Characteristics of concrete produced with burnt clay as coarse aggregate

Aggregate is the principal ingredient for concrete, and studies have predicted that excessive use of it would lead to insufficient quantity for future large constructions. This study investigate the use of burnt clay as alternative aggregates for concrete production. First clay was exposed to elevated temperature in the range of 1200 – 6000 C. Thereafter 3 sets of burnt clay aggregate were prepared then they were subjected to tests to determine the specific gravity, moisture content, water absorption, bulk density, impact value and crushing value test. These aggregates were subjected to compressive strength, impact value and crushing value tests. Result showed that the specific gravity of these aggregates exposed to between 600-1200oC, were between 2.11- 2.43. Whereas the bulk densities were between 973.7-1012 kg/m3 for burnt clay aggregates exposed to between 600 -1200oC. The moisture content of the burnt clay aggregates were in the range 1.749-1.833; Water absorption for the three sets of burnt clay aggregates was between 8.303-8.378 for clay aggregates heated to a range of 600-1200oC. The compressive strength for the three types of 100mm concrete cubes produced using the burnt clay aggregates after 28 days of curing, were between 10-11.2 N/mm2.While the compressive strength after 56days of curing, were between 13.20- 17.40N/mm2 for concrete produced with burnt clay aggregates subjected to elevated temperatures of 600-1200oC. The impact and crushing values of the crushed burnt clay aggregates ranges from 14- 33%. It was concluded that there is no significant difference between the quality of concrete produced with burnt clay aggregate and the conventional concrete (control sample). Hence, study recommended the use of burnt clay aggregate and durability properties of concrete be investigated.Keywords: Coarse Aggregates, Properties, Concrete, Burnt Clay, Water Absorptio

Result of 2004 extended trypanosomosis survey of ruminants at Kachia Grazing Reserve, North Central Nigeria

Tsetse fly and trypanosome prevalence in ruminants were estimated in April and August, peak months of the dry and rainy seasons in the Kachia Grazing Reserve (KGR) of Kaduna State, North Central Nigeria. This study was subsequent to reports of seasonal outmigration of semi nomadic Fulani from the grazing reserve due to death of cattle from trypanosomosis. Result of blood samples showed an overall parasitological infection rate of 17.4%. Infection rates in cattle, sheep and goats were, 18.6%, 9.5% and 5.1% respectively. Over all higher infection rate in the rainy season was attributed to abundance of tsetse and other hematophagus flies. Infection rate in younger animals (21.9%) was higher compared to those of older animals (16.5%). Trypanosoma vivax was the dominant infecting trypanosome specie followed by T. congolense and T. brucei.It was concluded that tsetse fly and trypanosomosis constituted dual plagues limiting economic livestock production and settling of the pastoralists in the grazing reserve. This warrants application of sustainable integrated control measures to enhance utilization of abundant fodder at the reserve.Key words: Kachia grazing reserve, trypanosomosis, ruminants, infection rates, Nigeria. Resultat de l'enquete de trypanosomose extension de 2004 des ruminants a la reserve de piscine Kachia, Nigeria Centrale du NordLa prévalence de la mouche tsé-tsé et du trypanosome chez les ruminants a été estimée en avril et août, les mois de pointe des saisons secanes et pluvieuses dans la réserve de pâturage de Kachia (KGR) de l'État de Kaduna, dans le nord du centre du Nigeria. Cette étude a été postérieure à des rapports d'émigration saisonnière de Fulani semi-nomades provenant de la réserve de pâturage en raison de la mort de bovins de la trypanosomose. Le résultat des échantillons de sang a montré un taux global d'infection parasitaire de 17,4%. Les taux d'infection chez les bovins, les ovins et les chèvres étaient respectivement de 18,6%, 9,5% et 5,1%. Le taux d'infection plus élevé pendant la saison des pluies a été attribué à l'abondance de mouches tsé-tsé et d'autres mouches hématophobes. Le taux d'infection chez les animaux plus jeunes (21,9%) était plus élevé par rapport à ceux des animaux plus âgés (16,5%). Trypanosoma vivax était le trypanosome infectant dominant suivi de T. congolense et T. brucei.On a conclu que la mouche tsé-tsé et la trypanosomose constituaient des fléaux doubles limitant la production d'élevage économique et la colonisation des pasteurs dans la réserve de pâturage. Cela justifie l'application de mesures de contrôle intégrées durables pour améliorer l'utilisation de fourrages abondants dans la réserve.Mots clés: réserve de pâturage de Kachia, trypanosomose, ruminants, taux d'infection, Nigeri

Stability analysis of maize cultivars adapted to tropical environments using AMMI analysis

Genotype × environment interactions complicate selection of superior genotypes for narrow and wide adaptation. Eighteen tropically-adapted maize cultivars were evaluated at six locations in Nigeria for 2 yrs to (i) identify superior and stable cultivars across environments and (ii) assess relationships among test environments. Environment and genotype × environment interactions (GEI) were significant (P −1 for TZL COMP4 C3 DT C2 with an average of 2555 kg ha−1. Cultivar DT SYN2-Y had the least additive main effect and multiplicative interaction (AMMI) stability value of 7.4 and hence the most stable but low-yielding across environments. AMMI biplot explained 90.5% and classified cultivars and environments into four groups each. IWD C3 SYN F3 was identified as the high-yielding and stable cultivar across environments. ZA15, ZA14, BK14, BK15 and IL15 had environment mean above the grand mean, while BG14, BG15, LE14, LE15, IL14, LA14 and LA15 had mean below the grand mean. ZA, BK, BG, LE and LA were found to be consistent in ranking the maize cultivars. However, Zaria, Birnin Kudu, and Ilorin were identified as the best test locations and could be used for selecting the superior maize cultivars. The identified high-yielding and stable cultivar could be further tested and promoted for adoption to contribute to food insecurity in Nigeria

Maize research at IAR Samaru

Maize (Zea mays L) research at the Institute for Agricultural Research (IAR), Samaru was initiated in the 1950s with the goal of developing adapted high yielding varieties and hybrids. Germplasm materials were collected from local sources as well as from different countries, including Columbia, Kenya, Mexico and the US' By the 1960s. IAR Samaru was actively participating in the National cooperative Trials, the West African Maize Variety Trials of the OAU-STRC Joint Project as well as the East African Maize Variety Trial coordinated by the East African Agricultural and Forestry Research organization (EAAFRO). Kitale, Kenya. By 197 6,a total of nine new open- pollinated varieties had been developed and released to farmers' The new maize technology packages developed gave up to 98% higher grain yield than the farmers traditional methods of production. In the 1990s, collaborative research continued under the west and Central African Collaborative Maize Research Network (WECAMAN) and the sasakawa Global20006G-2000) which, in partnership with IAR, disseminated new maize technologies to Nigerian farmers. In 2001, three new varieties developed and tested in collaboration With IITA-WECAMAN were registered and released to Nigerian farmers. Recently, Quality Protein Maize (QPM) trials were initiated in collaboration with lITA-WECAMAN.SG-2000, and CIMMYT and promising results have been obtained. The Institute continues to collaborate with national and international research organizations in maize improvement. The five decades of collaborative maize research at Samaru have contributed to increased land area under maize, increased grain yield, and increased income to maize farmer.La recherche sur le mais i Samaru a ete initi€e dans les ann6es 50avec le proiet d'am6lioration varietale centre sur le d6veloppementd'hybrides et de vari6tes adapt€s b hauts rendements' Les ressourcesg6n6tiques comprenaient du matdriel de source locale ainsi que desintroductions de diff6rents pays incluant la Columbie, le Kenya, le Mexique et les USA. Dans les ann6es 60, l'lAR i samaru a participeaux essais nationaux de collaboration, au proiet corrioint OAU-STRCdes essais vari6taux en Afrique de l'ouest ainsi qu'aux essais vari6tauxde mais pour l'Afrique de l'est, coordonn6s par l'organisatiorr derecherche en Agriculture et en foresterie de l'Afrique de l'est bas6ei Kitaty, Kenya. En 1976, un total de neuf nouvelles vari6tes ipollinisation libre a ete d6veloppe et vulgarise auprds des agriculteurs.Pendant les ann6es 80, les variet6s lrybrides d6veloppees par l'llTA encollaboration avec des chercheurs nationaux ont 6t6 homologu6es etcommercialisees par des entreprises privees de semences. Les nouveauxpaquets technologiques d6velopp6s dorrnaient iusqu'i 98 pour centen rendement grain plus eleve que les m6thodes traditionnelles cleproduction des agriculteurs. Dans les ann€es 90, l'lAR i samaru enpartenariat avec le Reseau de recherche sur le mais pour l'Afrique del'ouest et du centre OVECAMAN) et avec Sasakawa Global 2000, ontcontinue la recherche collaborative avec la promotion de nouvellestechnologies maisicoles auprEs des agricr-rlteurs Nigerians. En 2001,trois nouvelles vari6t6s developpdes et test6es en collaborationavec |'TA-WECAMAN ont et6 honrologu6es et vulgarisdes auprdsdes agriculteurs Nig€rians. Recemment, des essais de mais richesen proteines de qualit6 ont 6t€ inities en collaboration avec l'llTA-WECAMAN, SG2000 et le CIMMYT et des resultats prometteursont et6 obtenus. L'institut continue ) cooperer avec les organisationsde recherche internationale et nationale pour l'amelioration vari€taledu mais. L'impact des cinq d6cennies de recherche collaborative hSamaru a induit l'accroissement des superficies emblavees en mais,l'augmentation des rendements grains et l'augmentation des revenusdes agriculteurs qui cultivent le mais