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Studies of hyper-arid sites contribute to our understanding on how life adapted to extreme conditions. They are often used to further deduce implications for extraterrestrial biology by the so-called analogue site-approach. The Atacama Desert, Chile, is one of the most prominent analogue sites despite its neighboring productive ecosystems due to its hyper-aridity and geochemical features resembling Martian environments. We hypothesize that many drivers of extremophile life in analogue sites are only mistakenly attributed to aridity alone, thus obscuring a clear view of the far more complex process interactions originating in nearby earthly ecosystems. To test this, we investigated 54 soil profiles up to 60 cm of soil depth along of four transects in the Atacama Desert, either running parallel (S-N) or perpendicular (W-E) to the Andes. Our objective was to reveal the processes controlling the formation of soil organic carbon (SOC) as the most reliable proxy for microbial life in order to understand the boundary conditions of life in extreme habitats. Further, we aimed at identifying analogue sites as uncompromised as possible by external influences of for example, vegetated or marine ecosystems. We found a mixture of influences driving habitable conditions on gradients perpendicular to the Andes, for example, fog and precipitation scavenging caused by altitudinal variations and differing proximity to the Pacific Ocean, while transects parallel to the Andes were much less biased by external factors. Our results show that studies on life under extreme conditions should clarify the explanatory strength of the investigated factors by a gradient study approach.

Product developers are faced with the challenge of covering an ever-increasing external variety with as little internal variety as possible. Modular product architectures offer one way of resolving the challenge. They have an impact on all life phases and on economic targets. These effects are represented in the Impact Model of Modular Product Families. A large number of modularization methods can be found in the literature. The modularization methods consist of different activities: decomposition of product, analysis and revision of components, and reintegration to modules. Module drivers play a major role in reintegration, as they determine which components together form a module. It is not yet clear what effects different modularization methods involving different module drivers have on economic targets. For this reason, the module drivers are examined in their role as levers of modularity and integrated into the Impact Model via access points. By documenting the results in a specially developed uniform method step description and the Impact Model, we enable the selection of modularization methods with regard to their economic impact. The introduction is followed by the state of research. In Sec.3, the research problem and the research approach are presented. In Sec.4, the generic method step description is applied to seven modularization methods. Based thereon, the modularization methods are compared with each other with regard to their addressed economic objectives. In an explanatory example, the method selection made possible by this is presented. Finally, the results are discussed and an outlook is given.

In the frame of LEMON project (Lidar Emitter and Multi-species greenhouse gases Observation iNstrument - European Union's Horizon 2020 research and innovation program, GA n°821868), we are developing a multi-species differential absorption Lidar (DIAL). The goal is to benefit from innovative technological developments in terms of optical emitter, spectral reference, to be able to address H2O and its isotope HDO at 1982 nm, CO2 at 2051 nm, and potentially CH4 at 2290 nm, for future ground-based range-resolved DIAL sensing, and with the prospect of future airborne integrated-path DIAL (IPDA). The infrared emitter is based on the combination of two specific, patented, no-seeder Nested Cavity OPOs (NesCOPOs) coupled to a single optical parametric amplifier (OPA) line for high energy pulses generation. Specific developments are also pursued on the frequency reference for the emitter, which is planned to be provided by a GPS referenced frequency comb against which the emitter output pulses can be heterodyned. Besides the instrument design, specific tests experiments have been carried out, covering a wide panel of activities: radiation testing of some critical components to assess the potential of some key components for future space applications, emitter and frequency reference testing, preliminary DIAL tests with laboratory test-beds and comparison with specific in-situ calibration instruments as well as additional innovative techniques evaluation for the emitter. The final instrument design was carried out and the sub-units are now being built., QC 20230831

In Sweden, the local schoolboard has the ultimate responsibility for school quality and student knowledge development, and is held responsible if the expected outcomes are not met. Assisting the board is the superintendent who is the Chief Executive Officer. The aim of the study is to investigate the board’s relation to and expectations of the superintendent, and this article is a result of a national investigation in which all schoolboard chairs were surveyed. Two main questions were addressed: 1) what expectations does the local schoolboard have of the superintendent, both in general and in relation to student achievements and 2) which tasks are the superintendents expected to prioritise in carrying out their work? Data have been collected through a web-based survey using both structured and open-ended questions. The results show that the schoolboards’ strongest expectations placed on superintendents are to execute the leadership mission followed by managing the organisation within allocated budget frames. Responsibilities for academic outcomes have a lower ranking. Superintendents have many opportunities to influence the schoolboards’ decisions and thereby affect which goals they should prioritise in the local school organisation. The superintendent is an invisible ruler who in the chain of governance occupies the best position to influence both the schoolboard’s acting policy and the schools’ acting practice. By being aware of the existing asymmetric distribution of power, the schoolboard has the opportunity to exercise control over its official whose legal responsibility is to assist its members in their decision makings.

Airborne wind energy systems convert wind energy into electricity using tethered flying devices, typically flexible kites or aircraft. Replacing the tower and foundation of conventional wind turbines can substantially reduce the material use and, consequently, the cost of energy, while providing access to wind at higher altitudes. Because the flight operation of tethered devices can be adjusted to a varying wind resource, the energy availability increases in comparison to conventional wind turbines. Ultimately, this represents a rich topic for the study of real-time optimal control strategies that must function robustly in a spatiotemporally varying environment. With all of the opportunities that airborne wind energy systems bring, however, there are also a host of challenges, particularly those relating to robustness in extreme operating conditions and launching/landing the system (especially in the absence of wind). Thus, airborne wind energy systems can be viewed as a control system designer’s paradise or nightmare, depending on one’s perspective. This survey article explores insights from the development and experimental deployment of control systems for airborne wind energy platforms over approximately the past two decades, highlighting both the optimal control approaches that have been used to extract the maximal amount of power from tethered systems and the robust modal control approaches that have been used to achieve reliable launch, landing, and extreme wind operation. This survey will detail several of the many prototypes that have been deployed over the last decade and will discuss future directions of airborne wind energy technology as well as its nascent adoption in other domains, such as ocean energy., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Wind Energy

Airborne wind energy (AWE) systems are tethered flying devices that harvest wind resources at higher altitudes, which are not accessible to conventional wind turbines. To become a viable alternative to other renewable energy technologies, AWE systems are required to fly reliably and autonomously for long periods of time while being exposed to atmospheric turbulence and wind gusts. In this context, the present paper proposes a three-step methodology to improve the resilience of an existing baseline control system toward these environmental disturbances. In the first step, upset conditions are systematically generated that lead to a failure of the control system using the subset simulation method. In the second step, the generated conditions are used to synthesize a surrogate model that can be used to predict upsets beforehand. In the final step an avoidance maneuver is designed that keeps the AWE system operational while minimizing the impact of the maneuver on the average pumping cycle power. The feasibility of the methodology is demonstrated on the example of tether rupture during pumping cycle operation. As an additional contribution a novel transition strategy from retraction to traction phase is presented that can reduce the probability of tether rupture significantly., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Wind Energy

Airborne wind energy (AWE) is a novel technology that aims at accessing wind resources at higher altitudes which cannot be reached with conventional wind turbines. This technological challenge is accomplished using tethered aircraft or kites in combination with either onboard or ground-based generators. In the former case, the kinetic energy of the air flow is transformed into electricity and transmitted via a conductive cable to the ground. In the latter case, the aerodynamic force of the aircraft or kite is translated into tether tension. The pulling force uncoils the tether from a drum which turns a generator and hence transforms the mechanical torque into electrical power on the ground. In this case two operational modes are required: In the first mode, the tether is reeled out until the maximum length is reached. It follows a reeling in phase where the aircraft or kite glides back towards the ground station and a fraction of the generated power is used to wind the tether again onto the drum of the winch. The cycle restarts as soon as the minimum tether length is reached. These two modes combined constitute a so-called pumping cycle. Reliability is a key system property that will decide over the success of AWE as a commercially feasible technology. To reach this goal, a well designed control system is required that can achieve the nominal control objectives as well as handle disturbances such as atmospheric turbulence and mismatches between the model used for the controller derivation and the real plant. In light of these challenges, the present work tries to make a contribution to bring AWE closer to commercial success. More specifically, a workflow to design a modular control architecture for a rigid wing AWE system operated in pumping cycle mode is presented. The thesis introduces models of different fidelity that are either directly used for the controller synthesis or in order to verify if the designed controller is able to meet its objectives. A quasi-stat, Wind Energy

In this paper, we present the design and computational model of a representative multi-megawatt airborne wind energy (AWE) system, together with a simulation framework that accounts for the flight dynamics of the fixed-wing aircraft and the sagging of the tether, combining this with flight control and optimisation strategies to derive the power curve of the system. The computational model is based on a point mass approximation of the aircraft, a discretisation of the tether by five elastic segments and a rotational degree of freedom of the winch. The aircraft has a wing surface area of 150 m2 and is operated in pumping cycles, alternating between crosswind flight manoeuvres during reel out of the tether, and rapid decent towards the ground station during reel in. To maximise the net cycle power, we keep the design parameters of the aircraft constant, while tuning the operational and controller parameters for different wind speeds and given contraints. We find that the presented design can generate a net cycle power of up to 3.8 megawatts., Wind Energy