Effects of Admixes on the Compressive Strength of Permeable Concrete

Compression tests were performed on three samples of permeable concrete to evaluate the effects of admixes on a conventional permeable concrete. The first mix served as the control, representing a standard permeable concrete sample. The second mix replicated the control but added a small amount of fiberglass, accounting for 0.5% of the cement\u27s weight. The third mix again mirrored the control and incorporated the manufacturer\u27s recommended amount of a water reducing admix known as Reducer 555 . The objective of testing the two new mixes against the control mix was to evaluate the potential increase in ultimate compressive strength. Four 6” x 12” test cylinders were produced for each of the three mixes to allow destructive compression strength testing at 7, 14, 21, and 28 days from the date of initial pouring. The results of the tests revealed that there was a 168.1 psi increase in the ultimate compressive strength over the control mix with the addition of fiberglass, and that the addition of fiberglass did not greatly affect the permeability of the concrete. It also revealed that further testing would be necessary to accurately evaluate the effects of the water reducing agent, due to excess slump and the mix stratifying

Poetry and the Extremities of Language: From Concretism to Paul Celan

Despite his disdain for most contemporary German language poets, Paul Celan in his own verse shares and reflects in several ways the attitudes toward language and the possibilities of poetic speech found in the practitioners of so-called concrete poetry. Skeptical of language that had fallen victim to the verbicide of modern usage, each set out to re-create or revitalize language by using it in an anti-metaphorical sense where words, rather than functioning as bearers of meaning, are often employed as unconventional, in some cases anti-referential sign systems that have meaning only in relationship to themselves, but which simultaneously attempt to create (or discover) a pristine language. Beyond the affinity of theoretical statements made by Celan and the concrete poets, their practices of punning, word play, word deformation, reduction of words to component letters and sounds, the emphasis on the optical appearance of words and poems, and attempts to probe the essence of words by devices such as punctuation, citation, and negation all suggest that, differences notwithstanding, they shared and sought to overcome a commonly-perceived crisis of the possibilities of poetic language by a number of common means

Introduction

Introduction to the special issue on Paul Cela

Chemical Studies on Oxomolybdenum(VI,IV) Complexes as Bioinorganic Models for the Molybdenum Oxidases

The synthesis, characterization, and chemical properties of Mo(VI)o2(5-X-SSP) and Mo(VI)o2(5-X-SSE), (5-X- SSP2- = 2-((5-X-salicylidene)amino)benzenethiolate; 5-X- SSE2- = 2-((5-X-salicylidene)amino)ethanethiolate; X = Br, Cl, H, CH3O), which contain tridentate (ONS) Schiff base ligands is described. The chemical properties of these molybdenum complexes are compared with those which possess tridentate (ONO) Schiff base ligands. Cyclic voltammetry was used to obtain cathodic reduction potentials (EPC) for the quasi-reversible reduction of the cis-dioxomolybdenum (VI) complexes. Although the reductions are quasi-reversible, trends are observed in EPC both within series and when different series are compared. Cathodic reduction potentials for the four series of complexes examined span the range -l.53 to -l.05 V versus NHE. The oxygen atom transfer reactions for Mo(VI)o2(5-X-SSP) and Mo(VI)o2(5-X-SSE) with PEtPh2 were studied in detail between 30 and 60°C. The applicable rate law is +d[Mo(IV)OL]/dt = k1[Mo- (VI)o2L][PEtPh2]. The specific rate constants span the range from 8.4 x 10 (X = CH3O) to 19.6 x 10-4 M-1S-1 (x = Br) for Mo(VI)o2(5-X-SSP) at 30°C and from 21.4 x 10-4 M-1S-1 (x = CH3O) to 34.8 x 10-4 M-1S-1 (X = Br) for Mo(VI)o2(5-X-SSE) at 60°C. Only oxomolybdenum (IV) complexes are observed as products of these reactions. This is a significant result. A linear dependence is observed between log(k1X/k1H) and the Hammett oP parameter for the ligand x substituents for the two series Mo(VI)o2(5-X-SSP) (p = +0.75) and Mo(VI)o2(5-X-SSE) (p = +0.42). Activation parameter data were obtained for Mo(VI)02(5-H-SSP) (Ea = 67.9 kJ/mol, ΔH+ = 65.2 kJ/mol, ΔS+ = -86.5 J/(mol-K)) and 70.3 kJ/mol, ΔS+ Mo(VI)o2(5-H-SSE) (Ea 72.0 kJ/mol, ΔH+ = -82.6 J/(mol-K)). There are three ligand features whose effect systematically alters both the cis-dioxomolybdenum- (VI) cathodic reduction potentials and specific rate constants. These include (1) the X-substituent on the salicylaldehyde portion of each ligand; (2) the degree of ligand delocalization; and (3) the substitution of a sulfur donor atom for an oxygen donor atom. Each of these effects is considered separately with regard to both the cis-dioxo- molybdenum(VI) cathodic reduction potentials and specific rate constants, then their cumulative effect is discussed. There exists a correlation between the specific rate constants and Epc for Mo(VI)02(5-X-SSP) and Mo(VI)02(5-X- SSE). Initial results are included on the reaction of Mo(IV)02(5-H-SSP) with NO3-. Spectral results suggest conversion of Mo(IV)02(5-H-SSP) to Mo(VI)02(5-H-SSP) by way of an oxygen atom transfer reaction

Joseph Joachim Raff: A Biographical Sketch and a Conductor\u27s Analysis of his Sinfonietta, Op. 188

Despite its obscurity, Sinfonietta, Op. 188 by Joachim Raff (1822-1882) is an important chamber work for winds and should find its place more frequently on the concert programs of university wind ensembles. In order to test this hypothesis, I investigate Raff’s biography for evidence that might explain its obscurity while leaving the door open to question that status. Furthermore, I investigate the Sinfonietta from a conductor’s perspective and apply a critique of its artistic merit. Several factors explain Raff’s fall from acclaim; none of them relegate his music to permanent obscurity. Based on the composer’s historical significance, analytical results, and the work’s artistic merit, the Sinfonietta should occupy a more prominent place in the wind ensemble canon