Search results for "high"
showing 10 items of 25798 documents
Competition between chain scission and branching formation in the processing of high-density polyethylene: effect of processing parameters and of sta…
2009
Two samples of high-density polyethylene with different molecular weight were processed in a batch mixer and the rheological and structural properties were investigated. In particular, the effect of different processing parameters and the eventual presence of different stabilizers were evaluated. Actually, two reactions may occur during processing: branching/crosslinking or chain scission. The results indicate that when the processing conditions promote a scarce mobility of the macromolecular chains (lower temperatures, lower mixing speed, and higher molecular weight), branching is more favored than chain scission. On increasing the mobility of the chain (higher temperature, higher mixing s…
Impact of Separator Thickness on Temperature Distribution in Single Cell of Polymer Electrolyte Fuel Cell Operated at Higher Temperature of 90 °C and…
2022
The New Energy and Industry Technology Development Organization (NEDO) road map (Japan, 2017) has proposed that a polymer electrolyte fuel cell (PEFC) system, which operates at a temperature of 90 °C and 100 °C, be applied for stationary and mobility usage, respectively. This study suggests using a thin polymer electrolyte membrane (PEM) and a thin gas diffusion layer (GDL), at the same time, to achieve better power-generation performance, at a higher temperature than usual. The focus of this paper is to clarify the effect of separator thickness on the distribution of temperature at the reaction surface (Treact), with the relative humidity (RH) of the supply gasses and initial operation tem…
An algorithm based on the PPC (Polynomial Parametric Curve) for designing horizontal highway alignments
2015
Criteria for geometric design of highway alignments have been studied in various researches so far, providing new methods, as alternative to traditional approaches. They can be useful for obtaining better solutions, characterized by high performances in terms of motion safety and comfort. In particular, continuous curvature alignments, based on polynomial functions, are highly consistent solutions with users' driving behaviour and vehicle trajectories. Moreover, alignment geometry optimization allows engineers to minimize dynamic effects on drivers with considerable advantages in terms of comfort and safety. This paper carries on the research of a previous study, in which a polynomial param…
Struttura galleggiante ad elevata stabilità (Floating structure with high stability)
2015
DESCRIZIONE GENERALE La struttura galleggiante innovativa è composta da diversi elementi modulari collegati fra loro. La composizione modulare della struttura consente di conferirle la lunghezza dettata dalle particolari esigenze da soddisfare. Tipiche applicazioni della struttura galleggiate innovativa sono i pontili, le passerelle pedonali o ciclabili su specchi d'acqua, e in generale le opere finalizzate a consentire lo spostamento di persone, merci e/o veicoli fra punti di uno specchio d'acqua (marino o lacustre) utilizzando strutture galleggianti. Ogni modulo, lungo 10-15 m, è tenuto a galla dalla spinta di Archimede sulle sue parti immerse (le carene), spinta che nella struttura innov…
The acute effects of different high-intensity conditioning activities on sprint performance differ between sprinters of different strength and power …
2021
The purpose of the present study was to examine the effect of different conditioning activities (CAs) on short-term increase in sprint performance. In twelve male sprinters (21.1+2.6 years, 100 m performance: 11.5+0.6 s) their body composition, half squat maximum strength, 100 m sprinting and countermovement jump performances were evaluated. The performance of a 50 m sprint (splits at 10 m, 30 m and 50 m) was evaluated before and 5, 10 and 15 min after four postactivation performance enhancement CAs on different occasions: [1] 3 sets x 4 s maximum isometric half squat (IHF), [2] 3 sets x 3 consecutive countermovement jumps (cCMJs), [3] 3 repetitions x 30 m overspeed sprinting (OVSP) and [4]…
Influence of the process parameters on the microstructure of a hardfacing coating elaborated by hot isostatic pressing
2019
Hot Isostatic Pressing elaboration of Norem02, an austenitic-ferritic hypereutectoid stainless steel, leads to the formation ofan austenitic matrix with a mixture of acicular M7C 3 and globular M23 C 6 carbides. The sintering tests, carried out by using an AISI304L container, showed that the final microstructure and the carbides’ distribution of the HIPed Norem02 are strongly influencedby the process parameters (heating and cooling rate, sintering time, holding temperature and pressure) and by the particles’ size,microstructure and phase distribution of the initial powder. The morphological, crystallographic and chemical analysis of the sinteredsamples were completed by comprehension of the…
New high-pressure phase and equation of state of Ce2Zr2O8
2012
In this paper we report a new high-pressure rhombohedral phase of Ce2Zr2O8 observed from high-pressure angle-dispersive x-ray diffraction and Raman spectroscopy studies up to nearly 12 GPa. The ambient-pressure cubic phase of Ce2Zr2O8 transforms to a rhombohedral structure beyond 5 GPa with a feeble distortion in the lattice. Pressure evolution of unit-cell volume showed a change in compressibility above 5 GPa. The unit-cell parameters of the high-pressure rhombohedral phase at 12.1 GPa are ah = 14.6791(3) {\AA}, ch = 17.9421(5) {\AA}, V = 3348.1(1) {\AA}3. The structure relation between the parent cubic (P2_13) and rhombohedral (P3_2) phases were obtained by group-subgroup relations. All t…
"Table 1" of "Charm-quark fragmentation fractions and production cross section at midrapidity in pp collisions at the LHC"
2022
Ratio of prompt open-charm hadrons H$_\mathrm{c}$ and inclusive $\mathrm{J}/\psi$ mesons over D$^0$-meson production cross section in pp collisions at $\sqrt{s} = 5.02$ TeV.
Azimuthal correlations of prompt D mesons with charged particles in pp and p–Pb collisions at √sNN = 5.02 TeV
2020
The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in pp collisions at √s = 5.02 TeV and p–Pb collisions at √sNN = 5.02 TeV with the ALICE detector at the LHC is reported. The D0D0, D+D+, and D∗+D∗+ mesons, together with their charge conjugates, were reconstructed at midrapidity in the transverse momentum interval 30.3 GeV/c and pseudorapidity |η|<0.8. The properties of the correlation peaks appearing in the near- and away-side regions (for Δφ≈0 and Δφ≈π, respectively) were extracted via a fit to the azimuthal correlation functions. The shape of the correlation functions and the near- and away-side peak features are found to be consistent in pp a…
Comparison of Post-Weld Treatment of High-Strength Steel Welded Joints in Medium Cycle Fatigue
2010
This paper presents a comparison of three post-weld treatments for fatigue life improvement of welded joints. The objective is to determine the most suitable post-weld treatment for implementation in mass production of certain crane components manufactured from very high-strength steel. The processes investigated are: burr grinding, TIG dressing and ultrasonic impact treatment. The focus of this investigation is on the so-called medium cycle area, i.e. 10 000-500 000 cycles and very high stress ranges. In this area of fatigue design, the use of very high strength steel becomes necessary, since the stress range can exceed the yield-strength of ordinary structural steel, especially when consi…