Home Energy Ratings and Building Performance

This paper provides an overview of the Home Energy Rating System (HERS). A short summary of the origination and history of the HERS system will lead to a more detailed description of the inspection and testing protocol. The HERS rating provides an accepted method to determine home efficiency based on standards developed and overseen by the Residential Energy Services Network (RESNET), a not-for-profit corporation. The paper will discuss the effect of various building systems and effects of local climate as they affect the rating score of a proposed or completed structure. The rating is used to determine the most cost effective mechanical systems, building envelope design including window and door types, effect of various roofing materials and radiant barriers. The paper will conclude by comparing specifics of an actual report to the construction characteristics of a home as they relate to the HERS Rating and the result

The cerebral and systemic kinetics of thiopentone and propofol in halothane anaesthetized sheep

Publisher's copy made available with the permission of the publisher © Australian Society of AnaesthetistsThe cerebral and systemic kinetics of intravenous thiopentone (250 mg over 2 minutes, n=5) and propofol (100 mg over 2 minutes, n=6) were determined in sheep anaesthetized with halothane (2.0%) and mechanically ventilated to an end-expired carbon dioxide tension of 40 mmHg. The sheep were previously instrumented with arterial and sagittal sinus (effluent from the brain) blood sampling catheters. Systemic kinetics were inferred from the time-course of the arterial blood concentrations, and cerebral kinetics from the time-course of the arterio-sagittal sinus concentration difference across the brain. Under halothane anaesthesia, the peak arterial concentrations of each drug occurred at the end of the two-minute infusion, and was 42.3 mg/l and 12.3 mg/l for thiopentone and propofol, respectively. Propofol had a significantly larger systemic clearance (3.19 l/min) than thiopentone (0.99 l/min). The brain concentrations of propofol equilibrated more slowly with the arterial concentrations than those of thiopentone. The extraction ratio across the brain near the end of the infusions (1.5 min) were 0.85 and 0.46 respectively. These data were also compared to analogous previously published data for initially conscious sheep. The systemic kinetics of thiopentone were little affected by halothane anaesthesia. For propofol, halothane anaesthesia was associated with a statistically significant reduction in clearance (50% of awake), a slower initial half-life (247% of awake), and the emergence of a second slower half-life in some sheep. The cerebral kinetics of both drugs were subtly altered by halothane anaesthesia.R. N. Upton, G. L. Ludbrook, C. Granthttp://www.aaic.net.au/Article.asp?D=200024

The Bi-Hamiltonian Structure of the Short Pulse Equation

We prove the integrability of the short pulse equation derived recently by Sch\"afer and Wayne from a hamiltonian point of view. We give its bi-hamiltonian structure and show how the recursion operator defined by the hamiltonian operators is connected with the one obtained by Sakovich and Sakovich. An alternative zero-curvature formulation is also given.Comment: Latex file, 7 pages, to appear in Physics Letter

Limitation of finite element analysis of poroelastic behavior of biological tissues undergoing rapid loading

The finite element method is used in biomechanics to provide numerical solutions to simulations of structures having complex geometry and spatially differing material properties. Time-varying load deformation behaviors can result from solid viscoelasticity as well as viscous fluid flow through porous materials. Finite element poroelastic analysis of rapidly loaded slow-draining materials may be ill-conditioned, but this problem is not widely known in the biomechanics field. It appears as instabilities in the calculation of interstitial fluid pressures, especially near boundaries and between different materials. Accurate solutions can require impractical compromises between mesh size and time steps. This article investigates the constraints imposed by this problem on tissues representative of the intervertebral disc, subjected to moderate physiological rates of deformation. Two test cylindrical structures were found to require over 10(4) linear displacement-constant pressure elements to avoid serious oscillations in calculated fluid pressure. Fewer Taylor–Hood (quadratic displacement–linear pressure elements) were required, but with complementary increases in computational costs. The Vermeer–Verruijt criterion for 1D mesh size provided guidelines for 3D mesh sizes for given time steps. Pressure instabilities may impose limitations on the use of the finite element method for simulating fluid transport behaviors of biological soft tissues at moderately rapid physiological loading rates

Meissner response of anisotropic superconductors

The response field of a half-space anisotropic superconductor is evaluated for an arbitrary weak external field source. Example sources of a point magnetic moment and a circular current are considered in detail. For the penetration depth $\lambda \ll L$ with $L$ being any other relevant distance (the source size, or the distance between the source and the superconductor), the major contribution to the response is the $\lambda$ independent field of the source image. It is shown that the absolute value of $\lambda$ cannot be extracted from the response field with a better accuracy than that for the source position. Similar problems are considered for thin films.Comment: 8 pages, 0 figures. 7 pages: section removed, refs. adde

Existence and stability of viscoelastic shock profiles

We investigate existence and stability of viscoelastic shock profiles for a class of planar models including the incompressible shear case studied by Antman and Malek-Madani. We establish that the resulting equations fall into the class of symmetrizable hyperbolic--parabolic systems, hence spectral stability implies linearized and nonlinear stability with sharp rates of decay. The new contributions are treatment of the compressible case, formulation of a rigorous nonlinear stability theory, including verification of stability of small-amplitude Lax shocks, and the systematic incorporation in our investigations of numerical Evans function computations determining stability of large-amplitude and or nonclassical type shock profiles.Comment: 43 pages, 12 figure

On post-Lie algebras, Lie--Butcher series and moving frames

Pre-Lie (or Vinberg) algebras arise from flat and torsion-free connections on differential manifolds. They have been studied extensively in recent years, both from algebraic operadic points of view and through numerous applications in numerical analysis, control theory, stochastic differential equations and renormalization. Butcher series are formal power series founded on pre-Lie algebras, used in numerical analysis to study geometric properties of flows on euclidean spaces. Motivated by the analysis of flows on manifolds and homogeneous spaces, we investigate algebras arising from flat connections with constant torsion, leading to the definition of post-Lie algebras, a generalization of pre-Lie algebras. Whereas pre-Lie algebras are intimately associated with euclidean geometry, post-Lie algebras occur naturally in the differential geometry of homogeneous spaces, and are also closely related to Cartan's method of moving frames. Lie--Butcher series combine Butcher series with Lie series and are used to analyze flows on manifolds. In this paper we show that Lie--Butcher series are founded on post-Lie algebras. The functorial relations between post-Lie algebras and their enveloping algebras, called D-algebras, are explored. Furthermore, we develop new formulas for computations in free post-Lie algebras and D-algebras, based on recursions in a magma, and we show that Lie--Butcher series are related to invariants of curves described by moving frames.Comment: added discussion of post-Lie algebroid

Modeling pulmonary alveolar microlithiasis by epithelial deletion of the Npt2b sodium phosphate cotransporter reveals putative biomarkers and strategies for treatment

Pulmonary alveolar microlithiasis (PAM) is a rare, autosomal recessive lung disorder associated with progressive accumulation of calcium phosphate microliths. Inactivating mutations in SLC34A2, which encodes the NPT2b sodiumdependent phosphate cotransporter, has been proposed as a cause of PAM.Weshow that epithelial deletion ofNpt2b in mice results in a progressive pulmonary process characterized by diffuse alveolar microlith accumulation, radiographic opacification, restrictive physiology, inflammation, fibrosis, and an unexpected alveolar phospholipidosis. Cytokine and surfactant protein elevations in the alveolar lavage and serum of PAM mice and confirmed in serum from PAM patients identify serum MCP-1 (monocyte chemotactic protein 1) and SP-D (surfactant protein D) as potential biomarkers.Microliths introduced by adoptive transfer into the lungs of wild-typemice produce markedmacrophagerich inflammation and elevation of serum MCP-1 that peaks at 1 week and resolves at 1 month, concomitant with clearance of stones. Microliths isolated by bronchoalveolar lavage readily dissolve in EDTA, and therapeutic wholelung EDTA lavage reduces the burden of stones in the lungs. A low-phosphate diet prevents microlith formation in young animals and reduces lung injury on the basis of reduction in serum SP-D. The burden of pulmonary calcium deposits in established PAM is also diminished within 4 weeks by a low-phosphate diet challenge. These data support a causative role for Npt2b in the pathogenesis of PAM and the use of the PAMmouse model as a preclinical platform for the development of biomarkers and therapeutic strategies

Uniqueness in Discrete Tomography of Delone Sets with Long-Range Order

We address the problem of determining finite subsets of Delone sets $\varLambda\subset\R^d$ with long-range order by $X$-rays in prescribed $\varLambda$-directions, i.e., directions parallel to non-zero interpoint vectors of $\varLambda$. Here, an $X$-ray in direction $u$ of a finite set gives the number of points in the set on each line parallel to $u$. For our main result, we introduce the notion of algebraic Delone sets $\varLambda\subset\R^2$ and derive a sufficient condition for the determination of the convex subsets of these sets by $X$-rays in four prescribed $\varLambda$-directions.Comment: 15 pages, 2 figures; condensed and revised versio