Effects of sulfonation process on thermal behavior and microstructure of sulfonated polysulfone membranes as a material for Proton Exchange Membrane (PEM)

This paper reports the effect of sulfonation processon thermal behavior and microstrucutre of sulfonated polysulfone membrane. Various degree of sulfonation reactin has been conducted and the sulfonated membranes were characterized by thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), x-ray diffraction (XRD) and scanning electron microscopy (SEM). Modifications of the origin polysulfone polymer resulted in an increment value of glass transition temperature (Tg) due to the introduction of sulfonic acid group to the polymer backbone. However, due to some hindrance such as trace amount of organic solvent left during solvent evaporation and high hydrophilicity of the produced sulfonated membranes resulted in decreasing values of Tg. The polymer membrane showed lower degradation temperature as a function of degree of sulfonation. From XRD analysis, it was found that the membrane shows slight crystalline behavior after the sulfonation reaction. Detail discussions and observation of the alteration in microstructure of the sulfonated membrane were supported by SEM micrograph

Experimental investigation of feedforward control schemes of a flexible robot manipulator system

This paper presents experimental investigations into the applications of feedforward control schemes for vibration control of a flexible manipulator system. Feedforward control schemes based on input shaping and filtering techniques are to be examined. A constrained planar single-link flexible manipulator is considered in this experimental work. An unshaped bang-bang torque input is used to determine the characteristic parameters of the system for design and evaluation of the input shaping control techniques. The input shapers and filtering techniques are designed based on the properties of the system. Simulation results of the response of the manipulator to the shaped and filtered inputs are presented in time and frequency domains. Performances of the shapers are examined in terms of level of vibration reduction and time response specifications. The effects of derivative order of the input shaper on the performance of the system are investigated. Finally, a comparative assessment of the control strategies is presented and discusse

Studying the Dynamical Properties of 20 Nearby Galaxy Clusters

Using SDSS-DR7, we construct a sample of 42382 galaxies with redshifts in the region of 20 galaxy clusters. Using two successive iterative methods, the adaptive kernel method and the spherical infall model, we obtained 3396 galaxies as members belonging to the studied sample. The 2D projected map for the distribution of the clusters members is introduced using the 2D adaptive kernel method to get the clusters centers. The cumulative surface number density profile for each cluster is fitted well with the generalized King model. The core radii of the clusters' sample are found to vary from 0.18 Mpc \mbox{h}^{-1} (A1459) to 0.47 Mpc \mbox{h}^{-1} (A2670) with mean value of 0.295 Mpc \mbox{h}^{-1}. The infall velocity profile is determined using two different models, Yahil approximation and Praton model. Yahil approximation is matched with the distribution of galaxies only in the outskirts (infall regions) of many clusters of the sample, while it is not matched with the distribution within the inner core of the clusters. Both Yahil approximation and Praton model are matched together in the infall region for about 9 clusters in the sample but they are completely unmatched for the clusters characterized by high central density. For these cluster, Yahil approximation is not matched with the distribution of galaxies, while Praton model can describe well the infall pattern of such clusters.Comment: 16 pages, 8 figure

Pregnant women’s satisfaction and comprehension level of information given during HIV Counseling and Testing for PMTCT in public health facilities in Addis Ababa

Background: In Ethiopia PMTCT services began in 2003, but only 0.8% of HIV infections among births to HIV positive mothers were averted in 2005/6 through PMTCT.Objective: To determine the pregnant women’s satisfaction and comprehension level of the information given during pre- and post- HIV counselling and testing for PMTCT in public health centers in Addis Ababa City.Method: A cross-sectional study was conducted on purposively selected 10 health centers in Addis Ababa from April to May 2008. Data were collected at exit points using a pre-tested structured questionnaire adapted from UNAIDS tools. Descriptive and analytic statistics were computed.Result: Of the 422 women interviewed, 314 (74.6%) had discussion on MTCT/PMTCT; and 287 (91.4%) of those 314 reported to have comprehended the information. Of the 196 third trimester mothers, 83 (42.3%) were counselled on infant feeding options; among whom 59 (71.1%) reported to have comprehended the explanations well. Two hundred eighty-eight (68.4%) of the 422 clients had held discussions on HIV/AIDS; and 261 (90.6%) reported that they had understood the discussions well. The odds of knowing why HCT is offered during pregnancy was higher among clients who spent 5-15 minutes on discussion with their counsellors [OR=2.1, 95%CI: 1.03, 4.24].Conclusion: About 3/4th of the ANC clients were covered with PMTCT counseling in the ANC and the vast majority of the women interviewed reported that they were satisfied with the counselling and counsellors’ interactions with them. However, when prompted at the exit points, 21% of the mothers didn’t know why they were offered HCT particularly during pregnancy. [Ethiop. J. Health Dev. 2011;25(2):126-134

Status of ANC-linked HIV counseling and testing as an intervention for PMTCT in public health facilities in Addis Ababa: quality of HIV counseling given to pregnant women for PMTCT

Background: A high quality of PMTCT is essential for success: done well, it will result in significant reduction in child mortality through decreased peri-natal and postnatal HIV transmission; done badly, it could lead to deaths, increased drug resistance, and poor infant feeding. Objective: the aim of this study was to assess the quality of antenatal–based HIV counseling and testing as an intervention for PMTCT at ten public Health Centers in Addis Ababa City. Methodology: a cross sectional study was conducted at purposively selected 10 health centers in Addis Ababa fromApril to May 2008. Methods included observations of counseling sessions, and interview of key informants at PMTCT sites. Data on counselors’ communication skills, duration and content of pre- and post test counseling was collected using a structured questionnaire adapted from UNAIDS tools. SPSS Version 15.0 was used to enter, clean, and analyzethe data. Results: A total of 66 (31 pre- and 35 post test) counselling sessions were observed. The mean duration of pre-test counselling was 5.37 minutes (+3.34) and that of post test was 3.0 minutes (+ 2.24). In 78.8% of the sessions, the counsellors gave clear and simple information to mothers; in 25.8% of the sessions, the mothers were not given the chance to freely consent or dissent for blood test. In the post test sessions, 42.9% of the mothers’ understanding of the meaning of their test results was not explored. Conclusions: The communication skill of the counselors was generally ‘satisfactory’. The majority of pre- and post test sessions included the basic information on HIV and PMTCT/MTCT. However, the discussions were unusually brief, rudimentary and lacked depth and coverage

Burns in Tanzania: Morbidity and Mortality, Causes and Risk Factors: A Review.

Burn injuries in low and middle income countries still remain a significant health problem, even though numbers of burn injuries in high income countries have decreased showing that such events are not "accidents" but are usually preventable. WHO states that the vast majority (over 95%) of fire-related burns occur in low and middle income countries. Burn injuries are a major cause of prolonged hospital stays, disfigurement, disability, and death in Africa Region. Evidence shows that prevention strategies can work. However prevention strategies need to be tailored to the specific environment taking into account local risk factors and available resources. An examination of the patterns and causes of burns should allow site specific recommendations for interventions. This literature review, specific to the United Republic of Tanzania, was conducted by researching PubMed, SafetyLit, and African Journals on Line data bases for primary sources using key words <Tanzania> plus <burns, suicide, homicide, injury mortality, injury morbidity>. Two sets of student data collected as part of Bachelor's degree final dissertations at Muhimbili University of Health and Allied Sciences were used. In all, twenty two primary sources were found. Risk factors for burn morbidity in Tanzania are: 1/ a young age, especially years 1-3, 2/ home environment, especially around cooking fires, 3/ epilepsy, during seizures, and 4/ perceived inevitability of the incident. It was expected that ground level cooking fires would be found to be a risk factor, but several studies have shown non-significant results about raised cooking fires, types of fuel used, and cooking appliances. Risk factors for burn mortality are: being male, between 20-30 years of age, and being punished for alleged thieving by community mobs. An important factor in reducing burn morbidity, especially in children, is to educate people that burns are preventable in most cases and that most burns occur in the home around cooking fires. Children need to be kept away from fires. Epileptics should be monitored for medication and kept away from cooking fires as well. Community members need to be encouraged to bring wrong doers to the police

Effect of seaweed physical condition for biogas production in an anaerobic digester

The increasing demand for environmental protection and renewable energy has made bioenergy technologies such as anaerobic digestion substantially attractive. The main objective of this study is to determine the biogas yield from the raw seaweed Eucheuma cottonii and waste products using anaerobic digestion, operated under different physical conditions. Seaweeds comprise of a thallus (leaf like) and sometimes a stem and a foot (holdfast). Seaweed has the potential to be developed into the raw and waste material for biogas due to higher growth rates, greater production yields, and higher carbon fixation rates than land crops. Seaweed has 4–39% carbohydrate content and a high moisture content with low lignin compared to other terrestrial plants, thus it is simpler to be degraded. The integration of the findings may be the key to make seaweed waste product that is more efficient and affordable to serve as a sustainable and renewable energy source. The study used 1.5,L anaerobic digesters for fresh and 3-month-old Eucheuma sp. evaluated at different stages by monitoring the pH, chemical oxygen demand, and biogas production. The study found that within 18,days, the anaerobic digestion of E. cottonii seaweed yielded 0.4–1 ml biogas/g seaweed with up to 56% methane content