Effect of various types and sizes of aggregate on selfcompacting concrete

Aggregates play important role in concrete; it serves as Structural fillers which are used in concrete production. Aggregate sizes, types and gradation are the most important factor when selecting aggregate. This study examines incorporating different sizes and types of coarse aggregate. Testing rheology and strength of self-compacting concrete mixes at varying sizes and different types of coarse aggregate. The various aggregate sizes used in the Various mixes are 10, 12.5 and 20mm, the types of aggregate used are granite, gravel and ceramic tiles and superplasticizer used is Conplast SP 430 with water cement ratio of 0.45. slump flow test, T50, L-box and V-funnel test were carried out on the various mix to determine the fresh properties of the concrete mix. The mechanical properties (compressive, flexural and split tensile strength test) were conducted on the mixes at different curing age (7, 21 and 28 days). The aggregate size 10mm and granite types had the highest slump flow for the fresh test. It was observed from the mechanical test 10mm and 12.5mm granite size had a higher strength than gravel and ceramic tiles

Effect of Superplasticizer on Workability and Properties of Self-Compacting Concrete

From recent issues of stability, particle suspension, particle segregation, flow characteristics and cohesiveness in concrete, Superplasticizer has played an important role in this part. This research examined the effect of superplasticizer on workability and properties of self-compacting concrete (SCC). Three types of superplasticizers Conplast SP 561, Conplast SP 430 and Conplast SP 264 at different percentages (0, 10, 20 and 30%) with the same water cement ratio of 0.3, with M30 grade of concrete. The workability slump, v-funnel and l-box the test carried out on fresh concrete. Compressive strength test was carried out on the hardened concrete. All mix were satisfactory but the mix with conplast SP 430 had better workability and strengt

Mitigating Turbulence-Induced Fading in Coherent FSO Links: An Adaptive Space-Time Code Approach

Free space optical communication systems have witnessed a significant rise in attention over the last half a decade owing largely to their enormous bandwidth and relative ease of deployment. Generally, free space optical communication systems differ in their detection mechanism as various detection mechanisms are being reported, including intensity modulation/direct detection FSO, differential FSO and coherent FSO. In this chapter, we explore the prospect of obtaining an optimally performing FSO system by harnessing the cutting-edge features of coherent FSO systems and the coding gain and diversity advantage offered by a four-state space-time trellis code (STTC) in order to combat turbulence-induced fading which has thus far beleaguered the performance of FSO systems. The initial outcomes of this technique are promising as a model for various visible light communication applications

Effect of Climate Change on Arable Crop Farmers Productivity in Ibarapa Centra Local Government Area of Oyo State Nigeria

The study was an analysis of the Effect of climate change on arable crop farmers’ productivity in ibarapa central local government of Oyo state, Nigeria.  Primary data were collected using structured interview guide, administered on 100 arable crop farmers using multistage sampling technique. Data collected were analyzed using descriptive statistics (frequency and percentage) and inferential (partial correlation) statistical tools. The result showed that the mean age was 47.6years while 97% were married. However 97.00% of the arable crop farmers reported to have had malaria attack occasionally within the last10 years and 83.00% in the last five years  while 64% reported malaria occurrence within the last one year.Majority (83.00%) of the respondent stated that erratic rainfall as compared to other causes  had more effect on their productivity while just a few (7.00%) of the respondent claimed that low heat was the cause of their low productivity. The hypothesis tested revealed that the socioeconomic characteristics of the arable crop farmers such as age (0.7490), sex (0.3200), household size (0.4580), income (0.5500) and educational status (0.3240) had significant positive relationship with their levels of productivity. It was recommended that the arable crop farmers should form farmers association to pool resources together to acquire irrigation gadgets so as to alleviate the problem of erratic nature of rainfall in the area and Nigerian Meteorological Agency (NIMET) should be more alive to her weather forecast responsibilities in the area of using diverse languages of the people in the Nigerian agricultural zones. Keywords:Climate Change, Arable crop, Farmers, Productivity

Potential use of coconut stem as reinforcement in concrete slab

The utilization of an economical, eco-friendly, renewable building material has gained the attention of researchers lately. The construction sector is responsible for depleting large quantities of non-renewable resources. This activity not only generates millions of tons of mineral waste but millions of tons of carbon dioxide gas emissions as well. Research is thus needed on building materials based on renewable resources such as vegetable fibres. Investigated was on the possible use of coconut stem strips as reinforcement in concrete paste. The coconut stem was cut into various lengths, diameter, treated and coated with gloss paint and coal tar. Various tests in accordance to standard were conducted to determine the performance of the coconut stem strips. Compressive strength test and impact load tests were carried out on the concrete slab specimens to satisfy the desire of incorporating coconut stem as reinforcement in concrete slab. The compressive strength was performed on a large number of concrete cubes; 3 cubes each for day 7, 14, 21 and 28. As regards the impact loads test, 13 slabs were cast, 3 slabs each containing steel, dried coconut stem strips, gloss painted coconut stem strips, coal tar coated coconut stem strips with varying dimensions of 16 � 15 mm, 20 � 15 mm and 25 � 15 mm and plain slab without reinforcement serving as control. As expected, the slab reinforced with steel showed better strength in the cured state; however, the 2% of the coconut stripes reinforcement treated with coal tar would serve as good as the conventional steel reinforcement for normal concrete. The coal tar can be used for low-bearing load structures such as lintel and pavement

Incorporation of Silica Fume and Metakaolin on Self Compacting Concrete

This study carried out an experimental design investigating the reaction of mineral admixtures on fresh and hardened properties of sustainable self compacting concrete (SCC). Silica fume (SF) and metakaolin (MK) were partially replaced by Portland cement at 5, 10, 15, 20 and 25% in varying proportions. The workability on the fresh concrete was examined and the strength performance. The water cement ratio of 0.38 was kept constant for all the samples tested. The compressive strength was measured at 7, 14, 21 and 28 curing days. The test results indicated that with the influence of 2% superplasticizer, the fresh concrete showed a satisfactory workability, decreased the segregation to resistance, ease of flowing ability with the addition of silica fume and metakaolin. It was concluded in this study that, the replacement with silica fume was found to have an early strength gain in the compressive strength of SCC samples and a decrease at varying dosages. However, 15% metakaolin was considered to be a suitable replacement with 49.08 MPa at 28days compared with the control mix.

DETERMINATION OF AFLATOXIN LEVELS IN COMMERCIAL POULTRY FEEDS SOLD IN SOME PARTS OF SOUTHWESTERN NIGERIA

Aflatoxin contamination of animal feeds is common and widely spread especially in the tropics due to        ubiquity of the producing fungi. This study was carried out to identify and quantify common moulds and        aflatoxin levels in commercial poultry feeds sold in four states of South Western, Nigeria. Twenty sam-        ples of poultry feeds, 5 from each state (Lagos, Ogun, Osun and Oyo) were bought from retailers. The        feed   samples   were   analysed   microbiologically   for   moulds   and   total   aflatoxins   using   Enzyme-linked                                                                              4            4         Immunosorbent   Assay   (ELISA).   Mould   count   ranged   between   1  x   10 and   8   x   10 cfu/g.   Common        moulds   isolated   were   Aspergillus   flavus,   A.  parasiticus,  A.   terreus,   A.  niger,  A.  oryzae,  Rhizopus        oryzae,  and Penicillium notatum.  Total aflatoxin levels ranged between 13.5 and 270 ug/kg. Maize        was the main ingredient in all feeds examined. This study highlights the need for routine surveillance.         Feed millers are encouraged to add fungal growth inhibitors or toxin binders to their feeds.&nbsp

Comparative Analysis of the Relationship between Budget Balance and Selected Macro Economic Variables in Nigeria and Ghana

The export is one of the most important macro economic variable that affects a country's budget balance. This study examines the comparative analysis of budget balance and selected macro economic variables in Nigeria and Ghana using the World Bank Development Indicators data from 1970-2012. The study through the Augmented Dickey Fuller (ADF)/ unit root test found that the variables used in the model are integrated of the order one while export and interest rate are integrated of the order zero. Using the Johansen co integration tests shows the presence of long run relationship between variables. The Error Correction Model (ECM) results suggest that export has a significant impact on budget balance in the short run and . The study therefore recommends that the competitiveness and stability of export should be given due consideration as this will increase economic growth through increased investment. Keywords: Export, Budget Balance, ADF, ECM, Nigeria, Ghana

Socio-Economic Benefits of Microgravity Research

Microgravity researches are conducted in low gravity environments. These low gravity environments can be achieved in a number of ways including parabolic aircraft flights, sounding rockets, drop towers, clinostat.  Gravity dominates everything on Earth, from the way life has developed to the way materials interact. The reduction of gravity causes significant changes in the chosen sample which could be cells, plants, micro-organisms and small samples from material sciences. The changes that occur as a result of the effect of microgravity have led to discoveries that have been found to be of socio-economic benefits. Socio-economic benefits involve benefits in wealth, health, economic, environment. Sustainable development in an economy includes economic growth, environmental protection and social equality. Space technology applications such as in microgravity stimulate economic growth and improve the quality of life of people, in this way, it is beneficial to mankind.  Overall, products manufactured in microgravity environments have key properties usually surpassing the best terrestrial counterparts. Commercially, these products have attractive features that facilitate marketing. This review considers the various benefits of microgravity research in life-sciences such as in microbiology, pharmacy, and medicine

Smart Grid Systems in Nigeria: Prospects, Issues, Challenges and Way Forward

The ability of the power system to deliver to its consumer electrical energy at an expected level of reliability is correlated with the economic development of a country. The Nigerian power system faces many challenges, varying from overdue infrastructure maintenance, obsolete tools and appliances, insufficient electricity supply, corruption, etc. A gradual shift from manual to smart digital technologies include; smart metering, distributed generation (renewable energy and microgrid), and management using Information and Communication Technology (ICT) tools. In response, research, investments, and upgrade to the power sector are fundamental. This paper discusses and analyses the various smart grid technologies utilised in the Nigerian power system with their effects, impacts, deployment, and integration into the traditional Nigerian power grid. Also discussed are issues and challenges of smart grid deployment and ways of mitigating these challenges