Endre søk
Link to record
Permanent link

Direct link
BETA
Paul, Jan
Publikasjoner (10 av 96) Visa alla publikasjoner
Smith, M. L., Sekarana, B., Öztas, A. M. & Paul, J. (2010). Constraints on dark energy and dark matter from supernovae and gamma ray burst data. In: Karl Lefebvre; Raoul Garcia (Ed.), Dark Energy: Theories, Developments and Implications. Paper presented at . Hauppauge, NY: Nova Science Publishers, Incorporated
Åpne denne publikasjonen i ny fane eller vindu >>Constraints on dark energy and dark matter from supernovae and gamma ray burst data
2010 (engelsk)Inngår i: Dark Energy: Theories, Developments and Implications, Hauppauge, NY: Nova Science Publishers, Incorporated , 2010Kapittel i bok, del av antologi (Annet vitenskapelig)
sted, utgiver, år, opplag, sider
Hauppauge, NY: Nova Science Publishers, Incorporated, 2010
Serie
Space Science, Exploration and Policies
Emneord
Technology - Engineering physics, Teknikvetenskap - Teknisk fysik
HSV kategori
Forskningsprogram
Fysik
Identifikatorer
urn:nbn:se:ltu:diva-20320 (URN)3e9b09f0-a105-11de-8293-000ea68e967b (Lokal ID)978-1-61668-271-2 (ISBN)3e9b09f0-a105-11de-8293-000ea68e967b (Arkivnummer)3e9b09f0-a105-11de-8293-000ea68e967b (OAI)
Merknad

Godkänd; 2010; 20090914 (ysko)

Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-03-09bibliografisk kontrollert
Hoffmann, F. M., Yang, Y., Paul, J., White, M. G. & Hrbek, J. (2010). Hydrogenation of carbon dioxide by water: alkali-promoted synthesis of formate (ed.). Journal of Physical Chemistry Letters, 1(14), 2130-2134
Åpne denne publikasjonen i ny fane eller vindu >>Hydrogenation of carbon dioxide by water: alkali-promoted synthesis of formate
Vise andre…
2010 (engelsk)Inngår i: Journal of Physical Chemistry Letters, Vol. 1, nr 14, s. 2130-2134Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Conversion of carbon,dioxide utilizing protons from water decomposition is likely to provide a sustainable source of fuels and chemicals in the future. We present here a time-evolved infrared reflection absorption spectroscopy (IRAS) and temperature-programmed desorption (TPD) study of the reaction of CO2 + H2O in thin potassium layers. Reaction at temperatures below 200 K results in the hydrogenation of carbon dioxide to potassium formate. Thermal stability of the formate, together with its sequential transformation to oxalate and to carbonate, is monitored and discussed. The data of this model study suggest a dual promoter mechanism of the potassium: the activation of CO2 and the dissociation of water. Reaction at temperatures above 200 K, in contrast, is characterized by the absence of formate and the direct reaction of CO2 to oxalate, due to a drastic reduction of the sticking coefficient of water at higher temperatures

HSV kategori
Forskningsprogram
Fysik
Identifikatorer
urn:nbn:se:ltu:diva-9470 (URN)10.1021/jz1007356 (DOI)000280021000015 ()2-s2.0-79959512159 (Scopus ID)81bc2880-a128-11df-a707-000ea68e967b (Lokal ID)81bc2880-a128-11df-a707-000ea68e967b (Arkivnummer)81bc2880-a128-11df-a707-000ea68e967b (OAI)
Merknad

Validerad; 2010; 20100806 (andbra)

Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Öztas, A. M., Smith, M. L. & Paul, J. (2008). Spacetime curvature is important for cosmology constrained with supernova emissions (ed.). International journal of theoretical physics, 47(9), 2464-2478
Åpne denne publikasjonen i ny fane eller vindu >>Spacetime curvature is important for cosmology constrained with supernova emissions
2008 (engelsk)Inngår i: International journal of theoretical physics, ISSN 0020-7748, E-ISSN 1572-9575, Vol. 47, nr 9, s. 2464-2478Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

We investigate universe expansion models as functions of emission frequency ratio decline rather than redshift z, using the latest on-line, self-consistent data from 192 supernovae. We present results for simpler and some current models of cosmology, including those with dark energy (standard model) and a recent model correcting for the effect of a small time-dependent, emission frequency increase with lookback. This new model, with a gentle lookback decline of the Planck constant, and the standard model fit the data with similar confidence according to Bayesian Information Criteria. The standard model tends towards solutions high in matter density while remaining flat, but models without dark energy tend towards dilute universes with significant spacetime and curvature and a smaller Hubble constant. We conclude the normalized spacetime parameter, Ω k , should not be ignored and it includes the combined contributions of huge spacetime magnitude and curvature.

HSV kategori
Forskningsprogram
Fysik
Identifikatorer
urn:nbn:se:ltu:diva-15434 (URN)10.1007/s10773-008-9680-7 (DOI)000258277800029 ()2-s2.0-49349107778 (Scopus ID)ef0a3260-3951-11dd-8721-000ea68e967b (Lokal ID)ef0a3260-3951-11dd-8721-000ea68e967b (Arkivnummer)ef0a3260-3951-11dd-8721-000ea68e967b (OAI)
Merknad

Validerad; 2008; 20080613 (ysko)

Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Mehtap, P., Sandström, Å. & Paul, J. (2007). Bioleaching of sulphidic concentrates ans pH-control with ashes (ed.). In: (Ed.), (Ed.), World of coal ash: 2007 proceedings ; science, applications and sustainability ; Covington, Kentucky, May 7 - 10, 2007 ; 2007 World of Coal Ash (WOCA) Conference. Paper presented at World of coal ash conference : 07/05/2007 - 10/05/2007. Lexington, Ky
Åpne denne publikasjonen i ny fane eller vindu >>Bioleaching of sulphidic concentrates ans pH-control with ashes
2007 (engelsk)Inngår i: World of coal ash: 2007 proceedings ; science, applications and sustainability ; Covington, Kentucky, May 7 - 10, 2007 ; 2007 World of Coal Ash (WOCA) Conference, Lexington, Ky, 2007Konferansepaper, Publicerat paper (Fagfellevurdert)
sted, utgiver, år, opplag, sider
Lexington, Ky: , 2007
HSV kategori
Forskningsprogram
Processmetallurgi; Fysik
Identifikatorer
urn:nbn:se:ltu:diva-37319 (URN)b4daa000-aa29-11dc-9057-000ea68e967b (Lokal ID)0-9674971-7-5 (ISBN)b4daa000-aa29-11dc-9057-000ea68e967b (Arkivnummer)b4daa000-aa29-11dc-9057-000ea68e967b (OAI)
Konferanse
World of coal ash conference : 07/05/2007 - 10/05/2007
Merknad
Godkänd; 2007; Bibliografisk uppgift: CD-ROM; 20071214 (cira)Tilgjengelig fra: 2016-10-03 Laget: 2016-10-03 Sist oppdatert: 2017-11-25bibliografisk kontrollert
Smith, M., Öztaş, A. & Paul, J. (2007). Estimation of redshifts from early galaxies (ed.). Annales de la Fondation Louis de Broglie, 32(1), 61-67
Åpne denne publikasjonen i ny fane eller vindu >>Estimation of redshifts from early galaxies
2007 (engelsk)Inngår i: Annales de la Fondation Louis de Broglie, ISSN 0182-4295, E-ISSN 2108-6397, Vol. 32, nr 1, s. 61-67Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Dating early galaxies is a current technical, empirical and theoretical problem. Progress has been made recently calculating these dates using the observed redshift, z, alone. While this relaxes the need for simultaneous determination of luminosity distances with redshifts; accurate redshift determination beyond z ≥ 3 is difficult. We have shown that light emissions tend toward blue with increasing emission age and this is supported by recent data. Here we combine calculations of cosmological times from redshifts alone with the emission frequency model for lookback times. This allows a better gauge between recombination and the first galaxies and may provide additional 50-200 M years between these events.

HSV kategori
Forskningsprogram
Fysik
Identifikatorer
urn:nbn:se:ltu:diva-6639 (URN)4e297300-c26c-11df-a707-000ea68e967b (Lokal ID)4e297300-c26c-11df-a707-000ea68e967b (Arkivnummer)4e297300-c26c-11df-a707-000ea68e967b (OAI)
Merknad

Validerad; 2007; 20100917 (andbra)

Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-03-09bibliografisk kontrollert
Smith, M. L., Oztas, A. M. & Paul, J. (2006). A model of light from ancient blue emissions (ed.). Paper presented at . International journal of theoretical physics, 45(5), 908-923
Åpne denne publikasjonen i ny fane eller vindu >>A model of light from ancient blue emissions
2006 (engelsk)Inngår i: International journal of theoretical physics, ISSN 0020-7748, E-ISSN 1572-9575, Vol. 45, nr 5, s. 908-923Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

A model is presented to explain the luminar distances and associated red-shifts from ancient supernovae. Light frequencies of supernovae type Ia (SNe Ia) vary smoothly with time, decreasing from singularity to present and intergalactic luminar distances are described as linear combinations of Hubble expansion and smaller components from the time-dependent decrease of emission frequencies. When tested with current cosmic matter densities, SNe Ia distances, red-shifts and the Hubble constant the errors between this model and the vacuum energy model favor this new model, though our model suffers from mathematics about zero. An expression between energy and frequency, derived from the model, reducing to the Planck equation for short observation intervals is also discovered and estimated to within 10% using current SNe Ia data. We also propose a relationship for the deceleration of frequency over time, solve at infinity and discover frequency and time will eventually become uncoupled.

HSV kategori
Forskningsprogram
Fysik
Identifikatorer
urn:nbn:se:ltu:diva-3245 (URN)10.1007/s10773-006-9083-6 (DOI)000238832600007 ()2-s2.0-33745746659 (Scopus ID)10cc0d10-f1be-11db-bb1b-000ea68e967b (Lokal ID)10cc0d10-f1be-11db-bb1b-000ea68e967b (Arkivnummer)10cc0d10-f1be-11db-bb1b-000ea68e967b (OAI)
Merknad
Validerad; 2006; 20070423 (ysko)Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Paul, M., Seferinoğlu, M., Ayçık, G. A., Sandström, Å., Smith, M. L. & Paul, J. (2006). Acid leaching of ash and coal: time dependence and trace element occurrences (ed.). Paper presented at . International Journal of Mineral Processing, 79(1), 27-41
Åpne denne publikasjonen i ny fane eller vindu >>Acid leaching of ash and coal: time dependence and trace element occurrences
Vise andre…
2006 (engelsk)Inngår i: International Journal of Mineral Processing, ISSN 0301-7516, E-ISSN 1879-3525, Vol. 79, nr 1, s. 27-41Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The leaching of coal and coal/asphaltite/wood-ashes in sulfuric acid (pH 1.0, 25 °C, S/L, 1:10) was studied as a function of time; acid consumption and extracted metal concentrations are presented. Whole coals consumed acid rapidly during the first few minutes, followed by slow acid consumption. Wood-, lignite-, and asphaltite-ashes consumed acid in two stages, the rapid phase extending < 30 min and the slow phase extended up to 10 days. The rapid phase was dominated by the dissolution of Ca, K and Mg ions for wood-ash, by Ca, Al and Mg ions for lignite-ash and Ca and Mg ions for asphaltite-ash. The sulfur concentration in solution and the concentrations of Ca, Fe, K, Mg, Na, P, Al and Mn in the aqueous phase verified the neutralizing capacity of the untreated ashes as well as the formation of insoluble sulfates in the residues. The slow phase kinetics differed for different fuels and exhibited leaching of several abundant elements-Fe, Al, K, Na and Mn. Trace elements (Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Th, U, V, Zn) sometimes required up to 32 h for maximal extraction from ashes. Suggestions are presented regarding the chemical nature of trace elements in the untreated coals and ashes and suitable residence times for economical industrial processes. We think it possible to combine bacteriological oxidation of sulfidic concentrates of acid leaching from ash of various qualities or even whole coals.

HSV kategori
Forskningsprogram
Processmetallurgi; Fysik
Identifikatorer
urn:nbn:se:ltu:diva-12174 (URN)10.1016/j.minpro.2005.11.008 (DOI)000236788500004 ()2-s2.0-33645243068 (Scopus ID)b42e9150-a1a8-11db-8975-000ea68e967b (Lokal ID)b42e9150-a1a8-11db-8975-000ea68e967b (Arkivnummer)b42e9150-a1a8-11db-8975-000ea68e967b (OAI)
Merknad
Validerad; 2006; 20070111 (ysko)Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Zelent, B., Yano, T., Ohlsson, P.-I., Smith, M., Paul, J. & Vanderkooi, J. (2005). Optical spectra of lactoperoxidase as a function of solvent (ed.). Paper presented at . Biochemistry, 44(48), 15953-15959
Åpne denne publikasjonen i ny fane eller vindu >>Optical spectra of lactoperoxidase as a function of solvent
Vise andre…
2005 (engelsk)Inngår i: Biochemistry, ISSN 0006-2960, E-ISSN 1520-4995, Vol. 44, nr 48, s. 15953-15959Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The iron of lactoperoxidase is predominantly high-spin at ambient temperature. Optical spectra of lactoperoxidase indicate that the iron changes from high-spin to low-spin in the temperature range from room temperature to 20 K. The transformation is independent of whether the enzyme is in glycerol/water or solid sugar glass. Addition of the inhibitor benzohydroxamic acid increases the amount of the low-spin form, and again the transformation is independent of whether the protein is in an aqueous solution or a nearly anhydrous sugar. In contrast to lactoperoxidase, horseradish peroxidase remains high-spin over the temperature excursion in both solvents and with addition of benzohydroxamic acid. We conclude that details of the heme pocket of lactoperoxidase allow ligation changes with temperature that are dependent upon the apoprotein but independent of solvent fluctuations. At low pH, lactoperoxidase shows a solvent-dependent transition; the high-spin form is predominant in anhydrous sugar glass, but in the presence of water, the low-spin form is also present in abundance. The active site of lactoperoxidase is not as tightly constrained at low pH as at neutrality, though the enzyme is active over a wide pH range.

HSV kategori
Forskningsprogram
Fysik
Identifikatorer
urn:nbn:se:ltu:diva-11624 (URN)10.1021/bi0513655 (DOI)000233704900034 ()2-s2.0-28544450157 (Scopus ID)aa2107b0-ac89-11db-aeba-000ea68e967b (Lokal ID)aa2107b0-ac89-11db-aeba-000ea68e967b (Arkivnummer)aa2107b0-ac89-11db-aeba-000ea68e967b (OAI)
Merknad
Validerad; 2005; 20070125 (ysko)Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Sandström, Å., Shchukarev, A. & Paul, J. (2005). XPS characterisation of chalcopyrite chemically and bio-leached at high and low potential (ed.). Paper presented at . Minerals Engineering, 18(5), 505-515
Åpne denne publikasjonen i ny fane eller vindu >>XPS characterisation of chalcopyrite chemically and bio-leached at high and low potential
2005 (engelsk)Inngår i: Minerals Engineering, ISSN 0892-6875, E-ISSN 1872-9444, Vol. 18, nr 5, s. 505-515Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Leaching of chalcopyrite in sulphuric acid media has been investigated under constant redox potential conditions in solution. The leaching residues were analysed by X-ray diffraction and X-ray photoelectron spectroscopy. The leaching was performed at two different levels of redox potential, 420 mV and 600 mV (Pt vs. Ag, AgCl), at 65 °C. Both bioleaching and chemical leaching were investigated. The bioleaching was continuous, with a culture of the extremely thermophilic microorganism Sulfolobus metallicus. The high redox potential experiment was a "normal" bioleaching experiment; i.e., normal air flow, etc., the redox potential obtained at steady state was 600 mV and the low redox condition was achieved by a reduced airflow and additions of a sodium sulphite solution. The chemical leaching was done as a redox titration with potassium permanganate as oxidising agent to maintain the redox potential at 600 mV and 420 mV, respectively. Chalcopyrite leaching was greatly enhanced at the lower redox potential for both types of leaching, but especially during chemical leaching, which also resulted in large amounts of elemental sulphur. Passivation of the leaching at high redox potential was followed by a concomitant precipitation of large amounts of jarosite. Bioleaching resulted in a more complete sulphur oxidation to sulphate, even at low redox potential. It is thus concluded that passivation during chalcopyrite leaching is caused by jarosite and not elemental sulphur.

HSV kategori
Forskningsprogram
Processmetallurgi; Fysik
Identifikatorer
urn:nbn:se:ltu:diva-5071 (URN)10.1016/j.mineng.2004.08.004 (DOI)2-s2.0-14844295044 (Scopus ID)31686590-a1a6-11db-8975-000ea68e967b (Lokal ID)31686590-a1a6-11db-8975-000ea68e967b (Arkivnummer)31686590-a1a6-11db-8975-000ea68e967b (OAI)
Merknad
Validerad; 2005; 20070111 (ysko)Tilgjengelig fra: 2016-09-29 Laget: 2016-09-29 Sist oppdatert: 2018-07-10bibliografisk kontrollert
Sandström, Å., Paul, J., Paul, M., Aycik, S. G., Seferinoglu, M. & Smith, M. (2004). Acid leaching of ash from wood, asphaltite and lignite combustion: trace element occurences (ed.). In: (Ed.), (Ed.), American Chemical Society, 228th National Meeting: . Paper presented at American Chemical Society National Meeting : 22/08/2004 - 26/08/2004. Washington, DC: American Chemical Society (ACS)
Åpne denne publikasjonen i ny fane eller vindu >>Acid leaching of ash from wood, asphaltite and lignite combustion: trace element occurences
Vise andre…
2004 (engelsk)Inngår i: American Chemical Society, 228th National Meeting, Washington, DC: American Chemical Society (ACS), 2004Konferansepaper, Meeting abstract (Annet vitenskapelig)
Abstract [en]

The leaching of ash in sulfuric acid (pH 1.0, 25EC, S/L 1:10) was studied as a function of time. Data for the extraction of trace elements are presented. The study embraced ash from the combustion of two Turkish lignites (Yata?an and Tunçbilek), one asphaltite (Silopi) and the briquettes of Swedish softwood sawmill residues (Fränsta). Conclusions are drawn regarding suitable residence times for an industrial washing process as well as the chemical nature of trace elements in the untreated ashes. The kinetics of trace element (Cd, Co, Cr, Cu, Mo, Ni, V and Zn) dissolution followed a shrinking core model and extended times (> 32 h) were required to reach maximum extraction from the ashes. Comparisons with data for the dissolution of dominant ions point at association with aluminum or iron containing phases (clays). Th and U reached high extraction yields after 8 h in solution, which suggests either surface association or association with rapidly dissolved Ca or Mg containing phases. Time-dependent Ba and Pb dissolution was observed below the limit set by the solubility of the corresponding sulfides.

sted, utgiver, år, opplag, sider
Washington, DC: American Chemical Society (ACS), 2004
Serie
Abstracts of Papers of the American Chemical Society, ISSN 0065-7727
HSV kategori
Forskningsprogram
Processmetallurgi; Fysik
Identifikatorer
urn:nbn:se:ltu:diva-32576 (URN)71cf0c10-8c48-11db-8975-000ea68e967b (Lokal ID)71cf0c10-8c48-11db-8975-000ea68e967b (Arkivnummer)71cf0c10-8c48-11db-8975-000ea68e967b (OAI)
Konferanse
American Chemical Society National Meeting : 22/08/2004 - 26/08/2004
Merknad
Godkänd; 2004; 20061212 (ysko)Tilgjengelig fra: 2016-09-30 Laget: 2016-09-30 Sist oppdatert: 2017-11-25bibliografisk kontrollert
Organisasjoner