Provenance research

There has been a growing demand for a lean NO catalyst ia order to decrease the relatively low NO emission of the lean bum engine sufftciendy to meet the future standards. Lean NO catalysts have been developed based on 2eolites (see Molecularsieves). Cu-promoted ZSM-5 2eolite has shown ability to reduce NO ia an exhaust having excess oxygen at an efficiency of 30 to 50% (153). Durability is not proven. Research has revealed that certain hydrocarbons are preferred for the reduction of NO, and that CO and H2 apparentiy do not reduce NO over such lean NO catalysts (154). 

Glascock, M. D. and Neff, H. (2003). Neutron activation analysis and provenance research in archaeology. Measurement Science and Technology 14 1516-1526. 

Xu, A. W., Wang, C. S., Chi, J. Q., et al. (2001). Preliminary provenance research on Chinese Neolithic pottery Huating (Xinyi County) and three Yellow River Valley sites. Archaeometry 43 35 17. 

Undeniably, one of the most widely recognized roles for obsidian involves provenance research (i.e., sourcing). Provenance research connects artifacts to their sources such that interpretations about the movement of obsidian can be made with a high degree of confidence. The process of obsidian artifact sourcing relies on making comparisons of one or more characteristics of obsidian artifacts with those same characteristics for all possible sources. In order to have a successful outcome, one must demonstrate that the characteristics of the artifact and the source are the same to the exclusion of all other possible sources. Usually, the greater the number of characteristics used in the comparison, the more reliable the result. 

Archaeologists have long sought methods for obsidian characterization that were rapid, reliable, non-destructive, and low-cost. Among the various methods investigated were visual techniques (79), density measurements (20), magnetic properties (27), thermoluminescence (22), fission-track analysis (25), Mossbauer spectroscopy (24), and natural radioactivity (25). Although some of the methods occasionally identified differences between sources, the overlap between sources was such that their overall reliability was unsatisfactory. The most successful method of characterization for obsidian provenance research has been compositional analysis (26). 

Since the mid-1960s, a variety of analytical chemistry techniques have been used to characterize obsidian sources and artifacts for provenance research (4, 32-36). The most common of these methods include optical emission spectroscopy (OES), atomic absorption spectroscopy (AAS), particle-induced X-ray emission spectroscopy (PIXE), inductively coupled plasma-mass spectrometry (ICP-MS), laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), X-ray fluorescence spectroscopy (XRF), and neutron activation analysis (NAA). When selecting a method of analysis for obsidian, one must consider accuracy, precision, cost, promptness of results, existence of comparative data, and availability. Most of the above-mentioned techniques are capable of determining a number of elements, but some of the methods are more labor-intensive, more destructive, and less precise than others. The two methods with the longest and most successful histoty of success for obsidian provenance research are XRF and NAA. 

In the past, the use of proven research technology was sufficient to approve most research and routine experiments did not receive the scrutiny that new experiments did. In the last few years, the NRC has required the investigators to formally review even standard procedures for possible hazards, to establish procedures to prevent these potential hazards from occurring, and to develop a response protocol. Worst case failure modes must be reviewed. It is enlightening to see the results of these analyses. It is frequently found that there is far more potential for failure than most would anticipate. The committee must review and approve of these hazard analyses. 

Kranenborg, K.G., and S.M.G. de Vries. 1995. Douglas-fir provenance research in The Netherlands 1966-67 lUFRO Series. Institute for Forestry and Nature Research (IBN-DLO) IBN Research Report 95/1, Wageningen, The Netherlands. 

Traffic safety research has a proud reputation with many critical pieces of innovative research, including quality evaluations of experimental initiatives leading to well-known step reductions in serious casualties. What has received relatively little attention, unfortunately, is how to take proven research and implement the accepted findings in practice to gain the benefits. 

Several research groups have built models using theoretical desaiptors calculated only from the molecular structure. This approach has been proven to be particularly successful for the prediction of solubility without the need for descriptors of experimental data. Thus, it is also suitable for virtual data screening and library design. The descriptors include 2D (two-dimensional, or topological) descriptors, and 3D (three-dimensional, or geometric) descriptors, as well as electronic descriptors. 

Biorational approaches have proven useful in the development of classes of herbicides which inhibit essential metaboHc pathways common to all plants and thus are specific to plants and have low toxicity to mammalian species. Biorational herbicide development remains a high risk endeavor since promising high activities observed in the laboratory may be nullified by factors such as limitations in plant uptake and translocation, and the instabiHty or inactivity of biochemical en2yme inhibitors under the harsher environmental conditions in the field. Despite these recogni2ed drawbacks, biorational design of herbicides has shown sufficient potential to make the study of herbicide modes of action an important and growing research area. 

The condition is usually non-specific and seldom traced to a single cause. This has been termed sick building syndrome. Despite much research, little has been proven but the building features associated with the condition are ... 

Medicinal chemistry has frequently drawn inspiration and important new leads from the examination of natural products, and this was proven to be the case once more. In 1992, researchers at Merck and Glaxo announced, almost simultaneously, the independent discovery of the same new class of natural products from two different fungi. As a consequence, the same family of natural products has two names - the zaragozic acids (Merck)4 or the squalestatins (Glaxo).5 A typical member of the family, zaragozic acid A (squa-lestatin SI) (1) was shown to have a tremendous affinity for squalene synthase (K, = 79 pM for rat microsomal squalene synthase) and could even lower serum cholesterol levels in vivo in a population of marmosets.6... 

Laser-induced fluorescence has proven to be the key to these pioneering studies of transuranic hexafluoride electronic state photophysics and photochemistry. This is a research area of unique opportunity in which fundamental and technical research interests strongly converge. 

A general conclusion from the review of the distribution of plutonium between different compartments of the ecosystem was that the enrichment of plutonium from water to food was fairly well compensated for by man s metabolic discrimination against plutonium. Therefore, under the conditions described above, it may be concluded that plutonium from a nuclear waste repository in deep granite bedrock is not likely to reach man in concentrations exceeding permissible levels. However, considering the uncertainties in the input equilibrium constants, the site-specific Kd-values and the very approximate transport equation, the effects of the decay products, etc. — as well as the crude assumptions in the above example — extensive research efforts are needed before the safety of a nuclear waste repository can be scientifically proven. 

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