246 research outputs found
Energy Analysis of the Texas Capitol Restoration
This paper presents the methodology and results of a detailed energy analysis of the Texas Capitol Restoration. The purpose of this analysis was two-fold: 1) to determine the projected energy cost savings of a series of design alternatives for the Capitol Restoration, and 2) to calibrate the simulation model of the Capitol in its prerestored condition (in September 1991) using monitored energy use data from the Texas LoanSTAR program.
The Capitol in its proposed restored condition was simulated using the DOE-2 building energy analysis computer program with long-term Austin weather data to project the annual energy use, peak electric demand, and annual energy cost. Then a series of 13 energy efficient design altematives was simulated. The results were compared to those of the base case to determine the projected annual energy and energy cost savings for each measure, and for combinations of several of the measures.
Finally, the paper documents the calibration of the DOE-2 model for the Capitol in its prerestored condition, using monitored hourly whole-building electric data (excluding heating and cooling energy)
Determination of Retrofit Savings Using a Calibrated Building Energy Simulation Model
This paper presents the development of a
methodology to determine retrofit energy savings in
buildings when few measured preretrofit data are
available. Calibration of the DOE-2 building energy
analysis computer program for a 250,000 ft2 building
at The University of Texas at Austin, using hourly
data for a two-month preretrofit period, is detailed..
The process begins with the identification of the
DOE-2 input parameters having the greatest
uncertainty. Field measurements then determine
those uncertain parameters that have a significant
impact on total energy use. Finally, the few
remaining parameters are systematically adjusted to
match the preretrofit data. Using the calibrated
model run for the postretrofit period, energy savings
were calculated for whole-building electric, cooling,
and heating energy use, and were compared with
savings calculated using a regression model
developed under the LoanSTAR program. Finally, to
validate the model, postretrofit DOE-2 results were
compared with measured postretrofit data for a seven-month
period
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Formation of a buried soft layer in SiC for compliant substrate by ion implantation
Radiation damage and its removal have been studied in ion implanted 6H-SiC by Rutherford backscattering/Channeling (RBS). They have implanted Ga and Ti at 800 C using doses of 1 {times} 10{sup 16} to 2 {times} 10{sup 17} cm{sup {minus}2}. The implanted samples have been subsequently annealed at 1,050 C, and then at 1,400 C for 30 sec to study the removal of damage produced during implantation. The energies of implanted species have been chosen to obtain 20--40 nm projected ranges to form a buried metallic or graphitic layer. No significant damage removal has been observed after 1,050 C anneal, however 1,400 C annealing of 40 and 120 keV Ga implanted samples (fluence 2 {times} 10{sup 16} cm{sup {minus}2}) resulted in significantly less damage as can be observed from RBS/Channeling data. In the case of Ti implanted samples annealing led to an appreciable increase in the channeled backscattering yield, which might be due to the formation of some new phase (e.g., TiSi or TiSi{sub 2}) and may be related to distortions of the existing lattice
Improved Near Surface Heavy Impurity Detection by a Novel Charged Particle Energy Filter Technique
As the typical feature size of silicon integrated circuits, such as in VLSI technology, has become smaller, the surface cleanliness of silicon wafers has become more important. Hence, detection of trace impurities introduced during the processing steps is essential. A novel technique, consisting of a ``Charged Particle Energy Filter (CPEF)`` used in the path of the scattered helium ions in the conventional Rutherford Backscattering geometry, is proposed and its merits and limitations are discussed. In this technique, an electric field is applied across a pair of plates placed before the detector so that backscattered particles of only a selected energy range go through slits to strike the detector. This can be used to filter out particles from the lighter substrate atoms and thus reduce pulse pileup in the region of the impurity signal. The feasibility of this scheme was studied with silicon wafers implanted with 1{times}10{sup 14} and 1{times}10{sup 13} {sup 54}Fe/cm{sup 2} at an energy of 35 keV, and a 0.5 MeV He{sup +} analysis beam. It was found that the backscattered ion signals from the Si atoms can be reduced by more than three orders of magnitude. This suggests the detection limit for contaminants can be improved by at least two orders of magnitude compared to the conventional Rutherford Backscattering technique. This technique can be incorporated in 200--300 kV ion implanters for monitoring of surface contaminants in samples prior to implantation
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Ion implantation of epitaxial GaN films: damage, doping and activation
Single-crystal GaN films grown on AlN buffer layers previously deposited on 6H-SiC(0001) were studied for radiation damage and its recovery using Rutherford backscattering/channeling, photoluminescence, and cross-sectional TEM. The highest fluence of (1e15 cm{sup -2}) 110 keV Mg and 160 keV Si produced little damage at implantation temperature 550 C. RT damage was higher for same fluences compared to 550 C implantation. The damage was partially annealed by RTA at 1000 C, however, this was not enough to recover the PL signal even for the lowest fluence (1e14 cm{sup -2}). XTEM of as-implanted samples revealed small clusters of defects extended beyond the projected ion range. To recover damage completely, perhaps one needs to go either much higher RTA temperature and/or implant samples in a smaller fluence increment and anneal in between implants to recover the damage
Modeling resilience and sustainability in ancient agricultural systems
The reasons why people adopt unsustainable agricultural practices, and the ultimate environmental implications of those practices, remain incompletely understood in the present world. Archaeology, however, offers unique datasets on coincident cultural and ecological change, and their social and environmental effects. This article applies concepts derived from ecological resilience thinking to assess the sustainability of agricultural practices as a result of long-term interactions between political, economic, and environmental systems. Using the urban center of Gordion, in central Turkey, as a case study, it is possible to identify mismatched social and ecological processes on temporal, spatial, and organizational scales, which help to resolve thresholds of resilience. Results of this analysis implicate temporal and spatial mismatches as a cause for local environmental degradation, and increasing extralocal economic pressures as an ultimate cause for the adoption of unsustainable land-use practices. This analysis suggests that a research approach that integrates environmental archaeology with a resilience perspective has considerable potential for explicating regional patterns of agricultural change and environmental degradation in the past
Loss of the interferon-γ-inducible regulatory immunity-related GTPase (IRG), Irgm1, causes activation of effector IRG proteins on lysosomes, damaging lysosomal function and predicting the dramatic susceptibility of Irgm1-deficient mice to infection
The interferon-γ (IFN-γ)-inducible immunity-related GTPase (IRG), Irgm1, plays an essential role in restraining activation of the IRG pathogen resistance system. However, the loss of Irgm1 in mice also causes a dramatic but unexplained susceptibility phenotype upon infection with a variety of pathogens, including many not normally controlled by the IRG system. This phenotype is associated with lymphopenia, hemopoietic collapse, and death of the mouse.Deutscher Akademischer Austausch Dienst (DAAD); International Graduate School in Development Health
and Disease (IGS-DHD); Deutsche For-schungsgemeinschaft (SFBs 635, 670, 680); Max-Planck-Gesellschaft (Max Planck Fellowship)
‘Sons of athelings given to the earth’: Infant Mortality within Anglo-Saxon Mortuary Geography
FOR 20 OR MORE YEARS early Anglo-Saxon archaeologists have believed children are underrepresented in the cemetery evidence. They conclude that excavation misses small bones, that previous attitudes to reporting overlook the very young, or that infants and children were buried elsewhere. This is all well and good, but we must be careful of oversimplifying compound social and cultural responses to childhood and infant mortality. Previous approaches have offered methodological quandaries in the face of this under-representation. However, proportionally more infants were placed in large cemeteries and sometimes in specific zones. This trend is statistically significant and is therefore unlikely to result entirely from preservation or excavation problems. Early medieval cemeteries were part of regional mortuary geographies and provided places to stage events that promoted social cohesion across kinship systems extending over tribal territories. This paper argues that patterns in early Anglo-Saxon infant burial were the result of female mobility. Many women probably travelled locally to marry in a union which reinforced existing social networks. For an expectant mother, however, the safest place to give birth was with experience women in her maternal home. Infant identities were affected by personal and legal association with their mother’s parental kindred, so when an infant died in childbirth or months and years later, it was their mother’s identity which dictated burial location. As a result, cemeteries central to tribal identities became places to bury the sons and daughters of a regional tribal aristocracy
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