A Listing of Current Books

Att bygga energieffektiva bostäder blir idag allt viktigare. Grunden till detta arbete ligger i vårt intresse för energismart byggande och företagens nyfikenhet över huruvida de lyckats bygga energismart. Syftet med denna undersökning är att jämföra energiförbrukning för två principiella tillvägagångssätt att bygga flerbostadshus, som passiv- eller lågenergihus. De frågor som valts att behandla är: Vad krävs för att ett hus ska klassas som ett passivhus respektive lågenergihus år 2009? Klarar respektive konstruktion målet för energiförbrukning? Vilka faktorer påverkar skillnaden i den specifika energiförbrukningen? Vilken typ av koncept rekommenderas? Utifrån en teoretisk referensram inom området och tillhandahållet material, såsom ritningar och uppgifter om energiförbrukning, har en jämförelse mellan dessa två olika konstruktioner gjorts. Studien har riktat in sig på att studera parametrar som specifik energiförbrukning per Atemp och bidragande faktorer till en mer eller mindre lyckad energiförbrukning

Comment on: "Estimating the Hartree-Fock limit from finite basis set calculations" [Jensen F (2005) Theor Chem Acc 113:267]

We demonstrate that a minor modification of the extrapolation proposed by Jensen [(2005): Theor Chem Acc 113:267] yields very reliable estimates of the Hartree-Fock limit in conjunction with correlation consistent basis sets. Specifically, a two-point extrapolation of the form $E_{HF,L}=E_{HF,\infty}+A(L+1)\exp(-9\sqrt{L})$ yields HF limits $E_{HF,\infty}$ with an RMS error of 0.1 millihartree using aug-cc-pVQZ and aug-cc-pV5Z basis sets, and of 0.01 millihartree using aug-cc-pV5Z and aug-cc-pV6Z basis sets.Comment: Theoretical Chemistry Accounts, in pres

Heats of formation of perchloric acid, HClO4_4, and perchloric anhydride, Cl2_2O7_7. Probing the limits of W1 and W2 theory

The heats of formation of HClO$_4$ and Cl$_2$O$_7$ have been determined to chemical accuracy for the first time by means of W1 and W2 theory. These molecules exhibit particularly severe degrees of inner polarization, and as such obtaining a basis-set limit SCF component to the total atomization energy becomes a challenge. (Adding high-exponent $d$ functions to a standard $spd$ basis set has an effect on the order of 100 kcal/mol for Cl$_2$O$_7$.) Wilson's aug-cc-pV(n+d)Z basis sets represent a dramatic improvement over the standard aug-cc-pVnZ basis sets, while the aug-cc-pVnZ+2d1f sequence converges still more rapidly. Jensen's polarization consistent basis sets still require additional high-exponent $d$ functions: for smooth convergence we suggest the \{aug-pc1+3d,aug-pc2+2d,aug-pc3+d,aug-pc4\} sequence. The role of the tight $d$ functions is shown to be an improved description of the Cl (3d) Rydberg orbital, enhancing its ability to receive back-bonding from the oxygen lone pairs. In problematic cases like this (or indeed in general), a single SCF/aug-cc-pV6Z+2d1f calculation may be preferable over empirically motivated extrapolations. Our best estimate heats of formation are $\Delta H^\circ_{f,298}[$HClO$_4$(g)$]=-0.6\pm$1 kcal/mol and $\Delta H^\circ_{f,298}[$Cl$_2$O$_7$(g)$]=65.9\pm$2 kcal/mol, the largest source of uncertainty being our inability to account for post-CCSD(T) correlation effects. While G2 and G3 theory have fairly large errors, G3X theory reproduces both values to within 2 kcal/mol.Comment: J. Mol. Struct. (THEOCHEM), in press (WATOC'05 special issue

Life Cycle Savings, Bequest, and the Diminishing Impact of Scale on Growth

There appears to be ample evidence that the size of population acted as a stimulus to growth in historical times; scale mattered. In the post World War II era, however, there is little evidence of such scale effects on growth. Where did the scale effect go? The present paper shows that the savings motive critically affects the size and sign of scale effects in standard endogenous growth models. If the bequest motive dominates, the scale effect is positive. If the life cycle motive dominates, the scale effect is ambiguous and may be negative. A declining importance of bequest in capital accumulation could therefore be one reason why scale seems to matter less today than in historical times.overlapping generations; endogenous growth; scale effects

Økologiske kødprodukter med urter og bær

Danske urter og bær skal både give nye smagsoplevelser og en konserverende effekt, så holdbarheden af økologiske kødprodukter forbedres

Planteudtræk i stedet for antibiotika, zink og kobber til små-grise ved fravænning

Præsentation af MAFFRA projektet på ICROFS statusmøde 201

Assessment of Various Density Functionals and Basis Sets for the Calculation of Molecular Anharmonic Force Fields

In a previous contribution (Mol. Phys. {\bf 103}, xxxx, 2005), we established the suitability of density functional theory (DFT) for the calculation of molecular anharmonic force fields. In the present work, we have assessed a wide variety of basis sets and exchange-correlation functionals for harmonic and fundamental frequencies, equilibrium and ground-state rotational constants, and thermodynamic functions beyond the RRHO (rigid rotor-harmonic oscillator) approximation. The fairly good performance of double-zeta plus polarization basis sets for frequencies results from an error compensation between basis set incompleteness and the intrinsic error of exchange-correlation functionals. Triple-zeta plus polarization basis sets are recommended, with an additional high-exponent $d$ function on second-row atoms. All conventional hybrid GGA functionals perform about equally well: high-exchange hybrid GGA and meta-GGA functionals designed for kinetics yield poor results, with the exception of of the very recently developed BMK functional which takes a middle position along with the HCTH/407 (second generation GGA) and TPSS (meta-GGA) functionals. MP2 performs similarly to these functionals but is inferior to hybrid GGAs such as B3LYP and B97-1.Comment: Int. J. Quantum Chem., in press (special issue on vibrational spectroscopies

BerryMeat: Ny smag og bedre holdbarhed af økologiske kødprodukter

Short introcduction to the berryMeat project as presented on the "Food Festival" in Aarhus, Denmark 7. september 201

Pressure Calculation in Polar and Charged Systems using Ewald Summation: Results for the Extended Simple Point Charge Model of Water

Ewald summation and physically equivalent methods such as particle-mesh Ewald, kubic-harmonic expansions, or Lekner sums are commonly used to calculate long-range electrostatic interactions in computer simulations of polar and charged substances. The calculation of pressures in such systems is investigated. We find that the virial and thermodynamic pressures differ because of the explicit volume dependence of the effective, resummed Ewald potential. The thermodynamic pressure, obtained from the volume derivative of the Helmholtz free energy, can be expressed easily for both ionic and rigid molecular systems. For a system of rigid molecules, the electrostatic energy and the forces at the atom positions are required, both of which are readily available in molecular dynamics codes. We then calculate the virial and thermodynamic pressures for the extended simple point charge (SPC/E) water model at standard conditions. We find that the thermodynamic pressure exhibits considerably less system size dependence than the virial pressure. From an analysis of the cross correlation between the virial and thermodynamic pressure, we conclude that the thermodynamic pressure should be used to drive volume fluctuations in constant-pressure simulations.Comment: RevTeX, 19 pages, 2 EPS figures; in press: Journal of Chemical Physics, 15-August-199