396 research outputs found

    Assessing Atmospheric Pollution and Its Impacts on the Human Health

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    This reprint contains articles published in the Special Issue entitled "Assessing Atmospheric Pollution and Its Impacts on the Human Health" in the journal Atmosphere. The research focuses on the evaluation of atmospheric pollution by statistical methods on the one hand, and on the other hand, on the evaluation of the relationship between the level of pollution and the extent of its effect on the population's health, especially on pulmonary diseases

    Advances in Binders for Construction Materials

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    The global binder production for construction materials is approximately 7.5 billion tons per year, contributing ~6% to the global anthropogenic atmospheric CO2 emissions. Reducing this carbon footprint is a key aim of the construction industry, and current research focuses on developing new innovative ways to attain more sustainable binders and concrete/mortars as a real alternative to the current global demand for Portland cement.With this aim, several potential alternative binders are currently being investigated by scientists worldwide, based on calcium aluminate cement, calcium sulfoaluminate cement, alkali-activated binders, calcined clay limestone cements, nanomaterials, or supersulfated cements. This Special Issue presents contributions that address research and practical advances in i) alternative binder manufacturing processes; ii) chemical, microstructural, and structural characterization of unhydrated binders and of hydrated systems; iii) the properties and modelling of concrete and mortars; iv) applications and durability of concrete and mortars; and v) the conservation and repair of historic concrete/mortar structures using alternative binders.We believe this Special Issue will be of high interest in the binder industry and construction community, based upon the novelty and quality of the results and the real potential application of the findings to the practice and industry

    Quantifying non-exhaust emissions and the impact of hybrid and electric vehicles using combined measurement and modelling approaches

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    Road traffic is a significant emission source of urban particulate matter (PM). Due to the implementation of exhaust regulatory standards in the UK, PM emissions which arise from the wear of brakes, tyres and the road surface, together with the resuspension of road dust are now predicted to exceed tailpipe emissions. While a growing body of academic literature has developed in recent years, non-exhaust emissions (NEE) remain unregulated and largely understudied, and the impact of powertrain electrification on the vehicle fleet has not been quantified. Thus, the aim of this thesis is to improve our understanding of these important emission sources and to determine the impact of NEE on urban air pollution - both now, and in the future. A series of highly time-resolved atmospheric measurement campaigns has been undertaken at roadside and background locations to determine roadside traffic increments. These measurements provide a comprehensive dataset of traffic emissions in London, Birmingham and Manchester, incorporating locations with different vehicle mix and speed, during summer and winter periods. PM mass and elemental tracers have been used to estimate the contribution of NEE concentrations using a scaling factor approach. A novel CO2 dilution approach has been undertaken to determine average fleet emission factors (EFs), whilst the impact of electric vehicle regenerative braking has also been simulated. The results indicate that NEE concentrations and EFs are highly dependent upon meteorological conditions, traffic speed, traffic volume and vehicle class. Brake wear is the dominant source of road traffic PM emissions in congested environments, whilst for each emission source, heavy duty vehicles (HDVs) contribute an order of magnitude greater than light duty vehicles (LDVs). On the other hand, despite the predicted increase in mass, the regenerative braking simulations suggest that passenger vehicles under electric powertrains will reduce brake wear emissions by 65 – 95%. This reduction depends on the assessed drive cycle and vehicle class, highlighting the importance of driving style on future brake wear emissions. The EFs developed in this thesis have been combined with traffic forecasts to project total national emissions in the UK up to 2035 – and can be used to validate the national atmospheric emission inventory. To conclude, a number of recommendations have been made with respect to air quality measurement strategies and emission policies which are needed to further our understanding of NEE, and to reduce these traffic-related emissions. It is proposed that a multi-disciplinary study should be undertaken encompassing laboratory dynamometer testing, on-vehicle measurements and environmental atmospheric measurements.Open Acces

    Environmental Impact Assessment by Green Processes

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    Primary energy consumption around the world has been increasing steadily since the Industrial Revolution and shows no signals of slowing down in the coming years. This trend is accompanied by the increasing pollutant concentration on the Earth’s biosystems and the general concerns over the health and environmental impacts that will ensue. Air quality, water purity, atmospheric CO2 concentration, etc., are some examples of environmental parameters that are degrading due to human activities. These ecosystems can be safeguarded without renouncing industrial development, urban and economic development through the use of low environmental impact technologies instead of equivalent pollutant ones or through the use of technologies to mitigate the negative impact of high emissions technologies. Pollutant abatement systems, carbon capture technologies, biobased products, etc. need to be established in order to make environmental parameters more and more similar to the pre-industrialization values of the planet Earth. In 15 papers international scientists addressed such topics, especially combining a high academic standard coupled with a practical focus on green processes and a quantitative approach to environmental impacts

    PhD students´day FMST 2023

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    The authors gave oral presentations of their work online as part of a Doctoral Students’ Day held on 15 June 2023, and they reflect the challenging work done by the students and their supervisors in the fields of metallurgy, materials engineering and management. There are 82 contributions in total, covering a range of areas – metallurgical technology, thermal engineering and fuels in industry, chemical metallurgy, nanotechnology, materials science and engineering, and industrial systems management. This represents a cross-section of the diverse topics investigated by doctoral students at the faculty, and it will provide a guide for Master’s graduates in these or similar disciplines who are interested in pursuing their scientific careers further, whether they are from the faculty here in Ostrava or engineering faculties elsewhere in the Czech Republic. The quality of the contributions varies: some are of average quality, but many reach a standard comparable with research articles published in established journals focusing on disciplines of materials technology. The diversity of topics, and in some cases the excellence of the contributions, with logical structure and clearly formulated conclusions, reflect the high standard of the doctoral programme at the faculty.Ostrav

    Utilizing Surgical Smoke to Improve Cancer Surgery

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    Leikkaus on yleinen ja vakiintunut kiinteiden syöpäkasvaimien hoitomuoto, jossa kasvain pyritään poistamaan siten, että sen ulkoreunaan jää kaistale tervettä kudosta eli poisto tapahtuu ns. tervekudosmarginaalilla. Mikäli marginaalia ei ole tai se ei ole riittävän leveä, kasvain uusiutuu helposti, sillä on erittäin todennäköistä, että elimistöön jää syöpäsoluja, jotka voivat muodostaa uuden kasvaimen. Kuitenkin esimerkiksi aivokasvaimia leikataan pyrkien minimoimaan tervekudoksen poisto, jottei leikkaus aiheuttaisi aivovauriota. Silmämääräisesti tämän rajan tunnistaminen on haastavaa. Verenvuodon vähentämiseksi leikkauksissa käytetään sähköveistä, joka tuottaa savukaasuja. Savukaasut ovat leikkaussalihenkilöstölle haitallisia, ja siksi ne poistetaan savuimulla. Savuimusta voidaan ottaa näytteitä, jotka sisältävät kemiallista informaatiota leikatusta kudoksesta. Niiden avulla on mahdollista optimoida poistettavan kudoksen määrää ja valvoa kasvaimen tervekudosmarginaalia. Menetelmä voi vähentää uusintaleikkauksien tarvetta merkittävästi. Väitöskirjassa tutkitaan savukaasun koostumusta ja sen mahdollisia vaikutuksia leikkausalueen lähellä työskenteleviin ihmisiin sekä kaasun ominaisuuksien käyttöä tervekudosmarginaalin valvonnassa. Tarkemmin tarkastelemme eri kudostyyppien kuormittavuuseroja henkilökunnalle. Tutkimme DMS:n käyttökelpoisuutta aivokasvaimia tunnistettaessa ex vivo. Matala- asteinen gliooma (luokka II) kyettiin tunnistamaan 94 %:n tarkkuudella verrokkiin nähden. Tutkimme eri putkimateriaalien, lämpötilojen ja mittojen vaikutusta laitteiston kemiallisen signaalin siirtonopeuteen mittausjärjestelmässä. Kemiallisen signaalin viiveet vaikuttavat huomattavasti reaaliaikaisen järjestelmän käytettävyyteen. Siksi tutkimmekin kemiallisen signaalin siirtonopeutta ja siirtonopeuden vaikutusta järjestelmän käytettävyyteen.A surgical operation is common practice when treating solid cancer tumours. The tumour is removed with a layer of healthy tissue around it to achieve a so-called negative tissue margin. Without the margin or with an incomplete margin, the cancer will likely recur, since some of the leftover cells can regrow into a new tumour. Still, in some tumours, such as brain tumours, minimizing the removal of healthy tissue takes priority over a negative margin to avoid brain damage. It is often difficult to visually recognize the border of the tumour. To decrease bleeding, these operations are performed with an electric knife. The process produces smoke that is harmful to the operating theatre personnel, and the smoke is thus recommended to be removed with a surgical smoke evacuator. During surgical removal, it is possible to distinguish benign from malignant tissue based on the smoke. This makes it possible to detect when the knife hits the tumour and to alert the surgeon, which enables the surgeon to optimize the amount of removed tissue and ensure a sufficient healthy tissue margin. This process should notably decrease the need for reoperations. In this dissertation, two topics are studied: the structure of surgical smoke as well as the type of risk that operating theatre personnel could be exposed to; and, on the other hand, the possibilities of utilizing the smoke to monitor the tumour resection margin and factors in the analysis equipment affecting its technical performance. More precisely, the studied aspects are the surgical smoke load for the theatre personnel and the classification of tissue types based on surgical smoke. We studied the utilization of differential mobility spectrometry (DMS) to diagnose brain tumours ex vivo. Low-grade glioma (class II) was classified with an accuracy of 94% when compared to control samples. Furthermore, we studied the effect of different tube materials, tube dimensions and temperature on the recovery speed of the measuring system. Delays in the chemical pathway affect the usability of the whole system. Thus, we also studied the chemical signal delays and their effects on system usability

    Aromatic Selection for Surrogate Jet Fuel

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    The aromatic component of jet fuel is limited to 25% by volume in the current aviation specification for commercial flight. Aromatic hydrocrabons present in petroleum fuels are acknowledged to contribute to the formation of polycyclic aromatic hydrocarbons (PAH) and subsequently high levels of soot. Non-volatile particulate matter in the form of soot, or black carbon, contributes significantly to global warming, contrail formation, the degradation of combustion liner walls and has an adverse effect on human health. There is significant interest in minimising the emission levels of non-volatile particulate matter and smoke by varying the source and chemical composition of Jet fuel. While the overall volumetric proportion of aromatics is currently regulated, there is no indication as to the effect of the molecular composition of the aromatic component. The composition of conventional and surrogate fuels with specific focus on the variation of aromatic type and composition is investigated in this work with the goal of reducing the emission of nVPM in the aviation sector. In this report, a metadata analysis of the correlation between aromatic and naphthalene content and the smoke point of fuel samples finds a week correlation between the two variables as determined by the Jet fuel specification. The composition of Jet fuel is then discussed as is the contemporary understanding of the various formation mechanisms of non-volatile particulate matter. A literature review of the effect of molecular composition of the aromatic component on soot formation found a correlation with total aromatic volume, naphthalene volume, hydrogen mass proportion and the proportion of ring carbon present, although no individual factor agreed consistently with experimental results. A knowledge gap was identified as to 0 the effect of varying individual aromatic species in an aviation context. This report presents experimental data collected using a Rolls Royce Tay single can combustor using extractive laser induced incandescence to measure the mass concentration of black carbon emitted by thirteen different aromatic species in four blend proportions (7.5%, 12.5%, 17.5%, 22.5% vol/vol) in an alkene paraffinic surrogate for Jet-A. Data for the same configuration is also presented using a differential mobility analyser to determine the size distribution and total number concentration when combusting sixteen aromatics in three blend proportions (8%, 13%, 18% vol/vol). Fuel global density and the aggregate Unified YSI were found to be of statistical significance and regression models were developed to estimate black carbon mass and number exhaust concentrations with high accuracy

    Experimental and Computational Investigations on the Adsorption Applications of Covalent Triazine Frameworks

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    As an emerging subclass of advanced nanoporous materials, covalent triazine frameworks (CTFs) possess distinct properties such as high specific surface area, large pore volume, exceptional thermal/chemical stability, and structural designability. Thus, they have many real-world applications, including, but not limited to, catalysis, energy storage and conversion, adsorption, chemical sensing, and separation. In this doctoral dissertation, three projects related to CTF materials have been performed. Firstly, two electron-rich π-conjugated CTFs with high specific surface area and pore volume were synthesized via the facile and convenient Friedel-Crafts alkylation reaction of cyanuric chloride and trans-stilbene (TS) as well as diphenylacetylene (DPA), containing conjugated C=C double bond and C≡C triple bond functionalities, respectively. The iodine-capturing performance of these two electron-rich CTFs was investigated in a combined experimental-computational approach. Secondly, to design novel functionalized CTFs suitable for heavy metal cations removal from aqueous solutions, a DFT-assisted computational screening approach was employed on various CTFs featuring different electron-rich functionalities with negatively charged atom(s) for efficient adsorption of Cd2+, Pb2+, and Hg2+ cations as three most biohazardous heavy metal species. The metal removal process was also investigated in a combined experimental-computational approach. Thirdly, the gas adsorption and sensing properties of the pristine CTF-1 covalent triazine framework and its platinum atom (Pt)-doped counterpart were investigated computationally for SF6 decomposition products (i.e., H2S, SO2, SOF2, and SO2F2 gases) using the density-functional theory (DFT) method. In this framework, density of states (DOS) analysis examined the adsorption and sensing mechanisms. Computational and experimental results obtained in this dissertation confirmed the promising performance of the CTF materials in efficiently eliminating environmental micropollutants via adsorption

    Natural or anthropogenic variability? A long-term pattern of the zooplankton communities in an ever-changing transitional ecosystem

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    The Venice Lagoon is an important site belonging to the Italian Long-Term Ecological Research Network (LTER). Alongside with the increasing trend of water temperature and the relevant morphological changes, in recent years, the resident zooplankton populations have also continued to cope with the colonization by alien species, particularly the strong competitor Mnemiopsis leidyi. In this work, we compared the dynamics of the lagoon zooplankton over a period of 20 years. The physical and biological signals are analyzed and compared to evaluate the hypothesis that a slow shift in the environmental balance of the site, such as temperature increase, sea level rise (hereafter called “marinization”), and competition between species, is contributing to trigger a drift in the internal equilibrium of the resident core zooplankton. Though the copepod community does not seem to have changed its state, some important modifications of structure and assembly mechanisms have already been observed. The extension of the marine influence within the lagoon has compressed the spatial gradients of the habitat and created a greater segregation of the niches available to some typically estuarine taxa and broadened and strengthened the interactions between marine species
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