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Search Results: 1 - 10 of 12446 matches for " Christopher Mbaringong Agyingi "
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Characterization of Alluvial Gold Bearing Sediments of Betare Oya District-East Cameroon, Implication for Gold Exploration and Recovery  [PDF]
Germain Marie Monespérance Mboudou, Kennedy Folepai Fozao, Olivier Annoh Njoh, Christopher Mbaringong Agyingi
Open Journal of Geology (OJG) , 2017, DOI: 10.4236/ojg.2017.711115
Abstract: Field studies (location Au pits, sampling of different layers of sedimentary sequences filling the pits, panning of sediments), litho-stratigraphic investigations, grain size analysis and outlining of depositional conditions revealed a characteristic fining upward sequence in all the sections of 08 Au-pits within the Betare Oya basin. A typical profile is 2.5 to 4.5 m thick and is composed of a 30 to 50 cm organic topsoil layer, underlain by a 1.5 m thick reddish brownish gold free saprolite, which is underlain by 1.5 m sandy section. From litho-stratigraphic investigations and grain size analysis results a quartz dominated gravelly 1.4 m thick layer consisting in boulders (275 mm), cobbles (2-<20 mm) and subrounded pebbles (28 - 38 mm) mixed with sand grains (0.9 - 1.5 mm) and silt (0.01 - 0.02 mm). Pyrite, chalcopyrite and arsenopyrite are minor minerals and could be referred as to Au pathfinders (As, Fe, Cu). This layer overlays paleo-Proterozoic basement rocks (Nyong series) and is overlain by a poorly sorted sandy layer containing rounded whitish quartz grains and plagioclase fractions (Ca, Na), minor silts (0.02 - 0.2 mm), gravel and feldspar (K) leached from granitic plutons along shear zones in the area. The saprolite horizon overlaying the sandy layer derives from weathering and leaching of basement rocks under warm-humid climatic conditions. From gold grain count, the gravelly layer is the main productive horizon. Its upper layer (0.5 m) yields 02 Au grains per Kg of sampled materials while the 1 m-tick lower layer contains up to 34 Au-grains per sample and 13 g rains in 1 Kg of sampled materials. The sandy layer follows with averagely 02 Au grains per Kg as indication of partial leaching of primary mineralized rocks. Au concentration at depth (sandy and gravelly layers) is due to physical and chemical remobilization of Au in the secondary environment of deposition. Au is lithologically controlled and could be an important exploration factor in the study area. The calculated aspect ratios for pebbles from the gravelly and sandy layers disclosed two polynomial trends: 1) y = 0.0148x2 + 1.2187x + 2.0344, R2 = 0.6929 (sandy layer); 2) y = 0.0617x2 + 1.0849x + 0.8097, R2 = 0.8694 (gravelly layer); and y > R2 is satisfied in both cases. This implies that Au recovery from these layers could be effective
Geo-Electrical and Borehole Investigation of Groundwater in Some Basalts on the South-Eastern Flank of Mount Cameroon, West Africa  [PDF]
Anatole E. Djieto Lordon, Christopher M. Agyingi, Veronica E. Manga, Nenita N. Bukalo, Etienne T. Beka
Journal of Water Resource and Protection (JWARP) , 2017, DOI: 10.4236/jwarp.2017.912097
Abstract: The study area, located on the southwestern flank of Mt. Cameroon, is under-lain by basalts. The occurrence of groundwater in these rocks has been evaluated in order to determine their potentials as a source of water for a water bottling and soft drink plant. To achieve this, the constant separation traversing (CST) was used and the data qualitatively analyzed to determine the occurrence of fractures as most probable borehole sites. From this analysis, three sites were selected, sites at which a vertical electrical sounding (VES) was done and interpreted. Results obtained show a four layered earth profile model type KHKH, corresponding to a typical weathered/fractured confined aquifer type curve. This profile was later confirmed from borehole information after drilling at three of the selected sites. The comparison of VES data with geological sections is corroborative. A constant rate pumping test was done at rates as well as the investigation of other hydraulic properties. The results obtained for hydraulic properties investigated for all three boreholes reveal that productivity is very good and these results also reveal that at maximum exploitation rates, lowest tolerable drawdown for all three boreholes may not be reached after ten years. Chemical analysis done in-situ and on samples at the laboratory reveal that this water has a better mineralisation compared to other bottled water brands sold on the Cameroon market.
Sedimentology and Geochemical Evaluation of Lignite-Argillite Sequences in a Named Basin in Bali Nyonga, Northwest, Cameroon  [PDF]
Roger Ngong Ngia, Christopher M. Agyingi, Josepha Foba-Tado, Germain M. M. Mboudou, Anita Nshukwi, Victorine N. Beckley
International Journal of Geosciences (IJG) , 2015, DOI: 10.4236/ijg.2015.68074
Abstract: The sedimentology and geochemistry (major and trace element compositions) of lignite and argillite (carbonaceous shale and claystone) sequences in a Basin in Bali Nyonga, west of the Bamenda Mountain have been investigated to determine their sequences and the prevailing environmentalconditions which control their formation. Ten representative samples were obtained fromtrenches, pits, and river and stream valleys in the study area. These samples and their ashes were subsequently examined using X-ray fluorescence spectrometry (XRF), inductively coupled plasma spectrometry (ICP), and X-ray diffraction analysis (XRD). The geochemical results revealed that thelithophile, chalcophile and siderophile elements were dominantly epigenetic in origin, mainlyfrom detrital sources supported by high silica and alumina concentrations in all the samples. The mineral phases identified were quartz, kaolinite, illite, pyrite, hematite, and minor phases of feldspars,pseudorutile. The relatively high silica (54.10 wt%) and alumina contents (27.77 wt%) in thesesamples can be explained by high detrital input during peat formation. The low contents of MgO and CaO in the analysed samples agree very much with the continental setting of the peat formating basin. A clayey microband derived from alkaline volcanic ashes was identified in the lignite and the dominant composition of these clayey microbands was mixed-layer clay minerals of illite and kaolinte, which were interlayered with organic bands. The modes of occurrence of ash bands indicated that the volcanic activities were characterized by multiple eruptions, short time intervaland small scale for each eruption during peat accumulation. The ratios of redox-sensitive traceelement (V/Cr versus Ni/Co and V/V + Ni versus Ni/Co), Sr/Ba, and major oxides ratio (CaO + MgO + Fe2O
Trace Element Soil Quality Status of Mt. Cameroon Soils
Veronica E. Manga,Christopher M. Agyingi,Cheo E. Suh
Advances in Geology , 2014, DOI: 10.1155/2014/894103
Abstract: The concentrations of Cu, Co, Zn, Ni, V, and Cr in topsoils at six sites located along the lower slopes of Mt. Cameroon were assessed for their potential toxicity to humans and the ecosystem. Soils were collected from horizons down to a depth of 70?cm and analysed for trace element concentration by ICP-MS technique. The Dutch soil quality standards which use %clay/silt and organic matter content to derive target values were used to assess the contamination levels of the soils. The content of these soils was also compared to the United Kingdom ICRCL “soil trigger” values. Zinc and Cu values were persistently below the normal value (A) and occurred in the lower elevation, the region of extreme weathering, while Cr and V values were above the intervention (C) values. The high content of Cr in common fertilisers poses a potential risk in toxicity in the higher elevations experiencing lower weathering rates, where soil Cr levels are elevated. 1. Introduction Many trace elements are essential macro- and micronutrients for humans, plant growth, and the maintenance of healthy ecosystems. Micronutrients like Cu, Mn, Se, and Zn can be toxic at high concentrations in the soil. Trace elements unknown to be essential to plant growth, such as barium (Ba), cadmium (Cd), chromium (Cr), lead (Pb), and nickel (Ni), are toxic at high concentrations or under certain environmental conditions in soils. One of the major factors controlling soil trace element content is the parent rock material. Soils vary across landscapes and rock weathering and other soil-forming processes may result in the addition or removal of these elements from the soil. High background concentrations of trace elements, whether from natural or anthropogenic sources, could result in mobilization and release into surface and subsurface waters and subsequently incorporation into the food chain. Soil factors such as organic matter, type and amount of clay, pH, and cation exchange capacity (CEC) influence the quantity of trace elements available for mobilization and release or sorption in a soil [1]. Regulations to protect humans and the environment from toxicities and deficiencies related to trace elements are primarily based on soil quality reference values which are being developed in many countries. Many countries that have not developed their own formal guidelines follow the “Dutch standard” to support decision-making in assessing and monitoring soil quality. The Dutch are improving their soil quality in light of new scientific work particularly with regard to the impact of listed substances on living
Effect of an External Medium on Tumor Growth-induced Stress
Matthias Ngwa,Ephraim Agyingi
IAENG International Journal of Applied Mathematics , 2012,
Abstract:
Block Hybrid -Step Backward Differentiation Formulas for Large Stiff Systems
S. N. Jator,E. Agyingi
International Journal of Computational Mathematics , 2014, DOI: 10.1155/2014/162103
Abstract: This paper presents a generalized high order block hybrid -step backward differentiation formula (HBDF) for solving stiff systems, including large systems resulting from the semidiscretization parabolic partial differential equations (PDEs). A block scheme in which two off-grid points are specified by the zeros of the second degree Chebyshev polynomial of the first kind is examined for convergence, and stabilities. Numerical simulations that illustrate the accuracy of a Chebyshev based method are given for selected stiff systems and partial differential equations. 1. Introduction We consider the first order differential equation where , , , satisfies a Lipschitz condition, and the eigenvalues of the Jacobian have negative real parts (see [1]). It is well known that the system (1) is better handled by methods with larger stability intervals. In particular, -stable methods are of great importance. However, for very large systems arising from the semidiscretization of parabolic PDEs, -stable methods converge very slowly to the exact solution. Hence, we seek methods which are at least -stable for efficiently solving (1) when the system is very large (see Cash [2]). The development of continuous methods has been the subject of growing interest due to the fact that continuous methods enjoy certain advantages, such as the potential for them to provide defect control (see Enright [3]) as well as having the ability to generate additional methods, which are combined and applied in block form (see Onumanyi et al. [4, 5], Akinfenwa et al. [6], and Jator [7]). The majority of block methods which are due to Shampine and Watts [8], Chartier [9], Rosser [10], and Chu and Hamilton [11] are generally implemented in the predictor-corrector mode. In this paper, we adopt a different approach where the solution is simultaneously provided in each block (see Jator et al. [12], Jator [7, 13]) without the use of predictors from other methods. It is unnecessary to make a function evaluation at the initial part of the new block since at all blocks (with the exception the first block) the first function evaluation is already available from the previous block. The paper is structured as follows. Section 2 states the generalized block HBDF, its derivation from continuous approximation, and how to generate specific members of the scheme. The HBDFs are bundle as main and additional methods, a concept that is due to Brugnano and Trigiante [14]. In Section 3 we study the stability of the schemes with emphasis on a Chebyshev based member. In Section 4 a numerical algorithm for the block
Common Coupled Fixed Point Theorems for Maps in a $T_0$-ultra-quasi-metric Space
Collins Amburo Agyingi,Yaé Ulrich Gaba
Mathematics , 2014,
Abstract: In this article, we prove the existence of common fixed points for a pair of maps on a $q$-spherically complete $T_0$-ultra-quasi-metric space. The present article is a generalization, in the assymmetric setting of the paper of Rao et al.\cite{Rao}. The key point in the proof is the use of Zorn's lemma. We construct an appropriate chain and show that it has a maximal element, from which we extract the fixed point we are looking for. The choice of the sets, here open balls, is characteristic of this type of problems and the contraction condition are essential, specially when we are to establish the uniqueness of the fixed point
On Quasi-Pseudometric Type Spaces
Eniola Funmilayo Kazeem,Collins Amburo Agyingi,Yaé Ulrich Gaba
Chinese Journal of Mathematics , 2014, DOI: 10.1155/2014/198685
Abstract: We introduce the concept of a quasi-pseudometric type space and prove some fixed point theorems. Moreover, we connect this concept to the existing notion of quasi-cone metric space. 1. Introduction Cone metric spaces were introduced in [1] and many fixed point results concerning mappings in such spaces have been established. In [2], Khamsi connected this concept with a generalised form of metric that he named metric type. Recently in [3], Shadda and Md Noorani discussed the newly introduced notion of quasi-cone metric spaces and proved some fixed point results of mappings on such spaces. Basically, cone metric spaces are defined by substituting, in the definition of a metric, the real line by a real Banach space that we endowed with a partial order. The fact that the introduced order is not linear does not allow us to always compare any two elements and then gives rise to a kind of duality in the definition of the induced topology, hence the convergence in such space. We introduce a quasi-pseudometric type structure and show that some proofs follow closely the classical proofs in the quasi-pseudometric case but generalize them. 2. Preliminaries In this section, we recall some elementary definitions from the asymmetric topology which are necessary for a good understanding of the work below. Definition 1. Let be a nonempty set. A function is called a quasi-pseudometric on if(i) ,(ii) .Moreover, if , then is said to be a -quasi-pseudometric. The latter condition is referred to as the -condition. Remark 2. (i) Let be a quasi-pseudometric on ; then the map defined by whenever is also a quasi-pseudometric on , called the conjugate of . In the literature, is also denoted by or . (ii) It is easy to verify that the function defined by , that is, , defines a metric on whenever is a -quasi-pseudometric. Let be a quasi-pseudometric space. Then for each and , the set denotes the open -ball at with respect to . It should be noted that the collection yields a base for the topology induced by on . In a similar manner, for each and , we define known as the closed -ball at with respect to . Also the collection yields a base for the topology induced by on . The set is -closed but not -closed in general. The balls with respect to are often called forward balls and the topology is called forward topology, while the balls with respect to are often called backward balls and the topology is called backward topology. Definition 3. Let be a quasi-pseudometric space. The convergence of a sequence to with respect to , called -convergence or left-convergence and denoted by , is
Biostratigraphie des foraminiferes et interpretation paleoenvironnementale du puits opolo- i dans le delta du Niger, Nigeria
J.M Cheoh, C.E Bassey, C.M Agyingi
African Journal of Science and Technology , 2005,
Abstract: 115 déblais de sondage et des logs éléctriques ont été soumis aux analyses biostratigraphiques et paléoenvironnementales pour déterminer la lithologie, l’age, et l’environnement de dép t des sédiments provenant du puits Opolo-1 dans le Delta du Niger, Nigeria. Les résultats montre que du bas vers le haut de l’intervalle, les sédiments sont des argiles noires qui passent progresssivement aux sables argileux et finallement au grés au sommet du puits. Les grès sont plus ou moins bien triés, anguleux à subanguleux, fins à grossiers. La présence de la pyrite diagénétique dans toute la section étudiée nous amenent à conclure que le processus de dép t a eu lieu dans des conditions calmes et réductrices. 124 espèces de foraminifères comprenant 82 benthiques (66%) et 42 planctiques (34%) ont été identifiées et utilisées pour la datation, la biozonation et l’interpretation paléoenvironnemental. L’age du Miocène moyen au Pliocène inférieur est proposée. Sur la base du premier niveau d’apparition des foraminifères planctiques diagnostiques, six biozones ont été reconnues. Les paléoenvironnements de dép ts varient du néritique au bathyal et sont caractérisés par la présence d’espèces tel que Ammobacculites sp., Ammonia beccarii, Quinqueloculina lamarkiana dans les milieux néritiques et Bolivina scalprata miocenica, Cyclammina cancellata, et Heterolepa pseudoungeriana dans les zones bathyales.
What Role Can Propinquity Play in the Development of New National Allegiances? Immigrant Latinos Establishing Ties to the United States through Out-Group Contact  [PDF]
Christopher Olds
Advances in Applied Sociology (AASoci) , 2012, DOI: 10.4236/aasoci.2012.21002
Abstract: Contact theory has primarily been applied to the study of interactions between Blacks and Whites, with particular emphasis on changes in the attitudes of Whites towards Blacks. How individual contact with an out-group can influence not just attitudes, but also actual behavior, has not been thoroughly explored. Through an analysis of the 2006 Latino National Survey, using a measure that contrasts the intensity of individual social interaction with various ethnic and racial groups, the study shows that a high intensity of friendly social contact with African-Americans increases the likelihood Latino immigrants will establish a closer link to the social and political structures of the United States. Latino immigrants are potentially experiencing movement towards deprovincialization through high levels of friendly social interaction with African-Americans. The development of friendly personal interactions with an out-group stigmatized in the mother country can help Latino immigrants develop an optimistic view of life in the host country.
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