Open Access Method Article

Research on the Bearing Capacity of the Cross Section of Reinforced Concrete Beams Strengthened with Increasing Section Method Considering the Effect of the Second Loading

Ma Huixiang, Li Zhigang, Yue Zhang, Xu Haoran

Advances in Research, Page 1-9
DOI: 10.9734/AIR/2015/17399

The reinforcement construction of the structure in the presence of initial loads, which always results in the effect of a secondary load. However, the calculation method and formula on bearing capacity of normal section of reinforced concrete beams has not been clearly stated when considering the steel quantity and reinforcement proportional boundary in the reinforcing layer under the secondary load. By analyzing the ultimate damage of reinforced concrete beams strengthened by increasing the section at different initial loads, this paper studies the effects of secondary load on the maximum amount of reinforced steel and the normal section bearing capacity for reinforced concrete strengthened beams, getting the normal section bearing capacity calculation formula of reinforced concrete strengthened beam under the reinforcement steel boundary. Finite Element Analysis software Abaqus and mathematical formula derivation are adopted to calculate and analyze comparatively, which shows that the calculating results and these analysis were well agreed. The new algorithm simplifies the original calculation process and provides theoretical basis for structural reinforcement bearing capacity calculation.

 

Open Access Original Research Article

The Effects of More Realistic Forms of Lead Heterogeneity in Soil on Uptake, Biomass and Root Response of Two Brassica species

Grace O. Solomon-Wisdom, Michael H. Ramsey, Elizabeth A. John

Advances in Research, Page 1-26
DOI: 10.9734/AIR/2015/17975

The spatial heterogeneity of soil constituents is known to have significant impacts on plant growth and plant uptake of nutrients and contaminants, yet studies have rarely used patterns of heterogeneity based on those found in the field. Heterogeneity refers to how lumpy materials are distributed in the soil, whilst homogeneity is the uniformity in the distribution of such materials. We identified patterns of lead contamination at historically polluted field sites and conducted pot trials using field–based parameters to determine the pattern of distribution of lead within the pots. We examined plant Pb uptake and growth in simulated low, medium and high heterogeneity environments as well as a control homogeneous treatment. We found a significant effect of Pb spatial heterogeneity on uptake and biomass of two Brassica species (Brassica napus and Brassica juncea), both candidate species for phytoremediation projects. Biomass was 4 to 5 fold lower in the high heterogeneity treatment and total plant Pb uptake as Pb mass in (µg) was 40 to 80% lower, compared to the homogeneous treatment. Plant lead concentration (mg/kg) increased by a factor of 2 with increasing heterogeneity. Peak uptake was observed in low and medium heterogeneity treatments of B. napus and B. juncea respectively. We also explored roots behaviour in the high heterogeneity treatment and found variation in root mass by 20 to 80% between concentric patches with significant (P < 0.05) differences between patches and species. High proportion of roots (40 to 50%) were proliferated in patches of lower Pb concentration. The tap root was a greater proportion of root in B. napus, which was absent in B. juncea. Results suggest that root morphology of this plant species might be a factor influencing the placement of roots in concentric patches and consequently the overall root response to Pb spatial heterogeneity. This is an indication that the root response could be realistic of that experienced by plants in field conditions. Generally result showed that spatial heterogeneity of Pb has a significant effect on plant growth and biomass. This study also demonstrated that the presence and extent of in situ heterogeneity of Pb in soil plays an important role in Pb uptake by plants. This work has implications for improving the phytoremediation of Pb contaminated land, phytomining, the reliability of risk assessment/models of human exposure to Pb and the quality of trace mineral content of agricultural produce.

 

Open Access Original Research Article

The Constructivist Approach of Solving Word Problems Involving Algebraic Linear Equations: The Case Study of Mansoman Senior High School, Amansie West District of Ghana

Emmanuel Appoh Andam, Christopher Adjei Okpoti, William Obeng–Denteh, Evans Atteh

Advances in Research, Page 1-12
DOI: 10.9734/AIR/2015/13932

This paper is an action research which involves a sample of forty (40) second year students of Mansoman Senior High School. The study was aimed at using the constructivist approach to enhance students’ competence in solving word problems involving algebraic linear equations. Prior to the study, it was observed that the students were not able to understand and solve word problems under algebraic linear equations. The constructivist approach of teaching and learning was employed as the intervention strategy and was carried in a series of activities. The pre – test and post – test scores obtained by the students were analyzed quantitatively based on the research questions that preceded the study. Comparatively, the results obtained from the pre – test and post – test showed a significant improvement on the students’ ability to translate word problems into algebraic linear equations and solve the equations as well. It was then concluded from the findings that the constructivist approach of teaching and learning employed during the intervention processes improved the students’ academic achievements. The constructivist approach of teaching promoted students participation in the teaching and learning process and environment, and it must be encouraged by all.

 

Open Access Original Research Article

Material Selection for Gas Turbine Blade Coating Using GRANTA Material Selector

A. A. Abioye, P. O. Atanda, S. B. Majolagbe, D. A. Isadare, O. P. Abioye, K. J. Akinluwade, A. R. Adetunji

Advances in Research, Page 1-9
DOI: 10.9734/AIR/2015/15769

This paper presents the selection of suitable candidate materials for thermal barrier coating of gas turbine blade using GRANTA software. There have been reported cases of gas turbine blade failure in service due to the extreme service conditions. Such failure could possibly have occurred due to poor material selection for thermal barrier coatings on the turbine blade thereby exposing the blade to harsh condition over time. The major adverse effects on these blades are thermal fatigue, high temperature oxidation, hot corrosion, interdiffusion, high cycle fatigue and creep.

 

Open Access Original Research Article

A Retrospective Study of Cinara cupressivora Damage on Cupressus lusitanica Clonal Seed Orchard in Malawi between 1997 and 2003

Edward Missanjo, Gift Kamanga-Thole

Advances in Research, Page 1-7
DOI: 10.9734/AIR/2015/18609

A retrospective study covering a period of seven years (1997-2003) was conducted to assess the extent of damage of Cinara cupressivora on Cupressus lusitanica Orchard and determine any correlation with climatic factors in Dedza, Malawi. Furthermore, the study was also aimed at determining the efficacy of Pauesia juniperorum as a biological control. The data was extracted from monthly reports of the Forestry Research Institute of Malawi (Centre), where a total of 319 trees were assessed. A statistically significant (X2=13.97, P<0.001) association was found between the damage of the trees and increased number of C. cupressivora. The damage was found to be eighteen times (Odds Ratio=18.1) more likely to occur on trees attacked by C. cupressivora than those not attacked. The hot-dry season was found to be significantly (X2=8.6, P<0.001) associated with the increased number of C. cupressivora, and the damage was found to be three times (Odds Ratio=3.4) more likely to occur in this season compared to cold-wet and warm-wet seasons. Consequently, the results further show a significant (X2=26.37, P<0.001) association between the survival of trees and the presence of P. juniperorum. The trees attacked by C. cupressivora were found to be twenty-nine times (Odds Ratio=29.1) more likely to survive with the presence of P. juniperorum than those where the parasitic wasp were absent. It is, therefore, recommended that classical biological control is the most suitable and permanent solution for control. Hence, P. juniperorum is a potential agent for the biological control of C. cupressivora

 

Open Access Original Research Article

Application of Multiplicative and Additive Hazards Models to Injury Prevention among Healthcare Workers

Sabuj Sarker, Dae- Kee Min, Timothy R. Black, Hyun J. Lim

Advances in Research, Page 1-12
DOI: 10.9734/AIR/2015/18021

The Cox multiplicative model is used widely in survival analysis, where the covariates act multiplicatively on unknown baseline hazards. However, the Cox model requires the proportionality assumption, which limits its applications. The additive hazards model has been used as an alternative to the Cox model, where the covariates act additively on unknown baseline hazards. In this study, the performance of the Cox multiplicative hazards model and the additive hazards model has been demonstrated in an injury prevention study. Both the multiplicative and additive hazards models show similar results in selecting significant covariates in the final model in our study. The coefficient of the covariates in the additive hazards model is easy to interpret in an additive manner and should be considered when the proportionality assumption of the Cox model is doubtful. The multiplicative and additive hazards models describe different features of the association between the risk factors and the study outcomes. They may be used each other as supplementary approach for further understanding of the data.

 

Open Access Review Article

Biotechnological Potential of the Brazilian Caatinga Biome

Iasmim Lucas da Silva, Luana Cassandra Breitenbach Barroso Coel, Leonor Alves de Oliveira da Silva

Advances in Research, Page 1-17
DOI: 10.9734/AIR/2015/17426

The Caatinga biome is a unique Brazilian biome predominant in the Northeast of Brazil and situated in the Semiarid Region. The rhizosphere comprises the narrow zone of soil that is directly influenced by the roots of plants and associated soil microorganisms. It is a dynamic environment with maximum microbial activity due to the presence of root exudates and radicular secretions representing the major carbon source readily available to microorganisms. The typical rhizospheric community in the Caatinga biome comprises microorganisms with different types of metabolism and adaptive responses to changes depending on soil temperature, plant species, nutritional status, age, stress, illness, and other factors. Assays for a variety of soil enzymes give an indication of the functional diversity assumed by the microbes present. A useful characteristic of the rhizosphere isolates is the ability of the rhizobacteria to excrete enzymes such as cellulases and L-asparaginases. Among the important species found in the Caatinga biome is Poincianella pyramidalis, which is common in the Northeast of Brazil and is popularly known as “catingueira”. This plant species is heavily exploited by the local population as a source of firewood, charcoal, fodder and for medicinal purposes. This review will consider the structure of the Caatinga biome in terms of its biotechnological potential, with special emphasis on such components as the rhizosphere and enzymes associated with P. pyramidalis.