445 research outputs found

    Process studies of odour emissions from effluent ponds using machine-based odour measurement

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    Replicable experimental studies using a novel experimental facility and a machine-based odour quantification technique were conducted to demonstrate the relationship between odour emission rates and pond loading rates. The odour quantification technique consisted of an electronic nose, AromaScan A32S, and an artificial neural network. Odour concentrations determined by olfactometry were used along with the AromaScan responses to train the artificial neural network. The trained network was able to predict the odour emission rates for the test data with a correlation coefficient of 0.98. Time averaged odour emission rates predicted by the machine-based odour quantification technique, were strongly correlated with volatile solids loading rate, demonstrating the increased magnitude of emissions from a heavily loaded effluent pond. However, it was not possible to obtain the same relationship between volatile solids loading rates and odour emission rates from the individual data. It is concluded that taking a limited number of odour samples over a short period is unlikely to provide a representative rate of odour emissions from an effluent pond. A continuous odour monitoring instrument will be required for that more demanding task

    Dynamical and stationary critical behavior of the Ising ferromagnet in a thermal gradient

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    In this paper we present and discuss results of Monte Carlo numerical simulations of the two-dimensional Ising ferromagnet in contact with a heat bath that intrinsically has a thermal gradient. The extremes of the magnet are at temperatures T1<Tc<T2T_1<T_c<T_2, where TcT_c is the Onsager critical temperature. In this way one can observe a phase transition between an ordered phase (TTcTT_c) by means of a single simulation. By starting the simulations with fully disordered initial configurations with magnetization m0m\equiv 0 corresponding to T=T=\infty, which are then suddenly annealed to a preset thermal gradient, we study the short-time critical dynamic behavior of the system. Also, by setting a small initial magnetization m=m0m=m_0, we study the critical initial increase of the order parameter. Furthermore, by starting the simulations from fully ordered configurations, which correspond to the ground state at T=0 and are subsequently quenched to a preset gradient, we study the critical relaxation dynamics of the system. Additionally, we perform stationary measurements (tt\rightarrow\infty) that are discussed in terms of the standard finite-size scaling theory. We conclude that our numerical simulation results of the Ising magnet in a thermal gradient, which are rationalized in terms of both dynamic and standard scaling arguments, are fully consistent with well established results obtained under equilibrium conditions

    Knowledge of pelvic floor problems: a study of third trimester, primiparous women

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    INTRODUCTION AND HYPOTHESIS: Pelvic floor problems in women (urinary incontinence, faecal incontinence, uterovaginal prolapse) are common, and have an adverse effect on quality of life. We hypothesized that there is low knowledge of these problems amongst primiparous women in their third trimester of pregnancy. METHODS: We conducted a cross-sectional study in antenatal clinics of three hospitals in London, UK, from 2011 to 2013. Primiparous women aged ≥18 years and in the third trimester of pregnancy answered questions on pelvic floor problems. Knowledge scores were calculated based on the proportion of questions answered correctly. RESULTS: A total of 249 women completed the question set. The average knowledge score across all domains was low at 45 %. Scores were lowest for the less common problems of faecal incontinence (35 %) and prolapse (36 %). The score for urinary incontinence was higher at 63 %, but low when questions explored more detailed levels of knowledge (41 %). Knowledge scores were positively associated with both education to tertiary level and the use of books as the information source on pregnancy and delivery. Only 35 % of women cited antenatal classes as a source. CONCLUSIONS: Knowledge of pelvic floor problems is low amongst third-trimester, primiparous women in this London-based population. Adequate knowledge of these problems is important for women to be able to make informed choices about their antenatal care and to seek help if problems arise. The data suggest scope for health-care professionals to raise these issues early during pregnancy, and to help women access accurate sources of information

    Magnetism and Mössbauer study of formation of multi-core γ-Fe2O3 nanoparticles

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    A systematic investigation of magnetic nanoparticles and the formation of a core-shell structure, consisting of multiple maghemite (γ-Fe2O3) nanoparticles as the core and silica as the shell, has been performed using various techniques. High-resolution transmission electron microscopy clearly shows isolated maghemite nanoparticles with an average diameter of 13?nm and the formation of a core-shell structure. Low temperature Mössbauer spectroscopy reveals the presence of pure maghemite nanoparticles with all vacancies at the B-sites. Isothermal magnetization and zero-field-cooled and field-cooled measurements are used for investigating the magnetic properties of the nanoparticles. The magnetization results are in good accordance with the contents of the magnetic core and the non-magnetic shell. The multiple-core γ-Fe2O3 nanoparticles show similar behavior to isolated particles of the same size.We thank the assistance by Dr. Peter Klavins at the Department of Physics, the University of California Davis, in performing the magnetization measurements. This research was partially supported by the Department of Energy, Office of Nuclear Energy, Nuclear Energy Program, under Grant No. DE-NE000070

    Healthy Firms: Constraints to Growth among Private Health Sector Facilities in Ghana and Kenya

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    Background: Health outcomes in developing countries continue to lag the developed world, and many countries are not on target to meet the Millennium Development Goals. The private health sector provides much of the care in many developing countries (e.g., approximately 50 percent in Sub-Saharan Africa), but private providers are often poorly integrated into the health system. Efforts to improve health systems performance will need to include the private sector and increase its contributions to national health goals. However, the literature on constraints private health care providers face is limited. Methodology/Principal Findings: We analyze data from a survey of private health facilities in Kenya and Ghana to evaluate growth constraints facing private providers. A significant portion of facilities (Ghana: 62 percent; Kenya: 40 percent) report limited access to finance as the most significant barrier they face; only a small minority of facilities report using formal credit institutions to finance day to day operations (Ghana: 6 percent; Kenya: 11 percent). Other important barriers include corruption, crime, limited demand for goods and services, and poor public infrastructure. Most facilities have paper-based rather than electronic systems for patient records (Ghana: 30 percent; Kenya: 22 percent), accounting (Ghana: 45 percent; Kenya: 27 percent), and inventory control (Ghana: 41 percent; Kenya: 24 percent). A majority of clinics in both countries report undertaking activities to improve provider skills and to monitor the level and quality of care they provide. However, only a minority of pharmacies report undertaking such activities
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