Suche
Anzeige der Dokumente 211-220 von 1142
Aufsatz
How Do Gaining and Losing Streams React to the Combined Effects of Climate Change and Pumping in the Gharehsoo River Basin, Iran?
(2020-03-18)
Projections of potential impacts of climate change and groundwater abstraction on gaining and losing streams, particularly in ephemeral river basins exhibiting sporadic and intricate flux exchanges, have remained largely unexplored. To fill this gap, we propose a promising modeling scheme based on the new fully integrated hydrological model SWAT‐MODFLOW‐NWT, calibrated and validated for 1978–2012, to quantify the intertwined surface‐groundwater interactions under a conjuncture of three climatic emission scenarios ...
Aufsatz
Self-referencing circular dichroism ion yield measurements for improved statistics using femtosecond laser pulses
(2021-03-10)
The combination of circular dichroism with laser mass spectrometry via the measurement of ion yields is a powerful tool in chiral recognition, but the measured anisotropies are generally weak. The method presented in this contribution reduces the measurement error significantly. A common path optical setup generates a pair of counter-rotating laser foci in the interaction region of a time-of-flight spectrometer. As the space focus condition is fulfilled for both foci individually, this becomes a twin-peak ion source ...
Aufsatz
Emerging Development Pathways of Urban Livestock Production in Rapidly Growing West Africa Cities
(2016-11-19)
In this study, we try to capture the degree of specialization or integration, and of intensification or extensification, of (peri-) urban livestock production, along with the factors that influence such decisions and their impact on natural resource uses. A total of 181 and 187 structured questionnaires were completed in livestock-keeping households in Ouagadougou (Burkina Faso) and Tamale (Ghana). Categorical principal component and two-step cluster analysis were used to identify homogenous groups of livestock-keeping ...
Aufsatz
A Hybrid Optimization Method Combining Network Expansion Planning and Switching State Optimization
(2020-07-01)
Combining switching state optimization (SSO) and network expansion planning (NEP) in AC systems results in a mixed-integer non-linear optimization problem. Two methodically different solution approaches are mathematical programming and heuristic methods. In this paper, we develop a hybrid optimization method combining both methods to solve the combined optimization of SSO and NEP. The presented hybrid method applies a DC programming model as an initialization strategy to reduce the search space of the heuristic. A ...
Aufsatz
Stakeholder Influence on Sustainable Supply Chain Management: A Case Study of a German Apparel Frontrunner
(2021-10-12)
Although interest in green and sustainable supply chains has been growing for over a decade in the academic discourse, the textile industry still embraces numerous examples of non-sustainable behavior (i.e., environmental damage, poor working conditions, or modern slavery). While there is a general agreement that stakeholder pressure can lead to more sustainable SCs, a lot remains for a more differentiated stakeholder perspective in sustainable supply chain management (SSCM). Thus, this study aims for theory elaboration ...
Aufsatz
Willingness-to-Pay for District Heating from Renewables of Private Households in Germany
(2020-05-18)
Recent discussion about future energy production promotes the recovery of industrial heat as a potential solution to reduce carbon emissions. Experts call for an expansion of central heating by renewable energy systems to ensure a decarbonization of energy systems. In this context, district heating could play a significant role in city and district planning. Nonetheless, for private households, environmental aspects are only one factor amongst others as, e.g., capital costs, comfort and security. In this study, we ...
Aufsatz
A modification of a traditional Ethiopian maize store for solar powered ambient drying to reduce post-harvest losses
(2020-07-14)
A gombisa is a traditional Ethiopian structure widely used for maize storage over several months. It lacks adequate ventilation for timely moisture removal, which promotes mold development and aflatoxin production. In this study, a traditional gombisa was compared to one modified by installing a solar powered fan to provide forced ambient air ventilation during daytime. Approximately 900 kg of moist ear maize were loaded into each structure and samples from selected locations were weighed periodically to monitor ...
Aufsatz
Comparing different methods for the estimation of interbank intraday yield curves
(2020-01-16)
In this study, we compare three different models, namely, the Nelson–Siegel model (NSM), the Svensson model (SVM), and the Diebold–Li model (DLM), for the estimation of an intraday yield curve on the Italian interbank credit market e‐MID. Using a sample, which spans from October 2005 until March 2010, the first important finding is that all three models are highly suitable for the estimation of an intraday yield curve providing superior empirical results when compared with similar works on e‐MID. The second important ...
Aufsatz
Toward optimal probabilistic active learning using a Bayesian approach
(2021-05-04)
Gathering labeled data to train well-performing machine learning models is one of the critical challenges in many applications. Active learning aims at reducing the labeling costs by an efficient and effective allocation of costly labeling resources. In this article, we propose a decision-theoretic selection strategy that (1) directly optimizes the gain in misclassification error, and (2) uses a Bayesian approach by introducing a conjugate prior distribution to determine the class posterior to deal with uncertainties. ...
Aufsatz
Oxidation Reactions of the N-Heterocyclic Stannylenes [𝘰-C₆H₄ (NSi𝑡BuMe₂)]₂Sn and [{Fe(η⁵ -C₅H₄ -NSi𝑡BuMe₂)₂}Sn] with Sulfur, Selenium, and Diphenyl Diselenide
(2020-01-27)
The N‐heterocyclic stannylenes [{Fe(η$^5$‐C$_5$H$_4$‐NSi𝑡 BuMe$_2$)$_2$}Sn] (1 ) and [𝘰‐C$_6$H$_4$(NSi𝑡 BuMe$_2$)]$_2$Sn (2 ) were prepared in one‐pot reactions from SnCl$_2$, LiN(SiMe$_3$)$_2$, and the corresponding diamine, viz. [Fe(η$^5$‐C$_5$H$_4$‐NHSi𝑡 BuMe$_2$)$_2$] and 𝘰‐C$_6$H$_4$(NSiH𝘵 BuMe$_2$)$_2$, respectively. Oxidative addition reactions of 1 and 2 with S$_8$ and Se$_8$, respectively, afforded the corresponding 1,3,2,4‐dithiadistannetanes ((1 S$_2$), (2 S$_2$)), and 1,3,2,4‐diselenadistannetanes ...