| 191. |
- Klein, Markus, et al.
(författare)
-
Dual-trap technique for reduction of low-frequency noise in force measuring optical tweezers
- 2007
-
Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 46:3, s. 405-412
-
Tidskriftsartikel (refereegranskat)abstract
- High-resolution long-time force measurements by optical tweezers are often limited by low- frequency (1/f) noise. A dual-trap technique is presented that can reduce such noise in the force signal. It incorporates a second trap (a reference trap) that probes the noise in the system and it is based upon the assumption that the low-frequency parts of the noise from the two traps are correlated. A subtraction of the low-frequency signal from the reference trap from the signal from the force measuring trap will therefore yield a net signal that is significantly less influenced by noise. It is shown that this dual-trap technique can reduce the noise in the force signal up to 60% depending on detection bandwidth.
|
|
| 192. |
|
|
| 193. |
- Krivchikov, Alexander I., et al.
(författare)
-
Thermal Conductivity of Triphenyl Phosphite's Liquid, Glassy, and Glacial States
- 2016
-
Ingår i: Journal of Physical Chemistry B. - : American Chemical Society (ACS). - 1520-6106 .- 1520-5207. ; 120:10, s. 2845-2853
-
Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity kappa and heat capacity per unit volume rho C-p of triphenyl phosphite (TPP) were measured under different pressure and temperature conditions, and with time during the sluggish liquid to glacial state transformation at temperatures about 15 K above the glass transition temperature. As the transformation slowly proceeds during several hours, rho C-p decreases monotonically from that of the liquid state to a value close to that of the vitrified state. Concurrently, kappa increases nonmonotonically with an intermediate local maximum followed by a minimum, before the final rise to a higher kappa. The properties of the ultimately formed glacial state depend on the thermal history, which implies that the state formed under these conditions is a heterogeneous mixture of nanocrystals and mainly amorphous-like solid, and that the relative amount and microstructure depend on the conditions of the transformation. The nonmonotonic changes in phonon propagation during the liquid to glacial transformation suggest microstructural changes which are consistent with a liquid-liquid transformation and sluggish growth of nanocrystals within amorphous-like solid domains. The isobaric thermal conductivity of the as-formed glacial state shows a reversible step increase, just prior to crystallization on heating, which deviates from the typical behavior of glasses, liquids, and crystals. An increase in pressure shifts the step to higher temperatures and suppresses crystallization, which reveals another reversible rise in kappa and C-p. These results show that increased molecular mobility in the glacial state increases and suggest reduced thermal resistance at boundaries or that the motions carry heat.
|
|
| 194. |
- Krivchikov, Alexander, et al.
(författare)
-
Thermal conductivity of solid triphenyl phosphite
- 2022
-
Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 27:23
-
Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity, κ, of solid triphenyl phosphite was measured by using the transient hot-wire method, and its temperature and pressure dependencies were analyzed to understand heat transfer processes in the solid polymorphic phases, as well as in the glass and the exotic glacial state. Phase transformations and the structural order of the phases are discussed, and a transitional pressure–temperature diagram of triphenyl phosphite is presented. The thermal conductivity of both the crystalline and disordered states is described within the theory of two-channel heat transfer by phonons and diffusons in dielectric solids. In the glass and glacial states, the weakly temperature-dependent (glass-like) κ is described well by the term associated with heat conduction of diffusons only, and it can be represented by an Arrhenius-type function. In the crystal phases, the strongly temperature-dependent (crystal-like) κ associated with heat transfer by phonons is weakened by significant heat transfer by diffusons, and the extent of the two contributions is reflected in the temperature dependence of κ. We find that the contribution of diffusons in the crystal phases depends on pressure in the same way as that in amorphous states, thus indicating that the same mechanism is responsible for this channel of heat transfer in crystals and amorphous states.
|
|
| 195. |
- Kvarven, Amanda, et al.
(författare)
-
The intuitive cooperation hypothesis revisited : a meta-analytic examination of effect size and between-study heterogeneity
- 2020
-
Ingår i: Journal of the Economic Science Association (JESA). - : Springer. - 2199-6776 .- 2199-6784. ; 6:1, s. 26-42
-
Tidskriftsartikel (refereegranskat)abstract
- The hypothesis that intuition promotes cooperation has attracted considerable attention. Although key results in this literature have failed to replicate in pre-registered studies, recent meta-analyses report an overall effect of intuition on cooperation. We address the question with a meta-analysis of 82 cooperation experiments, spanning four different types of intuition manipulations-time pressure, cognitive load, depletion, and induction-including 29,315 participants in total. We obtain a positive overall effect of intuition on cooperation, though substantially weaker than that reported in prior meta-analyses, and between studies the effect exhibits a high degree of systematic variation. We find that this overall effect depends exclusively on the inclusion of six experiments featuring emotion-induction manipulations, which prompt participants to rely on emotion over reason when making allocation decisions. Upon excluding from the total data set experiments featuring this class of manipulations, between-study variation in the meta-analysis is reduced substantially-and we observed no statistically discernable effect of intuition on cooperation. Overall, we fail to obtain compelling evidence for the intuitive cooperation hypothesis.
|
|
| 196. |
|
|
| 197. |
|
|
| 198. |
- Larsson, Roland, et al.
(författare)
-
Lubricant thermal conductivity and heat capacity under high pressure
- 2000
-
Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology. - : SAGE Publications. - 1350-6501 .- 2041-305X. ; 214:4, s. 337-342
-
Tidskriftsartikel (refereegranskat)abstract
- The thermal conductivity and the heat capacity per unit volume, ρcp, have been measured for a number of common lubricating oils. The oils tested were paraffinic and naphthenic mineral oils and a 50/50 blend of these. Poly-alpha-olefin, polyglycol, Santotrac, ester and rapeseed oils have also been tested. The measurements, using the transient hot-wire method, were carried out under isothermal conditions over a pressure range from atmospheric to 1.1 GPa and at two temperatures, 295 and 380 K (22 and 107 degrees C respectively).The temperature had only a marginal effect on thermal conductivity; however, the thermal conductivity was doubled as the pressure was increased to 1 GPa. The heat capacity per unit volume was influenced by both the pressure and the temperature. Some of the lubricants solidified as the pressure increased and the transition from a fluid to a solid state could be detected in the measurements of ρcp.The relationship between the thermodynamic properties and the pressure and temperature are described by two empirical equations. These equations can be used in thermal elastohydrodynamic analyses.
|
|
| 199. |
- Larsson, Regina, et al.
(författare)
-
Properties of electrolytes under pressure : PPG400 and PPG4000 complexed with LiCF3SO3
- 2003
-
Ingår i: Electrochimica Acta. - : Elsevier. - 0013-4686 .- 1873-3859. ; 48:23, s. 3481-3489
-
Tidskriftsartikel (refereegranskat)abstract
- High-pressure electrical conductivity measurements and differential thermal analysis have been carried out on poly(propylene glycol) (PPG) complexed with LiCF3SO3 (composition O:Li = 20:1) for pressures up to 1 GPa. The temperature and pressure dependence of the conductivity were analyzed in terms of the recently presented generalized Vogel equation as well as the well-known Vogel-Tamman-Fulcher equation, and the former provides an improved description of the data. The conductivity results show that the apparent activation volumes for the conduction process at room temperature and atmospheric pressure are 48 and 42 cm3 mol-1 for electrolyte based on PPG4000 (molecular weight = 4000) and PPG400, respectively. The temperature variation of the activation volume as well as the molecular weight dependence are described well within the free volume theory, which also provide a reasonable description of the pressure dependence. Differential thermal analysis was used to determine the pressure dependence of the glass transition temperature Tg for the electrolyte based on PPG400. The result for the initial slope dTg/dp = 140 K GPa-1 agrees well with that for the pure host PPG, but Tg is shifted up 6 K.
|
|
| 200. |
- Lefebure, Robert, et al.
(författare)
-
Impacts of elevated terrestrial nutrient loads and temperature on pelagic food-web efficiency and fish production
- 2013
-
Ingår i: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 19:5, s. 1358-1372
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Both temperature and terrestrial organic matter have strong impacts on aquatic food-web dynamics and production. Temperature affects vital rates of all organisms, and terrestrial organic matter can act both as an energy source for lower trophic levels, while simultaneously reducing light availability for autotrophic production. As climate change predictions for the Baltic Sea and elsewhere suggest increases in both terrestrial matter runoff and increases in temperature, we studied the effects on pelagic food-web dynamics and food-web efficiency in a plausible future scenario with respect to these abiotic variables in a large-scale mesocosm experiment. Total basal (phytoplankton plus bacterial) production was slightly reduced when only increasing temperatures, but was otherwise similar across all other treatments. Separate increases in nutrient loads and temperature decreased the ratio of autotrophic:heterotrophic production, but the combined treatment of elevated temperature and terrestrial nutrient loads increased both fish production and food-web efficiency. CDOM: Chl a ratios strongly indicated that terrestrial and not autotrophic carbon was the main energy source in these food webs and our results also showed that zooplankton biomass was positively correlated with increased bacterial production. Concomitantly, biomass of the dominant calanoid copepod Acartia sp. increased as an effect of increased temperature. As the combined effects of increased temperature and terrestrial organic nutrient loads were required to increase zooplankton abundance and fish production, conclusions about effects of climate change on food-web dynamics and fish production must be based on realistic combinations of several abiotic factors. Moreover, our results question established notions on the net inefficiency of heterotrophic carbon transfer to the top of the food web.
|
|
