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Search Results: 1 - 10 of 461292 matches for " Nounagnon A. Vodounon "
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Compressive and Flexural Strengths of Cement Stabilized Earth Bricks Reinforced with Treated and Untreated Pineapple Leaves Fibres  [PDF]
Nounagnon A. Vodounon, Christopher Kanali, John Mwero
Open Journal of Composite Materials (OJCM) , 2018, DOI: 10.4236/ojcm.2018.84012
Abstract:
This study compares the effect of treated pineapple leaves fibres (T-PALF) with sodium hydroxide solution and untreated fibres (N-PALF) on the compressive and flexural strength of earth bricks stabilized with 3% and 5% cement. The fibre content ranged from 0% to 5% in steps of 1% by weight. The compressive strength tests were made at 7, 14, 21 and 28 days of curing; the flexural strength test were conducted at 28th day only. The results show that the T-PALF had a higher compressive strength when comparing to the N-PALF. The highest compressive strength of the bricks was obtained at 28 days of curing. The compressive strength at 28 days of stabilized brick at 3% and 5% of cement reinforced with T-PALF were 4.01 and 4.81 MPa, respectively, while the one reinforced with N-PALF was 3.19 and 4.63 MPa, respectively. The results further show that the highest flexural strength of both stabilized bricks at 3% and 5% of cement reinforced with T-PALF and N-PALF was obtained with the bricks stabilized with 5% of cement reinforced with T-PALF. This results show that bricks stabilized with 5% cement and reinforced with 3% of treated fibres content are good for construction of load bearing walls. It was observed; a significant improvement of the reinforced blocks under flexure than under compression.
Jiufeng Protected Area Biodiversity Threats Assessment
Antoine Sambou,Shenggao Cheng,Lei Huang,Charles Nounagnon Gangnibo
Journal of Agricultural Science , 2010, DOI: 10.5539/jas.v2n3p108
Abstract: Located in the East of Wuhan City, Jiufeng Protected area is endowed with a rich biodiversity in diversity landscape (Metasequoia forests, forest ponds, pine forest, Wetland pine, fir, cedar forest, Liquidambar forests, oak forests massoniana and lobular, Lin and mushroom). The objectives of this study were to assess and understand the biodiversity threats, evaluate activities, help prioritize and anticipate what threats might become more severe in the future. Threat assessment was based on a review of peer articles and secondary data sources such as key informant interviews. Interviews with local and provincial authorities and visits in the field were held to gather information on Jiufeng protected area resources and biodiversity threats. This research was carried out on June 2009. The Interviews, the literature review and field report showed that the biodiversity is threatened by a variety of human activities and natural factors such as climate change and invasive alien species. These threats can cause the biodiversity loss. In Jiufeng Protected Area, human activities such as land use and land cover change, industrialization and pollution, tourism and recreation constitute threats for biodiversity.
Sustainable Agriculture in Benin: Strategies for Applying the Chinese Circular Agriculture Model
Charles Nounagnon Gangnibo,Shenggao Cheng,Lei Huang,Antoine Sambou
Journal of Sustainable Development , 2010, DOI: 10.5539/jsd.v3n1p69
Abstract: Recently, many emerging economies try to follow the example of the West’s industrialization by developing material-intensive production systems. As a solution to the environmental problems caused by this kind of economic growth, China is implementing the concept of Circular Economy by drawing on the experiences from Germany, Denmark and Japan. This concept in agriculture is called ‘circular agriculture’. Benin through its Strategic Plan for Agricultural Sector Revival (PSRSA), wishes to attain poverty alleviation within short time (2008-2015). This study aimed to establish basic aspects required for Benin to adopt the circular agriculture which is in practice in China. Primary data from Government reports and interviews were used. The study shows how important agriculture is for food security in Benin. It also shows progress made by China in the path of Circular Economy in general and especially in circular agriculture. Through circular agriculture, Benin could achieve the goal of sustainable agriculture.
Management of Breast Cancer in Visceral Surgery of CNHU-HKM of Cotonou in Benin  [PDF]
Dansou Gaspard Gbessi, Ismail Lawani, Chrystelle Tawo-Nounagnon, Francis Moïse Dossou, Yacoubou Imorou Souaïbou, Delphin Kuassi Mehinto, Jean-Léon Olory-Togbe, Kémoko Osséni Bagnan, Nazaire Padonou
Surgical Science (SS) , 2016, DOI: 10.4236/ss.2016.73022
Abstract: Breast cancer affects more females than males. It occurs earlier with the black females and is often diagnosed at a stage of complication. This study aims to describe its epidemiological characteristics, the changing stages, and to analyze the treatment and means of interdisciplinary and international cooperation in its care and treatment. Our study was retrospective, descriptive and analytic on breast cancer patients received at CNHU-HKM of Cotonou between January 1, 2001 and December 31, 2013. Breast cancer accounts for 24.24% of mammary pathologies and most affects the left breast. Females aged from 40 to 59 years old are the most affected. For males, the average age was 47.5 years old. Patients mostly consult at a later stage where the tumor is already palpable with nodal metastasis. Breast echography and mammography had been done only for 23.85% of the cases. In an anatomical pathology perspective, the invasive ductal carcinoma was the most common type with 87.2%. For the therapeutical aspect, a radical mastectomy according to Patey was realized in 81.65% of the cases; 48.65% underwent a chemotherapy and 14.7% were able to do a radiotherapy. The chance at life for patients was decreasing while the life time is increasing. Also, the average life span of patients was increased by the combination of diverse types of treatments notably when radiotherapy is done. The incidence of breast cancers in Visceral Surgery A and B department of CNHU-HKM-Cotonou is increasing over years.
A Comparative Investigation of Lead Sulfate and Lead Oxide Sulfate Study of Morphology and Thermal Decomposition  [PDF]
S. A. A. Sajadi
American Journal of Analytical Chemistry (AJAC) , 2011, DOI: 10.4236/ajac.2011.22024
Abstract: The compound lead oxide sulfate PbSO4.PbO was prepared in our laboratory. The Thermal behavior of PbSO4 was studied using techniques of Thermogravimetry under air atmosphere from 25 to 1200°C. The identity of both compounds was confirmed by XRD technique. Results obtained using both techniques support same decomposition stages for this compound. The electron microscopic investigations are made by SEM and TEM. The compound is characterized by XRD and the purity was determined by analytical Methods. Also a series of thermogravimetric analysis is made and the ideal condition is determined to convert this compound to pure lead oxide.
Metal ion-binding properties of L-glutamic acid and L-aspartic acid, a comparative investigation  [PDF]
S. A. A. Sajadi
Natural Science (NS) , 2010, DOI: 10.4236/ns.2010.22013
Abstract: A comparative research has been developed for acidity and stability constants of M(Glu)1, M(Asp)2 and M(Ttr)3 complexes, which have been determined by potentiometric pH titration. Depending on metal ion-binding properties, vital differences in building complex were observed. The present study indicates that in M(Ttr) com-plexes, metal ions are arranged to the carboxyl groups, but in M(Glu) and M(Asp), some metal ions are able to build chelate over amine groups. The results mentioned-above demonstrate that for some M(Glu) and M(Asp) complexes, the stability constants are also largely determined by the affinity of metal ions for amine group. This leads to a kind of selectivity of metal ions, and transfers them through building complexes accompanied with glutamate and aspartate. For heavy metal ions, this building complex helps the absorption and filtration of the blood plasma, and consequently, the excursion of heavy metal ions takes place. This is an important method in micro-dialysis. In this study the different as-pects of stabilization of metal ion complexes regarding to Irving-Williams sequence have been investigated.
Determining the Basaltic Sequence Using Seismic Reflection and Resistivity Methods  [PDF]
A. Alanezi, A. Qadrouh
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.32B004
Abstract:

This study was carried out in Harat Rahat (south of Almadinah Almonwarah) using seismic reflection and resistivity methods. The main objectives of this study are to determine the extent of the basaltic layer and to define the subsurface faults and fractures that could affect and control the groundwater movement in the study area. A 2D seismic profile was acquired and the result shows that the subsurface in the study area has a major fault. We obtained a well match when the seismic result was compared with drilled wells. As a complementary tool, the resistivity method was applied in order to detect the groundwater level. The results of the resistivity method showed that six distinct layers have been identified. The interpretation of these six layers show that the first three layers, the fourth layer, the fifth layer and the bottom of the section indicated various subsurface structures and lithologies; various basaltic layers, fractured basalt, weathered basement and fresh basaltic layers, respectively. It is obvious that the eventual success of geophysical surveys depend on the combination with other subsurface data sources in order to produce accurate maps.

Equilibria and Stability in Glycine, Tartrate and Tryptophan Complexes, Investigation on Interactions in Cu(II) Binary and Ternary Systems in Aqueous Solution  [PDF]
S. A. A. Sajadi
Open Journal of Inorganic Non-metallic Materials (OJINM) , 2014, DOI: 10.4236/ojinm.2014.41001
Abstract:

The acidity and stability constants of M(Gly)1, M(Ttr)1, and M(Trp)1 M: Cu2+, Cu(Bpy2)2+, and Cu(Phen3)2+ complexes, were determined by potentiometric pH titration. It is shown that the stability of the binary Cu(L), (L: Gly, Ttr, and Trp) complex is determined by the basicity of the carboxylate group on one side and amino group on the other side. It is demonstrated that the equilibrium, Cu(Ha4)2+ + Cu(L) \"\"Cu(Har)(L) + Cu2+, is displacement due to the well known experience that mixed ligand complexes formed by a divalent 3d ion, a heteroaromatic N base and an O donor ligand possess increased stability. The stability constants of the 1:1 complexes formed between Cu2+, Cu(Bpy)2+ or Cu(Phen)2+

Adaptive Fuzzy Sliding Mode Controller for Grid Interface Ocean Wave Energy Conversion  [PDF]
Adel A. A. Elgammal
Journal of Intelligent Learning Systems and Applications (JILSA) , 2014, DOI: 10.4236/jilsa.2014.62006
Abstract:

This paper presents a closed-loop vector control structure based on adaptive Fuzzy Logic Sliding Mode Controller (FL-SMC) for a grid-connected Wave Energy Conversion System (WECS) driven Self-Excited Induction Generator (SEIG). The aim of the developed control method is to automatically tune and optimize the scaling factors and the membership functions of the Fuzzy Logic Controllers (FLC) using Multi-Objective Genetic Algorithms (MOGA) and Multi-Objective Particle Swarm Optimization (MOPSO). Two Pulse Width Modulated voltage source PWM converters with a carrier-based Sinusoidal PWM modulation for both Generator- and Grid-side converters have been connected back to back between the generator terminals and utility grid via common DC link. The indirect vector control scheme is implemented to maintain balance between generated power and power supplied to the grid and maintain the terminal voltage of the generator and the DC bus voltage constant for variable rotor speed and load. Simulation study has been carried out using the MATLAB/Simulink environment to verify the robustness of the power electronics converters and the effectiveness of proposed control method under steady state and transient conditions and also machine parameters mismatches. The proposed control scheme has improved the voltage regulation and the transient performance of the wave energy scheme over a wide range of operating conditions.

Geochemical Characteristics and Chemical Electron Microprobe U-Pb-Th Dating of Pitchblende Mineralization from Gabal Gattar Younger Granite, North Eastern Desert, Egypt  [PDF]
Hassan A. A. Shahin
Open Journal of Geology (OJG) , 2014, DOI: 10.4236/ojg.2014.41003
Abstract:

Pitchblende mineralization was studied in the younger granite samples collected from Gabal Gattar, north Eastern Desert, Egypt using electron scanning microscope (ESM) and electron probe microanalyses (EPMA). This study revealed that this pitchblende contains significant Zr content reaching up to (66.80% ZrO2), which suggests that volcanic rocks were probably the source of such a deposit. High level emplaced high-K Calc-alkaline plutons as Qattar granite may have been associated with their volcanic equivalent emplaced in the surrounding area or now eroded. Lead content of the pitchblende mineralization is high and with moderate volcanics (up to 7.71% PbO). In contrast, it is low in ThO2, Y2O3 and REE2O3. High Zr and Pb content associated with pitchblende mineralization from Gattar granite indicates

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