Sorption of Cd(II) and Pb(II) ions by nanolimestone from underground water samples from Tehama region of Saudi Arabia

333-340Powdered nano limestone (NLS) has been investigated as an in-expensive adsorbent for removal of heavy toxic metals such as cadmium and lead from aqueous solutions. Batch experiments has been carried out, the favorable pH for maximum metals adsorption is found to be 6.8 for both. The surface area has increased in case of NLS up to 6.2 m2/g. The adsorption capacity calculated by Langmuir equation is found to be 75.1 mg/g for Cd (II) and 68.4 for Pb (II) ions at pH 6.8. The adsorption capacity has increased with temperature and the kinetics followed a First-order rate equation for both. The enthalpy change (ΔH0) is 25.4 J mol−1 for Cd (II) and 20.8 J mol−1 for Pb (II), while entropy change (ΔS0) is 41.6 J K−1 mol−1 for Cd (II) and 38.7 J K−1 mol−1 Pb (II), which indicate that adsorption process is endothermic and spontaneous in nature. About 25 collected samples of groundwater has been tested and found to be contaminated with cadmium and lead elements with different rates, with using NLS as adsorbent able to remove both metals from the samples. All of the results suggested that the NLS is excellent nano-adsorbents for cadmium and lead contaminated water samples

Nurse-led implementation of ETAT plus is associated with reduced mortality in a children's hospital in Freetown, Sierra Leone

BACKGROUND: In the wake of the Ebola virus disease (EVD) epidemic in Sierra Leone, secondary care facilities faced an increase in admissions with few members of medical staff available to assess and treat patients. This led to long waiting times in hospital outpatient departments. The study was undertaken in the outpatient department of Ola During Children’s Hospital (the tertiary paediatric hospital for Sierra Leone) in the period immediately following the EVD epidemic of 2014–2015. AIMS: This retrospective analysis of operational programme data aimed to assess whether a quality-improvement approach and task-sharing between medical and nursing staff improved the quality of triage and the timeliness of care. METHODS: All staff working in the outpatient department were offered a 4-week training course, followed by on-the-job supervision and support for 6 months. Nurses who successfully completed the course were given responsibility for the initial assessment of sick patients and for prescribing and giving initial treatment. Data were collected at three points: before intervention and at 3 and 6 months after initiation of the intervention. All children presenting to the hospital for medical attention between 0800 and 1400 Monday to Friday were included. Triage assessment by the outpatient nurse was compared to that made by a clinically experienced observer, and the time taken for each child to be triaged, assessed and given initial treatment was recorded. RESULTS:Between months 0 and 6 of the intervention, detection of emergency signs by the triage nurse improved from 30% to 100%, and detection of priority signs improved from 34% to 100%. For children presenting with emergency signs, the median time between triage and full assessment improved from 57 minutes before intervention to 17 minutes at 3 months and 5 minutes at 6 months (p < 0.0005). For the same group, median time between triage and first antibiotic or antimalarial treatment improved from 220 minutes before intervention to 40 minutes at 3 months and 18 minutes at 6 months (p = 0.006). CONCLUSION: The results indicate that, with appropriate training and support, extending the emergency assessment and treatment of sick children to nursing staff in West African hospitals may improve the accuracy of triage and the time to assessment and treatment of children presenting with signs of serious illness

Investigation on Concrete Properties for Nano Silica Concrete by using Different Plasticizers

This paper presents results of the optimal dosage levels of polycarboxylate-based (PSP) (0.4 and 0.8%) and naphthalene-based (NSP) (0.8 and 1.6%) super plasticizers and different water to binder (w/b) ratios (0.4 and 0.45 ) that produce an adequate balance between strength and workability for concrete containing nano-SiO2 (NS) of 1%, 2%, and 3% as cement replacement. These results indicate that For two types super plasticizers mixes. Increasing the w/c ratio from 0.40 to 0.45 increased the slump of all mixes. Either those containing polycarboxylate or naphthalene sulphonate super plasticizer or the control mixes. For polycarboxylate super plasticizer mixes. Decreasing the w/c ratio from 0.45 to 0.40 increased the compressive strength of all mixes. Either those containing polycarboxylate super plasticizer. For naphthalene sulphonate super plasticizer mixes. Increasing the w/c ratio from 0.40 to 0.45 increased the compressive strength of all mixes. Either those containing 0.8 % naphthalene super plasticizer or the control mixes. While decreasing the w/c ratio from 0.45 to 0.40 increased the compressive strength of all mixes. Either those containing 1.6 % naphthalene sulphonate super plasticizer. the use of (1.6 %) sulphonated naphthalene super plasticizer (NSP) with 0.4 w/c ratio reached a gain in strength equivalent to the  use of  (0.8 %) polycarboxylic super plasticizer (PSP) for mix containing 3 % nano silica . the use of (1.6 %)  naphthalene super plasticizer (NSP) with 0.45 w/c ratio reached a gain in strength equivalent to the  use of  (0.8 %) polycarboxylic super plasticizer (PSP) for mix containing 2 % nano silica. Keywords: Nano silica, concrete, plasticizers, workability, strength

Stability of compressible boundary layers over a smooth backward-facing step

An investigation is conducted into the determination of the credibility of interacting boundary layers in predicting compressible subsonic flows over smooth surface imperfections. The case of smooth backward-facing steps is considered. The predicted mean flows are compared with those obtained using a Navier-Stokes solver. Moreover, the linear 2-D compressible stability characteristics of both mean flows are compared. The results show that the interacting boundary-layer formulation produces accurate mean flows that yield accurate linear stability characteristics, such as growth rates and amplification factors

Effect of wall cooling on the stability of compressible subsonic flows over smooth humps and backward-facing steps

The effect of wall cooling on the two-dimensional linear stability of subsonic flows over two-dimensional surface imperfections is investigated. Results are presented for flows over smooth humps and backward-facing steps with Mach numbers up to 0.8. The results show that, whereas cooling decreases the viscous instability, it increases the shear-layer instability and hence it increases the growth rates in the separation region. The coexistence of more than one instability mechanism makes a certain degree of wall cooling most effective. For the Mach numbers 0.5 and 0.8, the optimum wall temperatures are about 80 pct and 60 pct of the adiabatic wall temperature, respectively. Increasing the Mach number decreases the effectiveness of cooling slightly and reduces the optimum wall temperature