1,723,797 research outputs found
Phase diagram measurements by Heat-flux DSC and thermodynamic calculations of the mixture of the Esters Ethyl undecanoate (C13H26O2) and Ethyl tridecanoate (C15H30O2)
No full textIn this report a phase diagram is determined by heat flux DSC of the binary mixture Ethyl undecanoate and Ethyl tridecanoate. Our hypothesis for equilibrium phase behaviour is that the components Ethyl undecanoate and Ethyl tridecanoate do have the same crystal form and they have restricted miscibility in that form. However, the results of the DSC measurements are complex and are not unambiguous. We determined a simple phase diagram and calculated it with the program Winifit. The calculated phase diagram with the program shows good similarity with the one obtained by the experiments. The excess Gibbs energy parameters of the solid state are determined with Winifit, being A = 5000 J.mol-1 and B = 0,1. The mole fraction of the critical point XC is calculated as XC =0,43. The critical temperature C T at XC =0,43 is also calculated, being C T = 307,2 K. For better understanding the crystal structures have to be examined in greater detail. On the left-hand side and on the right-hand side of the phase diagram they have to be the same
The origin of the ring current in the all-metal aromatic, Al4 2-
No full textApparent contradictions between ipsocentric, Nucleus-Independent Chemical Shift (NICS) and Gauge-Including Magnetically Induces Current (GIMIC) evaluations of ring current aromaticity in Al4 2- are resolved in favour of the descripion of this all-metal system as sigma aromatic on the magnetic criterion
Kijken naar colloïdale knikkers
No full textHarde bollen zijn de ‘fruitvliegjes’ van de statistische mechanica omdat ze vaak als basis gebruikt worden om meer ingewikkelde systemen te bestuderen [1]. Colloïden bieden unieke mogelijkheden om deze ‘fruitvliegjes’ experimenteel te bestuderen. Zo is het mogelijk om langs chemische weg de eigenschappen van colloïden naar wens aan te passen. Ook de typische colloïdale tijd- en lengteschalen zijn gemakkelijk toegankelijk met bijvoorbeeld optische microscopie. Dit artikel laat zien hoe deze kenmerkende combinatie van chemie, tijd- en lengteschalen het mogelijk maakt om direct de vrije energie te meten en het kristal-vloeistofgrensvlak van colloïdale harde bollen letterlijk in beeld te brengen
Material mechanics: an angle on sticky films
No full textThe interplay of various mechanical forces leads to characteristic shapes of torn adhesive films. Analysis of these shapes provides potential for new approaches to material characterization
Coupled valence bond theory
No full textIn this Letter, the formulation and implementation of a parallel response property code for non-orthogonal, valence bond wave-functions are described. Test calculations on benzene and cyclobutadiene show that the polarisability and magnetisability tensors obtained using valence bond theory are comparable to those obtained at the full p-CASSCF level of theory. The properties are a weighted average of those of its individual resonance structures. Resonance has no relevance for the polarisability and magnetisability
Comment on "Rachel Oliver's article on religion and environment"
No full textI enjoyed reading Rachel Oliver's article on religion and environment. These differences (both between and within religions) in how people see the relation between mankind, nature and God are quite interesting indeed
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