Numerical evaluation of the pipe-pile buckling during vibratory driving in sand

The buckling of steel pipe piles during vibratory driving is numerically studied using the Multi-Material Arbitrary Lagrangian-Eulerian (MMALE) method. This method handles the large soil deformations that occur during pile driving and other geotechnical installation processes. The Mohr-Coulomb and an elastic-perfectly plastic material model are used to model the soil and the pile mechanical behavior, respectively. The result of a small-scale pile driving experiment is used to validate the numerical model. The penetration trend agrees well with the experimental measurements. Thereafter, four case scenarios and their possible effects on pile buckling, namely the presence of heterogeneity in the soil (a rigid boulder inside the soil) and the existence of geometrical imperfection modes in the pile (ovality, out-of-straightness, flatness) are investigated. This study shows that a combination of local and global buckling initiates at the pile tip and the pile shaft, respectively. During the initiation of buckling, a decrease in the penetration rate of the pile is observed compared to the case where no or minimal buckling occurs. It is shown that a less portion of the driving energy is spent on the pile penetration and the rest is spent on other phenomena such as buckling, resulting in less pile penetration. The cross section of the pile tip after buckling takes a form of a “peanut”, yet with a different geometry for each case. In cases where the model was initially symmetric, an asymmetric shape in cross section of the pile tip was obtained at the final stage which can be attributed to complex soil-structure interaction. The results of the numerical approach provide promising results to be used as an evaluation tool to reach reliable predictions in pile installation practice

Numerical evaluation of the soil behavior during impact driving of pipe-piles

During the impact driving of pipe-piles, the soil is influenced in different ways including the void ratio, stress distribution, and plugging formation. Such effects may play an important role in structural design criteria such as the pile’s lateral support provided by the soil. Hence, this work is focused on investigating the change in the mechanical characteristics of the soil during impact driving using an advanced numerical analysis tool which is validated against an experiment. The investigation includes the pile penetration behavior, plugging formulation inside the pile, and the change of the lateral stress in the soil during the pile installation. The proposed numerical model is shown to provide similar results compared to experimental measurements. The void ratio of the soil is influenced due to pile driving up to a lateral and vertical distance of 2D and 1D, respectively, where D is the pile diameter. Compared to the initial void ratio, the soil inside the pile experienced loosening about 20% while the soil outside is densified about 30% during driving. Moreover, the induced lateral stress inside is more than the one outside the pile, indicating the formation of plugging. Compared to the initial lateral stress state, the pile installation increased the lateral stress up to four times inside and two times outside the pile. Based on the findings of this work, the effects of driving on soil mechanical properties are not minimal and may affect the pile performance including the lateral resistance of the pile. By using the numerical approaches such as one in this study, the evaluation of the various effects on the soil due to pile driving and gaining a better understanding of the such complex problems are possible

The effects of broodstock age on consecutive spawning performance of wild-caught ablated Fenneropenaeus

The effects of broodstock age on consecutive spawning performance of wild-caught ablated Fenneropenaeus indicus females in four age groups 6, 8, 12, and 14 months old were studied. Assessment duration was 30 days. Age groups were determined based on carapace length of broodstock caught from Jask fishing ground. Maximum female partnership percentage in consecutive spawning was for 12 months old group. Correlation between egg production and hatch in each spawning with number of spawning in 12 months old broodstock was weaker than other groups but this relation has negative and significant (r = -0.38, P0.05) but others groups had significantly higher hatch rate (P<0.05). In general, 12 month group of wild-caught ablated Fenneropenaeus indicus females showed much higher number of egg produced, hatch percentage, females partnership percentage for 4 spawning in the 30 days period

Assessment of extraction variables on agar gelling properties from cultural alga (Gracilariopsis persica) by RSM

In this present, response surface methodology was used to investigate the procedure of agar gelling properties from Gracilariopsis persica agarophyte and optimization them formulation. Base on result, three independent variables - alkalinity concentration (2-8%), extraction temperature (90-120°C) and extraction time (45-240 minutes) - in five levels on viscosity and hysteresis temperature were determined that effects of extraction time and temperature on viscosity and hysteresis temperature were significant (p0.05)

Drivers Affecting Bitcoin Adoption as a Payment Mechanism in the Tourism Industry

The authors received no financial support for the research, authorship and, or publication of this article.While travelers' desire to visit the world's most remote places has grown, the inefficiency of global payments indicates a significant barrier to tourism growth. As an emerging, decentralized, and borderless digital innovation, Bitcoin technology seems to have the ability to serve as a payment alternative and address such fundamental inefficiencies. On the other hand, bitcoin adoption can only happen when tourists and business owners choose to operate bitcoin simultaneously. The study has developed a novel Bitcoin Collaborative Network and Tourism Collaborative Network model to examine Bitcoin adoption factors. Then a fuzzy DEMATEL method was applied to the factors influencing the adoption domain, as identified based on an extensive literature review, in-depth interviews, and an international Delphi process. The study offered a model for the heterogeneous collaborative network of Bitcoin and Tourism (BCN and TCN), revealing that Perceived Usefulness is the most influencing criterion and the most prominent variable in Bitcoin Adoption. Bitcoin Technological Complexity, Government Regulatory, and Bitcoin Awareness are the factors that give the highest impacts. Also, Bitcoin's Technological Complexity is the most significant factor in bitcoin adoption. The findings might assist businesses in adopting a new market expansion strategy and benefiting from technological spillover, while government officials can explore new supporting legislation.publishersversionpublishe

Factors Affecting Sustainable Rice Farming:The Case of Rice Farmers in the Mazandaran Province, Iran

In recent years, the production of high-yielding rice varieties in the Mazandaran province due to lack of attention in the environmental issues, has led to undesirable consequences. According to the key role of the farmers in the performanceof the sustainable agriculture principles, and the importance of their sustainability practices, the present study aimed to identify the factors affecting sustainability behavior of farmers regarding high-yielding rice varieties farming in the Mazandaran province. This study is based on survey method and statistical sample is selected 270 rice farmers of Amol, Babol and Sari counties in this province. Data were collected using questionnaire. The most important findings of the study shows that there is a positive and significant relationship between the managerial features, putting the value of the reference group opinions, sustainability attitudes, access to educational-extension and communicational factors, access to inputs and feasibility of sustainable agriculture methods, and farmers’ behavior regarding sustainability. Based on the results, feasibility of sustainable agriculture methods, access to educational-extensionand communicational factors, managerial features, putting the value of the reference group opinions and sustainability attitudes, explain 49% of sustainability behavior variations. Some recommendations have been provided based on the findings

Assessment of Yield Loss in Rice due to Yellow Stem Borer, Scirpophaga incertulas, Using Simulation Models

The yield loss simulation (YLS) and the MACROS LIQ.CSM models were used to simulate the effect of stem borer damage at a detillering rate of 5, 15, 30, 60% at vegetative, panicle initiation and grain filing stages, on yield of rice cultivar’s Ratna. This stem borer damage during vegetative and panicle initiation stages was not simulated appropriately by both the models. Relatively MACROS simulated pest effects better than YLS at this stage. The predicted reduction in yield due to detillering at grain filling stage varied from 10.93-62.5 and 2.59-57.2% with the YLS and MACROS models, respectively in comparison to observed reduction of 4.8-56.1%. The simulated and observed pest effects on crop yield during grain filling stage were found to be comparable