M.Sc. / Emulsions are not widely used in industry for wear-metal-in-oil determinations and this study was undertaken in order to evaluate such a possibility. The use of emulsified standards was compared to aqueous standards for the calibration of an emulsified used lubricating oil sample. The traditionally used methods of ashing in a muffle furnace and dilution with the organic solvent, xylene were also evaluated in comparison with the emulsion methodology. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used for the wear-metal-in-oil analysis. The performance characteristics of each method were compared for the following metals: AI, Cr, Cu, Fe, Ni, and Pb. The used oil sample and emulsified standards were acid treated and emulsified in water {1% wlw) using tetralin as solvent and triton X-100 as surfactant. This evaluation included the calibration characteristics, precision and accuracy obtained, as well as the results of recovery studies. The emulsification method was found to be comparable to the ashing and dilution methods in terms of calibration and only Cr, Cu, Fe and Pb concentrations were found. The precision of the emulsification method was found, in general, to be close to or less than 2% RSD. The used oil matrix also contained leaked petroleum from a problem car engine. An accurate determination of lead was consequently impossible since the high lead content led to sedimentation. The use of the internal standard, indium, was evaluated for its effectiveness in correcting possible matrix effects that were evident from the results obtained in the recovery studies. The recovery studies showed the Cr and Pb determinations to be adversely affected by internal standardization. An alternative approach for matrix effect correction, the common analyte internal standardization (CAIS) method was also investigated. This method held promise for allowing the use of aqueous standards, instead of oil or emulsion standards, for the calibration of the emulsified oil samples. Three different applications of the CAIS technique were investigated and all proved unsuccessful.

Due to the fact that only comparative results were sought, the investigation was greatly simplified. On a comparative basis, the effects of external influences were largely eliminated from positions of vital importance and the use of an elaborate test, circuit was unnecessary. The equipment consisted of a high-voltage test transformer which supplied the test voltage; an induction regulator, auto transformer and generator field rheostats for voltage control; overload relay and aircore inductances for circuit protection; motor-generator set for a source of 60 cycle alternating voltage. The electrodes were circular, square edge brass discs. Specimens were immersed in lubricating oil for periods up to 40 hours and then tested for puncture strength. Following this, specimens were immersed for one hour and 24 hours and each of the two groups tested at intervals of time up to 720 hours. In each test the voltage was raised in steps of 200 volts, starting at 1000 volts. The puncture strength of the untreated paper was determined by testing a sufficient number of specimens over a period of days. The results obtained indicated no immediate deleterious effects of lubricating oil on paper. On the contrary, there was an improvement in puncture strength, accounted for by the fact that the relatively low voltages-used did not make ionization a serious factor. The results of tho long-time tests were unsatisfactory, as explained previously. However, they did permit the conclusion that deterioration of paper impregnated with lubricating oil would become apparent much sooner than if insulating oil were used. Oxidation, although probably existing, was apparently too slow to affect the results. / Master of Science

The original intention regarding the Reynolds’ Number Apparatus was to design, construct, and operate extensively the experimental machinery. The extensive operation of the apparatus, however, would entail not only the investigation of the effects of various conditions on the Reynolds’ number of liquids, but also the effects of laminar and turbulent flow on the heat transferred from the liquid to the pipe walls. It would also be possible to use the apparatus to determine the friction factors of various diameter pipes. Any one of the above subjects contains enough material for a thesis. It was therefore decided to limit the scope of this investigation to the design, construction, and calibration of the apparatus. In view of the extremely slow delivery of equipment and the many delays encountered during the construction, this was indeed a wise decision. It may therefore be stated that the purpose of this report is to present to the reader the Reynolds’ Number Apparatus and to acquaint him with its design, construction, calibration, and experimental possibilities. Although only enough test runs will be made to calibrate the instruments required to determine the Reynolds’ number of a given oil at one temperature, it is the author’s belief that this report will serve as an adequate guide to the construction of similar apparatuses and will stimulate others to a more extensive investigation of the experimental possibilities. / Master of Science

The object of this investigation was to determine the transfer coefficients based on a “no loss” material balance, Viscosity Gravity Constant for each extraction and the contact area in conjunction with the material balance when a cylinder stock out of midcontinent oil was subjected to furfural refining in a one-inch in nominal diameter pyrex glass spray column using various ratios of furfural to oil. The oil was passed in tiny drops through the 9.75 feet high column countercurrent to the furfural flow which was down through the column. The average number of drops formed and the time of contact with the solvent was determined. From these values the average contact area in square feet at any moment was calculated. Two runs were made at high ratios of furfural to oil, and in these runs, no area of contact was determined. The column extractions were carried out at 75 ± 3°F. In order to determine the equilibrium values necessary for these calculations, batch extractions using the same ratio of solvent to oil were carried out at 230°F—at which temperature the furfural and the oil were miscible. The ratios of furfural to oil used were 2.35, 3.00, 3.53, 5.20, 9.24 and 14.20. The values of the transfer coefficient based on the “no loss” material balance varied from 0.0427 to 4.59 lbs./hr./cu.ft. of column volume/unit C as the ratio was increased. The values of the transfer coefficients based on the Viscosity Gravity Constant varied from 0.0520 to 6.28 lbs./hr./cu.ft. of column volume/unit C as the ratio was increased. The values of the transfer coefficient was based on the “no loss” material balance and the calculated contact area varied from 0.390 to 1.168 as the ratio was increased. The resultant values of the H.T.U.’s based on the three methods of calculation were good checks for the first two ratios and fair checks for the next two highest. For the ratio of 2.35:1.0 the H.T.U. based on the “no loss” material balance alone was 1.15, on the V.C.C. for each extraction it was 1.4 and for the method utilizing the contact areas and the “no loss” material balance it was 1.08 feet. The best batch refined oil had a viscosity index of 85. The best column refined oil had a viscosity index of 73.5. In both cases these values were reached using a ratio of 5.2 parts of furfural to one part of oil by weight and subsequent increases in this ratio did not improve the properties. / Master of Science

A RMN em baixo campo (RMN-BC) é uma importante ferramenta analítica que vem sendo usada para substituir os métodos clássicos de análise. As principais características da RMN-BC sobre esses métodos são: rapidez da análise, pouca ou nenhuma preparação da amostra, análise não-invasiva e não-destrutiva e não tem descarte de produtos químicos. O presente trabalho avaliou o uso da RMN-BC com sensor (ímã e sonda) unilateral (RMNU). Neste equipamento de baixo custo, a região de análise é projetada para frente do imã, o que permite analisar amostras com grande volume, diferente dos espectrômetros convencionais onde o tamanho da amostra é limitado pelo gap ou bore do ímã. Como o sensor RMNU possui um intenso gradiente de campo magnético é possível investigar o comportamento da amostra em diferentes alturas. Essa propriedade foi explorada para medir a temperatura e a difusividade térmica de sementes de macadâmia em três profundidades. Para isso fez-se uma curva de calibração com o tempo de relaxação transversal (T2) do óleo da semente versus a temperatura. Os resultados obtidos com a RMNU foram coerentes com encontrados na literatura usando sensores invasivos como termopares. Também foram realizadas análises de viscosidade de óleos lubrificantes automotivos dentro das embalagens utilizando a sequência de CPMG. Com o método foi possível discriminar se o óleo base é mineral ou sintético. O sensor RMNU não foi sensível para identificar amostras de diesel com diferentes composição e origem. Para isso usou-se espectrômetro de RMN convencional onde analisou 118 blendas de diesel/biodiesel/óleo vegetal, em que se variou a refinaria, teor de enxofre do diesel (S500 e S10), a origem do biodiesel e do óleo. Os modelos de classificação de análise multivariada apresentaram alta capacidade de distinguir as respectivas blendas. Investigou-se também o uso do acoplamento indutivo para ampliar a região de detecção do sensor a partir da sua superfície. O acoplamento permitiu aumentar da região sensível de 2 mm para 20 mm. Esse sistema foi usado para monitorar a cura de uma amostra de gesso utilizando a sequência de CPMG. / The Low-Field NMR (LF-NMR) is an important analytical tool that has been used to replace the classical methods of analysis. The main features of LF-NMR about these methods are: speed of analysis, little or no sample preparation, non-invasive and non-destructive analysis and no disposal of chemicals. This study evaluated the use of LF-NMR with sensor (magnet and probe) unilateral (UNMR). In this low cost equipment, the region of analysis is projected forward of the magnet, which allows analyzing samples in large volumes, unlike conventional spectrometers where the sample size is limited by the gap or bore of the magnet. As UNMR sensor has an intense magnetic field gradient is possible to investigate the behavior of the sample at different heights. This property has been exploited to measure the temperature and the thermal diffusivity Macadamia seed at three depths. For this became a calibration curve with the transverse relaxation time (T2) of the seed\'s oil versus temperature. The results obtained with the UNMR were consistent with the one found in literature, using invasive sensors such as thermocouples. They were also held viscosity analysis of automotive lubricants in the packaging using the CPMG sequence. With the method it was possible to discriminate whether the base oil is mineral or synthetic. The UNMR sensor was not sensitive enough to diesel samples with different composition and origin. To it was used conventional LF-NMR spectrometer, where 118 blends diesel / biodiesel / vegetable oil, as it the refinery varied, sulfur diesel (S500 and S10), the source of biodiesel and oil were analyzed. The multivariate classification models showed high ability to distinguish their blends. It was also investigated using inductive coupling to expand the sensor detection region from its surface. Coupling allowed to increase the sensitive region of 2 mm to 20 mm. This system was used to monitor the cure of plaster sample using the CPMG sequence.

A RMN em baixo campo (RMN-BC) é uma importante ferramenta analítica que vem sendo usada para substituir os métodos clássicos de análise. As principais características da RMN-BC sobre esses métodos são: rapidez da análise, pouca ou nenhuma preparação da amostra, análise não-invasiva e não-destrutiva e não tem descarte de produtos químicos. O presente trabalho avaliou o uso da RMN-BC com sensor (ímã e sonda) unilateral (RMNU). Neste equipamento de baixo custo, a região de análise é projetada para frente do imã, o que permite analisar amostras com grande volume, diferente dos espectrômetros convencionais onde o tamanho da amostra é limitado pelo gap ou bore do ímã. Como o sensor RMNU possui um intenso gradiente de campo magnético é possível investigar o comportamento da amostra em diferentes alturas. Essa propriedade foi explorada para medir a temperatura e a difusividade térmica de sementes de macadâmia em três profundidades. Para isso fez-se uma curva de calibração com o tempo de relaxação transversal (T2) do óleo da semente versus a temperatura. Os resultados obtidos com a RMNU foram coerentes com encontrados na literatura usando sensores invasivos como termopares. Também foram realizadas análises de viscosidade de óleos lubrificantes automotivos dentro das embalagens utilizando a sequência de CPMG. Com o método foi possível discriminar se o óleo base é mineral ou sintético. O sensor RMNU não foi sensível para identificar amostras de diesel com diferentes composição e origem. Para isso usou-se espectrômetro de RMN convencional onde analisou 118 blendas de diesel/biodiesel/óleo vegetal, em que se variou a refinaria, teor de enxofre do diesel (S500 e S10), a origem do biodiesel e do óleo. Os modelos de classificação de análise multivariada apresentaram alta capacidade de distinguir as respectivas blendas. Investigou-se também o uso do acoplamento indutivo para ampliar a região de detecção do sensor a partir da sua superfície. O acoplamento permitiu aumentar da região sensível de 2 mm para 20 mm. Esse sistema foi usado para monitorar a cura de uma amostra de gesso utilizando a sequência de CPMG. / The Low-Field NMR (LF-NMR) is an important analytical tool that has been used to replace the classical methods of analysis. The main features of LF-NMR about these methods are: speed of analysis, little or no sample preparation, non-invasive and non-destructive analysis and no disposal of chemicals. This study evaluated the use of LF-NMR with sensor (magnet and probe) unilateral (UNMR). In this low cost equipment, the region of analysis is projected forward of the magnet, which allows analyzing samples in large volumes, unlike conventional spectrometers where the sample size is limited by the gap or bore of the magnet. As UNMR sensor has an intense magnetic field gradient is possible to investigate the behavior of the sample at different heights. This property has been exploited to measure the temperature and the thermal diffusivity Macadamia seed at three depths. For this became a calibration curve with the transverse relaxation time (T2) of the seed\'s oil versus temperature. The results obtained with the UNMR were consistent with the one found in literature, using invasive sensors such as thermocouples. They were also held viscosity analysis of automotive lubricants in the packaging using the CPMG sequence. With the method it was possible to discriminate whether the base oil is mineral or synthetic. The UNMR sensor was not sensitive enough to diesel samples with different composition and origin. To it was used conventional LF-NMR spectrometer, where 118 blends diesel / biodiesel / vegetable oil, as it the refinery varied, sulfur diesel (S500 and S10), the source of biodiesel and oil were analyzed. The multivariate classification models showed high ability to distinguish their blends. It was also investigated using inductive coupling to expand the sensor detection region from its surface. Coupling allowed to increase the sensitive region of 2 mm to 20 mm. This system was used to monitor the cure of plaster sample using the CPMG sequence.

Oil analysis is a broad field comprised of hundreds of individual tests that provide meaningful benefit by assessing one or more properties of lubricants or machines. Many tests are performed on new types of oil during research and development. The lubricants chemical, physical, or lubricating properties are validated for quality control purposes and product performance classification. Much of the research in this area is devoted to the online oil degradation systems which allow getting a prompt response about the condition of lubricant. This thesis investigates the concept for monitoring oil degradation with a vibrating Kelvin probe technique. The Vibrating Kelvin probe method for measuring the work function of metals has been used since 1932. Among the applications of this technique are adsorption, corrosion, friction and other studies. A novel application of this method is proposed in this thesis. The vibrating Kelvin system was created with one static surface acting as a sampling surface and the other one electrically isolated. The interaction of the oil with one of the surfaces of a capacitor results in a signal which is synchronously measured. The oil molecules adsorb on the surface of one of the plates and form a space charge layer which changes the work function of that surface. Oil prepared by intentional oxidation was used to evaluate and to monitor the ability to see changes in oil.

Zinc dialkyldithiophosphates (ZDTPs) are widely incorporated in lubricant formulations as anti-oxidant and anti-wear additives. Recent years have seen the emergence of considerable research aimed at defining the mode of action of these compounds. Despite this, the mechanistic action of ZDTPs in their capacity as both anti-wear and anti-oxidant agents remains ill defined. Previous investigations have used a wide variety of techniques, however, electrochemical methods have been poorly exploited. This thesis describes application of electrochemical techniques to the study of zinc ndibutyldithiophosphate (Buⁿ-ZDTP) in an investigation of the value of such methods as a tool for ZDTP analysis. A comprehensive study of Bun-ZDTP redox activity under standard electrochemical conditions has been implemented. Using cyclic voltammetry, Buⁿ-ZDTP has been shown to be oxidised in an irreversible 2 electron transfer process. The diffusion coefficient of this species in DMF has been calculated via rotating disc electrode (RDE) voltammetry. Buⁿ-ZDTP reduction proceeds via nucleation of zinc at the electrode surface. The limiting current of the 2 electron reduction process is lower than previously observed for Buⁿ- ZDTP oxidation. This occurs since zinc deposition is confined to growth centres which effectively limit the electroactive area of the electrode. A more thorough investigation of zinc nucleation at the electrode surface was undertaken using chronoamperometry. Transients plotted in dimensionless form were compared to theoretical models of nuclear growth. The potential of atomic force microscopy as a promising technique for the imaging of ZDTP filming action has been demonstrated. Ex-situ atomic force microscopy was conducted of electrode surfaces following reduction in Buⁿ-ZDTP solution under cyclic and RDE voltammetric conditions. Development of a variable elevated temperature apparatus for the study of Buⁿ-ZDTP under conditions more typical of an engine environment has been described. Application of the system to a wide range of electrochemical problems was demonstrated as an illustration of the advantages of this novel experimental approach. Studies of N, N, N/, N/-tetramethyl-p-phenylenediamine and tris(4-bromophenyl)amine oxidation yielded diffusion co-efficients (D) at elevated temperatures from which activation parameters for diffusion were obtained. Variation of D with temperature was compared to predicted theory according to the Stokes-Einstein and Wilke-Chang relationships. Studies of ortho-bromonitrobenzene and 9-chloroanthracene reduction demonstrated the elevated temperature apparatus to be a viable method for the interrogation of rapid kinetic processes. Both compounds are reduced according to an ECE mechanistic scheme where halide bond cleavage constitutes the chemical step. Since the use of microelectrodes permits "outrunning" of bond cleavage kinetics to give an n_eff of less than two, rate constants at varying temperatures were evaluated. Arrhenius plots were used to deduce activation parameters of halide bond cleavage in both compounds. Preliminary studies of Buⁿ-ZDTP redox activity under conditions more typical of an engine environment are discussed. Application of the novel microelectrode apparatus to an elevated temperature study of Buⁿ-ZDTP is described. Voltammetric investigations in toluene, a resistive solvent which serves as a convenient model for oil, are discussed.

Made available in DSpace on 2014-10-09T12:34:11Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:06:38Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Kilvya Braga (kilvyabraga@hotmail.com) on 2018-04-25T13:41:57Z No. of bitstreams: 1 JOSÉ JORGE DA SILVA JÚNIOR - DISSERTAÇÃO (PPGEM) 2017.pdf: 8878210 bytes, checksum: 8ad2b9618778b2c4268304060a0167f5 (MD5) / Made available in DSpace on 2018-04-25T13:41:57Z (GMT). No. of bitstreams: 1 JOSÉ JORGE DA SILVA JÚNIOR - DISSERTAÇÃO (PPGEM) 2017.pdf: 8878210 bytes, checksum: 8ad2b9618778b2c4268304060a0167f5 (MD5) Previous issue date: 2017-03-03 / Capes / O objetivo deste trabalho é analisar a capacidade da Termografia de monitorar o comportamento dos óleos lubrificantes SAE 20W50 API SJ e ISO VG 10 do ponto de vista térmico até o momento de ruptura do filme lubrificante, caracterizado pela brusca elevação no atrito, ruído, vibração e temperatura em ensaios de atrito cisalhante. A metodologia utilizada é baseada na análise de termogramas que indicam perfis de temperatura durante os ensaios de atrito e no momento de falha mecânica, comparando-se estes resultados com os obtidos por um termopar. Deste modo, é possível obter informações que podem ser usadas como referências visuais não invasivas durante uma situação de atrito. Os corpos de prova, constituídos por pinos cilíndricos de aço SAE 1045, são atritados contra um anel de desgaste que consiste em um rolamento travado por solda sob condição de regime de lubrificação limite. Testes foram realizados em condições crescentes de carga até 180 N em rotações de 10, 15 e 20 Hz (600, 900 e 1200 rpm). Os resultados mostram a capacidade qualitativa e quantitativa da Termografia na detecção de falhas de lubrificação, considerando a emissividade da película lubrificante de óleo igual a 0,82. Além disso, os picos de temperatura associados ao scuffing (desgaste severo causado pelo rompimento da película) mostrados pela Termografia são maiores que os mostrados pelo termopar, o que facilita a visualização deste fenômeno. Conclui-se que a Termografia pode ser usada para a detecção do rompimento da película lubrificante em ensaios de atrito do tipo pino sobre anel. / The aim of this work is to evaluate the Thermography ability to monitor the behavior of the lubricating oils SAE 20W50 API SJ and ISO VG 10 from the thermal point of view until the moment of the lubricating film rupture, characterized by the sudden elevation in the friction, noise, vibration and temperature in shear friction tests. The methodology used is based on the analysis of thermograms that indicate temperature profiles during the friction tests and at the moment of mechanical failure, comparing these results with those obtained by a thermocouple. Thus, it is possible to obtain information that can be used as noninvasive visual references during a friction situation. The specimens, consisting of cylindrical SAE 1045 steel pins, are rubbed against a wear ring consisting of a weld-locked bearing under the condition of a boundary lubrication regime. Tests were performed under increasing load conditions up to 180 N at 10, 15 and 20 Hz (600, 900 and 1200 rpm) rotations. The results show the qualitative and quantitative capacity of the Thermography in the detection of lubrication failures, considering the emissivity of the lubricating oil film equal to 0.82. In addition, the temperature peaks associated with scuffing shown by Thermography are larger than those shown by the thermocouple, which facilitates the visualization of this phenomenon. It will be concluded that the Thermography can be used for detecting the breakdown of the lubricant film in pin-on-ring friction tests.