Influence of Some Variable Parameters on Horizontal Elliptic Micro-Channels with Internal Longitudinal Fins

The study investigates the laminar flow and heat transfer characteristics in elliptic micro-channels of varying axis ratios and with internal longitudinal fins, operating in a region that is hydrodynamically and thermally fully developed; purposely to determine the effects of some salient fluid and geometry parameters such as Reynolds number, Prandtl number, aspect ratio ( and fin heights on flow pattern and rate of heat transfer. Numerical method using the finite difference technique was adopted for the solution. A code in Quick Basic was developed to generate the results. Results show that fin height of H=0.6 provided the optimum heat transfer enhancement for the configuration of e = 0, e= 0.433 and e=0.714; for e=0.866, fin height of H= 0.4 is tolerable. Result also show that Nusselt number increases with Reynolds number for all axis ratios investigated. However, at Re=200 a slight trough was observed in Nusselt number Versus Reynolds number relationship indicating a critical flow condition. It was also established that at , Nusselt number and bulk fluid temperature, are independent of fluid properties

Twelve-month observational study of children with cancer in 41 countries during the COVID-19 pandemic

Introduction Childhood cancer is a leading cause of death. It is unclear whether the COVID-19 pandemic has impacted childhood cancer mortality. In this study, we aimed to establish all-cause mortality rates for childhood cancers during the COVID-19 pandemic and determine the factors associated with mortality. Methods Prospective cohort study in 109 institutions in 41 countries. Inclusion criteria: children <18 years who were newly diagnosed with or undergoing active treatment for acute lymphoblastic leukaemia, non-Hodgkin's lymphoma, Hodgkin lymphoma, retinoblastoma, Wilms tumour, glioma, osteosarcoma, Ewing sarcoma, rhabdomyosarcoma, medulloblastoma and neuroblastoma. Of 2327 cases, 2118 patients were included in the study. The primary outcome measure was all-cause mortality at 30 days, 90 days and 12 months. Results All-cause mortality was 3.4% (n=71/2084) at 30-day follow-up, 5.7% (n=113/1969) at 90-day follow-up and 13.0% (n=206/1581) at 12-month follow-up. The median time from diagnosis to multidisciplinary team (MDT) plan was longest in low-income countries (7 days, IQR 3-11). Multivariable analysis revealed several factors associated with 12-month mortality, including low-income (OR 6.99 (95% CI 2.49 to 19.68); p<0.001), lower middle income (OR 3.32 (95% CI 1.96 to 5.61); p<0.001) and upper middle income (OR 3.49 (95% CI 2.02 to 6.03); p<0.001) country status and chemotherapy (OR 0.55 (95% CI 0.36 to 0.86); p=0.008) and immunotherapy (OR 0.27 (95% CI 0.08 to 0.91); p=0.035) within 30 days from MDT plan. Multivariable analysis revealed laboratory-confirmed SARS-CoV-2 infection (OR 5.33 (95% CI 1.19 to 23.84); p=0.029) was associated with 30-day mortality. Conclusions Children with cancer are more likely to die within 30 days if infected with SARS-CoV-2. However, timely treatment reduced odds of death. This report provides crucial information to balance the benefits of providing anticancer therapy against the risks of SARS-CoV-2 infection in children with cancer

Free Convective Flow of a Reacting Fluid between Vertical Porous Plates

This study investigates free convective flow between vertical porous plates. The energy and momentum equations which arise from the definitions of temperature and velocity are written in dimensionless forms. The resulting second order equations are solved to obtain expressions for the velocity, temperature, mass transfer skin friction, and rate of heat transfer.Keywords: Convective flow, reacting fluid, vertical porous plates

Cost-benefit analysis of hybrid wind-solar power generation by homer power optimization software

HOMER power optimization software for evaluation of design and performance of both off-grid and gridconnected power systems has been applied for cost-benefit analysis of a wind-solar hybrid power generation system. Comparison was also made with the cost per kilowatt of grid power supply. The hybrid system had a pay-back period of about thirty-three years. The central grid power was the least expensive option, but might not be available to most rural households far from the grid. Hence, the autonomous distributive system of hybrid power generation was advantageous

Determinants of Food Security among Rural Livestock Farmers in Southwestern Nigeria

This study examined the extent to which livestock production has contributed to food security of the rural households in Southwestern Nigeria. Multistage sampling procedure was used to select respondents for the study. Fifty percent of the states in Southwestern Nigeria and 30% of rural households in the selected local government areas were randomly selected resulting in a sample size of 306 respondents. Household food insecurity access scale (HFIAS), food insecurity scale was used to assess the food insecurity of the respondents. Data were analyzed using descriptive statistics while binomial regression was used to determine the determinants of food security at p = 0.05. Most respondents (76.1%) were males and married (83.7%), while about half (46.0%) of them completed secondary education. Mean age, household size and monthly income from livestock enterprises were 48.8 ± 12.8 years, 6.6 ± 3.2 and N45,068 ± 97,077, respectively. A large proportion (71.9%) practiced extensive system of livestock production. Sources of information (β = 5.304), income (β = 7.453) and constraints to livestock enterprises (β = 2.807) increased the odds of their food security. Policies that encouraged that promote diversification of income sources should be promoted to increase entrepreneurs’ income in order to improve food security situation of rural households.Keywords: Rural, Livestock Production, Food Security, Southwester

Development of a bench-scale fluidized bed combustor (FBC) for coal and biomas combustion.

The high technological level of equipment for combustion of fuels, as well as the necessity for rational and efficient use of non-renewable energy resources, has resulted demanding requirements that must be fulfilled by equipment for energy production, via combustion. These requirements form the characteristics of Fluidized bed Combustor (FBC). The objective of this work is to design and fabricate a Circulating FBC for the combustion of coal and biomass and present the design criteria considered in the combustion process. The Designed FBC was then tested by combusting coal (Lafia Obi) and biomass (coconut shell) using the relevant ASTM guidelines. For coal combustion, the characteristic quantities measured from the bench-scale fluidized bed combustion include a mean NOx emission of 455.35, 376.69, 323.35 and 277.35 ppm for a coal feed size of 10, 15, 20 and 25 mm respectively. NOx emission from the combustion of coconut shell in fluidized bed is low and further reduced by the introduction of secondary air. Secondary air increases the recoverable energy level from this biomass, while average CO emission was 13,080 16,620 17,040 and 19,140 ppm for a coal feed size of 10, 15, 20 and 25mm. The temperature in the fluidized bed at ≥ 1100oC was sustained.Keywords: Combustion emissions; fluidized-bed combustion; Design; Lafia-Obi Coal Biomass; Temperature

Neuro-Opthalmic Manifestations in a Patient With Hodgkin Disease: A Case Report

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