Large Scale Physical Modelling for a Floating Concrete Caisson in Marine Works

2018 ◽  
Author(s):  
Lucía Meneses ◽  
Javier Sarmiento ◽  
Daniel de los Dolores ◽  
David Blanco ◽  
Raúl Guanche ◽  
...  
Keyword(s):  
Life Cycle ◽  
Numerical Model ◽  
Large Scale ◽  
Physical Modelling ◽  
Dynamic Positioning ◽  
Construction Process ◽  
Important Advance ◽  
Positioning Control ◽  
Floating Structures ◽  
Vertical Breakwater

In the last years, the use of floating concrete caissons in coastal infrastructures has been generalized: docking structures, vertical breakwater and special floating structures. In this field, one of the most important and less analyzed stages of the marine works is the sinking process of the floating caissons. The test campaign presented in this work is innovative in scale (1:12) and includes an analysis of the different stages of a floating caisson during its life cycle: detached concrete caisson, caisson positioning and sinking and berthed floating caisson, resulting in more than 130 tests performed. Movements and tensions have been analyzed for a wide array of sea states and different configurations of mooring systems and horizontal layouts. A new tool for dynamic positioning control was designed and developed as part of the test campaign. The design of this tool has led to the development of a specific numerical model that reproduced the dynamic behavior during sinking. The dynamic positioning control was implemented in the physical model campaign, which has meant an important advance in the construction process of maritime infrastructures. Moreover, the campaign carried out has allowed the validation and calibration of the tools developed, allowing all the work to reduce costs and increase the safety of these types of marine operations.

scholarly journals Carbon Emission Estimation of Assembled Composite Concrete Beams during Construction

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1810
Author(s):  
Kaitong Xu ◽  
Haibo Kang ◽  
Wei Wang ◽  
Ping Jiang ◽  
Na Li
Keyword(s):  
Life Cycle ◽  
Carbon Emissions ◽  
Emission Reduction ◽  
Carbon Emission ◽  
Composite Beams ◽  
Total Carbon ◽  
Construction Process ◽  
Low Carbon ◽  
Carbon Emission Reduction ◽  
The Government

At present, the issue of carbon emissions from buildings has become a hot topic, and carbon emission reduction is also becoming a political and economic contest for countries. As a result, the government and researchers have gradually begun to attach great importance to the industrialization of low-carbon and energy-saving buildings. The rise of prefabricated buildings has promoted a major transformation of the construction methods in the construction industry, which is conducive to reducing the consumption of resources and energy, and of great significance in promoting the low-carbon emission reduction of industrial buildings. This article mainly studies the calculation model for carbon emissions of the three-stage life cycle of component production, logistics transportation, and on-site installation in the whole construction process of composite beams for prefabricated buildings. The construction of CG-2 composite beams in Fujian province, China, was taken as the example. Based on the life cycle assessment method, carbon emissions from the actual construction process of composite beams were evaluated, and that generated by the composite beam components during the transportation stage by using diesel, gasoline, and electric energy consumption methods were compared in detail. The results show that (1) the carbon emissions generated by composite beams during the production stage were relatively high, accounting for 80.8% of the total carbon emissions, while during the transport stage and installation stage, they only accounted for 7.6% and 11.6%, respectively; and (2) during the transportation stage with three different energy-consuming trucks, the carbon emissions from diesel fuel trucks were higher, reaching 186.05 kg, followed by gasoline trucks, which generated about 115.68 kg; electric trucks produced the lowest, only 12.24 kg.

scholarly journals Comparative Analysis of the Life-Cycle Cost of Robot Substitution: A Case of Automobile Welding Production in China

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 226
Author(s):  
Xuyang Zhao ◽  
Cisheng Wu ◽  
Duanyong Liu
Keyword(s):  
Life Cycle ◽  
Systems Engineering ◽  
Life Cycle Cost ◽  
Manufacturing Systems ◽  
Large Scale ◽  
Cost Allocation ◽  
Industrial Robot ◽  
Case Analysis ◽  
Industrial Robots ◽  
Analysis Model

Within the context of the large-scale application of industrial robots, methods of analyzing the life-cycle cost (LCC) of industrial robot production have shown considerable developments, but there remains a lack of methods that allow for the examination of robot substitution. Taking inspiration from the symmetry philosophy in manufacturing systems engineering, this article further establishes a comparative LCC analysis model to compare the LCC of the industrial robot production with traditional production at the same time. This model introduces intangible costs (covering idle loss, efficiency loss and defect loss) to supplement the actual costs and comprehensively uses various methods for cost allocation and variable estimation to conduct total cost and the cost efficiency analysis, together with hierarchical decomposition and dynamic comparison. To demonstrate the model, an investigation of a Chinese automobile manufacturer is provided to compare the LCC of welding robot production with that of manual welding production; methods of case analysis and simulation are combined, and a thorough comparison is done with related existing works to show the validity of this framework. In accordance with this study, a simple template is developed to support the decision-making analysis of the application and cost management of industrial robots. In addition, the case analysis and simulations can provide references for enterprises in emerging markets in relation to robot substitution.

A large-scale study of ionic liquids employed in chemistry and energy research to reveal cytotoxicity mechanisms and to develop safe design guide

2021 ◽  
Author(s):  
Lilya U. Dzhemileva ◽  
Vladimir Anatolievich D'yakonov ◽  
Marina M. Seitkalieva ◽  
Natalia Kulikovskaya ◽  
Ksenia S. Egorova ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Life Cycle ◽  
Large Scale ◽  
Energy Research ◽  
Organic Electrolytes ◽  
Large Scale Study ◽  
Design Guide ◽  
Scientific Potential

Device-level applications of organic electrolytes unavoidably imply extensive contacts with the environment. Despite their excellent scientific potential, ionic liquids (ILs) cannot be approved for practical usage until their life cycle...

scholarly journals An integrated life cycle and water footprint assessment of nonfood crops based bioenergy production

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jun Li ◽  
Fengyin Xiong ◽  
Zhuo Chen
Keyword(s):  
Life Cycle ◽  
Environmental Sustainability ◽  
Large Scale ◽  
Water Footprint ◽  
Arable Land ◽  
Integrated Analysis ◽  
Actual Performance ◽  
Bioenergy Production ◽  
Trade Offs ◽  
Hybrid Pennisetum

AbstractBiomass gasification, especially distribution to power generation, is considered as a promising way to tackle global energy and environmental challenges. However, previous researches on integrated analysis of the greenhouse gases (GHG) abatement potentials associated with biomass electrification are sparse and few have taken the freshwater utilization into account within a coherent framework, though both energy and water scarcity are lying in the central concerns in China’s environmental policy. This study employs a Life cycle assessment (LCA) model to analyse the actual performance combined with water footprint (WF) assessment methods. The inextricable trade-offs between three representative energy-producing technologies are explored based on three categories of non-food crops (maize, sorghum and hybrid pennisetum) cultivated in marginal arable land. WF results demonstrate that the Hybrid pennisetum system has the largest impact on the water resources whereas the other two technology options exhibit the characteristics of environmental sustainability. The large variances in contribution ratio between the four sub-processes in terms of total impacts are reflected by the LCA results. The Anaerobic Digestion process is found to be the main contributor whereas the Digestate management process is shown to be able to effectively mitigate the negative environmental impacts with an absolute share. Sensitivity analysis is implemented to detect the impacts of loss ratios variation, as silage mass and methane, on final results. The methane loss has the largest influence on the Hybrid pennisetum system, followed by the Maize system. Above all, the Sorghum system demonstrates the best performance amongst the considered assessment categories. Our study builds a pilot reference for further driving large-scale project of bioenergy production and conversion. The synergy of combined WF-LCA method allows us to conduct a comprehensive assessment and to provide insights into environmental and resource management.

scholarly journals Is Agriculture Always a GHG Emitter? A Combination of Eddy Covariance and Life Cycle Assessment Approaches to Calculate C Intake and Uptake in a Kiwifruit Orchard

2021 ◽  
Vol 13 (12) ◽  
pp. 6906
Author(s):  
Federica Rossi ◽  
Camilla Chieco ◽  
Nicola Di Virgilio ◽  
Teodoro Georgiadis ◽  
Marianna Nardino
Keyword(s):  
Life Cycle Assessment ◽  
Life Cycle ◽  
Greenhouse Gases ◽  
Eddy Covariance ◽  
Large Scale ◽  
Cropping Systems ◽  
Substantial Reduction ◽  
Co2 Absorption ◽  
Positive Contribution ◽  
Efficiency Ratio

While a substantial reduction of GHG (greenhouse gases) is urged, large-scale mitigation implies a detailed and holistic knowledge on the role of specific cropping systems, including the effect of management choices and local factors on the final balance between emissions and removals, this last typical of cropping systems. Here, a conventionally managed irrigated kiwifruit orchard has been studied to assess its greenhouse gases emissions and removals to determine its potential action as a C sink or, alternately, as a C source. The paper integrates two independent approaches. Biological CO2 fluxes have been monitored during 2012 using the micrometeorological Eddy covariance technique, while life cycle assessment quantified emissions derived from the energy and material used. In a climatic-standard year, total GHG emitted as consequence of the management were 4.25 t CO2-eq−1 ha−1 yr−1 while the net uptake measured during the active vegetation phase was as high as 4.9 t CO2 ha−1 yr−1. This led to a positive contribution of the crop to CO2 absorption, with a 1.15 efficiency ratio (sink-source factor defined as t CO2 stored/t CO2 emitted). The mitigating activity, however, completely reversed under extremely unfavorable climatic conditions, such as those recorded in 2003, when the efficiency ratio became 0.91, demonstrating that the occurrence of hotter and drier conditions are able to compromise the capability of Actinidia to offset the GHG emissions, also under appropriate irrigation.

Simulation on Rationalization Process Scheduling in Large-Scale Civil Engineering

2014 ◽  
Vol 602-605 ◽  
pp. 571-574
Author(s):  
Mao Liu
Keyword(s):  
Large Scale ◽  
Civil Engineering ◽  
Scheduling Algorithm ◽  
Construction Process ◽  
Process Scheduling

In the construction process of large-scale civil engineering and architecture, how to realize rational scheduling is a key problem need to be solved. This paper studies the construction process of the large-scale Civil Engineering decoration companies, particularly the construction with parallel multiple sets of team and multi-project. To solve the problem, the paper designs a special scheduling algorithm and carries out simulation. The scheduling algorithm shorts the duration of construction and improves enterprise efficiency.

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