The impact of window opening and other occupant behavior on simulated energy performance in residence halls

A poor depiction of occupant behavior in building performance simulation frequently results in substantial divergences between real and simulated results. The problem may be of particular concern with simulation supporting the renovation of older multi-unit residential buildings, buildings whose occupants use windows for temperature control even during heating season. Here, we investigated the impact of window operation models (as well as other occupant behaviors) on simulated energy performance in university residence halls. Based on environmental monitoring, along with information collected from occupant surveys and wearable devices, we estimated air exchange rates and developed a probabilistic window-operation prediction model. The data were collected in 76 dormitory rooms sampled from a pre-renovated historic building and two similar buildings. We then evaluated the window-operation model’s predictive performance in 15 dormitory rooms in the post-renovated building with new occupants. The results of our predictive model were also compared with previously reported window-operation models. We implemented each window-operation model in a calibrated EnergyPlus building performance model, comparing the results of each simulation to metered hourly steam consumption. The impact of the different window operation models on simulated heating energy use was significant (annual error ranging from 0.2% to 10%). Our model demonstrated the highest capability of predicting window state (accuracy=85.8%) and steam use (NMBE=?0.2%); however, some previously published windowoperation models also produced satisfactory performance, implying that such models may be generalizable to some extent. The results suggest that data collected from somewhat ubiquitous indoor environmental quality sensors can glean insights into occupant behavior for building performance simulation. Furthermore, the energy impacts resulting from the variations in occupant behavior studied here were large enough to show that the choice of behavior model can have meaningful implications for real-world applications, such as estimating saving from heating and lighting system upgrades.     

Synthesis and properties of water soluble single‐walled carbon nanotube graft ionic polyacetylene nanocomposites

Water‐soluble single‐walled carbon nanotube‐polyacetylene [SWNT‐PA, SWNT‐P(2EPy‐MeTf)] nanocomposites have been synthesized by using the surface initiated “grafting‐from” method. The FT‐IR spectra confirmed the formation of an amide bond between the functionalized SWNTs and the initiator, 4‐(2‐Aminoethyl) pyridine, to polymerize N‐Methyl‐2‐ethynlypyridinium triflate (2EPy‐MeTf). UV‐vis spectroscopy indicated that the degree of polymerization of P(2EPy‐MeTf) in the SWNT‐polyacetylene composites is 15, based on the Lewis‐Calvin equation. The SWNT‐polyacetylene composites have been characterized by TGA, AFM, and TEM. From TGA analysis, the loading of SWNTs in the SWNT grafted ionic polyacetylenes is estimated to be 22%. AFM and TEM images clearly showed that the nanotube is wrapped with the PA. The SWNT‐polyacetylene composites displayed high water solubility (8 mg/ml). The room temperature electrical conductivity of the doped SWNT‐polyacetylene composites was found to be in the range of 10⁻³ to 10⁻⁴ S/cm, an order of magnitude of increase over neat P(2EPy‐MeTf) and a two order of magnitude increase over Dendrimer‐polyacetylen composites. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers     

Fibroblasts Cultured on Nanowires Exhibit Low Motility,Impaired Cell Division,and DNA Damage

Nanowires are commonly used as tools for interfacing living cells, acting as biomolecule‐delivery vectors or electrodes. It is generally assumed that the small size of the nanowires ensures a minimal cellular perturbation, yet the effects of nanowires on cell migration and proliferation remain largely unknown. Fibroblast behaviour on vertical nanowire arrays is investigated, and it is shown that cell motility and proliferation rate are reduced on nanowires. Fibroblasts cultured on long nanowires exhibit failed cell division, DNA damage, increased ROS content and respiration. Using focused ion beam milling and scanning electron microscopy, highly curved but intact nuclear membranes are observed, showing no direct contact between the nanowires and the DNA. The nanowires possibly induce cellular stress and high respiration rates, which trigger the formation of ROS, which in turn results in DNA damage. These results are important guidelines to the design and interpretation of experiments involving nanowire‐based transfection and electrical characterization of living cells.     

Large-energy-shift photon upconversion in degenerately doped InP nanowires by direct excitation into the electron gas

Realizing photon upconversion in nanostructures is important for many next- generation applications such as biological labelling, infrared detectors and solar cells. In particular nanowires are attractive for optoelectronics because they can easily be electrically contacted. Here we demonstrate photon upconversion with a large energy shift in highly n-doped InP nanowires. Crucially, the mechanism responsible for the upconversion in our system does not rely on multi-photon absorption via intermediate states, thus eliminating the need for high photon fluxes to achieve upconversion. The demonstrated upconversion paves the way for utilizing nanowires--with their inherent flexibility such as electrical contactability and the ability to position individual nanowires--for photon upconversion devices also at low photon fluxes, possibly down to the single photon level in optimised structures.     

Probing the wurtzite conduction band structure using state filling in highly doped InP nanowires

We have grown InP nanowires doped with hydrogen sulfide, which exhibit sulfur concentrations of up to 1.4%. The highest doped nanowires show a pure wurtzite crystal structure, in contrast to bulk InP which has the zinc blende structure. The nanowires display photoluminescence which is strongly blue shifted compared with the band gap, well into the visible range. We find evidence of a second conduction band minimum at the gamma point about 0.23 eV above the band edge, in excellent agreement with recent theoretical predictions. Electrical measurements show high conductivity and breakdown currents of 10(7) A/cm(2).     

The effect of size of sub-sample on mineral analysis values of apple fruits

Apple fruits were divided into opposite sectors of different sizes, and the mineral analyses of the sectors were compared with whole fruit values. Opposite sectors as small 8-12% of whole fruit weight were found to be as representative as larger sectors. There was no evidence of either a constant or a proportional bias arising as a result of sub-sampling. Sub-sampling variation was greater for Ca than for N, P, K and Mg.     

Quinones As Additives During Soda Cooking

Anthraquinone-1-acetic acid is a less effective delignification catalyst than anthraquinone but it gives an enhanced carbohydrate stabilization by converting reducing sugar end groups more effectively to aldonic acid end groups. This reaction produces the hydroquinone form of the additive which is then easily oxidized by oxygen at 80°C. Oxygen treatment favors the end group stabilization. Depolymerization of the cellulose is suppressed by the presence of magnesium hydroxide but cannot be avoided completely.     

Behavior Of Calcium,Magnesium and Manganese Compounds During Oxygen Bleaching of Kraft Pulps

During oxygen bleaching of kraft pulps manganese compounds can, depending on their amounts, the charges of sodium hydroxide and of magnesium protector, and on the presence of trace amounts of catalytically active transition metals retard or promote the depolymerization of the cellulose. The present report deals with pulps pretreated with 2 % nitrogen dioxide. As shown in forthcoming papers similar results were obtained with pulps without pretreatment with nitrogen compounds.

Pretreatment with nitrogen dioxide at 80°C followed by washing with water removed about 95 % of the magnesium and manganese from kraft pulps. Subsequent oxygen bleaching for 180 min removed 40–90 % of the calcium remaining in the pretreated pulps. Produced hydroxycarboxylate ions gave rise to low molecular complexes of calcium and of magnesium, added as protector. Competition for complexing ligands contributed to a decreased dissolution of calcium with increasing addition of magnesium. When magnesium was applied large amounts of colloids of polynuclear magnesium species were produced. These contained lignin fragments and less abundant metal compounds such as manganese and calcium.

Wet oxidation of both low molecular complexing agents and of organic fragments of larger size contributed to a decreased or unchanged concentration of low molecular metal complexes and metal compounds linked to the colloids with hydrated magnesium oxide as the main constituent. The conditions which favored the wet oxidation were similar to those which led to an increased attack on the lignin and carbohydrates in the fibers and thus promoted the dissolution of low molecular metal complexes and the formation of metal ions containing colloids. Under certain conditions precipitation of sparingly soluble manganese compounds of oxidation states higher than +2 had a predominant influence on the concentration of manganese in the liquor.     

Preferential Interface Nucleation: An Expansion of the VLS Growth Mechanism for Nanowires

A review and expansion of the fundamental processes of the vapor–liquid–solid (VLS) growth mechanism for nanowires is presented. Although the focus is on nanowires, most of the concepts may be applicable to whiskers, nanotubes, and other unidirectional growth. Important concepts in the VLS mechanism such as preferred deposition, supersaturation, and nucleation are examined. Nanowire growth is feasible using a wide range of apparatuses, material systems, and growth conditions. For nanowire growth the unidirectional growth rate must be much higher than growth rates of other surfaces and interfaces. It is concluded that a general, system independent mechanism should describe why nanowires grow faster than the surrounding surfaces. This mechanism is based on preferential nucleation at the interface between a mediating material called the collector and a crystalline solid. The growth conditions used mean the probability of nucleation is low on most of the surfaces and interfaces. Nucleation at the collector‐crystal interface is however different and of special significance is the edge of the collector‐crystal interface where all three phases meet. Differences in nucleation due to different crystallographic interfaces can occur even in two phase systems. We briefly describe how these differences in nucleation may account for nanowire growth without a collector. Identifying the mechanism of nanowire growth by naming the three phases involved began with the naming of the VLS mechanism. Unfortunately this trend does not emphasize the important concepts of the mechanism and is only relevant to one three phase system. We therefore suggest the generally applicable term preferential interface nucleation as a replacement for these different names focusing on a unifying mechanism in nanowire growth.     

Xanthine oxidase mediates myocardial injury after hepatoenteric ischemia-reperfusion

OBJECTIVES: To determine if myocardial injury results from hepatoenteric ischemia-reperfusion. We also proposed to determine if this remote heart injury is mediated by a xanthine oxidase-dependent mechanism. DESIGN: Randomized, controlled animal study. SETTING: University-based animal research facility. SUBJECTS: Thirty-six New Zealand white male rabbits, weighing 1.8 to 3 kg. INTERVENTIONS: Anesthetized rabbits were randomly assigned to one of four groups (n = 9 per group): a) a sham-operated group; b) a sham-operated group pretreated with sodium tungstate (xanthine oxidase inactivator); c) an aorta occlusion group; and d) an aorta occlusion group pretreated with sodium tungstate. Descending thoracic aorta occlusion was maintained for 40 mins with a 4-Fr Fogarty embolectomy catheter, followed by 2 hrs of reperfusion. MEASUREMENTS AND MAIN RESULTS: Myocardial injury, manifested by increased circulating creatine kinase-MB fraction activity, was significantly associated with aortic occlusion and reperfusion (p < .05). Sodium tungstate pretreatment significantly (p < .05) reduced circulating and myocardial xanthine oxidase activity. Xanthine oxidase inactivation by sodium tungstate significantly decreased circulating creatine kinase-MB fraction activity after hepatoenteric ischemia-reperfusion (p < .05). Finally, circulating creatine kinase-MB fraction activity was significantly associated with circulating xanthine oxidase activity (r2 = .85; p < .001). CONCLUSIONS: We conclude that remote myocardial injury is caused by hepatoenteric ischemia-reperfusion. The pathoetiology of this myocardial injury involves a xanthine oxidase-dependent mechanism.