The corrosion of steel and aluminium in calcium chloride/ammonia,magnesium chloride/methylamine and magnesium chloride/methylamine/decane

The corrosion of St 37, StE 36, Al 99,5 and Al-Mg 3 in the chemical pairs of substances calcium chloride/ammonia, magnesium chloride/methylamine and magnesium chloride/methylamine/decane was investigated. The corrosion tests were performed in autoclaves at room temperature to 180 °C. The nominal duration of the experiments was 1000 hours. Rod shaped fatigue specimens with polished surfaces served as test specimens; these were fatigue tested after the corrosion treatments. All materials tested were compatible with calcium chloride/ammonia under the experimental conditions employed. Steel and aluminium showed similar behaviour against magnesium chloride/methylamine and magnesiumchloride/methylamine/decane, respectively. At room temperature and 70°C to 80°C the corrosion of steel and aluminium was low (wall losses in the order of 1 m?m/a). Corrosion increased with increasing temperature. The activation energy for the reaction, which determined the rate of weight loss in magnesium chloride/methylamine/decane, was AE_st = 0, 60 ± 0,18 eV for steel, and AE_Al = 1, 07 ± 0,07 eV for aluminium. A corrosion treatment on aluminum fatigue specimens after 1000-1500 hours at 110 °C caused a notable decrease in fatigue strength; no such behaviour was noted for steel, even when corroded at 170 °C.     

Einflüsse bei der Prüfung der Spannungsrißkorrosion

Influence factors in the testing of stress corrosion cracking The results of the tests of stress corrosion cracking of austenitic stainless steels in MgCl₂ solution are significantly dependent on the type and method of the test. The testing method used in the Research Institute of the Schoeller-Bleckmann Steelworks Ltd. is discussed, and attention is drawn to the influence of a number of test conditions such as the preparation of the MgCl₂ solution, the preheating of the test vessel with water, the surface condition of the specimen, the diameter of the specimen, the covering of its shaft, the time at which the load is applied, and the advance potential applied. The correlation of the service life with stress, concentration and temperature is used as an example in order to show that the test method is apt to affect not only we service life but also the extent and, type of these correlations. It is therefore only in conjunction with the exact test conditions that the test results can be regarded as fully significant.     

Facilitating Organizational Decentralization Through Teleconferencing

The New Rural Society (NRS) Project is determining how communications technology can be used to improve living conditions in rural areas. An important part of this research is concerned with encouraging the creation of employment in such areas. In conjunction with this objective, NRS has conducted a series of experiments leading to the development and field test of a teleconferencing system which would help facilitate the decentralization of employment by providing an electronic alternative for face-to-face meetings. This phase of the research is described.     

Biocompatible micro-sized cell culture chamber for the detection of nanoparticle-induced IL8 promoter activity on a small cell population

In most conventional in vitro toxicological assays, the response of a complete cell population is averaged, and therefore, single-cell responses are not detectable. Such averaging might result in misinterpretations when only individual cells within a population respond to a certain stimulus. Therefore, there is a need for non-invasive in vitro systems to verify the toxicity of nanoscale materials. In the present study, a micro-sized cell culture chamber with a silicon nitride membrane (0.16 mm²) was produced for cell cultivation and the detection of specific cell responses. The biocompatibility of the microcavity chip (MCC) was verified by studying adipogenic and neuronal differentiation. Thereafter, the suitability of the MCC to study the effects of nanoparticles on a small cell population was determined by using a green fluorescence protein-based reporter cell line. Interleukin-8 promoter (pIL8) induction, a marker of an inflammatory response, was used to monitor immune activation. The validation of the MCC-based method was performed using well-characterized gold and silver nanoparticles. The sensitivity of the new method was verified comparing the quantified pIL8 activation via MCC-based and standard techniques. The results proved the biocompatibility and the sensitivity of the microculture chamber, as well as a high optical quality due to the properties of Si₃N₄. The MCC-based method is suited for threshold- and time-dependent analysis of nanoparticle-induced IL8 promoter activity. This novel system can give dynamic information at the level of adherent single cells of a small cell population and presents a new non-invasive in vitro test method to assess the toxicity of nanomaterials and other compounds.PACS: 85.35.Be, 81.16.Nd, 87.18.Mp     

Imprint lithography enabling ultra-low loss coaxial interconnects

Processing techniques have been demonstrated to fabricate a novel structure with smooth transitions, metallic shielding, and encapsulated air dielectric layers using sacrificial polymers and the three-dimensional patterning capabilities of imprint lithography. This innovative structure incorporates encapsulated air dielectrics with copper shielding. A semicircular stamp was fabricated to create the circular base of the coaxial transmission line using the reflow properties of solder, and imprinting the stamp produced smooth rounded terminations. Copper shielding was electroplated and a sacrificial photosensitive polycarbonate was patterned using a unique interaction with the copper. The polycarbonate was over-coated with a epoxycyclohexyl polyhedral oligomeric silsesquioxane (POSS) layer and then thermally decomposed to form an air cavity. A center conductor was patterned using photolithography and electro-deposition. The half-coaxial line was aligned with a sample with the top portion of the copper shielding and bonded in the imprinter to complete the structure. Imprint lithography also demonstrated the capability to planarize surfaces which simplified the buildup process, and complex structures were fabricated with a comparable number of registration steps to traditional transmission lines. The mechanical integrity of the air-clad transmission lines was also evaluated using nano-indentation.     

Ein Museum für Verbrecher? Das Projekt ?Wildereiausstellung St. Pankraz“

Zusammenfassung Im Rahmen der Dezentralen Oberösterreichischen Landesausstellung 1998 wird in der Gemeinde St. Pankraz eine Ausstellung zum Thema Wilderer im Alpenraum-Rebellen der Berge zu sehen sein. Der Aufsatz beschreibt Konzept und Inhalt dieser Ausstellung. Sie versucht, die Wilderer nicht nur negativ über ihr gesetzwidriges Handeln zu definieren, sondern die Wilderei als solche in den Mittelpunkt der Betrachtung zu stellen, sie zu verstehen und zu erklären, ohne sie zu rechtfertigen.

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A museum for criminals?

Summary An exhibit on the subject of Poachers in the Alpine Regions — Rebels of the Mountains will be shown in the village of St. Pankraz as part of the decentralized Upper Austrian State Exhibition 1998. This report describes the concept behind as well as the contents of this exhibit. The attempt is made to emphasize the motives behind the transgression of poaching, to understand and explain without justifying these acts rather than to confine the poachers within their illegal behaviour.

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Un musée pour malfrats? Le projet Exposition sur le braconnage à St Pancrace

Résumé Dans le cadre de l'exposition décentralisée du Land de Haute-Autriche en 1998, on pourra visiter dans la commune de St Pancrace une exposition sur le thème Braconniers dans les Alpes — rebelles des montagnes. Le titre évoque bien le concept et le contenu de cette exposition, qui ne cherche pas seulement à définir les braconniers de façon négative par rapport au caractère illégal de leur activité mais aussi par rapport à une approche visant à comprendre et à expliquer cette activité sans la justifier pour autant.

     

Comparison of sorption domains in molecular weight fractions of a soil humic acid using solid-state 19F NMR

Humic acid was fractionated into eight different molecular size components using ultrafiltration. Solid-state CPMAS 13C NMR demonstrated that fractions larger than 100,000 Daltons were primarily aliphatic in character, while fractions smaller than 30,000 Daltons were predominantly aromatic in character. Solid-state 19F NMR examination of the sorptive uptake of hexafluorobenzene (HFB) by HA and each of the fractions gave spectroscopic evidence for the existence of at least three sorption sites in the smaller molecular size fractions, while two predominant sorption sites could be established in the larger molecular size fractions. Sorbed HFB displayed higher mobility in the smaller, more aromatic fractions while HFB in the larger, more aliphatic fractions displayed lower mobility. The relative mobilities of HFB in each sorption domain suggest that the rigid domain may be composed of aliphatic carbon rather than aromatic carbon moieties. In larger size fractions, this domain may be the result of rigid, glassy regions composed of aliphatic molecules or side chains.     

Identification of drug glucuronides in human urine by RP-HPLC after derivatization

The reactivity of nitric oxide under a given condition is a complex function of its diffusivity and the concentration of reacting partners. Quenching by NO of luminescence from Ru and Pd chelates of mesoporphyrin IX, two molecules which exhibit phosphorescence at room temperature, was utilized to evaluate the gas concentration and apparent diffusion coefficients. The properties of Ru-mesoporphyrin, a dye not previously employed as a probe for O2 or NO, were determined and the assay was verified and used to quantify NO produced by decomposition of nitrosocysteine. The pseudo-second order quenching constants were obtained from Stern-Volmer plots measured under various conditions and used to calculate diffusion coefficients for nitric oxide in solutions, proteins and membranes. The diffusion coefficients were greater at 37 than at 25 degrees C and, at a given temperature, smaller in proteins and membranes than in water. The conclusion is that NO and O2 closely resemble each other in diffusivity but that NO is slightly less lipophilic, resulting in somewhat faster apparent diffusion in protein and slower diffusivity in lipid, relative to O2. Taking a mean diffusion coefficient for NO of 10(-7) cm2s-1, then within 10 s the mean path is 10(-3) cm, or less than the diameter of a single cell. However, at low NO and O2 concentrations, the halflife of NO will be considerably longer than 10 s, and consequently the path of NO diffusion much greater.     

First-hit speed up in ray tracing surfaces of functions of two variables

Visualizing surfaces of functions of two variables by ray tracing generally follows the techniques which have been developed for ray tracing any other surfaces. But with regard to the special features of this type of surface and the fact that, in this case, the ‘scene’ to be ray-traced normally consists of only one single object, a special ray-tracing algorithm has been developed by several authors. This paper shows how to accelerate this algorithm by applying a new technique for a fast computation of the intersections of the so-called eye rays, which means rays cast from the observer's eye into the scene, and the surface. These intersections are called first hits. Pseudocode of the new algorithm is given and examples of images are presented which show speed-up factors up to 4.8.     

Calbistrins, novel antifungal agents produced by Penicillium restrictum. I. Production, taxonomy of the producing organism and biological activity

Over a 14-year period, from 1971 to 1985, there were 15 patients referred to the Princess Margaret Hospital in Toronto for postoperative radiotherapy to the cervical lymph nodes following radical neck surgery for metastatic cancer. An intensive investigation failed to yield a primary site in any patient. All of the patients had extensive neck disease with significant indications for postoperative radiotherapy (massive neck nodes, invasion of extra nodal structures or fixation to unresectable adjacent structures). Of this highly selected group of patients with advanced neck disease: 4/15 (27%) died within one year of uncontrolled local disease, a further 2/15 (13%) died within four years of metastatic/recurrent disease, 6/15 (33%) died of intercurrent disease and 3/15 (20%) were alive with at least four years follow-up. Although all patients presented with advanced disease, survival and significant palliation was possible in this select group of patients.