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| 2. |
- Elsik, Christine G., et al.
(författare)
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The Genome Sequence of Taurine Cattle : A Window to Ruminant Biology and Evolution
- 2009
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 324:5926, s. 522-528
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Tidskriftsartikel (refereegranskat)abstract
- To understand the biology and evolution of ruminants, the cattle genome was sequenced to about sevenfold coverage. The cattle genome contains a minimum of 22,000 genes, with a core set of 14,345 orthologs shared among seven mammalian species of which 1217 are absent or undetected in noneutherian (marsupial or monotreme) genomes. Cattle-specific evolutionary breakpoint regions in chromosomes have a higher density of segmental duplications, enrichment of repetitive elements, and species-specific variations in genes associated with lactation and immune responsiveness. Genes involved in metabolism are generally highly conserved, although five metabolic genes are deleted or extensively diverged from their human orthologs. The cattle genome sequence thus provides a resource for understanding mammalian evolution and accelerating livestock genetic improvement for milk and meat production.
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| 4. |
- Ander, Paul, et al.
(författare)
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CRUW Mechanical Pulping sub-project 1: Effect of different refining pressures and energy using spruce TMP pulps from Braviken
- 2010
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The mechanical pulping industry faces continued rising energy costs and increasing competition for raw material. In order to produce improved products based on mechanical pulp at lower energy consumption it is necessary to have a better understanding of the development of fundamental fibre properties during the processes. In particular, changes in fibre collapsibility, fibre fibrillation and fibre and surface development are of great interest. The overall goal of the CRUW Mechanical Pulping project is “Support development of more energy efficient mechanical pulping processes by increasing the knowledge on ultrastructural phenomena in mechanical pulping”. This project is working closely together with the Industrial Research College for Mechanical Pulping Technology bringing in the ultrastructural competence to more clearly understand and explain phenomena observed in these projects thus making it easier to develop new and improved processes to reduce energy consumption. This report presents results from CRUW Mechanical Pulping sub-project 1: ”Effect of different refining pressures and energy using spruce TMP pulps from Braviken”. The influence of temperature on the softening of lignin and hence improved (easier) fibre separation and treatment was noted earlier (Becker et al. 1977; Salmén 1984). Based on this knowledge, different process alternatives have been suggested to reduce energy demand for the refining process. One of the earliest publications on a technical system utilizing higher temperature and pressure was by Höglund et al. 1997 (Thermopulp). These results have been reproduced in many studies and are today considered general knowledge. There are however many practical problems with such a system. For example, the resulting very small refining gaps are difficult to control and it has therefore taken time to establish this technology in the industry. In the new TMP line at Braviken, the refiners are equipped to run at higher temperature/pressure than normal and it has therefore been interesting to study these pulps in order to explain the effects on pulp/fibres at an ultrastructural level. It should be noted that in a fibre-water-steam system, temperature and pressure are not independent variables and higher pressure means higher temperature and vice versa
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| 5. |
- Ander, Paul, et al.
(författare)
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Sub-project 10: CRUW Mechanical Pulping Enzyme treatment of chips for energy reduction in TMP
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In order to evaluate the possibilities of using enzymes for pre-treating softwood chips as a means of lowering the energy demand in mechanical pulping, impregnation and refining trials were performed using a set of different enzymes. The enzymes tested pectinase, xylanase and mannanase gave increased sugar release in the impregnation trials indicating that most of the sugar released occurred in the first 60 minutes and that activities thereafter seemed to level off. Refining trials using a small Wing refiner showed that for chips treated for 60 minutes with pectinase, xylanase and mannanase no energy savings to a given freeness level was observed. The property development was similar to that of reference pulps in the case of pectinase and xylanase while for chips treated with mannanase a less favourable development of the tensile index was noted. For chips treated for two hours, using xylanase or pectinase, energy savings could be observed for pectinase treated chips down to a freeness level of 200 CSF. However when refined further, the properties approached those of the reference pulp. Considering the much higher enzymatic activity reached when the initial fibre material was further disintegrated it is assumed that the possibilities for enzymes to attack desired structures of the intact fibre wall may have been too few even in the case of Impressafiner treated material.
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| 6. |
- Daniel, Geoffrey, et al.
(författare)
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Development of fiber properties in full scale HC and LC refining
- 2016
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Konferensbidrag (refereegranskat)abstract
- The aim of this work was to evaluate in more detail how fibers are developed during high consistency (HC) and low consistency (LC) refining. Three TMP mainline processes in mill operations were investigated for two configurations, one with only HC refining and the other with HC refining followed by LC refining. LC refining gave a similar increase in tensile index with increasing specific energy for the three lines, despite differences in the fiber property profiles of the feed pulps. At a given tensile index, LC refined pulps had a lower light scattering coefficient compared with only HC refining in the respective TMP line, but similar fiber length, strain at break, tear index and freeness. For two of the three lines, tensile index increased more with specific energy in LC than in HC refining. Whether installation of LC refining in a TMP line improves energy efficiency or not, depends on which pulp property(ies) the efficiency is related to, and also on the possibilities to optimize efficiency in the HC stages. Fiber curl decreased significantly for all LC refiners and remained unchanged or increased with higher energy in HC refining, although samples were tested after hot disintegration. Thus, the decrease of fiber curl contributed to the increase in tensile index in LC refining. When assessing the performance of LC refiners, fiber curl needs to be considered. Other fiber properties developed in different ways in HC and LC refining, resulting in different fiber property profiles for the two configurations.
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| 7. |
- Daniel, Geoffrey, et al.
(författare)
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Energy consumption in refining of Scots pine and Norway spruce TMP is governed by fibre morphology and ultrastructure
- 2009
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Ingår i: SPCI meddelande / The Swedish Association of Pulp and Paper Engineers. - 0280-6800. ; , s. 82-86
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Konferensbidrag (refereegranskat)abstract
- Studies on the different behaviour of Scots pine and Norway spruce during thermomechanical pulping were conducted to find reasons for explaining the greater energy consumption of pine. Well characterized wood samples from clear-cut trees and thinnings were used in pilot scale trials to produce highly characterized pulps. Structural and topochemical differences found between pine and spruce likely to have a strong negative impact on energy included: i) presence of a greater proportion of latewood fibres in pine annual rings with thick secondary cell walls and concomitant reduced fibre collapsibility; ii) ultrastructural differences in the location of fractures at the fibre secondary wall level during primary refining with pine showing greater resistance to refining although it defibrated easier than spruce; iii) that fibre separation and fibre development were sequential processes in pine and not concurrent as in spruce; and iv) the greater amounts of extractives in pine and their redistribution onto the surfaces of fibres and fines during processing
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| 8. |
- Daniel, Geoffrey, et al.
(författare)
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Inocula selection in microbial fuel cells based on anodic biofilm abundance of Geobacter sulfurreducens
- 2016
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier BV. - 1004-9541. ; 24, s. 379-387
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Tidskriftsartikel (refereegranskat)abstract
- Microbial fuel cells (MFCs) rely on microbial conversion of organic substrates to electricity. The optimal performance depends on the establishment of a microbial community rich in electrogenic bacteria. Usually this microbial community is established from inoculation of the MFC anode chamber with naturally occurring mixed inocula. In this study, the electrochemical performance of MFCs and microbial community evolution were evaluated for three inocula including domestic wastewater (DW), lake sediment (LS) and biogas sludge (BS) with varying substrate loading (L-sub) and external resistance (R-ext) on the MFC. The electrogenic bacterium Geobacter sulfurreducens was identified in all inocula and its abundance during MFC operation was positively linked to the MFC performance. The LS inoculated MFCs showed highest abundance (18%+/- 1%) of G. sulfurreducens, maximum current density [I-max = (690 +/- 30) mA.m(-2)] and coulombic efficiency (CE = 29% +/- 1%) with acetate as the substrate. I-max and CE increased to (1780 +/- 30) mA.m(-2) and 58% +/- 1%, respectively, after decreasing the R-ext from 1000 Omega to 200 Omega, which also correlated to a higher abundance of G. sulfurreducens (21% +/- 0.7%) on the MFC anodic biofilm. The data obtained contribute to understanding the microbial community response to L-sub and R-ext for optimizing electricity generation in MFCs. (c) 2015 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.
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