Benefitting from the continuous innovations in semiconductor materials and device fabricating techniques, ultraviolet (UV) photodetectors have been successfully used in advanced communications, flame ...detection, air purification, ozone sensing and leak detection, among others, in the past few decades. Nowadays, nanoscience, nanofabrication technologies and versatile materials have sparked a new vision of UV photodetectors, which move toward higher precision, lower energy consumption and greater miniaturization. This paper is thus mainly focused on the perspective of molding devices through exploring new materials and novel architectures inspired by state-of-the-art UV photodetectors, predicting the direction of next-generation photodetectors. It is expected that new concept UV photodetectors with smart, intelligent and multifunctional design will benefit daily life and the well-being of society in the near future.
Ethylenediurea (EDU) has been widely studied for its effectiveness to protect plants against injuries caused by surface ozone (O3), however its mode of action remains unclear. So far, there is not a ...unified methodological approach and thus the methodology is quite arbitrary, thereby making it more difficult to generalize findings and understand the EDU mode of action. This review examines the question of whether potential N addition to plants by EDU is a fundamental underlying mechanism in protecting against O3 phytotoxicity. Yet, this review proposes an evidence-based hypothesis that EDU may protect plants against O3 deleterious effects upon generation of EDU-induced hormesis, i.e. by activating plant defense at low doses. This hypothesis challenges the future research directions. Revealing a hormesis-based EDU mode of action in protecting plants against O3 toxicity would have further implications to ecotoxicology and environmental safety. Furthermore, this review discusses the need for further studies on plant metabolism under EDU treatment through relevant experimental approach, and attempts to set the bases for approaching a unified methodology that will contribute in revealing the EDU mode of action. In this framework, focus is given to the main EDU application methods.
Display omitted
•Ethylenediurea (EDU) is a chemical compound that protects plants against O3 injury.•EDU mode of action in plants has not been revealed yet.•This article proposes a potential hormesis-based EDU mode of action.•Such a potential mode of action would have implications to environmental safety.
As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of Mexico maintained by the National Institute of Ecology and Climate Change ...(INECC) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range from 0 nmol/mol to 500 nmol/mol.
Main text
To reach the main text of this paper, click on
Final Report
. Note that this text is that which appears in Appendix B of the BIPM key comparison database
kcdb.bipm.org/
.
The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
As part of the on-going key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of Croatia maintained by the Meteorological and Hydrological Service (DHMZ) and ...the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM), via a transfer standard maintained by the National Institute of Standards and Technology (NIST). The instruments have been compared over a nominal ozone amount-of-substance fraction range of 0 nmol/mol to 500 nmol/mol.
KEY WORDS FOR SEARCH
Ozone, Standard Reference Photometer, BIPM, DHMZ, CIPM MRA, KCDB
Main text
To reach the main text of this paper, click on
Final Report
. Note that this text is that which appears in Appendix B of the BIPM key comparison database
kcdb.bipm.org/
.
The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of Finland maintained by the Finnish Meteorological Institute (FMI) and the ...common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range from 0 nmol/mol to 500 nmol/mol.
KEY WORDS FOR SEARCH
Ozone, Standard Reference Photometer, BIPM, FMI, KCDB, CIPM MRA
Main text
To reach the main text of this paper, click on
Final Report
. Note that this text is that which appears in Appendix B of the BIPM key comparison database
kcdb.bipm.org/
.
The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of India maintained by the CSIR-National Physical Laboratory, India (NPLI) and ...the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range from 0 nmol/mol to 500 nmol/mol.
KEY WORDS FOR SEARCH
Ozone, Standard Reference Photometer
Main text
To reach the main text of this paper, click on
Final Report
. Note that this text is that which appears in Appendix B of the BIPM key comparison database
kcdb.bipm.org/
.
The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone standard of the United Kingdom maintained by the National Physical Laboratory (NPL) and the common ...reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range of 0 nmol/mol to 500 nmol/mol.
Main text
To reach the main text of this paper, click on
Final Report
. Note that this text is that which appears in Appendix B of the BIPM key comparison database
kcdb.bipm.org/
.
The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Display omitted
•Ozone oxidation coupled with post-absorption is firstly reviewed for flue gas treatment.•Simultaneous removal of NOx, SO2, VOCs, and mercury can be achieved by this ...technology.•Solubility increase and bond breaking are basic principles for pollutants removal by ozone.•This technology is potential to attain ultra-low emission for industrial boiler and furnaces.
Traditional flue gas pollutants treatment technologies are installed with their individual function. Industries usually make simple combination and increase operation load of equipment to face with the increasing stringent environmental stress and emission standard. Especially, these technique routes are not available to industrial boilers and furnaces because of specific conditions, such as unsuitable temperature window, complicated components in flue gas, and flexible operation. Simultaneous removal of multi-pollutants within one or two devices is a prospective direction that can save space occupation and cost. Interestingly, the solubility of NOx and mercury increases with its valance state, and organic pollutants can be degraded into nontoxic small molecules by oxidation. Ozone is a strong gas phase oxidant that can achieve pre-oxidation at low temperature, following by post-absorption to completely remove oxidized products. This review focuses on research progress involved in homogeneous and heterogeneous catalytic oxidation of NOx, organic pollutants, and mercury by ozone, as well as NOx absorption regarding of its full path removal. The reaction mechanism, kinetics, operation parameters, conversion efficiency and ozone residual are all summarized in detail. This paper also systematically reviews various approaches in catalytic ozonation towards improving catalytic activity, selectivity, and stability, as well as lowering temperature, such as active metals, metal loading contents, supports, precursors, and other modification. Finally, the overall technique route of simultaneous removal of multi-pollutants by ozone is analyzed. In conclusion, the ozone oxidation technology is advantaged in flue gas pollutants treatment, including low temperature, no massive adjustment in operation and original devices, saving space, no secondary pollution, N/S sources recovery, and potential to ultra-low emission.
Display omitted
•Hydroxyl and sulfate radical related AOPs at basic pH were reviewed.•Studies of model and real wastewater were discussed, with emphasis to real effluents.•The studies of degradation ...pathways and by-products were reviewed.•Economical evaluation of the processes was discussed.•Good practice for planning the research is described.
Advanced oxidation processes (AOPs) have been used as an alternative and effective option for treatment of industrial wastewater, especially in the case of the non-biodegradable compounds. Despite of several well developed AOPs, the majority of them are effective only at acidic or neutral pH, namely Fenton related processes, making the list of available effective advanced oxidation technologies strongly limited. In many cases, industrial effluents are formed at basic pH conditions. This paper reviews the state of the art of AOPs exclusively at alkaline pH, the type of compounds and effluents effectively degraded, the influence of pH on the efficiency of the processes, economic evaluation and degradation pathways. Spent caustic, polyester and acetate fiber dye effluents, phenol, acidic and sulfur based compounds, specific dyes and drugs were effectively degraded at basic pH. Factors like point of zero charge, pKa of the compounds, amount of radicals produced and activation of the oxidants are crucial factors that affect the treatment efficiency of AOPs at basic pH. H2O2 and O3 were the cheapest processes while peroxone was the most expensive. The treatment costs were in general too expensive and unrealistic using the methodology used in the literature. The alternative methodology proposed in this paper reduced the treatment costs by three orders of magnitude to values more realistic and economical feasible. Literature regarding treatment of real effluents using AOPs at basic pH is scarce and further research is needed to perform complete analysis. It is important to present some alternatives regarding the treatment of alkaline effluents without pH correction using such technologies.
A gap in emission inventories of urban volatile organic compound (VOC) sources, which contribute to regional ozone and aerosol burdens, has increased as transportation emissions in the United States ...and Europe have declined rapidly. A detailed mass balance demonstrates that the use of volatile chemical products (VCPs)-including pesticides, coatings, printing inks, adhesives, cleaning agents, and personal care products-now constitutes half of fossil fuel VOC emissions in industrialized cities. The high fraction of VCP emissions is consistent with observed urban outdoor and indoor air measurements. We show that human exposure to carbonaceous aerosols of fossil origin is transitioning away from transportation-related sources and toward VCPs. Existing U.S. regulations on VCPs emphasize mitigating ozone and air toxics, but they currently exempt many chemicals that lead to secondary organic aerosols.
PDF
