2,246 research outputs found
Durability and service life of concrete repairs in the presence of cracks
Engineered Cementitious Composite (ECC) has been proposed to be one of the most promising repair materials due to its unique high ductility and tight crack width control. In concrete repairs, the shrinkage of repair materials is restrained by concrete substrate, and the repair material therefore often cracks. When ECC is used as repair material, the crack width is much smaller compared to normal concrete. The tight crack width of ECC retards the penetration of water and harmful substances and thus enhances the durability of concrete repairs. This paper is aimed to explore the chloride penetration in cracked ECC repairs and to assess the service life of the repair systems. Rapid chloride migration tests was conducted to investigate the chloride penetration profile. Based on the experimental results, the service life of repair systems was evaluated
Total Nuclear Reaction Cross Section Induced by Halo Nuclei and Stable Nuclei
We develop the method for the calculation of the total reaction cross
sections induced by the halo nuclei and stable nuclei. This approach is based
on the Glauber theory, which is valid for nuclear reactions at high energy. It
is extended for nuclear reactions at low energy and intermediate energy by
including both the quantum correction and Coulomb correction under the
assumption of the effective nuclear density distribution. The calculated
results of the total reaction cross section induced by stable nuclei agree well
with the 30 experimental data within 10 percent accuracy.The comparison between
the numerical results and the 20 experimental data for the total nuclear
reaction cross section induced by the neutron halo nuclei and the proton halo
nuclei indicates a satisfactory agreement after considering the halo structure
of these nuclei, which implies the quite different mean fields for the nuclear
reactions induced by halo nuclei and stable nuclei. The halo nucleon
distributions and the root mean square radii of these nuclei can be extracted
from above comparison based on the improved Glauber model, which indicate
clearly the halo structures of these nuclei. Especially, it is clear to see
that the medium correction of the nucleon-nucleon collision has little effect
on the total reaction cross sections induced by the halo nuclei due to the very
weak binding and the very extended density distribution.Comment: 15 pages,2 figures. Communucations in Theoretical Physics, (2003) in
pres
Comparison of endogenous metabolism during long-term anaerobic starvation of nitrite/nitrate cultivated denitrifying phosphorus removal sludges
Denitrifying phosphorus removal (DPR) by denitrifying phosphorus-accumulating organisms (DPAOs) is a promising approach for reducing energy and carbon usage. However, influent fluctuations or interruptions frequently expose the DPAOs biomass to starvation conditions, reducing biomass activity and amount, and ultimately degrading the performance of DPR. Therefore, a better understanding of the endogenous metabolism and recovery ability of DPAOs is urgently required. In the present study, anaerobic starvation (12 days) and recovery were investigated in nitrite- and nitrate-cultivated DPAOs at 20±1°C. The cell decay rates in nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were 0.008day and 0.007day, respectively, being 64% and 68% lower than those of nitrate-DPAOs sludges. Nitrite-DPAOs sludges also recovered more rapidly than nitrate-DPAOs sludge after 12 days of starvation. The maintenance energy of nitrite-DPAOs sludges from the end of the anaerobic and aerobic phase were approximately 31% and 34% lower, respectively, than those of nitrate-DPAOs sludges. Glycogen and polyphosphate (poly-P) sequentially served as the main maintenance energy sources in both nitrite-and nitrate-DPAOs sludges. However, the transformation pathway of the intracellular polymers during starvation differed between them. Nitrate-DPAOs sludge used extracellular polymeric substances (EPS) (mainly polysaccharides) as an additional maintenance energy source during the first 3 days of starvation. During this phase, EPS appeared to contribute to 19-27% of the ATP production in nitrate-DPAOs, but considerably less to the cell maintenance of nitrite-DPAOs. The high resistance of nitrite-DPAOs to starvation might be attributable to frequent short-term starvation and exposure to toxic substances such as nitrite/free nitrous acids in the parent nitrite-fed reactor. The strong resistance of nitrite-DPAOs sludge to anaerobic starvation may be exploited in P removal by shortcut denitrification processes
Semi-quantum private comparison and its generalization to the key agreement, summation, and anonymous ranking
Semi-quantum protocols construct connections between quantum users and
``classical'' users who can only perform certain ``classical'' operations. In
this paper, we present a new semi-quantum private comparison protocol based on
entangled states and single particles, which does not require pre-shared keys
between the ``classical'' users to guarantee the security of their private
data. By utilizing multi-particle entangled states and single particles, our
protocol can be easily extended to multi-party scenarios to meet the
requirements of multiple ``classical'' users who want to compare their private
data. The security analysis shows that the protocol can effectively prevent
attacks from outside eavesdroppers and adversarial participants. Besides, we
generalize the proposed protocol to other semi-quantum protocols such as
semi-quantum key agreement, semi-quantum summation, and semi-quantum anonymous
ranking protocols. We compare and discuss the proposed protocols with previous
similar protocols. The results show that our protocols satisfy the demands of
their respective counterparts separately. Therefore, our protocols have a wide
range of application scenarios.Comment: 19 pages 5 table
Recipient Outcomes after ABO-Incompatible Liver Transplantation: A Systematic Review and Meta-Analysis
BACKGROUND: ABO-incompatible live transplantation (ILT) is not occasionally performed due to a relative high risk of graft failure. Knowledge of both graft and patient survival rate after ILT is essential for donor selection and therapeutic strategy. We systematically reviewed studies containing outcomes after ILT compared to that after ABO-compatible liver transplantation (CLT). METHODOLOGY/PRINCIPAL FINDINGS: We carried out a comprehensive search strategy on MEDLINE (1966-July 2010), EMBASE (1980-July 2010), Biosis Preview (1969-July 2010), Science Citation Index (1981-July 2010), Cochrane Database of Systematic Reviews (Cochrane Library, issue 7, 2010) and the National Institute of Health (July 2010). Two reviewers independently assessed the quality of each study and abstracted outcome data. Fourteen eligible studies were included which came from various medical centers all over the world. Meta-analysis results showed that no significantly statistical difference was found in pediatric graft survival rate, pediatric and adult patient survival rate between ILT and CLT group. In adult subgroup, the graft survival rate after ILT was significantly lower than that after CLT. The value of totally pooled OR was 0.64 (0.55, 0.74), 0.92 (0.62, 1.38) for graft survival rate and patient survival rate respectively. The whole complication incidence (including acute rejection and biliary complication) after ILT was higher than that after CLT, as the value of totally pooled OR was 3.02 (1.33, 6.85). Similarly, in acute rejection subgroup, the value of OR was 2.02 (1.01, 4.02). However, it was 4.08 (0.90, 18.51) in biliary complication subgroup. CONCLUSIONS/SIGNIFICANCE: In our view, pediatric ILT has not been a contraindication anymore due to a similar graft and patient survival rate between ILT and CLT group. Though adult graft survival rate is not so satisfactory, ILT is undoubtedly life-saving under exigent condition. Most studies included in our analysis are observational researches. Larger scale of researches and Randomized-Control Studies are still needed
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