175 research outputs found
A Thermal Performance Design Optimization Study for Small Alaskan Rural Schools
1.0 Summary - 1
2.0 Introduction - 3
2.1 Purpose - 5
2.2 Scope - 5
3.0 A Discussion of Thermal Standards - 7
3.1 Recent Federal Government Studies - 8
3.1.1 The ASHRAE Standard - 8
3.1.2 The United States Department of Energy Standard - 11
3.2 Requirements for Standards in Alaska - 18
4.0 Life Cycle Cost Evaluation Technique - 20
4.1 Purpose - 21
4.2 Prototype Building - 26
4.3 Envelope Design Alternatives - 33
4.4 Mechanical System Design Alternatives - 34
4.4.1 Existing Practice - 34
4.4.2 Modeling of Mechanical Systems - 42
4.4.3 Maintenance and Operations Considerations - 55
4.4.4 Cogeneration Concepts - 57
4.5 Electrical System Design Alternatives - 59
4.6 Cost Estimating - 63
4.6.1 Construction Costs for Thermal Envelopes - 63
4.6.2 Construction Costs for Mechanical and Electrical Systems - 64
4.6.3 Analysis of Maintenance Costs - 69
4.7 Statewide Climate and Costs Regions - 71
4.8 Thermal Modeling Techniques - 77
4.8.1 Fuel Inputs - 78
4.8.2 Domestic Hot Water Heating Energy - 78
4.8.3 Internal and Passive Solar Heat Gain - 81
4.8.4 Building Ventilation Scheduling- 83
4.8.5 Model Output - 83
4.8.6 Model Validation - 83
4.9 Methods of Economic Analysis - 84
4.9.1 Analysis of First Costs and Renovation Costs - 86
4.9.2 Analysis of Maintenance and Operations Costs - 86
4.9.3 Analysis of Annual Energy Consumption - 89
4.10 LCC Computer Model T-Load - 89
4.10.1 Program Description - 89
4.10.2 Data Set Organization - 91
4.10.3 Building Cases Considered - 93
4.10.4 Program Output - 94
5.0 Analysis - 97
5.1 Description of Life Cycle Cost Model Results - 98
5.2 Analysis of Results - 102
5.2.1 Design Concepts - 106
5.2.2 Exterior Envelope - 106
5.2.3 Interior Energy Systems -107
5.3 Sensitivity Analysis - 108
6.0 Conclusions - 112
6.1 Optimum Design Concepts -113
6.2 Sensitivity of Results - 114
6.3 Interior Energy Systems - 115
6.4 Applicability of Results - 115
6.5 Summary - 116
7.0 References - 118
8.0 Appendices
Appendix A: T-Load Computer Program Output - A-1
T-Load NES-002 - A-2
T-Load NEE-002 - A-10
T-Load NED-002 - A-18
T-Load HES-002 A-26
T-Load HEE-002 - A-34
T-Load HED-002 - A-42
T-Load NHS-004 - A-50
T-Load NHE-004 - A-60
T-Load NHD-004 - A-70
T-Load HHS-004 - A-80
T-Load HHE-004 - A-90
T-Load HHD-004 - A-100
Appendix B: Total Life Cycle Cost Minimum Plots - B-
A Thermal Performance Design Optimization Study for Small Alaskan Rural Schools
1.0 Summary - 1
2.0 Introduction - 2
2.1 Purpose - 3
2.2 Scope - 4
3.0 A Discussion of Thermal Standards - 5
3.1 Recent Federal Government Studies - 5
3.2 Requirements for Standards in Alaska - 15
4.0 Life Cycle Cost Evaluation Technique - 17
4.1 - Prototype Building - 20
4.2 Envelope Design Alternatives - 27
4.3 Mechanical System Design Alternatives - 32
4.4 Electrical System Design Alternatives - 46
4.5 Cost Estimating - 49
4.5.1 Construction Costs for Thermal Envelopes - 49
4.5.2 Construction Costs for Mechanical and Electrical Systems - 52
4.5.3 Analysis of Maintenance Costs - 57
4.6 Statewide Climate and Costs Regions - 59
4.7 Thermal Modeling Techniques - 62
4.8 Methods of Economic Analysis - 66
4.8.1 Analysis of First Costs and Renovation Costs - 68
4.8.2 - Analysis of Maintenance and Operations Costs - 70
4.8.3 Analysis of Annual Energy Consumption - 72
4.9 LCC Computer Model "MAIN" - 74
5.0 Analysis of Results - 77
5.1 Description of Life Cycle Cost Model Results - 77
5.2 Selection of Least Life Cycle Cost Design Alternatives - 112
6.0 Conclusions and Recommendations - 117
6.1 Conclusions - 117
6.2 Recommendations - 119
7.0 References - 120
8.0 Appendices
Appendix 1: Electrical Systems Design
Appendix 2: Climate Data
Appendix 3: Listing of Analysis Program
Appendix 4: Listing of Program Variables
Appendix 5: Energy Use Summary
Appendix 6: Life Cycle Cost Summar
Transmembrane helix dynamics of bacterial chemoreceptors supports a piston model of signalling.
Transmembrane α-helices play a key role in many receptors, transmitting a signal from one side to the other of the lipid bilayer membrane. Bacterial chemoreceptors are one of the best studied such systems, with a wealth of biophysical and mutational data indicating a key role for the TM2 helix in signalling. In particular, aromatic (Trp and Tyr) and basic (Arg) residues help to lock α-helices into a membrane. Mutants in TM2 of E. coli Tar and related chemoreceptors involving these residues implicate changes in helix location and/or orientation in signalling. We have investigated the detailed structural basis of this via high throughput coarse-grained molecular dynamics (CG-MD) of Tar TM2 and its mutants in lipid bilayers. We focus on the position (shift) and orientation (tilt, rotation) of TM2 relative to the bilayer and how these are perturbed in mutants relative to the wildtype. The simulations reveal a clear correlation between small (ca. 1.5 Å) shift in position of TM2 along the bilayer normal and downstream changes in signalling activity. Weaker correlations are seen with helix tilt, and little/none between signalling and helix twist. This analysis of relatively subtle changes was only possible because the high throughput simulation method allowed us to run large (n = 100) ensembles for substantial numbers of different helix sequences, amounting to ca. 2000 simulations in total. Overall, this analysis supports a swinging-piston model of transmembrane signalling by Tar and related chemoreceptors
Search for the standard model Higgs boson decaying to a bb pair in events with one charged lepton and large missing transverse energy using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a W boson in sqrt(s) = 1.96 TeV p-pbar collision data
collected with the CDF II detector at the Tevatron corresponding to an
integrated luminosity of 9.45 fb-1. In events consistent with the decay of the
Higgs boson to a bottom-quark pair and the W boson to an electron or muon and a
neutrino, we set 95% credibility level upper limits on the WH production cross
section times the H->bb branching ratio as a function of Higgs boson mass. At a
Higgs boson mass of 125 GeV/c2 we observe (expect) a limit of 4.9 (2.8) times
the standard model value.Comment: Submitted to Phys. Rev. Lett (v2 contains clarifications suggested by
PRL
Search for the standard model Higgs boson decaying to a pair in events with no charged leptons and large missing transverse energy using the full CDF data set
We report on a search for the standard model Higgs boson produced in
association with a vector boson in the full data set of proton-antiproton
collisions at TeV recorded by the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45 fb. We
consider events having no identified charged lepton, a transverse energy
imbalance, and two or three jets, of which at least one is consistent with
originating from the decay of a quark. We place 95% credibility level upper
limits on the production cross section times standard model branching fraction
for several mass hypotheses between 90 and . For a Higgs
boson mass of , the observed (expected) limit is 6.7
(3.6) times the standard model prediction.Comment: Accepted by Phys. Rev. Let
Search for the standard model Higgs boson decaying to a bb pair in events with two oppositely-charged leptons using the full CDF data set
We present a search for the standard model Higgs boson produced in
association with a Z boson in data collected with the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.45/fb. In events
consistent with the decay of the Higgs boson to a bottom-quark pair and the Z
boson to electron or muon pairs, we set 95% credibility level upper limits on
the ZH production cross section times the H -> bb branching ratio as a function
of Higgs boson mass. At a Higgs boson mass of 125 GeV/c^2 we observe (expect) a
limit of 7.1 (3.9) times the standard model value.Comment: To be submitted to Phys. Rev. Let
Measurement of the production of a W boson in association with a charm quark in pp collisions at √s = 7 TeV with the ATLAS detector
The production of a W boson in association with a single charm quark is studied using 4.6 fb−1 of pp collision data at s√ = 7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from various parton distribution function parameterisations. The ratio of the strange-to-down sea-quark distributions is determined to be 0.96+0.26−0.30 at Q 2 = 1.9 GeV2, which supports the hypothesis of an SU(3)-symmetric composition of the light-quark sea. Additionally, the cross-section ratio σ(W + +c¯¯)/σ(W − + c) is compared to the predictions obtained using parton distribution function parameterisations with different assumptions about the s−s¯¯¯ quark asymmetry
Search for single top quarks in the tau+jets channel using 4.8 fb of collision data
We present the first direct search for single top quark production using tau
leptons. The search is based on 4.8 fb of integrated luminosity
collected in collisions at =1.96 TeV with the D0 detector
at the Fermilab Tevatron Collider. We select events with a final state
including an isolated tau lepton, missing transverse energy, two or three jets,
one or two of them tagged. We use a multivariate technique to discriminate
signal from background. The number of events observed in data in this final
state is consistent with the signal plus background expectation. We set in the
tau+jets channel an upper limit on the single top quark cross section of
\TauLimObs pb at the 95% C.L. This measurement allows a gain of 4% in expected
sensitivity for the observation of single top production when combining it with
electron+jets and muon+jets channels already published by the D0 collaboration
with 2.3 fb of data. We measure a combined cross section of
\SuperCombineXSall pb, which is the most precise measurement to date.Comment: 12 pages, 5 figure
Are ethnic disparities in HbA1c levels explained by mental wellbeing? Analysis of population-based data from the Health Survey for England
Aims: It is unclear how ethnic differences in HbA1c levels are affected by individual variations in mental wellbeing. Thus, the aim of this study was to assess the extent to which HbA1c disparities between Caucasian and South Asian adults are mediated by various aspects of positive psychological functioning.
Methods: Data from the 2014 Health Survey for England was analysed using bootstrapping methods. A total of 3894 UK residents with HbA1c data were eligible to participate. Mental wellbeing was assessed using the Warwick-Edinburgh Mental Well-Being Scale. To reduce bias BMI, blood pressure, diabetes status, and other factors were treated as covariates.
Results: Ethnicity directly predicted blood sugar control (unadjusted coefficient -2.15; 95% CI -3.64, -0.67), with Caucasians generating lower average HbA1c levels (37.68 mmol/mol (5.6%)) compared to South Asians (39.87 mmol/mol (5.8%)). This association was mediated by positive mental wellbeing, specifically concerning perceived vigour (unadjusted effect 0.30; 95% CI 0.13, 0.58): South Asians felt more energetic than Caucasians (unadjusted coefficient -0.32; 95% CI -0.49, -0.16), and greater perceived energy predicted lower HbA1c levels (unadjusted coefficient -0.92; 95% CI -1.29, -0.55). This mediator effect accounted for just over 14% of the HbA1c variance, and was negated after adjusting for BMI.
Conclusions: Caucasian experience better HbA1c levels compared with their South Asian counterparts. However, this association is partly confounded by individual differences in perceived energy levels, which is implicated in better glycaemic control, and appears to serve a protective function in South Asians
Performance of the CMS Cathode Strip Chambers with Cosmic Rays
The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device
in the CMS endcaps. Their performance has been evaluated using data taken
during a cosmic ray run in fall 2008. Measured noise levels are low, with the
number of noisy channels well below 1%. Coordinate resolution was measured for
all types of chambers, and fall in the range 47 microns to 243 microns. The
efficiencies for local charged track triggers, for hit and for segments
reconstruction were measured, and are above 99%. The timing resolution per
layer is approximately 5 ns
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