scholarly journals Emissions of Carbon Tetrachloride (CCl<sub>4</sub>) from Europe

2016 ◽  
Author(s):  
Francesco Graziosi ◽  
Jgor Arduini ◽  
Paolo Bonasoni ◽  
Francesco Furlani ◽  
Umberto Giostra ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Large Scale ◽  
Stratospheric Ozone ◽  
Montreal Protocol ◽  
Scale Production ◽  
Top Down ◽  
Significant Discrepancy ◽  
Bottom Up ◽  
Atmospheric Observations ◽  
Global Emissions

Abstract. Carbon tetrachloride (CCl4) is a long-lived radiatively-active compound able to destroy stratospheric ozone. Due to its inclusion in the Montreal Protocol on Substances that Deplete the Ozone Layer, the last two decades have seen a sharp decrease in its large scale emissive use with a consequent decline of its atmospheric mole fractions. However, the Montreal Protocol restrictions do not apply to the use of carbon tetrachloride as feedstock for the production of other chemicals, implying the risk of fugitive emissions from the industry sector. The occurrence of such unintended emissions is suggested by a significant discrepancy between global emissions as derived by reported production and feedstock usage (bottom-up emissions), and those based on atmospheric observations (top-down emissions). In order to better constrain the atmospheric budget of carbon tetrachloride, several studies based on a combination of atmospheric observations and inverse modelling have been conducted in recent years in various regions of the world. This study is focused on the European scale and based on long-term high-frequency observations at three European sites, combined with a Bayesian inversion methodology. We estimated that average European emissions for 2006–2014 were 2.3 (± 0.8) Gg yr−1, with an average decreasing trend of 7.3 % per year. Our analysis identified France as the main source of emissions over the whole study period, with an average contribution to total European emissions of 25 %. The inversion was also able to allow the localisation of emission "hot-spots" in the domain, with major source areas in Southern France, Central England (UK) and Benelux (Belgium, The Netherlands, Luxembourg), where most of industrial scale production of basic organic chemicals are located. According to our results, European emissions correspond to 4.0 % of global emissions for 2006–2012. Together with other regional studies, our results allow a better constraint of the global budget of carbon tetrachloride and a better quantification of the gap between top-down and bottom-up estimates.

scholarly journals Emissions of carbon tetrachloride from Europe

2016 ◽  
Vol 16 (20) ◽  
pp. 12849-12859 ◽  
Author(s):  
Francesco Graziosi ◽  
Jgor Arduini ◽  
Paolo Bonasoni ◽  
Francesco Furlani ◽  
Umberto Giostra ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Large Scale ◽  
Stratospheric Ozone ◽  
Montreal Protocol ◽  
Scale Production ◽  
Top Down ◽  
Significant Discrepancy ◽  
Bottom Up ◽  
Atmospheric Observations ◽  
Global Emissions

Abstract. Carbon tetrachloride (CCl4) is a long-lived radiatively active compound with the ability to destroy stratospheric ozone. Due to its inclusion in the Montreal Protocol on Substances that Deplete the Ozone Layer (MP), the last two decades have seen a sharp decrease in its large-scale emissive use with a consequent decline in its atmospheric mole fractions. However, the MP restrictions do not apply to the use of carbon tetrachloride as feedstock for the production of other chemicals, implying the risk of fugitive emissions from the industry sector. The occurrence of such unintended emissions is suggested by a significant discrepancy between global emissions as derived from reported production and feedstock usage (bottom-up emissions), and those based on atmospheric observations (top-down emissions). In order to better constrain the atmospheric budget of carbon tetrachloride, several studies based on a combination of atmospheric observations and inverse modelling have been conducted in recent years in various regions of the world. This study is focused on the European scale and based on long-term high-frequency observations at three European sites, combined with a Bayesian inversion methodology. We estimated that average European emissions for 2006–2014 were 2.2 (± 0.8) Gg yr−1, with an average decreasing trend of 6.9 % per year. Our analysis identified France as the main source of emissions over the whole study period, with an average contribution to total European emissions of approximately 26 %. The inversion was also able to allow the localisation of emission "hot spots" in the domain, with major source areas in southern France, central England (UK) and Benelux (Belgium, the Netherlands, Luxembourg), where most industrial-scale production of basic organic chemicals is located. According to our results, European emissions correspond, on average, to 4.0 % of global emissions for 2006–2012. Together with other regional studies, our results allow a better constraint of the global budget of carbon tetrachloride and a better quantification of the gap between top-down and bottom-up estimates.

scholarly journals Australian carbon tetrachloride emissions in a global context

2014 ◽  
Vol 11 (1) ◽  
pp. 77 ◽  
Author(s):  
Paul J. Fraser ◽  
Bronwyn L. Dunse ◽  
Alistair J. Manning ◽  
Sean Walsh ◽  
R. Hsiang J. Wang ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Environmental Concern ◽  
Stratospheric Ozone ◽  
Montreal Protocol ◽  
Global Network ◽  
Atmospheric Gases ◽  
Global Context ◽  
Production And Consumption ◽  
Atmospheric Observations ◽  
Using Data

Environmental context Carbon tetrachloride in the background atmosphere is a significant environmental concern, responsible for ~10% of observed stratospheric ozone depletion. Atmospheric concentrations of CCl4 are higher than expected from currently identified emission sources: largely residual emissions from production, transport and use. Additional sources are required to balance the expected atmospheric destruction of CCl4 and may contribute to a slower-than-expected recovery of the Antarctic ozone ‘hole’. Abstract Global (1978–2012) and Australian (1996–2011) carbon tetrachloride emissions are estimated from atmospheric observations of CCl4 using data from the Advanced Global Atmospheric Gases Experiment (AGAGE) global network, in particular from Cape Grim, Tasmania. Global and Australian emissions are in decline in response to Montreal Protocol restrictions on CCl4 production and consumption for dispersive uses in the developed and developing world. However, atmospheric data-derived emissions are significantly larger than ‘bottom-up’ estimates from direct and indirect CCl4 production, CCl4 transportation and use. Australian CCl4 emissions are not a result of these sources, and the identification of the origin of Australian emissions may provide a clue to the origin of some of these ‘missing’ global sources.

scholarly journals Process Variability in Top-Down Fabrication of Silicon Nanowire-Based Biosensor Arrays

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5153
Author(s):  
Marcel Tintelott ◽  
Vivek Pachauri ◽  
Sven Ingebrandt ◽  
Xuan Thang Vu
Keyword(s):  
Silicon Nanowires ◽  
Large Scale ◽  
Field Effect Transistors ◽  
State Of The Art ◽  
Silicon Nanowire ◽  
Limiting Factors ◽  
Scale Production ◽  
Top Down ◽  
Bottom Up ◽  
The Impact

Silicon nanowire field-effect transistors (SiNW-FET) have been studied as ultra-high sensitive sensors for the detection of biomolecules, metal ions, gas molecules and as an interface for biological systems due to their remarkable electronic properties. “Bottom-up” or “top-down” approaches that are used for the fabrication of SiNW-FET sensors have their respective limitations in terms of technology development. The “bottom-up” approach allows the synthesis of silicon nanowires (SiNW) in the range from a few nm to hundreds of nm in diameter. However, it is technologically challenging to realize reproducible bottom-up devices on a large scale for clinical biosensing applications. The top-down approach involves state-of-the-art lithography and nanofabrication techniques to cast SiNW down to a few 10s of nanometers in diameter out of high-quality Silicon-on-Insulator (SOI) wafers in a controlled environment, enabling the large-scale fabrication of sensors for a myriad of applications. The possibility of their wafer-scale integration in standard semiconductor processes makes SiNW-FETs one of the most promising candidates for the next generation of biosensor platforms for applications in healthcare and medicine. Although advanced fabrication techniques are employed for fabricating SiNW, the sensor-to-sensor variation in the fabrication processes is one of the limiting factors for a large-scale production towards commercial applications. To provide a detailed overview of the technical aspects responsible for this sensor-to-sensor variation, we critically review and discuss the fundamental aspects that could lead to such a sensor-to-sensor variation, focusing on fabrication parameters and processes described in the state-of-the-art literature. Furthermore, we discuss the impact of functionalization aspects, surface modification, and system integration of the SiNW-FET biosensors on post-fabrication-induced sensor-to-sensor variations for biosensing experiments.

“Forward to David the Builder!” Georgia's (re)turn to language-centered nationalism

2016 ◽  
Vol 44 (4) ◽  
pp. 522-542 ◽  
Author(s):  
Christofer Berglund
Keyword(s):  
Large Scale ◽  
Nation Building ◽  
The State ◽  
Top Down ◽  
Bottom Up ◽  
The Past ◽  
Building Project ◽  
The Rose ◽  
State Language

After the Rose Revolution, President Saakashvili tried to move away from the exclusionary nationalism of the past, which had poisoned relations between Georgians and their Armenian and Azerbaijani compatriots. His government instead sought to foster an inclusionary nationalism, wherein belonging was contingent upon speaking the state language and all Georgian speakers, irrespective of origin, were to be equals. This article examines this nation-building project from a top-down and bottom-up lens. I first argue that state officials took rigorous steps to signal that Georgian-speaking minorities were part of the national fabric, but failed to abolish religious and historical barriers to their inclusion. I next utilize a large-scale, matched-guise experiment (n= 792) to explore if adolescent Georgians ostracize Georgian-speaking minorities or embrace them as their peers. I find that the upcoming generation of Georgians harbor attitudes in line with Saakashvili's language-centered nationalism, and that current Georgian nationalism therefore is more inclusionary than previous research, or Georgia's tumultuous past, would lead us to believe.

scholarly journals Climate Dialog, Climate Action: Can Democracy Do the Job?

2021 ◽  
Author(s):  
Fred Young Phillips ◽  
LaVonne Reimer ◽  
Rebecca Turner
Keyword(s):  
Large Scale ◽  
Global Climate ◽  
Environmental Issues ◽  
Top Down ◽  
Bottom Up ◽  
Psychological Mechanisms ◽  
Ipcc Report ◽  
Climate Action

The latest IPCC report forcefully states that immediate, decisive, and large-scale actions are needed to avert climate catastrophe. This essay presumes that democratic governments are best and most desirably positioned to take these actions. Yet in the countries most pivotal to global climate, significant voting blocs are uninterested in environmental issues. The essay urges adding bottom-up dialog between environmental and anti-environmental voters, to current and future top-down technocratic &ldquo;solutions.&rdquo; To make this combination result in a unified pro-environment electorate, we must understand: religious objections to environmentalism; the capital-vs.-knowledge strife that slows polluting corporations&rsquo; green transitions; and the psychological mechanisms that can make inter-group dialog fruitful.

scholarly journals Trends and inter-annual variability of methane emissions derived from 1979-1993 global CTM simulations

2003 ◽  
Vol 3 (1) ◽  
pp. 73-88 ◽  
Author(s):  
F. Dentener ◽  
M. van Weele ◽  
M. Krol ◽  
S. Houweling ◽  
P. van Velthoven
Keyword(s):  
Transport Model ◽  
Meteorological Data ◽  
Stratospheric Ozone ◽  
Methane Emissions ◽  
Anthropogenic Emission ◽  
Top Down ◽  
Bottom Up ◽  
Annual Variability ◽  
The Difference ◽  
Ozone Precursor

Abstract. The trend and interannual variability of methane sources are derived from multi-annual simulations of tropospheric photochemistry using a 3-D global chemistry-transport model. Our semi-inverse analysis uses the fifteen years (1979--1993) re-analysis of ECMWF meteorological data and annually varying emissions including photo-chemistry, in conjunction with observed CH4 concentration distributions and trends derived from the NOAA-CMDL surface stations. Dividing the world in four zonal regions (45--90 N, 0--45 N, 0--45 S, 45--90 S) we find good agreement in each region between (top-down) calculated emission trends from model simulations and (bottom-up) estimated anthropogenic emission trends based on the EDGAR global anthropogenic emission database, which amounts for the period 1979--1993 2.7 Tg CH4 yr-1. Also the top-down determined total global methane emission compares well with the total of the bottom-up estimates. We use the difference between the bottom-up and top-down determined emission trends to calculate residual emissions. These residual emissions represent the inter-annual variability of the methane emissions. Simulations have been performed in which the year-to-year meteorology, the emissions of ozone precursor gases, and the stratospheric ozone column distribution are either varied, or kept constant. In studies of methane trends it is most important to include the trends and variability of the oxidant fields. The analyses reveals that the variability of the emissions is of the order of 8Tg CH4 yr-1, and likely related to wetland emissions and/or biomass burning.

Large scale and cost effective generation of 3D self-supporting oxide nanowire architectures by a top-down and bottom-up combined approach

RSC Advances ◽  
2016 ◽  
Vol 6 (51) ◽  
pp. 45923-45930 ◽  
Author(s):  
Peixun Fan ◽  
Minlin Zhong ◽  
Benfeng Bai ◽  
Guofan Jin ◽  
Hongjun Zhang
Keyword(s):  
Large Scale ◽  
Cost Effective ◽  
Combined Approach ◽  
Top Down ◽  
Bottom Up ◽  
Effective Generation

Large-scale and cost-effective generation of desired 3D self-supporting macro–micronano-nanowire architectures is realized by a top-down and bottom-up combined approach.

Distributional semantics insights on agentive suffix rivalry in French

2021 ◽  
Vol 14 (3) ◽  
pp. 354-391
Author(s):  
Richard Huyghe ◽  
Marine Wauquier
Keyword(s):  
Quantitative Analysis ◽  
Large Scale ◽  
Statistical Analyses ◽  
Distributional Semantics ◽  
Top Down ◽  
Bottom Up ◽  
Distributional Properties ◽  
Large Scale Study ◽  
New Perspective

The formation of French agent nouns (ANs) involves a large variety of morphological constructions, and particularly of suffixes. In this study, we focus on the semantic counterpart of agentive suffix diversity and investigate whether the morphological variety of ANs correlates with different agentive subtypes. We adopt a distributional semantics approach and combine manual, computational and statistical analyses applied to French ANs ending in -aire, -ant, -eur, -ien, -ier and -iste. Our methodology allows for a large-scale study of ANs and involves both top-down and bottom-up procedures. We first characterize agentive suffixes with respect to their morphosemantic and distributional properties, outlining their specificities and similarities. Then we automatically cluster ANs into distributionally relevant subsets and examine their properties. Based on quantitative analysis, our study provides a new perspective on agentive suffix rivalry in French that both confirms existing claims and sheds light on previously unseen phenomena.

Construction of a silicon-based solid state quantum computer

2001 ◽  
Vol 1 (Special) ◽  
pp. 82-95
Author(s):  
A.S. Dzurak ◽  
M.Y. Simmons ◽  
A.R. Hamilton ◽  
R.G. Clark ◽  
R. Brenner ◽  
...  
Keyword(s):  
Large Scale ◽  
Quantum Computer ◽  
Atomic Scale ◽  
Single Electron Transistor ◽  
Epitaxial Silicon ◽  
Top Down ◽  
Bottom Up ◽  
Near Term ◽  
Silicon Based ◽  
Coincidence Measurements

We discuss progress towards the fabrication and demonstration of a prototype silicon-based quantum computer. The devices are based on a precise array of 31P dopants embedded in 28Si. Fabrication is being pursued via two complementary pathways – a ‘top-down’ approach for near-term production of few-qubit demonstration devices and a ‘bottom-up’ approach for large-scale qubit arrays. The ‘top-down’ approach employs ion implantation through a multi-layer resist structure which serves to accurately register the donors to metal control gates and single-electron transistor (SET) read-out devices. In contrast the ‘bottom-up’ approach uses STM lithography and epitaxial silicon overgrowth to construct devices at an atomic scale. Techniques for qubit read-out, which utilise coincidence measurements on novel twin-SET devices, are also presented.

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