Defects of new-build dwellings constructed to building regulations and to ‘The Code for Sustainable Homes’

Fulltext in: http://www.arcom.ac.uk/-docs/proceedings/ar2013-1015-1025_Pan_Thomas.pdfDefect is an important aspect to address for enhancing quality of homes. However, there is little research into defects of new-build homes in the UK constructed to the 'Code for Sustainable Homes' which has been introduced to the UK building industry since 2007 as an environmental assessment tool. The aim of this paper is to contribute to knowledge of the defect profile of new homes regarding the defect number, type, location, severity and responsible trades. The research was carried out through analysing defect records for 327 homes in the UK constructed to the Code in comparison with to Building Regulations. In total 3209 defects were identified, with the mean average of 9.8 defects per home. Despite some extreme cases 91.4% of the dwellings studied were reported of 20 or less defects each. It is concluded that the defect profile of UK new-build homes since 2007 has improved in number, diversity and severity of defects. Nevertheless, kitchens and bathrooms remained as two most defective areas, with plumbers and painters/decorators being most often tasked for rectifications. With the evidence presented no clear relationship was observed between the defect profile of the homes and their performance standards or build methods adopted

Current Path Properties of the Transport Anisotropy at Filling Factor 9/2

To establish the presence and orientation of the proposed striped phase in ultra-high mobility 2D electron systems at filling factor 9/2, current path transport properties are determined by varying the separation and allignment of current and voltage contacts. Contacts alligned orthogonal to the proposed intrinsic striped phase produce voltages consistent with current spreading along the stripes; current driven along the proposed stripe direction results in voltages consistent with channeling along the stripes. Direct comparison is made to current spreading/channeling properties of artificially induced 1D charge modulated systems, which indicates the 9/2 direction.Comment: 10 pages, 4 figure

Piezoelectric mechanism of orientation of stripe structures in two-dimensional electron systems

A piezoelectric mechanism of orientation of stripes in two-dimensional quantum Hall systems in GaAs heterostructures is considered. The anisotropy of the elastic moduli and the boundary of the sample are taken into account. It is found that in the average the stripes line up with the [110] axis. In double layer systems the wave vector of the stripe structure rotates from the [110] to [100] axis if the period of density modulation becomes large than the interlayer distance. From the experimental point of view it means that in double layer systems anisotropic part of resistivity changes its sign under variation of the external magnetic field.Comment: 8 page

The fabrication of reproducible superconducting scanning tunneling microscope tips

Superconducting scanning tunneling microscope tips have been fabricated with a high degree of reproducibility. The fabrication process relies on sequential deposition of superconducting Pb and a proximity-coupled Ag capping layer onto a Pt/Ir tip. The tips were characterized by tunneling into both normal-metal and superconducting films. The simplicity of the fabrication process, along with the stability and reproducibility of the tips, clear the way for tunneling studies with a well-characterized, scannable superconducting electrode.Comment: 4 pages, 3 figures, REVTeX. Submitted to Rev. Sci. Instru

Integer quantum Hall effect on a six valley hydrogen-passivated silicon (111) surface

We report magneto-transport studies of a two-dimensional electron system formed in an inversion layer at the interface between a hydrogen-passivated Si(111) surface and vacuum. Measurements in the integer quantum Hall regime demonstrate the expected sixfold valley degeneracy for these surfaces is broken, resulting in an unequal occupation of the six valleys and anisotropy in the resistance. We hypothesize the misorientation of Si surface breaks the valley states into three unequally spaced pairs, but the observation of odd filling factors, is difficult to reconcile with non-interacting electron theory.Comment: 4 pages, 4 figures, to appear in Physical Review Letter

Dynamic Spin-Polarized Resonant Tunneling in Magnetic Tunnel Junctions

Precisely engineered tunnel junctions exhibit a long sought effect that occurs when the energy of the electron is comparable to the potential energy of the tunneling barrier. The resistance of metal-insulator-metal tunnel junctions oscillates with an applied voltage when electrons that tunnel directly into the barrier's conduction band interfere upon reflection at the classical turning points: the insulator-metal interface, and the dynamic point where the incident electron energy equals the potential barrier inside the insulator. A model of tunneling between free electron bands using the exact solution of the Schroedinger equation for a trapezoidal tunnel barrier qualitatively agrees with experiment.Comment: 4pgs, 3 fig

New mechanism for the enhancement of sdsd dominance in interacting boson models

We introduce an exactly solvable model for interacting bosons that extend up to high spin and interact through a repulsive pairing force. The model exhibits a phase transition to a state with almost complete $sd$ dominance. The repulsive pairing interaction that underlies the model has a natural microscopic origin in the Pauli exclusion principle between contituent nucleons. As such, repulsive pairing between bosons seems to provide a new mechanism for the enhancement of $sd$ dominance, giving further support for the validity of the $sd$ Interacting Boson Model.Comment: 4 pages, 2 figure

Density Induced Interchange of Anisotropy Axes at Half-Filled High Landau Levels

We observe density induced 90$^{\circ}$ rotations of the anisotropy axes in transport measurements at half-filled high Landau levels in the two dimensional electron system, where stripe states are proposed ($\nu$=9/2, 11/2, etc). Using a field effect transistor, we find the transition density to be $2.9\times10^{11}$cm$^{-2}$ at $\nu$=9/2. Hysteresis is observed in the vicinity of the transition. We construct a phase boundary in the filling factor-magnetic field plane in the regime $4.4<\nu<4.6$. An in-plane magnetic field applied along either anisotropy axis always stabilizes the low density orientation of the stripes.Comment: 1 revtex file, 3 eps figure

Multilevel semantic analysis and problem-solving in the flight domain

A computer based cockpit system which is capable of assisting the pilot in such important tasks as monitoring, diagnosis, and trend analysis was developed. The system is properly organized and is endowed with a knowledge base so that it enhances the pilot's control over the aircraft while simultaneously reducing his workload