The influence of machining method of eccentric workpieces for accuracy and surface roughness

W pracy scharakteryzowano odmiany obróbki części klasy mimośrody. Określono wpływ odmian obróbki, a w szczególności sposobów ustalania mimośrodowości na dokładność i chropowatość toczonej powierzchni mimośrodowej. Analizowanym przykładem była obróbka wałka mimośrodowego skrzynki grzebieniowej na tokarce CNC TUG-56MN. Uzyskane wartości toczonego kształtująco mimośrodu z zastosowaniem tablic krzywych i kąta dyskretyzacji ΔC=2º oraz z zastosowaniem wielopozycyjnego przyrządu były prawie identyczne, natomiast wartość toczonego mimośrodu z użyciem podkładki pod jedną ze szczęk samocentrującego uchwytu trójszczękowego wyraźnie odbiegała od wymaganej wartości podanej w dokumentacji konstrukcyjnej. Chropowatość uzyskanych powierzchni określona średnią arytmetyczną rzędnych profilu Ra na obwodzie toczonego mimośrodu ulegała zmianom, w szczególności podczas toczenia z zastosowaniem tablic krzywych, co wynikało ze zmian geometrii ostrza w różnych położeniach kątowych obrabianego mimośrodu.The machining methods of eccentric workpieces were characterized in the paper. The impact of the machining method on the accuracy and surface roughness of the eccentric surface was determined. The analysed example was machining method of eccentric shaft for comb box on CNC lathe TUG-56MN. The received values for turned eccentric shape with using curves table and discretization angle ΔC=2º and using a multi-position production jig were almost identical, while the value for turned eccentric shape with use washer under one of the jaws of self-centering chuck are differed from the required value given in the construction documentation. The roughness of received surface determined by the average roughness Ra on the periphery of the turned eccentric shape is changed in particular with the use of curved tables as a result of changes in edge geometry at different angular positions of the machined eccentricity. The largest surface roughness of the eccentric occurred during turning using curved tables, while the smallest using a washer under one of the jaws of the self-centering lathe

Reduction of the vibration amplitudes of a harmonically excited sandwich beam with controllable core

abstractEN: e consider a theoretical analysis and experimental test of a sandwich beam, with a corelayer made of controllable material that can change its properties over time. We show thatthis dynamically excited beam can be sequentially controlled to obtain higher amplitudeattenuation and resistance to the amplitude growth in resonant ranges than when thesmart beam parameters are constant over time. Numerical simulations were performedto study the possibility of shifting beam vibration frequency towards ranges distant fromresonance. An experimental study on a layered beam consisting of two steel bars with apneumatically controlled core made of pressurized granular material was considered. Asimplified control was performed to detune the beam from the resonance frequenciesand reduce the vibrations by 30% in simulations and 10% in experiment.score: 45collation: 54-6

Bifunctional Peptide-Based Opioid Agonist–Nociceptin Antagonist Ligands for Dual Treatment of Acute and Neuropathic Pain

Herein, the opioid pharmacophore H-Dmt-d-Arg-Aba-β-Ala-NH₂ (<b>7</b>) was linked to peptide ligands for the nociceptin receptor. Combination of <b>7</b> and NOP ligands (e.g., H-Arg-Tyr-Tyr-Arg-Ile-Lys-NH₂) led to binding affinities in the low nanomolar domain. In vitro, the hybrids behaved as agonists at the opioid receptors and antagonists at the nociceptin receptor. Intravenous administration of hybrid <b>13a</b> (H-Dmt-d-Arg-Aba-β-Ala-Arg-Tyr-Tyr-Arg-Ile-Lys-NH₂) to mice resulted in potent and long lasting antinociception in the tail-flick test, indicating that <b>13a</b> was able to permeate the BBB. This was further supported by a cell-based BBB model. All hybrids alleviated allodynia and hyperalgesia in neuropathic pain models. Especially with respect to hyperalgesia, they showed to be more effective than the parent compounds. Hybrid <b>13a</b> did not result in significant respiratory depression, in contrast to an equipotent analgesic dose of morphine. These hybrids hence represent a promising avenue toward analgesics for the dual treatment of acute and neuropathic pain