1970 April, Memphis State University bulletin

Vol. 58, No. 3 of the Memphis State University bulletin containing the day and evening schedule of classes for summer session 1970, 1970 April.https://digitalcommons.memphis.edu/speccoll-ua-pub-bulletins/1322/thumbnail.jp

Microstructural control and properties optimization of microalloyed pipeline steel

A series of physical simulations, with parameters resembling those of industrial rolling, were applied using a thermo-mechanical simulator on microalloyed bainitic pipeline steel to study the influence of varying the processing parameters on its microstructure evolution and mechanical properties. In this study, the austenitization temperature and roughing parameters were kept unchanged, whereas the parameters of the finishing stage were varied. The developed microstructures were studied using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is illustrated that selecting the appropriate cooling strategy (without altering the deformation schedule) can produce an optimized microstructure that breaks through the strength–ductility trade-off. Increasing the cooling rate after the finishing stage from 10 K·s−1 to 20 K·s−1 activated the microstructure refinement by effective nucleation of acicular ferrite and formation of finer and more dispersed martensite/austenite phase. This resulted in a remarkable enhancement in the ductility without compensating the strength. Furthermore, a pronounced strength increase with a slight ductility decrease was observed when selecting the appropriate coiling temperature, which is attributed to the copious precipitation associated with locating the coiling temperature near the peak temperature of precipitation. On the other hand, it was observed that the coiling temperature is the predominant parameter affecting the strain aging potential of the studied steel. Higher strain aging potentials were perceived in the samples with lower yield strength and vice versa, so that the differences in yield strength after thermo-mechanical treatments evened out after strain aging

Electrochemical storage of energy in acrylic activated carbon fibres and activated carbons made from industrial residues

In this work the application as electrochemical capacitors of novel materials, never tested before for this propose, were investigated using classic cyclic voltammetry, chrono potentiometry, chrono amperometry and electrochemical impedance spectroscopy. The tested materials were prepared in our laboratory: a) acrylic activated carbon fibres (ACF) (samples F920, F932, F993) produced from a commercial acrylic fiber by carbon dioxide activation at 900ºC according the procedure described in ref. 1; b) activated carbons (AC) produced from a coffee industry residue, the coffee endocarp, by carbon dioxide activation (samples C823, C840, C863) and KOH activation (samples AQ62, AQ605) (please see ref. 2 for experimental details). All the materials were easily produced in monolithic shape that can be considered an advantage over other materials because the electrode pos-production step and the use of binders are not needed. The carbon materials textural, structural and chemical characteristics were very different between samples with apparent BET surface area, ABET, range from 89 to 1050m2/g, micropore volume given by S method, VS, between 0.04 and 0.50cm3/g, oxygen and nitrogen content in the range 7-16 and 1-8wt%, respectively, and microcrystalline dimensions La and Lc within the limits 2-4 and 1-4nm, respectively. The higher specific capacitance was observed for samples C823, C840 and C863. The determined values were 149, 176 and 167 F/g, respectively. Apparently, ACF perform worse than AC as indicated by lower capacitance determined that reaches the maximum value of 90F/g at scan rate of 1mV/s. Nevertheless, the specific capacitance increases with ABET and VS increase, independently of the material, which could indicate that the porous properties are the determinant factor to the capacitance performance of this type of carbon materials. The heteroatoms content have peculiar influence, as for instance the specific capacitance shows an increase with oxygen content for ACF samples and an opposite trend for AC samples. Taking into account the medium microcristalite area, evaluated by LaxLc, we can observe higher values of capacitance for bigger areas. This tendency is mainly due to the incremented ability for charge accumulation in denser aromatic structures. The obtained voltammograms show a slightly distorted rectangular shape with no distinct peaks. The distortion is more visible in the redox part of the curve, which proves of the presence of pseudocapacitance phenomenon. During CESEP07 we will also show the results of electrochemical and liquid phase oxidation in the electrochemical capacitors behaviour. As main conclusion we can refer the high potential of the novel carbon materials tested that must be improved by enlarging the mean pore width in order to facilitate the electrolyte wetting and faster ionic motion within the material structure

1969 April, Memphis State University bulletin

Vol. 58, No. 3 of the Memphis State University bulletin containing the day and evening schedule of classes for summer session 1969, 1969 April.https://digitalcommons.memphis.edu/speccoll-ua-pub-bulletins/1319/thumbnail.jp

ELECTRONIC STRUCTURE OF FINITE-LENGTH CARBON NANOTUBES: CROSSOVER FROM FULLERENES TO NANOTUBES

Finite-size effects in armchair (n,n) carbon nanotubes are studied as a function of the tube length by using the generalized tight-binding calculations. End structures of the tubes considered here are caps formed from hemispherical pieces of Ih fullerenes and hydrogen-free open ends. It has been clarified that the dimensionality in electronic structures of the finite-length nanotubes only depends on an aspect ratio of the tube diameter to the length of the cylindrical region. The aspect ratio where the finite-length tubes exhibit one-dimensional properties is found to be about four. The results corroborate that the nanotubes with their length of 10–100 nm experimentally observed could be regarded as one-dimensional electron systems

Kv7 and Kv11 channels in myometrial regulation.

Ion channels play a key role in defining myometrial contractility. Modulation of ion channel populations is proposed to underpin gestational changes in uterine contractility associated with the transition from uterine quiescence to active labour. Of the myriad ion channels present in the uterus, this article will focus upon potassium channels encoded by the KCNQ genes and ether-à-go-go-related (ERG) genes. Voltage-gated potassium channels encoded by KCNQ and ERG (termed Kv7 and Kv11, respectively) are accepted as major determinants of neuronal excitability and the duration of the cardiac action potential. However, there is now growing appreciation that these ion channels have a major functional impact in vascular and non-vascular smooth muscle. Moreover, Kv7 channels may be potential therapeutic targets for the treatment of preterm labour

The bryophyte flora of nature reserves in central Chile : 1., the moss flora of Los Ruiles Nature Reserve near Talca

The moss flora of the Los Ruiles Nature Reserve, Maule region (VII), central Chile was investigated. Los Ruiles is a small forest reserve dominated by Nothofagus trees and surrounded by plantations of Pinus radiata. The moss species list contains 72 taxa, among which are 36 species newly reported for the Maule region. Several species reach their northernmost known limit in the reserve, including Achrophyllum magellanicum var. magellanicum, Ancistrodes genuflexa, Cryphaea consimilis, Dendrocryphaea lechleri, Lembophyllum orbiculatum, Leptostomum menziesii, Symblepharis krausei, and Zygodon papillatus. To ensure the survival of these rare or local bryophytes, an increase of the proportion of Nothofagus trees in the forests surrounding the reserve is desirable

InterferenceAnalyzer: Tools for the analysis and simulation of multi-locus genetic data

BACKGROUND: Good statistical models for analyzing and simulating multilocus recombination data exist but are not accessible to many biologists because their use requires reasonably sophisticated mathematical and computational implementation. While some labs have direct access to statisticians or programmers competent to carry out such analyses, many labs do not. We have created a platform independent application with an easy-to-use graphical user interface that will carry out such analyses including the simulations needed to bootstrap confidence intervals for the parameters of interest. This software should make multi-locus techniques accessible to labs that previously relied on less powerful and potentially statistically confounded single interval or double interval techniques. RESULTS: We introduce InterferenceAnalyzer, an implementation with a user-friendly graphical interface incorporating previously developed algorithms for the analysis and simulation of multilocus recombination data. We demonstrate the use and features of the program with an example of multilocus tetrad data from the mustard plant, Arabidopsis thaliana, and the yeast, Saccharomyces cerevisiae. CONCLUSION: InterferenceAnalyzer provides easy access to the powerful and appropriate statistical tools for the multi-locus analysis of genetic data

Revised phase diagram for the Pt-Ti system from 30 to 60 at.% platinum

Alloys of the Ti-Pt system between 30 and 61 at.% Pt were studied using metallography with optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), and differential thermal analysis (DTA). A phase of nominal composition Ti4Pt3, in the range 41.7-43.4 at.% Pt was found in samples containing between 30 and 47 at.% Pt, and was apparently formed by a peritectoid reaction between β-TiPt and Ti3Pt at 1205±10°C. The eutectic reaction between Ti3Pt and β-TiPt was found to be at ∼35 at.% Pt and 1424±10°C, and the Ti3Pt phase melted at circa 1500°C. The other phase boundaries agreed with the published literature, except that a slightly wider range was found at 1200°C for β-TiPt. © 2004 Elsevier B.V. All rights reserved