1,721,005 research outputs found
MEASURING SALINITY WITHIN SHALLOW PIEZOMETERS: COMPARISON OF TWO FIELD METHODS
No full textThe objective of this study is to understand the validity of salinity vertical profiles collected from shallow piezometers that are not previously flushed. This study shows that salinity data collected from boreholes are only an average value along the entire screened section of the piezometer. In order to collect data that is representative for the salinity of the adjacent aquifer, a new monitoring strategy has been developed. This strategy includes measurement of the salinity at the top of the water table in an auger hole which is a shallow boreholes made with an handheld drill. This should be combined with measurements in piezometers that are first flushed to take out stagnant water. From the piezometers on can measure the average salinity of the screened part and the salinity at the bottom of the aquifer. . By using this monitoring strategy it is also possible to define where the piezometers screens are located if this is not known beforehand
The Indoor Environmental Quality: A TOPSIS-based approach with indirect elicitation of criteria weights
No full textThe Indoor Environmental Quality (IEQ) assessment is a hot topic both for designers of industrial buildings and for academics since it has been proven to affect workers’ productivity. Despite the advantages of indirect eliciting approaches, only direct eliciting is used in the literature to assign weights to the main risks included in the IEQ assessment, i.e., those referring to the thermal comfort, visual comfort, acoustic comfort and indoor air quality. In order to bridge this gap and in line with the drivers of the human-centric industrial revolution, we have developed an indirect eliciting approach based on logistic regression and integer optimization that indirectly derives the aforementioned weights per worker (i.e., individual weighting) on the basis of the overall comfort perceived by him/her in different reference scenarios. These weights are then used to compute a TOPSIS-based risk measure that maps the aggregated, individual and dynamic risks to which the worker is subjected over time. A real case study is used to validate our proposal. The achieved results highlight the superiority of our indirect eliciting approach compared to the Analytical Hierarchic Process in reconstructing the overall comfort perceived by workers, as well as that age plays a crucial role to assign weights to the main risks included in the IEQ
Sustainability of logistics infrastructures: operational and technological alternatives to reduce the impact on air quality
No full textModern ports are productive systems characterized by transport-type activities (of goods and people) and by activities typically related to the sectors of industry, construction, commerce and related services. Despite their fundamental role in the economic and social development of the local area, ports also have a negative impact on the environment. This paper analyses the effect on the air quality of a maritime container terminal by assessing the typical activities carried out there. Five scenarios were studied using an EMEP/EEE (2019) bottom-up air pollutant inventory approach and through air quality numerical simulations with the ADMS-5 model. Changes in the layout of where the activities are carried out, the use of cold ironing, and the use of LNG as a fuel are the scenarios compared with the "BASE" condition. The results highlighted the improved air quality due to each solution, demonstrating how the use of alternative fuels or the electrification of the docks reduces pollutants by more than 70-80%. Delocalizing some of the handling was found to have fewer benefits. Economic factors and the engagement of key stakeholders would seem to influence the diffusion of these solutions
A framework for sourcing of evaporation between saturated and unsaturated zone in bare soil condition
No full textSourcing subsurface evaporation (Ess) into groundwater (Eg) and unsaturated zone (Eu) components has received little scientific attention so far, despite its importance in water management and agriculture. We propose a novel sourcing framework, with its implementation in dedicated post-processing software called SOURCE (used along with the HYDRUS1D model), to study evaporation sourcing dynamics, define quantitatively “shallow” and “deep” water table conditions and test the applicability of water table fluctuation (WTF) and “bucket” methods for estimation of Eg and Eu separately. For the “shallow” and “deep” water table we propose Eg > 0.95Ess and Eg = 0 criteria, respectively. Assessment of the WTF method allowed sourcing of very small fluxes otherwise neglected by standard hydrological methods. Sourcing with SOURCE software was more accurate than the standard “bucket” method mainly because of greater flexibility in spatio-temporal discretization. This study emphasized the dry condition relevance of groundwater evaporation which should be analysed by applying coupled flow of heat, vapour and liquid water. Editor D. Koutsoyiannis; Associate editor S. Kana
Chapter 7: Indirect Land Use Change and Bio-based Products
No full textThis chapter provides insights into those mechanisms leading to undesirable land use changes associated with the expansion of all biologically-based products, thus including biofuels and bio-based materials. The chapter conducts a reconnaissance of the land use change effects which are climate relevant, reversible in the long run or irreversible and, in some cases, synergetic with climate change. It reviews the main causes and presents evidence, as an example, of indirect land use changes - still ongoing - due to the biofuel policy in the US. The analysis of thresholds and certification criteria in the Renewable Energy Directive (RED II) revealed that a major role will be played by certification schemes and methods of certification of low iLUC risk biomass. Causal-descriptive models are presented as an appropriate class of models to support certification schemes and a dynamic system model generated through the European H2020 project STAR-ProBio project, named SydiLUC, is introduced. The model can be applied to various categories of bio-based products and estimates the annual land expansion per functional unit of bio-based product as well as the risk associated with a specific production route, in line with the most recent regulatory measures
Barometric pressure influence on water table fluctuations in coastal aquifersof partially enclosed seas: An example from the Adriatic coast, Italy
No full textItaly) were recorded to characterize groundwater level response to sea level fluctuations. Tide-inducedfluctuations, atmospheric pressure loading and recharge from rainfall have all been recognized in themeasured water table changes. We also identified additional water table fluctuations that are not relatedto rain, atmospheric pressure or tides. We propose that these additional fluctuations are related to interactionof groundwater, seiche events and ‘inverted barometric effects’. Their amplitude is important, because at a distance of 70 m from the coast they have a magnitude of 0.07 m, whereas the local tide has a 1 m amplitude. Seiches are standing waves that create sea water fluxes which affect groundwater below the first row of dunes in the study area. We propose that this ‘inverted barometric effect’ is an important process in creating water fluxes in the coastal zone that may strongly affect the position and width of the mixing zone between salt and fresh water
Evaporation Through a Dry Soil Layer: Column Experiments
Full text linkModeling of water vapor transport through a dry soil layer (DSL), typically formed in the top soil during dry seasons in arid and semi-arid areas, is still problematic. Previous laboratory experiments in controlled environments showed that the only vapor transport process through the DSL is by Fick's law of diffusion. However, field experiments exhibited consistently higher evaporation rates than predicted by diffusion flow only. Some proposed reasons for the mismatch were: (a) daily cycles of condensation and evaporation in the DSL due to changes in solar radiation; (b) wind effects on air movement in the DSL; (c) atmospheric pressure fluctuations; (d) nonlinear influence of the DSL thickness on the evaporation process. To link the laboratory experiments with field observations, we performed soil column experiments in the laboratory with thick (>50 cm) DSL, and with different wind speeds, two radiative lamp schedules (continuous and 12 h daily cycles) and different thicknesses of DSL. Atmospheric pressure, air temperature and humidity were measured continuously. The results show that the evaporation rates observed are larger than those predicted by diffusion flow only. We found that it was possible to model the evaporation rates as a function of atmospheric pressure fluctuations. In conclusion, atmospheric pressure fluctuations can induce evaporation rates in DSL larger than estimated by diffusion flow only, possibly explaining the discrepancy between laboratory and field evaporation rates
Spare parts management with Additive Manufacturing (AM): a critical review
Full text linkAdditive Manufacturing (AM) is a promising technology for producing spare parts, due to the wide variety of forms and materials that can be used and their enhanced mechanical properties. Given these features and the low lead times compared to classical manufacturing (CM), AM is now being investigated for the management of spare parts. This literature stream is relatively new, with many works based on different hypotheses (e.g., the reliability of AM parts) and with different conclusions. This critical literature review provides practitioners with information on the models available, their findings, and their limitations. Further research directions are also identified
Indoor Environmental Quality (IEQ): A Comparison between TOPSIS- and PROMETHEE-Based Approaches for Indirect Eliciting of Category Weights
Full text linkIndoor Environmental Quality (IEQ) has received a great deal of attention in recent years due to the relationship between worker comfort and productivity. Many academics have studied IEQ from both a building design and an IEQ assessment perspective. This latter line of research has mostly used direct eliciting to obtain weights assigned to IEQ categories such as thermal comfort, visual comfort, acoustic comfort, and indoor air quality. We found only one application of indirect eliciting in the literature. Such indirect eliciting operates without the need for imprecise direct weighing and requires only comfort evaluations, which is in line with the Industry 5.0 paradigm of individual, dynamic, and integrated IEQ evaluation. In this paper, we use a case study to compare the only indirect eliciting model already applied to IEQ, based on TOPSIS, to an indirect eliciting method based on PROMETHEE and to a classical direct eliciting method (AHP). The results demonstrate the superiority of indirect eliciting in reconstructing individual preferences related to perceived global comfort
A human-machine learning curve for stochastic assembly line balancing problems
Full text linkThe Assembly Line Balancing Problem (ALBP) represents one of the most explored research topics in manufacturing. However, only a few contributions have investigated the effect of the combined abilities of humans and machines in order to reach a balancing solution. It is well-recognized that human beings learn to perform assembly tasks over time, with the effect of reducing the time needed for unitary tasks. This implies a need to re-balance assembly lines periodically, in accordance with the increased level of human experience. However, given an assembly task that is partially performed by automatic equipment, it could be argued that some subtasks are not subject to learning effects. Breaking up assembly tasks into human and automatic subtasks represents the first step towards more sophisticated approaches for ALBP. In this paper, a learning curve is introduced that captures this disaggregation, which is then applied to a stochastic ALBP. Finally, a numerical example is proposed to show how this learning curve affects balancing solutions
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