57 research outputs found
CONTRIBUTIONS OF CABIN RELATED AND GROUND OPERATION TECHNOLOGIES TOWARDS FLIGHTPATH 2050
Abstract The vision of the European Commission (EC) for 2050 is a 75% reduction in carbon dioxide (CO2) emissions per passenger kilometer relative to the capabilities of conventional aircraft in 2000. This paper focuses on airframe related contributions to a reduction of CO2 emissions in terms of structural changes of the cabin and fuselage design. Furthermore, thus far disregarded emissions during the on-block time at the airport are considered and ground operation enhancements are presented to reduce these. For the methodical approach several separate sensitivity analyses were performed to assess the CO2 impact of cabin and fuselage modifications, in terms of higher passenger density, reduced interior weight or usage of Carbon Fiber Reinforced Plastic (CFRP) for the fuselage structure, on the basis of a narrow-body medium-to-short haul reference aircraft. Moreover, the impact of electric taxiing and reduced onblock Auxiliary Power Unit (APU) running time are investigated. The result of the investigated airframe related technologies is a 6.5% CO2 emission reduction compared to the reference aircraft and a 6.2% reduction for the ATM and ground operation. However, the reduction potential of the presented strategies is insufficient to reach to target Flightpath 2050 goals solely from the investigated areas. Hence, further studies have to be conducted to improve cabin related designs and ground operation based processes to ensure the fulfillment of the released targets
Ownership of co-creation assets: driving B2B value propositions in the service economy
The benefits of specialization have been driving the rise of the service economy and pushing capability frontiers and economic growth. In service economies, almost any activity, asset, and skill can be bought on competitive markets, making it harder to build competitive advantage on any of those inputs. Against that background, the question emerges what constitutes sustainable value propositions of service providers. Drawing on an emerging stream of research on the non-ownership value of services, we argue that service providers create value by taking on ownership of service assets and thereby transform uncertainty of value creation into economic opportunities. In our view, service providers offer the essential value proposition of transforming their clients’ uncertainty downsides into opportunities related to assets such as vehicles, real estate, equipment and computing platforms. Clients benefit by delegating ownership of assets to the domain of a service provider. In turn, clients can focus their investment on their most promising assets. Service providers create sustainable competitive advantage by assuming ownership and excelling at the management of (a) unique physical assets, (b) unique intangible assets and (c) maintaining an appropriate architecture of social capital through customer relationships and business ecosystems
On the effect of multiple parallel nonlinear absorbers in palliation of torsional response of automotive drivetrain
Torsional vibrations transmitted from the engine to the drivetrain system induce a plethora of noise, vibration and harshness (NVH) concerns, such a transmission gear rattle and clutch in-cycle vibration, to name but a few. The main elements of these oscillations are variations in the inertial imbalance and the constituents of combustion power torque, collectively referred to as engine order vibration. To attenuate the effect of these transmitted vibrations and their oscillatory effects in the drive train system, a host of palliative measures are employed in practice, such as clutch pre-dampers, slipping discs, dual mass flywheel and others, all of which operate effectively over a narrow band of frequencies and have various unintended repercussions. These include increased powertrain inertia, installation package space and cost. This paper presents a numerical study of the use of multiple Nonlinear Energy Sinks (NES) as a means of attenuating the torsional oscillations for an extended frequency range and under transient vehicle manoeuvres. Frequency–Energy Plots (FEP) are used to obtain the nonlinear absorber parameters for multiple NES coupled in parallel to the clutch disc of a typical drivetrain configuration. The results obtained show significant reduction in the oscillations of the transmission input shaft, effective over a broad range of response frequencies. It is also noted that the targeted reduction of the acceleration amplitude of the input shaft requires significantly lower NES inertia, compared with the existing palliative measures
Phase-stable, multi-µJ femtosecond pulses from a repetition-rate tunable Ti:Sa-oscillator-seeded Yb-fiber amplifier
Recommended from our members
From relationships to partnerships - new forms of cooperation between buyer and seller
Kundenintegration und die Gestaltung von Geschäftsmodellen - Der Fall Siemens Cerberus ECO
Modal content analysis of hollow core Kagome fibers
We report on quantitative modal content measurements by S2 measurements in a Kagome type hollow core fiber depending on bending and in-coupling optimization. The higher order mode content could not be completely suppressed impacting important applications
Modal content measurements (S2) of negative curvature hollow-core photonic crystal fibers
We present modal content measurements (S2) of two different negative curvature hollow-core photonic crystal fibers: a kagome fiber and an ice cream cone fiber. Their sensitivity towards mode matching, bending and polarization is analyzed. For the kagome fiber, a higher order mode suppression of 17dB under optimal conditions was achieved, and for the ice cream cone fiber there was a suppression of up to 42dB. Polarization turned out to be a critical parameter for good higher order mode suppression in both fibers
Fabrication of longitudinally arbitrary shaped fiber tapers
We present our current results on the fabrication of arbitrary shaped fiber tapers on our tapering rig using a CO2-laser as heat source. Single mode excitation of multimode fibers as well as changing the fiber geometry in an LPG-like fashion is presented. It is shown that this setup allows for reproducible fabrication of single-mode excitation tapers to extract the fundamental mode (M2 < 1.1) from a 30 ÎĽm core having an NA of 0.09
- …