Polypropylene has proven to be the ideal material for the outer shell of the lead acid batteries. Due to its mold-ability and inert properties the material provides a capsule for the functioning components of the lead acid battery and can withstand a variety conditions encountered during its application, such as impact shock resistance, high and low temperatures and acid resistance. Polypropylene has however become of great concern with regards to environmental pollution since it is generally resistant to normal conditions of degradation and can only be properly disposed of by incineration. This factor has encouraged the industry to find ways to regenerate spent polypropylene. A good example of such a process is the recycling of lead acid batteries. This allows not only for the regeneration of lead, but also for the recycling of polypropylene in the manufacturing of battery cases. There are some cost advantages in using recycled polypropylene. However it does have its disadvantages in that the material does start to deteriorate after multiple processes. A common practice amongst battery manufacturers is to add virgin polypropylene to the recycled material in order to ensure performance consistency. The comparative study investigated the use of various ratios of virgin and recycled PP in the manufacturing of lead acid battery cases and their influence on the physical properties and performance of the final material. The degradation of PP was also investigated as the material was subjected to multiple manufacturing processes where the influence of stabilizers was further considered. A common technique of PP analysis such as MFI was shown to be an effective technique to maintain good quality control. The study further showed that it is important that the material grade of PP used in the manufacturing of the battery case and lid is compatible in order to allow for effective heating sealing of the two components. Polypropylene has a waxy surface finish and it is generally difficult to label or write on. Labels tend to fall off in application and make it difficult to maintain a track record of the manufactured batteries with time. This study showed successfully that a laser activated dye can be added to the PP without influencing its color or its performance. This allows for successful labeling of battery cases by various bar coding writers that can trace the battery through its manufacturing process. Lead acid batteries are often operated outside the specified temperature range that is determined by battery manufacturers resulting in premature failure. These failures can occur within the warranty period of the battery and result in illicit claims since the monitoring of the batteries in its application was not possible. A suitable temperature monitoring device was designed that would be incorporated into the vent cap or lid of the battery case. The device contained temperature sensitive indicators that would undergo a permanent color change at specified temperatures thereby giving the battery manufacturer an indication as to the maximum temperature the battery was exposed to.

No description available.

This thesis describes the effects of phosphoric acid on the positive lead dioxide electrode of a lead-acid cell. The aim of this research was to evolve a mechanism for the action of phosphoric acid on the charge (PbSO4→PbO2) and discharge (PbO2→PbSO4) processes. Industrially, phosphoric acid is added to the battery electrolyte because it has certain beneficial effects of preventing formation of 'hard' sulphate and reduction in shedding of active material resulting in improved cycle life. The main disadvantage of phosphoric acid-containing electrolyte is a reduction in capacity of the cell.

No description available.

It is well known that a conventional lead acid cell that is exposed to a partial state of charge capacity cycling (PSoCCC) would experience a build-up of irreversible PbSO4 on the negative electrode. This results into a damaged negative electrode due to excessive PbSO4 formation by the typical visual “Venetian Blinds” effect of the active material. This displays the loss of adhesion of the active material with the electrode’s grids thereby making large sections of the material ineffective and reducing the cells useful capacity during high current applications. The addition of certain graphites to the negative paste mix had proven to be successful to reduce this effect. In the first part of the study, the physical and chemical properties of the various additives that are added to the negative electrode paste mix were comparatively studied. This was done to investigate any significant differences between various suppliers that could possibly influence the electrochemical characteristics of the Pb-acid battery performance. This comparative study was done by using the following analytical techniques; BET surface area, laser diffraction particle size, PXRD, TGA-MS and SEM. The study showed that there were no significant differences between the additives supplied from different suppliers except for some anomalies in the usefulness of techniques such as N2 adsorption to study the BET surface area of BaSO4. In order to reduce the sulphation effect from occurring within the Pb-acid battery a number of adjustments are made to the electrode active material. For example, Pb-acid battery manufacturers make use of an inert polymer based material, known as Polymat, to cover the electrode surfaces as part of their continuous electrode pasting process. It is made from a non woven polyester fiber that is applied to the pasted electrodes during the continuous pasting process. In this study the Polymat pasted electrodes has demonstrated a better physical adhesion of the active material to the grid support thereby maintaining the active material’s physical integrity. This however did not reduce the sulphation effect due to the high rate partial state of capacity cycling (HRPSoCCC) test but reduced the physical damage due to the irreversible active material blistering effect. The study investigated what effect the Polymat on the electrodes has on the III battery’s Cold Cranking Ability (CCA) at -18 degree C, the HRPSoCCC cycling and its active material utilization. The study showed that there was little or no differences in the CCA and HRPSoCCC capabilities of cells made with the Polymat when compared to cells without the Polymat, with significant improvement in active material’s adhesion and integrity to the grid wire. This was confirmed by PXRD and SEM analysis. Negative electrodes were made with four types of graphites (natural, flake, expanded and nano fibre) added to the negative paste mixture in order to reduce the effect of sulphation. The study looked at using statistical design of experiment (DoE) principles to investigate the variables (additives) such as different graphites, BaSO4 and Vanisperse to the negative electrode paste mixture where upon measuring the responses (electrochemical tests) a set of controlled experiments were done to study the extent of the variables interaction, dependency and independency on the cells electrochemical properties. This was especially in relation to the improvement of the battery’s ability to work under HRPSoCCC. The statistical analysis showed that there was a notable significant influence of the amounts of vanisperse, BaSO4 and their respective interactions on a number of electrochemical responses, such as the Peukert constant (n), CCA discharge time, material utilization at different discharge rates and the ability to capacity cycle under the simulated HRPSoCCC testing. The study did not suggest an optimized concentration of the additives, but did give an indication that there was a statistical significant trend in certain electrochemical responses with an interaction between the amounts of the additives BaSO4 and Vanisperse. The study also showed that the addition of a small amount of Nano carbon can significantly change the observed crystal morphology of the negative active material and that an improvement in the number of capacity cycles can be achieved during the HRPSoCCC test when compared to the other types of graphite additives.

Ratio recording methods in mass spectrometry have hitherto been successfully used in analyses involving only a few of the lighter elements. In all these cases a great improvement in precision has resulted. This thesis describes a means whereby grid ratio recording can be extended to the precise measurement of complex spectra in the high mass range. In particular, lead isotope studies in geophysics provide a great and continuing need for increased analytical precision. The project has involved the construction of a complete mass spectrometer which incorporates two main features which have not been used before in mass spectrometry. The first of these is a scanning mechanism which moves the collector across the stationary ion beams. It is this innovation which has made possible the development of grid ratio recording. Since the total ion beam is stationary, variations in its intensity during the scanning process can be monitored accurately. A servo-divider system is arranged to make the measuring system Insensitive to variations in the total ion beam by recording the individual ion beam currents as fraction of the total Ion beam. The ratio system will effectively reduce large variations in the total Ion beam due to changes in source conditions by a factor of fifteen. Smaller variations are reduced to below the noise level existing in the recording system itself. The second principle which is believed to be new to mass spectrometry is the method by which the results of an analysis are presented by the instrument. An expanded scale system of recording has been developed whereby the amplitude of an ion current is presented as a digit on a counting tube, with the remainder displayed as a peak on a chart recorder. It is demonstrated that the expanded scale arrangement will record a known signal with a standard deviation of less than 0.02%. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

On the basis of data published prior to 1960, two basic lead isotope models - the isochron model and the primary lead model - were postulated to fit those crustal leads that have had the simplest history. The present writer's analyses of samples from Southern Finland, and the results of other research workers, now indicate that the primary lead model more adequately describes these leads, and that primary "isochrons" are either very short, or else non-existent. Lead in conformable deposits and in ultrabasic sulfides were postulated by R.L. Stanton to be examples of primary lead. Analyses of samples from several massive lead-zinc conformable deposits have indicated that the leads of many of these deposits possess primary lead characteristics. The present thesis describes a technique devised to prepare tetramethyllead from the conformable chalcopyrite deposits and ultrabasic sulfides and describes some initial results. This is a free radical technique, involving the reaction of methyl radicals with a lead mirror evaporated out of a sulfide. It appears to be capable of preparing tetramethyllead from samples containing one to two orders of magnitude less lead than previously reported for such a technique. Unfortunately, the full extent of the method cannot be utilized with present gas source mass spectrometer facilities, and only fair precision (0.4%) is possible at 10 ppm. lead. Samples from the conformable chalcopyrite deposits of Mt. Isa were analysed. The lead isotope ratios were found to be significantly different from those of the massive lead-zinc deposits. The results, interpreted with other lead and sulfur isotope data, suggest that these deposits could be the result of metal-bearing solutions entering a partially enclosed bay. Initial results for two ultrabasic deposits suggest that the lead in the sulfides is not necessarily primary; for example, that in two Stillwater ultrabasic complex samples appears to be the result of three stages of development. Hence, both the present lead isotope analyses, and those reported earlier by Ostic (1963) indicate that Stanton's geological criteria, while good, are not completely adequate for identifying primary leads. It is here suggested that sulfur isotope analyses might indicate which of these samples have been contaminated by crustal leads. During the investigation of the gas source mass spectrometric analyses of small tetramethyllead samples, lead isotope fractionation was observed. This occured with molecular flow into the mass spectrometer. Lead isotope fractionation has not been reported previously, and has some interesting geophysical implications. A preliminary study suggests that such fractionation in nature is likely to be rare, except possibly in biological processes in the sea. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

The isotopic constitution of lead became important in geophysics as the lead-uranium and lead-thorium methods of absolute geological age determination were established. Interest in the isotopic abundances of common lead in lead minerals was a natural development. The interpretations of observed variations in lead isotope ratios has been more simple than had been expected twenty years ago when the first measurements of this kind were made by A. 0. Nier, and results have been obtained that are of very great importance to geophysics. Consequently this field is now expanding very rapidly. Many interpretations now being made are limited by the available precision of the measurements, which is of the order of several tenths of a per cent. A mass spectrometer laboratory was set up in the Department of Physics at The University of British Columbia, and a mass spectrometer capable of measuring heavy elements with high precision was designed and constructed. It is a 90 degree sector, 12 inch radius, direction focusing instrument with a copper tube and using a modified Nier-type gas source. It is essentially of orthodox design, but special attention was given to try to eliminate small sources of error. To establish more stable source conditions, an exceptionally stable filament emission control was constructed and purified lead tetramethyl samples were used. The ion beam was measured with a servo-voltmeter of original design that is capable of a high precision. Readings can be made from a calibrated dial on the voltmeter eliminating sources of error in the usual chart recorder. Tests have shown that the improvement in precision warrants this step. This mass spectrometer is believed to be the first to use extensively transistorized circuits. Error was reduced further by comparing each sample measured with a standard within reasonably short intervals of time (about twenty minutes). Three comparisons were made to loop two samples with the standard, and the looping error was determined and distributed around the loop. The analyses obtained in this way were compared with existing analyses from other laboratories, and an improvement in precision between a factor of five and a factor of ten seems to have been obtained. To demonstrate the precision obtainable with this mass spectrometer and with the improvement in operating techniques, analyses were made on the isotopic composition of leads from Broken Hill and Mount Isa, Australia. It was previously known that the leads are very similar in composition at both localities. From these new measurements it was established that the Broken Hill and Mount Isa deposits contain lead of distinctly different isotopic composition. In both deposits the isotope ratios were found less variable than could be inferred from previous measurements. A fine structure was found in the isotope ratios in both localities. These small variations indicate contaminations due to radiogenic leads. Values of the thorium/uranium ratios of the source of contamination were estimated. The precision of analyses made it possible to determine an age difference between the Mount Isa and Broken Hill deposits of 40 million years. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

Data of good quality is necessary to further the study of rock lead isotopic interpretations. An internal standard (double-spike) was employed to correct for fractionation accompanying the single filament analyses, and lead isotope ratios with a standard deviation of 0.15% were obtained. Lead sulphide mounted on tantalum was employed for the lead analyses. Discrimination in the analyses using tantalum filaments was consistent with the theoretical fractionation laws. This was not found to be the case for rhenium. Lead and uranium analyses from the Vogt-Hobbs area near Lake Timagami, Ontario and from the Rice Lake-Beresford Lake Area, Manitoba revealed variations from a simple two stage model that could not be accounted for by experimental error. Interpretation of the data yields a three stage history for both of these regions, marked by major events at approximately 3400 and 2600 my ago. This earlier crustal history is supported by ore lead data from the vicinity. Both of the suites have a lower average value of (U238/Pb204) for the second stage, of their three stage history, than is characteristic of the source of single stage leads. Variations from closed system behaviour for the Ontario samples is attributed to lead remobilization at the time of the Grenville event. Remobilization of the lead tends to mask the 2600 my old event. The Vogt-Hobbs area is characterized by more acidic igneous rocks and more radiogenic lead than the Rice Lake-Beresford Lake area. These differences are thought to represent the environment 2600 my ago or earlier. The Manitouwadge lead analysed by Ostic resembles the lead - 2600 my ago in the Rice Lake-Beresford Lake rock samples. The Rice Lake-Beresford Lake rock samples are shown according to the interpretation presented, to have had a crustal history prior to 2600 my ago. This lends weight to arguments that exclude Manitouwadge from the class of single stage leads used in calculations of the age of the earth. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The atomic spectra of Thallium were excited and photographed in the spectral region from 340 to 9000 Å , using both an electrodeless discharge and a spark-in-Helium as light sources. The single electron Rydberg series have been extended in TI III. The ionization potential of TI III and Pb IV was determined from hydrogenic terms and found to be 240773 ± 5 cm⁻¹ and 342438 ± 5 cm⁻¹ respectively. The dipole polarizability of TI III was found to be 2.53 ± .02 a³₀ and of Pb IV 4.37 ± .04 a³₀. Using a line list previously obtained in this laboratory, terms belonging to three electron configuration were established in TI III and Pb IV. The 5d⁹ ns series was extended in TI IV and an ionization potential of 412500 ± 300 cm⁻¹ arrived at. In TI IV and Pb V the two electron configurations 5d⁹ 6d, 5d⁹ 5f, 5d⁹ 7p and 5d⁸ 6s² were partially established while a number of terms belonging to the complex 5d⁸ 6s6p configuration could be identified as well. The analysis of TI II was extended by completing the 5d¹º 6p² configuration and identifying a number of odd and even parity terms above the first ionization limit. These were tentatively assigned to the 5d¹º 6p7p, 5d⁹ 6s² 7s, 5d⁹ 6s² 6d, 5d⁹6s6p² and the 5d¹º6p7s configurations. The number of classified TI III lines, involved in this extension of the term analysis, has increased from 247 to 579. In the TI IV spectrum the increase in classified lines has been from 35 to 308 lines. In lead spectra the increase in Pb IV has been from 134 lines to 460, and in Pb V the corresponding increase is from 200 to 303 lines. / Science, Faculty of / Physics and Astronomy, Department of / Graduate