Comparative Evaluation on the Coupled Fracture Characteristics for Longmaxi Anisotropic Shale

AbstractThe shale fracture characteristics are important for realizing the complex hydraulic fracture network, predicting wellbore fracture pressure, and optimizing wellbore trajectory and the rock fragmentation efficiency. Through a three-point bending test of notched semicircular specimens of Longmaxi shale, the coupled relationship of mode-I fracture toughness (Kic), peak fracture force (Pmax), energy release rate (GI), applied work (W), and loading rate was studied by using kernel density analysis method. The results showed that the dynamic characteristics of force-displacement curve exhibited obvious loading angle dependence, including two types of the “deformation accumulation-brittleness” and “deformation accumulation-brittleness-plasticity.” The Kic and GI increased linearly with Pmax increasing. With the increasing of the loading angle, the dispersion degree of Pmax, Kic, GI, and W all increased. The GI increased nonlinearly with the increasing of Kic. With the increasing of the loading rate, the Kic basically increased linearly. The dynamic Kic under static and quasistatic conditions had strong anisotropy. At the high loading rate, the anisotropy index gradually decreased as the loading rate increasing. The results have significant implications for the design of hydraulic fracturing and the exact fracture control of Longmaxi shale

Evaluation of the environmental impacts of rice paddy production using life cycle assessment: case study in Bangladesh

The world is heading towards sustainability. Environmental dimension of sustainability is getting momentum and therefore it is imperative to know the peril through environmental load of a product, process, or activity throughout its life cycle. This study focuses on life cycle assessment (LCA) of rice production in Bangladesh, the fourth highest producer of rice in the world. The objective of this study was to estimate the different environmental impacts from production of paddy rice, in a typical scenario, and identify the environmental hotspots. A life cycle impact assessment has been carried out using ReCiPe methodology, which consists of 18 midpoint impact indicators. The resulting LCA has pointed out the magnitude of impact per kg of paddy produced from the harvested field; a CO2eq emission of 3.15 kg as global warming potential, a P-eq emission of 0.00122 kg as freshwater eutrophication, fossil depletion of 0.68 kg oil(eq), a 1,4-DCB-kg oil(eq) emission of 1.15 kg as human toxicity, a NMVOC emission of 0.016 kg as particulate matter formation, a N-eq emission of 0.0154 kg as marine eutrophication and use of 2.97 m(3) of water for irrigation purpose. Contribution analysis shows that irrigation and emissions from paddy field are the most environmentally burdening stages across all major impact categories. Manufacture of fertilizer and pesticide also play a significant role in putting environmental load. The application of this study helped to identify improvement opportunities to reduce environmental impacts within this and related production systems, and demonstrated its usefulness in setting priorities to realize these opportunities

Evaluating the Effectiveness of Continuous Composite Beams for Steel-Concrete Bridges and Control Concrete Cracks of the Supports at an Early Age

This study presents a solution to contextualized span bridges constructed with composite steel girders with reinforced concrete slabs by reinforced concrete. This kind of structure, in comparison with a simple span, has many advantages as overcoming internal forces, reducing large displacements and cutting the number of expansion joints. Also, numerical simulations were conducted to evaluate the effectiveness of continuous composite beams for steel-concrete bridges and control of cracking of concrete at the supports at an early age. The models and conclusions in this paper can provide safety guidance for construct composite steel girder bridge in Vietnam

The study of public administration in India, the Philippines, Canada and Australia: the universal struggle against epistemic colonization, and toward critical assimilation

The study of public administration has been characterized as a strong international focus, as both governments and scholars have sought to learn from the experience of other societies. While in a perfect world, one would expect a sort of pragmatic universalism, instead, many scholars tend to bring lessons from one country, or from a single cultural reality. This modest contribution lies in showing a series of national experiences rarely brought to the discourse about public administration in Brazil: Canada, Australia, India and the Philippines. Special emphasis will be given to the following: the origins and the development of public administration; the influence of ideology; and the complex tension between global theory and local practices