Precision laboratory UV and IR wavelengths for cosmological and astrophysical applications

The quality of astronomical spectra is now so high that the accuracy of the laboratory data is getting more and more important for the analysis and interpretation. Both in astrophysics and cosmology the needs for accurate laboratory wavelengths have increased with the development of new ground-based and air-borne telescopes and spectrographs. The high resolution UV Fourier Transform spectrometer at Lund Observatory is being used for studying laboratory spectra of astrophysically important elements. Measurements of accurate laboratory UV and IR wavelengths have been made for cosmological and astrophysical applications.Comment: To appear in the proceedings of "Precision Spectroscopy in Astrophysics", Aveiro, Portugal, Sep. 2006, eds Pasquini et al., ESO Astrophysics Symposia. 2 pages, 2 figure

Steering green buses : The opportunities and challenges of introducing renewable fuel in public transport

The aim of this thesis is to compare and analyse the introduction of renewable fuel in the public transport sector, focusing on the challenges and opportunities encountered by involved stakeholders on the regional and local levels. The results contribute to answering three research questions: 1) How do organisational factors and local and regional contextual factors influence the introduction of renewable fuel? 2) What are the challenges and opportunities of using green public procurement as a policy tool to introduce renewable fuel in the public transport sector? 3) How do the challenges and opportunities regarding the introduction of renewable fuel differ depending on the type of renewable fuel? Four papers are included in the thesis. Paper I compares and analyses how factors identified in green public procurement research (strategies, requirements, cost, size and knowledge) influence the choices made when introducing renewable fuel in two Swedish regions. The findings show that the influence of the factors is highly case-specific and that differences in their strategic approach caused regions to express requirements for fuel differently in tender documents. Functional requirements were used by the public authorities to increase the share of renewable fuel in a cost efficient way and at the same time allow room for flexibility and leave more control to the operators. Specific requirements were strategically used to create local markets for biogas, which poses higher demands on political backing, knowledge by the public authorities, and an acceptance of increased costs. These findings were further elaborated in paper II, where introduction of renewable fuel in ten more Swedish regions was studied. The results confirmed to a large extent the challenges and opportunities from paper I. Further, regions that had introduced another renewable fuel than biodiesel had either used specific requirements or introduced the fuel in publicly operated bus services. The scope of paper III complements the findings by looking more in detail at how environmental requirements have been expressed, by performing a content analysis of Swedish tender documents. The results show that size of the procurement and type of traffic influence how environmental requirements are set. Further, both ambitious functional requirements and specific requirements for fuel are more common in large tenders in city traffic – this confirms and exemplifies the importance of context when renewable fuel is introduced through public procurement. In paper IV, the focus is solely on the introduction of electric buses by comparing experiences in Sweden and England. It was concluded that most challenges are case-specific on the city level, for example, passenger demand and bus route characteristics, but also financial and regulatory support from the national government can have an influence. Additionally, the relationship and division of roles between involved stakeholders are central to overcome challenges in all cities. Overall, this thesis concludes that green public procurement can be successful for introducing renwable fuel. By expressing requirements differently in the tender documents, public authorities have been able to influence the introduction to a varying degree which has led to different challenges and opportunities for the involved stakeholders as well as different outcomes for renewable fuel. Nevertheless, introduction of emerging technologies (eg. electric buses) was shown to be a challenge when public transport was procured. Alternative introduction strategies were seen for electric buses, such as test projects, introduction under current procurement contracts, increased collaboration between stakeholders and more responsibility to cover for uncertainties taken by the public authorities. In summary, the challenges and opportunities of introducing renewable fuel are highly case-specific and strongly associated with the specific fuel in question

Accurate laboratory ultraviolet wavelengths for quasar absorption-line constraints on varying fundamental constants

The most precise method of investigating possible space-time variations of the fine-structure constant, using high-redshift quasar absorption lines, is the many-multiplet (MM) method. For reliable results this method requires very accurate relative laboratory wavelengths for a number of UV resonance transitions from several different ionic species. For this purpose laboratory wavelengths and wavenumbers of 23 UV lines from MgI, MgII, TiII, CrII, MnII, FeII and ZnII have been measured using high-resolution Fourier Transform (FT) spectrometry. The spectra of the different ions (except for one FeII line, one MgI line and the TiII lines) are all measured simultaneously in the same FT spectrometry recording by using a composite hollow cathode as a light source. This decreases the relative uncertainties of all the wavelengths. In addition to any measurement uncertainty, the wavelength uncertainty is determined by that of the ArII calibration lines, by possible pressure shifts and by illumination effects. The absolute wavenumbers have uncertainties of typically 0.001 to 0.002 cm^(-1) (0.06 to 0.1 mAA at 2500 AA), while the relative wavenumbers for strong, symmetric lines in the same spectral recording have uncertainties of 0.0005 cm^(-1) (0.03 mAA at 2500 AA) or better, depending mostly on uncertainties in the line fitting procedure. This high relative precision greatly reduces the potential for systematic effects in the MM method, while the new TiII measurements now allow these transitions to be used in MM analyses.Comment: Accepted for publication in MNRAS, 10 pages, 9 figure

Introducing renewable fuels in public bus transport – challenges and opportunities

Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Energy auditing and enhanced implementation of energy efficiency strategies and actions through networks for SMEs – learning across borders in Sweden, Germany and Switzerland

Rapporten innefattar en detaljerad beskrivning och utvärdering av de existerande tyska och schweiziska nätverk för energieffektivisering. Baserat på resultatet, finns även ett förslag på en modell för energieffektiviseringsnätverk anpassad för Sverige som består av fyra faser: rekryteringsfas, energikartläggningsfas, nätverksfas och uppföljningsfas. Från studien drogs även slutsatsen att de viktigaste delarna i ett väl fungerande nätverk är: en väl planerad rekryteringsstrategi, tydlig målsättning, regelbundna nätverksmöten samt årlig uppföljning av företagens arbete och framsteg

Energy auditing and enhanced implementation of energy efficiency strategies and actions through networks for SMEs – learning across borders in Sweden, Germany and Switzerland

Rapporten är en kartläggning av Tyska och Schweiziska nätverk för energieffektivisering och bygger på litteraturstudier och intervjuer. Utifrån vad som kommer fram i kartläggningen ges ett förslag på hur en svensk modell för energieffektiviseringsnätverk bör se ut

Introducing renewable fuel in public bus transport – challenges and opportunities

The differences between type and share of renewable fuel in Swedish public bus transport is large today. A previous study showed that the differences between regions could possibly be related to regional context and choice of strategic approach. Therefore, the aim of this study is to further analyse the strategic approach for implementation of renewable fuel in ten Swedish transport regions, looking at how actors in the regions experience the challenges and opportunities with use of green public procurement as a tool to implement renewable fuels in relation to economical, geographical, organisational and political factors. The findings from this study confirms that functional requirements is the most cost efficient way to introduce renewable fuels, but at the same time it always results in the cheapest fuel, which today is biodiesel. If a region instead wants to create a market for production, use or infrastructure for a fuel such as biogas, they either have to use specific requirements or own the traffic themselves.Institute of Transport and Logistics Studies. Faculty of Economics and Business. The University of Sydne

Accurate Ritz wavelengths of parity-forbidden [Fe II], [Ti II] and [Cr II] infrared lines of astrophysical interest

With new astronomical infrared spectrographs the demands of accurate atomic data in the infrared have increased. In this region there is a large amount of parity-forbidden lines, which are of importance in diagnostics of low-density astrophysical plasmas. We present improved, experimentally determined, energy levels for the lowest even LS terms of Fe II, Ti II and Cr II, along with accurate Ritz wavelengths for parity-forbidden transitions between and within these terms. Spectra of Fe II, Ti II and Cr II have been produced in a hollow cathode discharge lamp and acquired using high-resolution Fourier Transform (FT) spectrometry. The energy levels have been determined by using observed allowed ultraviolet transitions connecting the even terms with upper odd terms. Ritz wavelengths of parity-forbidden lines have then been determined. Energy levels of the four lowest Fe II terms (a$^{6}$D, a$^{4}$F, a$^{4}$D and a$^{4}$P) have been determined, resulting in 97 different parity-forbidden transitions with wavelengths between 0.74 and 87 micron. For Ti II the energy levels of the two lowest terms (a$^{4}$F and b$^{4}$F) have been determined, resulting in 24 different parity-forbidden transitions with wavelengths between 8.9 and 130 micron. Also for Cr II the energy levels of the two lowest terms (a$^{6}$S and a$^{6}$D) have been determined, in this case resulting in 12 different parity-forbidden transitions with wavelengths between 0.80 and 140 micron.Comment: Accepted for publication in A&A, 13 pages, 6 figures, 9 table

Frequency Metrology on single trapped ions in the weak binding limit: The 3s1/2-3p3/2 transition in 24-Mg+

We demonstrate a method for precision spectroscopy on trapped ions in the limit of unresolved motional sidebands. By sympathetic cooling of a chain of crystallized ions we suppress adverse temperature variations induced by the spectroscopy laser that usually lead to a distorted line profle and obtain a Voigt profile with negligible distortions. We applied the method to measure the absolute frequency of the astrophysically relevant D2 transition in single 24-Mg+ ions and find 1072082934.33(16)MHz, a nearly 400fold improvement over previous results. Further, we find the excited state lifetime to be 3.84(10) ns.Comment: 4 pages, 5 figure

Experimental Ca I oscillator strengths for the 4p-5s triplet

Context. Transition lines of neutral calcium are observed in the spectra of stellar and substellar objects. In particular, the abundance of α-elements in metal-poor stars can place important constraints on the galactic chemical evolution. Such stellar abundance analyses rely heavily on accurate values for the oscillator strength of the observable transitions. Theoretical oscillator strengths are available for most neutral calcium lines visible in stellar spectra, but there are a limited number of experimental values in the literature. Aims. We present new and improved experimental oscillator strengths for the optical Ca