Model-based Aeroservoelastic Design and Load Alleviation of Large Wind Turbine Blades

This paper presents an aeroservoelastic modeling approach for dynamic load alleviation in large wind turbines with trailing-edge aerodynamic surfaces. The tower, potentially on a moving base, and the rotating blades are modeled using geometrically non-linear composite beams, which are linearized around reference conditions with arbitrarily-large structural displacements. Time-domain aerodynamics are given by a linearized 3-D unsteady vortexlattice method and the resulting dynamic aeroelastic model is written in a state-space formulation suitable for model reductions and control synthesis. A linear model of a single blade is used to design a Linear-Quadratic-Gaussian regulator on its root-bending moments, which is finally shown to provide load reductions of about 20% in closed-loop on the full wind turbine non-linear aeroelastic model

Optimalisasi Pemberdayaan Masyarakat Desa Melalui Sinergi Program PUAP Dengan Desa Mandiri Pangan

Program pemberdayaan masyarakat yang bertujuan untuk mengentaskan kemiskinan di pedesaan pada prinsipnya memiliki banyak persamaan. Hal ini terlihat pada program PUAP dan Demapan. Adapun persamaannya antara lain : sama-sama berbasis desa, dilaksanakan oleh kelompok masyarakat, mendapatkan modal USAha pertanian dan non pertanian, terbentuknya lembaga keuangan mikro ditingkat desa, dan dibimbing oleh penyuluh dan tenaga pendamping. Dalam pelaksanaannya program tersebut masih banyak mengalami permasalahan dan untuk mengatasinya diperlukan koordinasi dengan cara mensinergikan program PUAP dengan Demapan. Sinergi dan integritasi kedua program mencakup beberapa aspek, yaitu : (1) diawali dengan sinergi data, pemilihan desa penerima program; (2) penataan internal kelembagaan program; (3) pemantapan pengembangan infrastruktur dengan sasaran akselerasi pengentasan kemiskinan; dan (4) antisipasi implementasi sinergi kedua program di lapangan. Dengan mengoptimalkan empat aspek tersebut, diharapkan akselerasi pembangunan pertanian dan ekonomi desa yang mengarah pada pengentasan kemiskinan dapat diwujudkan

Autonomous decision-making against induced seismicity in deep fluid injections

The rise in the frequency of anthropogenic earthquakes due to deep fluid injections is posing serious economic, societal, and legal challenges to geo-energy and waste-disposal projects. We propose an actuarial approach to mitigate this risk, first by defining an autonomous decision-making process based on an adaptive traffic light system (ATLS) to stop risky injections, and second by quantifying a "cost of public safety" based on the probability of an injection-well being abandoned. The ATLS underlying statistical model is first confirmed to be representative of injection-induced seismicity, with examples taken from past reservoir stimulation experiments (mostly from Enhanced Geothermal Systems, EGS). Then the decision strategy is formalized: Being integrable, the model yields a closed-form ATLS solution that maps a risk-based safety standard or norm to an earthquake magnitude not to exceed during stimulation. Finally, the EGS levelized cost of electricity (LCOE) is reformulated in terms of null expectation, with the cost of abandoned injection-well implemented. We find that the price increase to mitigate the increased seismic risk in populated areas can counterbalance the heat credit. However this "public safety cost" disappears if buildings are based on earthquake-resistant designs or if a more relaxed risk safety standard or norm is chosen.Comment: 8 pages, 4 figures, conference (International Symposium on Energy Geotechnics, 26-28 September 2018, Lausanne, Switzerland

Single-collision scattering of keV-energy Kr ions off a polycrystalline Cu surface

In the keV-energy regime, the scattering of krypton ions off a copper sample has been studied. In addition to the broad energy spectrum arising from multiple-collision scattering, the energy distributions of the backscattered ions exhibit prominent peaks at energies where single-collision (SC) scattering peaks are expected. Such SC peaks were shown to be absent in Sn – Mo/Ru scattering, systems of similar mass ratio and thus similar kinetics. The present Kr on Cu results allow for a comparison to a simulation package as SRIM. An important difference found between the present experiment and the predictions of SRIM is that the SC contribution is observed to decrease with scattering angle, whereas SRIM predicts this contribution to be constant. The intensity of the experimental SC peaks, though much weaker than in the SRIM simulations, may be used as markers to improve SRIM in its description of low-energy heavy particle scattering off surfaces

Ultrafast quenching of ring closure in molecular switches, self-assembled on gold nanoparticles

We report the ultrafast quenching of the ring-closure reaction in BTE-based photochromic switches self-assembled on gold nanoparticles. The photoinduced population dynamics of the switches reveals that the electronic states of the switch molecules are strongly mixed with the states of the gold particles.</p