Classification of the seven dimensional Lie algebras with co-dimension one nilradical

In this talk we discuss the Lie algebra classification problem in general, and introduce the techniques used for the seven-dimensional Lie algebras with co-dimension one nilradical. We will share the preliminary results for when the niradical is abelian

SEISMIC ANISOTROPY AND TIME-FREQUENCY ANALYSES DURING TAUPŌ'S 2019 UNREST

The currently active Taupō volcano (with its most recent eruptive event at ∼ 1.8 ka) was responsible for Earth’s youngest supereruption at 25.5 ka. In the past 141 years, 21 unrest events have been observed in records of seismicity, crustal deformation and changes in the lake level at Taupō. The most recent unrest was during September 2018 – September 2019, and was interpreted to be caused by a magmatic intrusion rather than by hydrothermal instabilities in the volcano (Illsley-Kemp et al., 2021). Prior seismic anisotropy studies in the North Island have identified a distinct pattern of S-wave fast orientations at Taupō volcano that do not align with the maximum horizontal stress in the region. Therefore, due to the complexity of the unrest of the caldera, we combined seismic anisotropy and time-frequency analysis to complement the current understanding of volcano dynamics over the period of unrest. We used an existing 10-year earthquake catalogue determined by Illsley-Kemp et al. (2021) to study seismic anisotropy around Lake Taupō, with a focus on temporal analysis during the unrest period. Using 35,452 high quality shear-wave splitting measurements, we obtained the median fast orientation values for 23 seismic stations around Taupō. We recognised three significant anisotropy temporal changes during the unrest period, not related to variations in the travel path of the earthquakes, and interpreted these as stress-induced changes due to magmatic processes, in accordance with the findings of Illsley-Kemp et al. (2021). Temporal stress-changes identified by seismic anisotropy were compared with the results of time-frequency analysis to determine that the magmatic intrusion did not reach shallower depths. We reviewed the continuous stream of seismic data in the time-frequency domain to identify possible low frequency signals related to volcanic activity and to compare their relationship with stress changes during the unrest period. Even though we did not identify low frequency volcanic seismic signals during 2019, we propose a preliminary catalogue of typical low frequency seismic signals at Taupō, which includes the lake microseism signal. Volcanic unrest in calderas is a frequently occurring phenomenon, and does not always imply a volcanic eruption. The improvement of monitoring techniques will allow us to understand periods of unrest in calderas for volcano preparedness and risk management.</p

Killing\u27s Equations for Invariant Metrics on Lie Groups

This article is the first in a series that will investigate symmetry and curvature properties of a right-invariant metric on a Lie group. This talk will consider Lie groups in dimension two and three and will focus on the solutions of Killing\u27s equations. A striking result is that several of the three-dimensional Lie groups turn out to be spaces of constant curvature

Enhancement of Oxidative Stabilization of Viscose Rayon Fibers Impregnated with Ammonium Sulfate Prior to Carbonization and Activation Steps

The oxidative thermal stability of microcrystalline plant-based viscose rayon cellulose fiber was improved in the presence of an ammonium sulfate solution. The structural characterization of the oxidized samples was carried out using a combination of fiber thickness, linear density, burning test, X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and infrared (IR) spectroscopy measurements. Oxidized viscose rayon fibers showed physical and chemical transformations with increasing oxidation temperature and were characterized by a reduction in fiber diameter and linear density values together with color changes with increasing oxidation temperature. The results obtained from XRD analysis showed the loss of crystallinity due to the amorphization processes. XRD analysis also showed increasing conversion to a highly crosslinked and cyclized structure with progressing temperature. The DSC and TGA measurements indicated that there was an improvement in thermal stability. The results obtained from IR spectra showed the progress of dehydrogenation and dehydration reactions. IR spectra in the 2000-800 cm(-1) region showed a loss of crystalline structure confirming the results of XRD. The IR spectra of the oxidized samples also showed the conversion of primary hydroxyl (OH) groups to carbonyl (C=O) groups and the presence of C=C double bonds arising from the formation of a cyclized and crosslinked structure. (C) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 128: 1239-1249, 201