3,715 research outputs found

    Soil Aquifer Treatment for wastewater reclamation in a high water demand society

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    Water resources around the world are under increasing pressure from the rapidly growing demands of rising population and industrialization. Furthermore, changes in global weather patterns are expected to intensify its current and future stresses. In the present study, knowledge and perceptions towards wastewater reclamation for potable and non-potable uses were investigated by the used of an on-line survey distributed amongst the university community at Western university. Subsequent statistical analysis of the results was performed using IBM-SPSS software. Survey results show that member of the university community are more likely to accept reclaimed wastewater for applications that do not involve drinking or close personal contact. However, acceptability improves when benefits to the environment are extensive, it is safe for humans, the source of reclaimed water is perceived as cleaner than municipal wastewater, and the reclaimed wastewater is put back into natural systems with long retention times such as aquifers. Knowledge of the urban water cycle and water resources in Canada is moderate among the university community and the Gamma measure of association shows that there is a moderate (0.303) positive relationship between “water knowledge” and “close contact acceptability”. The majority of the university community (75.8 %) thinks that reclaiming water to provide an alternate source of water in southwestern Ontario is a good idea, but there are still concerns with the presence of chemicals such as pharmaceuticals from reclaimed water and the long-term effects on human health from exposure to these contaminants. Additionally, the suitability of the predominant soils of southwestern Ontario for Soil Aquifer Treatment (SAT) of secondary effluents and combine sewers overflows (CSOs) was investigated by the use of a laboratory scale SAT system operated at three hydraulic retention times. Samples were analyzed for dissolved nitrate, sulphate and phosphate ions, ammonia nitrogen, total nitrogen, total coliforms, E. coli, dissolved organic carbon (DOC), dissolved oxygen and biological oxygen demand (BOD5). Results show that prevalent soils of southwestern Ontario have the ability to further polish secondary effluents in terms of organic matter, E.coli and total coliforms. However, issues with the persistence of nitrates affects its suitability for potable aquifer recharge. Quality of CSOs was slightly improved, however sustainable SAT for non-potable or potable aquifer recharge is not achievable due to low removal of biological contamination, potential for high nitrate concentrations in the effluent and media clogging

    Black hole shadow of a rotating polytropic black hole by the Newman--Janis algorithm without complexification

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    In this work, starting from a spherically symmetric polytropic black hole, a rotating solution is obtained by following the Newman--Janis algorithm without complexification. Besides studying the horizon, the static conditions and causality issues of the rotating solution, we obtain and discuss the shape of its shadow. Some other physical features as the Hawking temperature and emission rate of the rotating polytropic black hole solution are also discussed.Comment: 9 pages, 2 figures, some references adde

    Titchmarsh Theorems for H\"older-Lipschitz functions on profinite groups

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    In this note we extend to metrizable profinite groups the classical theorems of Titchmarsh on the Fourier transform of H\"older-Lipschitz functions. This generalizes the results of Younis on compact zero-dimensional abelian groups to the noncommutative case, and proves a relation between the H\"older-Lipschitz-continuity of functions and their Sobolev regularity given in terms of the Vladimirov-Taibleson operator. Since the class of profinite groups is fairly big, the formulation of our results requires to impose a special condition on the representation theory of the group. We prove that in particular such condition is satisfied by compact nilpotent metrizable profinite groups, which covers the case of compact nilpotent \ell-adic Lie groups. In addition, we study the modulus of continuity of L2L^2-functions on the group, the functional spaces related to it, and its relation to the L2L^2-based H\"older-Lipschitz spaces. Finally, we also derive a characterization for Dini-Lipschitz classes on metrizable profinite groups in terms of the behavior of their Fourier coefficients

    Radiative non-isothermal Bondi accretion onto a massive black hole

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    In this paper, we present the classical Bondi accretion theory for the case of non-isothermal accretion processes onto a supermassive black hole (SMBH), including the effects of X-ray heating and the radiation force due to electron scattering and spectral lines. The radiation field is calculated by considering an optically thick, geometrically thin, standard accretion disk as the emitter of UV photons and a spherical central object as a source of X-ray emission. In the present analysis, the UV emission from the accretion disk is assumed to have an angular dependence, while the X-ray/central object radiation is assumed to be isotropic. This allows us to build streamlines in any angular direction we need to. The influence of both types of radiation is evaluated for different flux fractions of the X-ray and UV emissions with and without the effects of spectral line driving. We find that the radiation emitted near the SMBH interacts with the infalling matter and modifies the accretion dynamics. In the presence of line driving, a transition resembles from pure type 1 & 2 to type 5 solutions (see Fig2.1 of Frank etal. 2002), which takes place regardless of whether or not the UV emission dominates over the X-ray emission. We compute the radiative factors at which this transition occurs, and discard type 5 solution from all our models. Estimated values of the accretion radius and accretion rate in terms of the classical Bondi values are also given. The results are useful for the construction of proper initial conditions for time-dependent hydrodynamical simulations of accretion flows onto SMBH at the centre of galaxies.Comment: 10 pages, 10 figures, Accepted to be published in A&

    Structure and bonding of halonium compounds

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    The geometrical parameters and the bonding in [D···X···D]+ halonium compounds, where D is a Lewis base with N as the donor atom and X is Cl, Br, or I, have been investigated through a combined structural and computational study. Cambridge Structural Database (CSD) searches have revealed linear and symmetrical [D···X···D]+ frameworks with neutral donors. By means of density functional theory (DFT), molecular electrostatic potential (MEP), and energy decomposition analyses (EDA) calculations, we have studied the effect of various halogen atoms (X) on the [D···X···D]+ framework, the effect of different nitrogen-donor groups (D) attached to an iodonium cation (X = I), and the influence of the electron density alteration on the [D···I···D]+ halonium bond by variation of the R substituents at the N-donor upon the symmetry, strength, and nature of the interaction. The physical origin of the interaction arises from a subtle interplay between electrostatic and orbital contributions (σ-hole bond). Interaction energies as high as 45 kcal/mol suggest that halonium bonds can be exploited for the development of novel halonium transfer agents, in asymmetric halofunctionalization or as building blocks in supramolecular chemistry

    Beyond the software: The importance of personal communication to ensure access in complex ILL and other borrowing transactions

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    This paper focuses on the ILL aspects of a larger project investigating the continued availability of items identified in a 1991 bibliography (Dillard). For this stage of the research, the particular focus was on obtaining various theses and dissertations, as well as books and sheet music items. As Lowry (2006) noted, especially in the humanities and social sciences, the majority of dissertation and thesis research has traditionally not resulted in further publication, with only about 10% of this work being republished in other forms. This means that the original works are the only source of this research, and therefore there is a need for continued access. While aggregated databases such as ProQuest Dissertation and Theses Global provide instant full text access in many cases, other items are only available for separate purchase through the database, by borrowing through ILL channels, for download from individual institutional repositories, or for viewing in the library of the degree-granting institution (Smith, 2023). There are also issues in identifying more recent dissertation and theses research as there is no one universal source, but rather a proliferation of different directories and research databases where they may be listed, or they may only be listed within a single institutional repository (Center for Research Libraries, n.d.). Despite the many difficulties encountered, one theme emerged from these retrieval endeavors: the importance of personal communication in overcoming barriers and ensuring access to materials. This paper highlights the different ways in which establishing communication promoted understanding firstly between the ILL librarian and the researcher, and then at each stage of the borrowing process, resulting in mostly successful transactions. Communication was able to overcome barriers of the borrowing institution’s ILL policy that previously prevented successful transactions; it enabled navigation through complex and multi-stage digitization requests involving international universities and national libraries; it enabled direct digitization and electronic delivery of items at no cost to the borrower; and it enabled identification and retrieval of items from institutional repositories

    Inclusion of Secale cereale and Pentosanases in the Ration of Laying Hens: Exploring its Effect on Egg Production and Concentrate Intake and Searching the Optimal Combination in a Diet

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    Background and Objective: Antinutritional factors are usually found in cereals, these correspond to molecular complexes structured by carbohydrates present in the grains, which increase the viscosity of the food bolus, resulting in diminished organic matter digestibility, food intake and egg production. These polymers are known as soluble non-starch polysaccharides (NSPs). The objective of this experiment was to assess the effect of incorporating Secale cereale (SEc) and pentosanases (EEp) in the diets of laying hens (Lohmann LSL hybrid) on their egg production (EP) and concentrate consumption (CC), optimal combination between the main factors was estimated for EP and CC. Materials and Methods: The trial was carried out on a commercial egg-producing poultry farm (Valparaíso Region, Chile). A completely randomized experimental design was used, with a 4×5 factorial arrangement of two factors (four levels for SEc and five levels for EEp). Ten repetitions were used per treatment, where each experimental unit corresponded to one cage with five hens. A contour curvature analysis was carried out to determine the optimal level of inclusion of SEc with EEp. The experimental period lasted 84 days. Results: There was an interaction effect of SEc and EEp on EP and CC. The optimum level of inclusion for EP was 200 g kg–1 SEc and 1 g kg–1 EEp, with average production of 396 units, for CC, the optimum value observed corresponded to 200 g kg–1 SEc with 0.5 g kg–1 EEp (47.56 kg). The lowest EP and CC responses, regardless of the EEp level in the diet, was observed with the inclusion of 600 g kg–1 SEc. The contour area curvature analysis for EP gave a high response curve zone between 130-390 g kg–1 SEc and 0.38-1.57 g kg–1 EEp, the highest response levels for CC were 120-350 g kg–1 SEc and 0.43-1.75 g kg–1 EEp. Conclusion: In this research it was possible to establish that high level of SEc inclusion in the diet affects negatively eggs production and concentrate intake. However, when pentosanases are included in the diet improve these variables. These results suggest possible antinutritional factors of SEc that could have caused negative effects on the hens' physiological response

    Management of Obstructive Hydrocephalus Associated with Pineal Region Cysts and Tumors and Its Implication in Long-Term Outcome

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    BACKGROUND: Different treatment options have been proposed for obstructive hydrocephalus associated with pineal lesions. We discuss the obstructive hydrocephalus management associated with pineal region tumors and cysts in Helsinki Neurosurgery. METHODS: In this article, hydrocephalus treatment by tumor-cyst removal (n = 40), shunt surgery (n = 25), and endoscopic ventriculostomies (n = 3) is evaluated in 68 patients with obstructive hydrocephalus among 136 patients with pineal region tumor and cyst. Multivariate statistical analysis was followed by univariate and multivariate regression models of last functional status, last tumor-free imaging, and disease-specific mortality of the study population. RESULTS: Preoperative hydrocephalus was linked to higher World Health Organization tumor grades, poor functional status, higher mortality, and incomplete resection of pineal region cysts and tumors. Preoperative hydrocephalus remained a predictor of poor last functional status after multivariate regression. Pineal lesion removal with the posterior third ventricle opening as primary hydrocephalus treatment resulted in better last functional status, fewer postoperative shunts, fewer hydrocephalus related procedures, and fewer postoperative infections than in the shunt-treatment group. Multivariate regression analysis linked higher World Health Organization tumor & nbsp;grade, poor immediate functional status, postoperative complications, and incomplete surgical resection as independent predictors of disease mortality in patients with hydrocephalus. Same variables (except immediate modified Rankin Scale score) and higher number of shunt surgeries became independent predictors of poor last functional status at multivariate analysis. Incomplete resection was the only independent predictor of tumor-free magnetic resonance imaging at the last evaluation. CONCLUSIONS: Direct removal of pineal lesions with the opening of the posterior third ventricle could represent effective and reliable management of the associated obstructive hydrocephalus. Further research is required to generalize our inferences.Peer reviewe
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