Undergraduate Research

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A computer-controlled digital pulse programmer for pulse NMR
(University of New Brunswick, 1979) Hale, Michael Edward
A versatile and flexible digital pulse programmer for pulse NMR experiments is described. Independently variable controls for pulse widths (0.1 μsec to 999.9 sec), delay between pulses (0.1μ sec to 999. 9 sec), sequence period (0.1μ sec to 9999.9 sec) and trigger delay (0.1 μsec to 9999.9 sec) are brought to the front panel. The programmer can be used under computer as well as manual control. The programmer is designed to be used with a DEC LSI-11 microcomputer having a Heathkit H11-2 parallel interface.
A neutron technique for detection of explosive-like materials
(University of New Brunswick, 1989) Lord, Paul Michel; Hussein, Esam
A method for detecting explosives in luggage using a combination of neutron scattering and transmission measurements was investigated. Ammonium nitrate (commercial fertilizer) was used in the laboratory as an explosive- like material. By empirical mapping of the measurements, the method was shown to be able to detect the presence of fertilizer, even when surrounded by other materials. A series of simulations was carried out using the COMMM (Center-Of-Mass Multi-Media) Monte Carlo Neutron Transport Code. The results of these simulations further confirmed the feasibility of the technique.
A numerical analysis of a dynamic model pertaining to ionospheric research
(University of New Brunswick, 1996) Smith, Andrew M.
A numerical analysis of NMR spin echo attenuation due to variations in magnetic susceptibility
(University of New Brunswick, 1995) Beyea, Steven D.; Balcom, Bruce
Variations in the susceptibility of a heterogeneous sample will produce background microscopic field gradients when the sample is inserted into a magnetic field. These field gradients frequently alter the signal intensity observed in a nuclear magnetic resonance (NMR) image. A random walk simulation of the NMR spin echo experiment, with several model geometries, has been performed using Mathematica. Using this procedure a qualitative/ quantitative study has been done in an attempt to examine the role of diffusion in diminishing the observed signal intensity. The simulations will be compared to several MRI images of materials containing varying magnetic susceptibility, and various applications of this technique will be discussed.
A patch clamp system for cell-attached recordings from crayfish giant axons
(University of New Brunswick, 1991) Bakota, Martin; Sastry, K.V.L.N.
A patch-clamping system consisting of a computer controlled pA amplifier and signal averager was designed to measure currents through single ionic channels. Techniques were established for reliable micropipette (tip 0.0. <2μ) manufacture and tungsten microelectrode use in patch-clamping. Attempts were made to measure single channel currents in giant axons of crayfish (Orconectes). These were unsuccessful due to a failure to establish GΩ seals between the pipette and the plasma membrane. The failure is attributed to unclean plasma membrane surface (it was not digested with proteolytic enzymes).
A study of the infrared absorption spectra of nitric acid vapour
(University of New Brunswick, 1983) Smith, Charles Paul W.; Young, Charles
Nitric Acid is an important molecule in the stratosphere and is involved in photochemical reactions with ozone and the freons. Measurements of nitric acid have been made using balloon borne infrared spectrometers. Laboratory measurements at room and stratospheric temperatures are required to obtain the molecular parameters needed to reduce the balloon measurements and obtain absolute nitric acid amounts. This project proceeds to carry out the necessary measurements in an attempt to arrive at the integrated band intensity for nitric acid.
A study of the radiation induced attenuation in optical fibres
(University of New Brunswick, 1997) Teakles, Tony D.
Several papers on the radiation induced effects on optical fibres were s tudied and a series of properties were observed. The formation, annealing and properties of colour centres were studied. The published results on radiation induced attenuation have been examined in relation to the colour centres causing it. The potential uses, advantages and disadvantages for radiation environment fibre sensors have been studied. The use of a fibre sensor system as a personal radiation detector has been suggested.
An analysis of the ß-delayed a spectrum of 16N and the 12C (a,y) 16O cross section at stellar helium burning energies
(University of New Brunswick, 1994) Hunter, D. Gregory; DeMille, G.R.
The rate of 12C(a,y)16O reaction that occurs in helium burning stars is critical to the evolution of stars over twenty-five solar masses. By K-matrix analysis of the ß -delayed spectrum of 16N it is possible to precisely measure the astrophysical S-factor at centre-of-mass energies around 300 keV, corresponding to a temperature of 1 billion Kelvins. An updated analysis of the data from the TISOL isotope separator is presented here. Using the TISOL data and the previous y-ray data, the K-matrix parameters have been simultaneously fitted, giving a value of S(E = 300 keV) = 83 ± 16 keV b for the El part of the 12C(a,y)16.
An electron microscopic study of the effects of alcohols on rat heart mitochondria
(University of New Brunswick, 1983) Young, Katherine D.
An experimental search for optical bistability
(University of New Brunswick, 1992) Bradley, Michael Patrick
An unsuccessful attempt was made to experimentally observe dispersive optical bistability. Following this attempt, nonlinear absorption was sought. A dye solution was found which exhibited an absorption which increased with increasing input power. Transient and steady-state effects were examined experimentally and are discussed qualitatively. Unfortunately, no bistability was observed, though this can be explained. Finally, control of one laser beam by another via the nonlinear absorber was demonstrated.
An investigation of the properties of the GaAs diode laser
(University of New Brunswick, 1981) McInnis, Rodney Mark; C. Linton
The purpose of this project is to operate a commercial diode laser within its specifications and study a few properties within the framework of elementary physics calculations. The laser diodes used have some restrictive power supply parameters and exceeding them can easily destroy a laser. Experimental objectives could only be achieved after several pieces of electronic equipment were designed and built, such as the temperature regulator, Hex. display, avalanche photodiode detector and power supply, and laser power supply. Upon completion of the hardware, the diode laser was examined under the following experiments: -spectral distribution above and below threshold current -mode structure - peak wavelength as a function of temperature - spectral distribution at different peak currents -beam divergence -threshold current as a function of temperature
Atmospheric parameters derived using an elastic backscatter L.I.D.A.R. system
(University of New Brunswick, 1990) Donovan, David; Young, Charles
L.I.D.A.R is an acronym for light detection and ranging, and is a powerful active technique for remote sensing the atmosphere. Lidar may be said to be the optical equivalent of radar, it is in fact often referred to as "laser radar". In this paper remote sensing of the atmosphere via elastic backscatter LIDAR is discussed and elastic backscatter LIDAR data obtained using a powerful ND-YAG LIDAR at York University in Toronto Ontario is evaluated and discussed
Calcium uptake in vitro by beef heart mitochondria under the influence of Adriamycin
(University of New Brunswick, 1977) Reid, Janet L.
Adriamycin, an antibiotic which has proven to be a clinically useful chemotherapeutic agent against cancer, is found to produce fatal, dos~-related cardiac toxicity in man. Although the mechanism of this adriamycin-induced cardiomyopathy remains elusive, structural studies of affected patients and laboratory animals indicate that Adriamycin causes delayed structural alterations in the form of myocardial lesions. Recent studies have demonstrated elevated levels of calcium in tissue affected by Adriamycin, and microscopic examination of the degenerating heart tissue reveals mitochondrial degeneration and dense body formation within mitochondria in the form of calcium phosphate deposits. Therefore, it was decided to investigate the effect of Adriamycin upon calcium uptake in vitro by beef heart mitochondria, and to see how the combination of Adriamycin and A-23187 (which has a known effect upon calcium flux) affect mitochondrial calcium movement. Results obtained in this paper indicate that Adriamycin induces accumulation of calcium by heart mitochondria. Crucial to this study was the technique of atomic absorption spectroscopy used to determine calcium concentration which is based upon the absorption of energy by valence electrons of ground state calcium atoms. Use of a nitrous oxide-acetylene flame (hot) as opposed to an air-acetylene flame (cooler), based on the interference relevant in each case) is briefly discussed.
Calculation of the phase-transition point in an optical parametric amplifier
(University of New Brunswick, 1992) Banford, by Jeffery S; Professor H. Zaidi
The phase transition point for sub-harmonic generation of an optical parametric amplifier was calculated; this is the point at which squeezing of the sub-harmonics is maximum. This was done by numerically solving a system of coupled integral equations.
Cavity ringdown laser absorption spectroscopy of a radio frequency discharge
(University of New Brunswick, 2002) Richards, Clark; Adam, Allan
Cavity ringdown spectroscopy is a direct absorption technique performed with laser sources that has higher sensitivity than many other absorption techniques. It measures the rate rather than the magnitude of absorption of a molecule in a high reflectance cavity. By scanning the laser over a range of frequencies, the absorption spectrum for the molecule can be determined. The goal of this thesis is to combine the cavity ringdown technique with an rf discharge, so as to study molecules such as free radicals, without the difficulties and uncertainties associated with the previously used laser optogalvanic technique. The sensitivity and applicability of the technique have been demonstrated by measuring a molecular band of the formyl radical (HCO) with an absorption sensitivity greater than 1 part in 10(6), and comparing it to that taken with laser optogalvanic spectroscopy.
Computer simulation of a phase locked laser diode array
(University of New Brunswick, 1993) Boertjes, D. W.; Paton, B.
Conical SPRITE: A rapid, 3D MRI method for imaging solid-like materials
(University of New Brunswick, 2002) Halse, Meghan
Conical SPRITE is introduced as a rapid, 3D, proton-density weighted single point imaging technique for the study of solid-like materials with short relaxation times. The development and implementation of this technique is discussed along with a point spread function analysis of the convolution blurring effect of the combined effects of the sampling method and magnetization relaxation. Experimental results are presented that demonstrate the speed of acquisition, the dependence of signal to noise and resolution on flip angle, and the potential for manipulation of contrast through the use of magnetization preparation.
Contrast in Magnetic Resonance Images of chemical waves associated with the Belousov-Zhabotinsky reaction
(University of New Brunswick, 1994) Reid, Andrea S.; Armstrong, Robin
The determinants of contrast in magnetic resonance images of chemical waves, associated with the manganese-catalyzed BZ reaction, were investigated by studying the role of ortho-, pyro-, and meta-phosphates in the stabilization the Mn3+ ion. Relaxation times, T1 and T2, were measured for BZ reaction mixtures containing each of the phosphates (H3P04 , Na3P04 , Na4P20 7 , Na5P30 10 ) at several concentrations and over a range of time. These parameters were measured for both the "reduced" and "oxidized" states of manganese in the reaction. It is concluded that the pyro-phosphate, Na4P20 7, is the most suitable compound for MRI studies of chemical waves, particularly for studies of 3-D structures, in this system.
Correlation of underwater ambient noise
(University of New Brunswick, 2000) Rosenfeld, Andrew
The study of ambient n01se m the ocean has long been of interest to those involved in oceanography and naval research, as it relates to both underwater environmental processes and the performance of sonar systems. One of the more important aspects is the study of noise correlation between sensors, which is of particular interest because it can impart a directionality to the overall ambient noise field. Advanced sonar systems can be developed to take advantage of this directionality, filtering out waves exterior to the region of interest. This report summarizes the basic theory behind ambient noise correlation, and then develops from these basics various Monte Carlo simulation approaches of practical value. The final section discusses superdirective array processing, an advanced application of the preceding theory and simulations.
Deuterium NMR spectroscopy of CD30D adsorbed on deuterated cellulose
(University of New Brunswick, 1993) MacKenzie, Marc A.
The technique of pulse Nuclear Magnetic Resonance (NMR) was used to determine the T1, T1P, T2FID and T2CP deuteron relaxation times for deuterated methanol on deuterated cellulose ( with ad -methanol content of 0.198 grams of d - methanol per gram of cellulose ) . The temperature range studied was 133 K to 291 K using a resonant frequency of 30. 513 Mhz and a B1 locking field of 10G for the T1P measurements. The T1, T1P and T2CP relaxation times each had two components, and the T2FID relaxation time displayed a single component. The ratio of the fractions of the spins relaxing with the three long components to the fractions for the corresponding short components was seen to be approximately three to one; this is seen to relate the CD3 group to the long component, and the short component to the OD part of the methanol. The model used to describe the molecular motion was a bimodal distribution of correlation times, with the two modes corresponding to two distinct binding sites on the cellulose molecule. For room temperature , the correlation times ( Tc and activation energies calculated from this model are 6 . 8 x 10-10 s-1 , 2.000 kcals/mol ( tf, fast mode ) and 6.9 x 10-8 s-1 , 3.000 kcals/mol ( t5 , slow mode ) for the long component; for the short component, the calculated values are 3 .5 x 10-10 s-1 , 2.2 kcals/mol ( fast mode ) and 3.3 x 10-8 s-1, 1.000 kcals/mol ( slow mode ).

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