•Novel methodology to size capacity of wind farms under life cycle scope.•Improved Life Cycle Cost by increasing reliability and reducing Corrective Maintenance costs up to 18.48%.•Improved service ...level by increasing Availability of the Wind farm in up to 2.11%.•Reduced inefficiency costs due to unavailability up to 2.06%.•Improved efficiency of maintenance policies by potentially extending the time between failures.
Renewable energies are becoming the norm and as such they are responsible for the energy supply of large cities, therefore, there is a need for this energy sources to be able to deliver a determined level of service. The latter is especially complex for wind farms due to the high stress and rough climate conditions in which they operate. A higher service level is usually achieved by injecting budget on the operation of plants, namely, maintenance and asset management to reduce the risk of failure and outage. This article proposes a methodology to study the improvement of the service level, availability, and reliability of a plant from the design stage through oversizing the allocation of Wind Turbine Generators (WTG) without compromising the project Life Cycle Cost, indeed, results reveal up to a 2.11% of improvement on availability, a reduction of up to 18.48% on corrective maintenance costs and up to a 1.44% reduction of total differential costs. Furthermore, the evidence found suggests that the load sharing perspective imprints less stress on the WTG, enabling higher service levels at reduced costs and better results for maintenance and asset management planning, thus improving efficiency focussing on preventive maintenance and reliability improving.
In this article, we report on the design and implementation of a reportability tool using Microsoft Power BI embedded with Python script to assess opportunistic grouping schemes under a preventive ...maintenance policy. The reportability tool is based on specially developed indicators based on current maintenance standards for better implementation and considers a formerly developed grouping strategy with poor embedded performance indicators as an implementation case for the tool. Performance indicators were carefully developed considering a stochastic perspective when possible; this enables decisions to be influenced by risk assessment under a costs view. Reporting is focused on six maintenance sub-functions, enabling the decision maker to easily assess performance of any maintenance process, thereby improving the quality of decisions. The developed tool is a step forward for grouping (or any scheduling scheme) strategies due to its flexibility to be implemented in almost any case, enabling comparison between different grouping algorithms.
Wastewater treatment is a critical and necessary task every human settlement is obligated to address. If not, the consequences might be catastrophic, not just for humans but for the ecosystems as ...well, pushing research into finding new ways to improve wastewater treatment processes to make them safer and more efficient. Hence, there is a need to address matters, such as reliability and maintainability of Wastewater Treatment Plants (WWTP), when analyzing the availability and operational conditions. These should be addressed by analyzing the plant operational effectiveness impact (P-OEI), and in this article specifically, a WWTP study case to identify design flaws or improvement opportunities. A vital aspect of a complex system is to determine the contribution to resilience, reliability, and availability of every element embedded in the system. This is performed by adapting and applying the P-OEI methodology and real data of a WWTP located in Chile. This methodology breaks down the system into several levels of disaggregation similar to RBD methodology, analyzing the upstream for availability and the downstream for the P-OEI analysis from the system itself to the individual elements within subsystems. The potential impact on the overall system’s lack of efficiency is also quantified by an Expected Operational Impact (EOI) index, which is also calculated by the methodology. The P-OEI and EOI analyses performed in this study are powerful tools to assess the design and performance of complex systems and WWTP in particular.
The implementation of confinement and physical distancing measures to restrict people's activities and transit in the midst of the COVID-19 pandemic allowed us to study how these measures affect the ...air quality in urban areas with high pollution rates, such as Santiago, Chile. A comparative study between the concentrations of PM10, PM2.5, NOx, CO, and O3 during the months of March to May 2020 and the corresponding concentrations during the same period in 2017–2019 is presented. A combination of surface measurements from the air quality monitoring network of the city, remote satellite measurements, and simulations of traffic activity and road transport emissions allowed us to quantify the change in the average concentrations of each pollutant. Average relative changes of traffic emissions (between 61% and 68%) implied statistically significant concentrations reductions of 54%, 13%, and 11% for NOx, CO, and PM2.5, respectively, during the pandemic period compared to historical period. In contrast, the average concentration of O3 increased by 63% during 2020 compared to 2017–2019. The nonlinear response observed in the pollution levels can be attributed to the changes in the vehicular emission patterns during the pandemic and to the role of other sources such as residential emissions or secondary PM.
Display omitted
•Air pollutant concentrations were reduced during the COVID-19 lockdown, except for O3.•PM10, PM2.5, and CO concentrations dropped from 5% to 13% during the pandemic.•Up to 54% reductions were observed for NOx concentrations, while O3 concentrations increased by 63%.•Large relative changes in traffic emissions implied minor reductions in ambient PM levels.
This study delves into the photochemical atmospheric changes reported globally during the pandemic by analyzing the change in emissions from mobile sources and the contribution of local meteorology ...to ozone (O3) and particle formation in Bogotá (Colombia), Santiago (Chile), and São Paulo (Brazil). The impact of mobility reductions (50%–80%) produced by the early coronavirus-imposed lockdown was assessed through high-resolution vehicular emission inventories, surface measurements, aerosol optical depth and size, and satellite observations of tropospheric nitrogen dioxide (NO2) columns. A generalized additive model (GAM) technique was also used to separate the local meteorology and urban patterns from other drivers relevant for O3 and NO2 formation. Volatile organic compounds, nitrogen oxides (NOx), and fine particulate matter (PM2.5) decreased significantly due to motorized trip reductions. In situ nitrogen oxide median surface mixing ratios declined by 70%, 67%, and 67% in Bogotá, Santiago, and São Paulo, respectively. NO2 column medians from satellite observations decreased by 40%, 35%, and 47%, respectively, which was consistent with the changes in mobility and surface mixing ratio reductions of 34%, 25%, and 34%. However, the ambient NO2 to NOx ratio increased, denoting a shift of the O3 formation regime that led to a 51%, 36%, and 30% increase in the median O3 surface mixing ratios in the 3 respective cities. O3 showed high sensitivity to slight temperature changes during the pandemic lockdown period analyzed. However, the GAM results indicate that O3 increases were mainly caused by emission changes. The lockdown led to an increase in the median of the maximum daily 8-h average O3 of between 56% and 90% in these cities.
This study presents the first high-resolution national inventory
of anthropogenic emissions for Chile (Inventario Nacional de Emisiones Antropogénicas, INEMA). Emissions for the vehicular, ...industrial, energy, mining and residential sectors are estimated for the
period 2015–2017 and spatially distributed onto a high-resolution grid (approximately 1 km×1 km). The pollutants included are CO2, NOx, SO2,
CO, VOCs (volatile organic compounds), NH3 and particulate matter (PM10 and PM2.5) for
all sectors. CH4 and black carbon are included for transport and
residential sources, while arsenic, benzene, mercury, lead, toluene, and
polychlorinated dibenzo-p-dioxins and furan (PCDD/F) are estimated for
energy, mining and industrial sources. New activity data and emissions
factors are compiled to estimate emissions, which are subsequently spatially
distributed using census data and Chile's road network
information. The estimated annual average total national emissions of PM10 and
PM2.5 during the study period are 191 and 173kt a−1 (kilotons per year),
respectively. The residential sector is responsible for over 90 % of these
emissions. This sector also emits 81 % and 87 % of total CO and VOC,
respectively. On the other hand, the energy and industry sectors contribute
significantly to NH3, SO2 and CO2 emissions, while the transport
sector dominates NOx and CO2 emissions, and the mining sector dominates
SO2 emissions. In general, emissions of anthropogenic air pollutants
and CO2 in northern Chile are dominated by mining activities as well as
thermoelectric power plants, while in central Chile the dominant sources are
transport and residential emissions. The latter also mostly dominates
emissions in southern Chile, which has a much colder climate. Preliminary
analysis revealed the dominant role of the emission factors in the final
emission uncertainty. Nevertheless, uncertainty in activity data also
contributes as suggested by the difference in CO2 emissions between
INEMA and EDGAR (Emission Database for Global Atmospheric Research). A comparison between these two inventories also revealed
considerable differences for all pollutants in terms of magnitude and
sectoral contribution, especially for the residential sector. EDGAR presents
larger emissions for most of the pollutants except for CH4 and
PM2.5. The differences between both inventories can partly be
explained by the use of different emission factors, in particular for the
residential sector, where emission factors incorporate information on
firewood and local operation conditions. Although both inventories use
similar emission factors, differences in CO2 emissions between both
inventories indicate biases in the quantification of the activity. This inventory (available at https://doi.org/10.5281/zenodo.4784286, Alamos et al., 2021) will
support the design of policies that seek to mitigate climate change and
improve air quality by providing policymakers, stakeholders and scientists
with qualified scientific spatially explicit emission information.
This description paper presents a detailed and consistent estimate and
analysis of exhaust pollutant emissions generated by Chile's
road transport activity for the period 1990–2020. The complete ...database for
the period 1990–2020 is available at the following DOI:
https://doi.org/10.17632/z69m8xm843.2 (Osses et al., 2021). Emissions are
provided at a high spatial resolution (0.01∘ × 0.01∘) over continental Chile from 18.5 to 53.2∘ S,
including local pollutants (CO; volatile organic compounds, VOCs; NOx; PM2.5), black carbon (BC) and
greenhouse gases (CO2, CH4). The methodology considers 70 vehicle
types, based on 10 vehicle categories, subdivided into 2 fuel types and
7 emission standards. Vehicle activity was calculated based on official
databases of vehicle records and vehicle flow counts. Fuel consumption was
calculated based on vehicle activity and contrasted with fuel sales to
calibrate the initial dataset. Emission factors come mainly from the Computer programme to calculate emissions from road
transport version 5 (COPERT 5),
adapted to local conditions in the 15 political regions of Chile, based on
emission standards and fuel quality. While vehicle fleet grew 5-fold
between 1990 and 2020, CO2 emissions have followed this trend at a
lower rate, and emissions of air local pollutants have decreased due to
stricter abatement technologies, better fuel quality and enforcement of
emission standards. In other words, there has been decoupling between fleet
growth and emissions' rate of change. Results were contrasted with global
datasets (EDGAR, CAMS, CEDS), showing similarities in CO2 estimations
and striking differences in PM, BC and CO; in the case of NOx and CH4
there is coincidence only until 2008. In all cases of divergent results,
global datasets estimate higher emissions.
This study delves into the photochemical atmospheric changes reported globally during the pandemic by analyzing the change in emissions from mobile sources and the contribution of local meteorology ...to ozone (O3) and particle formation in Bogotá (Colombia), Santiago (Chile), and São Paulo (Brazil). The impact of mobility reductions (50%–80%) produced by the early coronavirus-imposed lockdown was assessed through high-resolution vehicular emission inventories, surface measurements, aerosol optical depth and size, and satellite observations of tropospheric nitrogen dioxide (NO2) columns. A generalized additive model (GAM) technique was also used to separate the local meteorology and urban patterns from other drivers relevant for O3 and NO2 formation. Volatile organic compounds, nitrogen oxides (NOx), and fine particulate matter (PM2.5) decreased significantly due to motorized trip reductions. In situ nitrogen oxide median surface mixing ratios declined by 70%, 67%, and 67% in Bogotá, Santiago, and São Paulo, respectively. NO2 column medians from satellite observations decreased by 40%, 35%, and 47%, respectively, which was consistent with the changes in mobility and surface mixing ratio reductions of 34%, 25%, and 34%. However, the ambient NO2 to NOx ratio increased, denoting a shift of the O3 formation regime that led to a 51%, 36%, and 30% increase in the median O3 surface mixing ratios in the 3 respective cities. O3 showed high sensitivity to slight temperature changes during the pandemic lockdown period analyzed. However, the GAM results indicate that O3 increases were mainly caused by emission changes. The lockdown led to an increase in the median of the maximum daily 8-h average O3 of between 56% and 90% in these cities.
This study contributes to the limited body of research concerned with documenting and studying the minority and indigenous languages of the world. More specifically, it focuses on Kamënts̈á, a ...language isolate spoken by less than 500 people in southern Colombia. According to UNESCO (2003), this language has been categorized as “definitely endangered” which makes its documentation even more critical. Although there have been initial investigations undertaken by Juajibioy, Howard, and McDowell, the scarce accessible research has relied on purely impressionistic reviews of the language, leading to unreliable conclusions and descriptions of the language. This thesis constitutes the first phonetic acoustic analysis of Kamënts̈á language in order to substantiate what has been described in the current literature. Additionally, the geographic location where Kamënts̈á emerged, together with Spanish, and Inga Kichwa has proven to be an intriguing sociohistorical and linguistic landscape for the study of these languages being an area worth of investigating. Given that there is no existing documentation of language variation in the language, the primary goal of this thesis is to analyze the production of plosive and affricate segments at a word-level to examine language variation at a phonetic level. Considering that Kamënts̈á has been poorly documented, it was not surprising for differences in the production to be found. One difference fell in the phonemic status of the segment between younger and older speakers of the language. The production of the segments in three linguistic environments at word-level attested for variation of some phonemes. For this study, data were collected from two experimental tasks. For the first task, eight Kamënts̈á-Spanish bilinguals (N = 8) were recorded producing words in isolation in a word-elicitation exercise. The purpose of this task was to gather raw data on the production of the segments at word level. For the second task, the consultants were asked to take a sociolinguistic questionnaire. This instrument was designed to account for the linguistic ethnography and language ecology of the Kamënts̈á. The purpose of this task was also to tie sociolinguistic data from the speakers with any phonemic differences in the realization of the segments. Results supported the VOT framework proposed by Lisker and Abramson (1964) as an effective metric to measure the voicing status of plosives. For the analysis of affricates, the center of gravity and spectral peak location demonstrated accurate acoustic correlates to capture frication in the phonemes. Equally, amplitude provided valuable information for the analysis of prenasalization. What is more, consistent resemblances were found comparing Kamënts̈á with other studies regarding the acoustic cues, place and manner of articulation, and voicing status of the phonemes.
Informe de Seminario para optar al grado de Licenciado en Historia
Seminario de grado: Procesos políticos y postmemorias autoritarias. Chile en la segunda mitad del siglo XX
PDF
