Dynamic Failure Investigation in Ultrafi ne Grained AA2219: Mechanical and Microstructural Analysis

Amin Azimi,Gbadebo Moses Owolabi,Nikhil Kumar,Grant Warner 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.4

In this study, the high strain rate behavior of ultrafi ne grained (UFG) AA2219 alloy processed via multi axial forging atcryogenic temperature was investigated. Room temperature forged sample was used as a reference to determine the eff ectsof signifi cant grain size refi nement on the dynamic response of the materials. The initial microstructure characterizationindicated that severe plastic deformation in the cryogenically process alloy resulted in its grain size reduction to ~ 270 nmand the second phase breakage to fi ner particles. The results of the dynamic impact tests show that the strain hardening andthermal softening are substantially less signifi cant in the UFG materials, whereas the maximum fl ow stress and the strain ratesensitivity increased. Furthermore, the grain size reduction led to the absorption of higher portion of the deformation energyand an increase in the toughness of the fabricated UFG material when compared to the conventionally forged samples. Thisimprovement is approximately 56% at a strain rate of 4000 s −1 obtained via the grain structure refi nement. Microstructureanalysis of the post-deformed samples revealed two fully transformed adiabatic shear bands (ASBs) in the coarser grainedmaterial due to intense localized strain and thermal instability during the impact tests which caused the pushing off of thesecond phases and cracks formation inside the ASBs. However, low-intensity deformed ASBs and a notable enhancementin crack initiation strength were observed by morphology and fi nal confi guration of the post-deformed UFG samples. Inaddition, no considerable hardness variations were experienced in the impacted UFG material due to the saturation of grainsize during the cryogenically forging process. In contrary to the UFG alloys, signifi cant hardness increase was observed inthe deformed coarse grained material which was associated with softening in the adjacent regions providing a zone proneto cracks initiation.

Aqueous extract of Moringa oleifera Lam. induced mitodepression and chromosomal aberration in Allium cepa, and reproductive genotoxicity in male mice

Adekunle A. Bakare,Andreal Akpofure,Adeyinka M. Gbadebo,Olukunle S. Fagbenro,Ifeoluwa T. Oyeyemi 경희대학교 융합한의과학연구소 2022 Oriental Pharmacy and Experimental Medicine Vol.22 No.4

Moringa oleifera is a multipurpose plant with nutritional and medicinal value. Despite its widely acclaimed therapeutic benefits in traditional medicine, there are reports on its toxicity in living cells. Information is however, limited on toxic effect of the plant on the genetic component and male reproductive cells. We evaluated genotoxicity of aqueous extract of the leaves of M. oleifera using the Allium cepa chromosome aberration (CA) and mouse sperm morphology assays. Roots of onion bulbs were exposed to 0.5–20% of the extract for analysis of root growth inhibition, mitotic index (MI) and CA. Swiss male mice orally exposed to the aqueous extract (50–800 mg/kg) for 35 consecutive days were analysed for body and testes weight, testicular histology and sperm morphology. There was a significant (p < 0.05) root growth inhibition, decrease in MI and induction of CA compared to the negative control bulbs. The extract did not cause adverse effect on body and testes weight, but maturation arrest, atrophy and germ cell sloughing and degeneration were observed in testicular sections of exposed mice. A significant increase in sperm morphology was observed in exposed mice relative to the control group. Aqueous extract of M. oleifera was cytotoxic, mitodepressive and genotoxic in A. cepa. It induced DNA damage in the sperm head and interfered with spermatogenesis. This suggests potentials of M. oleifera to modulate somatic cell cycle and impact male fertility.

Conceptualizing 5G’s of Green Marketing for Retail Consumers and Validating the Measurement Model Through a Pilot Study

Hafiz Waqas Ahmed ANSARI,Waida Irani Mohd FAUZI,Maruf Gbadebo SALIMON 한국유통과학회 2022 유통과학연구 Vol.20 No.4

Purpose: This pilot study aims to conceptualize a new green marketing mix for retail consumers based on Stimulus-Organism-Response (SOR) model. Moreover, it also aims to conceptualize a testable research model of new green marketing mix with consumers’ green purchasing behavior, and to validate the measurement model with traditional as well as modern suggested validating techniques. Research design, data and methodology: A pilot test data from 75 respondents of retail buyers of energy-efficient electric appliances in Pakistan were tested for the confirmatory factor analysis (CFA) by examining a measurement model of the construct through different validation techniques (like Composite Reliability, McDonald’s Omega (ω), rho (ρA), HTMT, etc.) as heretofore these scales were not validated through these modern methods. Results: The results revealed that the instrument has a certain degree of reliability and validity through different validating techniques. All the measurement items reach the suggested threshold values. Conclusions: Therefore, this study conceptualized an integrated framework of all the three stakeholders of the environment (government, companies, and public or consumers) to achieve environmental sustainability. Hence, future studies can extend these findings and conduct a full-scale study to establish an empirical relationship between the 5G’s of green marketing for retailing businesses and consumers’ green purchase behavior.

The Influence of Organizational External Factors on Construction Risk Management among Nigerian Construction Companies

A.Q. Adeleke,A.Y. Bahaudin,A.M. Kamaruddeen,J.A. Bamgbade,Maruf Gbadebo Salimon,Muhammad Waris Ali Khan,Shahryar Sorooshian 한국산업안전보건공단 산업안전보건연구원 2018 Safety and health at work Vol.9 No.1

Background: Substantial empirical research has shown conflicting results regarding the influence of organizational external factors on construction risk management, suggesting the necessity to introduce a moderator into the study. The present research confirmed whether rules and regulations matter on the relationships between organizational external factors and construction risk management. Methods: Based on discouragement and organizational control theory, this research examined the effects of organizational external factors and rules and regulations on construction risk management among 238 employees operating in construction companies in Abuja and Lagos, Nigeria. A personally administered questionnaire was used to acquire the data. The data were analyzed using partial least squares structural equation modeling. Results: A significant positive relationship between organizational external factors and construction risk management was asserted. This study also found a significant positive relationship between rules and regulations and construction risk management. As anticipated, rules and regulations were found to moderate the relationship between organizational external factors and construction risk management, with a significant positive result. Similarly, a significant interaction effect was also found between rules and regulations and organizational external factors. Implications of the research from a Nigerian point of view have also been discussed. Conclusion: Political, economy, and technology factors helped the construction companies to reduce the chance of risk occurrence during the construction activities. Rules and regulations also helped to lessen the rate of accidents involving construction workers as well as the duration of the projects. Similarly, the influence of the organizational external factors with rules and regulations on construction risk management has proven that most of the construction companies that implement the aforementioned factors have the chance to deliver their projects within the stipulated time, cost, and qualities, which can be used as a yardstick to measure a good project.

The Influence of Organizational External Factors on Construction Risk Management among Nigerian Construction Companies

Adeleke, A.Q.,Bahaudin, A.Y.,Kamaruddeen, A.M.,Bamgbade, J.A.,Salimon, Maruf Gbadebo,Khan, Muhammad Waris Ali,Sorooshian, Shahryar Occupational Safety and Health Research Institute 2018 Safety and health at work Vol.9 No.1

Background: Substantial empirical research has shown conflicting results regarding the influence of organizational external factors on construction risk management, suggesting the necessity to introduce a moderator into the study. The present research confirmed whether rules and regulations matter on the relationships between organizational external factors and construction risk management. Methods: Based on discouragement and organizational control theory, this research examined the effects of organizational external factors and rules and regulations on construction risk management among 238 employees operating in construction companies in Abuja and Lagos, Nigeria. A personally administered questionnaire was used to acquire the data. The data were analyzed using partial least squares structural equation modeling. Results: A significant positive relationship between organizational external factors and construction risk management was asserted. This study also found a significant positive relationship between rules and regulations and construction risk management. As anticipated, rules and regulations were found to moderate the relationship between organizational external factors and construction risk management, with a significant positive result. Similarly, a significant interaction effect was also found between rules and regulations and organizational external factors. Implications of the research from a Nigerian point of view have also been discussed. Conclusion: Political, economy, and technology factors helped the construction companies to reduce the chance of risk occurrence during the construction activities. Rules and regulations also helped to lessen the rate of accidents involving construction workers as well as the duration of the projects. Similarly, the influence of the organizational external factors with rules and regulations on construction risk management has proven that most of the construction companies that implement the aforementioned factors have the chance to deliver their projects within the stipulated time, cost, and qualities, which can be used as a yardstick to measure a good project.