Download or read book ETUDE ET OPTIMISATION DE LA LIMITE DE DETECTION EN SPECTROPHOTOMETRIE D ABSORPTION ATOMIQUE CONTRIBUTION A LA COMPREHENSION DES MECANISMES EN MILIEU EAUX NATURELLES written by HELENE.. LE GARREC and published by . This book was released on 1997 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: A la limite de détection définie par l'impact est le meilleur paramètre d'optimisation en spectroscopie d'absorption atomique à atomisation électrothermique (SAAET) quand il s'agit d'atteindre les meilleures limites de quantification, mais les 11 mesures nécessaires à sa détermination sont matériellement impossibles à effectuer systématiquement. Un calcul statistique simple et une étude expérimentale sur le bruit affectant les signaux d'atomisation blancs intègres ont permis de montrer les conséquences de l'intégration sur les limites de détection qu'il est possible d'annoncer et de définir une nouvelle grandeur d'optimisation, la limite de détection estimée ou DLE, calculée sur une seule atomisation. Cette grandeur est très proche de la limite de détection instrumentale (IUPAC) quand un procédé d’affectations correctes du zéro est employé. L’introduction de la contribution d'un signal non-spécifique à l'expression de la DLE permet de traiter également le cas des échantillons naturels. Une démarche d'optimisation de la méthode, fondée sur le suivi de la DLE a l'aide de matrices d-optimales, a pu ainsi être proposée en considérant indépendamment deux catégories de paramètres. Pour les facteurs spectroscopiques, cette méthode d'optimisation est appliquée au cadmium, manganèse, cuivre et étain et pour les facteurs électrothermiques, a la détermination du cadmium, du manganèse et du cuivre dans un milieu naturel complexe, l'eau de mer. L’abaissement des limites de quantification en saaet passe aussi par une meilleure connaissance de la chimie complexe se produisant à haute température dans l'atomiseur. Des conditions expérimentales particulières sont proposées pour permettre des études cinétiques de signaux génères en présence de matrices minérales. Ces conditions, testées pour le manganèse et le cuivre en présence de quelques matrices nitrate et sulfate, ont conduit a la proposition de schémas raisonnables de réactions d'atomisation et de décomposition des matrices.
Download or read book CONTRIBUTION A L ETUDE DE DOSAGES PAR SPECTROPHOTOMETRIE D ABSORPTION ATOMIQUE written by AGNES.. EXANDIER and published by . This book was released on 1984 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book D termination de traces d l ments en spectrophotom trie d absorption atomique written by Bernard Hircq and published by . This book was released on 1976 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: RAPPEL THEORIQUE SUR LA RAIE SPECTRALE ET LE COEFFICIENT D'ABSORPTION. L'ETUDE EST MENEE EN PARTANT DE QUELQUES MICROLITRES DE SOLUTION DE L'ELEMENT A DOSER DEPOSES SUR FILAMENT METALLIQUE (RHENIUM) OU DE GRAPHITE: LIMITES DE SENSIBILITE DANS LES CONDITIONS OPTIMALES POUR AG, AS, AU, HG, SE, SN, PB, CD, ZN, DANS LE CAS DU FILAMENT METALLIQUE. APPLICATION DU FILAMENT DE GRAPHITE AU DOSAGE D'IMPURETES DANS L'URANIUM. CET EXAMEN PERMET DE CONSTATER LES EFFETS DE L'ATOMISATION: L'ABSORPTION D'UN RAYONNEMENT PAR UN "NUAGE ATOMIQUE". ON ETUDIE CE "NUAGE ATOMIQUE" QUANT A SA FORME ET A LA REPARTITION DES CONCENTRATIONS, A L'AIDE D'UN SPECTROPHOTOMETRE, EN FONCTION DES PARAMETRES EXPERIMENTAUX. APPLICATION A LA DETERMINATION DE GRANDEURS PHYSIQUES. ETUDE DU DEPOT EFFECTUE SUR LE GENERATEUR D'ATOMES ET LA TRANSFORMATION D'UNE MATRICE (CAS DE U) AU COURS DES CYCLES THERMIQUES IMPOSES AU SUPPORT D'ATOMISATION
Download or read book Arsenic in Drinking Water written by National Research Council and published by National Academies Press. This book was released on 2001-11-26 with total page 241 pages. Available in PDF, EPUB and Kindle. Book excerpt: Having safe drinking water is important to all Americans. The Environmental Protection Agency's decision in the summer of 2001 to delay implementing a new, more stringent standard for the maximum allowable level for arsenic in drinking water generated a great deal of criticism and controversy. Ultimately at issue were newer data on arsenic beyond those that had been examined in a 1999 National Research Council report. EPA asked the National Research Council for an evaluation of the new data available. The committee's analyses and conclusions are presented in Arsenic in Drinking Water: 2001 Update. New epidemiological studies are critically evaluated, as are new experimental data that provide information on how and at what level arsenic in drinking water can lead to cancer. The report's findings are consistent with those of the 1999 report that found high risks of cancer at the previous federal standard of 50 parts per billion. In fact, the new report concludes that men and women who consume water containing 3 parts per billion of arsenic daily have about a 1 in 1,000 increased risk of developing bladder or lung cancer during their lifetime.
Download or read book Gas cooled Nuclear Reactors written by France. Commissariat à l'énergie atomique and published by . This book was released on 2006 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Total Diet Studies written by Gerald G. Moy and published by Springer. This book was released on 2016-08-23 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unless a food is grossly contaminated, consumers are unable to detect through sight or smell the presence of low levels of toxic chemicals in their foods. Furthermore, the toxic effects of exposure to low levels of chemicals are often manifested slowly, sometimes for decades, as in the case of cancer or organ failure. As a result, safeguarding food from such hazards requires the constant monitoring of the food supply using sophisticated laboratory analysis. While the food industry bears the primary responsibility for assuring the safety of its products, the overall protection of people’s diets from chemical hazards must be considered one of the most important public health functions of any government. Unfortunately, many countries do not have sufficient capability and capacity to monitor the exposure of their populations to many potentially toxic chemicals that could be present in food and drinking water. Without such monitoring, public health authorities in many countries are not able to identify and respond to problems posed by toxic chemicals, which may harm their population and undermine consumer confidence in the safety of the food supply. From a trade perspective, those countries that cannot demonstrate that the food they produce is free of potentially hazardous chemicals will be greatly disadvantaged or even subject to sanctions in the international marketplace. The goal of a total diet study (TDS) is to provide basic information on the levels and trends of exposure to chemicals in foods as consumed by the population. In other words, foods are processed and prepared as typical for a country before they are analyzed in order to better represent actual dietary intakes. Total diet studies have been used to assess the safe use of agricultural chemicals (e.g., pesticides, antibiotics), food additives (e.g., preservatives, sweetening agents), environmental contaminants (e.g., lead, mercury, arsenic, cadmium, PCBs, dioxins), processing contaminants (e.g., acrylamide, polycyclic aromatic hydrocarbons, chloropropanols), and natural contaminants (e.g., aflatoxin, patulin, other mycotoxins) by determining whether dietary exposure to these chemicals are within acceptable limits. Total diet studies can also be applied to certain nutrients where the goal is to assure intakes are not only below safe upper limits, but also above levels deemed necessary to maintain good health. International and national organizations, such as the World Health Organization, the European Food Safety Agency and the US Food and Drug Administration recognize the TDS approach as one of the most cost-effective means of protecting consumers from chemicals in food, for providing essential information for managing food safety, including food standards, and for setting priorities for further investment and study. Total Diet Studies introduces the TDS concept to a wider audience and presents the various steps in the planning and implementation of a TDS. It illustrates how TDSs are being used to protect public health from chemicals in the food supply in many developed and developing countries. The book also examines some of the applications of TDSs to specific chemicals, including contaminants and nutrients.
Download or read book Scientific Basis for Nuclear Waste Management XXII Volume 556 written by David J. Wronkiewicz and published by . This book was released on 1999-11-24 with total page 1370 pages. Available in PDF, EPUB and Kindle. Book excerpt: Safe and effective management of nuclear waste provides a broad range of challenges for materials science. Waste processing, waste form and engineered barrier properties, interactions between engineered and geological systems, radiation effects, chemistry and transport of waste species, and long-term predictions of repository performance are just some of the scientific problems facing modern society. This book, the 22nd in a very successful series from MRS, offers an international and inter-disciplinary perspective on the issues, and features developments in both fundamental and applied areas. Topics include: development and characterization of ceramic waste forms; ceramic waste form corrosion; glass waste form processing; glass formulation, properties and structure; glass waste form corrosion; spent nuclear fuel; performance assessment; repository backfill; flow and transport; natural analogues; container corrosion; metal waste form corrosion; radionuclide speciation and solubility; radionuclide sorption; microbial effects; radiation effects; cement waste forms and waste treatment.
Download or read book Model Cellulosic Surfaces written by Maren Roman and published by OUP USA. This book was released on 2010-04-08 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an overview of the different methods of model cellulosic surface preparation and presents recent studies on the properties of these surfaces. The topics covered are considered relatively new and would serve as the launch pad for further research in this area.
Download or read book From Microphysics to Macrophysics written by Roger Balian and published by Springer Science & Business Media. This book was released on 2007-06-26 with total page 626 pages. Available in PDF, EPUB and Kindle. Book excerpt: This popular, often cited text returns in a softcover edition to provide a thorough introduction to statistical physics and thermodynamics, and to exhibit the universal chain of ideas leading from the laws of microphysics to the macroscopic behaviour of matter. A wide range of applications illustrates the concepts, and many exercises reinforce understanding. Volume II applies statistical methods to systems governed by quantum effects, in particular to solid state physics, explaining properties due to the crystal structure or to the lattice excitations or to the electrons. The last chapters are devoted to non-equilibrium processes and to kinetic equations, with many applications included.
Download or read book Biotechnology and Sustainable Development written by Ismail Serageldin and published by CABI. This book was released on 2003 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on the first scientific conference convened at the Library of Alexandria, 'Biotechnology and Sustainable Development: Voices of the South and North', which was held in Alexandria, Egypt, in March 2002, this book contains overviews of agriculture, health, ethics and the environment. It discusses how dramatic improvements in food security, health, and lifestyle could accrue to the poor people of developing countries through the applications of new technologies.
Download or read book Applied Mineralogy in the Mining Industry written by W. Petruk and published by Elsevier. This book was released on 2000-11-29 with total page 287 pages. Available in PDF, EPUB and Kindle. Book excerpt: Techniques of performing applied mineralogy investigations, and applications and capabilities of recently developed instruments for measuring mineral properties are explored in this book intended for practicing applied mineralogists, students in mineralogy and metallurgy, and mineral processing engineers. The benefits of applied mineralogy are presented by using in-depth applied mineralogy studies on base metal ores, gold ores, porphyry copper ores, iron ores and industrial minerals as examples. The chapter on base metal ores includes a discussion on the effects of liberation, particle sizes and surfaces coatings of Pb, Cu, Fe, Ca and So4- on the recoveries of sphalerite, galena and chalcopyrite. The chapter on gold discusses various methods of determining the quantities of gold in different minerals, including 'invisible' gold in pyrite and arsenopyrite, so that a balance of the distribution of gold among the minerals can be calculated. This book also discusses the roles of pyrite, oxygen, moisture and bacterial (thiobacillus ferrooxidans) on reactions that produce acidic drainage from tailings piles, and summarizes currently used and proposed methods of remediation of acidic drainage.
Download or read book Four Laws That Drive the Universe written by Peter Atkins and published by OUP Oxford. This book was released on 2007-09-06 with total page 142 pages. Available in PDF, EPUB and Kindle. Book excerpt: The laws of thermodynamics drive everything that happens in the universe. From the sudden expansion of a cloud of gas to the cooling of hot metal, and from the unfurling of a leaf to the course of life itself - everything is directed and constrained by four simple laws. They establish fundamental concepts such as temperature and heat, and reveal the arrow of time and even the nature of energy itself. Peter Atkins' powerful and compelling introduction explains what the laws are and how they work, using accessible language and virtually no mathematics. Guiding the reader from the Zeroth Law to the Third Law, he introduces the fascinating concept of entropy, and how it not only explains why your desk tends to get messier, but also how its unstoppable rise constitutes the engine of the universe.
Download or read book Fluorine Magnetic Resonance Imaging written by Ulrich Flogel and published by CRC Press. This book was released on 2016-10-26 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past decade, fluorine (19F) magnetic resonance imaging (MRI) has garnered significant scientific interest in the biomedical research community owing to the unique properties of fluorinated materials and the 19F nucleus. Fluorine has an intrinsically sensitive nucleus for MRI. There is negligible endogenous 19F in the body and thus there is no background signal. Fluorine-containing compounds are ideal tracer labels for a wide variety of MRI applications. Moreover, the chemical shift and nuclear relaxation rate can be made responsive to physiology via creative molecular design. This book is an interdisciplinary compendium that details cutting-edge science and medical research in the emerging field of 19F MRI. Edited by Ulrich Flögel and Eric Ahrens, two prominent MRI researchers, this book will appeal to investigators involved in MRI, biomedicine, immunology, pharmacology, probe chemistry, and imaging physics.
Download or read book Flexoelectricity in Liquid Crystals written by Agnes Buka and published by World Scientific. This book was released on 2013 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.
Download or read book Scientific Basis for Nuclear Waste Management XXIII Volume 608 written by Robert W. Smith and published by . This book was released on 2000-10-09 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt: This long-standing symposia series has become the premier, international forum for scientific and engineering issues related to all levels and types of radioactive wastes and their management. Topics include: fuel cladding and spent nuclear fuel; container fabrication and corrosion; performance assessment; repository performance; radionuclide sorption and transport; cement-based materials and waste containment; corrosion of ceramic wasteforms; structure and characterization of ceramics; radiation effects; natural analogs; wasteform characterization and processing; and corrosion and characterization of glass wasteforms.
Download or read book Applied Reactor Physics written by Alain Hébert and published by Presses inter Polytechnique. This book was released on 2009 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Last Billion Years written by Atlantic Geoscience Society and published by Nimbus Publishing (CN). This book was released on 2001 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is about the history of the rocks and fossils of the Maritime Provinces of Canada (New Brunswick, Nova Scotia and PEI) over the last billion years. The book is beautifully illustrated in full colour, with original paintings of ancient vistas, over 150 photographs, and crisp explanatory diagrams and sketches.
