Allocation of environmental burdens in dairy systems: Expanding a biophysical approach for application to larger meat-to-milk ratios

The dairy sector is urged to reduce environmental impacts, such as greenhouse gas (GHG) emissions. But dairy farms not only produce milk: surplus calves and culled cows also yield meat as co-product. To split environmental impacts between milk and meat, a biophysical allocation method proposed by the International Dairy Federation (IDF) is currently used. Its applicability to farms with large meat-to-milk output ratios (beef-to-milk ratio, BMR) may be limited and lead to wrong conclusions when assessing GHG emissions and mitigation measures at farm level. To overcome these limitations, we developed a biophysical allocation approach based on the net energy requirement for milk and meat production according to internationally agreed energy requirements for dairy cows. Both the enhanced and the existing allocation methods were tested on an international dataset that included farms with a large range of BMR, as can be found in dual-purpose production systems or on farms with low milk productivity. The results from the international dataset reveal that the allocation factor does not substantially change for production systems with low BMR. For BMR up to 0.03 kg live weight (LW)/kg of fat- and protein-corrected milk (FPCM), the maximum deviation in the allocation factor between the two methods was 0.047. For larger BMR, the developed method still allocated relevant shares of emissions to meat while the standard approach did not. The developed method is less sensitive to shifts in BMR, especially for low-performing dairy farms. In addition, both methods were tested on a dataset of 46 Swiss dairy farms. By increasing the longevity of cows (one additional lactation), the impacts of altered BMR on the modelled GHG emissions and their allocation on milk and meat could be assessed. Increased longevity resulted in fewer cows to be replaced, decreased emissions from the rearing of replacement stock (-444 kg CO2-equivalents/cow/year) and lower meat output (-61 kg LW/cow/year), as fewer cows were culled. Consequently, a larger share of emissions was allocated to milk. While the standard biophysical allocation approach did not result in reduced GHG emissions per kg of milk (+0.002 kg CO2-equivalents/kg FPCM), the newly developed approach generated a modest (-0.022 kg CO2-equivalents/kg FPCM), although not significant reduction. The effects of GHG mitigation measures that affect BMR are thus represented more accurately than when applying the standard approach. Based on the presented data, we encourage the revision of currently used international standards for allocating environmental impacts to milk and meat

Modelling of Bicycle Manufacturing via Multi-criteria Mixed Integer Programming

AbstractSustainable manufacturing considers the economic, environmental and social dimensions as equally important. For any product, like the common bicycles, a holistic view on the different life cycle phases has to be taken in order to ensure that resources are utilised adequately. Preferences on the three dimensions might lead to different selections of materials, used equipment or required education for fulfilling the considered objectives.In a first approach, bicycle manufacturing alternatives are identified and modelled via bi-criteria mixed integer programming. The material usage is used to represent the economic dimension and the carbon dioxide equivalent is used to represent the environmental dimension. The computed supported efficient solutions provide reasonable trade-off solutions for the considered bicycle manufacturing problem

Multi-criteria decision making as a tool for sustainable product development : Benefits and obstacles

For developing sustainable products design engineers need to foresee diverse interrelations between a product's characteristics and its economic, social and environmental impacts. In order to support this complex task a wide range of design methods has been developed. Retrospective analytical methods like Life Cycle Sustainability Assessment (LCSA) require a large amount of information and are thus utilized when important design decisions are already made. Prospective methods are rather generic (e.g. checklists) and too broad to be helpful in concrete design decisions. In this paper, the integration of discrete decision trees with LCSA is proposed for shifting multi-criterial quantitative analysis to earlier development. On the basis of sustainability indicators Pareto-optimal decision-paths for given material- and process alternatives along the product lifecycle can be compared up-front. Resulting benefits and obstacles are illustrated by evaluating value creation options of a bicycle frame

Antioxidant generation during coffee roasting : a comparison and interpretation from three complementary assays

Coffee is a major source of dietary antioxidants; some are present in the green bean, whereas others are generated during roasting. However, there is no single accepted analytical method for their routine determination. This paper describes the adaption of three complementary assays (Folin-Ciocalteu (FC), ABTS and ORAC) for the routine assessment of antioxidant capacity of beverages, their validation, and use for determining the antioxidant capacities of extracts from coffee beans at different stages in the roasting process. All assays showed a progressive increase in antioxidant capacity during roasting to a light roast state, consistent with the production of melanoidins having a higher antioxidant effect than the degradation of CGAs. However, the three assays gave different numbers for the total antioxidant capacity of green beans relative to gallic acid (GA), although the range of values was much smaller when chlorogenic acid (CGA) was used as reference. Therefore, although all three assays indicated that there was an increase in antioxidant activity during coffee roasting, and the large differences in responses to GA and CGA illustrate their different sensitivities to different types of antioxidant molecule

The FCH2RAIL Project: A Demonstration of a Modular Fuel Cell Hybrid Power Pack

In this paper, the Horizon 2020 project FCH2RAIL is outlined. The project aims to develop a bi-modal propulsion system, which combines an overhead catenary powertrain and a hydrogen fuel cell battery electric hybrid system to enable operation on tracks with mixed electrification. A key element is the fuel cell hybrid power pack and its modularity. To enable a wide range of applications, a modularity definition process in terms of installed fuel cell power and battery size is carried out. Therefore, a methodology was developed to derive generic and well-suited fuel cell and battery block sizes. Hereby, a work flow is set up, which incorporates a longitudinal vehicle dynamic simulation and a fuel cell hybrid propulsion system model. Using statistical analysis, required block sizes in terms of power and energy content of the main powertrain components are derived. Afterwards, the evaluated component block size ranges are compared to market-available components. The results obtained with the developed algorithms were 17 kWh for the smallest defined battery block and 47 kW for the fuel cell block. These dimensions are well-covered by market-available components, which demonstrates the applicability of the proposed methodology

Virtually Coupled Train Sets - A Comprehensive Analysis

In the X2Rail-3 project of the Shift2Rail Joint Undertaking, a detailed virtual coupling concept is developed and analysed in an extensive theoretical framework. Based on the paradigm shift from absolute to relative braking distance, various operational scenarios and potential hazards are identified. According to these scenarios and the general functional architecture, the project provides a first definition of the system requirements, detailing both the virtual coupling components as well as the interfaces and interactions with external systems. The subsequent analysis shows that virtual coupling can enable multiple performance benefits for railway operation. Beside the significant increase in capacity through shorter headways and reduced coupling times, additional flexibility and robustness are gained with situationally appropriate, dynamic coupling manoeuvres with a free choice of vehicles. Moreover, virtual coupling can contribute to reducing costs and delays by replacing the mechanical coupler. Aiming for technology readiness level 3, the results of the project illustrate that the concept is feasible from a technological and operational point of view, highlighting the most critical implementation parts in sensors, control and communication. A two-stage implementation approach is proposed to facilitate the introduction of virtual coupling. This is based on a minimum-complexity first stage to introduce the core functionalities and a second stage with incremental implementation of additional virtual coupling functionalities to further improve the operation. This stepwise approach is also corroborated by the results of the impact analysis, which shows a reduced impact for the first stage. The impact analysis illustrates that the fundamental principle of the external systems remains untouched and a full rework is not required. This also implies that virtual coupling will not interfere with the progress of the European Train Control System (ETCS) development and deployment. Therefore, the X2Rail-3 virtual coupling concepts provides a feasible, non-disruptive solution for a more efficient railway transport

Technical feasibility analysis and introduction strategy of the virtually coupled train set concept

Todays railway network capacity is limited by constraints imposed by traditional train protection systems. A way to overcome those limitations, maximize the railway network performance and also increase the operational flexibility is presented by the Virtually Coupled Train Set (VCTS) concept. This paper evaluates the technical feasibility of this approach, that was developed and is further evaluated in the framework of the Shift2Rail (S2R) project X2Rail-3. The main functionality of virtually coupled train sets is achieved by replacing the mechanical coupler between two railway vehicles by an electronic (virtual) coupling link. This operational change requires a permanent vehicle-to-vehicle communication and precise distance measurement, while enabling much faster coupling and decoupling procedures, increased interoperability and the operation of trains with a headway below absolute braking distance. To evaluate the technical feasibility of the VCTS concept, a series of technical and operational subsystem have been identified and analyzed. Interviews with experts from a variety of VCTS linked topics have been conducted, to evaluate the state of the art and new developments for those subsystems. Subsequently, the capabilities of the subsystems have been compared with the requirements of the VCTS system. In addition, different mitigations to overcome possible obstacles have been identified and evaluated. As the result, the most critical technical aspects for the implementation and success of VCTS have been identified as the requirement of controllable, fast and accurate responding braking systems, the availability of suitable communication technologies and frequency bands, the need for highly-accurate measurement of distance, speed and acceleration and the fast detection and monitoring of train integrity. Considering those results, a qualitative roadmap for the future VCTS development and introduction strategy is derived

Mehrkriterielle lineare Optimierung mit Anwendungen in nachhaltiger Produktionstechnik

Multicriteria optimisation is concerned with optimising several objectives simultaneously. Assuming that all objectives are equally important but conflicting, we are interested in the set of nondominated points, i.e., the image set of solutions that cannot be improved in any objective without getting worse off in another one. This thesis comprises three parts. The first part considers the computation of nondominated vertices of multicriteria linear programs. We present a cutting plane algorithm for finding nondominated vertices based on enumerating the vertices of a weight space polyhedron and describe its implementation in PolySCIP, a solver for multicriteria optimisation problems which we developed as a part of this dissertation. The focus of the second part is on multicriteria integer programs. In this part we investigate a partitioning of the set of nondominated points given by the set of points whose projections remain nondominated if one of the objectives is discarded and the set of points whose projections become dominated if one of the objectives is discarded. We present characteristics of this partitioning and show that the first mentioned partition can be used as an approximation of the entire set of nondominated points. The third part of this thesis considers two real-world applications in the context of sustainable manufacturing. The first problem regards bicycle frame manufacturing via a bicriteria integer programming formulation for which the non-dominated points are computed via PolySCIP. The second problem considers a tricriteria assignment problem in the context of scenario analysis. We classify this problem, show its hardness, and compute the set of nondominated points as well a partitioning of the set of nondominated points for given real-world data via PolySCIP.Mehrkriterielle Optimierung befasst sich mit Optimierungsproblemen, bei denen mehrere in Konflikt stehende Zielfunktionen gleichzeitig optimiert werden. Unter der Annahme, dass alle Zielfunktionen gleichwertig sind, betrachten wir einen Bildpunkt als nicht-dominiert, sofern er in keiner Zielfunktion verbessert werden kann ohne sich in einer anderen Zielfunktion zu verschlechtern. In dieser Arbeit interessieren wir uns für die Menge der nicht-dominierten Punkte für ein gegebenes mehrkriterielles Optimierungsproblem. Diese Dissertation lässt sich in drei Teile gliedern. Der erste Teil beschäftigt sich mit dem Berechnen von nicht-dominierten Eckpunkten im Kontext mehrkriterieller linearer Programmierung. Nach einführenden Erläuterungen präsentieren wir einen Algorithmus, der auf der Enumeration von Eckpunkten eines Gewichtsraumpolyeders basiert. In diesem Zusammenhang beschreiben wir ebenfalls die zugehörige Implementation in PolySCIP, einem von uns entwickelten Löser für mehrkriterielle Optimierungsprobleme. Der zweite Teil dieser Arbeit beschäftigt sich mit mehrkriterieller ganzzahliger Programmierung. In diesem Teil untersuchen wir eine Partitionierung der nicht-dominierten Punkte in zwei Teilmengen. Die erste Partition beinhaltet alle nicht-dominierten Punkte, deren Projektion nicht-dominiert bleibt, sofern man eine Zielfunktion außer Betracht lässt. Die zweite Partition beinhaltet alle nicht-dominierten Punkte, deren Projektion dominiert wird, sofern man eine Zielfunktion außer Betracht lässt. Wir charakterisieren diese Partitionierung und zeigen, dass die erstgenannte Partition die Menge der nicht-dominierten Punkte approximiert. Der dritte Teil dieser Arbeit betrachtet zwei Anwendungen aus dem Bereich der nachhaltigen Produktion. Die erste Anwendung betrifft ein auf Fahrradrahmen bezogenes Produktionsproblem, welches als ganzzahliges Programm mit zwei Zielfunktionen modelliert wird. Für die gegebenen Instanzen berechnen wir die Menge der nicht-dominierten Punkte mittels PolySCIP und interpretieren die zugehörigen Resultate. Die zweite Anwendung betrifft ein Optimierungsproblem mit drei Zielfunktionen aus dem Bereich der Szenarioanalyse. Wir zeigen, dass es zur Klasse der NP-schweren Probleme gehört und berechnen die Menge der nicht-dominierten Punkte sowie die zugehörigen Partitionen für die gegebenen Instanzen ebenfalls mittels PolySCIP.DFG, SFB 1026, Sustainable Manufacturing - Globale Wertschöpfung nachhaltig gestalte

Computerchemische Studien organokatalytischer Reaktionen

Ziel dieser Arbeit ist es, durch Einsatz computerchemischer Methodik, Einblicke in den Verlauf und Ausgang stereoselektiver organokatalytischer Reaktionen zu erhalten. Besonderes Augenmerk wird auf die Beschreibung bis dato nicht literaturbekannter Reaktionsmechanismen und Vorhersagen über die Stereoselektivität der entsprechenden Reaktionen im Experiment gelegt. Die Methoden die in dieser Arbeit besprochen werden sind zum größten Teil quantenmechanische Methoden. Des weiteren wurden Methoden basierend auf Newtonscher Mechanik sowie auf Basis von Reaktionskinetik verwendet. Der erste Teil der Arbeit umfasst eine umfangreiche Studie über die Genauigkeit der zur Verfügung stehenden quantenmechanischen Methoden im Hinblick auf die Energiebarrieredifferenzen zwischen diastereomeren Überganszuständen. Als Referenzenergien wurden post-Hartree Fock ab initio Daten verwendet, die sich dadurch auszeichnen, dass sie, durch explizite Korrelation,systematisch bis zur Konvergenz der Ergebnisse erweiterbar sind. Es stellte sich heraus, dass Experimentaldaten sich nur bedingt als Referenz eignen, da schlechte Vorhersagen selten veröffentlicht werden, aber für die Beurteilung essentiell sind Es kann gezeigt werden, dass post-Hartree Fock ab initio Methoden bei systematischer Erweiterung früh zum Erreichen von Konvergenz in der Referenzenergie führen. Die Ergebnisse lassen sich mit den meisten Dichtefunktionaltheoriemethoden qualitativ reproduzieren. Um Energien quantitativ korrekt zu reproduzieren, sollten moderne dispersionskorrigierte DFT Methoden mit großem Basissatz verwendet werden. In vielen Fällen ist dann eine genaue Beschreibung von Strukturen und Energien der relevanten Übergangszustände auf einem Niveau möglich, dass zur quantitativen Vorhersage von Diastereomer- und Enantiomerverhältnissen ausreicht. Im zweiten Teil der Arbeit wurde der Reaktionsmechanismus der Organosilizium katalysierten diastereoselektiven 1,3-dipolare Cycloaddition zwischen Hydrazonen und Cyclopentadien anhand von DFT Modellreaktionen untersucht. Die Modellierung des Mechanismus legt eine Reaktion über Silizium-Kation-Hydrazonaddukte nahe. Man kann darauf schließen, dass potenziell katalytisch aktive Siliziumverbindungen eine gute Abgangsgruppe aufweisen sollten. Experimentelle Untersuchungen im Arbeitskreis konnten diese Vorhersage bestätigen. Ausgehend von der Modellreaktion wurden Voraussetzungen für einen potentiell enantioselektiven Katalysator abgeleitet. Im dritten Teil der Arbeit wurden autokatalytisch-organokatalytische Reaktionen untersucht. Ausgehend von einem literaturbekanntem Modell für autokatalytisch-metallkatalytische Reaktionen wurden realitätsnahe Modelle entwickelt, die autokatalytische Amplifikation in autokatalytisch-organokatalytischen Reaktionen erlauben. Ziel dieser Studie ist nötigen Voraussetzungen für autokatalytische Amplifikation zu beschreiben. Die entsprechenden Reaktionsnetzwerke wurden in einem Reaktionskinetikmodell beschrieben, welches durch schrittweise Integration der Ratengleichungen gelöst wurde. Aus den Modellen kann abgeleitet werden, dass sich Amplifikation in organo-autokatalytischen Reaktionen durch eine selektive Anreicherung des katalytisch aktiven Produktes der Reaktion erzielen lässt. Um das zu erreichen wird vorgeschlagen, di- oder oligomerisierbare Reaktionsprodukte zu verwenden. Während in den bisherigen Modellen die Bildung stabiler Heterodimere als nötige Grundlage angenommen wird, können wir zeigen, dass die Dimerbildung allein für enatioselektive Amplifikation ausreichen kann und auch Systeme die stabile Homodimere bilden potenziell die gewünschte Aktivität zeigen können. An Systemen, die die vorhergesagten Eigenschaften im Experiment aufweisen wird momentan weitergeforscht. Der vierte Teil der Arbeit befasst sich mit experimentellen und quantenmechanischen Untersuchungen an einer Aldoladditions-Reaktion, welche spontane Bildung von Enantiomerenüberschüssen aufweist. Ziel der Untersuchung war zum Einen, zu klären ob diese Reaktion eine Amplifikation von Enantioselektivität erlaubt, und zum Anderen die Gründe für das spontane Auftreten eines Enantiomerenüberschusses zu finden. Aus quantenmechanischen Untersuchungen zum Reaktionsmechanismus und Röntgenkristallstrukturuntersuchungen am Reaktionsprodukt lässt sich ableiten, dass im vorliegenden Fall Produktdimer-Katalyse allein nicht ausreicht um das beobachtete spontane Auftreten eines Enantiomerenüberschusses zu erklären. Die Auswertung der Kristallstrukturanalyse zeigt, dass die erwarteten Produkt-Produkt Wechselwirkung zwar vorhanden sind, sich aber im Kristall, und daher mit größter Wahrscheinlichkeit auch an der Kristalloberfläche deutlich von den Modellwechselwirkungen unterscheiden.The aim of this work is the application of computational chemical methods, in order to gain insight into the process and products of stereoselective organocatalytic reactions. Special attention is paid to the description of up-to-date literature unknown reactions and predictions of the stereoselectivity of the corresponding experimental reactions. The approaches discussed in this work are predominantly quantum mechanical methods. Newton mechanical methods (molecular mechanics) and reaction kinetics based methods were also applied. The first part of this work comprises a comprehensive assessment of accuracy of the available quantum mechanical methods in respect to the energy-barrier differences of pairs of diastereomeric transition states. Since energy differences below one kcal/mol can lead to qualitatively decisive differences in predicted product distributions, only methods allowing a smaller error than one kcal/mol can be looked upon as accurate. Post-Hartree Fock ab initio methods were used to generate accurate reference energies, as they can be systematically improved until their results converge. Experimental results proved to be a poor reference, since poorly predicted results are least likely to be published, but vital for the assessment process. We were able to show that the reference energies of post-Hartree Fock ab initio methods rapidly converge upon systematic improvement. The benchmark results are qualitatively reproducible with most density functional theory (DFT) methods. In order to reproduce the benchmark results quantitatively correctly, modern dispersion corrected DFT methods should be employed in combination with an extended basis set. In many cases, an accurate description of structures and energies of the transition states is possible on an adequate level for the quantitative prediction of enantiomer and diastereomer distributions. In the second part of this work, the reaction mechanism of the organo-silicon catalyzed diastereoselective 1,3-dipolar cycloadditions between hydrazones and cyclopentadiene is studied in a DFT model. According to the DFT study, a silicon cation catalyzed mechanism seems most likely. The modeling of the mechanism allows the conclusion that the reactions proceed via a silicon cation-hydrazone adduct. Concluding, potentially active silicon compounds should carry a good leaving group, as was confirmed by experimental studies in our group. Based on the model reaction, prerequisites for potential enantioselective catalysts were concluded. In the third part of this work, autocatalytic organo-catalytic reactions are studied. Starting from a literature known model for autocatalytic metal-catalytic reactions, realistic models that allow autocatalytic amplification in autocatalytic organocatalytic reactions are developed. The aim of this study is to describe the necessary prerequisites that result in autocatalytic amplification. The reaction networks were described by a reaction kinetic model, which was solved by stepwise integration of the rate equations. We conclude from the models studied that amplification in organo- and autocatalytic reaction systems can only be achieved by an effective accumulation of the catalytically active product. In order to comply, reactions that allow the formation of product dimers or oligomers are proposed to be employed. While preceding studies concluded that the formation of stable homodimers is necessary, we were able to show that the formation of any dimers can also be sufficient and that the formation of stable homodimers can also lead to enantiomeric amplification. It is possible that some literature known reactions that show only weak positive linear effects react according to the latter model. Research on systems with the predicted properties is being continued. The fourth part of this work aims at the experimental and quantum mechanical description of aldol reactions, which allow the spontaneous formation of enantiomeric excesses in experiments. The aim of the study is to clarify if this model reaction allows amplification of enatioselectivity and to find the driving force towards the spontaneous formation of enantiomeric excess. In the experimental approach, an amplification of an initial enantiomeric excess was observed in few cases, but can only be attributed to dissociative processes, which cannot be exploited synthetically. Quantum mechanical studies on the reaction mechanism and X-ray crystallographic studies allow the conclusion that in the current case, product dimer catalysis alone is not sufficient to explain the experimental finding of spontaneous occurrence of enantiomeric excesses. The crystallographic study showed that the proposed product-product interaction schemes are present, but significantly differ from the modeled structures. We can conclude that especially in oligomers, in crystals and on their surface, interactions differ significantly from the model system

Direktstromnutzung aus Erneuerbaren Energien zur Versorgung der Ladienfrastruktur von Akkumulator-Triebzügen.

Zunächst wird der Energiebedarf für alternative Antriebe im Streckennetz des deutschen SPNV simulationsbasiert abgeschätzt. Anhand von Beispielstrecken wird der Energiebedarf von Akkumulator-Triebzügen modelliert und der Leistungsbedarf der Ladeinfrastruktur sowie die Auswirkungen auf das öffentliche Stromnetz analysiert. Darauf basierend wird die Einbindung von Erneuerbaren Energien zur Versorgung der Ladeinfrastruktur mit einem Optimierungsansatz untersucht