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Larsson Mats,Solimanjad Naghi,Dahlberg Mikael,Takeda Yoshinubu,Kondoh Mikio 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1
Filling of the tool die directly influences dimensional tolerances and density variation. To minimize the variations in filling, both within different sections of the cavity and from part to part, are of great importance for produce high quality P/M parts. Filling of the tool die is also one of the limiting factors in the productivity in powder pressing. By using aeration filling in combination with bonded powder mixes, both weight scatter and productivity can be improved. In this presentation results are presented showing the benefit of using aeration filling for different types of powders
Ilaria Cristofolini,Nicolò Corsentino,Alberto Molinari,Mats Larsson 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.
In the conventional press and sinter process, dimensional change on sintering determines the precision of the final parts, providingthat a good dimensional precision of green parts is ensured. Anisotropic dimensional change on sintering may be detrimental to theprecision of Powder Metallurgy (PM) parts, and it should be considered in the design step. The effect of material and geometry onthe anisotropic dimensional change is studied in this work. Four different iron alloys and five different geometries were considered. Dimensions were measured both on green and on sintered parts and the anisotropy of dimensional change was evaluated andcorrelated to the material and geometry. The effect of neglecting anisotropy in the design step was investigated, in terms ofdimensional tolerances, which can be obtained with different process capabilities. A model to describe the effect of material andgeometry on the anisotropic dimensional change is also being developed.
Maintenance of respiratory chain function in mouse hearts with severely impaired mtDNA transcription
Freyer, Christoph,Park, Chan Bae,Ekstrand, Mats I.,Shi, Yonghong,Khvorostova, Julia,Wibom, Rolf,Falkenberg, Maria,Gustafsson, Claes M.,Larsson, Nils-Gö,ran Oxford University Press 2010 Nucleic acids research Vol.38 No.19
<P>The basal mitochondrial transcription machinery is essential for biogenesis of the respiratory chain and consists of mitochondrial RNA polymerase, mitochondrial transcription factor A (TFAM) and mitochondrial transcription factor B2. This triad of proteins is sufficient and necessary for mtDNA transcription initiation. Abolished mtDNA transcription caused by tissue-specific knockout of TFAM in the mouse heart leads to early onset of a severe mitochondrial cardiomyopathy with lethality within the first post-natal weeks. Here, we describe a mouse model expressing human TFAM instead of the endogenous mouse TFAM in heart. These rescue mice have severe reduction in mtDNA transcription initiation, but, surprisingly, are healthy at the age of 52 weeks with near-normal steady-state levels of transcripts. In addition, we demonstrate that heavy-strand mtDNA transcription normally terminates at the termination-associated sequence in the control region. This termination is abolished in rescue animals resulting in heavy (H)-strand transcription of the entire control region. In conclusion, we demonstrate here the existence of an unexpected mtDNA transcript stabilization mechanism that almost completely compensates for the severely reduced transcription initiation in rescue hearts. Future elucidation of the underlying molecular mechanism may provide a novel pathway to treat mitochondrial dysfunction in human pathology.</P>
Reduced Weight Scatter with Bonded Powder Mixes
Edman Daniel,Alzati Luigi,Pozzi Giovanni,Frediani Carlo,Crosa Riccardo,Larsson Mats 한국분말야금학회 2006 한국분말야금학회 학술대회논문집 Vol.2006 No.1
Organically bonded P/M mixes have been developed to improve the stability of dimensional properties by reducing the segregation of the mix constituents and improving the filling characteristics. Robustness and reliability are key factors for the promotion of P/M as cost effective substitute of competing manufacturing technologies. Based on the production of four different belt pulleys, this paper presents the achievement of reduced weight scatter and close dimensional control realizable by using a StarmixTM that is organically bonded.