University of Nigeria, Nsukka

About: University of Nigeria, Nsukka is a education organization based out in Nsukka, Nigeria. It is known for research contribution in the topics: Population & Health care. The organization has 10211 authors who have published 13685 publications receiving 138922 citations.

The Effect of Relative Density and Confining Stress on Shear Properties of Sands with Varying Grading

Abstract: The research investigated the influence of grain size distribution on the shear behavior of sand specimen in loose, medium and dense states. The investigation aimed at understanding the extent or degree at which static shear strength of soil is affected by its density. A standard indicator (coefficient of uniformity) was used in constituting four (4) different sand specimens—narrowly graded (NAG), intermediately graded (ING), well graded (WG) and gap graded (GAG). Different normal stress values were applied during the testing program. The specimens were sheared using a ring shear apparatus until a residual value of shear stress was obtained. Result obtained from the analysis shows two remarkable stress paths. Medium dense to dense specimens show dilative stress path while loose (less dense) specimens show contractive stress path. At loose state, WG specimens show higher peak and residual shear strengths than poorly graded ones. Of importance was the fact that all the NAG specimens underwent complete liquefaction but WG specimens did not undergo complete liquefaction. This was interpreted as strong inter-particle contacts/forces binding the grains which enhanced high shear resistance. The research also showed that increase in relative density leads to higher shear strength, particle size distribution notwithstanding. Also, result of the analysis showed that WG specimens in medium-and dense states have higher peak but lower residual strength than ING and NAG specimens-this phenomenon was termed reverse behavior by the author(s). GAG specimens when sheared have the lowest peak and residual strength at any given value of relative density.

Growth retardation in homozygous sickle cell disease: Role of calorie intake and possible gender‐related differences

Abstract: To evaluate the possible role of inadequate food intake in the pathogenesis of the growth retardation of patients with sickle cell anemia, we determined the daily intake of calories and macronutrients and measured several anthropometric indices in 20 patients with sickle cell anemia aged 17-35 years and in 15 of their normal siblings of similar age. Compared to the control groups, the male patients, but not the females, had a significantly lower mean weight, body mass index, midarm circumference, and triceps and subscapular skinfold thicknesses. Also, while the male patients consumed significantly less total calories, proteins, carbohydrates, and fats per day than their control group, no difference was noted between the daily intake of calories or macronutrients in the female patients and their control group. However, when the intake of calories and macronutrients was corrected for body weight, there was no statistically significant difference between the intake of nutrients in the male patients and their control subjects or between the female patients and their control group. These results suggest a sex-related difference in the somatic growth of adolescent and adult patients with sickle cell anemia and also suggest that, although an inadequate food intake may be partly responsible for the impaired somatic growth in sickle cell anemia, other factors are also probably important.

Electricity Generation From a Compound Parabolic Concentrator Coupled to a Thermoelectric Module

Abstract: Generating electricity from the sun using a combination of a compound parabolic concentrator (CPC) and a thermoelectric module (TEM) has been studied. The system was modeled, analyzed, and tested. The model equations and the methodology used for the demonstration are presented and experimentally validated. The experimental setup comprised a manually fabricated CPC placed on a commercially available TEM. The results showed that the combination can generate and sustain enough power for a small appliance. It was also shown that there is enough dissipated heat from the system, which could be harnessed for additional uses. The cost is still high, about $35/Wp, but if credit is given for the thermal energy the initial cost goes down.

Rainfall intensity-duration-frequency analysis for Southeastern Nigeria

Abstract: Inadequate hydrologic data and the need for proper planning of water resources development have forced engineers to analyze available data more critically. This is particularly so in developing countries. The Intensity-Duration-Frequency (IDF) relationship is one of the most commonly used basis for water resources planning and development. This study analyzed rainfall data and characteristics for locations in seven states of Southeastern Nigeria. IDF curves were developed for these locations using two methods ( Graphical and Statistical ) and the results were compared. The locations are Onitsha in Anambra State, Enugu in Enugu State, Abakiliki in Ebonyi State, Umuahia in Abia State, Owerri in Imo State, Port Harcourt in Rivers State and Uyo in Akwa Ibom State. Break-point, short duration, rainfall data are not generally available in the historical records at the locations. Generalized accumulated rainfall patterns developed by USDA Soil Conservation Service were matched with rainfall data for the locations of study, and the advanced pattern had the best fit with the observed characteristics and was used to break down recorded daily totals into shorter duration rainfall data. The method of annual maxima series was used to select data sets for the rainfall analysis. In the statistical method, the Type I extreme-value distribution (Gumbel) was applied to the annual maximum series for each of the seven stations to estimate the relevant parameters of the IDF model. The non-parametric Kolmogorov-Smirnov test and the χ 2 test were used to confirm the appropriateness of the fitted distributions for the locations. IDF data developed from the graphical and statistical methods applied were very close for the lower return periods of two to ten years, but differ ed for higher return periods of 50 to 100 years. However, the difference is not significant at 5% level. The data developed by either of the methods will facilitate planning and design for water resources development in Southeastern Nigeria. Keywords: rainfall , intensity, water resources , hydrologic data Citation: Okonkwo G. I., and C. C. Mbajiorgu. Rainfall i ntensity- d uration- f requency a nalys i s for S outh e astern Nigeria . Agric Eng Int: CIGR Journal, 2010, 12(1): 22 - 30 .

Perceptions of the appropriate response to norm violation in 57 societies

Abstract: Norm enforcement may be important for resolving conflicts and promoting cooperation. However, little is known about how preferred responses to norm violations vary across cultures and across domains. In a preregistered study of 57 countries (using convenience samples of 22,863 students and non-students), we measured perceptions of the appropriateness of various responses to a violation of a cooperative norm and to atypical social behaviors. Our findings highlight both cultural universals and cultural variation. We find a universal negative relation between appropriateness ratings of norm violations and appropriateness ratings of responses in the form of confrontation, social ostracism and gossip. Moreover, we find the country variation in the appropriateness of sanctions to be consistent across different norm violations but not across different sanctions. Specifically, in those countries where use of physical confrontation and social ostracism is rated as less appropriate, gossip is rated as more appropriate.