| 1. |
- Andersson, Håkan A., 1948-
(författare)
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Svenska småföretags användning av reserveringar för resultatutjämning och intern finansiering
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Small firms often have inadequate access to the capital necessary for sucessful management. The Swedish Government introduced in the mid-1990s allowance rules that facilitate retention of profit for sole proprietorships and partnership firms. The tax credits arising from the allowances give certain benefits as a source of financing compared to traditional forms of credits. Among the more essential benefits are that the payment for some parts of the tax credit can be put on hold almost indefinitely, or alternatively never be paid. The firms are free to use these means, and the responsibility of future payment of the postponed tax debt stays with the individual firms. The comprehensive purpose of the dissertation may be stated as to increase the understanding of small Swedish firms, especially sole proprietorships, utilizing possibilities for allowances for income smoothing and internal financing. At the beginning the dissertation describes case studies, comprising a smaller selection of microfirms. With a starting-point from the accounted and reported income-tax returns, alternative calculations are made where additional positive tax and finance effects appear possible to obtain. One purpose of these studies is to increase the insight regarding the possibilities of income smoothing and internal financing that arise from utilizing these allowances. These studies also illuminate, to what extent and in what way they are being used in reality. Another objective of these studies is to give a more substantive insight into the technics behind the different allowances, appropriation to positive or negative interest rate allocation appropriation or dissolving of tax allocation reserve appropriation or dissolving of “expansion fund” Theories regarding the creation of resources, through building of capital, and theories on financial planning and strategy are studied. The purpose is to find support for the choice of theoretical grounded underlying independent variables that can be used in cross-sectional studies to explain the use of the possibilities of appropriations. Theories of finance that are of greatest interest, in the operationalisation of these variables, are theories that discuss the choices of different financing alternatives for small firms. The “pecking order theory”, describes the firm’s order of priority when choices of finance alternatives are made. The concept of “financial bootstrapping” expands the frame for different forms of financing choices that especially very small firms have at their disposal.The last part of the theoretical frame deals with the phenomenon of “income smoothing,” which can be translated as leveling out profits/losses. A number of financial and non-financial variables are supported by and operationalised from these financial theories e.g., return on sales, capital turnover, quick ratio and debt-to-equity ratio, respectively age, gender and line of business. Cross-sectional studies are implemented for the taxation years of 1996 and 1999, on databases that have been extracted from Statistics Sweden. The group of 87,276 sole proprietorships included in the study were required to complete tax returns and pay taxes for the business activity according to the supporting schedule, N2, information from the sole proprietorships’ income statement and balance sheet in an accounting statement that comes with the income tax return form. The possibilities of allowances are considered as dependent variables. The intention of the cross-sectional studies is to survey and describe the utilization of possible allowances, with the support of the financial and non-financial independent variables. The connection of these variables to the decision of sole proprietorships to appropriate to the tax allocation reserve is also summarized in a logistic regression model. A number of theoretically based propositions are made for the purpose of observing how the variables are connected to the chances that sole proprietorships actually appropriate to this form of allowance. Appropriation to the tax allocation reserve stands out as the most practiced form of allowance. The studies also clarify that utilization varies among different forms of allowances, but that not all firms that have the prerequisites to utilize the possibilities really do so to the full. A further utilization of the different possibilities of allowances is often conceivable. For the sole proprietorships that are not utilizing these possibilities, the allowances should be considered eligible as a contribution to internal financing and to increase access to capital.
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| 2. |
- Börjesson Axén, Jenny, 1986-, et al.
(författare)
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A Structural Investigation into the OCV Hysteresis of the Ni(OH)2 Electrode
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Powder X-ray diffraction (XRPD), X-ray absorption spectroscopy (EXAFS and XANES) and Raman spectroscopy were used to study chemical changes in the polycrystalline nickel hydroxide positive electrode material of a NiMH battery at four states of charge: 0%, 50% and 100% charged, and 50% discharged. The two 50% samples were at the same state of charge but in different hysteresis states, manifested by differences in the open circuit potential. The nickel hydroxide electrodes consist of particles in the µm size range, and all measurements were performed ex situ. The material studied was taken from commercial batteries and as such contained both metallic nickel particles, cobalt, and zinc dopants in the active Ni(OH)2 material as well as a cobalt oxide surface layer. Combining the results from all the characterization methods was necessary to better understand the chemistry behind the physio-chemical hysteresis behavior in this complex system. Our results show that there are structural differences between the two 50% samples. Comparison of the XRPD results and the EXAFS results on the nickel edge indicate a presence of the kinetically favored TP2-NiOOH phase in the transition between β-Ni(OH)2 and β-NiOOH and that the amount differs between the two hysteresis states. The measurements on the zinc edge using EXAFS and XANES suggest short range differences in the active material bulk that stems from disorder. Raman spectroscopy measurements show a difference in degree of lithium intercalation in the LiCoO2 surface layer between the hysteresis states. As electrochemistry takes place on the surface of the particles, it is likely that differences in the surface structure are responsible for the open circuit voltage hysteresis. However, due to the coherence of the structure differences detected, it is probable that they are all connected and have a part in the observed behavior.
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| 3. |
- Ciosek Högström, Katarzyna, 1984-, et al.
(författare)
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Impact of the flame retardant additive triphenyl phosphate (TPP) on the performance of graphite/LiFePO4 cells in high power applications
- 2014
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Ingår i: Journal of Power Sources. - : Elsevier BV. - 0378-7753 .- 1873-2755. ; 256, s. 430-439
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Tidskriftsartikel (refereegranskat)abstract
- This study presents an extensive characterization of a standard Li-ion battery (LiB) electrolyte containing different concentrations of the flame retardant triphenyl phosphate (TPP) in the context of high power applications. Electrolyte characterization shows only a minor decrease in the electrolyte flammability for low TPP concentrations. The addition of TPP to the electrolyte leads to increased viscosity and decreased conductivity. The solvation of the lithium ion charge carriers seem to be directly affected by the TPP addition as evidenced by Raman spectroscopy and increased mass-transport resistivity. Graphite/LiFePO4 full cell tests show the energy efficiency to decrease with the addition of TPP. Specifically, diffusion resistivity is observed to be the main source of increased losses. Furthermore, TPP influences the interface chemistry on both the positive and the negative electrode. Higher concentrations of TPP lead to thicker interface layers on LiFePO4. Even though TPP is not electrochemically reduced on graphite, it does participate in SEI formation. TPP cannot be considered a suitable flame retardant for high power applications as there is only a minor impact of TPP on the flammability of the electrolyte for low concentrations of TPP, and a significant increase in polarization is observed for higher concentrations of TPP. (C) 2014 Elsevier B.V. All rights reserved.
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| 4. |
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| 5. |
- Fang, Yuan, et al.
(författare)
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Lithium insertion in hard carbon as observed by 7Li NMR and XRD. The local and mesoscopic order and their relevance for lithium storage and diffusion
- 2022
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry. - 2050-7488 .- 2050-7496. ; 10:18, s. 10069-10082
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Tidskriftsartikel (refereegranskat)abstract
- We investigate hard carbon fibers in different states of charge by a combination of 7Li-NMR and 2D-XRD. In particular, we record the quadrupole-split 7Li-NMR spectra and 7Li longitudinal relaxation over a wide temperature range, and determine lithium self-diffusion both parallel and perpendicular to the fiber axis. Recording the temperature dependence permits us to interpret the presence of motional averaging of spin couplings for mobile Li. The joint analysis shows that at low Li content, Li occupies sites that lack ordered coordination and delocalized electrons and are collected in disordered spatial domains. Upon increasing the Li content, ordered sites collected in ordered domains become populated. Both disordered and ordered domains have a high inherent heterogeneity with a typical spatial extension of a few nanometers. The disordered domains exhibit a continuous topology that permits unhindered diffusion within it. At high Li content we also observe the presence of very small (∼nm) particles of metallic lithium. The joint analysis of XRD in combination with diffusion anisotropy, and anisotropy from the 7Li-NMR spectrum (with samples oriented differently with regard to the applied magnetic field), shows that the mesoscopic structure is made by ordered domains arranged in a cylindrically rolled-up manner with the mesoscopic axis parallel to the fiber axis.
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| 6. |
- Häggblad, Erik, et al.
(författare)
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Myocardial tissue oxygenation estimated with calibrated diffuse reflectance spectroscopy during coronary artery bypass grafting
- 2008
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Ingår i: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668 .- 1560-2281. ; 13:5, s. 054030-
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Tidskriftsartikel (refereegranskat)abstract
- We present a study using a method able to assess tissue oxygenation, taking into account the absorption and the level of scattering in myocardial tissue using a calibrated fiber optic probe. With this method, interindividual comparisons of oxygenation can be made despite varying tissue optical properties during coronary artery bypass grafting (CABG). During CABG, there are needs for methods allowing continuous monitoring and prediction of the metabolism in the myocardial tissue. 14 patients undergoing CABG are investigated for tissue oxygenation during different surgical phases using a handheld fiber optic spectroscopic probe with a source-detector distance of less than 1 mm. The probe is calibrated using a light transport model, relating the absorption and reduced scattering coefficients (mu(a) and mu()(s)) to the measured spectra. By solving the inverse problem, absolute measures of tissue oxygenation are evaluated by the sum of oxygenized hemoglobin and myoglobin. Agreement between the model and measurements is obtained with an average correlation coefficient R-2 of 0.96. Oxygenation is found to be significantly elevated after aorta cross-clamping and cardioplegic infusion, as well as after reperfusion, compared to a baseline (p < 0.05). Tissue oxygenation decreases during cardiac arrest and increases after reperfusion.
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| 7. |
- Ihonen, J., et al.
(författare)
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A novel polymer electrolyte fuel cell for laboratory investigations and in-situ contact resistance measurements
- 2001
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Ingår i: Electrochimica Acta. - 0013-4686 .- 1873-3859. ; 46:19, s. 2899-2911
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Tidskriftsartikel (refereegranskat)abstract
- A novel polymer electrolyte membrane fuel cell and assembly was developed for laboratory investigations. In this cell a simultaneous measurement of clamping pressure and contact resistances is possible. In the study presented this paper, the cell was utilised in in-situ contact resistance measurements of unplated and plated stainless steel (type 316). These contact resistances were studied in situ as a function of time, clamping pressure, gas pressure and current density. Ex-situ measurements were used to validate the in-situ contact resistance measurements. The validity and error sources of the applied in-situ measurement method were studied using both computer simulations and experiments.
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| 8. |
- Ihonen, J., et al.
(författare)
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Investigation of mass-transport limitations in the solid polymer fuel cell cathode - II. Experimental
- 2002
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 149:4, s. A448-A454
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we investigated the kinetics and mass-transport limitations of the oxygen reduction reaction in the solid polymer fuel cell. The information obtained from electrochemical experiments and electrode characterization was analyzed with an agglomerate model presented in Part I of this paper. The electrochemical behavior of the cathode was studied by polarizing vs. a hydrogen reference electrode at a low sweep rate. For each potential, the iR-drop was measured with the current-interrupt technique. The cathode structure was investigated by porosimetry and electron microscopy techniques. The effects on the cathode polarization curves of the active layer thickness, oxygen partial pressure, and humidity of the oxygen gas were investigated. On the basis of the model results, conclusions could be drawn regarding the nature of mass-transport limitations because of the characteristic shape of the experimental polarization curves. The simulated curves were fitted to the experimental ones to give the kinetic and masstransport parameters. Finally, we discuss the validity of the model with regard to the values obtained for the transport and structural parameters.
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| 9. |
- Jaouen, F., et al.
(författare)
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Investigation of mass-transport limitations in the solid polymer fuel cell cathode - I. Mathematical model
- 2002
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Ingår i: Journal of the Electrochemical Society. - : The Electrochemical Society. - 0013-4651 .- 1945-7111. ; 149:4, s. A437-A447
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a one-dimensional, steady-state agglomerate model was used to describe the functioning and the mass transport limitations of the cathode in the solid polymer fuel cell (SPFC). This mathematical model is then compared to experimental results obtained on cathodes in an SPFC. The following processes were considered: Tafel kinetics of the oxygen reduction reaction, proton migration, oxygen diffusion in the agglomerates, and diffusion of a ternary gas mixture O-2/N-2/water vapor in the pores of the active layer and of the gas backing. The model shows that limitation by proton migration in the active layer or by oxygen diffusion in the agglomerates leads to a doubling of the Tafel slope at higher current densities. For those two types of transport limitations, the dependence of the reaction rate on the active-layer thickness, oxygen partial pressure, and relative humidity of the gas were simulated. When additional limitation due to slow gas phase diffusion appears, the double Tafel slope is distorted. A mathematical expression for the limiting current density due to this process is presented. By using this expression, it is possible to correct the polarization curves for slow gas phase diffusion.
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| 10. |
- Leijonmarck, Simon, et al.
(författare)
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Direct electropolymerization of polymer electrolytes onto carbon fibers - A route to structural batteries?
- 2014
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Ingår i: 16th European Conference on Composite Materials, ECCM 2014. - : European Conference on Composite Materials, ECCM. - 9780000000002
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Konferensbidrag (refereegranskat)abstract
- In an effort to further reduce weight of carbon fibre reinforced composites, the concept of structural batteries has arisen. A structural battery is a multifunctional material managing both energy storage and enabling of structural integrity. More specific, the carbon fibres in the composites are used as negative electrode in a Li-ion battery. A crucial part of such a battery is the preparation of a thin, ionically conductive and stiff polymer matrix. One route to realize this is the use of electropolymerization, which can cover each individual fibre with polymer. In this study, the surface morphology of coated carbon fibres is investigated with electron microscopy and atomic force microscopy. Additionally, the curing degree as a function of process temperature during polymerization is tested.
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| 11. |
- Lindbergh, Lars, 1964-
(författare)
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Essays of Financial Performance and Capital Structure
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of an introductory chapter and four self-contained essays on financial performance and capital structure. Essay I assesses the strength of strategic inputs into profitability among firms within several sub-sectors within the industrial service sector in the U.S. and Sweden. In this study we employ an ordinary least square regression. The results, coupled with structural observations on production sectors, suggest that significant differences may indeed occur in both productivity and pricing in the two systems, i.e. the U.S. and Sweden. Essay II estimates the impact of operating costs and cost of debt on revenue, profit generation and asset retention in public housing companies in Sweden. A general conclusion to draw from the empirical results is that expentitures on consolidated maintenance is not only associated with short-term rental revenues, but undoubtedly long-term viability as well. Further, first difference results suggested that negotiated rents produced operating profits that kept pace with revenues over the time period of study. Essay III examines the impact of selected financial and contextual variables on managers’ decisions to appropriate funds to tax allowances in small firms in Sweden. The motive for appropriating to the tax allocation reserve is twofold. First, the tax allocation reserve is intended to lower the tax levy on investments financed with internally generated income. Second, it creates a possibility for firms to smooth income over a number of years. The results, from the logistic regression, suggest that financial performance, financial position and prior appropriations do impact on managers’ decision to appropriate. Essay IV examines the association between the two sides of the balance sheet based on financial statement information from small firms in Sweden The results of the multivariate canonical correlation analysis provides some support to the hypotheses that firms develop patterns, in their use of assets and their financing.
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| 12. |
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| 13. |
- Willgert, Markus, et al.
(författare)
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Cellulose nanofibril reinforced composite electrolytes for lithium ion battery applications
- 2014
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 2:33, s. 13556-13564
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Tidskriftsartikel (refereegranskat)abstract
- The present study describes the synthesis and characterization of a series of four composite electrolytes for lithium ion battery applications. The two-phase electrolytes are composed of a soft, ionic conductive poly(ethylene glycol) (PEG) matrix having stiff nanofibrillated cellulose (CNF) paper as reinforcement to provide mechanical integrity. The reinforcing CNF is modified in order to create covalent bonds between the phases which is particularly beneficial when swelling the composite with a liquid electrolyte to enhance the ionic conductivity. After swelling the composite polymer electrolyte, forming a gelled structure, values of ionic conductivity at 5 x 10(-5) S cm(-1) and an elastic modulus around 400 MPa at 25 degrees C are obtained.
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| 14. |
- Öberg, Henrik
(författare)
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Electronic structure and spectroscopy calculations in fuel cell catalysis
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents joint experimental and theoretical studies of surface phenomena at an electronic structure level in proton exchange membrane fuel cells (PEM-FC's). The fuel cell activity can be related to the oxygen reduction taking place at the cathodic surface through the oxygen reduction reaction (ORR). Under certain conditions the dissociative adsorption of O2 becomes the rate limiting reaction step and may therefore affect the overall fuel cell activity. Using core-level spectroscopy in terms of X-ray Photoemission Spectroscopy (XPS), the O2 dissociation barrier on Pt(111) has been determined and density functional theory (DFT) calculations reproduce the estimate well, using structure models that account for lateral adsorbate-adsorbate interactions, a finding that may have implications on the approach to calculate electronic structure properties of heterogeneous surface catalysis. Through a Brønsted-Evans-Polanyi (BEP) relation, the activation barrier for dissociation can be connected to the chemisorption energy of the atomic oxygen binding to the Pt surface. By affecting this energy, the activity of the fuel cell can be tuned; straining the Pt lattice weakens the O-Pt bond according to the Nørskov-Hammer d-band model which relates the adsorbate-substrate chemisorption energy to the position of the d-band center relative the Fermi level. X-ray Absorption (XAS) and Emission Spectroscopy (XES) have been used together with DFT to investigate the electronic structure effect in Pt due to strain, by depositing overlayers of Pt on Cu(111). The d-band model can to some extent be employed to describe the strain effect - but the discrepancies between the calculations and the experiments remain an open question at present. Furthermore, the oxidation of the Pt(111) surface have been studied using XPS and XAS. DFT calculations support the experimental picture and suggest an oxidation resulting in an α-PtO2 type of surface-oxide.
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