4,592 research outputs found
The Model Business Corporation Act Financial Provisions: A Historical Snapshot
Som följd av den pÄgÄende urbaniseringen har de naturliga förutsÀttningarna för regn och smÀltvattnet att infiltrera i marken och ÄtergÄ till sitt kretslopp pÄ naturlig vÀg försvunnit i stÀderna. I Stockholm leds ungefÀr hÀlften av dagvattnet via VA-nÀtet direkt och orenat till reningsverken. Dagvattenflödet varierar kraftigt vilket orsakar toppar som överbelastar VAnÀtet och Àr svÄra för reningsverken att hantera. IstÀllet för att ledas ut i VA-nÀtet ska dagvatten strÀvas efter att hanteras lokalt. Arbetet lÀgger fokus pÄ dagvattenhanteringen för takparken pÄ ett nybyggnadsprojekt i Stockholm, projektet PARK 1. Projektet ritas av White arkitekter och ska certifieras enligt BREEAM och dÀr nÄ den högsta klassningen Outstanding. HÄllbar anvÀndning av mark och vatten Àr dÀrför en av de viktiga frÄgorna i detta projekt. Syftet med arbetet Àr att omarbeta ett gestaltningsförslag av PARK1Žs takpark samt att presentera lösningar för dess dagvattenhantering. Detta utförs med hÀnsyn till framtida klimatförÀndringar och byggnadens vattenkretslopp samt samordning och tillgÀnglighet. Arbetet utförs frÀmst genom litteraturstudier, men har ocksÄ kompletterats genom samtal, diskussioner och studiebesök. AutoCAD, SketchUp och Photoshop anvÀnds för att illustera den planerade parken samt dess vÀxter, funktioner och konstruktionslösningar. Dimensioneringen av brunnar och stammar görs med hÀnsyn till 100-Ärsregn för att klara framtida klimatförÀndringar. Med hjÀlp av nederbördsstatistik berÀknas sannolik nederbörd för parken, denna mÀngd motsvara det dagvatten som ska hanteras lokalt. Avrinningsytan gÄr frÄn att vara en parkeringsplats dÀr allt dagvatten belastar VA-nÀtet till att bli en takpark dÀr dagvattnet utnyttjas till bevattning och 25 procent av byggnadens WCspolning. Dagvattnet blir direkt pÄ platsen omvandlat till spillvatten och som följd blir tillförseln till vatten- och avloppsnÀtet frÄn byggnaden jÀmn och stabil och fÀrskvattenförbrukningen sÀnks.As a result of ongoing urbanization, natural conditions for rain and meltwater to infiltrate in the ground and regress to the natural water cycle have disappeared in cities. About half of the stormwater in Stockholm is transported through the municipal water sewerage system directly to sewage treatment works. The flow of stormwater varies vigorously, causing flow peaks that overburden the system and treatment works. The aim should be to handle and use the stormwater locally instead of releasing it to the system. The focus of this bachelor thesis is how stormwater from a soon to be built construction project in Stockholm can be handled. The project, PARK 1, is designed by the architectural firm White Arkitekter and is set to be BREEAM certified and to reach the classification outstanding. Therefore, sustainable use of land and water resources is one of the key matters in the project. The purpose of the study is to rework a existing design proposal for the rooftop garden planed on PARK1 and present solutions for stormwater usage. Consideration must be taken to future climate changes, coordination among disciplines and accessibility. The work was conducted mainly through literature studies and complemented by discussions and site visits to reference projects. AutoCAD, SketchUp and Photoshop were used to illustrate plans and details of the park proposal with its plantations, activities and technical solutions. Estimations of the quantity of roof outlets and dimensions of vertical downpipes were made for 100-year rain conditions. Through quantitative analysis of precipitation statistics the expected precipitation were calculated. Which after runoff covers the irrigation needs of the park and 25 percent of the water needed for flushing of the buildings WC:s. The runoff surface is altered from being a parking lot where all stormwater ends up in the municipal water sewerage, to a rooftop garden where all of the stormwater is handled locally. This allows stormwater to be transformed into wastewater on sight, thereby contributing to a steady flow in sewer pipes in addition to help lower the buildings fresh water consumption
A Matter of Good Form: The (Downsized) Hague Judgments Convention and Conditions of Formal Validity for the Enforcement of Forum Selection Agreements
Can the Hague Judgments Convention be saved through radical downsizing? It has been more than ten years since the Hague Conference on Private International Law (Hague Conference) first officially began exploring the possibility of drafting a global convention on jurisdiction and the enforcement of foreign judgments in civil and commercial matters. (1) It has been more than four years since the Conference presented its preliminary draft convention, (2) itself modeled largely on the European Community\u27s 1968 Brussels Convention on Jurisdiction and the Enforcement of Judgments in Civil and Commercial Matters (Brussels I). (3) However, this preliminary draft convention was rejected as unacceptable by the American delegation, (4) and a subsequent interim text (5) indicated that Hague Conference delegates remained far from consensus on a wide range of issues. (6
Poisson and Porter-Thomas Fluctuations in off-Yrast Rotational Transitions
Fluctuations associated with stretched E2 transitions from high spin levels
in nuclei around Yb are investigated by a cranked shell model extended
to include residual two-body interactions. It is found that the gamma-ray
energies behave like random variables and the energy spectra show the Poisson
fluctuation, in the cranked mean field model without the residual interaction.
With two-body residual interaction included, discrete transition pattern with
unmixed rotational bands is still valid up to around 600 keV above yrast, in
good agreement with experiments. At higher excitation energy, a gradual onset
of rotational damping emerges. At 1.8 MeV above yrast, complete damping is
observed with GOE type fluctuations for both energy levels and transition
strengths(Porter-Thomas fluctuations).Comment: 21 pages, phyzzx, YITP/K-99
Non-Abelian generalization of off-diagonal geometric phases
If a quantum system evolves in a noncyclic fashion the corresponding
geometric phase or holonomy may not be fully defined. Off-diagonal geometric
phases have been developed to deal with such cases. Here, we generalize these
phases to the non-Abelian case, by introducing off-diagonal holonomies that
involve evolution of more than one subspace of the underlying Hilbert space.
Physical realizations of the off-diagonal holonomies in adiabatic evolution and
interferometry are put forward.Comment: Additional material, journal reference adde
A variational polaron self-interaction corrected total-energy functional for charge excitations in wide-band gap insulators
We conduct a detailed investigation of the polaron self-interaction (pSI)
error in standard approximations to the exchange-correlation (XC) functional
within density-functional theory (DFT). The pSI leads to delocalization error
in the polaron wave function and energy, as calculated from the Kohn-Sham (KS)
potential in the native charge state of the polaron. This constitutes the
origin of the systematic failure of DFT to describe polaron formation in band
insulators. It is shown that the delocalization error in these systems is,
however, largely absent in the KS potential of the closed-shell neutral charge
state. This leads to a modification of the DFT total-energy functional that
corrects the pSI in the XC functional. The resulting pSIC-DFT method
constitutes an accurate parameter-free {\it ab initio} methodology for
calculating polaron properties in insulators at a computational cost that is
orders of magnitude smaller than hybrid XC functionals. Unlike approaches that
rely on parametrized localized potentials such as DFT+, the pSIC-DFT method
properly captures both site and bond-centered polaron configurations. This is
demonstrated by studying formation and migration of self-trapped holes in
alkali halides (bond-centered) as well as self-trapped electrons in an
elpasolite compound (site-centered). The pSIC-DFT approach consistently
reproduces the results obtained by hybrid XC functionals parametrized by
DFT+ calculations. Finally, we generalize the pSIC approach to hybrid
functionals, and show that in stark contrast to conventional hybrid
calculations of polaron energies, the pSIC-hybrid method is insensitive to the
parametrization of the hybrid XC functional. On this basis, we further
rationalize the success of the pSIC-DFT approach.Comment: 10 pages, 7 figure
Quasi-particle spectra, absorption spectra, and excitonic properties of sodium iodide and strontium iodide from many-body perturbation theory
We investigate the basic quantum mechanical processes behind non-proportional
response of scintillators to incident radiation responsible for reduced
resolution. For this purpose, we conduct a comparative first principles study
of quasiparticle spectra on the basis of the approximation as well as
absorption spectra and excitonic properties by solving the Bethe-Salpeter
equation for two important systems, NaI and SrI. The former is a standard
scintillator material with well-documented non-proportionality while the latter
has recently been found to exhibit a very proportional response. We predict
band gaps for NaI and SrI of 5.5 and 5.2 eV, respectively, in good
agreement with experiment. Furthermore, we obtain binding energies for the
groundstate excitons of 216 meV for NaI and 19525 meV for SrI. We
analyze the degree of exciton anisotropy and spatial extent by means of a
coarse-grained electron-hole pair-correlation function. Thereby, it is shown
that the excitons in NaI differ strongly from those in SrI in terms of
structure and symmetry, even if their binding energies are similar.
Furthermore, we show that quite unexpectedly the spatial extents of the highly
anisotropic low-energy excitons in SrI in fact exceed those in NaI by a
factor of two to three in terms of the full width at half maxima of the
electron-hole pair-correlation function.Comment: 10 pages, 9 figure
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