Effect of Batching Methods on the fresh and hardened properties of Concrete

This paper investigated the effect of batching by mass and volume on concrete’s compressive strength and workability. Influence of mix proportion at five levels and various water-cement ratios were also studied. All samples were cured by complete immersion in water and tested up to 28 days. The results indicated higher workabilities for concrete batched by mass than concrete batched by volume at all w/c ratios and mix proportions investigated. The workability increased with increase in w/c ratios in both methods. The compressive strength results showed that for rich structural mixes (1:1:2 and 1:1.5:3), concrete batched by mass had 20 % and 6 % strength increases respectively over the concrete batched by volume. Ordinary structural mix (1:2:4) had 14 % increase while non-structural mixes (1:3:6 and 1:4:8) had 8 % and 6 % increases respectively. In all cases, concrete batched by mass had better fresh and hardened properties of concrete

Occurrence and Environmental Implications of Calcareous Nannofossils in Surface Sediments of the Western Gulf of Guinea: off Lagos Coast, South-western Nigeria

The application of calcareous nannofossils in oil exploration, and environmental studies is playing an increasingly important role all over the world. Most recent researches on this subject area in Nigeria are confined/restricted to the oil producing Niger Delta leaving most other areas untouched. This however limits nannofossils’ application in biostratigraphic and paleoenvironmental interpretation of non oil producing areas within the country. Before now, nannofossils occurrence and application have not been documented in the surface sediments of Nigeria. Consequently, calcareous nannofossils have been investigated in thirteen (13) surface sediments samples of the littoral area from the continental shelf of western Gulf of Guinea, off Lagos coast. Primarily, this research was aimed at determining the occurrence (and or non occurrence), and relative abundance of nannofossils in surface sediments of the area with which the age of the sediments, paleoenvironment and paleoecological condition(s) could be determined.The samples were collected with the aid of grab sampler, allowed to dry and subjected to detailed lithologic description. Furthermore, the samples were subjected to nannofossils analysis by standard method of preparation. Both qualitative and quantitative analysis was done using the high power Olympus Transmitted Light Microscope (TLM). The occurrence of nannofossils has been established in the study area (littoral area of the western Gulf of Guinea). Most of the sediments are poorly consolidated, fine to coarse grained sand with little amount of clay ant silt fractions that yielded Pliocene to Recent nannofossils (mainly Pleistocene). A total population of 1132 belonging to five different genera (Calcidiscus, Ceratolithus, Gephyrocapsa, Helicosphera and Reticulofenestra) and seven species were found in the studied samples with Gephyrocapsa caribbeanica being the most abundant (followed by Gephyrocapsa oceanica of a little lower abundance). The species indicate a truly shallow marine environment within recent sediment accumulation. Keywords: Surface sediments, littoral, calcareous nannofossils, Gulf of Guinea, Lagos, Nigeria, biostratigraphy, paleoenvironment, paleoecology, lithologic

Antiulcerogenic activity of ethanolic leaf extract of Lasianthera africana

The effect of ethanolic leaf extract of Lasianthera africana on experimentally induced ulcer was studied in rats. The extract (1000 – 3000mg/kg) inhibited ethanol-induced, indomethacin – induced and reserpine –induced ulcer models in a dose dependent fashion. The various degrees of inhibitions were statistically significant (

A Gamma Spectrometeric Analysis and Radium Equivalent Activity Index of Water in Abak, Nigeria: A Baseline Survey

This study evaluated the concentration of radionuclides and radiation hazard indices for water with the use of gamma spectrometer in 10 different communities of Abak Local Government Area of Akwa Ibom State, Nigeria to serve as baseline data on the radiological status of the area. The results show that the commonly occurring radionuclides are not uniformly distributed in the water. The mean activity concentration of 40K, 238U and 232Th in the samples were estimated to be 105.46±8.16 Bq/l, 13.02±3.13 Bq/l and 2.44±0.21; Bq/l respectively. These values are well below internationally determined permissible exposure limits. The hazard indices radium equivalent activity, absorbed dose rate, effective dose rate, external and internal hazard indices had mean values of 24.6±4.06 Bq/l, 11.9±1.92 nGy/h, 0.02±0.002mSv/yr, 0.07±0.01 and 0.1±0.02 respectively.The computed hazard indices are all below the recommended standards. Therefore the water at the present time poses no radiological health threat to the populace. Keywords: Radionuclide concentration, radium equivalent, absorbed dose rate, internal hazard inde

Baseline Radionuclide Distribution Patterns in Soil and Radiation Hazard Indices for Abak, Nigeria

A gamma spectroscopy analysis for the naturally occurring radionuclides 226Ra, 232Th and 40K has been carried out for soil samples collected from communities in Abak Local Government Area of Akwa Ibom State to determine the concentration and distribution patterns of these radionuclides in the study area and to assess the possible radiological risks from the soil. The activity concentration of the samples range from 14.80±1.16Bq/kg to 150.20±11.47Bq/kg with a mean value of 98.709±7.693Bq/kg for 40K; from 14.52±3.49Bq/kg to 42.04±8.59Bq/kg for 238U with a mean of 24.826±5.425Bq/kg and from 3.05±0.27Bq/kg to 7.00±0.58Bq/kg with a mean of 5.172±0.31Bq/kg for 232Th. These values are within international regulatory standards. Assessment of the radiation hazard levels for the area gave values of 18.789±3.102nGy/h for absorbed dose, 0.3±0.05Bq/kg for representative level index, 39.82±6.65Bq/kg for radium equivalent, 0.11±0.02 for external hazard index, 0.18±0.032 for internal hazard index and 0.023±0.004mS/yr for effective dose rate. These indices are much lower than the ICRP permissible limits for soil showing that the soil of the study area poses no radiological threats to the public. Keywords: Radionuclide concentration, radiation hazard index, radium equivalent, internal hazard inde

Protein quality and digestibility of different parts (spathe and spadix) of Colocasia esculenta var. antiquorum flower

A rat growth and balance study was conducted to determine the protein quality and digestibility of the cooked spathe and spadix. Twenty-four (24) weanling male wistar rats were distributed in four groups of six elements. Test groups received respectively spathe- based, spadix-based and spadix + spathe-based diets. Each protein product was fed as the sole source of 10% dietary protein. The evaluated biological parameters were protein efficiency ratio (PER), net protein ratio (NPR) and true protein digestibility (TPD). The cooked spadix contained higher values of crude lipid (10.8% DM), crude protein (18.73% DM), and crude fibre (34.47% DM) while spathe had higher values of crude ash (9.26% DM), cellulose (8.20% DM), phytate (0.06 mg/100 g DM), cyanide (0.25 mg/100 g DM) and total oxalate (880.0 mg/100 g DM). Spathe showed significantly (p 0.05) between the TPD of spadix and spadix + spathe mixture. The presence of higher levels of cellulose, phytate and hydrocyanide in spathe could have been responsible for the lower protein digestibility and quality observed.Keywords: Colocosia esculenta, cocoyam, cooked spadix, cooked spathe, PER, NPR, TPD

Marital Satisfaction, Age And Alcohol Use During Pregnancy: An Empirical Study Of Pregnant Women In Uyo Metropolis, Nigeria

A convenient sampling technique was used to draw a sample of 110 pregnant women reporting for antenatal clinical checks in both private and public medical facilities in Uyo, Nigeria to investigate marital satisfaction and age as predictors of alcohol use during pregnancy. Kansas Marital Satisfaction Scale was used in dichotomizing respondents into satisfied and dissatisfied pregnant women in marriage, while an item in Alcohol Use Disorder Identification Test (AUDIT) delineated our cohorts into users and non-users of alcohol. A 2x2 factorial design was adopted as regards the plan of the study while a 2-way analysis of variance was used for the analysis of data collected. Results confirmed the first hypothesis which predicted that pregnant women who are satisfied in their marriages would report less alcohol use than their dissatisfied counterparts {F (1, 104) = 4.70; p < .05}. Findings also confirmed our second hypothesis which stated that pregnant women who are younger would report more alcohol use than their elderly counterparts {F (5, 104) = 11.833; p, <.05}. Discussion of findings centered on the theories of learning which formed the nucleus of this paper and it was recommended that intervention would benefit from effective and affordable psychological counseling and treatment services for women exposed to harmful and/or hazardous alcohol use predicated by marital distress, violence, depression as well as those with limited coping skills

A circuit model for defective bilayer graphene transistors

This paper investigates the behaviour of a defective single-gate bilayer graphene transistor. Point defects were introduced into pristine graphene crystal structure using a tightly focused helium ion beam. The transfer characteristics of the exposed transistors were measured ex-situ for different defect concentrations. The channel peak resistance increased with increasing defect concentration whilst the on–off ratio showed a decreasing trend for both electrons and holes. To understand the electrical behaviour of the transistors, a circuit model for bilayer graphene is developed which shows a very good agreement when validated against experimental data. The model allowed parameter extraction of bilayer transistor and can be implemented in circuit level simulators.<br/

An Assessment of the Effectiveness of Open Market Operations Instrument of Monetary Policy Management in Nigeria

This study empirically examined the effectiveness of Open Market Operations (OMO) instrument of monetary policy management in Nigeria. In doing this, the study adopted the monetarist theory as the basis for measuring the effectiveness of OMO instrument of monetary policy management in Nigeria. The investigation was carried out using the Ordinary Least Squares (OLS) method of estimation. Unit Root and Co-integration tests were performed on all the variables and the results revealed that the variables have long run relationship and are suitable for OLS estimation. The empirical results indicated a significant relationship between monetary policy instruments such as open market operations, required reserve and monetary policy rate with broad money supply which is the proximate target for monetary policy management. This implies that Open Market Operations has been an effective instrument of monetary policy management in Nigeria. The study further showed that monetary policy rate could serve as a veritable instrument for the control of money supply and effective monetary policy management in the economy. It is recommended, among others, that the CBN should review periodically the performance of monetary policy with a view to enhancing the effectiveness of monetary policy instruments in order to achieve macroeconomic stability. Keywords: OMO, Monetary policy effectiveness, Macroeconomic stability, Nigeria

Serological Survey of Dengue Virus Immunoglobulin M Among Febrile Patients in Kaduna Metropolis, Nigeria

The purposes of this research were to determine the prevalence of dengue virus in the study population, to determine the relationship between the occurrence of dengue virus IgM and potential risk factors and to determine the association between the occurrence of dengue virus and some symptoms. In this study, blood specimen were collected from 340 subjects with febrile complaints attending hospitals in Kaduna metropolis, Nigeria and who gave their consent to participate. Serological determination of dengue virus IgM was carried out using enzyme linked immunosorbent assay technique. Structured questionnaires were also administered to obtain data on demographic, risk factors,  and symptoms of illness. A total of 6 subjects were positive for dengue virus IgM giving a prevalence of 1.8%. There was no statistically significant association between the occurrence of dengue virus IgM and potential risk factors, demographic factors and symptoms of the illness. The occurrence of dengue virus in the study population was confirmed