Titanium-containing compounds as efficient triboadditives to oils

Titanium-containing compounds soluble in mineral oils, such as titanium oleate and titanium 2-ethylhexanoate, as well as titanium dioxide nanoparticles modified by tetra(2-ethylhexyl)-thiuramdisulfide (TDS) and di(2-ethylhexyl)thiophonedisulfide (TFDS), were synthesized. Small-angle X-ray scattering was used to identify the structure of titanium carboxylates and determine the size of TiO₂ nanoparticles. The antifriction and antiwear characteristics of these compounds were studied in various-type tribometers equipped with a four-ball friction unit. A comparative study of titanium-containing compounds with the highest tribological characteristics that contained nanoparticles modified by TDS and 2-ethylhexane acid at increasing velocity of sliding was carried out. The effect of titanium-containing compounds on the relief of worn surfaces was investigated.     

Entwicklung von Planungs‐ und Sanierungskonzepten für den russischen Wohnungsbau

Für russische Wohnhäuser der ersten Periode des industriellen Bauens, so genannte “Chruschtschowki”, besteht ein hoher Sanierungsbedarf. Im Rahmen der nachfolgenden Betrachtungen werden mögliche energetische Sanierungsmaßnahmen für diese typischen russischen Wohngebäude vorgestellt. Das Ziel ist eine Angleichung an das europäische Wärmeschutzniveau und die Erstellung eines einheitlichen Berechnungsansatzes. Als Grundlage für die durchgeführten Berechnungen dienten die deutschen Vorschriften der aktuellen Energieeinsparverordnung in Kombination mit der Berechnungsnorm DIN 4108‐6 sowie DIN 4701‐10. Hierzu wurden die klimatischen Bedingungen Russlands am Beispiel der russischen Metropole Sankt Petersburg in die Berechnungen integriert. Die Datenanalyse des Bestandsgebäudes eröffnet eine große Bandbreite an Möglichkeiten zur Erhöhung der Energieeffizienz. So wird unter anderem im Zuge der Berechnungen festgestellt, dass durch relativ kostengünstige Maßnahmen zur Verbesserung des Wärmeschutzes eine bedeutende Verringerung des Endenergiebedarfs erreicht werden kann. Es werden weiterhin mögliche Sanierungsvarianten unter Einbeziehung verschiedener Materialien und Heizungsanlagen vorgestellt. Die Ergebnisse machen deutlich, dass die Zukunft russischer Wohnhäuser wie der hier dargestellten Typenserie 1‐507 alles andere als aussichtslos ist, wie oft vermutet wird. Sie können im Gegenteil durchaus als komfortabler und funktionaler Wohnraum dienen. Auch die Verwendung regenerativer Energiequellen wie der Solarenergie ist unter den Bedingungen einer nördlich gelegenen Stadt wie Sankt Petersburg realisierbar. Die durchgeführten Berechnungen zeigen, dass eine Sanierung der russischen Wohnbauten der ersten Periode des industriellen Bauens durchaus lohnenswert sein kann, insbesondere wenn man die Entwicklung der Energiepreise betrachtet. In seiner energieeffizientesten Form (“Passivhaus”) bringt eine Sanierung eine Reduzierung des Endenergiebedarfs von bis zu 90 % im Vergleich zum Bestandsgebäude mit sich. Development of plans for retrofitting Russian housing, taking into account European competences for increasing its energy efficiency. There are various options for retrofitting Russian prefabricated concrete‐slab buildings of the first period of industrial construction, so‐called khrushchevki, with the object of bringing them up to European standards of thermal insulation technology. In the given case the basis of calculations was the German EnEV 2007 (Building Energy Conservation Ordinance). The analysis of sample building data opened up a large range of possibilities for increasing its energy efficiency. For instance, calculations ascertained that relatively inexpensive methods of enhancing a building’s thermal insulation can achieve a significant decrease in energy consumption for heating. In addition, this thesis analyzes possible variations of retrofitting and reconstruction using different types of materials and heating systems. The results clearly illustrate that residential houses e.g. type series 1‐507 have a future as comfortable and functional housing space. In fact, and in contrast to common prejudices, their “fate” is far from hopeless. Even the climatic circumstances of a northern city such as St. Petersburg do not preclude the use of alternative energy sources such as solar energy. On the contrary, it is a conceivable method of support for heating systems. In summary, the investigations show that the retrofitting of prefabricated concrete‐slab buildings of the first construction period is a sensible project, especially when taking into account the further development of fossil energy prices. In its most sophisticated form (the passive house), retrofitting will result in energy savings of up to 90 %.     

Three-dimensional imaging with simultaneous reproduction of two image elements in one display pixel by linearization of intensity ratio of two images formed by any physical gear

Full spatial resolution in stereo image is reached if each (left and right) view of a three-dimensional scene is reproduced by all pixels of the display matrix. It is attractive for this purpose to simultaneously reproduce two image resolvable elements (corresponding to image elements of left and right views) in one display pixel. This paper shows how information-dependent linearization of the optical intensity ratio of left and right image elements (whose sum is submitted in the form of common optical intensity on the input of the display pixel) can be used to present corresponding elements separately in left and right observation windows. Such a linearization principle is valid regardless of the concrete physical gear of optical separation and demonstrated on the examples of optical separators on the basis of polarization, spectral, diffractive, and real amplitude modulation of light.     

Strength and creep of structural materials based on intermetallic compound NiAl

The effect of thin tungsten and molybdenum layers, which were applied onto powder particles of intermetallic compound NiAl or its alloys with Hf and Nb before their pressing, on the hot strength and short-time creep strength of compact samples obtained from such granules has been studied. Such materials are proposed to be called composite materials (CM) with a honeycomb structure. Miniature samples in the form of small cylinders 5 mm in diameter and 5–8 mm in height were tested for compression at 1000–1300°C in air and for creep upon compression at 1050, 1110 and 1210°C in a vacuum. Alloying NiAl with hafnium or niobium increases the hot strength of the alloys by a factor of 1.4–3.7; the formation of honeycomb structure increases this characteristic by a factor of 1.6–3.6 at 1000°C; with increasing test temperature to 1300°C, the effect of solid-solution strengthening decreases to values typical of pure NiAl (σ_y = 7–12 MPa), and the effect of the honeycomb structures increases to σ _y ^CM / σ _y ^NiAl 6–7 at σ _y ^CM = 50–80 MPa. The creep strength characteristics of the CM σ _1% ^h/y and σ _10% ^h/y at all test temperatures are higher by a factor of 1.5–2.4 than those of NiAl and its alloy with Hf; they are as high as σ _1% ^h/1210 = 40.4 MPa and σ _10% ^h/1210 = 61.3 MPa for the NiAl + W(1 μm) CM and σ _1% ^h/1210 = 17.7 MPa and σ _10% ^h/1210 = 26.3 MPa for NiAl. For the composite material with a honeycomb structure, the attained gain in the working temperature relative that of the nonstrengthened NiAl is ～ 160 K.     

Analysis of the Deformation Process in Ni<Subscript>3</Subscript>(Al,Fe) Intermetallic under Longitudinal Bending

The structure and magnetic properties of an Ni₃(Al, Fe) single crystal after high-temperature rolling deformation have been studied. It has been shown that high-temperature rolling deformation induces longitudinal bending in Ni₃(Al, Fe), which is accompanied by the nonuniform distribution of stresses along the length of the sample. It has been found that longitudinal bending leads to change in either the mechanical or physical properties of the metal. Dynamic recrystallization has been found to occur at high degrees of deformation (starting at 40%). Local change in the distance between nickel and aluminum atoms, as well as the chemical composition, that takes place in the bending zones (distortions) of a crystal lattice of Ni3Al intermetallic compound is accompanied by change in the saturation magnetization and Curie temperature.