269 research outputs found
Comparative study of the noise generated by the moto-compressor and that generated by the turbo-compressor
The fundamental aim of this study is to compare between the noise generated by the moto-compressor and the noise generated by the turbo-compressor operating 24H/24H on the continuous function mode; these two machines make part of the equipment of the GP1Z, a factory of hydrocarbon treatment. To attain the principal objective of this study we divided our work into two parts, in the first part we followed and evaluated the average level of the noise emitted by the two machines, whereas in the second part we studied the noise propagation emitted by the two machines and its impact on the generation of the noise. The results obtained from this study demonstrate that the noise generated by the turbo-compressor is higher than the noise generated by the moto-compressor.Keywords: noise; moto-compressor; turbo-compressor; noise maping
Quantum rotation gates with controlled nonadiabatic evolutions
Quantum gates can be implemented adiabatically and nonadiabatically. Many schemes used at
least two sequentially implemented gates to obtain an arbitrary one-qubit gate. Recently, it has
been shown that nonadiabatic gates can be realized by single-shot implementation. It has also
been shown that quantum gates can be implemented with controlled adiabatic evolutions. In this
paper, we combine the advantage of single-shot implementation with controlled adiabatic
evolutions to obtain controlled nonadiabatic evolutions. We also investigate the robustness to
different types of errors. We find that the fidelity is close to unity for realistic decoherence rate
The Qatar Biobank: background and methods
Background: The Qatar Biobank aims to collect extensive lifestyle, clinical, and biological information from up to
60,000 men and women Qatari nationals and long-term residents (individuals living in the country for ≥15 years)
aged ≥18 years (approximately one-fifth of all Qatari citizens), to follow up these same individuals over the long
term to record any subsequent disease, and hence to study the causes and progression of disease, and disease
burden, in the Qatari population.
Methods: Between the 11th-December-2012 and 20th-February-2014, 1209 participants were recruited into the pilot
study of the Qatar Biobank. At recruitment, extensive phenotype information was collected from each participant,
including information/measurements of socio-demographic factors, prevalent health conditions, diet, lifestyle,
anthropometry, body composition, bone health, cognitive function, grip strength, retinal imaging, total body dual
energy X-ray absorptiometry, and measurements of cardiovascular and respiratory function. Blood, urine, and saliva
were collected and stored for future research use. A panel of 66 clinical biomarkers was routinely measured on
fresh blood samples in all participants. Rates of recruitment are to be progressively increased in the coming period
and the recruitment base widened to achieve a cohort of consented individuals broadly representative of the
eligible Qatari population. In addition, it is planned to add additional measures in sub-samples of the cohort,
including Magnetic Resonance Imaging (MRI) of the brain, heart and abdomen.
Results: The mean time for collection of the extensive phenotypic information and biological samples from each
participant at the baseline recruitment visit was 179 min. The 1209 pilot study participants (506 men and 703
women) were aged between 28–80 years (median 39 years); 899 (74.4 %) were Qatari nationals and 310 (25.6 %)
were long-term residents. Approximately two-thirds of pilot participants were educated to graduate level or above.
Conclusions: The pilot has proven that recruitment of volunteers into the Qatar Biobank project with intensive
baseline measurements of behavioural, physical, and clinical characteristics is well accepted and logistically feasible.
Qatar Biobank will provide a powerful resource to investigate the major determinants of ill-health and well-being in
Qatar, providing valuable insights into the current and future public health burden that faces the country.Qatar Foundation for Education, Science and Community Development and the Supreme Council of Healt
Brane inflation and the fine-tuning problem
Brane inflation can provide a promissing framework for solving the
fine-tuning problem in standard inflationary models. The aim of this paper is
to illustrate the mechanism by which this can be achieved. By considering the
supersymmetric two-stage inflation model it is shown that the initial
fine-tuning of the coupling parameter can be considerably relaxed. SubPlanckian
values of the inflaton during inflation can also be obtained.Comment: 04 pages (Revtex
Patterns of tobacco smoking and nicotine vaping among university students in the united arab emirates: A cross-sectional study
Various forms of tobacco smoking and nicotine vaping tools are available on the market. This study quantified the prevalence of and identified factors associated with patterns of smoking and nicotine vaping among university students in the United Arab Emirates (UAE). A cross-sectional sample of students enrolled in three public universities was surveyed. Self-reported current smoking and nicotine vaping were recorded. Of 1123 students, 81.7% completed the online survey (mean age, 20.7 ± 3.4 (SD) years; 70.7% females). The prevalence of current smoking was 15.1% while the prevalence of current nicotine vaping was nearly 4.0%. Among current smokers, 54.7% reported conventional smoking only, 15.1% reported nicotine vaping only, and 28.8% were poly-users. Conventional midwakh (47.5%), followed by conventional shisha/waterpipe (36.7%), conventional cigarettes (36.7%), electronic shisha/waterpipe (25.2%), and electronic cigarettes (24.5%), were most commonly reported by students. Students aged 20–25 years (adjusted odds ratios (aOR): 2.08, 95% confidence interval (CI): 1.18–3.67) or \u3e25 years (aOR: 4.24, 95% CI: 1.41–12.80) had higher odds of being current smokers compared to those aged 17–19 years. The male gender was also independently associated with higher odds of being a current smoker (aOR: 5.45, 95% CI: 3.31–8.97) as well as higher odds of smoking cigarettes, shisha, and midwakh, or nicotine vaping compared to being female. Of nicotine vaping users, 36.1% reported using nicotine vaping because they enjoyed the flavor and vaporizing experience and 34.4% used it to help them to quit smoking. A relatively high prevalence of self-reported smoking was reported among university students in the UAE. The findings also suggest that nicotine vaping use is relatively widespread, but still less common than traditional smoking. Vigilant and tailored university-based smoking control and preventive measures are warranted
Cross-sections for nuclide production in 56Fe target irradiated by 300, 500,750, 1000, 1500, and 2600 MeV protons compared with data on hydrogen target irradiation by 300, 500, 750, 1000, and 1500 MeV/nucleon 56Fe ions
Cross-sections for radioactive nuclide production in 56Fe(p,x) reactions at
300, 500, 750, 1000, 1500, and 2600 MeV were measured using the ITEP U-10
proton accelerator. In total, 221 independent and cumulative yields of products
of half-lives from 6.6 min to 312 days have been obtained via the
direct-spectrometry method. The measured data have been compared with the
experimental data obtained elsewhere by the direct and inverse kinematics
methods and with calculations by 15 codes, namely: MCNPX (INCL, CEM2k, BERTINI,
ISABEL), LAHET (BERTINI, ISABEL), CEM03 (.01, .G1, .S1), LAQGSM03 (.01, .G1,
>.S1), CASCADE-2004, LAHETO, and BRIEFF. Most of our data are in a good
agreement with the inverse kinematics results and disprove the results of some
earlier activation measurements that were quite different from the inverse
kinematics measurements. The most significant calculation-to-experiment
differences are observed in the yields of the A<30 light nuclei, indicating
that further improvements in nuclear reaction models are needed, and pointing
out as well to a necessity of more complete measurements of such reactions.Comment: 53 pages, 9 figures, 6 tables, only pdf file, submitted to Phys. Rev.
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LFR "Lead-Cooled Fast Reactor"
The main purpose of this paper is to present the current status of development of the Lead-cooled Fast Reactor (LFR) in Generation IV (GEN IV), including the European contribution, to identify needed R&D and to present the corresponding GEN IV International Forum (GIF) R&D plan [1] to support the future development and deployment of lead-cooled fast reactors. The approach of the GIF plan is to consider the research priorities of each member country in proposing an integrated, coordinated R&D program to achieve common objectives, while avoiding duplication of effort. The integrated plan recognizes two principal technology tracks: (1) a small, transportable system of 10-100 MWe size that features a very long refuelling interval, and (2) a larger-sized system rated at about 600 MWe, intended for central station power generation. This paper provides some details of the important European contributions to the development of the LFR. Sixteen European organizations have, in fact, taken the initiative to present to the European Commission the proposal for a Specific Targeted Research and Training Project (STREP) devoted to the development of a European Lead-cooled System, known as the ELSY project; two additional organizations from the US and Korea have joined the project. Consequently, ELSY will constitute the reference system for the large lead-cooled reactor of GEN IV. The ELSY project aims to demonstrate the feasibility of designing a competitive and safe fast power reactor based on simple technical engineered features that achieves all of the GEN IV goals and gives assurance of investment protection. As far as new technology development is concerned, only a limited amount of R&D will be conducted in the initial phase of the ELSY project since the first priority is to define the design guidelines before launching a larger and expensive specific R&D program. In addition, the ELSY project is expected to benefit greatly from ongoing lead and lead-alloy technology development already being carried out in different institutes participating in this STREP. This is particularly true in Europe where a large R&D program associated with the development of Accelerator Driven Systems (ADS) is being actively pursued. The general objective of the ELSY project is to design an innovative lead-cooled fast reactor complemented by an analytical effort to assess the existing knowledge base in the field of lead-alloy coolants (i.e., lead-bismuth eutectic (LBE) and also lead/lithium) in order to extrapolate this knowledge base to pure lead. This analysis effort will be complemented with some limited R&D activities to acquire missing or confirmatory information about fundamental topics for ELSY that are not sufficiently covered in the ongoing European ADS program or elsewhere
The GUINEVERE Project for Accelerator Driven System Physics
paper 9414International audienceThe GUINEVERE project is part of the EUROTRANS Integrated Project of the 6th EURATOM Framework Programme. It is mainly devoted to ADS on-line reactivity monitoring validation, sub-criticality determination and operational procedures (loading, start-up, shut-down, ...) as a follow-up of the MUSE experiments. The project consists in coupling a fast lead core, set-up in the VENUS reactor at SCK*CEN Mol (B), with a GENEPI neutron source under construction by CNRS. To accommodate the accelerator in a vertical coupling configuration, the VENUS building is being heightened. The fast core will be loaded with enriched Uranium and will be moderated and reflected with solid lead (zero power experiment). For the purpose of the experimental programme, the neutron source has to be operated not only in pulsed mode but also in continuous mode to investigate the current-to-flux reactivity indicator in representative conditions of a powerful ADS. In this latter mode it is also required to make short beam interruptions to have access to the neutron population decrease as a function of time: from this spectrum it will be possible to apply different analysis techniques such as "prompt decay" fitting techniques and "source jerk" techniques. Beam interruptions will be repeated at a programmable frequency to improve time spectra statistics. Different sub-criticality levels (keff=0.99, 0.97, 0.95, ...) will be investigated in order to obtain a full set of data points for the final overall validation of the methodology. This paper describes the status of the experimental facility assembling, and the foreseen experimental programme to be started
Hepatoblast and mesenchymal cell-specific gene-expression in fetal rat liver and in cultured fetal rat liver cells
The aim of this study was to determine whether passaged rat fetal liver cells are functional hepatoblasts. Hepatocyte/hepatoblast- and liver myofibroblast-gene-expressions were studied in adult and fetal rat liver tissues as well as in primary and passaged cultures of isolated rat fetal liver cells at both the mRNA and protein level. Desmin- and Alpha-Smooth Muscle Actin (SMA)-positive cells were located in the walls of liver vessels, whereas Desmin-positive/SMA-negative cells were distributed within the liver parenchyma. Primary cultures contained Prox1-positive hepatoblasts, Desmin/SMA-positive myofibroblasts and only a few Desmin-positive/SMA-negative cells. Albumin and alpha-fetoprotein (AFP) could be detected in the primary cultures and to a lesser extent after the first passage. The number of Desmin-positive/SMA-negative cells decreased with successive passage, such that after the second passage, only Desmin/SMA-positive cells could be detected. SMA-gene-expression increased during the passages, suggesting that myofibroblasts become the major cell population of fetal liver cell cultures over time. This observation needs to be taken into account, should passaged fetal liver cells be used for liver cell transplantation. Moreover it contradicts the concept of epithelial-mesenchymal transformation and suggests rather that selective overgrowth of mesenchymal cells occurs in culture
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