1,652 research outputs found

    The characterization of feces and urine: a review of the literature to inform advanced treatment technology

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    The safe disposal of human excreta is of paramount importance for the health and welfare of populations living in low income countries as well as the prevention of pollution to the surrounding environment. On-site sanitation (OSS) systems are the most numerous means of treating excreta in low income countries, these facilities aim at treating human waste at source and can provide a hygienic and affordable method of waste disposal. However, current OSS systems need improvement and require further research and development. Development of OSS facilities that treat excreta at, or close to, its source require knowledge of the waste stream entering the system. Data regarding the generation rate and the chemical and physical composition of fresh feces and urine was collected from the medical literature as well as the treatability sector. The data were summarized and statistical analysis was used to quantify the major factors that were a significant cause of variability. The impact of this data on biological processes, thermal processes, physical separators, and chemical processes was then assessed. Results showed that the median fecal wet mass production was 128 g/cap/day, with a median dry mass of 29 g/cap/day. Fecal output in healthy individuals was 1.20 defecations per 24 hr period and the main factor affecting fecal mass was the fiber intake of the population. Fecal wet mass values were increased by a factor of 2 in low income countries (high fiber intakes) in comparison to values found in high income countries (low fiber intakes). Feces had a median pH of 6.64 and were composed of 74.6% water. Bacterial biomass is the major component (25–54% of dry solids) of the organic fraction of the feces. Undigested carbohydrate, fiber, protein, and fat comprise the remainder and the amounts depend on diet and diarrhea prevalence in the population. The inorganic component of the feces is primarily undigested dietary elements that also depend on dietary supply. Median urine generation rates were 1.42 L/cap/day with a dry solids content of 59 g/cap/day. Variation in the volume and composition of urine is caused by differences in physical exertion, environmental conditions, as well as water, salt, and high protein intakes. Urine has a pH 6.2 and contains the largest fractions of nitrogen, phosphorus, and potassium released from the body. The urinary excretion of nitrogen was significant (10.98 g/cap/day) with urea the most predominant constituent making up over 50% of total organic solids. The dietary intake of food and fluid is the major cause of variation in both the fecal and urine composition and these variables should always be considered if the generation rate, physical, and chemical composition of feces and urine is to be accurately predicted

    Individual cognitive-behavioural anger treatment for people with mild-borderline intellectual disabilities and histories of aggression: a controlled trial

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    Objectives - Anger is a significant predictor and activator of violent behaviour in patients living in institutional settings. There is some evidence for the value of cognitive-behavioural treatments for anger problems with people with intellectual disabilities. In this study, a newly designed treatment targeted at anger disposition, reactivity, and control was provided to intellectually disabled offenders with aggression histories living in secure settings. Design - About forty detained patients with mild-borderline intellectual disabilities and histories of serious aggression were allocated to specially modified cognitive-behavioural anger treatment (AT group) or to routine care waiting-list control (RC group) conditions. Methods - AT group participants received 18 sessions of individual treatment. The AT and RC groups were assessed simultaneously at 4 time points: screen, pre- and post-treatment, and at 4-month follow-up using a range of self- and staff-rated anger measures. The effectiveness of the treatment was evaluated using ANCOVA linear trend analyses of group differences on the main outcome measures. Results - The AT group's self-reported anger scores on a number of measures were significantly lower following treatment, compared with the RC wait-list condition, and these improvements were maintained at follow-up. Limited evidence for the effectiveness of treatment was provided by staffs' ratings of patient behaviour post-treatment. Conclusions - Detained men with mild-moderate intellectual disabilities and histories of severe aggression can successfully engage in, and benefit from, an intensive individual cognitive-behavioural anger treatment that also appears to have beneficial systemic effects

    Spaces of Transformation: the Experience of Architecture Students

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    This paper comments on the experiences of a group of architecture students — from the University of Idaho, USA, and from Anglia Ruskin University, UK — who attended a week-long workshop at the Centre for Alternative Technology in Wales, UK. We examine, through student reflection, the transformations experienced and how the collaboration and location has influenced their work and reinterpretation of their lifeworld

    BIOMECHANICAL ANALYSIS OF ACTIVE DRAG IN SWIMMING

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    Active drag measurement through an entire swimming stroke was computed from the swimmer’s maximum sprint speed and the assistive force required to tow the swimmer at a slightly higher known velocity. The mean values of the active drag obtained were similar to those previously reported (Male 95 & 83 N, Female 73 & 69 N in freestyle and butterfly). A graph of time against active drag for butterfly highlighted the propulsion and recovery phases. The within stroke drag fluctuations in freestyle were less than in butterfly. The active drag graph combined with synchronised video would enable the swimmer’s technical efficiency to be evaluated throughout the stroke cycle. This method could be used to identify aspects of the swimmer’s stroke that corresponded with changes in the swimmer’s active drag

    Portfolio pointers: Preparing and presenting high quality teaching portfolios

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    This goal of this project was to develop a set of guidelines for creating teaching portfolios for the Tertiary Teaching Excellence Awards or for other purposes. It includes key pointers to “getting started”, collecting evidence, interrogating practice, editing, and protecting the unique “voice” of the nominee and their student body. The guidelines consist of general principles and practical examples from both successful academic developers and award recipients and some examples from award-winning portfolios to illustrate good practice

    A KINETIC ANALYSIS AND RECOMMENDATIONS FOR ELITE SWIMMERS PERFORMING THE SPRINT START

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    The object of this project was to identify on block characteristics of superior grab starts and identify if these also applied to the track start. Six elite swimmers were selected for the study. The characteristic most closely observed in excellent off block starting ability for the grab start was peak power normalised to body mass. Average power and maximum horizontal propulsive force normalised to body mass were closely linked as was work output, but not as highly as the previous parameters. Horizontal velocity off the block was not a good predictor of off block ability as the angle at which the swimmer left the block played an important role in the outcome. Time off the block and first movement time were poor indicators of starting ability. Similar characteristics, but with completely different force and power profiles, were evident for swimmers that utilised a track start

    Diagnosis of an anaerobic pond treating temperate domestic wastewater: An alternative sludge strategy for small works

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    An anaerobic pond (AP) for treatment of temperate domestic wastewater has been studied as a small works sludge management strategy to challenge existing practice which comprises solids separation followed by open sludge storage, for up to 90 days. During the study, effluent temperature ranged between 0.1 °C and 21.1 °C. Soluble COD production was noted in the AP at effluent temperatures typically greater than 10 °C and was coincident with an increase in effluent volatile fatty acids (VFA) concentration, which is indicative of anaerobic degradation. Analysis from ports sited along the AP's length, demonstrated VFA to be primarily formed nearest the inlet where most solids deposition initially incurred, and confirmed the anaerobic reduction of sludge within this chamber. Importantly, the sludge accumulation rate was 0.06 m3 capita−1 y−1 which is in the range of APs operated at higher temperatures and suggests a de-sludge interval of 2.3–3.8 years, up to 10 times longer than current practice for small works. Coincident with the solids deposition profile, biogas production was predominantly noted in the initial AP section, though biogas production increased further along the AP's length following start-up. A statistically significant increase in mean biogas production of greater than an order of magnitude was measured between winters (t(n=19) = 5.52, P < 0.001) demonstrating continued acclimation. The maximum methane yield recorded was 2630 mgCH4 PE−1 d−1, approximately fifty times greater than estimated from sludge storage (57 mgCH4 PE−1 d−1). Anaerobic ponds at small works can therefore enable sludge reduction and longer sludge holding times than present thus offsetting tanker demand whilst reducing fugitive methane emissions currently associated with sludge storage, and based on the enhanced yield noted, could provide a viable opportunity for local energy generation
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