Assessment of the physical characteristics and stormwater effluent quality of permeable pavement systems containing recycled materials

This paper evaluates the physical characteristics of two recycled materials and the pollutant removal efficiencies of four 0.2 m2 tanked permeable pavement rigs in the laboratory, that contained either natural aggregates or these recycled materials in the sub-base. The selected recycled materials were Crushed Concrete Aggregates (CCA) and Cement-bounded Expanded Polystyrene beads (C-EPS) whilst the natural aggregates were basalt and quartzite. Natural stormwater runoff was used as influent. Effluent was collected for analysis after 7–10 mins of discharge. Influent and effluent were analysed for pH, Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), Electroconductivity (EC), turbidity, Total Suspended Solids (TSS), Total Dissolved Solids (TDS), Nitrate-Nitrogen (NO3-N), reactive phosphorous (PO43-) and sulphates (SO42-). Both CCA and C-EPS had suitable physical properties for use as sub-base materials in PPS. However, C-EPS is recommended for use in pavements with light to no traffic because of its relatively low compressive strength. In terms of pollutant removal efficiencies, significant differences (p 0.05) were found with respect to TSS, turbidity, COD and NO3-N. Effluent from rigs containing CCA and C-EPS saw significant increases in pH, EC and TDS measurements whilst improvements in DO, TSS, turbidity, COD, PO43- and SO42- were observed. All mean values except pH were, however, within the Maximum Permissible Levels (MPLs) of water pollutants discharged into the environment according to the Trinidad and Tobago Environmental Management Authority (EMA) or the United States Environmental Protection Agency (US EPA). In this regard, the CCA and C-EPS performed satisfactorily as sub-base materials in the permeable pavement rigs. It is noted, however, that further analysis is recommended through leaching tests on the recycled materials

Barium Enema Reduction of Intussusception in a Developing Country

Objective: To determine the current success rate of barium enema reduction of intussusception and to investigate the factors affecting successful reduction. Design and Methods: All patients admitted to the Eric Williams Medical Sciences Complex during the 8-year period from January 1, 2000 to December 31, 2007 with a diagnosis of intussusception were included. Patients’ demographics, date and time of admission, clinical features, success of barium reduction, surgical findings and length of stay were recorded. The SPSS 12.0 programme was used for data analysis. Results: There were 65 cases of intussusception. Vomiting and rectal bleeding were the most common presenting symptoms (55, 85% / 49, 75%). Fifty-eight patients underwent barium enema reduction with 41.4% (24/58) having successful reduction. Factors which significantly increased the success rate included males older than 12 months, non-opioid analgesia or no analgesia and an admission to enema reduction time of less than 6 hours. Conclusion: The successful reduction rate is relatively low (41%). A higher index of suspicion is needed in order to make a timely diagnosis and institute appropriate treatment quickly. Keywords: Barium enema, enema reduction, intussusceptions "Reducción de la Intususcepción Mediante Enema de Bario en un País en Vías de Desarrollo" R Tota-Maharaj, B Rampersad, R Indalsingh RESUMEN Objetivo: Determinar la tasa de éxito actual de reducción de la intususcepción por edema de bario e investigar los factores que afectan la reducción exitosa. Plan y métodos: Todos los pacientes ingresados en el Complejo de Ciencias Médicas Eric Williams por el período de 8 años que va del 1ero de enero de 2000 al 31 de diciembre de 2007 con diagnóstico de intususcepción, fueron incluidos. Se registró toda la información relacionada con los datos demográficos de los pacientes, fecha y tiempo de ingreso, características clínicas, éxito de la reducción por bario, resultados quirúrgicos, y duración de la hospitalización. Se usó el programa SPSS 12.0 para el análisis de los datos. Resultados: Se produjeron 65 casos de intususcepción. Los vómitos y el sangramiento rectal fueron los síntomas presentes más comunes (55, 85%/49, 75%). A cincuenta y ocho pacientes se les practicó la reducción por enema de bario, logrando 41.4% (24/58) una reducción exitosa. Los factores que aumentaron la tasa de éxito de manera significativa fueron los varones con más de 12 meses, la analgesia no-opioide o ninguna analgesia, y un tiempo de ingreso para la reducción por enema, de menos de 6 horas. Conclusión: La tasa de reducción exitosa es relativamente baja (41%). Se requiere un índice más alto de sospecha para hacer un diagnóstico oportuno e iniciar un tratamiento apropiado rápidamente. Palabras claves: Enema de bario, reducción por enema, intususcepció

Economical Darrieus straight bladed vertical axis wind turbine for renewable energy applications

In remote and stand alone applications, the simple straight bladed Darrieus type vertical axis wind turbine is very practical due to its simple design and low cost of construction. It has the potential to compete effectively with the more widely used horizontal axis wind turbines. This project explores a Darrieus type vertical axis wind turbine, adapted for domestic electricity generation. Design, construction and modelling of a three-blade vertical axis wind turbine with 305 cm long blades, 55 cm chord length, which formed a symmetrical airfoil of National Advisory Committee for Aeronautics (NACA 0018) profile, was performed in this study to demonstrate how used materials can be recycled to produce an economically feasible Darrieus type vertical axis wind turbine that can be utilised to produce usable electrical power. The double multiple streamtube model was used to reproduce this turbine. Materials used were chosen for practicality, availability within the southern Caribbean islands of Trinidad and Tobago, in addition to their low cost. From the performance modelling and performance characteristics of the automotive alternator, it was observed from initial testing data that wind speeds of 3–5 m s−1 produced wind power up to 5400 W. The cost per watt of power generated was the lowest for this wind turbine ($0·54 W−1) when compared to other VAWT and can even compete on cost effectiveness with traditional horizontal axis wind turbines