“Carrying the organ” – the thing on the portative, Part 1

The present article is aimed at outlining the history and form of instruments known as portatives. Its continuation will be a paper devoted to discussing technical issues connected with designing and constructing Opus 1 Portative built by the author. The portative is an instrument belonging to the family of keyboard aerophones. It is the smallest representative of the pipe organ family – both in terms of its sound range and size. As there are not many historical instruments preserved to this day, we draw information on their form and use from how they are depicted in art. It is a testament of the evolution of portatives and their popularity – from the first mentions about them from the beginning of the 12th century to the16th century when their significance lessened. This drop in popularity of these instruments was probably connected with their technical limitations noticed at that time, the fact that they were unable to meet the requirements of the evolving music and they became ousted by other portable instruments. The construction of the portative is similar to the construction of the full-size pipe organ. We can notice the occurrence of similar components, only in a simplified and smaller form. An important discrepancy is a different treatment of air system – the portative usually has only one wedge bellow operated by the player, which allows to very precisely control the air pressure, and that is connected with the dynamics and tone colour of sound produced by the pipes. This results in playing music characteristic of portatives, i.e., similar to vocal music having greater phrasing capacities as compared to playing the full-size pipe organ. Despite the decline of interest in portatives, which could be noticed in the 16th century, nowadays portatives have been regaining popularity with musicians and organ builders. They all want to build instruments with a high level of historical accuracy as well as create portatives with modern features. Examples of the first trend can be found in Marcus Stahl’s workshop, whereas the instrument built by me follows the second trend. A great model of a portative combining both ideas is one constructed by Bartosz Żłóbiński.

Ozone production chemistry in the presence of urban plumes

Ozone pollution affects human health, especially in urban areas on hot sunny days. Its basic photochemistry has been known for decades and yet it is still not possible to correctly predict the high ozone levels that are the greatest threat. The CalNex_SJV study in Bakersfield CA in May/June 2010 provided an opportunity to examine ozone photochemistry in an urban area surrounded by agriculture. The measurement suite included hydroxyl (OH), hydroperoxyl (HO2), and OH reactivity, which are compared with the output of a photochemical box model. While the agreement is generally within combined uncertainties, measured HO2 far exceeds modeled HO2 in NOx-rich plumes. OH production and loss do not balance as they should in the morning, and the ozone production calculated with measured HO2 is a decade greater than that calculated with modeled HO2 when NO levels are high. Calculated ozone production using measured HO2 is twice that using modeled HO2, but this difference in calculated ozone production has minimal impact on the assessment of NOx-sensitivity or VOC-sensitivity for midday ozone production. Evidence from this study indicates that this important discrepancy is not due to the HO2 measurement or to the sampling of transported plumes but instead to either emissions of unknown organic species that accompany the NO emissions or unknown photochemistry involving nitrogen oxides and hydrogen oxides, possibly the hypothesized reaction OH + NO + O2 → HO2 + NO2.

Elastic Recovery Measurements Performed by Atomic Force Microscopy and Standard Nanoindentation on a Co(10.1) Monocrystal

Atomic force microscopy (AFM) nanoindentation experiments were performed on a Co(10.1) monocrystal. Using AFM line scans, we deduced the elastic recovery, which is an intrinsic parameter of the studied material. The comparison of these elastic recovery values with those calculated by standard nanoindentation shows a fair agreement for forces higher than 400 μN with an important discrepancy for lower forces. This difference is attributed to tip shape effects and to the AFM cantilever elastic deformation. Furthermore, the material hardness was measured from AFM images of the imprint by considering the lateral dimension L. In this case, the obtained values are practically independent from the applied load. Moreover, a simple model based on geometrical considerations is proposed to correct hardness values calculated from the residual depth.

Continuum and emission line observations of Wolf-Rayet stars: single and “WR+abs” objects

The UV — IR properties of the continuous energy distribution of single WR stars in the Galaxy and LMC are reviewed. The observed, dereddened distributions may be approximated as a power law Fλ ∼ λ−α with a non-Rayleigh Jeans range of α directly associated with the emission of excess flux over the full wavelength range and across all spectral subtypes. The observational results are compared to published NLTE models, where we find an important discrepancy in the frequency distribution of α for Galactic WN stars. A dependency of emission line equivalent widths on the continuum flux at line center is discussed; the systematic offset of the absorption line (but otherwise presumed single) objects is examined, and the observed behavior is compared to models and explained with simple theory.

Further Analysis of Minor's Consent Bill

Two model bills for minors' consent for health services have been published in Pediatrics in 1973, one espoused by the Youth Committee of AAP, the other by the Society of Adolescent Medicine.1-2 In my endeavor to promote the concept of the bills among pediatricians, I became aware that an important discrepancy regarding birth control in the AAP bill is not clearly evident to the reader. One should be cognizant of it before initiating legislation. Although "contraceptive advice and devices" are included in the definition of "Health Services" in the AAP bill, section three dealing specifically with minors' consent limits it to "any minor who professes or is found to be pregnant."

The photolysis of ammonia

It has been shown in the preceding paper that the hypothesis that hydrazine is responsible for the anomalously low hydrogen atom concentration in the decomposition of ammonia must be abandoned. In order to explain this important discrepancy some new experimental techniques require to be developed which will settle the matter without appeal to further hypotheses. There are two general explanations of the discrepancy: (1) the hydrogen atoms are not produced as fast as that calculated on the assumption that every ammonia molecule absorbing a quantum necessarily decomposes, (2) that some entity not yet recognized removes hydrogen atoms at a rate faster than that at which they normally recombine. In this paper methods will be described in which these two problems are solved, and finally there is a discussion of the photochemistry of ammonia in the light of the new results obtained during these experiments.