws, for instance, require a lower strength product to allow nondestructive removal. Viscosities vary to accomodate thread density and the need to wick into preassembled fasteners. Threadlocking performance is measured in terms of the torque required to loosen the fastener after cure (breakaway torque) and the torque required to turn the nut or screw after breakaway (prevailing-out torque).

Usually nondestructive sample preparation may involve material removal... 

Rutherford Backscattering (RBS) provides quantitative, nondestructive elemental depth profiles with depth resolutions sufficient to satisfy many requirements however, it is generally restricted to the analysis of elements heavier than those in the substrate. The major reason for considering depth profiling using FIXE is to remove this restrictive condition and provide quantitative, nondestructive depth profiles for all elements yielding detectable characteristic X rays (i.e.,Z> 5 for Si(Li) detectors). 

Precipitation is nonselective in that compounds other than those targeted may be removed. Both precipitation and flocculation are nondestructive and generate a large volume of sludge which must be disposed of. Coagulation, flocculation, sedimentation, and filtration, are typically followed by chlorination in municipal wastewater treatment processes. 

In TLC the detection process is static (sepaurations achieved in space rather than time) and free from time constraints, or from interference by the mobile phase, which is removed between the development and detection process. Freedom from time constraints permits the utilization of any variety of techniques to enhance detection sensitivity, which if the methods are nondestructive, nay be applied sequentially. Thus, the detection process in TLC is nore flexible and variable than for HPLC. For optical detection the minimum detectable quantities are similar for both technlqpies with, perhaps, a slight advantage for HPLC. Direct comparisons are difficult because of the differences in detection variables and how these are optimized. Detection in TLC, however, is generally limited to optical detection without the equivalent of refractive... 

Analytical techniques for the quantitative determination of additives in polymers generally fall into two classes indirect (or destructive) and direct (or nondestructive). Destructive methods require an irreversible alteration to the sample so that the additive can be removed from the plastic material for subsequent detention. This chapter separates the additive wheat from the polymer chaff , and deals with sample preparation techniques for indirect analysis. 

In many instances when analyzing archaeological objects, removing a sample may be aesthetically deleterious to the object, therefore rendering the removal of samples totally inadequate, or allowing the removal of extremely small samples so as not to affect the appearance of the objects. In such cases it is often necessary to turn to specialized techniques, such as nondestructive techniques, which do not require the removal of samples altogether, or to micro analytical techniques, for which extremely small samples are needed (see Textbox 11). 

The reluctance of museum curators and collectors to allow permanent damage to antiquities was, until not long ago, the main reason for the small amount of analytical work done on ancient coins. This was understandable since performing chemical analysis required removing a sample from the coin or damaging its surface, which meant either the destruction or defacement of, at least, a portion of a coin. More recently, however, a number of nondestructive methods of analysis such as neutron activation, X-ray fluorescence, and some techniques of surface analysis have been successfully applied to obtain information about ancient coins and the people and societies involved in their production (Carter 1993 Barrandon et al. 1977). 

A. Devaraj, M. Izzetoglu, K. Izzetoglu, S. C. Bunce, C. Y. Li, and B. Onaral. Motion artifact removal in FNIR spectroscopy for real-world applications. In Nondestructive Sensing for Food Safety, Quality, and Natural Resources. Edited by Chen, Yud-Ren Tu, Shu-I. Proceedings of the SPIE, Volume 5588, pp. 22f-229 (2004)., pages 224-229, October 2004. 

IR-T/A techniques would also have yielded useful results, but only at the expense of carrying out a sampling procedure, i.e, removing a small amount of material from an object, thus destroying the integrity of the object and then subjecting the sample to a preparation procedure. In contrast, PBDS is nondestructive. The examples which are briefly given below similarly point out the utility of PBDS, but in addition some of the materials could not have been examined by IR-T/A at all. 

Eco Logic is considering other approaches to address the removal of agent heels from projectiles. Heels may not be present in every projectile. One potential alternative is the use of systems such as portable x-ray analyzers to nondestructively characterize projectiles that have heels for segregation in the storage facility. This approach could minimize unnecessary processing in the PWS of projectiles not having heels. 

A residuum (pi. residua, also shortened to resid, pi. resids) is the residue obtained from petroleum after nondestructive distillation has removed all the volatile materials. The temperature of the distillation is usually maintained below 350°C (660°F), since the rate of thermal decomposition of petroleum constituents is minimal below this temperature but the rate of thermal decomposition of petroleum constituents is substantial above 350°C (660°F) (Speight, 1999, and references cited therein). 

Infrared and Raman spectroscopy are nondestructive, quick and convenient techniques for monitoring the course of solid-phase reactions, and have therefore been widely used for the characterization of polymer supports and supported species [156-160]. In fact, the application of infrared spectroscopy in solid-phase synthesis has received much attention and has been the subject of several recent reviews [127, 128, 161-164]. Reactions involving either the appearance or disappearance of an IR-active functional group can be easily monitored using any of the IR techniques described in this section. Some beads are typically removed from the reaction mixture, then they are quickly washed and dried prior to IR analysis. Traditionally, polymer supports are diluted and ground with KBr, then conventional FT-IR analysis of the KBr disk is carried out Although this is a commonly used... 

Macro visual examination is done with the unaided eye or low power (up to 2 OX) magnification. An item may need to be cleaned prior to examination. Fracture origins and location of samples to be removed for further analysis are determined by macro visual examination. Nondestructive evaluation methods may be necessary for more accurate determinations (see Step 4). 

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