scholarly journals Stabilization of CCA-contaminated soil with iron products - a field experiment

2019 ◽  
pp. 395-404
Author(s):  
Christian Maurice ◽  
Björn Gustavsson ◽  
Jurate Kumpiene ◽  
Sofia Lidelöw
Keyword(s):  
Contaminated Soil ◽  
Large Scale ◽  
Arsenic Content ◽  
Treatment Efficiency ◽  
Untreated Soil ◽  
Scale Reduction ◽  
Reducing Conditions ◽  
Wood Impregnation ◽  
Key Issues ◽  
Arsenic Leaching

Chemical stabilization of metals is lately considered as a possible pretreatment for soilcontaminated with average levels of trace elements. The element mobility in soil can bealtered by adding soil amendments that can adsorb, complex, or co-precipitate trace elements.As a consequence, pollutant spreading from the contaminated soil and effect on the recipientcan be reduced. The different contaminants originating from wood impregnation chemicals,e.g. Cu, Cr, and As limit the choice of amendments because e.g. large pH fluctuations andconsequent mobilization of Cu or As should be avoided. The results show that the leaching ofarsenic is lowest in the lysimeter with 15% Fe3O4. In both lysimeters with untreated soil andwith 1 % Fe 0, the arsenic leaching seems to decrease with the sampling depth. The leaching ofcopper is generally low. Further the addition of iron seems to increase the leaching ofmanganese and nickel but to reduce the leaching of zinc. Results from the laboratoryexperiment show that the arsenic content in the leachate is lowest with the highest mixture ofmagnetite. Mixing is one of the key issues when discussing the treatment efficiency andpossible use of the treated soil. The results so far indicate that magnetite can be used fortreatment of CCA contaminated soil also at a large scale. Reduction of both arsenic andcopper using a single amendment is challenging as they behave opposite. Magnetite seems tobe a promising amendment even though a high amount of amendment needs to be added.Moreover, the potential establishment of reducing conditions at larger depths in the soil is ofconcern since this might lead to a rapid increase in arsenic leaching

scholarly journals Clinician checklist for assessing suitability of machine learning applications in healthcare

2021 ◽  
Vol 28 (1) ◽  
pp. e100251
Author(s):  
Ian Scott ◽  
Stacey Carter ◽  
Enrico Coiera
Keyword(s):  
Machine Learning ◽  
Large Scale ◽  
Clinical Decision Making ◽  
Improve Patient Care ◽  
Clinical Decision ◽  
Routine Care ◽  
Machine Learning Algorithms ◽  
Clinical Settings ◽  
Machine Learning Applications ◽  
Key Issues

Machine learning algorithms are being used to screen and diagnose disease, prognosticate and predict therapeutic responses. Hundreds of new algorithms are being developed, but whether they improve clinical decision making and patient outcomes remains uncertain. If clinicians are to use algorithms, they need to be reassured that key issues relating to their validity, utility, feasibility, safety and ethical use have been addressed. We propose a checklist of 10 questions that clinicians can ask of those advocating for the use of a particular algorithm, but which do not expect clinicians, as non-experts, to demonstrate mastery over what can be highly complex statistical and computational concepts. The questions are: (1) What is the purpose and context of the algorithm? (2) How good were the data used to train the algorithm? (3) Were there sufficient data to train the algorithm? (4) How well does the algorithm perform? (5) Is the algorithm transferable to new clinical settings? (6) Are the outputs of the algorithm clinically intelligible? (7) How will this algorithm fit into and complement current workflows? (8) Has use of the algorithm been shown to improve patient care and outcomes? (9) Could the algorithm cause patient harm? and (10) Does use of the algorithm raise ethical, legal or social concerns? We provide examples where an algorithm may raise concerns and apply the checklist to a recent review of diagnostic imaging applications. This checklist aims to assist clinicians in assessing algorithm readiness for routine care and identify situations where further refinement and evaluation is required prior to large-scale use.

scholarly journals Large-scale reduction of tyrosine kinase activities in human monocytes stimulated in vitro with N. meningitidis

PLoS ONE ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. e0181912 ◽  
Author(s):  
Unni Gopinathan ◽  
Kathrine Røe Redalen ◽  
Anne-Marie Trøseid ◽  
Peter Kierulf ◽  
Petter Brandtzaeg ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Large Scale ◽  
Human Monocytes ◽  
Scale Reduction

scholarly journals Measurement of flow velocity profiles in tank structures using the prototype device OCM Pro LR

2011 ◽  
Vol 64 (1) ◽  
pp. 263-270 ◽  
Author(s):  
K. Klepiszewski ◽  
M. Teufel ◽  
S. Seiffert ◽  
E. Henry
Keyword(s):  
Flow Velocity ◽  
Large Scale ◽  
Fluid Dynamic ◽  
Waste Water Treatment ◽  
Transport Processes ◽  
Treatment Efficiency ◽  
Cleaning Efficiency ◽  
Cfd Modelling ◽  
Ultrasonic Signals ◽  
Cfd Models

Generally, studies investigating the treatment efficiency of tank structures for storm water or waste water treatment observe pollutant flows in connection with conditions of hydraulic loading. Further investigations evaluate internal processes in tank structures using computational fluid dynamic (CFD) modelling or lab scale tests. As flow paths inside of tank structures have a considerable influence on the treatment efficiency, flow velocity profile (FVP) measurements can provide a possibility to calibrate CFD models and contribute to a better understanding of pollutant transport processes in these structures. This study focuses on tests carried out with the prototype FVP measurement device OCM Pro LR by NIVUS in a sedimentation tank with combined sewer overflow (CSO) situated in Petange, Luxembourg. The OCM Pro LR measurement system analyses the echo of ultrasonic signals of different flow depths to get a detailed FVP. A comparison of flow velocity measured by OCM Pro LR with a vane measurement showed good conformity. The FVPs measured by OCM Pro LR point out shortcut flows within the tank structure during CSO events, which could cause a reduction of the cleaning efficiency of the structure. The results prove the applicability of FVP measurements in large-scale structures.

scholarly journals From lithium to sodium: cell chemistry of room temperature sodium–air and sodium–sulfur batteries

2015 ◽  
Vol 6 ◽  
pp. 1016-1055 ◽  
Author(s):  
Philipp Adelhelm ◽  
Pascal Hartmann ◽  
Conrad L Bender ◽  
Martin Busche ◽  
Christine Eufinger ◽  
...  
Keyword(s):  
Energy Density ◽  
Large Scale ◽  
Room Temperature ◽  
Low Cost ◽  
Strong Impact ◽  
Performance Improvements ◽  
Key Issues ◽  
Lithium Oxygen Batteries ◽  
Open Question ◽  
Lithium Sulfur

Research devoted to room temperature lithium–sulfur (Li/S8) and lithium–oxygen (Li/O2) batteries has significantly increased over the past ten years. The race to develop such cell systems is mainly motivated by the very high theoretical energy density and the abundance of sulfur and oxygen. The cell chemistry, however, is complex, and progress toward practical device development remains hampered by some fundamental key issues, which are currently being tackled by numerous approaches. Quite surprisingly, not much is known about the analogous sodium-based battery systems, although the already commercialized, high-temperature Na/S8 and Na/NiCl2 batteries suggest that a rechargeable battery based on sodium is feasible on a large scale. Moreover, the natural abundance of sodium is an attractive benefit for the development of batteries based on low cost components. This review provides a summary of the state-of-the-art knowledge on lithium–sulfur and lithium–oxygen batteries and a direct comparison with the analogous sodium systems. The general properties, major benefits and challenges, recent strategies for performance improvements and general guidelines for further development are summarized and critically discussed. In general, the substitution of lithium for sodium has a strong impact on the overall properties of the cell reaction and differences in ion transport, phase stability, electrode potential, energy density, etc. can be thus expected. Whether these differences will benefit a more reversible cell chemistry is still an open question, but some of the first reports on room temperature Na/S8 and Na/O2 cells already show some exciting differences as compared to the established Li/S8 and Li/O2 systems.

scholarly journals Advances in the automated synthesis of 6-[18F]Fluoro-L-DOPA

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Ângela C. B. Neves ◽  
Ivanna Hrynchak ◽  
Inês Fonseca ◽  
Vítor H. P. Alves ◽  
Mariette M. Pereira ◽  
...  
Keyword(s):  
Large Scale ◽  
Neuroendocrine Tumours ◽  
Radiochemical Yield ◽  
Clinical Applications ◽  
Clinical Use ◽  
Molar Activity ◽  
Neuropsychiatric Diseases ◽  
Recent Developments ◽  
Key Issues ◽  
Improved Methods

AbstractThe neurotracer 6-[18F] FDOPA has been, for many years, a powerful tool in PET imaging of neuropsychiatric diseases, movement disorders and brain malignancies. More recently, it also demonstrated good results in the diagnosis of other malignancies such as neuroendocrine tumours, pheochromocytoma or pancreatic adenocarcinoma.The multiple clinical applications of this tracer fostered a very strong interest in the development of new and improved methods for its radiosynthesis. The no-carrier-added nucleophilic 18F-fluorination process has gained increasing attention, in recent years, due to the high molar activities obtained, when compared with the other methods although the radiochemical yield remains low (17–30%). This led to the development of several nucleophilic synthetic processes in order to obtain the product with molar activity, radiochemical yield and enantiomeric purity suitable for human PET studies.Automation of the synthetic processes is crucial for routine clinical use and compliance with GMP requirements. Nevertheless, the complexity of the synthesis makes the production challenging, increasing the chance of failure in routine production. Thus, for large-scale clinical application and wider use of this radiopharmaceutical, progress in the automation of this complex radiosynthesis is of critical importance.This review summarizes the most recent developments of 6-[18F]FDOPA radiosynthesis and discusses the key issues regarding its automation for routine clinical use.

How can an economic scenario generation model cope with abrupt changes in financial markets?

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yi-Hsi Lee ◽  
Ming-Hua Hsieh ◽  
Weiyu Kuo ◽  
Chenghsien Jason Tsai
Keyword(s):  
Financial Markets ◽  
Large Scale ◽  
Moving Average ◽  
Insurance Companies ◽  
Scenario Generation ◽  
Autoregressive Moving Average ◽  
Generation Model ◽  
Content Type ◽  
Abrupt Changes ◽  
Key Issues

PurposeIt is quite possible that financial institutions including life insurance companies would encounter turbulent situations such as the COVID-19 pandemic before policies mature. Constructing models that can generate scenarios for major assets to cover abrupt changes in financial markets is thus essential for the financial institution's risk management.Design/methodology/approachThe key issues in such modeling include how to manage the large number of risk factors involved, how to model the dynamics of chosen or derived factors and how to incorporate relations among these factors. The authors propose the orthogonal ARMA–GARCH (autoregressive moving-average–generalized autoregressive conditional heteroskedasticity) approach to tackle these issues. The constructed economic scenario generation (ESG) models pass the backtests covering the period from the beginning of 2018 to the end of May 2020, which includes the turbulent situations caused by COVID-19.FindingsThe backtesting covering the turbulent period of COVID-19, along with fan charts and comparisons on simulated and historical statistics, validates our approach.Originality/valueThis paper is the first one that attempts to generate complex long-term economic scenarios for a large-scale portfolio from its large dimensional covariance matrix estimated by the orthogonal ARMA–GARCH model.

Impacts of Changing Operational Parameters of In Situ Chemical Oxidation (ISCO) on Removal of Aged PAHs from Soil

2012 ◽  
Vol 15 (2) ◽  
Author(s):  
Paula Cajal-Mariñosa ◽  
Ruth G. de la Calle ◽  
F. Javier Rivas ◽  
Tuula Tuhkanen
Keyword(s):  
Hydrogen Peroxide ◽  
Removal Efficiency ◽  
Contaminated Soil ◽  
Chemical Oxidation ◽  
Contaminant Removal ◽  
Operational Parameters ◽  
In Situ Chemical Oxidation ◽  
Different Types ◽  
Wood Impregnation

AbstractThe removal efficiency of two different types of peroxide addition, catalyzed hydrogen peroxide (CHP) and sodium percarbonate (SPC) were compared on a highly PAH-contaminated soil from a wood impregnation site. In an attempt to simulate real in situ reagents delivery, experiments have been carried out in acrylic columns. The main parameters affecting contaminant removal were the reagent’s temperature and the total addition of peroxide (g

scholarly journals Review of Early instructed second language acquisition: Pathways to competence; Editors: Joanna Rokita-Jaśkow, Melanie Ellis; Publisher: Multilingual Matters, 2019; ISBN: 9781788922494; Pages: 257

2019 ◽  
Vol 9 (4) ◽  
pp. 737-744
Author(s):  
Paweł Scheffler
Keyword(s):  
Second Language ◽  
Second Language Acquisition ◽  
Language Acquisition ◽  
Large Scale ◽  
Special Educational Needs ◽  
Teachers Perceptions ◽  
Instructed Second Language Acquisition ◽  
Key Issues ◽  
Large Scale Survey ◽  
Teaching Grammar

In a large scale survey of teachers’ perceptions of the challenges they face in teaching English to young primary school learners (Copland, Garton, & Burns, 2014), some of the key issues that are identified are as follows: teaching speaking, using only English in the classroom, enhancing motivation, maintaining discipline, catering for different individual needs (including special educational needs), dealing with parents, and teaching grammar as well as reading and writing. The relevance of Early Instructed Second Language Acquisition, edited by Rokita-Jaśkow and Ellis, is clearly shown by the fact that it addresses most of these central issues.

Nuclear fission

2007 ◽  
Author(s):  
Sue Ion
Keyword(s):  
Energy Supply ◽  
Nuclear Power ◽  
Large Scale ◽  
Nuclear Reactor ◽  
Nuclear Fission ◽  
Fuel Rods ◽  
Power Stations ◽  
Key Issues ◽  
Burning Coal ◽  
Hollow Metal

This chapter will cover the nuclear fission option as a future energy supply, and will essentially address the question: can nuclear fission plug the gap until the potential of nuclear fusion is actually realized? (The potential for fusion is considered in detail chapter 7.) To put this question into context, let us first look at some of the key issues associated with nuclear fission, which currently supplies around one fifth of the UK’s electricity. Most large scale power stations produce electricity by generating steam, which is used to power a turbine. In a nuclear power station, the principle is the same, but instead of burning coal, oil, or gas to turn water into steam, the heat energy comes from a nuclear reactor. A reactor contains nuclear fuel, which remains in place for several months at a time, but over that time it generates a huge amount of energy. The fuel is usually made of uranium, often in the form of small pellets of uranium dioxide, a ceramic, stacked inside hollow metal tubes or fuel rods, which can be anything from a metre to four metres in length, depending on the reactor design. Each rod is about the diameter of a pencil, and the rods are assembled into carefully designed bundles, which in turn are fixed in place securely within the reactor. There are two isotopes (or different types) of uranium, and only one of these is a material which is ‘fissionable’—that is to say, if an atom of this uranium isotope is hit by a neutron, then it can split into two smaller atoms, giving off energy in the process and also emitting more neutrons. This, and other pathways, are illustrated in Fig. 6.1 (Source: CEA). Controlling the reaction, so that the energy from the fission of uranium atoms is given out slowly over a period of years, requires two aspects of the process to be carefully balanced. 1. First, there must be enough fissile atoms in the fuel so that—on average— each fission leads to exactly one other. Any fewer, and the reaction will die away.

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