1,235 research outputs found
Relying on storage or ICT? How to maintain low voltage grids' stability with an increasing feed-in of fluctuating renewable energy sources
Since the beginning of the new century our electricity system is changing rapidly. Distributed energy resources, such as wind or solar energies are becoming more and more important. These energies are producing fluctuating electricity, which is fed into low voltage distribution grids. The resulting volatility complicates the exact balancing of demand and supply. These changes can lead to distribution grid instabilities, damages of electronic devices or even power outages and might therefore end in deadweight losses affecting all electricity users. A concept to tackle this challenge is matching demand with supply in real-time, which is known as smart grids. In this study, we focus on two smart grids' key components: decentralized electricity storages and smart meters. The aim of this study is to provide new insights concerning the low diffusion of smart meters and decentralized electricity storages and to examine whether we are facing situations of positive externalities. During our study we conducted eight in-depth expert interviews. Our findings show that the diffusion of smart meters as well as decentralized electricity storages is widely seen as beneficial to society. This study identifies the most important stakeholders and various related private costs and benefits. As private benefits are numerous but widely distributed among distinct players, we argue that we face situations of positive externalities and thus societal desirable actions are omitted. We identify and discuss measures to foster diffusion of the two studied smart grid key components. Surprisingly, we find that direct interventions like subsidies are mostly not seen as appropriate even by experts from industries that would directly benefit from them. As the most important point, we identified well-designed and clearly defined regulatory and legal frameworks that are free of contradictions. --smart meter,decentralized electricity storage,smart grid,externality
PERVASIVE COMPUTING TO ENHANCE SPORT PERFORMANCE
The integration of modem sensor-, information-and communication technologies provides new means for developing systems to acquire data in -training and competition. Various sensors and devices are incorporated into the sport equipment or attached to the athlete. Mobile computers acquire and present the data recorded, other systems use telemetric methods to transmit the data acquired to receiving stations, which then process and adequately present them. Portable devices, which are not bound to laboratory conditions are particularly useful. Systems of that kind have been developed for table tennis and rowing. In the example of table tennis a microcontroller based solution for analysing service techniques is presented. In the case of rowing the system was developed for giving feedback both during on water and ergometer rowing
COMPARISON OF FOOT-STRETCHER FORCE PROFILES BETWEEN ON-WATER AND ERGOMETER ROWING
The purpose of this study was to compare the reaction forces at the foot stretcher of a Concept2 ergometer with and without slides to those of the boat in single scull rowing. Four male elite rowers were tested at rates of 20 and 30 strokes per minute on the ergometer with and without slides as well as in a single scull. The coefficient of multiple determination showed a high consistency about five time-normalised successive strokes in all conditions (about 0.99). Cross-correlation calculations between on-water force curves and force curves obtained under both ergometer conditions showed higher similarities for the ergometer on slides
A COMPARISON OF PLANTAR PRESSURES BETWEEN TWO DIFFERENT PLAYING SURFACES IN TENNIS
The purpose of this study was to compare two different playing surfaces in tennis – clay vs hard-court (OptiCourt) – in order get more insight on the influence of the effect of surface on load. Eight male tennis players performed two types of tennis specific
motions. Inside plantar pressure was measured for the right foot during these movements. Higher maximum forces could be observed for the OptiCourt for the baseline play. In more detail, maximum force, peak and mean pressure were higher for the heel
region on the hard-court. Higher values were found on clay for the hallux and lesser toe region. These results are in agreement with those of previous studies as they give evidence that playing surface affects loading in tennis
Continuous Synthesis of Oxymethylene Ether Fuels from Dimethyl Ether in a Heterogeneously Catalyzed Liquid Phase Process
Oxymethylene ethers (OME) are an attractive alternative to fossil diesel fuel due to strongly reduced harmful emissions. An anhydrous, liquid phase production process based on dimethyl ether (DME) has been elaborated, which offers high selectivity and economic advantages. A catalyst screening for the reaction of DME with trioxane has been carried out. Highly active catalysts could be identified and further insight into the relationship between catalyst properties and catalytic performance could be gained. Furthermore, production in a continuous process could be realized, disclosing the influence of kinetics on OME formation and enabling a better understanding of the reaction mechanism
ANALYSIS OF METHODS FOR ASSESSING THE AIMING PROCESS IN BIATHLON SHOOTING
In rifle shooting disciplines coaches and athletes are interested in the motion of the rifle just before and immediately after shooting. Normally, commercial laser systems (e.g. Noptel, Finland) are used to measure and store the hit point of the shot and the on-target trajectory of the alignment of the weapon. A major drawback of this method lies in the necessity of attaching the laser device to the rifle. The purpose of this study was to analyse the usefulness of a video-based system developed by Baca & Kornfeind (2006), which is able to track the 2D-movement of the muzzle of the weapon automatically. The results show considerable correspondence of the on-target-trajectory and the 2D-movement of the muzzle, in particular in vertical direction. However, translation movements of the shoulder during aiming, which are rather difficult to diagnose, may cause differences in the horizontal plane
In the Mood for Risk? A Random-Assignment Experiment Addressing the Effects of Moods on Risk Preferences
Recent discussions in decision sciences and behavioral economics stress the potential impact of affect on decision outcomes. In the present study, we conducted random-assignment experiments (N = 253) to investigate whether affect can cause temporary fluctuations in risk preferences. In particular, we employed film clips to vary the valence (positive / negative) and arousal level (low / high) of the affective states of student participants; following this, we elicited and observed risk preferences by asking the participants to make choi
Functional Characterization of Colon-Cancer-Associated Variants in ADAM17 Affecting the Catalytic Domain
Although extensively investigated, cancer is still one of the most devastating and lethal diseases in the modern world. Among different types, colorectal cancer (CRC) is most prevalent and mortal, making it an important subject of research. The metalloprotease ADAM17 has been implicated in the development of CRC due to its involvement in signaling pathways related to inflammation and cell proliferation. ADAM17 is capable of releasing membrane-bound proteins from the cell surface in a process called shedding. A deficiency of ADAM17 activity has been previously shown to have protective effects against CRC in mice, while an upregulation of ADAM17 activity is suspected to facilitate tumor development. In this study, we characterize ADAM17 variants found in tissue samples of cancer patients in overexpression studies. We here focus on point mutations identified within the catalytic domain of ADAM17 and could show a functional dysregulation of the CRC-associated variants. Since the catalytic domain of ADAM17 is the only region structurally determined by crystallography, we study the effect of each point mutation not only to learn more about the role of ADAM17 in cancer, but also to investigate the structure-function relationships of the metalloprotease
The Impact of Endogenous Motivations on Adoption of IT-Enabled Services: The Case of Transformative Services in the Energy Sector
Transformative services represent a crucial topic in future service research. Particularly in the energy sector, consumer adoption of transformativeoften IT-enabledservices is essential to increased environmental sustainability. As adopting these services increases both individual and collective well-being, research has to delve more deeply into the origins of consumers' motivations. For this reason, this study aims at augmenting the understanding of how different types of motivation determine consumers' intention to adopt transformative services. The proposed model integrates the theory of planned behavior and the self-determination theory and is tested with survey data gathered from 462 users and 537 nonusers of home energy management services. Results indicate that consumers' motivations are major direct determinants of intentions to adopt. While this finding notably holds when consumers perceive the adoption as self-determined and internalize associated values such as environmentalism, motivations based on external rewards and feelings of compulsion matter to a lesser extent. A comparison of users and nonusers reveals important differences in motivation, in particular that extrinsic motivations tend to be more relevant for nonusers than for users
Integration of residential distributed generators and heat pumps into the low voltage grid from a voltage level perspective
In context of combating climate change, carbon saving goals are defined on European
level. One effect of this is the increased installation of photovoltaic, heat pump and combined
heat and power systems on low voltage distribution grids. As the distribution grid
was not designed to handle this quantity of distributed generators and large loads, there
are undesirable influences. The voltage level is identified as the main issue in low voltage
grids. From the point of view of a manufacturer of such devices the influence on possible
connections to the low voltage grid and necessary measures are of interest. The characteristic
voltage influence of combined-heat-and-power, heat pump and photovoltaic systems is
evaluated. In order to quantify the influence, a 2020 penetration scenario of these devices
is developed using market expectation data. It is shown that different grids show violations
of the voltage limits according to EN 50160 and measures for voltage control are therefore
necessary in order to integrate the anticipated number of appliances. A range of measures
are evaluated regarding effectiveness, system operator and end-user economics, comfort
and environmental influence. The measures are based on grid operator equipment or enduser
appliances.
Battery storage based measures are identified as effective but very expensive compared
to other solutions. The most cost efficient measure is the installation of on-load
tap-changers at the low voltage transformers. Demand side management of heat pumps
can be effective under certain circumstances but end-user comfort is endangered here.
Considering the total economics, demand side management is more expensive than the
use of on-load tap changers. From a manufacturer perspective there are no additional
requirements for end-user appliances identified for voltage control on low voltage grids.
Connection restrictions and the grid planning process have to be reviewed in order to enable
cost efficient integration of the anticipated number of appliances in 2020. The results
are validated for increased generator penetrations in a ’maximum PV’ scenario
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