Papers by Keyword: Life Cycle

Abstract: This paper presents a procedure to select a pavement structure from technically established alternatives. The general proposed process relies on calculating the present worth of total cost resulting from construction, maintenance/rehabilitation, energy consumption and carbon footprint during those activities as well as recycling of the materials at their end life. However, depending on data availability, the general process could be reduced to just the construction phase as is the case in most developing countries where required pavement performance data is scarce. The reduced procedure was validated on four types of pavements for six traffic levels and three subgrade types. Under the conditions considered in this study, it was found that concrete pavements have high construction, embodied energy, and carbon footprint costs (the environmental impact represents about 66% of the total cost) as compared to other pavement types. Full-depth asphalt pavements were found to be the best ecological type, their construction cost is a little higher than the environmental one with a distribution of about 53% and 47%, respectively. Inverted pavements seem to be a good alternative to weak subgrades although the costs associated with environmental effects contribute to about 52% of the total cost.

Abstract: In this paper, based on the life cycle concept of oil sludge waste from the NdFeB manufacturing process, we investigate the process technology route to recover valuable elements from the oil sludge waste by hydro-metallurgical refining and calcium reduction to fabricate a sintered NdFeB magnet. The life cycle list was calculated and the environmental impact of the main processes was examined using the ReCiPe method, and the main factors of environmental impact were identified. The results showed that the hydrometallurgical technology route, compared with the calcium reduction technology route, resulted in 119.84% of human health hazards, 119.84% of ecological damage and 119.84% of resource. The consumption was found to be 13.08% higher than that of FDP. The sensitivity analysis revealed that the production of hydrochloric acid is highly sensitive to FDP, and power consumption is high to WTP in the hydrometallurgical technology route, and WTP in the calcium reduction unit process, and HTP in all processes in the calcium reduction technology route. The overall results show that reducing the environmental impact in the calcium reduction recovery process and accelerating the clean production of China's power resources are of great significance for the recovery of oil sludge waste for the preparation of recycled sintered NdFeB.

Abstract: The article presents the results of comparative studies of the stress-strain behavior of duck-foot tines made of steel and isotropic fiberglass. The studies were carried out on full-size 3D models of the SKP 01.08.080 (1) part being used on SZS-2.1 type seeders of various manufacturers widely spread in our soil and climatic zone. For the research, we used specialized software: CAD Autodesk Inventor and SolidWorks CAD/CAM system. Models were fastened and loaded using a distributed force of 650 N applied to the toe and wings of a duck-foot tine corresponding to the draught resistance of the part under conditions of its real operation at a speed of movement of up to 2.23 m/s. It has been shown that the deformations occurring in a duck-foot tine made of fiberglass 5...6 mm thick have a magnitude of 1.5...2 times less than those in a steel tine, the strength reserve factor of the steel and composite parts is the same and equals 15, however, its distribution over the part surface is uneven, so the predicted life cycle of the fiberglass part will be 2 times longer than that of the steel part.

Abstract: The water consumption intensity of steel production through BF-BOF technology was decomposed by an innovative process-based water-accounting model, i.e., water-balance model. One ton of steel product was chosen to be the functional unit. The system boundary of the case study included the production processes of coking, sintering, iron making, steel making, continuous casting and rolling. The results showed that the water consumption intensity of steel production was 3.969t/t in this case. The water consumption of evaporation, solidification and wastewater were 2.373t, 0.013t and 1.583t, accounting for 59.79%, 0.33% and 39.88% of the total water consumption, respectively. Steel rolling is the largest contributor to water consumption, and the amount of water consumption is 1.523t, accounting for 38.37% of the total water consumption; followed by coking process and continuous casting process, the amounts of which are 0.814t (20.50%) and 0.634t (15.97%), respectively. This finding can push the utilization of advanced technologies to save water resource in steel industry.

Abstract: Green building materials have drawn more and more attention of the Chinese Government. Carbon footprint research on typical building materials products in China is of great significance to promote the sustainable development of building materials industry and realize the objectives of series actions on carbon dioxide emissions control in China. This paper explores the calculation method for carbon emissions of building materials products by taking rock wool sheet products as an example based on the life cycle idea and the characteristics of China's building materials industry. It also puts forward effective emission reduction suggestions through a comparative analysis of carbon emissions in different stages of rock wool production. The results show that the carbon emissions during the production of rock wool sheet is 1471.77 kgCO₂eq/t, in which, the proportion of carbon emissions in the raw materials production stage is the highest, accounting for 58%.

Abstract: This paper reports on a project for a senior citizens’ residence in the vicinity of Trento, Italy. The project constitutes the major part of a Master’s thesis in Architectural Engineering, developed at the University of Trento in Italy and at TU Vienna in Austria. The work entails a full account of environmental impacts during the life cycle of the building through LCA (Life Cycle Assessment). Furthermore, as buildings' end of life scenarios are insufficiently considered in most conventional LCA studies, the present contribution attempts to pursue a “cradle to cradle” approach (exploring a closed-loop flow of materials, energy, and resources) and to emphasize that the consequences of the choices made at the early stage of the design phase are critical for the subsequent stages of construction, use, maintenance, and end of life.The work consists of two parts. The first part relating to the architectural project involves careful consideration of the local characteristics of the site according to bioclimatic studies. In the second part, a comparative LCA study of different timber constructions and energy system options is presented, followed by a global LCA of the project. This aims at the estimation of the impacts of construction and end of life. Thereby, different possibilities are explored for reusing and recycling materials, such that disposal and incineration could be reduced as much as possible. Thus, the relative significance of different stages of the building construction, operation, and decommissioning can be explored.In conclusion, the paper offers a number of theoretical reflections on uncertainty analysis in LCA, addressing input assumptions (availability and quality of data) as well those regarding normalization and weighting factors. Thereby, the aim is to contribute to efforts toward a more pervasive application of the LCA methodology in the building design and delivery process.

Abstract: Resource consumption, energy consumption, environmental impact and costs of layer-combustion boiler were assessed by using life cycle assessment (LCA). The costs during construction stage, resource and energy consumption during operation stage of layer-combustion hot-water boiler were focused on. Life cycle inventory was established. The results show that: throughout the boiler life cycle, the largest resource consumption indicator is that of coal with value of 93%, followed by natural gas and limestone. For the internal costs, although operation costs are obviously higher than construction costs, the construction costs still account for more than 30%, which is related to the relatively short servicetime of layer-combustion heating boilers. For the external costs, global warming accounts for the highest proportion.

Abstract: In the analysis of life cycle cost (LCC) according to the usage of all-composite structure, this study verified that economic operating cost impact occurring during operation is more important component than simple purchase cost in the review based on various economic components. Namely, all-composite structure requires the highest production costs based on LCC analysis, but entire LCC and ecological impact in the socio-economic aspect are important variables and all-composite structure is clearly the optimum alternative.

Abstract: Substance flow analysis (SFA) is an established method to analyze the structure and characterization of resource flows or substance flows. Lanthanum (La) is an important type of light rare earth element, which is widely used in the fields of glass, luminescence, catalyst, agriculture, etc. This paper conducts a static SFA for lanthanum in China in 2002 and 2011, including different life cycle stages, e.g., exploitation, concentration, smelting, manufacture, use and disposal. Mining utilization efficiency, smelting ratio, export rate, ratio of scrap to raw material in 2002 and 2011 were comparatively analyzed. The results indicated that the utilization efficiency of La in the production stage of rare earth concentrates increased in 2011 relative to the value in 2002 by 80%, and the utilization efficiency of La in the manufacturing stage increased by 74%. The results also showed that although the mining utilization rate was increased, the resource efficiency was still low and how to increase the resource efficiency is a significant issue for Chinese rare earth industry. On the based of the results, some advices were also proposed, which will provide useful reference information for the green development of Chinese rare earth industry.

Abstract: The mechanical systems consist of assembled parts, between which diverse interactions take place. Tolerance analysis purpose is to study the effects of part geometric deviations on assembly functional requirements. In the current approaches from this field, the part geometrical deviations are toleranced without considering the evolution of the geometrical deviations during product exploitation. As consequence, between two parts identical as type but with different values of their geometrical features, inside the designed tolerance zones, any difference is made despite they might have significantly different life cycles or manufacturing costs. This paper presents a new conceptual approach concerning parts tolerance design, based on a new criterion, namely the dimensional quality, defined by two important features: life cycle and manufacturing cost. The main issue of this approach is the optimal relation between the manufacturing tolerance zones and the acceptable functional deviation domain. The new concept implementation is sampled in the case of an articulated arm.