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  • 1.
    Boden, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Simu, U.
    Margell, J.
    Lehto, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Materialvetenskap.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology. Materialvetenskap.
    Metallic high-pressure microfluidicpump with active valves2007Conference paper (Refereed)
  • 2.
    Bodén, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Simu, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A metallic micropump for high-pressure microfluidics2008In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 18, no 11, p. 115009-Article in journal (Refereed)
    Abstract [en]

    This paper presents one of the strongest mechanical sub-cm(3) sized micropumps for microfluidics. It consists of two active valves and one pumping chamber, each operated by a paraffin actuator that is driven by a low-voltage square pulse waveform. The pump is fabricated in a simple process using parylene-coated stainless steel stencils, paraffin and copper clad polyimide. When driving the pump at 0.07 Hz and 2.0 V (0.8 W) per actuator, it pumped water without leakage at a flow rate of 0.75 mu L min(-1) up to above 50 bar (5 MPa) back-pressure. The frequency dependence was evaluated and a maximum flow rate of 1 mu L min(-1) at 0.21 Hz and 1.8 V was observed. A thermomechanical FEM analysis, which was in good agreement with experiments at low frequencies, predicts the behaviour at higher frequencies.

  • 3.
    Bodén, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Simu, Urban
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Metallic high-pressure microfluidic pump2008In: MSW08, 2008, p. 29-Conference paper (Refereed)
  • 4.
    Bodén, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Lehto, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Margell, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    On-chip liquid storage and dispensing for lab-on-a-chip applications2008In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 18, no 7, p. 075036-Article in journal (Refereed)
    Abstract [en]

    This work presents novel components for on-chip storage and dispensing inside a lab-on-a-chip (LOC) for applications in immunoassay point-of-care testing (POCT), where incubation and washing steps are essential. It involves easy-to-use on-chip solutions for the sequential thermo-hydraulic actuation of liquids. The novel concept of combining the use of a rubber plug, both as a non-return valve cap and as a liquid injection interface of a sealed reservoir, allows simple filling of a sterilized cavity, as well as the storage and dispensing of reagent and washing buffer liquids. Segmenting the flow with air spacers enables effective rinsing and the use of small volumes of on-chip stored liquids. The chip uses low-resistance resistors as heaters in the paraffin actuator, providing the low-voltage actuation that is preferred for handheld battery driven instruments.

  • 5.
    Bodén, Roger
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Lehto, Marcus
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Margell, Joakim
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Towards a self-contained Lab on a Chip concept with sequential drive for point-of-care testingIn: Lab-on-a-chipArticle in journal (Other academic)
  • 6.
    Bodén, Roger
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Lehto, Marcus
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Thornell, Greger
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Hjort, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Schweitz, Jan-Åke
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    A Polymeric Paraffin Micropump with Active Valves for High-Pressure Microfluidics2005In: The 13th International Conference on Solid-State Sensors, Actuators and Microsystems, Seoul, Korea, 2005Conference paper (Refereed)
  • 7.
    Bodén, Roger
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Lehto, Marcus
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Thornell, Greger
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Hjort, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Schweitz, Jan-Åke
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    A polymeric paraffin actuated high-pressure micropump2005In: SenArticle in journal (Refereed)
  • 8.
    Boman, Mats
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry. oorganisk kemi.
    Schweitz, Jan-Åke
    Technology, Department of Materials Science. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Materials Chemistry, Inorganic Chemistry.
    Laser micromachining2001In: Invited talk, Micro- and Nanotechnologies LSU/CAMD Summer School 2001, Baton Rouge, LA, USA. - 2001, 2001Conference paper (Refereed)
  • 9.
    Klintberg, Lena
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Karlsson, M
    Stenmark, Lars
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Materials Science.
    A large stroke, high force paraffin phase transition actuator2002In: Sensors and Actuators A-Physical, ISSN 0924-4247, E-ISSN 1873-3069, Vol. 96, no 2-3, p. 189-195Article in journal (Refereed)
    Abstract [en]

    An actuator that uses the volume expansion related to the solid-to-liquid phase transition of paraffin wax has been fabricated and evaluated. The actuator consists of a ring-shaped paraffin cavity confined by two joint silicon diaphragms with rigid centers. When the paraffin is melted, the resulting hydrostatic pressure deflects the joined rigid centers in one direction only. The magnitude of the deflection is primarily a function of the geometrical relation between the two diaphragms, giving the opportunity to tailor the behavior of the actuator in a large range. Conventional IC-processing techniques have been used to fabricate a prototype with a width of 68 mm and a thickness of 825 μm. The prototype attained a maximum deflection of ca. 90 μm. Loaded with 3 N it still exhibits a deflection of ca. 75 μm. The device can be used as a thermal switch.

  • 10.
    Lehto, Marcus
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Bodén, Roger
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Hjort, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Schweitz, Jan-Åke
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Printed circuit board paraffin actuators for disposable microfluidic systems2004In: ACTUATOR, Bremen, Gemany, 2004Conference paper (Refereed)
  • 11.
    Lehto, Marcus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
    Bodén, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Simu, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Micro Structural Technology.
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    A polymeric paraffin microactuator2008In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 17, no 5, p. 1172-1177Article in journal (Refereed)
    Abstract [en]

    Paraffin wax is a promising material in microactuators not only because of its ability of producing large displacements and high forces at the same time but also because of the variety of manufacturing techniques available. In this paper, a simple actuator based on paraffin wax as the active material is fabricated and tested. Ultraviolet-curable epoxy is used in a technique combining simultaneous moulding and liquid-phase photopolymerization in a single-process step to build the stiff part of the actuator body. A heater is integrated in the paraffin reservoir, and a polyimide tape is used as the deflecting membrane. Thermornechanical analysis of the paraffin wax shows that it exhibits a volume expansion of 10%, including phase transitions and linear expansion. As for the actuator, a stroke of 90 mu m is obtained for the unloaded device, whereas 37 mu m is recorded with a 0.5-N contact load at a driving voltage of 0.71 V and a frequency of 1/32 Hz. The actuator can be used in microsystems, where both large strokes and forces are needed. The low-cost materials and low driving voltage also makes it suitable for disposable systems.

  • 12.
    Lehto, Marcus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Bodén, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Simu, Urban
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Rapid prototyping of a polymeric paraffin microactuator2008In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 17, no 5, p. 1172-1177Article in journal (Refereed)
    Abstract [en]

    Paraffin wax is a promising material in microactuators not only because of its ability of producing large displacements and high forces at the same time but also because of the variety of manufacturing techniques available. In this paper, a simple actuator based on paraffin wax as the active material is fabricated and tested. Ultraviolet-curable epoxy is used in a technique combining simultaneous moulding and liquid-phase photopolymerization in a single-process step to build the stiff part of the actuator body. A heater is integrated in the paraffin reservoir, and a polyimide tape is used as the deflecting membrane. Thermomechanical analysis of the paraffin wax shows that it exhibits a volume expansion of 10%, including phase transitions and linear expansion. As for the actuator, a stroke of 90 mum is obtained for the unloaded device, whereas 37 mum is recorded with a 0.5-N contact load at a driving voltage of 0.71 V and a frequency of 1/32 Hz. The actuator can be used in microsystems, where both large strokes and forces are needed. The low-cost materials and low driving voltage also makes it suitable for disposable systems.

  • 13.
    Lehto, Marcus
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Schweitz, Jan-Åke
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Hjort, Klas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Simu, Urban
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Bodén, Roger
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Thornell, Greger
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Engineering Sciences. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Physics, Department of Physics and Materials Science, Materials Science.
    Phase-change devices for on-chip drive and control of microfluidic systems2004In: 5th Micro Structure Workshop, Ystad, Sweden, 2004, p. 61-62.Conference paper (Other scientific)
  • 14.
    Lehto, Marcus
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Thornell, Greger
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Binary mixtures of n-alkanes for tunable thermohydraulic microactuators2007In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 16, no 3, p. 728-733Article in journal (Refereed)
    Abstract [en]

    The two objectives of this paper are related to the use of n-alkanes in actuators. The first objective is to study the thermomechanics of binary mixtures of dotriacontane and hexatriacontane to see if a quasi-stable thermal expansion can be obtained, and the second one is to find the correspondence between dilatometry [pressure, volume, and temperature (pVT) measurement] and differential scanning calorimetry (DSC). Results show that there is indeed a concentration-dependent plateau in the expansion curves and that the width and horizontal position of this can be adjusted. As compared with pure n-alkanes, the plateaus of the mixtures widen by a factor of 2-4, and as compared with pure hexatriacontane, they shift their low-end temperatures by 5 °C to 10 °C, in the 25% to 75% concentration range. The mixtures' plateaus (gathered around 0.06 cm3/g) are about 0.02 cm3/g below those of the pure n-alkanes. It is shown that DSC can be used for a prediction of the thermomechanical properties of the substances, provided that a pVT reference exists, and the fact that the melting point increases with the pressure that is experienced with the dilatometer is considered. The qualitative similarity between the expansion and enthalpy curves is remarkable. About 25% to 30% of the total volume expansion is attributed to the solid-to-solid phase transition; the rest is attributed to thermal expansion and melting.

  • 15.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dark Source Flux Cosmology: An Occam’s Razor UniverseManuscript (preprint) (Other academic)
    Abstract [en]

    A new model for the metric expansion of the universe is developed from basics. It is based on recent observational results and the model is established in the minimalist spirit of Occam’s razor. A detailed analysis shows that the principle of energy conservation simply does not hold in a universe undergoing spatially flat-metric accelerating expansion. Consequently, the non-inertial, accelerating expansion of the spatially flat universe is proposed to be driven by a non-conservative influx of new energy, in natural agreement with commonly accepted physics. (This source flux is fundamentally different from the one proposed in the Steady State Model.) A Big Bang beginning is predicted and the observed expansion features of the universe are readily explained, qualitatively as well as numerically. Dark energy is identified as the kinetic expansion energy of the universe; consequently its ‘exotic’ negative pressure in standard cosmology is replaced by more realistic positive pressure. A new, strong relationship between dark energy and other cosmic media is revealed. The theory yields singular and non-singular Big Bang solutions; the Planck unit system being closely linked to the non-singular primordial state of the universe. This new model is less restricted than standard cosmology and shows better predictive power.

  • 16.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Dark source flux, dark energy and the expansion of the flat universeManuscript (preprint) (Other academic)
    Abstract [en]

    Recent WMAC and Planck data confirm that the universe is spatially flat also in a General Relativity framework. This article aims at demonstrating that in the flat-metric, uniform universe approximation, a new set of initial assumptions – consistent with earlier and recent observations – results in a simple, rigorous expansion theory, free-standing from General Relativity and readily explaining the observed expansion features of the universe, both qualitatively and quantitatively. A Big Bang singularity and the existence of a non-zero ground level density of dark energy permeating all space and being a physical manifestation of the invariant ground state space, follows from the theory. The basic hypothesis is that the universe is inflated by a uniformly distributed source flux of dark energy – a dark source flux – generating the observed volume expansion. This source flux makes possible a concise mathematical formulation of the metric expansion in terms of one single variable (cosmic time) and two measurable universal constants. The model completely determines the evolution of the universe from Big Bang to eternity and provides a seamless connection between the early epoch of rapid inflation and our present epoch of slower but accelerating expansion. It features a transition from decelerating to accelerating expansion in an interval of time consistent with astrophysical observations. All expansion parameters – including total density and dark energy density – are derived and evaluated from merely two experimental input parameters: a measured Hubble constant and the age of the universe estimated from the age of the oldest known star. The numerical results are well in line with recent WMAP and Planck results, but in contrast to these do not rely on best-fit procedures. The model also reveals an intimate relation between the dark energy and the matter contents of the universe. The dark source flux defines a cosmological arrow of time and opens up a new and tangible physical perspective in the understanding of the evolution of the expanding universe.

  • 17.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Does the Planck unit system relate to a non-singular primordial state of the universe?Manuscript (preprint) (Other academic)
    Abstract [en]

    Recently, a new model for flat-metric expansion of the universe that eliminates several problems arising in the expansion theory of standard cosmology was presented. In the original version of this dark source flux (DSF) model, Big Bang is manifested by a mathematical singularity with infinite initial matter density and infinite initial expansion rate. However, an integration constant (a time shift) with extremely small value was for simplicity set equal to zero in this theory. A closer analysis reveals that if this constant is assigned a very small nonzero value, Big Bang will not have started from a mathematical singularity, but from a primordial state of extremely high, yet limited density and expansion rate. This primordial state constitutes a non-singular Planck epoch of extremely short duration. It turns out that all primordial state parameters assume values of the order of Planck units. Thus, the Planck unit system may have found an attractive physical significance: it relates to the primordial Planck state of the universe where the three fundamental theories of physics merge.

    There is a well known, puzzling ratio (of the order 10120) between ground state (‘vacuum’) density values  based on quantum field theory on one hand, and experimental values derived from ΛCDM (or DSF) on the other. This discrepancy has been called the worst theoretical prediction in the history of science. The present article offers a possible explanation to this issue.

  • 18.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Microsystems Technology.
    Pressure in dark source flux cosmologyManuscript (preprint) (Other academic)
    Abstract [en]

    A cosmological pressure concept is defined from virial equations for open systems undergoing Hubble expansion. A uniform dark source flux model is assumed, comprising non-relativistic baryonic and dark matter (‘dust’); relativistic radiation; and dark energy. The pressures thus derived are compared with corresponding pressures derived from the Friedmann equation in standard cosmology. The pressures are found to agree for non-relativistic matter and relativistic radiation, but differ for dark energy. The ‘exotic’ negative pressure of dark energy in standard cosmology is replaced by a more down-to-earth positive pressure in the present theory. The reason for this deviation is that the local energy conservation criterion, which is built into the field equation in general relativity, is replaced by a compelling consequence of Hubble’s law: the criterion for balanced expansion. In the choice between questionable energy conservation in an accelerating system on one hand, and the experimentally verified Hubble’s law on the other, the latter is chosen in the present analysis.

  • 19.
    Thornell, Greger
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. Materialvetenskap.
    Ericson, Fredrik
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. Materialvetenskap.
    Hedlund, Christer
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. Fasta tillståndets elektronik.
    Ohrmalm, J
    Schweitz, Jan-Åke
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Technology, Department of Materials Science. Physics, Department of Physics and Materials Science, Materials Science. Department of Engineering Sciences, Electronics. Materialvetenskap.
    Portnoff, G
    Residual stress in sputtered gold films on quartz measured by the cantilever beam deflection technique1999In: IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL, ISSN 0885-3010, Vol. 46, no 4, p. 981-992Article in journal (Refereed)
    Abstract [en]

    With resonator applications in mind, the residual stress in sputtered gold electrodes on quartz has been investigated with respect to various deposition rates (2, 10, and 50 Angstrom/s), pressures (1.0 and 3.0 . 10(-3) mbar), deposition temperatures (80 d

  • 20.
    Valizadeh, Sima
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
    Abid, Muhammed
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
    Romano-Rodriguez, A
    Hjort, Klas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Materialvetenskap.
    Schweitz, Jan-Åke
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Materialvetenskap.
    Electrical contacting of individual electrodeposited Au Nanowire by Focused Ion Beam techniques2006In: Nanotechnology, p. 1134-1139Article in journal (Refereed)
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    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Experimental Physics.
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    Nanoscale Electrical Transport Measurements by Focused Ion Beam2006Conference paper (Refereed)
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    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. Fasta tillståndets fysik.
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    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Materials Science. Materialvetenskap.
    Nanoscale Electrical Transport Measurements by Focused Ion Beam2006In: SPIE NEWS ROOMArticle in journal (Refereed)
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