Materials Design - Towards a Functionally Graded Electrical Conductor

In this study, we discuss functionally graded (FG) materials as pulsed electrical conductors. These conductors can be designed to be more efficient and longer lasting by applying numerical modeling tools. One focus is on limiting the thermal fatigue damage in conductors caused by very high temperatures that develop during pulse heating. We have quantified the effect of various grading functions on the pulsed Joule heating generated and the peak temperature experienced in the conductors of an electromagnetic launcher by using a 1D numerical code and a state of the art 3D coupled finite element code, EMAP3D. Because FG materials incorporate applications-tailored compositions, structures, and dimensions, smoothly graded properties in lateral and longitudinal cross sections are obtainable. The Solid Freeform Fabrication (SFF) processing approach allows for architectures with a series of important features. These features include the selective use of high efficiency conducting materials in the core, preconditioned conductor/structure interfaces, and built-in features for enhanced cooling where necessary.Mechanical Engineerin

A new species of Daldinia (Xylariaceae) from the Argentine subtropical montane forest

Based on a combination of morphological, molecular phylogenetic and chemotaxonomic evidence, a new species of Daldinia from Northwest of Argentina is described. Daldinia korfii is morphologically related to D. placentiformis, but differs in having brown vinaceous, KOH-extractable pigments and the tissue below the perithecial layer is composed of inconspicuous to conspicuous alternating zones in the new taxon.Fil: Sir, Esteban Benjamin. Fundación Miguel Lillo. Dirección de Botánica. Instituto de Micologia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lambert, C.. Helmholtz-Zentrum für Infektionsforschung; AlemaniaFil: Wendt, L.. Helmholtz-Zentrum für Infektionsforschung; AlemaniaFil: Hladki, Adriana Ines. Fundación Miguel Lillo. Dirección de Botánica. Instituto de Micologia; ArgentinaFil: Romero, Andrea Irene. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Micología y Botánica. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Micología y Botánica; ArgentinaFil: Stadler, M.. Helmholtz-Zentrum für Infektionsforschung; Alemani

A 10-bit SAR ADC with an Ultra-Low Power Supply

This paper presents a successive approximation analog-to-digital converter (SAR ADC) design, which operates with a 0.2 V power supply. The design utilizes a dynamic bulk biasing scheme to dynamically adjust the relative NMOS and PMOS strengths, which are very sensitive to temperature, process, and mismatch variations at low supply voltages. The design achieves a very low power consumption due to the 0.2 V supply. Several circuits in the design are optimized for full functionality at 0.2 V. Extracted simulations show a total power consumption of 9 nW with a peak SNDR of 61.3 dB and a Walden Figure of Merit of 1.91 fJ/conversion-step

Spinal column shortening versus revision detethering for recurrent adult tethered cord syndrome: a preliminary comparison of perioperative and clinical outcomes.

OBJECTIVE:Recurrent tethered cord syndrome (TCS), believed to result from tension on the distal portion of the spinal cord, causes a constellation of neurological symptoms. Detethering surgery has been the traditional treatment for TCS. However, in cases of recurrent TCS, there is a risk of new neurological deficits developing, and subsequent retethering is difficult to prevent. Spinal column shortening has been proposed as an alternative technique to reduce the tension on the spinal cord without incurring the morbidity of revision surgery on the spinal cord. The authors compared the perioperative outcomes and morbidity of patients who were treated with one or the other procedure. METHODS:The medical records of 16 adult patients with recurrent TCS who were treated between 2005 and 2018 were reviewed. Eight patients underwent spinal column shortening, and 8 patients underwent revision detethering surgery. Patient demographics, clinical outcomes, and perioperative factors were analyzed. The authors include a video to illustrate their technique of spinal column shortening. RESULTS:Within the spinal column shortening group, no patients experienced any complications, and all 8 patients either improved or stabilized with regard to lower-extremity and bowel and bladder function. Within the revision detethering group, 2 patients had worsening of lower-extremity strength, 3 patients had worsening of bowel and bladder function, and 1 patient had improvement in bladder function. Also, 3 patients had wound-related complications. The median estimated blood loss was 731 ml in the shortening group and 163 ml in the revision detethering group. The median operative time was 358 minutes in the shortening group and 226 minutes in the revision detethering group. CONCLUSIONS:Clinical outcomes were comparable between the groups, but none of the spinal column shortening patients experienced worsening, whereas 3 of the revision detethering patients did and also had wound-related complications. Although the operative times and blood loss were higher in the spinal column shortening group, this procedure may be an alternative to revision detethering in extremely scarred or complex wound revision cases

Determination of the orbital moment and crystal field splitting in LaTiO3_{3}

Utilizing a sum-rule in a spin-resolved photoelectron spectroscopic experiment with circularly polarized light, we show that the orbital moment in LaTiO$_3$ is strongly reduced both below and above the N\'{e}el temperature. Using Ti $L_{2,3}$ x-ray absorption spectroscopy as a local probe, we found that the crystal field splitting in the $t_{2g}$ subshell is about 0.12-0.30 eV. This large splitting does not facilitate the formation of an orbital liquid

Boston University Concert Choir, October 27, 1990

This is the concert program of the Boston University Concert Choir performance on Saturday, October 27, 1990 at 8:30 p.m., at Marsh Chapel, 735 Commonwealth Avenue. Works performed were Tu es Petrus by Giovanni Pierluigi da Palestrina, Sicut cervus by G. P. d. Palestrina, A un giro sol de' begl'occhi lucenti by Claudio Monteverdi, Si ch'io vorrei morire by C. Monteverdi, Waldesnacht, Op. 62 No. 3 by Johannes Brahms, Im Herbst, Op. 104 No. 5 by J, Brahms, Luci care, luci belle, K.V. 346 by Wolfgang Amadeus Mozart, Ecco quel fiero istante, K.V. 436 by W. A. Mozart, Mi lagneró tacendo, K.V. 437 by W. A. Mozart, Se lontan ben mio tu sei, K.V. 438 by W. A. Mozart, Due pupille amabile, K.V. 439 by W. A. Mozart, Piú non si trovano fra mille amante, K.V. 439 by W. A. Mozart, and Cantata BWV 106: Gottes Zeit ist die allerbeste Zeit by Johann Sebastian Bach. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund