| 1. |
- Andrae, Anders, 1973, et al.
(författare)
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Uncertainty estimation by Monte Carlo Simulation applied to Life Cycle Inventory of Cordless Phones and Microscale Metallization Processes
- 2004
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Ingår i: IEEE Transactions on Electronics Packaging Manufacturing. ; 27:4, s. 233-245
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Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on uncertainty analysis, that is, how the input data uncertainty affects the output data uncertainty in small but realistic product systems is modeled. The motivation for the study is to apply the Monte Carlo simulation for uncertainty estimation in life cycle inventory and environmental assessment of microelectronics applications. This paper addresses the question whether there is an environmental advantage of using DECT phones instead of GSM phones in offices. The paper also addresses the environmental compatibility of Electrochemical Pattern Replication (ECPR) compared to classical photolithography based microscale metallization (CL) for pattern transfer. Both environmental assessments in this paper consider electricity consumption and CO2 emissions. The projects undertaken are two comparative studies of DECT phone/GSM phone and ECPR/CL respectively. The research method used was probabilistic uncertainty modelling with a limited number of inventory parameters used in the MATLAB tool. For the DECT/GSM study the results reflects the longer DECT technical life which is an environmental advantage. For the Electrochemical Pattern Replication (ECPR)/classical photolithography based microscale metallization (CL) study the results reflects the fewer number of process steps and the lower electricity consumption needed by the ECPR to reach the functional unit. The difference in results is large enough to be able to draw conclusions, as the processes with the highest electricity consumption within the system boundaries have been determined. Based on earlier work a straightforward method to include uncertainty for input life cycle inventory data is used to quantify the influence of realistic errors for input data in two microelectronic applications. The conclusion is that the ECPR technology is more electricity efficient than CL in producing one layer of copper on a silicon wafer having a diameter of 20.32 cm. The conclusion is that the longer technical life of a cordless DECT phone is reflected in an electricity/CO2 comparison with a GSM phone, if use in an office is considered. Reasonable uncertainty intervals used for the input life cycle inventory data for the studied DECT/GSM and ECPR/CL system does affect the outcome of calculation of emission of CO2 but not to the degree that conclusions are not valid.Different uncertainty intervals and probability distributions could apply for different types of data and the interrelated input data dependence should be investigated. Today there exist very few life cycle inventory (LCI) data with the range of uncertainty for input and output elements. It must be emphasized that the upcoming LCI databases should have standard deviation characterized LCI data just as the Swiss ecoinvent LCI database.More inventory parameters and probability distributions characteristic for microsystems could be included and error analysis should be applied to future life inventory methodology, especially for future packaging concepts such as System-In-a-Package and System-On-a-Chip comparisons.
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| 2. |
- Mo, Zhimin, et al.
(författare)
-
Integrating nano carbon tubes with microchannel cooler
- 2004
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Ingår i: Proceedings of The 6th IEEE CPMT International Symposium on High Density Packaging and Component Failure Anlaysis (HDP'4). ; 04:EX905, s. pp 373-376
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Konferensbidrag (refereegranskat)
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| 3. |
- Anderson, Johan, 1973, et al.
(författare)
-
A comparison of drift wave stability in stellarator and tokamak geometry
- 2002
-
Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 9:5, s. 1629-
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Tidskriftsartikel (refereegranskat)abstract
- The influence of plasma geometry on the linear stability of electrostatic ion-temperature-gradient driven drift modes (ITG modes) is investigated. An advanced fluid model is used for the ions together with Boltzmann distributed electrons. The derived eigenvalue equation is solved numerically. A comparison is made between an H – 1NF [Fusion Technol. 17, 123 (1990)] like stellarator equilibrium, a numerical tokamak equilibrium and the analytical s - alpha equilibrium. The numerical and the analytical tokamak are found to be in good agreement in the low inverse aspect ratio limit. The growth rates of the tokamak and stellarator are comparable whereas the modulus of the real frequency is substantially larger in the stellarator. The threshold in Ln/LT for the stellarator is found to be somewhat larger. In addition, a stronger stabilization of the ITG mode growth is found for large L n / R in the stellarator case.
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| 4. |
- Anderson, Johan, 1973
(författare)
-
Drift Waves in General Toroidal Equilibria
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the main concerns in fusion research is to understand the anomalously high transport in magnetically confined plasmas. In recent years, substantial progress in the understanding of transport in terms of drift waves in fusion plasmas has been achieved. It is at present an important issue to investigate the stability of drift waves in realistic toroidal geometries. Among the drift wave candidates for explaining the anomalous transport are the toroidal ITG-modes in the core and the resistive ITG-modes and the resistive ballooning modes in the edge. The effects of plasma shaping on magneto-hydrodynamic (MHD) modes have been thoroughly studied. However, the effects of plasma shaping on the drift waves are not well known. Empirically it is found that the overall effects of elongation on the energy confinement time is favorable with ~ kappa^0.5. In this thesis, the ITG-mode and the resistive edge mode stability in a non-circular tokamak geometry are studied. In particular, the effects of elongation and Shafranov shift are studied. In the core plasma a destabilization of the ITG-mode with increasing elongation is found whereas a stabilization is found in the edge region (or rather for peaked density profiles). Moreover, a comparison of the ITG-mode growth rates in the tokamak and stellarator equilibria is made. The growth rates for the tokamak and stellarator cases are comparable whereas the modulus of the real frequency is substantially larger in the stellarator. In addition, a stronger stabilization of the ITG mode growth is found for large Ln/R in the stellarator case. Finally, an analytical estimation of zonal flow generation including effects of elongation is presented. The results suggest that a strong excitation of zonal flows is obtained for peaked density profiles and close to marginal stability. However, in order draw more detailed conclusions of the effects of elongation on the global confinement time, a more extensive study using predictive transport simulations, which treats the edge and core transport processes self-consistently will be needed.
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| 5. |
- Anderson, Johan, 1973
(författare)
-
Drift waves in non-circular tokamak geometry
- 2000
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- One of the main concerns in fusion research is to understand the anomalously high transport in magnetically confined plasmas. In recent years, substantial progress in the understanding of transport in terms of drift waves in tokamaks has been achieved. It is at present an important issue to investigate the stability of drift waves in realistic tokamak geometries. Among the drift wave candidates for explaining the anomalous transport are the toroidal etai-modes in the core and the resistive etai-modes in the edge. In this thesis, the etai mode and the resistive edge mode stability in a non-circular tokamak geometry are studied. In particular, the effects of elongation and Shafranov shift are studied. The effects of plasma shaping on magnetohydrodynamic (MHD) modes have been thoroughly studied. However, the effects of plasma shaping on the drift waves are not well known. Empirically it is found that the overall effects of elonagtion is favourable.In the core plasma a stabilization of the etai modes with increasing elongation is found. It has been found that the spectrum of the unstable etai-modes is shifted toward shorter wavelengths with increasing elongation.In the edge (or rather for peaked density profiles) the effects of elongation on the etai-mode are, however, stabilizing. For edge parameters a stabilizing effect of elongation on the resistive modes is also found and the collisional effects on the etai-modes are rather weak. It is shown that the effects of ion temperature fluctuations on the resistive ballooning modes are stabilizing and this may further enhanced by elongation effects. In particular, it is found that the resistive ballooning mode is stabilized by finite Larmor radius effects already for etai
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| 6. |
- Anderson, Johan, 1973, et al.
(författare)
-
Effects of cross-sectional elongation on the resistive edge modes
- 2001
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Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 8, s. 180-
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Tidskriftsartikel (refereegranskat)abstract
- Resistive edge modes in a shifted noncircular tokamak geometry are investigated in the electrostatic limit. The reduced Braghinskii equations are used as a model for the electrons and an advanced fluid model for the ions. An eigenvalue problem is derived from these equations which is solved numerically. It is found that the resistive ballooning modes are stabilized by plasma elongation forpeaked density profiles. In addition, it is found that the resistive ITG mode may be either stabilized or destabilized by elongation depending on the collision frequency.
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| 7. |
- Anderson, Johan, 1973, et al.
(författare)
-
Effects of non-circular tokamak geometry on ion-temperature-gradient driven modes
- 2000
-
Ingår i: Plasma Phys. Contr. Fusion. - : IOP Publishing. ; 42, s. 545-
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Tidskriftsartikel (refereegranskat)abstract
- The influence of plasma elongation and Shafranov shift on the stability of electrostatic ion-temperature-gradient driven modes (ηi-modes) is investigated. An advanced fluid model is used for the ions together with Boltzmann distributed electrons. The derived eigenvalue equation is solved both analytically, in the strong ballooning limit, and numerically. It is found that the effects of elongation change from stabilizing, for peaked density profiles, to destabilizing in the flat density regime. In addition, it is shown that the maximum growth rate is shifted towardsshorter wavelengths as the elongation increases. The effects of shaping on tokamak stability are exemplified with data from a Joint European Torus (JET) high-performance mode discharge.
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| 8. |
- Anderson, Johan, 1973, et al.
(författare)
-
Zonal flow generation in ITG turbulence
- 2002
-
Ingår i: Physics of Plasmas. - : AIP Publishing. - 1070-664X .- 1089-7674. ; 9, s. 4500-
-
Tidskriftsartikel (refereegranskat)abstract
- In the present work the zonal flow (ZF) growth rate in toroidal ion-temperature-gradient (ITG) mode turbulence including the effects of elongation is studied analytically. The scaling of the ZF growth with plasma parameters is examined for typical tokamak parameter values. The physical model used for the toroidal ITG driven mode is based on the ion continuity and ion temperature equations whereas the ZF evolution is described by the vorticity equation. The results indicate that a large ZFgrowth is found close to marginal stability and for peaked density profiles and these effects may be enhanced by elongation.
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| 9. |
- Andrae, Anders, 1973, et al.
(författare)
-
Uncertainty estimation by Monte Carlo simulation applied to life cycle inventory of cordless phones and microscale metallization processes
- 2004
-
Ingår i: IEEE transactions on electronics packaging manufacturing (Print). - 1521-334X .- 1558-0822. ; 27:4, s. 233-245, s. 206-217
-
Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on uncertainty analysis, that is, how the input data uncertainty affects the output data uncertainty in small but realistic product systems. The motivation for the study is to apply the Monte Carlo simulation for uncertainty estimation in life cycle inventory and environmental assessment of microelectronics applications. The present paper addresses the question whether there is an environmental advantage of using digital enhanced cordless telecommunications (DECT) phones instead of global system for mobile (GSM) phones in offices. This paper also addresses the environmental compatibility of electrochemical pattern replication (ECPR) compared to classical photolithography-based microscale metallization (CL) for pattern transfer. Both environmental assessments in this paper consider electricity consumption and CO2 emissions and the projects undertaken are two comparative studies of DECT phone/GSM phone and ECPR/CL, respectively. The research method used was probabilistic uncertainty modeling with a limited number of inventory parameters used in the MATLAB tool. For the DECT/GSM study the results reflects the longer DECT technical life which is an environmental advantage. For the electrochemical pattern replication (ECPR)/classical photolithography based microscale metallization (CL) study the results reflects the fewer number of process steps and the lower electricity consumption needed by the ECPR to reach the functional unit. The difference in results is large enough to be able to draw conclusions, as the processes, having the highest electricity consumption within the system boundaries have been determined. Based on an earlier work, a straightforward method to include uncertainty for input life cycle inventory data is used to quantify the influence of realistic errors for input data in two microelectronic applications. The conclusion is that the ECPR technology is more electricity efficient than CL in producing one layer of copper on a silicon wafer having a diameter of 20.32 cm. Furthermore, the longer technical life of a cordless DECT phone is reflected in an electricity/CO2 comparison with a GSM phone, if office use is considered. Reasonable uncertainty intervals, used for the input life cycle inventory data for the studied DECT/GSM and ECPR/CL system, does affect the outcome of calculation of emission of CO2, but not to the degree that conclusions are not valid. Different uncertainty intervals and probability distributions could apply for different types of data and the interrelated input data dependencies should be investigated. Today there exist very few life cycle inventory (LCI) data with the range of uncertainty for input and output elements. It must be emphasized that the upcoming LCI databases should have standard deviation characterized LCI data just as the Swiss ecoinvent LCI database. More inventory parameters and probability distributions characteristic for microsystems could be included and error analysis should be applied to future life inventory methodology, especially for future packaging concepts such as system-in-a-package and system-on-a-chip comparisons.
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| 10. |
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