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Salh, Roushdey
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Publications (10 of 38) Show all publications
Smijesh, N., Zhang, X., Fischer, P., Muschet, A., Salh, R., Tajalli, A., . . . Veisz, L. (2019). Contrast improvement of sub-4 fs laser pulses using nonlinear elliptical polarization rotation. Optics Letters, 44(16), 4028-4031
Open this publication in new window or tab >>Contrast improvement of sub-4 fs laser pulses using nonlinear elliptical polarization rotation
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2019 (English)In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 44, no 16, p. 4028-4031Article in journal (Refereed) Published
Abstract [en]

Temporal-intensity contrast is crucial in intense laser-matter interaction to circumvent the undesirable expansion of steep high-density plasma prior to the interaction with the main pulse. Nonlinear elliptical polarization rotation in an argon filled hollow-core fiber is used here for cleaning pedestals/satellite pulses of a chirped-pulse-amplifier based Ti: Sapphire laser. This source provides similar to 35 mu J energy and sub-4-fs duration, and the process has >50% internal efficiency, more than the most commonly used pulse cleaning methods. Further, the contrast is improved by 3 orders of magnitude when measured after amplifying the pulses to 16 TW using non-collinear optical parametric chirped pulse amplification with a prospect to even further enhancement.

Place, publisher, year, edition, pages
Optical Society of America, 2019
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-162848 (URN)10.1364/OL.44.004028 (DOI)000481541400031 ()31415539 (PubMedID)
Available from: 2019-09-09 Created: 2019-09-09 Last updated: 2019-09-09Bibliographically approved
Grimm, A., Etula, J., Salh, R., Kalén, G., Segerström, M., Brücher, J., . . . Larsson, S. H. (2019). Slagging and fouling characteristics during co-combustion of Scots pine bark with low-temperature dried pulp and paper mill chemical sludge. Fuel processing technology, 193, 282-294
Open this publication in new window or tab >>Slagging and fouling characteristics during co-combustion of Scots pine bark with low-temperature dried pulp and paper mill chemical sludge
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2019 (English)In: Fuel processing technology, ISSN 0378-3820, E-ISSN 1873-7188, Vol. 193, p. 282-294Article in journal (Refereed) Published
Abstract [en]

This paper shows how chemical sludge (CS) generated during wastewater treatment at a paperboard mill can be quickly dried at low-temperature and employed in bark-fired boilers to reduce slagging and corrosion problems. By using a cyclone-dryer operated at an inlet-air velocity of 110 m/s and a temperature of 90 degrees C, the dry-matter content of CS was increased from approximately 19 to 82%. The residence time of CS inside the cyclone was approximately 2 s when using the inlet-air velocity mentioned above. Disaggregation of the feedstock caused by collisions with the cyclone wall and between particles played a crucial role in enhancing the efficiency of heat and mass transfer. Three co-pelletized mixtures of Scots pine bark (SPB) and dried-CS were combusted in a 40 kW fixed-bed burner. Flue gas analysis was performed with a gas analyser. Coarse and fine ash were analysed by SEM-EDS and XRD. NO,, and SO2 emissions increased with increasing amount of CS in the mixtures. Mono combustion of SPB resulted in a large quantity of slag (i.e., molten ash) with a high degree of sintering (i.e., hardness of the slag), and ash deposits formed on heat transfer surfaces were rich in K2SO4 and KCI. Mixtures of SPB and CS were less prone to slagging, and the amount of alkali chloride in the deposits was reduced in favour of alkali sulphate formation.

Place, publisher, year, edition, pages
Elsevier, 2019
Keywords
Pulp and paper mill sludge, Drying, Combustion, NOx, SO2, Slag, Fouling
National Category
Energy Engineering Energy Systems
Research subject
Physics
Identifiers
urn:nbn:se:umu:diva-161685 (URN)10.1016/j.fuproc.2019.05.019 (DOI)000473842100029 ()2-s2.0-85066129785 (Scopus ID)
Projects
Bio4Energy
Funder
Swedish Research Council Formas, 213-2014-182Bio4Energy
Available from: 2019-08-06 Created: 2019-08-06 Last updated: 2019-11-04Bibliographically approved
Salh, R. (2013). Spectroscopic properties of HALS doped polycarbonate by fluorescence spectroscopy. Physical Review & Research International, 3(2), 42-54
Open this publication in new window or tab >>Spectroscopic properties of HALS doped polycarbonate by fluorescence spectroscopy
2013 (English)In: Physical Review & Research International, ISSN 2231-1815, Vol. 3, no 2, p. 42-54Article in journal (Refereed) Published
Abstract [en]

The fluorescence and fluorescence excitation spectra of pure and doped polycarbonate (PC) depending on hindered-amine light stabilizers (HALS: Tinuvin 770 and Tinuvin 123) concentration and different processing conditions have been studied. Non-processed PC has no emission band in the visible range but processed PC with additives show visible fluorescence bands between 400–470 nm. It suggested that PC undergoes a kind of degradation process which lead to the fluorescence emission caused by the transitions from the new distortion-related localized states (defect states) created by processing and the additives. Such defects lead also to the emergence of a new band in the excitation and emission spectra at lower energies, where the symmetry of the bands break near. The intensity of these bands drastically depends on the sample treatment where the luminescence intensity quantitatively characterizes the concentration of defect radicals. An increase in screw speed resulted in an increase in specific mechanical energy (SME), higher SME led to a remarkable macromolecular degradation.

Place, publisher, year, edition, pages
Sciencedomain international, 2013
Keywords
Luminescence spectroscopy; polycarbonate; tinuvin; UV-light stabilizer
National Category
Physical Sciences
Identifiers
urn:nbn:se:umu:diva-66980 (URN)
Available from: 2013-03-09 Created: 2013-03-09 Last updated: 2018-06-08Bibliographically approved
Salh, R. (2011). Concentration and annealing effects on luminescence properties of ion implanted silica layers. Journal of Atomic, Molecular, and Optical Physics, 2011, 326368
Open this publication in new window or tab >>Concentration and annealing effects on luminescence properties of ion implanted silica layers
2011 (English)In: Journal of Atomic, Molecular, and Optical Physics, ISSN 1687-9228, Vol. 2011, p. 326368-Article in journal (Refereed) Published
Abstract [en]

The development of optoelectronic or even photonic devices based on silicon technology is still a great challenge. Silicon and itsoxide do not possess direct optical transitions and, therefore, are not luminescent. The remaining weak light emission is based onintrinsic and extrinsic defect luminescence. Thus the investigations are extended to ion implantation into silica layers, mainly onover-stoichiometric injection or isoelectronic substitution of both the constituents silicon or oxygen, that is, by ions of the groupIV (C, Si, Ge, Sn, Pb) or the group VI (O, S, Se). The samples have been used were 500nm thick thermally grown amorphous SiO2layers, wet oxidized at 1100◦C on a crystalline Si substrate. The ion implantations were performed with different energies but allwith a uniformdose of 5×1016 ions/cm2. Such implantations produce new luminescence bands, partially with electronic-vibronictransitions and related multimodal spectra. Special interest should be directed to lowdimension nanocluster formation in silicalayers. Implantations of group IV elements show a general increase of the luminescence in the violet-blue region and implantationsof group VI elements lead to an increase in the yellow-red spectral region. Comparing cathodoluminescence, photoluminescence,and electroluminescence still too small luminescence quantum yields are obtained.

Place, publisher, year, edition, pages
Hindawi Publishing Corporation, 2011
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-50228 (URN)10.1155/2011/326368 (DOI)
Available from: 2011-12-01 Created: 2011-12-01 Last updated: 2018-06-08Bibliographically approved
Salh, R. (2011). Defect related luminescence in silicon dioxide network: a review. In: Sukumar Basu (Ed.), Crystalline Silicon: Properties and Uses (pp. 135-172). Rijeka: InTech
Open this publication in new window or tab >>Defect related luminescence in silicon dioxide network: a review
2011 (English)In: Crystalline Silicon: Properties and Uses / [ed] Sukumar Basu, Rijeka: InTech , 2011, p. 135-172Chapter in book (Refereed)
Place, publisher, year, edition, pages
Rijeka: InTech, 2011
National Category
Materials Engineering
Identifiers
urn:nbn:se:umu:diva-50190 (URN)978-953-307-587-7 (ISBN)
Available from: 2011-11-29 Created: 2011-11-28 Last updated: 2018-06-08Bibliographically approved
Salh, R. (2011). Nucleation kinetics in deionized charged colloidal suspension. Journal of Non-Crystalline Solids, 357, 1044-1050
Open this publication in new window or tab >>Nucleation kinetics in deionized charged colloidal suspension
2011 (English)In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 357, p. 1044-1050Article in journal (Refereed) Published
Abstract [en]

A systematic experimental study on the nucleation, crystallization and crystal-growth of one-componentcharged colloidal particles (122 nm diluted in pure water with densities between 0.5 μm−3bnpb5 μm−3) ispresent by means of time resolved static light scattering spectroscopy revealing the heterogeneousand homogenous nature of the crystallization. The interactions between the charged colloidal particles aresufficiently strong to cause crystallization which described in terms of Debye-Hückel approximation. Crystallization starts always with the formation of compressed structurally heterogeneous precursordomains. The results show that the heterogeneous nucleation at the cell walls starts simultaneously with thehomogeneous bulk nucleation and the rate density of the heterogeneous nucleation appears slightly higher. Ithas been also found that the overall crystallization consists of at least a two-step nucleation process involvingformation of early stage nuclei or crystal precursor then followed by the main crystallization. The inductiontime, the number density of nuclei and the growth rate of crystals, is strongly dependent on particleconcentration and on whether the nucleation are homogeneous in cell center or heterogeneous on cell walls.

Place, publisher, year, edition, pages
Elsevier, 2011
Keywords
Colloids, Crystal growth, Nucleation, Light scattering
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-50227 (URN)10.1016/j.jnoncrysol.2010.11.042 (DOI)
Available from: 2011-12-01 Created: 2011-12-01 Last updated: 2018-06-08Bibliographically approved
Salh, R. (2011). Silicon nanocluster in silicon dioxide: Cathodoluminescence, energy dispersive X-ray analysis, infrared spectroscopy studies. In: Sukumar Basu (Ed.), Crystalline Silicon: Properties and Uses (pp. 173-218). Rijeka: InTech
Open this publication in new window or tab >>Silicon nanocluster in silicon dioxide: Cathodoluminescence, energy dispersive X-ray analysis, infrared spectroscopy studies
2011 (English)In: Crystalline Silicon: Properties and Uses / [ed] Sukumar Basu, Rijeka: InTech , 2011, p. 173-218Chapter in book (Refereed)
Place, publisher, year, edition, pages
Rijeka: InTech, 2011
National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:umu:diva-50226 (URN)978-953-307-587-7 (ISBN)
Available from: 2011-12-01 Created: 2011-12-01 Last updated: 2018-06-08Bibliographically approved
Matoussi, A., Ben Nasr, F., Boufaden, T., Salh, R., Fakhfakh, Z., Guermazi, S., . . . Fitting, H.-J. (2010). Luminescent properties of GaN films grown on porous silicon substrate. Journal of Luminescence, 130, 399-403
Open this publication in new window or tab >>Luminescent properties of GaN films grown on porous silicon substrate
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2010 (English)In: Journal of Luminescence, ISSN 0022-2313, E-ISSN 1872-7883, Vol. 130, p. 399-403Article in journal (Refereed) Published
National Category
Physical Sciences
Identifiers
urn:nbn:se:umu:diva-50234 (URN)10.1016/j.jlumin.2009.10.003 (DOI)
Available from: 2011-12-01 Created: 2011-12-01 Last updated: 2018-06-08Bibliographically approved
Fitting, H.-J., Fitting Kourkoutis, L., Salh, R., Kolesnikova, E., Zamoryanskaya, M., von Czarnowski, A. & Schmidt, B. (2010). Silicon cluster aggregation in silica layers. Solid State Phenomena, 156-158, 529-533
Open this publication in new window or tab >>Silicon cluster aggregation in silica layers
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2010 (English)In: Solid State Phenomena, ISSN 1012-0394, E-ISSN 1662-9779, Vol. 156-158, p. 529-533Article in journal (Refereed) Published
National Category
Physical Sciences
Identifiers
urn:nbn:se:umu:diva-50232 (URN)10.4028/www.scientific.net/SSP.156-158.529 (DOI)
Available from: 2011-12-01 Created: 2011-12-01 Last updated: 2018-06-08Bibliographically approved
Fitting, H.-J., Fitting Kourkoutis, L., Salh, R., Zamoryanskaya, M. & Schmidt, B. (2010). Silicon nanocluster aggregation in SiO2:Si layers. Physica status solidi. A, Applied research, 207(1), 117-123
Open this publication in new window or tab >>Silicon nanocluster aggregation in SiO2:Si layers
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2010 (English)In: Physica status solidi. A, Applied research, ISSN 0031-8965, E-ISSN 1521-396X, Vol. 207, no 1, p. 117-123Article in journal (Refereed) Published
National Category
Physical Sciences
Identifiers
urn:nbn:se:umu:diva-50233 (URN)10.1002/pssa.200925201 (DOI)
Available from: 2011-12-01 Created: 2011-12-01 Last updated: 2018-06-08Bibliographically approved
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