1,483 research outputs found
Adsorption of Chromium Ions by Acid Activated Low Cost Carbon-Kinetic,Thermodynamic and Equilibrium Studies
A carbonaceous adsorbent prepared from an indigenous waste, by acid treatment was tested for its efficiency in removing metal ions. The process parameters studied include agitation time, initial metal ions concentration, carbon dose, pH and temperature. The adsorption followed first order reaction equation and the rate is mainly controlled by intra-particle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Qm) obtained from the Langmuir isotherm plot were found to around 30 mg/g at an initial pH of 7.0. The temperature variation study showed that the metal ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the metal ion solutions. The Langmuir and Freundlich adsorption isotherms obtained, positive ΔH0 value, pH dependent results and desorption of metal ions in mineral acid suggest that the adsorption of metal ions on BBC involves chemisorption as well as physisorption mechanism
Isolation, Characterization and Anti-Inflammatory Property of Thevetia Peruviana
Thevetia peruviana seeds contain glucosides of neriifolin, acetylneriifolin and thevetin. Seed oil distillates of Thevetia peruviana have been found to contain anti-bacterial activity. In the persent work, the fresh flowers of Thevetia peruviana was subjected to phytochemical studies. The results of the study showed that the flowers contain quercetin, kaempferol and quercetin-7-o-galactoside. The structure of the isolated compound was characterized by UV, 1H NMR and 13C NMR spectra. The anti-inflammatory character of the isolated compound was tested by in vitro method and the results of the study revealed that the isolated compound showed a biphasic property
Sociodemographic profiles, educational attainment and physical activity associated with The Daily Mile™ registration in primary schools in England – a national cross-sectional linkage study
Objective To examine primary school and local authority characteristics associated with registration for The Daily Mile (TDM), an active mile initiative aimed at increasing physical activity in children. Design A cross-sectional linkage study using routinely collected data. Setting All state funded primary schools in England from 2012-2018(n=15,815). Results 3,502 of all 15,815(22.1%) state funded primary schools in England were registered to do TDM, ranging from 16% in the East Midlands region to 31% in Inner London. Primary schools registered for TDM had larger mean pupil numbers compared with schools that had not registered (300 vs 269 respectively). There was a higher proportion of TDM registered schools in urban areas compared with non-urban areas. There was local authority variation in the likelihood of school registration (ICC: 0.094). After adjusting for school and local authority characteristics, schools located in a major urban conurbation (OR 1.46 (95%CI:1.24-1.71) urban vs. rural) and schools with a higher proportion of disadvantaged pupils had higher odds of being registered to the TDM (OR 1.16 (95%CI:1.02-1.33)). Area based physical activity and schools’ educational attainment was not significantly associated with registration to TDM. Conclusion One in five primary schools in England has registered for The Daily Mile since 2012. TDM appears to be a wide-reaching school based physical activity intervention that is reaching more disadvantaged primary school populations in urban areas where obesity prevalence is highest. TDM registered schools include those with both high and low educational attainment and are in areas with high and low physical activit
Impact of The Daily Mile on children's physical and mental health, and educational attainment in primary schools: iMprOVE cohort study protocol
INTRODUCTION: School-based active mile initiatives such as The Daily Mile (TDM) are widely promoted to address shortfalls in meeting physical activity recommendations. The iMprOVE Study aims to examine the impact of TDM on children's physical and mental health and educational attainment throughout primary school. METHODS AND ANALYSIS: iMprOVE is a longitudinal quasi-experimental cohort study. We will send a survey to all state-funded primary schools in Greater London to identify participation in TDM. The survey responses will be used for non-random allocation to either the intervention group (Daily Mile schools) or to the control group (non-Daily Mile schools). We aim to recruit 3533 year 1 children (aged 5-6 years) from 77 primary schools and follow them up annually until the end of their primary school years. Data collection taking place at baseline (children in school year 1) and each primary school year thereafter includes device-based measures of moderate-to-vigorous physical activity (MVPA) and questionnaires to measure mental health (Strengths and Difficulties Questionnaire) and educational attainment (ratings from 'below expected' to 'above expected levels'). The primary outcome is the mean change in MVPA minutes from baseline to year 6 during the school day among the intervention group compared with controls. We will use multilevel linear regression models adjusting for sociodemographic data and participation in TDM. The study is powered to detect a 10% (5.5 min) difference between the intervention and control group which would be considered clinically significant. ETHICS AND DISSEMINATION: Ethics has been approved from Imperial College Research Ethics Committee, reference 20IC6127. Key findings will be disseminated to the public through research networks, social, print and media broadcasts, community engagement opportunities and schools. We will work with policy-makers for direct application and impact of our findings
Adsorption of Chromium Ions by Acid Activated Low Cost Carbon-Kinetic,Thermodynamic and Equilibrium Studies
Abstract: A carbonaceous adsorbent prepared from an indigenous waste, by acid treatment was tested for its efficiency in removing metal ions. The process parameters studied include agitation time, initial metal ions concentration, carbon dose, pH and temperature. The adsorption followed first order reaction equation and the rate is mainly controlled by intra-particle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Q m ) obtained from the Langmuir isotherm plot were found to around 30 mg/g at an initial pH of 7.0. The temperature variation study showed that the metal ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the metal ion solutions. The Langmuir and Freundlich adsorption isotherms obtained, positive H 0 value, pH dependent results and desorption of metal ions in mineral acid suggest that the adsorption of metal ions on BBC involves chemisorption as well as physisorption mechanism
3-Aminophenyl naphthalene-1-sulfonate
In the title compound, C16H13NO3S, the plane of the naphthalene ring system forms a dihedral angle of 64.66 (10)° with the benzene ring. The molecular structure is stabilized by weak intramolecular C—H⋯O interactions and the crystal packing is stabilized by weak intermolecular N—H⋯O and C—H⋯O interactions and by π–π stacking interactions of the inversion-related naphthalene units [centroid–centroid distance of 3.7373 (14) Å]
The UTMOST: A hybrid digital signal processor transforms the MOST
The Molonglo Observatory Synthesis Telescope (MOST) is an 18,000 square meter
radio telescope situated some 40 km from the city of Canberra, Australia. Its
operating band (820-850 MHz) is now partly allocated to mobile phone
communications, making radio astronomy challenging. We describe how the
deployment of new digital receivers (RX boxes), Field Programmable Gate Array
(FPGA) based filterbanks and server-class computers equipped with 43 GPUs
(Graphics Processing Units) has transformed MOST into a versatile new
instrument (the UTMOST) for studying the dynamic radio sky on millisecond
timescales, ideal for work on pulsars and Fast Radio Bursts (FRBs). The
filterbanks, servers and their high-speed, low-latency network form part of a
hybrid solution to the observatory's signal processing requirements. The
emphasis on software and commodity off-the-shelf hardware has enabled rapid
deployment through the re-use of proven 'software backends' for its signal
processing. The new receivers have ten times the bandwidth of the original MOST
and double the sampling of the line feed, which doubles the field of view. The
UTMOST can simultaneously excise interference, make maps, coherently dedisperse
pulsars, and perform real-time searches of coherent fan beams for dispersed
single pulses. Although system performance is still sub-optimal, a pulsar
timing and FRB search programme has commenced and the first UTMOST maps have
been made. The telescope operates as a robotic facility, deciding how to
efficiently target pulsars and how long to stay on source, via feedback from
real-time pulsar folding. The regular timing of over 300 pulsars has resulted
in the discovery of 7 pulsar glitches and 3 FRBs. The UTMOST demonstrates that
if sufficient signal processing can be applied to the voltage streams it is
possible to perform innovative radio science in hostile radio frequency
environments.Comment: 12 pages, 6 figure
Five new real-time detections of Fast Radio Bursts with UTMOST
We detail a new fast radio burst (FRB) survey with the Molonglo Radio
Telescope, in which six FRBs were detected between June 2017 and December 2018.
By using a real-time FRB detection system, we captured raw voltages for five of
the six events, which allowed for coherent dedispersion and very high time
resolution (10.24 s) studies of the bursts. Five of the FRBs show temporal
broadening consistent with interstellar and/or intergalactic scattering, with
scattering timescales ranging from 0.16 to 29.1 ms. One burst, FRB181017, shows
remarkable temporal structure, with 3 peaks each separated by 1 ms. We searched
for phase-coherence between the leading and trailing peaks and found none,
ruling out lensing scenarios. Based on this survey, we calculate an all-sky
rate at 843 MHz of events sky day to a fluence
limit of 8 Jy-ms: a factor of 7 below the rates estimated from the Parkes and
ASKAP telescopes at 1.4 GHz assuming the ASKAP-derived spectral index
(). Our results suggest that FRB
spectra may turn over below 1 GHz. Optical, radio and X-ray followup has been
made for most of the reported bursts, with no associated transients found. No
repeat bursts were found in the survey.Comment: 13 pages, 11 figures, submitted to MNRA
Studies on sodium aerosol characteristics for safety studies of sodium cooled fast reactor
26-33The liquid sodium is used as coolant in Sodium cooled Fast Reactors (SFR's). When liquid sodium reacts with air it produced sodium combustion aerosols. These aerosol are very hazardous to the human and corrosive for instruments. In this context, the studies on the physical and chemical characteristics of sodium aerosol are very important for safety of SFR. In this article, the sodium aerosol characteristics and properties produced under normal operation as well as reactor accident are presented. The sodium aerosol in the cover gas region is produced by evaporation and condensation of sodium while in SGB and RCB sodium aerosol are produced by sodium combustion process. The size distribution (Mass Median Diameter-MMD) and concentration of sodium aerosol in cover gas varies from 1.0 to 12 µm and 0.02 to 31.5 g/m3 when temperature of the sodium pool increased from 250-550°C on other hand the MMD of sodium combustion aerosol is varies from 1.0 to 4.0 µm when relative humidity increased from 20 to 95%. The concentration of sodium combustion aerosol in RCB and SGB is 3-4 g/m3. The chemical nature of sodium aerosol in cover gas is pure sodioum (Na) while in SGB and RCB are compounds of sodium (NaOH, Na2CO3 and NaHCO3)
The Thousand-Pulsar-Array program on MeerKAT -- IX. The time-averaged properties of the observed pulsar population
We present the largest single survey to date of average profiles of radio
pulsars, observed and processed using the same telescope and data reduction
software. Specifically, we present measurements for 1170 pulsars, observed by
the Thousand Pulsar Array (TPA) programme at the 64-dish SARAO MeerKAT radio
telescope, in a frequency band from 856 to 1712 MHz. We provide rotation
measures (RM), dispersion measures, flux densities and polarization properties.
The catalogue includes 254 new RMs that substantially increase the total number
of known pulsar RMs. Our integration times typically span over 1000 individual
rotations per source. We show that the radio (pseudo)luminosity has a strong,
shallow dependence on the spin-down energy, proportional to
, that contradicts some previous proposals of population
synthesis studies. In addition, we find a significant correlation between the
steepness of the observed flux density spectra and , and correlations
of the fractional linear polarization with , the spectral index, and
the pulse width, which we discuss in the context of what is known about pulsar
radio emission and how pulsars evolve with time. On the whole, we do not see
significant correlations with the estimated surface magnetic field strength,
and the correlations with are much stronger than those with the
characteristic age. This finding lends support to the suggestion that magnetic
dipole braking may not be the dominant factor for the evolution of pulsar
rotation over the lifetimes of pulsars. A public data release of the
high-fidelity time-averaged pulse profiles in full polarization accompanies our
catalogue.Comment: Accepted for publication in MNRAS. 21 pages, 25 figures, 6 Table
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