Analysis of certain aspects of canal subirrigation

Canal irrigation provides water to crop roots by controlling the level of the water table. Parallel earthen canals spaced throughout the field are filled with water which seeps out into the soil. Under the right environmental conditions, such as fields underlain by a low permeability layer, a properly designed system will maintain saturated conditions just below the root zone of the crop which will result in the correct proportions of water and air in the root zone. A finite element numerical model was used to analyze multiple variations in canal design and impermeable layer depth. An analytical equation was developed from the results for the purpose of providing a relatively simple yet accurate method for the design of such irrigation systems. A site for installation of a pilot scale project was selected in collaboration with colleagues from Njala University, Sierra Leone. Soil samples were collected from the site and instruments were installed to monitor the operating performance of the system. Measured soil properties were entered into the numerical model along with other inputs assuming a worst-case scenario to predict the associated performance. It was concluded that canal irrigation would provide adequate water to crops at the project site. The design equation can be written in the form of q=(8KD_e (n-h_e )+4K(n^2-h_e^2))/L_e where D_e=0.77983D, L_e=0.97185L, h_e=h+0.00452S+0.01301, and q is the seepage rate from the canal (m/day), K is the saturated hydraulic conductivity of the soil (m/day), n is the depth of water in the canal (m), D is the depth from the bed of the canal to the impermeable layer (m), L is the canal spacing (m), h is measured midway between canals as the height of the water table above the bed of the canals (m), and S is the slope of the canal bank (m/m). The dependence of the water table profile upon the shape of the canal has previously been neglected by some authors and studied for cases other than canal irrigation by others

Protocol for the United Kingdom Rotator Cuff Study (UKUFF) : a randomised controlled trial of open and arthroscopic rotator cuff repair

This project was funded by the NIHR Health Technology Assessment programme (project number 05/47/02). J. L. Rees has received a grant from Oxford University which is related to this paper. J. Dawson reports that Oxford University has received a grant from HTA which is related to this paper, as well as a study grant.Peer reviewedPublisher PD

Localized proton NMR spectroscopy in different regions of the human brain in vivo. Relaxation times and concentrations of cerebral metabolites.

High-resolution proton NMR spectra of normal human brain in vivo have been obtained from selected 27- and 64-ml volumes-of-interest (VOI) localized in the insular area, the occipital area, the thalamus, and the cerebellum of normal volunteers. Localization was achieved by stimulated echo (STEAM) sequences using a conventional 1.5-T whole-body MRI system (Siemens Magnetom). The proton NMR spectra show resonances from lipids, lactate, acetate, Nacetylaspartate (NAA), γ-aminobutyrate, glutamine, glutamate, aspartate, creatine and phosphocreatine, choline-containing compounds, taurine, and inositols. While T1 relaxation times of most of these metabolites were about 1100–1700 ms without significant regional differences, their T2 relaxation times varied between 100 and 500 ms. The longest T2 values of about (500 ± 50) ms were observed for the methyl protons of NAA in the white matter of the occipital lobe compared to (320 ± 30) ms in the other parts of the brain. No significant regional T2 differences were found for choline and creatine methyl resonances. The relative concentrations of NAA in gray and white matter were found to be 35% higher than those in the thalamus and cerebellum. Assuming a concentration of 10 mM for total creatine the resulting NAA concentrations of 13–18 mMare by a factor of 2–3 higher than previously reported using analytical techniques. Cerebral lactate reached a maximum concentration of about 1.0 mM

Active Shooter Preparedness Among Dental Hygiene Students

Purpose: Active shooter incidents (ASIs) occurring in dental hygiene academic settings present unique challenges and research examining institutional preparation of dental hygiene students for such incidents is lacking. The purpose of this pilot project was to examine the perceived preparedness, confidence, and awareness of dental hygiene students regarding ASIs. Methods: A validated 24-item electronic survey was distributed to dental hygiene students (n=68) at one institution to measure their preparedness, confidence, and awareness regarding ASIs. Descriptive statistics and Pearson correlations were used for data analysis. Results: Fifty-seven dental hygiene students completed the survey for a response rate of 84%. Many participants felt slightly prepared (n=26, 45.6%) or not prepared (n=15, 26.3%) to respond to an ASI in the classroom. Most were slightly confident (n=26, 45.6%) or not confident (n=16, 26.3%) in helping to control the classroom during an ASI. Over half (n=32, 56.1%) were not certain if their institution provided active shooter trainings and were not certain if drills occurred (n=25,43.8%). Perceived preparedness was positively correlated with confidence in helping to control an ASI in the classroom (r(56)=.616, p=.000). Positive correlations were also identified with perceived preparedness to respond in a lab or clinic with the assumption that ASIs are taken seriously at their institution (r(56)=.375, p=.004). Conclusion: A general lack of preparedness and confidence for responding to ASIs may exist among dental hygiene students along with a lack of awareness regarding trainings and drills. Educational institutions should implement best practices for preparing dental hygiene students for ASIs

Low-Z impurity transport studies using CXRS at ASDEX Upgrade

EUROfusion Consortium 63305

The influence of facies heterogeneity on the doublet performance in low-enthalpy geothermal sedimentary reservoirs

AbstractA three-dimensional model is used to study the influence of facies heterogeneity on energy production under different operational conditions of low-enthalpy geothermal doublet systems. Process-based facies modelling is utilised for the Nieuwerkerk sedimentary formation in the West Netherlands Basin to construct realistic reservoir models honouring geological heterogeneity. A finite element based reservoir simulator is used to model the fluid flow and heat transfer over time. A series of simulations is carried out to examine the effects of reservoir heterogeneity (Net-to-Gross ratio, N/G) on the life time and the energy recovery rate for different discharge rates and the production temperature (Tmin) above which the doublet is working. With respect to the results, we propose a design model to estimate the life time and energy recovery rate of the geothermal doublet. The life time is estimated as a function of N/G, Tmin and discharge rate, while the design model for the energy recovery rate is only a function of N/G and Tmin. Both life time and recovery show a positive relation with an increasing N/G. Further our results suggest that neglecting details of process-based facies modelling may lead to significant errors in predicting the life time of low-enthalpy geothermal systems for N/G values below 70%