History of lead

Just to reiterate what we have said, neutron capture is the only valid channel towards the extreme complexity of gold (Z = 79). Reactions involving charged particles are energetically unfavourable and moreover inhibited by insurmountable electrical barriers. Because of the strong electrical repulsion between heavy nuclei (which thus contain many protons), the classic thermonuclear fusion reactions are ineffective, and we are forced to accept the idea that nuclear species beyond iron are produced by a process other than thermonuclear fusion. This process is neutron capture. 

We have seen that, globally speaking, nuclei above iron can be divided into two groups those resulting from the s process and those originating in the r process. A third mechanism called the p process only affects a minority of nuclear isotopes, producing a few rare species rich in protons. 

The term s process is an abbreviation for slow neutron capture process . Here, capture is slow relative to the characteristic time for internal transformation of the neutron into a proton (radioactive decay). Between two neutron captures, there is ample time for () decay to occur. The r process represents quite the opposite situation. Neutron capture is not interrupted by () decay. 

As a nuclear reaction, the s process is relatively well understood, but the problem lies in identifying an astrophysical site for it and determining the relevant physical parameters, such as neutron flux, mean time separating two neutron captures, and temperature. It has been shown that the most propitious temperatures are those of helium fusion. Added to the fact that the surfaces of certain red giants are rich in s isotopes, such as radioactive technetium and barium, this observation confirms the idea that the s process may be related to helium fusion regions in stars. 

Neutrons needed to develop the s process are essentially produced at temperatures of the order of 100 to 150 million K. 

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The history of lead is almost as ancient as that of tin. In Roman times, lead was formed into pipes that were used for water supplies (hence our word plumbing, derived from the same Latin word, plumbum, that gives us the s Tnbol Pb). Lead is a component of pewter and also was used as a glaze on drinking vessels. White lead, ... 

Jerome O. Nriagu. The Rise and Fall of Leaded Gasoline. The Science of the Total Environment. 92 (1990) 13-28. An authoritative history of leaded gasoline. The source for airplane octane lead industry pays Kehoe s salary one of few environmentally unsafe products forced out of market place one of top 10 chemicals in U.S. Esso slogan compression ratio and valve seat recession Kettering about automobile at crossroads, Europe versus U.S. 90 percent all U.S. gas and 80 percent worldwide autos after 20 years of TEL TEL drove U.S. transport lead removed from Ethyl trade name and Ethyl s control of publications and environment to be monitored by voluntary self-regulation, not legislation. 

Gulson B, Wilson D. 1994. History of Lead Exposure in Children Revealed from Isotopic Analyses of Teeth. Arch Env Health 49(4) 279-283. 

Cumming, G.L., Kyle, J.R., Sangster, D.F. 1990. Pine Point A case history of lead isotopic homogeneity in a Mississippi Valley-type district. Economic Geology, 85, 133-144. 

Warren C (2000) Brush with Death A Social History of Lead Poisoning. Baltimore, MD Johns Hopkins University Press. 

The emergence of this "accidental" approach to drug discovery has its origins in early history with traditional natural herbal remedies that were passed from generation to generation in local communities or tribes. In fact, the early history of lead discovery is all about natural products and herbal remedies, the use of which dates back thousands of years. 

Markowitz and Rosner, Deceit and Denial, pp. 18—19 Kovarik, Context of Technological Alternatives C. Warren, Brush with Death A Social History of Lead Poisoning (Johns Hopkins University Press, Baltimore, 2.000), pp. 120-123. 

Lin-fu JS Modern history of lead poisoning a century of discovery and rediscovery, in Human Lead Exposure. Edited by Needleman HL. Boca Raton, FL, CRC Press,... 

If the history of lead-acid batteries is an indicator, the performance of a super capacitor and storage battery combination will likely be improved further as additional materials and designs are developed and field experience with the HEV and wind energy applications increases. Other sustainable energy systems that operate over a wide range of currents may also benefit from this work. Many types of carbons as well as other materials are being studied. The challenge is to find materials that are low cost and are also compatible with the lead-acid system. 

If you are at risk for soil contamination either because you live near a busy street or industrial source of lead or because you have had lead paint deteriorating on your property or a history of lead arsenate pesticide spraying, you should take precautions, unless and until you have had your soil tested and are told that it is safe. Limit your children s exposure to the soil, and exercise caution regarding any vegetable gardening. 

Publishes "Hour of Lead A Brief History of Lead Poisoning in the United States and the Efforts of the Lead Industry to Delay Regulation. ... 

The history of lead is also inextricably linked with the mining and recovery of silver, which was produced for its value as a currency of trade, as well as a precious metal for the manufacture of jewellery and artefacts. Because of lead s association with silver and its potential use for degrading silver coinage, lead mining and smelting operations were often closely controlled by the application of strict laws. 

The history of lead is as old as the recorded history of mankind. Its use as a valuable material in society has been equally long and varied. In more recent times awareness of lead s toxicity has restricted its widespread use and many older applications have been replaced by newer materials or have been phased out. Today the use of lead is dominated by the automotive lead-acid battery, and a key feature of this application is the ability to achieve a high level of recovery and recycle of scrap batteries. This attribute now makes lead the most recycled metal in use and approaching 60 per cent of the world s supply of lead is provided by recycled metal. Secondary processing and smelting is consequently as important a part of the extractive metallurgical industry as primary extraction from ores and concentrates. 

In 1980, Mushak and Schroeder authored the first report to a U.S. Federal agency that focused exclusively on the science of lead within a multimedia pollutant framework. It was combined with the legislative history of lead and other multimedia pollutants (Mushak and Schroeder, 1980) with reference to effectiveness. This report to the U.S. National Commission on Air Quality was summarized and cited in the Commission s report. To Breathe... 

A Brief Early History of Lead as an Evolving Global Pollutant and Toxicant... 

Principal interest in the early industrial and public health history of lead for this book is in those aspects of lead that allowed lead production and consumption to evolve as a useful and desirable economic enterprise while overshadowing societal concerns about lead s adverse human health and safety aspects in the ensuing centuries and millennia. This intertwined history of lead as an economic commodity of major importance and lead s potential as a widely dispersed environmental contaminant in early and later, industrializing societies guaranteed that the element and its compounds would become a major player in human environmental health in both the workplace and the ambient environment of nonoccupational populations. This chapter deals with lead as a contaminant Chapter 11 considers its early history as a toxic substance. 

Second, the requirement of severe Pb exposures in mothers as necessary for lead reproductive and developmental toxicity is not a tenable premise. As noted in later chapters, embryo- and fetotoxicity is quite a sensitive endpoint in humans and occurs at relatively low systemic lead levels owing to ready transplacental movement of lead early in pregnancy (NAS/NRC, 1993 U.S. ATSDR, 1988 U.S. CDC, 1985, 1991, 2005 U.S. EPA, 1986, 2006). The occupational history of lead in the late nineteenth and early twentieth centuries establishes various adverse reproductive outcomes in pregnant women not themselves demonstrably debilitated by manifest lead poisoning (Legge, 1901 Oliver, 1911 U.S. EPA, 1986, 2006). 

Gulson, B.L., Wilson, D., 1994. History of lead exposure in children revealed from isotopic analyses of teeth. Arch. Environ. Health 49, 279-283. 

Kitman J.L. 2000. The secret history of lead. The Nation 270, March 20. 

Stevenson L.G. 1949. A History of Lead Poisoning. Ph.D. Thesis. The Johns Hopkins University, Baltimore, MD. 

The history of lead regulation outside the United States, particularly in European countries, differs both qualitatively and quantitatively across countries and political systems. A significant part of this differential history traces to the tenure of the problem. Attempts at lead regulation in the United States were largely a twentieth-century effort, particularly in the second half of the century. By contrast, lead control in other political jurisdictions, particularly... 

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