| 1. |
|
|
| 2. |
- Ahmed, Sheikh Ali, et al.
(författare)
-
Anatomical properties and process parameters affecting blister/blow formation in densified European aspen and downy birch sapwood boards by thermo-hygro-mechanical compression
- 2013
-
Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 48:24, s. 8571-8579
-
Tidskriftsartikel (refereegranskat)abstract
- Approximately, 13.5 % of the standing volume of productive forest land in Sweden is covered by birch and aspen, which provides the vast potential to produce value-added products such as densified wood. This study shows whether it is possible to densify those species with a thermo-hygro-mechanical (THM) process using heat, steam, and pressure. In this process, transverse compression on thin European aspen (Populus tremula) and downy birch (Betula pubescens) boards was performed at 200 ºC with a maximum steam pressure of 550 kPa. To obtain a theoretical 50 % compression set, the press’s maximum hydraulic pressure ranged from 1.5 to 7.3 MPa. Preliminary tests showed that ~75 % of the birch boards produced defects (blisters/blows) while only 25 % of the aspen boards did. Mainly, radial delamination associated with internal checks in intrawall and transwall fractures caused small cracks (termed blisters) while blows are characterized by relatively larger areas of delamination visible as a bumpy surface on the panel. Anatomical investigations revealed that birch was more prone to those defects than aspen. However, those defects could be minimized by increasing the pre-treatment time during the THM processing.
|
|
| 3. |
- Al-Hamdi, A. M., et al.
(författare)
-
Photocatalytic degradation of phenol in aqueous solution by rare earth-doped SnO2 nanoparticles
- 2014
-
Ingår i: Journal of Materials Science. - : Springer Science+Business Media B.V.. - 0022-2461 .- 1573-4803. ; 49:14, s. 5151-5159
-
Tidskriftsartikel (refereegranskat)abstract
- The influence of heterogeneous semiconductors on the photodegradation of phenol in water was investigated using doped tin dioxide (SnO2) nanoparticles. Photocatalysts of SnO2 were synthesized with lanthanum (La), cerium (Ce), and neodymium (Nd) dopants. These photocatalysts were synthesized from tin tetrachloride by sol-gel method with different dopant concentrations, and its photocatalytic degradation was investigated up to 0.8 % under UV-A light in aqueous suspensions. The photocatalytic oxidation reactions were studied by varying photocatalyst composition, light intensity, reaction time, pH of the reaction medium, and phenol concentration. It was found that the photocatalytic activity of rare earth-doped SnO2 for phenol decomposition under UV light irradiation was considerably higher than that of pure SnO2 nanoparticles. The experimental results also indicate that more than 95 % phenol was effectively oxidized in the presence of an aqueous suspension of La: SnO2 nanoparticles within 120 min of UV light irradiation.
|
|
| 4. |
- Al-Hinai, M. H., et al.
(författare)
-
Phase transformation behavior of zinc metastannates obtained by aqueous precipitation at different temperatures
- 2014
-
Ingår i: Journal of Materials Science. - : Springer-Verlag New York. - 0022-2461 .- 1573-4803. ; 49:20, s. 7282-7289
-
Tidskriftsartikel (refereegranskat)abstract
- Phase transformation studies in ZnO-SnO2 system from zinc metastannate (ZnSnO3) to zinc orthostannate (Zn2SnO4) with annealing temperature are reported. Non-centrosymmetric oxides show unique symmetry dependent and spontaneous polarization properties, which are technologically important. ZnSnO3 particles were synthesized by a simple aqueous synthesis at low temperatures designed with the assistance of potential-pH diagrams. ZnSnO3 particles synthesized at 4 A degrees C are more porous losing the ilmenite structure upon annealing at 200 A degrees C, while the other samples prepared at higher temperatures (25-65 A degrees C) becomes amorphous at 300 A degrees C. The phase transformation into the inverse spinel orthostannate phase occurs around 750 A degrees C in all the samples.
|
|
| 5. |
- Amin, Gul, et al.
(författare)
-
Scale-up synthesis of ZnO nanorods for printing inexpensive ZnO/polymer white light-emitting diode
- 2012
-
Ingår i: Journal of Materials Science. - : Springer. - 0022-2461 .- 1573-4803. ; 47:11, s. 4726-4731
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, possibilities of scaling up the synthesis of zinc oxide (ZnO) nanorods (NRs) by the hydrothermal method have been explored. It was found that batches yielding several grams can easily be made using common and easily available materials. Further, a printable composition was fabricated by mixing the obtained ZnO NRs into a common solvent-based screen printable varnish. Scanning electron microscope, high-resolution transmission electron microscope, X-ray diffraction, UV–vis spectroscopy analysis of the scaled up batch indicated that the ZnO nanostructures were of NRs shape, well crystalline and having less defects. Using the ZnO NRs-based printable composition a device fabrication on a flexible substrate was demonstrated, producing a flexible light-emitting device being highly tolerant to bending.
|
|
| 6. |
- Andersons, J., et al.
(författare)
-
Modeling the effect of reinforcement discontinuity on the tensile strength of UD flax fiber composites
- 2011
-
Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 46:15, s. 5104-5110
-
Tidskriftsartikel (refereegranskat)abstract
- To exploit the potential of natural fibers as reinforcement of polymer matrix composites, aligned bast fiber composite materials are being produced and studied. Bast fiber reinforcement is discontinuous due to the limited length of natural fibers, which needs to be reflected in predictive models of mechanical properties of composites. The strength in tension in the fiber direction of an aligned flax fiber-reinforced composite is modeled assuming that a cluster of adjacent fiber discontinuities is the origin of fracture. A probabilistic model of tensile strength, developed for UD composites containing a microdefect, is applied. It follows from the theoretical analysis that the experimental tensile strength as a function the fiber volume fraction can be described with acceptable accuracy assuming the presence of a cluster of ca. 4 × 4 elementary fiber discontinuities
|
|
| 7. |
- Aslan, M., et al.
(författare)
-
Strength Variability of Single Flax Fibres
- 2011
-
Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 46
-
Tidskriftsartikel (refereegranskat)
|
|
| 8. |
- Berillo, Dmitry, et al.
(författare)
-
Preparation and physicochemical characteristics of cryogel based on gelatin and oxidised dextran
- 2014
-
Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 49:14, s. 4855-4868
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, a novel method of preparation of cryogels based on oxidised dextran (Ox.D) and gelatin (Gel) without sodium borohydride is proposed. The physico-chemical properties of obtained hydrogels were investigated. It was found that the stability of cryogels Ox.D-Gel is significantly depended on pH, and mechanical properties were improved after the freeze drying. The schemes of the reactions between Ox.D and Gel at different steps of the treatment of the material were suggested. According to H-1-NMR data, the Amadori rearrangement occurred under the step of cryogelation. The increase of cross-linking degree through the formation of additional Schiff's base group was observed as a result of incubation at high humidities or elevated temperature (60 A degrees C). The obtained cryogels can be used as biocompatible and biodegradable scaffolds for proliferation of cells or other biomedical applications.
|
|
| 9. |
- Dey, Kalpana R., et al.
(författare)
-
Synthesis and characterization of niobium doped hexagonal tungsten bronze in the systems, Cs(x)Nb(y)W(1-y)O(3)
- 2011
-
Ingår i: Journal of Materials Science. - : Springer Science and Business Media LLC. - 0022-2461 .- 1573-4803. ; 46:5, s. 1388-1395
-
Tidskriftsartikel (refereegranskat)abstract
- Samples of nominal compositions, Cs(0.25)Nb (y) W(1-y) O(3) and Cs(0.3)Nb (y) W(1-y) O(3) with 0.0 a parts per thousand currency sign y a parts per thousand currency sign 0.25 and 0.0 a parts per thousand currency sign y a parts per thousand currency sign 0.3 were synthesized using appropriate amounts of Cs(2)WO(4), WO(3) and WO(2) in evacuated and closed silica glass tubes at 800 A degrees C. The polycrystalline products contain hexagonal shaped crystals of up to 15 mu m diameter as long as y a parts per thousand currency sign 0.15. X-ray powder patterns of the samples reveal the formation of hexagonal tungsten bronze (HTB-I) type phase with y < 0.1. A mixture of HTB-I and an analogous less reduced hexagonal tungsten bronze (HTB-II) type phase is seen when y a parts per thousand yen 0.1. HTB-II content increases with increasing y, revealing close similarity to bronzoid type phases when y = x. Results of SEM/EDX analysis also support a partial substitution of tungsten by niobium in the HTB-I type phase. Infrared absorption and optical reflectivity data shows the effect of increasing amount of non-metallic phase for y > 0.1 and the effect of counterdoping by Nb(5+)/W(5+) substitution in the metallic HTB-I type phase for y a parts per thousand currency sign 0.1, respectively. Reinvestigations in the system Rb(0.3)Nb (y) W(1-y) O(3) (0.0 a parts per thousand currency sign y a parts per thousand currency sign 0.175) show similar results with increasing content of HTB-II type phase related with y.
|
|
| 10. |
- Dhawale, D, et al.
(författare)
-
Synthesis and characterizations of CdS nanorods by SILAR method : effect of film thickness
- 2011
-
Ingår i: Journal of materials science. Materials in electronics. - : Springer. - 0957-4522 .- 1573-482X. ; 46, s. 5009-5015
-
Tidskriftsartikel (refereegranskat)abstract
- In this investigation, we have successfully synthesized CdS nanorods by simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method. The effect of film thickness on the physico-chemical properties such as structural, morphological, wettability, optical, and electrical properties of CdS nanorods has been investigated. The XRD pattern revealed that CdS films are polycrystalline with hexagonal crystal structure. SEM and TEM images showed that CdS film surface are composed of spherical grains along with some spongy cluster and an increase in film thickness up to 1.23 μm causes the formation of matured nanorods having diameter 150–200 nm. The increases in water contact angle form 105° to 130° have been observed as film thickness increases from 0.13 to 1.23 μm indicating hydrophobic nature. The optical band gap was found to be increased from 2.02 to 2.2 eV with increase in film thickness. The films showed the semiconducting behavior with room temperature electrical resistivity in the range of 104–106 Ω cm and have n-type electrical conductivity.
|
|
