Thesis (Ph. D.)--Columbia University, 1936. / Vita. Bibliography: p. 44-[45].

Thesis (Ph. D.)--University of Wisconsin--Madison, 1958. / Typescript. Vita. Appendix: Analysis of phenobarbital in pharmaceuticals by argentimetric potentiometric titration / By Jerome Irwin Bodin. Reprinted from Journal of the American Pharmaceutical Association, scientific edition, vol. XLV, no. 3 (Mar. 1956), p. [185]-187. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 138-139).

Thesis (PH. D.)--University of Michigan, 1928.

Made available in DSpace on 2014-10-09T12:53:11Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:02Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Made available in DSpace on 2014-10-09T12:53:11Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:02Z (GMT). No. of bitstreams: 0 / A avaliação metrológica da incerteza da medição, apesar de estar normalizada internacionalmente (ISO-GUM, 1995) desde a metade dos anos 90, só agora está se popularizando nas indústrias, nas escolas técnicas e de engenharia. Em algumas áreas, como na metrologia dimensional, está avançada e em outras, como na medição de variáveis de processos industriais tais como vazão, pressão e temperatura, ainda está numa fase intermediara. Um dos principais entraves para essa popularização é a falta de padronização da nomenclatura nas especificações técnicas dos instrumentos de medição, onde se declara a incerteza, por exemplo, de 1% de ?acurácia? sem definir se é percentual da leitura, da faixa calibrada ou da faixa máxima. Ou ainda, sem definir se a probabilidade de abrangência é 68, 95 ou 99,7%. Esse trabalho entra nesse cenário com a pretensão de clarificar e simplificar esses conceitos, começando pelo histórico da evolução do pensamento que transformou a incerteza numa variável quantitativa com sua avaliação efetuada de uma maneira padronizada e internacionalmente aceita. Em seguida é feita uma descrição conceitual sucinta do método ISO-GUM e também é desvendado o intrincado jogo de palavras e fórmulas das declarações de incertezas dos fabricantes de instrumentos de medição. Com o domínio desses conceitos, partimos para efetuar dois exemplos numéricos de avaliação metrológica de incertezas na medição de vazão, usando um conjuntos de fórmulas semelhantes Ás publicadas por renomados fabricantes de instrumentos de medição. No primeiro exemplo usando a medição de vazão por pressão diferencial com placa de orifício e no segundo usando um medidor volumétrico, nos quais são identificadas e quantificadas todas as potenciais fontes de incerteza. A visualização e a analise é feita através de gráficos e planilhas em Excel. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Magister Scientiae Dentium - MSc(Dent) / Objectives: To determine the total volumetric change and the relative speed of shrinkage of bulk fill flowable composites during polymerization. Background: The volumetric change that occur during the polymerization of dental composite restorations are considered to be one of the most significant contributing factors when considering the failure in composite restorations. Volumetric shrinkage of more than 2% is considered to be enough to result in the occurrence of secondary caries resulting in fracture of restorations and failure in the adhesive layer of a resin restoration. The total volumetric change of dental resins can be attributed to three main factors: Firstly, the polymerization reaction that results in the formation of a polymer chain. Secondly, the increase of the exothermic thermal effects produced by the polymerization reaction and thirdly, light irradiance energy that is transferred to the dental resin. Materials and Methods: A specially designed electronic mercury dilatometer at the UWC Oral and Dental Research Institute was used to determine the volumetric change. The light intensity was set at 500mW/cm2. The mercury dilatometer measured the volumetric change every 0.5 seconds during the 35 second irradiation exposure time. The materials tested were Z250 as the control and four bulk fill flowable composites. The volume of voids within the cured material samples were assessed with a Micro-3D ct reconstruction (General Electric Phoenix). Results: The sequence of total volumetric change from least to most were: Z250 < Filtek bulk fill < Xtra-Base bulk fill < SDR < Venus bulk fill. The speed/rate of shrinkage of the bulk fill flowable composites were faster than that of Z250, while the 2 bulk fill flowables with the highest shrinkage speed (SDR and Venus) also had the highest total volumetric change. Of the different materials tested the volumetric change of Z250 (1.13%) was the lowest and significantly less (p<0.05) than that of SDR (1.56%) and Venus (1.72%). The Kruskal-Wallis multiple comparison test indicated that the material with the highest filler content (Z250) also showed the lowest shrinkage (1.13%) but this effect of the filler content could not be seen in the bulk fill flowable composites. The volume of the voids within the test specimens were determined and were represented as a percentage of the cured volume (49.087mm³). Venus had the largest percentage of voids (1.18%) in the test specimen (specimen volume: 49.087mm³), followed by Z250 with 0,5248%, Xtra base with 0,00015%, SDR with 0,00059% and Filtek bulk fill with 0,00069%. Conclusions: The volumetric changes and rate of shrinkage were higher for all 4 bulk fill flowable composites than for Z250. Furthermore, the speed of shrinkage based on the polymerization reaction differed between the materials. SDR and Venus flowables had the fastest rate and highest volumetric change. The small percentage of voids within the materials seemed not to have affected the volumetric change negatively. Clinical significance: The manufacturers of bulk fill flowable composites advocate filling layers of 4mm. However, because of the high shrinkage values found in this study the use of the standard 2mm layer increments is recommended.

Please read the abstract in the section 00front of this document. / Dissertation (MSc (Chemistry))--University of Pretoria, 2007. / Chemistry / unrestricted

Interest in the automation of titration arise from the fact that many acid-base titrations in the process industries rely on manual titration which is time consuming. Miniaturization of these titration processes becomes attractive because of the reduced reagent consumption. These industries must produce higher quality products economically and in a friendly environment. Due to its ease of automation, ability to handle concentrated solutions and simplicity, the application of sequential injection titration is an ideal tool in process effluent streams, food industries, beverage industries and production plants. The sequential injection titration system was optimised with respect to all instrumental parameters of the system and applied for acid-base titrations. The results obtained showed high reliability and reproducibility. The system is fully computerised, inexpensive and suitable for on-line monitoring. / Dissertation (MSc (Chemistry))--University of Pretoria, 2006. / Chemistry / unrestricted

Analysis is a very important branch of chemistry, for it is such a practical part of the science. Analysis is itself divided into two parts. Qualitative analysis discovers what things are present in the material in question. Quantitative analysis then determines how much of each ingredient is present. This thesis considers a limited section of quantitative analysis. This thesis deals with the use of iodine in volumetric analysis, which is called either iodimetry or iodometry. In this type of analysis, the iodine is used in solution and reacts with some other material, also in solution, and takes up electrons. That is, the iodine is reduced, or electronized. In the second volume of the work referred to above the thirteenth chapter of some eighty pages is devoted to "Practical Methods of Iodometry."2 There are obviously many applications of this method. Our study was confined to the reaction of iodine with arsenic trioxide, concerning which Kolthoff says: "Standardization against arsenious oxide has proved to be best."3

The analytical chemist is ever eager to improve and expedite present analytical methods.. In the past ten years considerable interest .has been elicited in the field of high frequency oscillators and their application to analytical chemistry. One of the main reasons for this interest is the uniqueness of the apparatus. No direct contact is made between the measuring instrument and the solution. Credit tor this interest must be given primarily to Jensen and Parrack of Texas A & M University. Their article in 1946 described a simple tuned plate-tuned grid electronic oscillator, operating in the high frequency range. A solution was exposed to t he electromagnetic field or the plate coil. During the titration the electrical characteristics of the solution changed. These changes were reflected in measurements of the electrical constants of the oscillator. Upon analysis the constants clearly showed the end point and yet no physical contact had been made with t he solution. Since the instrument of Jensen and Parraok many modifications have appeared and even entirely new instruments. However they still keep the one common feature: no contact with the solution. In addition to titrations, the instrument has been used to advantage in many other fields of analytical chemistry. After ten years it has clearly established itself as a valuable tool rather than just a laboratory curiosity. The object of this present research was to build an original instrument and test its effectiveness in as many fields as possible.