The reliability of inverse modelling for the wide scale characterization of the thermal properties of buildings

The reduction of energy use in buildings is a major component of greenhouse gas mitigation policy and requires knowledge of the fabric and the occupant behaviour. Hence there has been a longstanding desire to use automatic means to identify these. Smart metres and the internet-of-things have the potential to do this. This paper describes a study where the ability of inverse modelling to identify building parameters is evaluated for 6 monitored real and 1000 simulated buildings. It was found that low-order models provide good estimates of heat transfer coefficients and internal temperatures if heating, electricity use and CO₂ concentration are measured during the winter period. This implies that the method could be used with a small number of cheap sensors and enable the accurate assessment of buildings’ thermal properties, and therefore the impact of any suggested retrofit. This has the potential to be transformative for the energy efficiency industry.     

Time to clinical stability in patients hospitalized with community-acquired pneumonia: implications for practice guidelines

CONTEXT: Many groups have developed guidelines to shorten hospital length of stay in pneumonia in order to decrease costs, but the length of time until a patient hospitalized with pneumonia becomes clinically stable has not been established. OBJECTIVE: To describe the time to resolution of abnormalities in vital signs, ability to eat, and mental status in patients with community-acquired pneumonia and assess clinical outcomes after achieving stability. DESIGN: Prospective, multicenter, observational cohort study. SETTING: Three university and 1 community teaching hospital in Boston, Mass, Pittsburgh, Pa, and Halifax, Nova Scotia. PATIENTS: Six hundred eighty-six adults hospitalized with community-acquired pneumonia. MAIN OUTCOME MEASURES: Time to resolution of vital signs, ability to eat, mental status, hospital length of stay, and admission to an intensive care, coronary care, or telemetry unit. RESULTS: The median time to stability was 2 days for heart rate (< or =100 beats/min) and systolic blood pressure (> or =90 mm Hg), and 3 days for respiratory rate (< or =24 breaths/min), oxygen saturation (> or =90%), and temperature (< or =37.2 degrees C [99 degrees F]). The median time to overall clinical stability was 3 days for the most lenient definition of stability and 7 days for the most conservative definition. Patients with more severe cases of pneumonia at presentation took longer to reach stability. Once stability was achieved, clinical deterioration requiring intensive care, coronary care, or telemetry monitoring occurred in 1% of cases or fewer. Between 65% to 86% of patients stayed in the hospital more than 1 day after reaching stability, and fewer than 29% to 46% were converted to oral antibiotics within 1 day of stability, depending on the definition of stability. CONCLUSIONS: Our estimates of time to stability in pneumonia and explicit criteria for defining stability can provide an evidence-based estimate of optimal length of stay, and outline a clinically sensible approach to improving the efficiency of inpatient management.     

Triple functionalisation of single-walled carbon nanotubes with doxorubicin, a monoclonal antibody, and a fluorescent marker for targeted cancer therapy

Single-walled carbon nanotubes (SWCNTs) have been identified as a transporter for anti-cancer drugs, as they are capable of penetrating mammalian cell membranes and allow for a high drug loading due to their nanoscale dimensions and high aspect ratio. In addition, they can assist the targeting of therapeutic agents to the desired site of action by conjugation to antibodies or ligands of cancer cell surface receptors, which increases the effectiveness of the treatment and reduces side effects. In this work, we present a method for the triple functionalisation of oxidised SWCNTs with the anti-cancer drug doxorubicin, a monoclonal antibody, and a fluorescent marker at non-competing binding sites. The proposed methodology allows for the targeted delivery of the anti-cancer drug to cancer cells and the visualisation of the cellular uptake of SWCNTs by confocal microscopy. We show that the complex is efficiently taken up by cancer cells with subsequent intracellular release of doxorubicin, which then translocates to the nucleus while the nanotubes remain in the cytoplasm.     

Expertise and category-based induction.

The authors examined inductive reasoning among experts in a domain. Three types of tree experts (landscapers, taxonomists, and parks maintenance personnel) completed 3 reasoning tasks. In Experiment 1, participants inferred which of 2 novel diseases would affect "more other kinds of trees" and provided justifications for their choices. In Experiment 2, the authors used modified instructions and asked which disease would be more likely to affect "all trees." In Experiment 3, the conclusion category was eliminated altogether, and participants were asked to generate a list of other affected trees. Among these populations, typicality and diversity effects were weak to nonexistent. Instead, experts' reasoning was influenced by "local" coverage (extension of the property to members of the same folk family) and causal-ecological factors. The authors concluded that domain knowledge leads to the use of a variety of reasoning strategies not captured by current models of category-based induction. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Assessing the risk of climate change for buildings: A comparison between multi-year and probabilistic reference year simulations

Given a changing climate, there is a need to provide data for future years so that practicing engineers can investigate the impact of climate change on particular designs and examine any risk the client might be exposed to. In addition, such files are of use to building scientists in developing generic solutions to problems such as elevated internal temperatures and poor thermal comfort. With the release of the UK Climate Projections (UKCP09) [1], and the publication of a methodology for the creation of probabilistic future reference years using the UKCP09 weather generator [2], it is possible to model future building performance. However, the collapse of the distribution of possibilities inherent in the UKCP09 method into a single reference year or a small number of reference years, potentially means the loss of most of the information about the potential range of the response of the building and of the risk occupants might be subject to. In this paper we model for the first time the internal conditions and energy use of a building with all 3000 example years produced by the UKCP09 weather generator in an attempt to study the full range of response and risk. The resultant histograms and cumulative distribution functions are then used to examine whether single reference years can be used to answer questions about response and risk under a changing climate, or whether a more probabilistic approach is unavoidable.     

Corrosion potential oscillation of stainless steel in concentrated sulphuric acid: I. Electrochemical aspects

The spontaneous oscillation of corrosion potential between the active and passive states of UNS S30403 stainless steel has been studied in 93.5 wt.% sulphuric acid at 60 °C. Detailed electrochemical analysis of the kinetics of the oscillating potential has suggested the presence of a nickel salt which is stable over a limited potential range. The nickel salt is subject to dissolution at potentials more positive than −0.25 V (MSE), while at lower potentials—less than −0.35 V (MSE)—a stable salt film is formed. A critical coverage of the salt on the surface is the prerequisite for the mixed potential to be shifted into the passive range by an increase in the exchange current density for the sulphuric acid cathodic reaction. However, when the coverage exceeds a critical value, such as can be produced by a potentiostatic hold, the salt effectively blocks the formation of a passive film.     

Dissolution of alumina in mold fluxes

The solubility and rate of dissolution of alumina in a range of mold fluxes in the CaO-Al₂O₃-SiO₂-Na₂O-CaF₂ system have been measured at 1530 °C using the rotating finger method. The solubilities were approximately 38 pct for all fluxes studied. The kinetics of dissolution were correlated with the Levich-Chochran equation for a rotating disc and used to determine the effective diffusivity of alumina. The effective diffusivity was inversely proportional to the viscosity of the flux and showed excellent agreement with previous work on CaO-Al₂O₃-SiO₂ slags. This is in keeping with either the Eyring relation or the Stokes-Einstein relation. The value obtained for the size of the diffusing unit when the Stokes-Einstein relation was used, 1.81 Å, was more reasonable, which is not normally expected for silicate slags. This result is explained by the low level of polymerization in these fluxes.     

A new technique to derive particle size distributions and aerosol number concentrations directly from thermophoretic data

The manufacture of many high value-added powders takes place by the decomposition of gaseous precursors in aerosol tube reactors. Historically, process improvements were achieved by making changes on the outside of the reactor and observing what comes out at the end of the pipe. The development of increasingly accurate aerosol dynamics models based on engineering first principles has been limited because models were typically validated on integral properties of ex situ product, instead of particle properties measured at multiple positions inside the reactor. In this study, a model reactor was equipped to capture samples thermophoretically from 15 internal positions. Additional in-line measurements were achieved with a multi-stage inertial impactor and by traditional analysis of ex situ product. Calculations were performed to verify that thermophoresis was the dominant mechanism of particle capture. The thermophoretic samples were analyzed by electron beam microscopy and image analysis to develop particle size distributions at each of the internal positions inside the reactor. An approximation of Talbot's Equation for thermophoretic velocity allowed experimental measurements to be combined with thermophoretic sample data to give predictions of particle number concentration corresponding to the precise sampling locations. The combinations of particle size distributions and number concentrations provide powerful insights on particle nucleation and growth dynamics.