Toward Measuring a Charge-Parity Violating Electric Dipole Moment of the Electron: Production and Pseudo-Continuous Resonance Enhanced Multiphoton Ionization of

Over one half century has passed since the possible violation of time reversal symmetry was proposed by Purcell and Ramsey. The Standard Model predicts that a value of the e-EDM |de,SM|<10-38e &middot cm that is beyond the reach of current experiment. At the same time, theories beyond the Standard Model predict an e-EDM at or near the current experimental level of |de,exp|< 1.3 × 10-27e · cm. Thus an e-EDM is a great place look for physics beyond the Standard Model.The existence of a permanent electric dipole moment would break the usual degeneracy between states of a molecule that only differ by the sign of the projection of their total angular momentum onto the axis of an external electric field. Heavy polar diatomic molecules are expected to be particularly sensitive to an e-EDM. Among the many proposed e-EDM molecules, the PbF molecule may be uniquely sensitive to an e-EDM because the magnetic moment of its ground state vanishes at a magic value of external electric field (67 kV/cm).This thesis reports on the creation of a stable molecular beam source of PbF based on the serendipitous discovery of the reaction of lead vapor and MgF2 . This thesis also gives the result of the following achievements enabled by this source: (1) The first demonstration of resonant enhanced multiphoton ionization(REMPI) detection of the molecule. (2) Experimental measurement and analysis of the rotational spectra of the 0-0 band of the B &larr X1 transition of PbF. This measurement determines the rotational temperature of our source. (3) Measurement of appearance ionization from the B and D states of the PbF molecule. This measurement improves the known ionization potential of PbF from 7.5&plusmn0.3 eV to 7.54&plusmn0.01 eV, (4) Achievement of a multiphoton ionization probe of PbF that is doubly resonant with the A &larr X1 and D &larr A transitions. This scheme allows for fully state resolved spectra of the molecule. (5) Direct measurement of the lifetime of the PbF molecule. (6) Measurement of hyperfine constants that model the interaction of the unpaired electron in 208Pb19F with the 19F nucleus.In addition to these achievements, a new type of ultra-sensitive REMPI is reported. Whereas conventional REMPI is typically carried out with pulsed laser systems, this new technique, dubbed pc-REMPI, occurs with a combination of continuous and pseudo-continuous lasers. This technique improves the detection sensitivity of the original PbF REMPI probe by a factor of 100. At the same time, the technique improves the spectra linewidth from 2 GHz to 90 MHz, allowing for full resolution of the hyperfine structure of the molecule

Absorption Wavebands for Discriminating Oxidation Time of Engine Oil as Detected by FT-IR Spectroscopy

Fourier Transform-Infrared (FT-IR) spectroscopy was used to analyze gasoline engine oil (SAE 5W20) samples that were exposed to seven different oxidation times (0 h, 24 h, 48 h, 72 h, 96 h, 120 h, and 144 h) to determine the best wavenumbers and wavenumber ranges for the discrimination of the oxidation times. The thermal oxidation process generated oil samples with varying total base number (TBN) levels. Each wavenumber (400–3900 cm1) and wavenumber ranges identified from the literature and this study were statistically analyzed to determine which wavenumbers and wavenumber ranges could discriminate among all oxidation times. Linear regression was used with the best wavenumbers and wavenumber ranges to predict oxidation time

Modeling of laser-induced breakdown spectroscopic data analysis by an automatic classifier

Laser-induced breakdown spectroscopy (LIBS) is a multi-elemental and real-time analytical technique with simultaneous detection of all the elements in any type of sample matrix including solid, liquid, gas, and aerosol. LIBS produces vast amount of data which contains information on elemental composition of the material among others. Classification and discrimination of spectra produced during the LIBS process are crucial to analyze the elements for both qualitative and quantitative analysis. This work reports the design and modeling of optimal classifier for LIBS data classification and discrimination using the apparatus of statistical theory of detection. We analyzed the noise sources associated during the LIBS process and created a linear model of an echelle spectrograph system. We validated our model based on assumptions through statistical analysis of “dark signal” and laser-induced breakdown spectra from the database of National Institute of Science and Technology. The results obtained from our model suggested that the quadratic classifier provides optimal performance if the spectroscopy signal and noise can be considered Gaussian

Erratum: Importance of Emulsification in Calibrating Infrared Spectroscopes for Analyzing Water Contamination in Used or In-Service Engine Oil. Lubricants 2018, 6, 35

The authors wish to correct the affiliation of co-author Ali Mazin Abdul-Munaim in their previous paper [...

Importance of Emulsification in Calibrating Infrared Spectroscopes for Analyzing Water Contamination in Used or In-Service Engine Oil

Using Fourier transform infrared (FT-IR) spectroscopy we investigated the water content of SAE 15W–40 diesel engine lubricating oil at various levels of contamination to establish instrument calibration standards for measuring water contamination in used or in-service engine oil by the standards of ASTM International. Since some known additives in consumer grade engine oil possess slightly hydrophilic properties, this experiment avoided changing the sample matrix with supplemental additives, such as adding surfactants, to achieve homogeneity of the original sample. The impact of sampling time after contamination on the spectral absorption signature was examined in an attempt to improve the accuracy of water contamination quantification and determine if water-soluble potassium bromide (KBr) windows were suitable for analyzing water in oil emulsions. Analysis of variance (ANOVA) modeling and limit of detection calculations were used to predict the ability to discriminate contamination levels over time. Our results revealed that the amount of water concentration in engine oil could be misinterpreted depending on the timing of the FT-IR measurement of the calibration standard after initial water contamination. Also, KBr windows are not sufficiently etched due to the limited window interaction with water molecules within micelles of emulsions to alter FT-IR spectral signatures

Investigating manifold neighborhood size for nonlinear analysis of LIBS amino acid spectra

Classification and identification of amino acids in aqueous solutions is important in the study of biomacromolecules. Laser Induced Breakdown Spectroscopy (LIBS) uses high energy laser-pulses for ablation of chemical compounds whose radiated spectra are captured and recorded to reveal molecular structure. Spectral peaks and noise from LIBS are impacted by experimental protocols. Current methods for LIBS spectral analysis achieves promising results using PCA, a linear method. It is well-known that the underlying physical processes behind LIBS are highly nonlinear. Our work set out to understand the impact of LIBS spectra on suitable neighborhood size over which to consider pattern phenomena, if nonlinear methods capture pattern phenomena with increased efficacy, and how they improve classification and identification of compounds. We analyzed four amino acids, polysaccharide, and a control group, water. We developed an information theoretic method for measurement of LIBS energy spectra, implemented manifold methods for nonlinear dimensionality reduction, and found while clustering results were not statistically significantly different, nonlinear methods lead to increased classification accuracy. Moreover, our approach uncovered the contribution of micro-wells (experimental protocol) in LIBS spectra. To the best of our knowledge, ours is the first application of Manifold methods to LIBS amino-acid analysis in the research literature

Effect of Nanocarbon on the Structural and Mechanical Properties of 6061 Aluminum Composites by Powder Metallurgy

6061 aluminum composites with 0.5 and 1 vol. % graphene nanoplatelets as well as 1 and 2 vol. % activated nanocarbon were manufactured by a powder metallurgy method. Scanning electron microscopy and Raman spectroscopy were used to study the morphology, structure, and distribution of nanocarbon reinforcements in the composite samples. Density Functional Theory (DFT) calculations were performed to understand the aluminum-carbon bonding and the effects of hybridized networks of carbon atoms on nanocarbon aluminum matrix composites. Scanning electron microscopy showed the good distribution and low agglomeration tendencies of nanoparticles in the composites. The formation of secondary phases at the materials interface was not detected in the hot-pressed composites. Raman spectroscopy showed structural changes in the reinforced composites after the manufacturing process. The results from Density Functional Theory calculations suggest that it is thermodynamically possible to form carbon rings in the aluminum matrix, which may be responsible for the improved mechanical strength. Our results also suggest that these carbon networks are graphene-like, which also agrees with the Raman spectroscopy data. Micro-Vickers hardness and compressive tests were used to determine the mechanical properties of the samples. Composites presented enhanced hardness, yield and ultimate strength compared to the 6061 aluminum alloy with no nanocarbon reinforcement. Ductility was also affected, as shown by the reduction in elongation and by the number of dimples in the fractured surfaces of the materials

Observation of a Signal Suppressing Effect in a Binary Mixture of Glycol-Water Contamination in Engine Oil with Fourier-Transform Infrared Spectroscopy

An in-depth experimental study of the matrix effect of antifreeze (ethylene glycol) and water contamination of engine oil through FT-IR spectroscopy. With a comparison of the percent by volume concentration of contaminated fresh 15W-40 engine oil, there appeared to be a noticeable reduction in the O–H stretching signal in the infrared spectrum when ethylene glycol based antifreeze was included as a contaminant. The contaminants of distilled water, a 50/50 mixture of water and commercial ethylene glycol antifreeze, and straight ethylene glycol antifreeze were compared and a signal reduction in the O–H stretch was clearly evident when glycol was present. Doubling the volume of the 50/50 mixture as compared to water alone still resulted in a weaker O–H stretching signal. The possibility that this signal reduction was due to the larger ethylene glycol molecule having fewer O–H bonds in a given sample size was eliminated by comparing samples with the same number of O–H bonds per unit volume. The strong hydrogen bonding between that of water and glycol appeared to reduce the O–H stretching signal, even after comparing the different sample types at concentrations with the same number of O–H bonds per unit volume. Tukey’s highly significant difference was used to show that samples of the 50/50 mixture and straight glycol were not reliably distinguishable from one another when comparing the same number of O–H bonds per unit volume but readily distinguishable from that of water as the lone contaminant

Observation of a Signal Suppressing Effect in a Binary Mixture of Glycol-Water Contamination in Engine Oil with Fourier-Transform Infrared Spectroscopy

An in-depth experimental study of the matrix effect of antifreeze (ethylene glycol) and water contamination of engine oil through FT-IR spectroscopy. With a comparison of the percent by volume concentration of contaminated fresh 15W-40 engine oil, there appeared to be a noticeable reduction in the O&ndash;H stretching signal in the infrared spectrum when ethylene glycol based antifreeze was included as a contaminant. The contaminants of distilled water, a 50/50 mixture of water and commercial ethylene glycol antifreeze, and straight ethylene glycol antifreeze were compared and a signal reduction in the O&ndash;H stretch was clearly evident when glycol was present. Doubling the volume of the 50/50 mixture as compared to water alone still resulted in a weaker O&ndash;H stretching signal. The possibility that this signal reduction was due to the larger ethylene glycol molecule having fewer O&ndash;H bonds in a given sample size was eliminated by comparing samples with the same number of O&ndash;H bonds per unit volume. The strong hydrogen bonding between that of water and glycol appeared to reduce the O&ndash;H stretching signal, even after comparing the different sample types at concentrations with the same number of O&ndash;H bonds per unit volume. Tukey&rsquo;s highly significant difference was used to show that samples of the 50/50 mixture and straight glycol were not reliably distinguishable from one another when comparing the same number of O&ndash;H bonds per unit volume but readily distinguishable from that of water as the lone contaminant