Centreless burnishing and influence of its parameters on machining effects

The article presents the results of examining the centreless roller burnishing technology worked out by the authors. The structure and the construction details of a prototype device for the centreless burnishing of shafts were presented. The experiments were carried on using 41Cr4 steel workpieces. The effects of the workpiece hardness, the surface roughness before burnishing, the deformation multiplicity and the tool interference on the roughness and the geometric structure after burnishing were investigated. The significant influence of the above parameters was confirmed and described as a mathematical power model. It also showed a beneficial effect of centreless burnishing parameters on roughness and geometric structure of the surface.     

New derivatives of phenylamine as novel building blocks of conducting polymers

A novel phenylamine substituted derivatives possessing different photochromic groups were investigated. Using the electrochemical and spectroelectrochemical measurements the electrochemical activity of the monomers and polymers have been studied. The results indicate good film forming properties most of the monomers and stability of the forming films. The polymeric films include diphenylamine or triphenylamine unit and five member heterocycle ring moieties.     

Computer art generated by the method of secants in the complex plane

Computer graphics is used to represent the behavior of the method of secants in the complex plane. As with Newton's method, the method of secants produces fractal structures.     

Synthesis and characterization of titanium-45S5 Bioglass nanocomposites

Titanium-45S5 Bioglass nanocomposites were synthesized by the combination of mechanical alloying and powder metallurgy process. The structure, mechanical and corrosion properties of these materials were investigated. Microhardness test showed that the obtained material exhibits Vicker’s microhardness as high as 770 HV_0.2 for Ti-20 wt.% 45S5 Bioglass, which is more than three times higher than that of a conventional microcrystalline titanium (225 HV_0.2). Additionally, titanium-10 wt.% of 45S5 Bioglass nanocomposites (i_c = 1.20 × 10⁻⁷ A/cm², E_c = −0.42 V vs. SCE) were more corrosion resistant than microcrystalline titanium (i_c = 2.27 × 10⁻⁶ A/cm², E_c = −0.36 V vs. SCE). In vitro biocompatibility of these materials was evaluated and compared with a conventional microcrystalline titanium, where normal human osteoblast (NHOst) cells from Cambrex (CC-2538) were cultured on the disks of the materials and cell growth was examined. The morphology of the cell cultures obtained on Ti-10 wt.% 45S5 Bioglass nanocomposite was similar to those obtained on the microcrystalline titanium. Mechanical alloying and powder metallurgy process for the fabrication of titanium-45S5 Bioglass nanocomposites with a unique microstructure, higher hardness, lower Young’s modulus and better corrosion resistance, in comparison to microcrystalline titanium, were developed. On the other hand, Ti-10 wt.% 45S5 Bioglass composites posses higher fracture toughness compared to 45S5 Bioglass. The proper modification of chemical composition and microstructure of Ti-bioceramic nanocomposites can expand the use of titanium in the biomedical fields.     

Capturing a Qualitative Model of Network Performance and Predicting Behavior

This paper describes a method for constructingbehavior models of communication networks. The methodutilizes archived quantitative performance data createdby a network management platform to create a Quantitative/Qualitative (Q²)Dynamic System representation. The Q²representation captures the predominant qualitative(symbolic) states of the network, qualitative inputevents and transitions among the states resulting from these events. Thissymbolic model allows the network manager to understandthe current system behavior, and predict future possiblebehaviors. We evaluated the method on two sets of archive data. The method shows promise foruse in network management, including network monitoring,fault detection, prognostication andavoidance.     

Biologisches Verfahren zum unspezifischen Nachweis g?rungshemmender Substanzen in Wein

Zusammenfassung Zum Nachweis von gärungshemmenden Steffen im Wein wurde eine neue biologische Methode entwickelt, die auf dem Prinzip er Keimzahlbestimmung durch stufenweise Verdünnung beruht. Für den Test wird die zu untersuchende Probe steril in eine Reihe von Reagensgläserm gefüllt und mit dem gleichen Volumen eines Nährmediums versetzt, das außer den Nährstoffen zusätzlich Brenztraubensäure zum Binden von schwefliger Säure enthält Diesem Testgemisch wird eine sehr verdünnte Suspension einer alkoholresistenten Hefe zugesetzt. Die Verdünnung wird so gewählt, daß in der höchsten Verdünnungsstufe nur noch einzelne Zellen je Einsaatvolumen vorhanden sind. Nach der Einsaat wird das Testgemisch 4–6 Tage bei 27° C gehalten. In allen Röhrchen, denen Hefezellen zugesetzt werden, wird eine deutliche Trübung und Gasbildung sichtbar werden. Enthält die Probe jedoch Hemmstoffe, so verringert sich die Anzahl der Röhrchen, in denen e in Hefewachstum erkennbar ist. Mit dieser Keimzahlmethode werden Hemmstoffe unspezifisch nachgewiesen; für folgende Substanzen wurde die Nachweisgrenze in Wein bestimmt: Kaliumsorbat 60 mg/l, Natriumazid 1 mg/l, Natriumfluorid 10 mg/l, p-Chlorbenzoesäure 3 mg/l, Actidion < 0,05 mg/l, Monobromessigsäure 2 mg/l. Da die Methode nicht spezifisch ist, können such Fungicide nachgewiesen werden, wenn sie in ausreichender Konzentration vorliegen. — Infolge der Verdünnung wird die Keimzahlmethode durch den Alkoholgehalt des Weines niche beeinträchtigt. Bei der Untersuchung einer Reihe von Weinen wurden natürlich vorkommende Hemmstoffe nicht gefunden.

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Biological method for unspecific detection of preservatives in wine

Summary Employing the method of the determination of the most probable number of single cell organisms by step-wise serial dilution, a new method for the detection of preservatives in wine has been developed. The sample to be investigated is distributed into a series of test tubes, to which the equal volume of a nutrient solution is added. This reduces the alcohol content of the sample sufficiently. The added solution contains sugar, yeast extract and pyruvie acid, which is needed to bind free SO₂ which might be present in the wine sample. To this mixture very dilute suspensions of cells of a yeast strain resistant to alcohol are added. The dilution of this suspension is such that the highest dilution used for inoculation contains no or only a single yeast cell. The same volume of this inoculum (1 ml) is used for each test tube with the mixture of wine sample and nutrient solution. After inoculation the tubes are kept for 4–6 days at 27° C. All tubes that have received an inoculum containing at least one viable yeast cell will show growth by becoming turbid. The most probable number of cells is calculated from these results. If however, the wine sample contains preservatives, the number of tubes showing yeast growth and thus the most probable number of cells will be reduced. This reduction in the most probable number can be used for the unspecific detection of preservatives. The detection limits of the following compounds were found to be potassium sorbate 60 mg/l, sodium azide 1 mg/l, sodium fluoride. 10 mg/l, p-chlorobenzoic acid 3 mg/l, actidione < 0.05 mg/l, monobromoacetic acid 2 mg/l. The proposed method is somewhat more sensitive than the usual fermentation test. Fungicides and detergents can also be detected, when they are present in inhibiting amounts. The disadvantage of the method is the need to sterilize the sample, but this can be done by simple means. In an investigation of white and red wines no natural inhibitors were found which interfer with the method for the unspecific detection of preservatives.

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Diese Arbeit wurde durch Gewährung einer Sachbeihilfe des Forschungsringes des Deutschen Weinbaues unterstützt.     

"Clinical psychology in other lands": Correction and Thanks.

Reports two inaccuracies in the paper by Henry P. David, Clinical psychology in other lands. In D. Brower & L. E. Abt (Eds.), Progress in clinical psychology. Vol. III. New York: Grune & Stratton, 1958; (see record 1959-08255-000), which mentions the article by R. Zajonc (see record 1959-02442-001) concerning psychology in Poland. In this correction, Choynowski affirms that he is head, not of the Psychology Section of the Polish Academy of Sciences (which does not exist), but of the Psychometrical Laboratory of this academy to which belong many research institutes. Secondly, he states that the academy also does not envisage a subsection on clinical psychology. He notes that he is afraid that David got these facts from him, but then it is another example of unfortunate semantical misunderstanding in international communication. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of High-Temperature Treatment on n–p Transition in Titania

This paper reports the electrical conductivity and Seebeck coefficient (thermopower) values derived for TiO₂ (rutile) at a temperature range of 923–1353 K and p _O2 of 5 Pa–100 kPa. The effect of high-temperature treatment on the electrical properties of polycrystalline samples is discussed in terms of defect models. Samples sintered at ≥1573 K, as well as the single crystals, show n - to p -type transition, whereas samples sintered at 1473 K remain n -type throughout testing. No effect of grain size on thermopower is observed. These results are consistent with the defect disorder model assuming that titanium vacancies formed during high-temperature treatment (1473–1673 K) are frozen at the measuring temperature (923–1323 K).     

Copolymerization of alkyl acrylates with triallyl cyanurate: Kelen-Tüdös method applied for determining copolymerization reactivity ratios

The copolymerization of methyl acrylate (MA), ethyl acrylate (EA), straight-chain butyl acrylate (n-BA) and styrene (S) with triallyl cyanurate (TAC) has been studied in bulk at 343±1 K using benzoyl peroxide as initiator. The reactivity ratios of the monomers are determined by the Fineman-Ross (F-R) method and compared to those determined by the Kelen-Tüdös (K-T) method.