22 research outputs found
Analyze of RDF-production in Vietnam
A simplified RDF production was made, together with a waste characterization of MSW from Hanoi area. Three experiments were done, two with active aeration and one without. A high water content was determined at all RDF, which has a negative influence on the lower heating value and a saving-effect. A accumulation of the heating value to the higher class (>40mm), was not completely possible, also no complete transfer of mineral contents to the lower class (<10mm). The RDF reach in most cases the criteria for a fuel for different limit values, heavy metals, chloride and sulfur. An economic benefit could be possible with a surplus income by using RDF instead of coal (lignite), also by avoiding landfill gas and sell emission rights via CDM. More and detailed investigations seem to be necessary to confirm these results.:I. Index I
II. Abbreviations III
III. List of Tables IV
IV. Figures VII
V. Acknowledgements VIII
VI. Summary IX
1. Introduction 1
2. Materials and methods 3
2.1 Waste Composition Analyze 3
2.2 Sample analyze 4
2.2.1 Water Content 4
2.2.2 Size reduction 5
2.2.3 Carbon content 5
2.2.4 Chloride and Sulfur 7
2.2.5 Heavy metals 7
2.2.6 fossil and biogenic carbon 9
2.2.7 Ash content / Los of Ignition 11
2.3 biological Stabilization 11
2.3.1 Active Aeration 12
2.3.2 Passive aeration 12
2.4 Clean Development Mechanism 13
2.4.1 Kyoto Protocol 13
2.4.2 International emission trading 14
2.4.3 Clean Development Mechanism 15
2.4.4 Avoidance potential of emissions from waste through RDF production 22
2.5 Economic calculation 27
2.6 Comparison to the usage of primary energy sources 28
3. Results 30
3.1 Waste characterization 30
3.2 Mass Balance of RDF Production 33
3.3 Water content 34
3.3.1 Waste from Characterization 34
3.3.2 RDF 35
3.4 Heating value 36
3.4.1 Waste from Characterization 36
3.4.2 RDF 37
3.5 Heavy metals 38
3.5.1 Waste from Characterization 38
3.5.2 RDF 39
3.6 Chloride and Sulfur content 41
3.6.1 Waste from Characterization 41
3.6.2 RDF 42
3.7 Total carbon content 42
3.8 Biogenic / fossil carbon content / Ash 43
3.9 Methane avoidance potential 44
3.10 CO2e emission through RDF usage 45
3.11 Economic comparison 46
3.12 Comparison to coal 47
4. Discussion 48
4.1 1st Thesis 48
4.2 2nd Thesis 53
4.3 3rd Thesis 61
4.3.1 Mechanical requirements 62
4.3.2 Caloric requirements 63
4.3.3 Chemical requirements 64
4.4 4th Thesis 71
4.4.1 Environmental benefit 71
4.4.2 Economical benefit 74
5. Conclusion 77
References 79
Annex I - Tables I
Affidavit â Eidesstattliche ErklĂ€rung
Quantum phase transitions of a square-lattice Heisenberg antiferromagnet with two kinds of nearest-neighbor bonds: A high-order coupled-cluster treatment
We study the zero-temperature phase diagram and the low-lying excitations of a square-lattice spin-half Heisenberg antiferromagnet with two types of regularly distributed nearest-neighbor exchange bonds [J>0 (antiferromagnetic) and -â<J'<â] using the coupled cluster method (CCM) for high orders of approximation (up to LSUB8). We use a NeÂŽel model state as well as a helical model state as a starting point for the CCM calculations. We find a second-order transition from a phase with NeÂŽel order to a finite-gap quantum disorderedphase for sufficiently large antiferromagnetic exchange constants J'>0. For frustrating ferromagnetic couplings J'<0 we find indications that quantum fluctuations favor a first-order phase transition from the NeÂŽel order to a quantum helical state, by contrast with the corresponding second-order transition in the corresponding classical model. The results are compared to those of exact diagonalizations of finite systems (up to 32sites) and those of spin-wave and variational calculations. The CCM results agree well with the exact diagonalization data over the whole range of the parameters. The special case of J'=0, which is equivalent to the honeycomb lattice, is treated more closely
Electronic Quantum Coherence in Glycine Molecules Probed with Ultrashort X-ray Pulses in Real Time
Structural changes in nature and technology are driven by charge carrier
motion. A process such as charge-directed reactivity that can be operational in
radiobiology is more efficient, if energy transfer and charge motion proceeds
along well-defined quantum mechanical pathways keeping the coherence and
minimizing dissipation. The open question is: do long-lived electronic quantum
coherences exist in complex molecules? Here, we use x-rays to create and
monitor electronic wave packets in the amino acid glycine. The outgoing
photoelectron wave leaves behind a positive charge formed by a superposition of
quantum mechanical eigenstates. Delayed x-ray pulses track the induced
electronic coherence through the photoelectron emission from the sequential
double photoionization processes. The observed sinusoidal modulation of the
detected electron yield as a function of time clearly demonstrates that
electronic quantum coherence is preserved for at least 25 femtoseconds in this
molecule of biological relevance. The surviving coherence is detected via the
dominant sequential double ionization channel, which is found to exhibit a
phase shift as a function of the photoelectron energy. The experimental results
agree with advanced ab-initio simulations.Comment: 54 pages, 11 figure
Utilization of stabilized soil in landfill constructions
The thesis investigate the impact of different waste materials (gypsum, fly ash, sewage sludge) and peat together with zero-valent iron on the immobilization of arsenic from a chromate-zinc-arsenate (CZA) contaminated soil. The remediated soil should used as a secondary material for the vegetation layer of a landfill. The test was performed in a gravity column test with different sampling horizons (50cm, 100cm, 200cm). The layer with 50cm and 100 cm shows low arsenic concentrations. This thickness could reach the requirements of the EU landfill directive (1999/31/EC).The thesis shows promising result for gypsum-, peat-, sewage sludge- and only iron-treated soils, but with reservations. The arsenic concentration decreased, but mainly in the top and middle segment. For fly ash treated soils the arsenic concentration increased in all segments in comparison to a blank. Further studies for the iron- gypsum-, peat- and sewage sludge mixture are required, especially a field study under natural conditions.Validerat; 20101217 (root
Analyze of RDF-production in Vietnam
A simplified RDF production was made, together with a waste characterization of MSW from Hanoi area. Three experiments were done, two with active aeration and one without. A high water content was determined at all RDF, which has a negative influence on the lower heating value and a saving-effect. A accumulation of the heating value to the higher class (>40mm), was not completely possible, also no complete transfer of mineral contents to the lower class (<10mm). The RDF reach in most cases the criteria for a fuel for different limit values, heavy metals, chloride and sulfur. An economic benefit could be possible with a surplus income by using RDF instead of coal (lignite), also by avoiding landfill gas and sell emission rights via CDM. More and detailed investigations seem to be necessary to confirm these results.:I. Index I
II. Abbreviations III
III. List of Tables IV
IV. Figures VII
V. Acknowledgements VIII
VI. Summary IX
1. Introduction 1
2. Materials and methods 3
2.1 Waste Composition Analyze 3
2.2 Sample analyze 4
2.2.1 Water Content 4
2.2.2 Size reduction 5
2.2.3 Carbon content 5
2.2.4 Chloride and Sulfur 7
2.2.5 Heavy metals 7
2.2.6 fossil and biogenic carbon 9
2.2.7 Ash content / Los of Ignition 11
2.3 biological Stabilization 11
2.3.1 Active Aeration 12
2.3.2 Passive aeration 12
2.4 Clean Development Mechanism 13
2.4.1 Kyoto Protocol 13
2.4.2 International emission trading 14
2.4.3 Clean Development Mechanism 15
2.4.4 Avoidance potential of emissions from waste through RDF production 22
2.5 Economic calculation 27
2.6 Comparison to the usage of primary energy sources 28
3. Results 30
3.1 Waste characterization 30
3.2 Mass Balance of RDF Production 33
3.3 Water content 34
3.3.1 Waste from Characterization 34
3.3.2 RDF 35
3.4 Heating value 36
3.4.1 Waste from Characterization 36
3.4.2 RDF 37
3.5 Heavy metals 38
3.5.1 Waste from Characterization 38
3.5.2 RDF 39
3.6 Chloride and Sulfur content 41
3.6.1 Waste from Characterization 41
3.6.2 RDF 42
3.7 Total carbon content 42
3.8 Biogenic / fossil carbon content / Ash 43
3.9 Methane avoidance potential 44
3.10 CO2e emission through RDF usage 45
3.11 Economic comparison 46
3.12 Comparison to coal 47
4. Discussion 48
4.1 1st Thesis 48
4.2 2nd Thesis 53
4.3 3rd Thesis 61
4.3.1 Mechanical requirements 62
4.3.2 Caloric requirements 63
4.3.3 Chemical requirements 64
4.4 4th Thesis 71
4.4.1 Environmental benefit 71
4.4.2 Economical benefit 74
5. Conclusion 77
References 79
Annex I - Tables I
Affidavit â Eidesstattliche ErklĂ€rung
Analyze of RDF-production in Vietnam
A simplified RDF production was made, together with a waste characterization of MSW from Hanoi area. Three experiments were done, two with active aeration and one without. A high water content was determined at all RDF, which has a negative influence on the lower heating value and a saving-effect. A accumulation of the heating value to the higher class (>40mm), was not completely possible, also no complete transfer of mineral contents to the lower class (<10mm). The RDF reach in most cases the criteria for a fuel for different limit values, heavy metals, chloride and sulfur. An economic benefit could be possible with a surplus income by using RDF instead of coal (lignite), also by avoiding landfill gas and sell emission rights via CDM. More and detailed investigations seem to be necessary to confirm these results.:I. Index I
II. Abbreviations III
III. List of Tables IV
IV. Figures VII
V. Acknowledgements VIII
VI. Summary IX
1. Introduction 1
2. Materials and methods 3
2.1 Waste Composition Analyze 3
2.2 Sample analyze 4
2.2.1 Water Content 4
2.2.2 Size reduction 5
2.2.3 Carbon content 5
2.2.4 Chloride and Sulfur 7
2.2.5 Heavy metals 7
2.2.6 fossil and biogenic carbon 9
2.2.7 Ash content / Los of Ignition 11
2.3 biological Stabilization 11
2.3.1 Active Aeration 12
2.3.2 Passive aeration 12
2.4 Clean Development Mechanism 13
2.4.1 Kyoto Protocol 13
2.4.2 International emission trading 14
2.4.3 Clean Development Mechanism 15
2.4.4 Avoidance potential of emissions from waste through RDF production 22
2.5 Economic calculation 27
2.6 Comparison to the usage of primary energy sources 28
3. Results 30
3.1 Waste characterization 30
3.2 Mass Balance of RDF Production 33
3.3 Water content 34
3.3.1 Waste from Characterization 34
3.3.2 RDF 35
3.4 Heating value 36
3.4.1 Waste from Characterization 36
3.4.2 RDF 37
3.5 Heavy metals 38
3.5.1 Waste from Characterization 38
3.5.2 RDF 39
3.6 Chloride and Sulfur content 41
3.6.1 Waste from Characterization 41
3.6.2 RDF 42
3.7 Total carbon content 42
3.8 Biogenic / fossil carbon content / Ash 43
3.9 Methane avoidance potential 44
3.10 CO2e emission through RDF usage 45
3.11 Economic comparison 46
3.12 Comparison to coal 47
4. Discussion 48
4.1 1st Thesis 48
4.2 2nd Thesis 53
4.3 3rd Thesis 61
4.3.1 Mechanical requirements 62
4.3.2 Caloric requirements 63
4.3.3 Chemical requirements 64
4.4 4th Thesis 71
4.4.1 Environmental benefit 71
4.4.2 Economical benefit 74
5. Conclusion 77
References 79
Annex I - Tables I
Affidavit â Eidesstattliche ErklĂ€rung
Impact of electrically assisted bicycles on physical activity and traffic accident risk: a prospective observational study
Background Electrically assisted bicycles (e-bikes) have become increasingly popular and may facilitate active commuting and recreational cycling.Objective To evaluate the physical activity levels and usage characteristics of e-bikers and conventional cyclists under real-world conditions.Methods We conducted a prospective observational study in Germany to examine the effects of e-biking compared with conventional cycling on reaching the World Health Organization (WHO) target for physical activityâat least 150 min of moderate-to-vigorous physical activity (MVPA) per week. Study participants (1250 e-bikers and 629 conventional bike users) were equipped with activity trackers to assess the time, distance and heart rate during cycling over four consecutive weeks. Questionnaires were used to assess any traffic accidents incurred over 12 months.Results The proportion of participants reaching 150 min of MVPA per week was higher for conventional bike users than for e-bike users (35.0% vs 22.4%, p<0.001). In a multiple regression model, the odds of reaching the physical activity target were lower for e-biking than for conventional biking (OR=0.56; 95% CI 0.43 to 0.72) with age, sex, comorbidities and bike usage patterns as confounding factors. No significant differences were observed between bike groups for traffic accidents, yet when controlled for cycling time and frequency of cycling e-bikers had a higher risk of a traffic accident (OR=1.63; 95% CI 1.02 to 2.58).Conclusion E-bikes are associated with a lower probability of reaching WHO targets for MVPA due to reduced duration and a reduced cardiovascular effort during riding. However, e-bikes might facilitate active transportation, particularly in older individuals or those with pre-existing conditions
Flexible and Coherent Soft X-ray Pulses at High Repetition Rate: Current Research and Perspectives
The successful realization of high gain free-electron lasers has opened new possibilities to X-ray scientists for investigating matter in different states. The availability of unprecedented photon properties stimulated the development of new experimental techniques capable of taking full advantage of these options and has started a virtuous collaboration between machine experts and photon users to improve further and optimize the generated X-ray pulses. Over the recent years, this has led to the development of several advanced free-electron laser (FEL) schemes to tailor the photon properties to specific experimental demands. Presently, tunable wavelength X-ray pulses with extremely high brilliance and short pulse characteristics are a few of the many options available at FELs. Few facilities can offer options such as narrowband or extremely short pulses below one fs duration and simultaneous pulses of multiple colors enabling resonant X-ray pumpâX-ray probe experiments with sub fs resolution. Fully coherent X-ray radiation (both spatial and temporal) can also be provided. This new option has stimulated the application of coherent control techniques to the X-ray world, allowing for experiments with few attoseconds resolution. FELs often operate at a relatively low repetition rate, typically on the order of tens of Hz. At FLASH and the European XFEL, however, the superconducting accelerators allow generating thousands of pulses per second. With the implementation of a new seeded FEL line and with an upgrade at FLASH linac, all the new features will become available in the soft X-ray spectral range down to the oxygen K edge with unprecedented average photon flux due to the high repetition rate of pulses
Flexible and Coherent Soft X-ray Pulses at High Repetition Rate
The successful realization of high gain free-electron lasers has opened new possibilities to X-ray scientists for investigating matter in different states. The availability of unprecedented photon properties stimulated the development of new experimental techniques capable of taking full advantage of these options and has started a virtuous collaboration between machine experts and photon users to improve further and optimize the generated X-ray pulses. Over the recent years, this has led to the development of several advanced free-electron laser (FEL) schemes to tailor the photon properties to specific experimental needs. Nowadays, tunable wavelength X-ray pulses with extremely high brilliance and short pulse characteristics are a few of the many options available at FELs. Few facilities can offer options such as narrowband or extremely short pulses below one~fs duration and simultaneous pulses of multiple colors enabling resonant X-ray pump - X-ray probe experiments with sub fs resolution. Fully coherent X-ray radiation (both spatial and temporal) can also be provided and has stimulated the application of coherent control techniques to the X-ray world, allowing for experiments with few attoseconds resolution. FELs often operate at a relatively low repetition rate, typically on the order of tens of Hz. At FLASH and the European XFEL, however, the superconducting accelerators allow generating thousands of pulses per second.With the implementation of a new seeded FEL line and with an upgrade at FLASH linac, all the new features will become available in the soft-X-ray spectral range down to the oxygen K edge with unprecedented average photon flux due to the high repetition rate of pulses