Experimental study of the hydrodynamic behaviour of slug flow in a vertical riser

This paper presents an investigation of the hydrodynamics of slug flow in a vertical 67 mm internal diameter riser. The slug flow regime was generated using a multiphase air–silicone oil mixture over a range of gas (0.42<USG<1.35 m/s) and liquid (0.05<USL<0.38 m/s) superficial velocities. Electrical capacitance tomography (ECT) was used to determine: the velocities of the Taylor bubbles and liquid slugs, the slug frequencies, the lengths of Taylor bubbles and the liquid slugs, the void fractions within the Taylor bubbles and liquid slugs and the liquid film thicknesses. A differential pressure transducer was used to measure the pressure drops along the length of the riser. It was found that the translational velocity of a Taylor bubble (the structure velocity) was strongly dependent on the mixture superficial velocity. As the gas superficial velocity, was increased, the void fraction and the lengths of the liquid slugs and the Taylor bubbles were observed to increase. The increase in gas superficial velocity causes an increase in the frictional pressure drop within the pipe, whilst the total pressure drop (which is a sum of the hydrostatic and frictional pressure drop) along the length of the riser decreases. In addition, the frequencies of the liquid slugs were observed to increase as the liquid superficial velocity increases, but to be weakly dependant on the gas superficial velocity. The manual counting method for the determination of slug frequency was found to be in good agreement with the power spectral density (PSD) computed method

DOI: 10.5897/JSSEM12.068 ISSN 2141-2391 ©2013 Academic Journals Full Length Research Paper Nematode pests of plantain: A case study of Ashanti and Brong Ahafo regions of Ghana

A survey of plantain farms was conducted in April 2012 at four locations in two districts of Ghana. The purpose was to identify plant parasitic nematodes (PPN) associated with plantain production in Ghana. The locations were Adomakokrom and Kenyasi in the Brong Ahafo, Adanwomase and Mpobi in the Ashanti region. Demographic and sociological data of farmers, plantain root lesion scores, PPN populations per 200 cm 3 soil and 5 g plantain roots were analyzed. Nematode damage to root at Adomakokrom, Adanwomase, Mpobi and Kenyasi were 50, 75, 75 and 50%, respectively. Five nematode species were recovered from the rhizosphere of plantain. The nematodes were in the order of importance; Pratylenchus coffeae, Meloidogyne spp., Rotylenchulus reniformis, Radopholus similis and Helicotylenchus multicintus. High populations of P. coffeae (803/200 cm 3), H. multicintus (292/200 cm 3) and R. reniformis (343/200 cm 3) were extracted from soil samples at Adomakokrom, Adanwomase and Adanwomase respectively. Four parasitic nematodes; Meloidogyne spp., P. coffeae, R. reniformis and R. similis were extracted from plantain roots. Root populations were higher compared with soil samples. For sustainable plantain production in Ghana, an efficient management option must be devised. Key words: Ghana, integrated pest management, Musa spp., plant parasitic nematodes

Health system barriers influencing timely breast cancer diagnosis and treatment among women in low and middle-income Asian countries: evidence from a mixed-methods systematic review.

Globally, breast cancer is the most common cancer type and the leading cause of cancer mortality among women in developing countries. A high prevalence of late breast cancer diagnosis and treatment has been reported predominantly in Low- and Middle-Income Countries (LMICs), including those in Asia. Thus, this study utilized a mixed-methods systematic review to synthesize the health system barriers influencing timely breast cancer diagnosis and treatment among women in Asian countries. We systematically searched five electronic databases for studies published in English from 2012 to 2022 on health system barriers that influence timely breast cancer diagnosis and treatment among women in Asian countries. The review was conducted per the methodology for systematic reviews and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, while health system barriers were extracted and classified based on the World Health Organization (WHO)'s Health Systems Framework. The mixed-methods appraisal tool was used to assess the methodological quality of the included studies. Twenty-six studies were included in this review. Fifteen studies were quantitative, nine studies were qualitative, and two studies used a mixed-methods approach. These studies were conducted across ten countries in Asia. This review identified health systems barriers that influence timely breast cancer diagnosis and treatment. The factors were categorized under the following: (1) delivery of health services (2) health workforce (3) financing for health (4) health information system and (5) essential medicines and technology. Delivery of health care (low quality of health care) was the most occurring barrier followed by the health workforce (unavailability of physicians), whilst health information systems were identified as the least barrier. This study concluded that health system factors such as geographical accessibility to treatment, misdiagnosis, and long waiting times at health facilities were major barriers to early breast cancer diagnosis and treatment among Asian women in LMICs. Eliminating these barriers will require deliberate health system strengthening, such as improving training for the health workforce and establishing more healthcare facilities. [Abstract copyright: © 2022. The Author(s).

Effects of nutrient addition and soil drainage on germination of N-fixing and non-N-fixing tropical dry forest tree species

To develop generalised predictions regarding the effects of atmospheric nitrogen (N) and phosphorus (P) deposition on vegetation communities, it is necessary to account for the impacts of increased nutrient availability on the early life history stages of plants. Additionally, it is important to determine if these responses (a) differ between plant functional groups and (b) are modulated by soil drainage, which may affect the persistence of added nutrients. We experimentally assessed seed germination responses (germination proportion and germination energy, i.e. time to germination) of commonly occurring N-fixing and non-N-fixing tropical dry forest tree species found in India to simulated N and P deposition in well-drained soils, as well as soils with impeded drainage. When soils were not allowed to drain, germination proportion declined with nutrient addition, while germination energy remained unchanged. Stronger declines in germination proportion were observed for N-fixing species. In free-draining soils, nutrient addition did not affect germination proportion in either functional group. However, we detected a trend of delayed germination with nutrient addition, especially in N-fixers. Our results suggest that nutrient deposition can lead to potential shifts in functional dominance and tree community composition of tropical dry forests in the long term through its effects on early life stages of trees, although the mechanisms underlying the observed germination responses remain unclear. Further, such effects are likely to be spatially variable across the geographic range in which tropical dry forests occur depending on soil drainage properties

Prevalence of refractive errors among junior high school students in the Ejisu Juaben municipality of Ghana

Among school children, uncorrected refractive errors have a considerable impact on their participation and learning in class. The aim of this study was to assess the prevalence of refractive error among students in the Ejisu-Juabeng Municipality of Ghana. A survey with multi-stage sampling was undertaken. We interviewed 504 students aged 12-17 years and examined them for refractive errors. The prevalence of refractive errors among those with and without refractive error was compared by means of the chi-square test. Logistic regression analysis using refractive error as the dependent variable and adjusting for risk factors were performed. The overall prevalence rate of refractive errors was 7.5%. Out of the number of children with refractive errors, 39.5% had astigmatism, 31.6% had hyperopia and 28.9% had myopia. The prevalence rate was significantly higher among urban compared with rural students. Astigmatic refractive errors consists of with–the–rule (WTR) astigmatism 66.7%, against–the–rule (ATR) astigmatism 26.7% and oblique astigmatism (OBL) 6.6%. WTR and ATR astigmatism were more common in females than males. Multivariate logistic regression models showed no substantial confounding effects between near work, sex, and residence, suggesting that each covariate has an independent association with refractive error. In conclusion, near work, sex and high parental education level are factors contributing to refractive errors. Children in urban areas are at higher risk compared with their rural counterparts. We suggest that an efficient pre-school vision examination must be made part of the admission policy of all schools in Ghana.Keywords: Prevalence, refractive error, students, visual impairment, Ejisu-Juaben Municipalit

The Use of Computers and Internet as Supplementary Source of Educational Material: A Case Study of the Senior

Abstract This study was conducted to assess the computer and Internet usage as supplementary educational material to enhance quality education; help improve educational management and planning; how students use the computers and internet to facilitate their learning; how teachers in the Tema Senior High Schools use the computers and Internet to teach and guide students. Stratified sampling method was used to select students and teachers. The results showed that a significantly high percentage of respondent teachers (92%) were computer literate and 78% of respondent students also had basic knowledge in computer. However, less than 15% of these teachers used the internet as an innovative way of improving teaching and learning. Over 30% of the teachers used the computer mainly for research work. Less than 40% of student respondents used the computer and the Internet facility for entertainment, whereas less than 25% used it for research and learning. Less than 40% of respondent students used the Internet for e-mail and browsing. It was revealed that Internet and computers have helped students to achieve new things such as finishing assignments, solving problems, learning history of other countries, improving typing skills, and chatting with friends. There is no clear interaction between teachers and students through the use of Internet facilities. The Internet was not used for guidance. Despite the limited use of computers by teachers in their teaching, many agree that the computer has changed the way students learn. One fourth of teachers have received some form of training in the use of computers, with quite minimal training in the pedagogical integration of ICT. It appears that integration of ICT in Ghanaian school systems is a major step in promoting innovation