Letteratura scientifica selezionata sul tema "Particules volatiles"
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Articoli di riviste sul tema "Particules volatiles":
1
Lukić, Igor, Nina Išić, Dean Ban, Branka Salopek Sondi e Smiljana Goreta Ban. "Comprehensive Volatilome Signature of Various Brassicaceae Species". Plants 12, n. 1 (1 gennaio 2023): 177. http://dx.doi.org/10.3390/plants12010177.
Abstract (sommario):
To investigate in detail the volatilomes of various Brassicaceae species, landraces, and accessions, and to extract specific volatile markers, volatile aroma compounds were isolated from plant samples by headspace solid-phase microextraction and analyzed by gas chromatography/mass spectrometry (HS-SPME-GC/MS). The data obtained were subjected to uni- and multivariate statistical analysis. In general, two cabbage (Brassica oleracea L. var. capitata) landraces emitted the lowest amounts of volatiles generated in the lipoxygenase (LOX) pathway. Wild species Brassica incana Ten. and Brassica mollis Vis. were characterized by relatively high trans-2-hexenal/cis-3-hexen-1-ol ratio in relation to other investigated samples. A Savoy cabbage (Brassica oleracea L. var. sabauda) cultivar and three kale (Brassica oleracea L. var. acephala) accessions exhibited particular similarities in the composition of LOX volatiles, while the LOX volatilome fraction of B. incana and B. mollis partially coincided with that of another wild species, Diplotaxis tenuifolia L. Regarding volatiles formed in the glucosinolate (GSL) pathway, Savoy cabbage and wild species B. incana, B. mollis, and D. tenuifolia showed more intense emission of isothiocyanates than cabbage and kale. Diplotaxis tenuifolia showed a rather limited production of nitriles. The results of this study contribute to the general knowledge about volatile composition from various Brassicaceae species, which could be exploited for their better valorization. Future studies should focus on the influence of various environmental, cultivation, and post-harvest factors to obtain data with a higher level of applicability in practice.
2
Gualtieri, Liberata, Maurilia Maria Monti, Francesca Mele, Assunta Russo, Paolo Alfonso Pedata e Michelina Ruocco. "Volatile Organic Compound (VOC) Profiles of Different Trichoderma Species and Their Potential Application". Journal of Fungi 8, n. 10 (21 settembre 2022): 989. http://dx.doi.org/10.3390/jof8100989.
Abstract (sommario):
Fungi emit a broad spectrum of volatile organic compounds (VOCs), sometimes producing species-specific volatile profiles. Volatilomes have received over the last decade increasing attention in ecological, environmental and agricultural studies due to their potential to be used in the biocontrol of plant pathogens and pests and as plant growth-promoting factors. In the present study, we characterised and compared the volatilomes from four different Trichoderma species: T. asperellum B6; T. atroviride P1; T. afroharzianum T22; and T. longibrachiatum MK1. VOCs were collected from each strain grown both on PDA and in soil and analysed using proton transfer reaction quadrupole interface time-of-flight mass spectrometry (PTR-Qi-TOF-MS). Analysis of the detected volatiles highlighted a clear separation of the volatilomes of all the four species grown on PDA whereas the volatilomes of the soil-grown fungi could be only partially separated. Moreover, a limited number of species-specific peaks were found and putatively identified. In particular, each of the four Trichoderma species over-emitted somevolatiles involved in resistance induction, promotion of plant seed germination and seedling development and antimicrobial activity, as 2-pentyl-furan, 6PP, acetophenone and p-cymene by T. asperellum B6, T. atroviride P1, T. afroharzianum T22 and T. longibrachiatum MK1, respectively. Their potential role in interspecific interactions from the perspective of biological control is briefly discussed.
3
Bangerth, Fritz K., Jun Song e Josef Streif. "Physiological Impacts of Fruit Ripening and Storage Conditions on Aroma Volatile Formation in Apple and Strawberry Fruit: A Review". HortScience 47, n. 1 (gennaio 2012): 4–10. http://dx.doi.org/10.21273/hortsci.47.1.4.
Abstract (sommario):
After a brief description of the “history of research” of aroma volatiles of apple and strawberry fruit, possible reasons for the reduced production of these important quality attributes by particular pre- and postharvest procedures are given. Among the possible physiological factors in association with reduced aroma volatile production, a reduced ethylene sensitivity, a decline in the rate of respiration as well as the content of adenine nucleotides and limited free fatty acids as precursors for aroma volatiles biosynthesis are proposed. A hypothesis about how this sequence of events leads to reduced volatile production is given and finally some suggestions of how to improve volatile synthesis are discussed.
4
Archbold, Douglas D., Ann M. Clements, T. R. Hamilton-Kemp e R. W. Collins. "391 Compression Bruising Alters the Strawberry Volatile Profile". HortScience 34, n. 3 (giugno 1999): 511C—511. http://dx.doi.org/10.21273/hortsci.34.3.511c.
Abstract (sommario):
Prior work indicated that volatile compounds produced by macerated strawberry fruit occurred at levels capable of affecting pathogen development. To determine if a less-severe injury, such as bruising, would alter the volatile profile of strawberry fruit, the headspace volatiles from ripe `Tribute' strawberry fruit were sampled with SPME fiber during the 15 min immediately following and from 75 to 90 min following application of a compression bruise. The compression bruise was applied with a force gauge, and fruit were kept in a closed bottle at room temperature during the study. Of the 14 major volatile products consistently produced by all fruit, acetate esters derived from hexanal, (E)-2-hexenal, and (Z)-3-hexenal increased most, over 50%, in response to bruising during the first interval. During the later interval, bruised fruit produced over 50% more (E)-2-hexenyl acetate and hexyl acetate than control fruit. Most notably, the ratio of levels of (E)-2-hexenyl acetate produced by bruised compared to control fruit were the highest among all 14 major volatiles, over 150% more after 15 min and 270% more at 90 min. Headspace levels of the 6-carbon acetate esters declined for both control and bruised fruit between 15 and 90 min, while levels of the other major volatiles increased. The other 11 volatile compounds were commonly identified aroma volatiles. Headspace levels of some of these were also higher from bruised than control fruit. In particular, headspace levels of ethyl butyrate were increased by bruising 13% after 15 min but over 100% after 90 min, the most of any volatile product other than (E)-2-hexenyl acetate.
5
Mülner, Pascal, Elisa Schwarz, Kristin Dietel, Stefanie Herfort, Jennifer Jähne, Peter Lasch, Tomislav Cernava, Gabriele Berg e Joachim Vater. "Fusaricidins, Polymyxins and Volatiles Produced by Paenibacillus polymyxa Strains DSM 32871 and M1". Pathogens 10, n. 11 (15 novembre 2021): 1485. http://dx.doi.org/10.3390/pathogens10111485.
Abstract (sommario):
Paenibacilli are efficient producers of potent agents against bacterial and fungal pathogens, which are of great interest both for therapeutic applications in medicine as well as in agrobiotechnology. Lipopeptides produced by such organisms play a major role in their potential to inactivate pathogens. In this work we investigated two lipopeptide complexes, the fusaricidins and the polymyxins, produced by Paenibacillus polymyxa strains DSM 32871 and M1 by MALDI-TOF mass spectrometry. The fusaricidins show potent antifungal activities and are distinguished by an unusual variability. For strain DSM 32871 we identified numerous yet unknown variants mass spectrometrically. DSM 32871 produces polymyxins of type E (colistins), while M1 forms polymyxins P. For both strains, novel but not yet completely characterized polymyxin species were detected, which possibly are glycosylated. These compounds may be of interest therapeutically, because polymyxins have gained increasing attention as last-resort antibiotics against multiresistant pathogenic Gram-negative bacteria. In addition, the volatilomes of DSM 32781 and M1 were investigated with a GC–MS approach using different cultivation media. Production of volatile organic compounds (VOCs) was strain and medium dependent. In particular, strain M1 manifested as an efficient VOC-producer that exhibited formation of 25 volatiles in total. A characteristic feature of Paenibacilli is the formation of volatile pyrazine derivatives.
6
Cozzolino, Rosaria, Matteo Stocchero, Rosa Perestrelo e José S. Câmara. "Comprehensive Evaluation of the Volatomic Fingerprint of Saffron from Campania towards Its Authenticity and Quality". Foods 11, n. 3 (27 gennaio 2022): 366. http://dx.doi.org/10.3390/foods11030366.
Abstract (sommario):
The volatile profiles of eight saffron samples (seven cultivated and one spontaneous) grown in different geographical districts within the Campania region (southern Italy) were compared. Using headspace solid-phase microextraction coupled to gas chromatography–mass spectrometry (HS-SPME/GC-MS), overall, 80 volatiles were identified in the eight landraces. Among them, safranal and its isomers and other related compounds such as isophorones, which are not only key odorants but also pharmacologically active metabolites, have been detected in all the investigated samples. Principal Component Analysis performed on the volatiles’ compounds revealed that the spontaneous sample turned out to be an outlier. In particular, the volatile organic compounds (VOCs) profile of the spontaneous saffron presented four lilac aldehydes and four lilac alcohol isomers, which, to the authors’ knowledge, have never been identified in the volatile signature of this spice. The multivariate statistical analysis allowed the discrimination of the seven cultivate saffron ecotypes in four well-separated clusters according to variety. Moreover, 20 VOCs, able to differentiate the clusters in terms of single volatile metabolite, were discovered. Altogether, these results could contribute to identifying possible volatile signature metabolites (biomarkers) or patterns that discriminate saffron samples grown in Campania region on a molecular basis, encouraging future biodiversity programs to preserve saffron landraces revealing valuable genetic resources.
7
González-Domínguez, Raúl, Ana Sayago, Ikram Akhatou e Ángeles Fernández-Recamales. "Volatile Profiling of Strawberry Fruits Cultivated in a Soilless System to Investigate Cultivar-Dependent Chemical Descriptors". Foods 9, n. 6 (11 giugno 2020): 768. http://dx.doi.org/10.3390/foods9060768.
Abstract (sommario):
Volatile compounds are essential for food organoleptic characteristics and of great utility for the food industry as potential markers for authenticity purposes (e.g., variety, geographical origin, adulteration). The aim of this study was to determine the characteristic volatile compounds of strawberry samples grown in a soilless system by using headspace solid phase micro-extraction coupled with gas chromatography and to investigate the influence of cultivar (Festival, Candonga, Camarosa) on this volatile profile. We observed that Festival and, to a lesser extent, Candonga varieties were characterized by the richest aroma-related profiles, including higher levels of esters, furanones and terpenes. In particular, methyl butyrate, hexyl hexanoate, linalool, geraniol and furaneol were the most abundant aromatic compounds detected in the three varieties of strawberries. Complementarily, the application of pattern recognition chemometric approaches, including principal component analysis and linear discriminant analysis, demonstrated that concentrations of specific volatiles can be employed as chemical descriptors to discriminate between strawberry cultivars. Accordingly, geraniol and hexyl hexanoate were found to be the most significant volatiles for the discrimination of strawberry varieties.
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Piette, Anjali A. A., Peter Gao, Kara Brugman, Anat Shahar, Tim Lichtenberg, Francesca Miozzi e Peter Driscoll. "Rocky Planet or Water World? Observability of Low-density Lava World Atmospheres". Astrophysical Journal 954, n. 1 (21 agosto 2023): 29. http://dx.doi.org/10.3847/1538-4357/acdef2.
Abstract (sommario):
Abstract Super-Earths span a wide range of bulk densities, indicating a diversity in interior conditions beyond that seen in the solar system. In particular, an emerging population of low-density super-Earths may be explained by volatile-rich interiors. Among these, low-density lava worlds have dayside temperatures that are high enough to evaporate their surfaces, providing a unique opportunity to probe their interior compositions and test for the presence of volatiles. In this work, we investigate the atmospheric observability of low-density lava worlds. We use a radiative-convective model to explore the atmospheric structures and emission spectra of these planets, focusing on three case studies with high observability metrics and substellar temperatures spanning ∼1900–2800 K: HD 86226 c, HD 3167 b, and 55 Cnc e. Given the possibility of mixed volatile and silicate interior compositions for these planets, we consider a range of mixed volatile and rock-vapor atmospheric compositions. This includes a range of volatile fractions and three volatile compositions: water-rich (100% H2O), water with CO2 (80% H2O+20% CO2), and a desiccated O-rich scenario (67% O2+33% CO2). We find that spectral features due to H2O, CO2, SiO, and SiO2 are present in the infrared emission spectra as either emission or absorption features, depending on dayside temperature, volatile fraction, and volatile composition. We further simulate JWST secondary-eclipse observations for each of the three case studies, finding that H2O and/or CO2 could be detected with as few as ∼five eclipses. Detecting volatiles in these atmospheres would provide crucial independent evidence that volatile-rich interiors exist among the super-Earth population.
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Hussain, Hidayat, Ahmed Al-Harrasi, Ahmed Al-Rawahi e Javid Hussain. "Chemistry and Biology of Essential Oils of GenusBoswellia". Evidence-Based Complementary and Alternative Medicine 2013 (2013): 1–12. http://dx.doi.org/10.1155/2013/140509.
Abstract (sommario):
The properties ofBoswelliaplants have been exploited for millennia in the traditional medicines of Africa, China, and especially in the Indian Ayurveda. In Western countries, the advent of synthetic drugs has obscured the pharmaceutical use ofBoswellia, until it was reported that an ethanolic extract exerts anti-inflammatory and antiarthritic effects. Frankincense was commonly used for medicinal purposes. This paper aims to provide an overview of current knowledge of the volatile constituents of frankincense, with explicit consideration concerning the diverseBoswelliaspecies. Altogether, more than 340 volatiles inBoswelliahave been reported in the literature. In particular, a broad diversity has been found in the qualitative and quantitative composition of the volatiles with respect to different varieties ofBoswellia. A detailed discussion of the various biological activities ofBoswelliafrankincense is also presented.
10
Cozzolino, Rosaria, Bernardo Pace, Michela Palumbo, Carmine Laurino, Gianluca Picariello, Francesco Siano, Beatrice De Giulio, Sergio Pelosi e Maria Cefola. "Profiles of Volatile and Phenolic Compounds as Markers of Ripening Stage in Candonga Strawberries". Foods 10, n. 12 (14 dicembre 2021): 3102. http://dx.doi.org/10.3390/foods10123102.
Abstract (sommario):
Volatile compounds, quality traits (total phenols and antioxidant capacity) and High-performance liquid chromatography (HPLC)-isolated polyphenols of strawberries, variety Sabrosa, commercially referred to as “Candonga”, harvested at three different times (H1, H2 and H3) and at two different ripening stages, namely half-red (Half-red-H1, Half-red-H2 and Half-red-H3) and red (Red-H1, Red-H2 and Red-H3) were evaluated. Dominant anthocyanins, namely cyanidin-3-O-glucoside, pelargonidin-3-O-glucoside and pelargonidin-3-O-rutinoside, as well as p-coumaryl hexoside increased during harvesting, differently from flavonoids, such as quercetin-3-O-glucoside, kaempferol-3-O-glucoronide and quercetin 3-O-glucoronide, that declined. Samples clustered in different quadrants of the principal component analysis (PCA) performed on volatiles, quality traits and phenolic compounds, highlighting that only the red samples were directly correlated to volatile components, as volatiles clearly increased both in number and amount during ripening. In particular, volatiles with a positive impact on the consumers’ acceptance, including butyl butyrate, ethyl hexanoate, hexyl acetate, nonanal, terpenes and lactones, were positively associated with the Red-H1 and Red-H2 strawberries, while volatiles with negative coefficients related to consumer liking, including isopropyl butyrate, isoamyl butyrate and mesifurane directly correlated with the Red-H3 samples. Accordingly, strawberries harvested at Red-H1 and Red-H2 ripening stages could be preferred by the consumers compared to the Red-H3 fruit. Altogether, these results could help to individuate quality traits as putative markers of the ripening stage, and optimize the process of post-harvesting ripening to preserve or improve the desirable aromatic characteristics of strawberries.
Tesi sul tema "Particules volatiles":
1
Barrellon-Vernay, Rafaël. "Mécanismes de nucléation des particules volatiles dans les émissions des moteurs d'avions et leurs liens avec la composition du carburant". Electronic Thesis or Diss., Université de Lille (2022-....), 2023. https://pepite-depot.univ-lille.fr/ToutIDP/EDSMRE/2023/2023ULILR059.pdf.
Abstract (sommario):
L'une des préoccupations actuelles de l'industrie aéronautique est la diminution de la consommation de carburant et de l'empreinte environnementale. En effet, les émissions aéronautiques ont un impact sur la qualité de l'air et notamment au niveau des zones aéroportuaires. Comme d'autres secteurs du transport, le trafic aérien génère des gaz à effet de serre (2 % du total dans le monde), des traînées de condensation ainsi que des particules volatiles et non volatiles (vPM et nvPM).Pour réduire ces émissions, différentes approches ont été pensées avec en particulier l'usage de carburants aéronautiques durables (SAF - Sustainable Aviation Fuels). L'objectif des SAF est de réduire les émissions nettes de CO2 et de nvPM. Cependant, la combustion de ces carburants peut entraîner la formation de nouveaux polluants qui réagissent avec l'atmosphère en formant des aérosols secondaires (SA). Dans le cadre du projet UNREAL (Unveiling Nucleation mechanism in aiRcraft Engine exhAust and its Link with fuel composition), l'objectif de ce travail était d'étudier les différents mécanismes au niveau moléculaire à l'origine de la formation de nouvelles particules à partir des rejets moteurs alimentés par des carburants de compositions différentes, allant du Jet A-1 standard à du carburant 100 % SAF.La caractérisation physico-chimique des émissions en conditions réelles en sortie moteur est un défi à la fois d'un point de vue technique et économique. Pour pallier à cela un brûleur mini-CAST, adapté à la combustion de carburants liquides aéronautiques, a été utilisé comme alternative pour obtenir des émissions comparables, dans une certaine mesure, à celles des moteurs aéronautiques. Une diminution des émissions de nvPM (concentration en nombre, concentration en masse et distribution de tailles) peut être observée en corrélation avec la quantité de composés aromatiques présents dans le carburant. De plus, l'analyse par spectrométrie de masse a révélé une diminution de l'intensité relative des HAP lors de l'emploi de carburants alternatifs. Les émissions du brûleur ont été injectées, avec ou sans filtration des suies, dans une chambre atmosphérique de vieillissement (chambre CESAM reproduisant les conditions atmosphériques au niveau du sol - LISA). Pour tous les carburants testés, la formation de vPM par nucléation homogène a été observée dans la chambre atmosphérique en l'absence de nvPM. Ce phénomène est particulièrement prononcé pour les carburants comprenant de grandes quantités de soufre dans leur composition. Cependant, dans les cas réels (présence de suies), la formation de vPM n'est observée que pour les carburants contenant de fortes quantités de soufre. La concentration de précurseurs gazeux formés pour les autres carburants n'est pas suffisante pour produire des vPM, notamment avec l'adsorption des gaz à la surface des particules de suies (nucléation hétérogène). Les techniques de caractérisation en ligne ont été complétées par des prélèvements sur filtre et une analyse par spectrométrie de masse, mettant en évidence la présence de HAP, d'hydrocarbures oxygénés, de composés soufrés et azotés. En utilisant des méthodes semi-quantitatives, il a été possible de mettre en relation la composition chimique (intensité relative de soufre et de HAP) avec la formation de vPM et leur répartition dans les phases particulaires et gazeuses des émissionsOne of the actual concerns of the aviation industry is to reduce fuel consumption and environmental footprint. Indeed, aviation emissions impact air quality in and around airports. As other transport sectors, aviation effluents need to be addressed to reduce greenhouse gases contribution (2% of these emissions are related to air transport worldwide), volatile and non-volatile Particulate Matter (vPM and nvPM) and indirect impact as condensation trails.To reduce these emissions, different approaches have been investigated, in particular the use of Sustainable Aviation Fuels (SAF). Aims of SAF are to decrease the net CO2 emissions and nvPM. However, combustion of these fuels may lead to new pollutants that can react with atmosphere by formation of secondary aerosols. As part of the UNREAL project (Unveiling Nucleation mechanism in aiRcraft Engine exhAust and its Link with fuel composition), the objective of this work was to study the different molecular mechanisms of new particle formation from the exhausts of aircraft engines fed by fuels with different composition, from the standard Jet A-1 to 100 % SAF fuel.The physicochemical characterisation of the particulate emissions from aircraft engines in real conditions is challenging both from the technical and economical point of view. Thus, a mini-CAST burner, suitable for the combustion of aeronautic liquid fuels, has been used as an alternative to obtain emissions comparable to some extent to those from aircraft engines. A decrease in nvPM emissions (number concentration, mass concentration and size distribution) can be observed in correlation with the quantity of aromatic compounds in the fuel. Moreover, the analysis by mass spectrometry revealed a decrease in the relative intensity of PAHs when alternative fuels were employed . Emissions from the burner have been injected, with and without soot filtration, into an atmospheric chamber for ageing (CESAM chamber reproducing atmospheric conditions at ground level - LISA). For all fuels tested formation of vPM by homogeneous nucleation has been observed in the atmospheric chamber in absence of nvPM. This phenomenon is particularly highlighted for fuels with high amounts of sulphur in their compositions. However, in real cases (presence of soot), the formation of vPM is only observed for the fuels containing high amounts of sulphur. The concentration of gaseous precursors formed for other fuels was not enough to produce vPM after being adsorbed on soot surface (heterogeneous nucleation). On-line characterisation techniques were completed by filter sampling and off-line mass spectrometry analysis, highlighting the presence of PAHs, oxygenated hydrocarbons, sulphur and nitrogen compounds. By employing semi-quantitative methods, it was possible to link the relative chemical composition (sulphur and PAH relative intensity) with vPM formation and their repartitions in particulate and gaseous phases
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Pflieger, Maryline. "Etude de la dégradation photochimique des pesticides adsorbés à la surface de particules atmosphériques". Phd thesis, Université de Provence - Aix-Marseille I, 2009. http://tel.archives-ouvertes.fr/tel-00414758.
Abstract (sommario):
Une fraction significative de pesticides intègre le compartiment atmosphérique notamment durant les épandages agricoles. L'atmosphère est ainsi considérée comme un important vecteur de dissémination de ces composés dans l'environnement. Par conséquent, une bonne connaissance de leur comportement atmosphérique est indispensable à la compréhension de leur devenir environnemental. Actuellement, il existe une incohérence entre les brèves durées de vie atmosphérique estimées (à partir de la réactivité théorique en phase gazeuse) et les observations de terrain (prenant en compte les phases gazeuse et particulaire) qui révèlent souvent des transports sur de longues distances. L'objectif de ce travail a été d'aborder cette problématique par l'étude de la réactivité de trois pesticides (alachlore, trifluraline et terbuthylazine) adsorbés à la surface de particules de silice au sein d'un réacteur à écoulement et sous conditions simulées. Des protocoles expérimentaux ont été spécialement développés pour observer les cinétiques supposées lentes de ces herbicides vis-à-vis de l'ozone et des radicaux hydroxyles. Les résultats obtenus tendent à corroborer l'hypothèse suggérant que les temps de vie atmosphérique des pesticides actuellement utilisés sont sous-estimés, du moins pour les composés les moins volatils. Il paraît donc nécessaire de poursuivre les investigations sur la réactivité hétérogène des pesticides pour pouvoir obtenir une image plus complète de leur comportement vis-à-vis de la dégradation atmosphérique, ce qui permettrait à terme de déterminer des durées de vie atmosphériques plus réalistes.
3
Manoukian, Audrey. "Développement d'un dispositif expérimental pour la mesure des émissions induites par la combustion des parfums d'ambiance". Thesis, Aix-Marseille, 2012. http://www.theses.fr/2012AIXM4823/document.
Abstract (sommario):
La composition de l'air intérieur est complexe et fortement influencée par les activités humaines. Celles-ci engendrent notamment l'émission de composés organiques et de particules. Les inquiétudes grandissantes quant à la qualité de l'air intérieur et à son impact sanitaire ont contraint les pouvoirs publics à prendre des mesures pour mieux assurer son suivi. Parmi les activités humaines fréquemment soupçonnées de contribuer à la contamination de l'air intérieur, on retrouve l'utilisation de parfums d'ambiance de types encens et bougies. De récentes études ont montré que cette pratique pouvait entraîner l'émission de composés organiques volatils (COV) et de particules. Une des carences liées à ces études résulte dans le fait qu'il n'existe pas de protocole de prélèvement et de mesures normalisés pour ce type de pratique, rendant l'exploitation et l'inter comparaison des résultats sujette à beaucoup de controverses. Les industriels français ont dès lors souhaité réagir, par la mise en place d'une méthodologie commune de mesure des émissions induites par la combustion des parfums d'ambiance. Le but de ce travail est de développer et de valider un dispositif expérimental permettant de mieux contrôler la combustion et les paramètres environnementaux qui l'influencent, afin de disposer d'un protocole expérimental calibré et reproductible. Ainsi, après avoir étudié les types de polluants et les possibilités de prélèvements et d'analyses associées, l'étude a été conduite en trois étapes. La première a été réalisée dans une pièce laboratoire simulant en taille réelle la pièce d'un logement. Elle a permis de déterminer le type de composés émis (COV et particules) par la combustion de parfums d'ambiance et les niveaux de concentrations associés. La seconde étape consistait en la réalisation d'un plan d'expériences complet dans une enceinte d'essais d'émissions pour déterminer l'influence de la température, de l'humidité relative et du taux de renouvellement d'air sur les niveaux émissions. Enfin, dans le cadre de la dernière étape, la méthode et les connaissances acquises précédemment ont été transférées à une enceinte d'essai climatique de faible volume, afin de permettre la réalisation d'analyse en routineThe indoor air composition is complex and widely influenced by human activities. These practices generate organic compound and particles. Growing concerns about indoor air quality and its impact on health have forced the government to make more studies. Among the human practices, recent studies shown that incense and candle combustion could result in the emission of volatile organic compounds (VOC) and particles. However, there is no standard sample protocol for measuring these emissions. The results comparison is then largely controversy. French manufacturers want to develop a methodology for emissions controlling due to the combustion of incense and candle processes. Through this experimental system, they want to learn much more about these processes and emissions control to anticipate the new law. Thus, after studying about the types of pollutants and sampling/analysis protocol associated, three types of studies were conducted. The first study was carried in a room of a house, to determine which kind of compounds were emitted (VOCs and particulate matter) and their concentration levels. The second study was to apply a full factorial design in a chamber emission test, to determine temperature, relative humidity and air exchange rates emissions influences. Finally, in a last study, the method and the knowledge acquired previously were transferred to a climate test chamber of small volume, allowing manufacturers to make routine analysis
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Chen, Longwen. "Etude Expérimentale de la décharge couronne pour le traitement de l'air intérieur : COV et particules". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAA022/document.
Abstract (sommario):
La qualité de l'air intérieur est devenue une préoccupation de santé publique du fait notamment de l'augmentation du temps passé dans les environnements intérieurs et les espaces clos. L'objectif de ce travail est de développer des procédés mettant en œuvre la décharge couronne afin de traiter les polluants gazeux chimiques et particulaires dans l'air intérieur. Le premier volet du travail concerne la dégradation des polluants gazeux chimiques présents en très faibles concentrations dans l’air intérieur. Le couplage d’une décharge couronne et d’un catalyseur est mis en œuvre pour dégrader du toluène dans des conditions représentatives de l’air intérieur. Cette étude démontre la très bonne efficacité de la décharge couronne vis-à-vis du toluène avec de faibles densités d’énergie. Elle identifie les conditions opératoires optimales et propose des mécanismes réactionnels suite à l’identification des principaux produits de réaction. Cependant, le plasma génère des espèces indésirables comme l'ozone et les oxydes d'azote qui doivent impérativement être détruits. Nous avons choisi d'adjoindre à la décharge couronne un catalyseur à base d'oxydes de métaux de transition (MnOx/Al2O3). Différents catalyseurs sont synthétisés puis modifiés par greffage d’agents modifiants. Leur efficacité vis-à-vis de l’ozone et des NOx est quantifiée en présence de différentes teneurs en vapeur d’eau. Le deuxième volet concerne la collecte des particules par filtration électrostatique. Trois procédés sont étudiés ; ils associent un étage d’ionisation et un étage de collecte. L’ionisation est assurée soit par un électrofiltre fil-plaque soit par des aiguilles portées à un potentiel de quelques kilovolts. L’efficacité de collecte est mesurée dans la gamme de 10 nm à 20 µm en fonction de différents paramètres opératoires (tension, polarité, vitesse, paramètres géométriques, concentration en particules, humidité, etc.). Les aiguilles ont une efficacité légèrement inférieure à celle de l’électrofiltre mais présentent une très faible production de l'ozone et une consommation énergétique moindre. L’étude paramétrique permet de dimensionner, d'optimiser la géométrie du procédé et de définir les meilleures conditions de fonctionnementIndoor air quality has become a public health issue because of the increased time spent in indoor environments and confined spaces. The goal of this work is to develop processes using corona discharge to treat chemical gaseous and particulate pollutants in indoor air. The first part of the work concerns the degradation of chemical gaseous pollutants present in very low concentrations in indoor air. The coupling of a corona discharge and a catalyst is implemented to degrade toluene under conditions representative of the indoor air. Tests were carried out under a range of operating and environmental conditions. This study demonstrates the very good efficiency of the corona discharge for toluene with very low specific density. Optimal operating conditions are identified and reaction mechanisms are proposed following the identification of the main reaction products. However, the generations of by-products, ozone and NOx, which can be hazardous compounds, have to be taken into account. The combination of corona discharge with catalysis seems as a promising way to ensure the suitability and the safety of non-thermal plasma as an indoor air cleaner. Different catalysts based on transition metal oxides (MnOx/Al2O3) are synthesized and then modified by grafting modifying agents. Their efficiency for ozone and NOx elimination is quantified in the presence of different water vapor contents. The second part concerns the particle collection by electrostatic precipitation. Three processes are studied; they combine an ionization stage and a collection stage. The ionization is ensured either by a wire-plate electrostatic precipitator (ESP) or by needles brought to a potential of a few kilovolts. The collection efficiency is measured in the range of 10 nm to 20 μm according to different operating parameters (voltage, polarity, velocity, geometrical parameters, particle concentration, humidity, etc.). The needles have a slightly lower efficiency than the ESP but present a very low production of ozone and a lower energy consumption. The parametric study makes it possible to dimension, to optimize the geometry of the process and to define the best operating conditions
5
Just, Guillaume. "Caractérisation et modélisation des mémoires Flash embarquées destinées aux applications faible consommation et à forte contrainte de fiabilité". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4716/document.
Abstract (sommario):
De nombreuses applications industrielles spécifiques dans les secteurs tels que l'automobile, le médical et le spatial, requièrent un très haut niveau de fiabilité. Ce type d'applications fonctionnant sous des contraintes sévères (haute température, corrosion, vibration, radiations,…) impose aux industriels des spécifications particulières en termes de fiabilité et de consommation d'énergie. Dans ce contexte, les travaux menés ont pour objectif d'étudier la fiabilité des mémoires Flash embarquées pour des applications faible consommation et à forte contrainte de fiabilité. Après une introduction orientée sur les deux volets d'étude que sont la caractérisation électrique et le test de mémoires non volatiles, un modèle physique capable de modéliser le courant de SILC a été développé. Cet outil permet de répondre à la problématique de perturbations en lecture (read disturb) et donne aux designers et technologues un moyen d'estimer le taux de défaillance de cellules mémoires en fonction de paramètres physiques, géométriques et électriques ainsi que des moyens d'action afin de minimiser ce phénomène indésirable. La fiabilité (oxyde tunnel, endurance) et les performances (consommation énergétique) de la cellule Flash sont ensuite étudiées en explorant les variations de paramètres du procédé de fabrication et des conditions électriques de fonctionnement. Enfin, une étude originale menée en temps réel sur plus de 15 mois est consacrée à la fiabilité en rétention des mémoires Flash soumises aux effets des particules radiatives présentes dans l'environnement naturel terrestreMany specific applications used in automotive, medical and spatial activity domains, require a very high level of reliability. These kinds of applications, working under severe constraints (high temperature, corrosion, vibration, radiations…) challenge memory manufacturers and impose them particular specifications in terms of reliability and energy consumption. In this context, work presented in this thesis aim at studying embedded Flash memories reliability for low power and high reliability applications. After an introduction oriented on areas of electrical characterizations and Test of non-volatile memories, a physical model of SILC leakage current is developed. This tool is used to answer to disturbs problematic and gives to designers and technologists a way to estimate the failure rate of memory cells according to physical, geometrical and electrical parameters, giving leads to minimize this unwanted phenomenon. Reliability (tunnel oxide, cell endurance) and performances (energy consumption) of Flash memory cell are then studied exploring process parameters variations and electrical conditions optimizations. Finally, an original real-time experiment over more than 15 months is focused on Flash memories retention reliability due to irradiative particles effects of natural terrestrial environment
6
Smith, Kilian Eric Christopher. "The transfer of semi-volatile organic chemicals into pasture". Thesis, Lancaster University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274248.
7
Rochereau, Agnès. "Traitement combiné particules / composés organiques volatils sur médias fibreux à base de carbone activé". Nantes, 2007. http://www.theses.fr/2007NANT2115.
Abstract (sommario):
En vue d'obtenir un système de traitement performant pour l'élimination simultanée de particules de diamètre aérodynamique inférieur à 10 µm (PM10) et de composés organiques volatils (COV), des médias prototypes composés de fibres de carbone activé (FCA) associées à des fibres non-adsorbantes, telles que des fibres cellulosiques (FC) et de polyester (PET), ont été réalisés par voie papetière. L'influence de différents paramètres de fabrication sur les propriétés d'usages des médias a été évaluée. Notamment, l'effet de la composition et de la nature des fibres non-adsorbantes, du degré de raffinage des fibres cellulosiques et de l'ajout de liants a été étudié. Leur impact sur les propriétés de structure du média mais également sur ses performances pour la filtration de particules de dolomite (65 000 part. Cm-3) et l'adsorption de toluène (C0 = 320 mg. M-3) pour une vitesse d'air de 0,3 m. S-1, a été analysé. Pour des médias composés de FCA et de FC, une augmentation de la teneur en FC et de leur degré de raffinage ferme la structure poreuse du média et entraîne une augmentation de son efficacité de capture des particules mais également de la perte de charge générée. L'introduction de fibres de PET et des liants associés pour assurer la tenue mécanique, diminue l'homogénéité de formation du média générant ainsi des passages préférentiels pour l'air et les polluants. Un modèle statistique reliant l'efficacité de filtration initiale des médias à leurs propriétés de structure (porosité et diamètre modal de pores inter-fibres) a été réalisé afin d'accéder à une première prédiction des performances de filtration. Les propriétés d'adsorption à l'équilibre des FCA ne sont pas altérées par la présence de fibres non-adsorbantes et de liants chimiques. Toutefois, en système dynamique, les médias possédant une moins bonne homogénéité de formation, présentent des performances en adsorption plus faibles liées aux passages préférentiels pour l’air. Les médias composés d'au moins 40 % de FCA révèlent des capacités d'adsorption à la saturation élevées (≥ 98 mg. G-1) dans les conditions non favorables étudiées (faible concentration en toluène et vitesse élevée). Aux regards des performances en filtration et en adsorption, un média composé de 50 % de FCA et de 50 % de FC avec un degré de raffinage faible (16 °SR) présente le meilleur compromis entre une efficacité initiale de filtration importante (E ≥ 40 %), une perte de charge modérée (P0 < 60 Pa pour U0 < 0,3 m. S-1) et une teneur en FCA suffisante en vue d'une utilisation en traitement combiné particules / COVIn order to obtain a system efficient for collecting both particles with an aerodynamic diameter less than 10 µm (PM10) and volatile organic compounds (VOCs), prototype fibrous media containing activated carbon fibers (ACF) associated with non-adsorptive fibers such as cellulose (CF) and polyester (PET) fibers have been developed. Influence of process operating parameters on media end-use properties was investigated. Particularly, effect of type and ratio of non-adsorptive fibers, degree of beating of cellulose fibers and addition of binders was studied. Their impact on physical properties of the medium and its performances for dolomite particle collection (65 000 part. Cm-3) and for toluene adsorption (C0 = 320 mg. M-3) for an air velocity of 0. 3 m. S-1, was analyzed. For media containing ACF and CF, an increase of CF content and their beating level leads to a less opened porous structure of the medium. As a consequence, its particle collection efficiency is improved but the associated pressure also increased. Introduction of PET fibers and associated binders decreases the medium formation quality creating some preferential paths for air and pollutants. A statistical model expressing the medium initial collection efficiency as a function of its structural properties (porosity and modal inter-fiber pores diameter) was established allowing a first prediction of filtration performances. Adsorption properties at equilibrium of ACF are not spoiled due to the presence of non-adsorptives fibers and chemical binders. Nevertheless, in dynamic system, media possessing a low formation homogeneity present lower adsorption performances due to the preferential paths. Media containing at least 40 % of ACF present high adsorption capacities (≥ 98 mg. G-1) in non-favourable conditions studied (low toluene concentration and high velocity). With regard to filtration and adsorption performances, a medium composed of 50 %w ACF and 50 %w CF with a low refining level (16 °SR) presents the best compromise between a high initial particle collection efficiency (E ≥ 40 %), a moderate pressure drop (P0 < 60 Pa for U0 < 0. 3 m. S-1) and a sufficient ACF content in order to do a combined treatment particles / VOC
8
Aissat, Aissa. "Elimination catalytique simultanée de composés organiques volatils (COV) et de particules carbonées en présence d'oxydes d'azote (NOx)". Littoral, 2011. http://www.theses.fr/2011DUNK0293.
Abstract (sommario):
La maîtrise des émissions atmosphériques de composés organiques volatils (COV), de particules carbonées et d’oxydes d’azote (NOx) constitue une préoccupation commune à de nombreuses industries utilisant des procédés de combustion. Au niveau des moyens de remédiation, les procédés catalytiques ne prennent pas suffisamment en compte la présence simultanée de ces polluants dans l’effluent à traiter. Cette étude a pour objectif d’évaluer les performances de matériaux à base d’oxydes de métaux de transition, cuivre (Cu) ou cobalt (Co), supportés sur oxyde de zirconium (ZrO2) pour l’élimination simultanée du toluène et de particules carbonées en présence de NOx. L’introduction de promoteurs alcalins dans les solides a été envisagée et l'ensemble des matériaux catalytiques a fait l'objet d'une caractérisation physico-chimique appropriée. L’activité des catalyseurs dépend de la nature des espèces oxydes de Co ou Cu en surface du support ZrO2. Les espèces dispersées d’oxyde de métal de transition sont très actives en oxydation du toluène. Par ailleurs, ces mêmes oxydes présents sous forme de cristallites, associés à un alcalin ayant un effet promoteur de contact, sont performants dans la réaction d’oxydation de particules carbonées. Ce travail considère enfin l’effet des NOx gazeux, leur interaction avec les systèmes catalytiques considérés et leur capacité à participer à l’oxydation des COV et de particules carbonéesThe control of atmospheric emissions of volatile organic compounds (VOCs), carbonaceous particulate and nitrogen oxides (Nox) is a common concern for many industries using combustion processes. In the means of remediation, catalytic processes do not sufficiently take into account the simultaneous presence of these pollutants in the effluent. This study aims to evaluate the performance of materials based on transition metal oxides, copper (Cu) or cobalt (Co) supported on zirconium oxide (ZrO2) for the simultaneous removal of toluene and particulate carbon in the presence of Nox. The introduction of alkali promoters in solids has been considered and all the catalytic materials were physicochemical characterized. The activity of the catalysts depends on the nature of Co or Cu oxides species on the surface of ZrO2 support. Dispersed species of transition metal oxides are very active in toluene oxidation. Moreover, these oxides present as crystallites, associated with an alkali promoter effect of contact, are efficient in the oxidation reaction of carbonaceous particles. Finally, this work considers the effect of Nox, their interaction with the considered catalytic systems and their ability to participate in the oxidation of VOCs and carbonaceous particles
9
Sawka, Corinne. "Contamination des logements français en composés organiques semi-volatils en phase particulaire". Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1B033/document.
Abstract (sommario):
Les composés organiques semi-volatils (COSV) font l’objet d’une attention croissante depuis une dizaine d’années. Utilisés dans de nombreux produits et matériaux du quotidien, ils sont émis dans les bâtiments par dispersion lors de l’usage, par évaporation ou abrasion. Du fait de leurs caractéristiques physico-chimiques, ces composés se répartissent à la fois dans l’air, en phases gazeuse et particulaire, et dans les poussières déposées au sol, sur le mobilier et les objets. Compte tenu du temps passé par la population dans les bâtiments, en particulier par les populations sensibles comme les enfants, les femmes enceintes et les personnes âgées, l’exposition à ces substances mérite d’être documentée, tenant compte des voies d’exposition en jeu : inhalation, ingestion et contact cutané. La thèse a porté sur les COSV présents en phase particulaire dans les logements. L’objectif de la thèse visait à exploiter les mesures de 66 COSV dans les particules en suspension de diamètre inférieur à 10 µm (PM10) et de 48 COSV dans les poussières au sol de taille inférieure à 100 µm considérées comme étant celles adhérant à la peau. Ces mesures ont été réalisées dans le cadre de deux campagnes nationales : la campagne « Logements » de l’Observatoire de la qualité de l’air intérieur conduite en 2003-2005 et l’enquête Plomb-Habitat dont les prélèvements ont eu lieu en 2008-2009. Une hiérarchisation des molécules jugées prioritaires au regard de leur impact sanitaire potentiel avait permis au préalable d’établir la liste des COSV à mesurer. L’exploitation de ces données de contamination a notamment porté sur l’identification d’éventuelles spécificités françaises au regard des molécules en présence et/ou des concentrations mesurées. Elle a permis de mettre en lumière un ensemble de facteurs déterminants de l’exposition (influence de la taille des particules, du type de poussières collectées, de leur bioaccessibilité), qui ne sont pas toujours considérés et qui limitent par ailleurs la comparabilité des résultats. Les concentrations mesurées ont aussi permis d’évaluer rétrospectivement la hiérarchisation sanitaire et d’en confirmer la pertinence. Les concentrations des COSV quantifiés à la fois dans l’air et au sol ont été mises en perspective afin d’examiner dans quelle mesure les particules en suspension et les poussières déposées sont similaires en termes de concentrations et de mélanges de COSV en présence. Enfin, l‘estimation des doses d’exposition aux COSV à partir d’équations simples, de variables humaines d’exposition et des données de contamination a permis une première évaluation des contributions respectives de l’inhalation et de l’ingestion aux expositions domestiques des enfants et adultes à ces composés en phase particulaireSemi-volatile organic compounds (SVOCs) refer to a broad spectrum of molecules from different chemical families that have numerous properties. They can be used as pesticides, plasticizers, flame retardants, surfactants, lubricants, etc. Consequently, they are introduced in numerous applications in buildings or used daily by the entire population. Once emitted through evaporation or abrasion in the indoor environment or introduced from the outdoors, their chemical or biological degradation is limited, and they persist indoors. This persistence also explains why some SVOCs that were banned a few years ago are still detected in the air and dust inside buildings. In indoor environments, SVOCs are divided between the gas phase, airborne particles, and dust settled on floors and surfaces. SVOCs are of concern due to their established or suspected health effects and their widespread exposure through different environmental media and pathways. The objective of the thesis was to study the concentrations of 66 SVOCs on airborne particles (PM10) and 48 SVOCs in settled dust in two samples of dwellings randomly selected across France. PM10 were sampled during the nationwide housing survey carried out by the French Observatory of indoor air quality in 2003-2005. The dust samples were collected from vacuum cleaner bags during a nationwide survey carried out in French dwellings where at least one child aged 6 months to 6 years lived (2008-2009). The SVOCs to be analyzed had prior been selected using a ranking method based on their toxicity and indoor concentrations. The data analysis focused in particular on the identification of French specificities in terms of detected molecules and measured concentrations. It highlighted some determinants of exposure, e.g., influence of particle size, type of dust collected, dust bioaccessibility, which are not always considered and limit the comparability of results. The measured concentrations were also used to assess the health ranking implemented prior to this work and to confirm its relevance. The concentrations measured both in the air and in settled dust were compared to study the similarities in terms of concentrations and SVOC mixtures. Finally, the exposure doses to SVOCs were calculated for both a child and an adult to assess the respective contributions of inhalation and ingestion to these compounds in particulate phase in dwellings
10
Lorimier, Céline. "Traitement combiné de composés organiques volatils et de particules sur média fibreux : applications au traitement de l'air". Nantes, 2005. http://www.theses.fr/2005NANT2102.
Libri sul tema "Particules volatiles":
1
Laboratory, Occupational Medicine and Hygiene. Coal tar pitch volatiles: measurement of particulates and cyclohexane soluble materialin air: Laboratory method using filters and gravimetric estimation. Bootle: Health and Safety Executive, 1990.
2
Church, Jennifer. Boundary Problems. A cura di K. W. M. Fulford, Martin Davies, Richard G. T. Gipps, George Graham, John Z. Sadler, Giovanni Stanghellini e Tim Thornton. Oxford University Press, 2013. http://dx.doi.org/10.1093/oxfordhb/9780199579563.013.0031.
Abstract (sommario):
Many psychiatric disorders involve problems with the recognition and preservation of personal boundaries. Philosophy can help to clarify what is at stake, both socially and phenomenologically, in drawing such boundaries. In particular, assignments of responsibility and determinations of loss are deeply implicated in the determination of personal boundaries. Understanding these implications can help make sense of the volatile emotions of borderline personality disorder, for example, and it can clarify what is missing from DSM descriptions more generally.
3
Brewster, David, a cura di. Introduction. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199479337.003.0001.
Abstract (sommario):
China and India are fast emerging as major maritime powers of the Indo-Pacific. As their wealth, power, and interests expand, they are increasingly coming into contact with each other in the maritime domain. How India and China get along in the shared Indo-Pacific maritime space—cooperation, coexistence, competition, or confrontation—may be one of the key strategic challenges for the region in the twenty-first century. The relationship between these powers is sometimes a difficult one: in particular, their security relationship is relatively volatile and there are numerous unresolved issues. Not least is China’s growing presence in the Indian Ocean where it is perceived in New Delhi to be shaping the strategic environment and forming alignments that could be used against India....
4
Fontana, Biancamaria. Interpreting the Opinion of the Majority of the Nation (1789–91). Princeton University Press, 2018. http://dx.doi.org/10.23943/princeton/9780691169040.003.0002.
Abstract (sommario):
This chapter illustrates how, on her return to Paris, Germaine de Staël had found an unstable situation, marked by growing unrest in the provinces and by increasingly volatile, ever-shifting political allegiances. She had also rapidly become the object of vicious attacks in the press, emanating principally from royalist circles. The chapter cites Staël's article, which appeared in the Journal des indépendants, and explores how it reflects the preoccupations that dominated this particular phase in her public engagement: the ambition to persuade the scattered constitutional monarchists to pursue a single, coherent policy; the aspiration to see the same divided, quarrelsome factions turn into something resembling an organized party; the search for a credible leadership; and expressing the position of the moderate majority in the assembly.
5
Dwan, David. Liberty, Equality, and Humbug. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198738527.001.0001.
Abstract (sommario):
Orwell is part of the political vocabulary of our times, yet, partly because of this popularity, what he stands for remains opaque. His writing confirms deep and widely shared intuitions about political justice, but part of its enduring fascination derives from the fact that these intuitions don’t quite add up. This book accounts for these inconsistencies by exploring the broader moral conflict at the centre of Orwell’s work and the troubled views of justice it yields. Examining five key concepts in turn—liberty, equality, solidarity, truth, and happiness—the book shows how Orwell entertained volatile views of each. He also had difficulty deciding between ideals when they clashed. Orwell’s contradictions express more than his intellectual shortcomings or complacency; they expose the peculiar difficulty of justice itself. By reading Orwell, we see that justice is a many-headed ideal that demands from us different and rival things. Examining the whole sweep of Orwell’s writings, but paying particular attention to Animal Farm and Nineteen Eighty-Four, this book shows how literature—and narrative in particular—can be a source of political wisdom.
6
Agarwal, Bina. Food Security, Productivity, and Gender Inequality. A cura di Ronald J. Herring. Oxford University Press, 2013. http://dx.doi.org/10.1093/oxfordhb/9780195397772.013.002.
Abstract (sommario):
This chapter examines the relationship between gender inequality and food security, with a particular focus on women as food producers, consumers, and family food managers. The discussion is set against the backdrop of rising and volatile food prices, the vulnerabilities created by regional concentrations of food production, imports and exports, the feminization of agriculture, and the projected effect of climate change on crop yields. The chapter outlines the constraints women face as farmers, in terms of their access to land, credit, production inputs, technology, and markets. It argues that there is substantial potential for increasing agricultural output by helping women farmers overcome these production constraints and so bridging the productivity differentials between them and male farmers. This becomes even more of an imperative, given the feminization of agriculture. The chapter spells out the mechanisms, especially institutional, for overcoming the constraints and the inequalities women face as producers, consumers, and home food managers. Institutionally, a group approach to farming could, for instance, enable women and other small holders to enhance their access to land and inputs, benefit from economies of scale, and increase their bargaining power. Other innovative solutions discussed here include the creation of Public Land Banks that would empower the smallholder, and the establishment of agricultural resource centers that would cater especially to small-scale women farmers.
7
Stedt, Jim. Talent Balancing. www.praeger.com, 2005. http://dx.doi.org/10.5040/9798216022206.
Abstract (sommario):
When the economy was booming, it was hard to find good people. winning the talent war was a popular phrase, and those individuals with the right stuff could command hefty salaries and perks. When the economy crumbled, the headhunters were sent packing. Today, companies are starting to hire again, but instead of recruiting a group of fifty, they're hiring five. They're outsourcing and hiring temps. They're replacing staff due to turnovers, retirements, and areas that were downsized, rather than expanding. They're relying on reduced HR departments and in-house managers and staff to make critical staffing decisions. Surprisingly, in this environment, good people are hard to find; the top performers are staying where they are, and it's the weak and marginal performers that make up most of the available talent pool. Talent Balancing draws from the author's 35 years in the field to present a fresh and practical approach to recruiting in today's volatile and uncertain environment. In particular, Talent Balancing will help entrepreneurs and managers without formal recruitment training navigate organizational politics, analyze current and future staffing needs, and execute a successful plan. Whether you are ramping up a new team or department or filling a temporary spot, Talent Balancing provides a wealth of insights and tools to ensure that your organization meets both immediate and long-term goals.
8
Luginbühl, Martin, e Arvi Yli-Hankala. Assessment of the components of anaesthesia. A cura di Antony R. Wilkes e Jonathan G. Hardman. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199642045.003.0026.
Abstract (sommario):
In modern anaesthesia practice, hypnotic drugs, opioids, and neuromuscular blocking agents (NMBAs) are combined. The introduction of NMBAs in particular substantially increased the risk of awareness and recall during general anaesthesia. Hypnotic drugs such as propofol and volatile anaesthetics act through GABAA receptors and have typical effects on the electroencephalogram (EEG). During increasing concentrations of these pharmaceuticals, the EEG desynchronization is followed by gradual synchronization, slowing frequency, and increasing amplitude of EEG, thereafter EEG suppressions (burst suppression), and, finally, isoelectric EEG. Hypnotic depth monitors such as the Bispectral Index™, Entropy™, and Narcotrend® are based on quantitative EEG analysis and translate these changes into numbers between 100 and 0. Although they are good predictors of wakefulness and deep anaesthesia, their usefulness in prevention of awareness and recall has been challenged, especially when inhalation anaesthetics are used. External and patient-related artifacts such as epileptiform discharges and frontal electromyography (EMG) affect the signal so their readings need careful interpretation. Their use is recommended in patients at increased risk of awareness and recall and in patients under total intravenous anaesthesia. Monitors of analgesia and nociception are not established in clinical practice but mostly remain experimental although some are commercially available. Some use EEG changes induced by noxious stimulation (EEG arousal) or quantify the frontal EMG in relation to EEG, while others are based on the sympathoadrenergic stress response. Various other devices are also discussed in this chapter.
9
Dawson, Melanie V. Edith Wharton and the Modern Privileges of Age. University Press of Florida, 2020. http://dx.doi.org/10.5744/florida/9780813066301.001.0001.
Abstract (sommario):
This project explores age-based obsessions of the modern era, situating the charting and interrogation of age among modernity’s central preoccupations, with particular attention to the gendering of old age and the creation of intergenerational conflicts. While chronological considerations privileged the young and tended to exclude those past adulthood, much of modern literature interrogated the age-based forms of standardization rooted in the era’s understanding of personal development. By focusing on the ways that age was constructed so as to uphold the ideal of a coherent, stable self, this literature interrogates theories of development that were believed to govern life trajectories, and with them, ideals about progress, often to the point of envisioning aging as a form of unwelcome dissolution. The era’s literary texts, however, complicated such views by adding to familiar figures of the flapper and the young generation a host of others that broke age thresholds: the mature youth, the youthful adult, the young middle-aged, the rejuvenate, the child bride, the aged, and the ghost. All such figures invited an interrogation of youth’s supposed ascendancy by suggesting that modernity’s age-based privileges were more varied and more widely dispersed than they seemed. If youth appeared dominant in terms of bodily forms and youthful energies, the more mature are revealed as possessing resources, experiences, and strategies that counter the assets of the young, leading to scenarios where the outcomes of intergenerational conflicts were both volatile and unexpected.
10
Schmitt-Beck, Rüdiger, Sigrid Roßteutscher, Harald Schoen, Bernhard Weßels e Christof Wolf, a cura di. The Changing German Voter. Oxford University Press, 2022. http://dx.doi.org/10.1093/oso/9780198847519.001.0001.
Abstract (sommario):
Over the past half century, the behavior of German voters has changed profoundly—at first rather gradually but during the last decade at accelerated speed. Electoral decision-making has become much more volatile, rendering election outcomes less predictable. Party system fragmentation intensified sharply. The success of the Alternative for Germany (AfD) put an end to Germany’s exceptionality as one of the few European countries without a strong right-wing populist party. Utilizing a wide range of data compiled by the German Longitudinal Election Study, the book examines changing voters’ behavior in the context of changing parties, campaigns, and media during the period of its hitherto most dramatically increased fluidity at the 2009, 2013, and 2017 federal elections. Guided by the notions of realignment and dealignment, the study addresses three questions: How did the turbulences that increasingly characterize German electoral politics come about? How did they in turn condition voters’ decision-making? How were voters’ attitudes and choices affected by situational factors that pertained to the specifics of particular elections? The book demonstrates how traditional cleavages lost their grip on voters and a new socio-cultural line of conflict became the dominant axis of party competition. A series of major crises, but also programmatic shifts of the established parties promoted this development. It led to a segmentation of the party system that pits the right-wing populist AfD against the traditional parties. The book also demonstrates the relevance of coalition preferences, candidate images as well as media and campaign effects for voters’ attitudes, beliefs, and preferences.
Capitoli di libri sul tema "Particules volatiles":
1
Morgan, Lynette. "Greenhouse produce quality and assessment." In Hydroponics and protected cultivation: a practical guide, 246–67. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789244830.0013.
Abstract (sommario):
Abstract 'Quality' of greenhouse and hydroponic produce implies suitability for a particular purpose or the degree to which certain set standards are met. Aspects of produce quality may encompass sensory properties (appearance, texture, taste and aroma), nutritive values, chemical constituents, mechanical properties, functional properties and defects. Quality standards and testing methods have been developed for most commercial crops to help ensure consumers receive produce of a suitable standard. These quality standards can range from basic grading for removal of damaged produce and for size, shape, weight and overall appearance, to analytical testing for compositional factors such as acidity, volatiles, dry matter, starch and sugars, toxins, vitamins and minerals, and others. This chapter discusses the components of crop quality, quality improvement, cultural practices to improve greenhouse produce quality (nutrient solution electrical conductivity levels, salinity and deficit irrigation), environmental conditions (including light and temperature) affecting quality of greenhouse crops, role of genetics in the quality of greenhouse-grown produce, microbial quality and food safety. Different quality testing and grading methods are described such as colour analysis, total soluble solids (Brix) testing, sensory evaluation of compositional quality, volatiles testing (aroma), texture and firmness quality assessment.
2
Morgan, Lynette. "Greenhouse produce quality and assessment." In Hydroponics and protected cultivation: a practical guide, 246–67. Wallingford: CABI, 2021. http://dx.doi.org/10.1079/9781789244830.0246.
Abstract (sommario):
Abstract 'Quality' of greenhouse and hydroponic produce implies suitability for a particular purpose or the degree to which certain set standards are met. Aspects of produce quality may encompass sensory properties (appearance, texture, taste and aroma), nutritive values, chemical constituents, mechanical properties, functional properties and defects. Quality standards and testing methods have been developed for most commercial crops to help ensure consumers receive produce of a suitable standard. These quality standards can range from basic grading for removal of damaged produce and for size, shape, weight and overall appearance, to analytical testing for compositional factors such as acidity, volatiles, dry matter, starch and sugars, toxins, vitamins and minerals, and others. This chapter discusses the components of crop quality, quality improvement, cultural practices to improve greenhouse produce quality (nutrient solution electrical conductivity levels, salinity and deficit irrigation), environmental conditions (including light and temperature) affecting quality of greenhouse crops, role of genetics in the quality of greenhouse-grown produce, microbial quality and food safety. Different quality testing and grading methods are described such as colour analysis, total soluble solids (Brix) testing, sensory evaluation of compositional quality, volatiles testing (aroma), texture and firmness quality assessment.
3
de Jong, Michiel. "Arms Exports and Export Control of the Dutch Republic 1585–1621". In NL ARMS, 289–309. The Hague: T.M.C. Asser Press, 2021. http://dx.doi.org/10.1007/978-94-6265-471-6_16.
Abstract (sommario):
AbstractThe Dutch Republic underwent a process of state formation, accelerated economic growth and military reforms during the Eighty Years War. In particular between 1585 and 1621, Dutch merchant-entrepreneurs built up a burgeoning arms industry and sector of arms exports. These exports required a system of passports, still an under-researched theme in current literature, organized by the States-General and admiralties in order to support exports to neutral and allied states, but to forestall these did not fall into enemy hands. In particular, the system of passports shows how merchants, acting as intermediaries between allies and the States-General and the admiralties, could meet the volatile demand of war materials. As a result, the supply side of the export market was oligopolistic, but the composition of the group of oligopolists varied depending on the region and the prevailing market conditions in question. From this study it can be concluded that the system of export control had only a limited effectiveness regarding the creative arms exports to Spanish Habsburg destinations, due to divergent central and local interests. However, the major part of the Dutch arms exports flowed to allies such as France, Venice, Sweden and the German protestant states. Dutch merchants provided them with batches of strategic materials and total package-deals of armaments for entire army and navy units. From 1621, the States-General supported these transactions by supplying war materials from the state arsenals fostering timely and largescale deliveries, meeting volatile demand conditions.
4
Khyzha, Artem, e Ori Lahav. "Abstraction for Crash-Resilient Objects". In Programming Languages and Systems, 262–89. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-99336-8_10.
Abstract (sommario):
AbstractWe study abstraction for crash-resilient concurrent objects using non-volatile memory (NVM). We develop a library-correctness criterion that is sound for ensuring contextual refinement in this setting, thus allowing clients to reason about library behaviors in terms of their abstract specifications, and library developers to verify their implementations against the specifications abstracting away from particular client programs. As a semantic foundation we employ a recent NVM model, called Persistent Sequential Consistency, and extend its language and operational semantics with useful specification constructs. The proposed correctness criterion accounts for NVM-related interactions between client and library code due to explicit persist instructions, and for calling policies enforced by libraries. We illustrate our approach on two implementations and specifications of simple persistent objects with different prototypical durability guarantees. Our results provide the first approach to formal compositional reasoning under NVM.
5
Alpan, Başak. "Europeanization and EU–Turkey Relations: Three Domains, Four Periods". In EU-Turkey Relations, 107–37. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70890-0_5.
Abstract (sommario):
AbstractEuropeanization is deservedly one of the most popular yet most volatile buzzwords for Turkish politics and EU–Turkey relations. This chapter takes stock of the Europeanization literature and examines the EU–Turkey relationship by referring to particular mechanisms and variants of Europeanization. The main argument is that Europeanization is a versatile and complex process covering vast areas of policy, politics, and polity, intertwined with larger domestic, regional, and global processes, which is not limited to Turkey’s EU accession. The analysis refers to particular mechanisms and variants of Europeanization in four different phases between 1963 and early 2020: In the first period, ‘Europeanization as rapprochement’, Turkey’s age-old Westernization project was consolidated through Europeanization. In the second period, ‘Europeanization as democratic conditionality’, there has been strong interest in the impact of Europeanization on particular aspects of domestic issues through conditionality and the EU’s role as a ‘democratization anchor’. In the third period, ‘Europeanization as retrenchment’, and the fourth period, ‘Europeanization as denial’, ‘Europe’ was no longer the lingua franca in the Turkish political landscape, a trend that is also associated with a ‘de-Europeanization’ turn in the literature. This does not mean that ‘Europe’ completely disappeared from domestic policy orientations, political debates, and identity negotiations. Rather, Ankara used ‘Europe’ strategically to justify actions that were criticized by the EU.
6
Zahari, Finn, Seongae Park, Mamathamba K. Mahadevaiah, Christian Wenger, Hermann Kohlstedt e Martin Ziegler. "Redox-Based Bi-Layer Metal Oxide Memristive Devices". In Springer Series on Bio- and Neurosystems, 87–114. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-36705-2_3.
Abstract (sommario):
AbstractIn a memristor or a so-called memristive device, the resistance state depends on the previous charge flow through the device. The new resistance state is stored and classifies a memristor as a non-volatile memory device. This likewise unique and simple feature qualifies memristive devices as attractive compartments with regard to the development of a universal memory and beyond von Neumann computing architectures, including in-memory computing and neuromorphic circuits. In this chapter, we present studies on two kinds of bi-layer metal oxide memristive devices with the layer sequences Nb/NbO$$_{\textrm{z}}$$ z /Al$$_2$$ 2 O$$_3$$ 3 /Nb$$_{\textrm{x}}$$ x O$$_{\textrm{y}}$$ y /Au and TiN/TiO$$_\textrm{x}$$ x /HfO$$_\textrm{x}$$ x /Au, either prepared by reactive DC-magnetron sputtering, etching and optical lithography. It is shown that the memristive properties of such devices can be engineered, which enables tailoring of the memristive devices for particular applications.
7
Höfner, Malte, e Rainer Rosegger. "A Critical Perspective on the Sharing Economy in Tourism Using Examples of the Accommodation Sector in Austria". In The Sharing Economy in Europe, 285–303. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-86897-0_13.
Abstract (sommario):
AbstractIn recent decades, services on digital platforms have become increasingly important in tourism. What started with concepts of exchange as a non- or less commodified practice of sharing accommodations (e.g., Couchsurfing) became exceedingly commodified in the platform economy on a global scale and turned into successful business models (e.g., Airbnb) with strong effects on traditional provider structures and local labour market. In Austria, the economic relevance of tourism traces back more than 100 years. Today, new forms of overnight stays, such as short-term rentals (STRs), have flooded the traditional tourism industry market with offerings in the accommodation sector and pose particular challenges in the housing market in Austrian cities. The COVID-19 crisis highlights the general volatility in tourism. Therefore, alternative business models seem to be more important than before. Discussing the relevance of hybrid sharing as a business model between market-based services and platform cooperatives in the global platform economy, domestic examples from Austria serve as an incentive for other countries to show new pathways in terms of alternative platform structures and work towards a less volatile economy. In doing so, national insights of regulations of global players and new guidelines of platform-based sharing are debated too.
8
Mattiacci, Eleonora. "Conclusions". In Volatile States in International Politics, 122—C6.P79. Oxford University PressNew York, 2023. http://dx.doi.org/10.1093/oso/9780197638675.003.0006.
Abstract (sommario):
Abstract This chapter delves into the value added of studying volatility in states’ behaviors. It is divided into three parts. The first part illuminates how understanding the root causes of volatility can stave off its worst consequences in international politics, including stifling trust and igniting escalation. The second part leverages findings in this book on the connection between power and interests on the one hand and volatility on the other to illuminate future paths of research on mixed findings regarding key issues such as compliance, reputation, credible commitments, and audience costs. Finally, the chapter charts out the ways in which the theory and findings in this book can help extend the study of volatility in International Relations beyond volatility in states’ behaviors. In particular, it points toward the study of nonstate actors and of the international system itself.
9
David, Victor, e Serban C. Moldoveanu. "Recent Applications of Gas Chromatography in Bioanalysis". In Recent Advances in Gas Chromatography [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.106894.
Abstract (sommario):
Bioanalysis involves a broad range of chemical analyzes. These analyzes include that of biotics, such as natural components of living organisms, as well as xenobiotics, such as drugs and their metabolites in biological systems. Because many biotics and xenobiotics are not volatile molecules, the main technique for bioanalysis is high-performance liquid chromatography (HPLC) and the limitation of GC utilization is caused by the fact that GC is applicable only to volatile samples. However, gas chromatography (GC) in particular coupled with mass spectrometry (MS) as detection is also a very useful technique in bioanalysis. A considerable number of analytes in bioanalysis are volatile or can be made volatile following, for example, derivatization. As a result, GC (and GC/MS) are commonly utilized for the analysis of biotics, such as amino acids, fatty acids, various metabolites in biological fluids, and in particular of a large number of xenobiotics, such as drugs, drug metabolites, toxicants, and certain metabolic compounds caused by toxicants. The chapter will present progress in the GC methodology for extending its applicability to bioanalysis and will provide a review of more recent applications.
10
Petrus, Mioara, Cristina Popa e Ana-Maria Bratu. "Organic Volatile Compounds Used in Type 2 Diabetes". In Type 2 Diabetes [Working Title]. IntechOpen, 2020. http://dx.doi.org/10.5772/intechopen.94752.
Abstract (sommario):
Analysis of volatile organic compounds (VOCs) in exhaled breath is non-invasive method and appears as a promising tool for metabolic monitoring. Diabetes is a complex syndrome, metabolic diseases that is characterized by hyperglycemia associated with major changes in lipids and proteins. The pathophysiology of the link between diabetes, hypertension, inflammatory syndrome and oxidative stress is complex. We conducted a study and applied quantitative analysis of exhaled ethylene and ammonia in patients with type 2 diabetes mellitus (T2DM) and a healthy control group. For breath gas analysis, a very sensitive CO2 laser photoacoustic spectroscopy (CO2LPAS) was applied. The concentration of exhaled VOCs differed between T2DM patients and healthy group, in particular, T2DM patients exhaled significantly higher amounts of ethylene and ammonia compared to healthy control group. The data obtained by the CO2LPAS system revealing that the increased breath VOCs has a close relationship with high glucose levels and with healthy complications.
Atti di convegni sul tema "Particules volatiles":
1
Chen, Linghong, Zhenyan Pan, Kefa Cen, Kunzan Qiu e Gerard Grehan. "Laser-Induced Emission of Ultrafine Particulates Evolved by Pulverized Coal Pyrolysis". In ASME 2011 Power Conference collocated with JSME ICOPE 2011. ASMEDC, 2011. http://dx.doi.org/10.1115/power2011-55449.
Abstract (sommario):
The importance of on line measurement of ultrafine particulates in pulverized coal flames is mainly due to the detection of ultrafine particulate in the effluent for pollution control, and the quantification of fuel burnout in real time within a boiler for improved understanding of the flame heat transfer soot modeling as well. A method has been investigated using laser-heated emission within an O2-free flame which provides a continuous in situ measurement of ultrafine particles during high-temperature pulverized coal pyrolysis. Bituminous coal particles are entrained by nitrogen along the centerline of a laminar flow flat flame burner, where a hydrogen-air flame under fuel-rich condition is used as a heat source. The temperatures of the hydrogen flame were measured by a finite-wire silica-coated Platinum-Rhodium type B Thermocouple. Volatiles released during the coal pyrolysis form a cloud of ultrafine particles at high temperature. A pulse laser sheet introduced to the flame heats the ultrafine particles to incandescent temperatures. The time-resolved laser-induced emission signals with different incident laser-pulse fluences were evaluated. The volume faction of ultrafine particles was associated with the peak value of the signals, and the mean particle size characterized by a time constant of the exponential signal decay. A strong dependence of the characteristic peak value and emission time constant during laser-heated particle cooling from the measured coal particle class could be determined. Specialties in signal evaluation due to residence time in the hydrogen flame for two sizes of coal particles are discussed.
2
Buffone, C., e K. Sefiane. "Marangoni Convection in Capillary Tubes Filled With Volatile Liquids". In ASME 2003 1st International Conference on Microchannels and Minichannels. ASMEDC, 2003. http://dx.doi.org/10.1115/icmm2003-1082.
Abstract (sommario):
The work is an experimental investigation of the evaporation process from a liquid meniscus formed in capillary tubes of various sizes (ranging from 200 to 900 μm). The results have been compared with those of a previous analytical work and show how the strong convection in the liquid phase is responsible for the discrepancy found. In the analytical prediction the evaporation process is sustained only by diffusion and in this model the meniscus position vs. time is a linear function of the tube size; instead, our experimental results show how this parameter is inversely correlated with the pore size. The surface roughness of the tubes was characterized and particular care has been devoted to the capillaries’ cleaning procedure from which wetting properties are strongly dependent. Marangoni convection prevails at tube sizes less than one millimeter in diameter as in the present case, while at larger sizes a coupling between Marangoni and Rayleigh convection is expected. The Marangoni roll of thoroidal shape in the liquid phase has been visualized and characterized using seeding particles. As pointed out clearly in the present study, Marangoni convection enhances the heat-mass transfer from a pore.
3
Han, Muyue, Jing Zhao e Lin Li. "Emissions of Volatile Organic Compounds From 4D Printing and Associated Control Strategies Towards Workplace Safety". In ASME 2021 16th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/msec2021-63540.
Abstract (sommario):
Abstract The integration of additive manufacturing technologies with stimuli-responsive shape memory materials allows the dynamic self-adaptation of fabricated parts upon exposure to external stimulations. The additional dimension of time inspires the concept of four-dimensional printing technology. However, the emerging feedstock materials and the employment of external stimuli in 4D printing are also associated with new workplace hazards and occupational health concerns. Current evaluation studies on additive manufacturing are mainly focused on the safety and health effects that originated from the part production phase and cannot be directly applied in 4D printing processes. In this study, the emissions of volatile organic compounds from stereolithography-based 4D printing process with thermo-responsive materials are targeted as the potential safety concern. Real-time total volatile organic compound monitoring is conducted during various production phases to align the emission sources with critical operating activities, including both operator interventions and machine operations. Comparative experiments are performed to evaluate the effectiveness of proposed emission control strategies. In particular, alterations in operation procedures such as stirring speed in material mixing and post-printing stimulation method can contribute positively to air emission control during manual operations. In addition, the installation of activated carbon fiber filters inside the machine build chamber can lead to a significant reduction of air emissions during part fabrication with an overall total volatile organic compound concentration reduction of 58.91%.
4
Gaina, Boris, e Eugeniu Alexandrov. "Compușii chimici volatili și noile genotipuri de viță-de-vie". In VIIth International Scientific Conference “Genetics, Physiology and Plant Breeding”. Institute of Genetics, Physiology and Plant Protection, Republic of Moldova, 2021. http://dx.doi.org/10.53040/gppb7.2021.36.
Abstract (sommario):
In the process of development and ripening of berries, depending on fluctuations in climatic fac-tors, an aroma characteristic of the genotype of grapevine is formed, and as a result of processing the bunches, a bouquet of young wine is formed. Grapevine berries contain, for the most part, the same aro-matic chemical compounds, however, the specific aroma is due not only to their different mass concentra-tion, but also to their ratio in the aromatic complex of each genotype. The specific shade of aromas of a particular genotype and the accent of aromas of a particular genotype depends to a greater extent on the transmission of hereditary traits from parental pairs of crossing, the degree of ripening of berries, the phy-tosanitary level of plantings and on the influence of factors of the growing environment. The purpose of this study is to determine and comparative analysis of aromatic compounds in the berries of the rhizogen-ic interspecific genotype of grapevine Amethyst with the same complex of volatile compounds of the classic varieties Feteasca Neagră, Cabernet-Sauvignon, Malbec.
5
Levendis, Yiannis A. "Emissions From Direct or Indirect Combustion of Tire-Derived-Fuel". In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-66541.
Abstract (sommario):
This paper reports on partial results of a comprehensive laboratory investigation on the emissions from batch-combustion of tire-derived fuel (TDF) in the form of waste-tire chips placed in fixed beds. TDF is a fuel of technological interest based on its high-energy content, in the range of 30–39 MJ/kg. However, there have been issues with health-hazardous emissions from the combustion of tires. The overall goal of the investigation has been to identify techniques and conditions that minimize toxic emissions. This particular work contrasts emissions from direct combustion of TDF with those from indirect combustion, i.e., staged pyrolysis of TDF followed by combustion of the pyrolyzates. Generation of a pyrolysis gas from TDF allows for effective mixing of this gas with air and, hence, for better control of the subsequent combustion and minimization of pollutant emissions. Emissions CO2, CO, semi-volatile polycyclic aromatic hydrocarbons (PAH) and particulates were monitored herein. Results illustrated that the staged pyrolysis-oxidation approach, albeit more complicated, has the potential for low health-hazardous emissions from waste tire-to-energy plants. It produced drastically less PAH (by up to an order of magnitude) and particulates (by more than an order of magnitude). However, it produced more CO and NOx (by factors of 2–5). The presence of an afterburner (1 s residence time at 1000 °C), curtailed the emissions of CO and, interestingly, it was capable of nearly-equalizing the final emissions of PAH from the two different modes of combustion. However, the afterburner treatment was not as successful in reducing the emissions of particulates and, as a result, the indirect combustion of TDF produced an effluent with a drastically lower particulate loading.
6
Lawson, Yvonne, Christopher M. Brookes, Carl J. Steele e Mark J. Sarsfield. "Understanding Potential Release Mechanisms of Volatile Ruthenium During the Vitrification of High Level Waste". In ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16288.
Abstract (sommario):
In the U.K., High Level Waste from reprocessing operations is vitrified at the Sellafield Waste Vitrification Plant (WVP). A small number of the nuclides present in the waste have the potential to volatilize during vitrification. In order to prevent release of any radionuclides to the environment it is important to understand the mechanisms by which volatilization may occur and to have suitable controls in place. One element of particular concern is ruthenium, formed during the fission of nuclear fuel, which has the potential to form gaseous species such as RuO4 during the vitrification process and whose behavior must therefore be understood in order to underpin the safe operation of WVP.
7
Tugulea, Andrian. "Dinamica numărului unităților de transport ca factor de poluare a aerului atmosferic în R.D. Nord a Republicii Moldova". In Provocări şi tendinţe actuale în cercetarea componentelor naturale şi socio-economice ale ecosistemelor urbane şi rurale. Institute of Ecology and Geography, Republic of Moldova, 2020. http://dx.doi.org/10.53380/9789975891608.27.
Abstract (sommario):
Because of the growing vehicle population and the high emission rates, serious air pollution problems have become common phenomenon in modern life. Emissions from the transport sectors (land-based transport, shipping, and aviation) significantly contribute to this effect. This is of particular relevance in view of comparatively large growth rates of these sectors. Climatically active components of transport emissions include: the long-lived greenhouse gas CO2; shortlived trace gases, in particular nitrogen oxides (NOx = NO + NO2), carbon monoxide (CO), and volatile organic compounds (VOC), which can induce changes in the concentration of the greenhouse gases ozone (O3) and methane (CH4); as well as aerosol particles (e.g., soot) and aerosol precursor gases (e.g., SO2 or the aforementioned NOx and VOC), which can cause important modifications of clouds and radiation.
8
Qin, Tongran, Minami Yoda e Roman O. Grigoriev. "The Effect of Noncondensables on the Buoyancy-Thermocapillary Convection in Confined and Volatile Fluids". In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-40124.
Abstract (sommario):
Convection in confined layers of volatile liquids has been studied extensively under atmospheric conditions. Recent experimental results [1] have shown that removing most of the air from a sealed cavity significantly alters the flow structure and, in particular, suppresses transitions between the different convection patterns found at atmospheric conditions. Yet, at the same time, this has almost no effect on the flow speeds in the liquid layer. To understand these results, we have formulated and numerically implemented a detailed transport model that accounts for mass and heat transport in both phases as well as the phase change at the interface. Surprisingly, the numerical simulations show that noncondensables have a large effect on buoyancy-thermocapillary flow at concentrations even as low as 1%, i.e., much lower than those achieved in experiment.
9
Molière, M., F. Geiger, E. Deramond e T. Becker. "Volatile, Low Lubricity Fuels in Gas Turbine Plants: A Review of Main Fuel Options and Their Respective Merits". In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-231.
Abstract (sommario):
While natural gas is achieving unrivalled penetration in the power generation sector, especially in gas-turbine combined cycles (CCGT), an increasing number of alternative fuels are in a position to take up the ground left vacant by this major primary energy. In particular, within the thriving family of liquid fuels, the class of volatile products opens interesting prospects for clean and efficient power generation in CCGT plants. Therefore, it has become a necessity for the gas turbine industry to extensively evaluate such new fuel candidates, among which: naphtha’s; kerosines; gas condensates; Natural Gas Liquids (NGL) and alcohols are the most prominent representatives. From a technical standpoint, the success of such projects requires both a careful approach to several specific issues (eg: fuel handling & storage, operation safety) and a clear identification of technological limits. For instance, while the purity of gas condensates meets the requirements of heavy-duty technologies, it generally appears unsuitable for aeroderivative machines. This paper offers a succinct but comprehensive technical approach and overviews some experience acquired in this area with heavy duty gas turbines. Its aim is to inform gas turbine users/engineers and project developers who envisage volatile fuels as alternative primary energies in gas turbine plants.
10
Golchert, Brian M., Shen-Lin Chang e C. Q. Zhou. "The Effect of Gases Emitted From Batch/Glass Reactions on the Combustion Space Flow Field". In ASME 2003 Heat Transfer Summer Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/ht2003-47440.
Abstract (sommario):
The concept of ‘coupling’ a combustion space CFD code to a code that models the molten glass flow is not a new idea. However, this concept has been limited to an energy coupling; the heat flux calculated in the combustion space model is used to drive the glass melt while the calculated surface temperature is used in the radiative heat transport calculation in the combustion space computation. In reality, there is significant mass (mostly gas) transport from the batch/molten glass into the combustion space. This is an important phenomenon to be modeled since these gases, particulates and volatiles will be removed from the combustion chamber and hence raise environmental considerations. In addition, these released gases have a distinct influence on the flow field in the combustion space. The ANL Glass Furnace Model has been augmented to calculate the chemical reactions that release gases in the batch and in the melt. This work presents preliminary results indicating the effect of these gases on the combustion space.
Rapporti di organizzazioni sul tema "Particules volatiles":
1
Galili, Gad, Harry J. Klee e Asaph Aharoni. Elucidating the impact of enhanced conversion of primary to secondary metabolism on phenylpropanoids secondary metabolites associated with flavor, aroma and health in tomato fruits. United States Department of Agriculture, gennaio 2012. http://dx.doi.org/10.32747/2012.7597920.bard.
Abstract (sommario):
• Targeted manipulating Phenylalanine (Phe) synthesis is one of the most powerful strategies to boost the biologically and economically important secondary metabolites, including phenylpropaniods, aromatic volatiles and specialized secondary metabolites. • Over-expression of the petunia MYB transcript factor, ODORANT1 (ODO1), results in significant alterations of the levels of specific phenylpropanoid compounds in plants. • Our previous studies indicated that ectopic expression of the feedback-insensitive AroG could break the bottleneck between primary and secondary metabolisms in tomato, thereby aiding in producing new tomato composition and identifying the unknown roles of multiple key regulators in specialized metabolism. Therefore, combining the AroG and ODO1 is of particular interest for elucidating the combined regulatory role of both of these genes in the Phe metabolic pathway, as well as generating tomato fruits that contain higher levels of secondary metabolites. • Here, we performed the LC-MS and GC-MS analyses on fruits of four tomato genotypes, namely, wild type tomato fruits as well as tomato fruits expressing the AroG, ODO1 and the combination of AroG plus ODO1 (AO) genotypes. Our results elaborated that the levels of many of the Phe-derived metabolites were predominately altered in fruits of the AO genotype, compared to tomato fruits expressing either AroG or ODO1 individually. The levels of most of these metabolites were significantly stimulated, such as Tyrosine (Tyr), coumaric acid and ferulic acid derived metabolites, but the levels of some important secondary metabolites were reduced in the AO transgenic genotypes as compared to either AroG or ODO1 lines. Nevertheless, our results also revealed that the levels of aromatic volatiles were obviously down regulated in the AO, compared to that in AroG transgenic fruits, but were boosted while compared to the wild type and ODO1 transgenic fruits. • Our results suggest that ODO1 expression may also have a negative effect on the production of some of the aromatic volatiles in tomato fruits, indicating that ODO1 acts as an important regulator of the shikimate pathway, which leads to the production of the aromatic amino acids and secondary metabolites derived from them. Key words: AroG, ODO1, tomato, metabolism, shikimate pathway
2
BUHARI, Lateef Oluwafemi. Understanding the Causes of Electoral and Political Violence in Ekiti State, Nigeria: 2007-2010. Intellectual Archive, marzo 2021. http://dx.doi.org/10.32370/ia_2021_03_17.
Abstract (sommario):
All over the world, elections are the litmus test of democracies. They also serve to consolidate political stability in a given polity just as they have the propensity to engender conflict and violence. Though there is usually competition over the control of the machineries of power, the turning point of that competition into violence becomes imperative in discerning the causes, both remote and immediate of such violence. In the light of the above, this paper notes the volatile nature of elections in Nigeria at large and Ekiti State in particular between 2007 and 2010. It examines plethora of factors leading to electoral fraud and political violence in the state. It further analyses the role of various stakeholders in political violence in the state.
3
Kanczuk, Fabio, e Laura Alfaro. Sovereign Debt: Indexation and Maturity. Inter-American Development Bank, aprile 2006. http://dx.doi.org/10.18235/0010858.
Abstract (sommario):
In this paper we review the literature on sovereign debt with particular emphasis on indexation and maturity and the main policy proposals related to these topics. We also advance some implications derived from our work. In Alfaro and Kanczuk (2005a, b, c), we modeled sovereign debt as a contingent claim following the framework developed by Grossman and Van Huyck (1988). Our framework, however, recognizes that contingent debt might be associated with incentive problems. Applying this framework to the study of the sustainability of sovereign debt, the tradeoff between nominal and indexed debt, and the optimal debt maturity, we find some of the proposals advanced in the literature regarding lengthening debt maturity and issuing nominal debt to be unsustainable in emerging (volatile) economies.
4
Perry, Guillermo, e Sebastián Bustos. The Effects of Oil and Mineral Taxation on Non-commodity Fiscal Revenues. Inter-American Development Bank, settembre 2012. http://dx.doi.org/10.18235/0011408.
Abstract (sommario):
This paper shows, first, that non-commodity revenues are more volatile in oil- and mineral-rich countries and that quality of institutions is associated with lower volatility. We investigate the channels through which oil and mineral revenue volatility lead to non-commodity revenues volatility, and find that when oil and fiscal revenues increase (decrease), non-commodity revenues are reduced (increased) discretionally, and that this substitution effect is larger and faster than an indirect positive income effect through increased public expenditures and GDP. Latin American oil- and mineral-rich countries appear, though, to behave differently. In particular, most of them show increased non-commodity revenues pari passu with increased oil and mineral revenues during the last decade. These findings have consequences for the overall volatility of public expenditures and the effectiveness of automatic tax stabilizers in oil- and mineral-rich countries.
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Blyde, Juan S., Armando Castelar Pinheiro, Eduardo Fernández-Arias e Christian Daude. Competitiveness and Growth in Brazil. Inter-American Development Bank, marzo 2010. http://dx.doi.org/10.18235/0008992.
Abstract (sommario):
In the first eight decades of the 20th century, Brazil ranked among the countries with highest growth rates in the world. During the period 1930-80, in particular, it managed to reduce its per capita income gap vis-à-vis industrialized economies and seemed poised to escape underdevelopment early in this century. However, this dream never materialized; Brazil's growth performance deteriorated sharply over the following quarter century, never fully recovering from the second oil shock and the foreign debt crisis. In this period Brazil experienced much lower and more volatile growth, with its long-term annual growth rate (ten-year moving average) fluctuating in the 2% to 3% range, well below the 6% to 10% range that prevailed in 1950-80. Brazil reacted by embarking on reforms, from trade liberalization to changes in fiscal and social policies. Policies improved, especially after price stabilization, in 1994, and, if anything, have been better than through most the high growth period, but apparently to no avail. Something happened in this later period that prevented Brazil from regaining the rapid growth that it had exhibited previously. What might it have been?
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Stickney, Christy. Many Paths to a Home: Emerging Business Models for Latin America and the Caribbean's Base of the Pyramid. Inter-American Development Bank, giugno 2014. http://dx.doi.org/10.18235/0006231.
Abstract (sommario):
The lack of adequate housing is a problem throughout Latin America and the Caribbean (LAC). Almost 40 percent of families in the region live in a house beyond repair, have no title, or lack water, sewerage, electricity, adequate building materials, or space. It is estimated that by 2015, that number will increase by 10 percent. Only an investment of at least $310 billion will close the region's current housing gap, that is 7.8 percent of LAC's GDP. The demand for improved housing among the base of the pyramid (BOP) has been consistently strong and represents a relatively steady proportion of the overall income of this segment of the population. Yet the supply of innovative and tailored solutions continues to be limited. This report presents and analyzes promising business models that are enabling companies and other organizations to provide services and products to the BOP and in doing so help address the region's pressing housing deficit. The business models show that BOP families have both the willingness and the economic capacity to make a down payment and pay monthly installments for a finished housing solution. They also demonstrate that BOP families can afford to take out a loan for home construction or improvements if financial products are designed to take into account their particular circumstances, which include labor informality or low formal wages, lack of appropriate collateral, and a volatile wage-earning scheme. Most importantly, these models expose the vast opportunities for the private sector to enter and serve the BOP market. Demand at the BOP is latent and growing, and business models with the potential to serve this market segment are in need of adequate financing. This shows that the market opportunity is there for developers, suppliers of construction materials, financial institutions, and impact investors.
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Yedidia, I., H. Senderowitz e A. O. Charkowski. Small molecule cocktails designed to impair virulence targets in soft rot Erwinias. Israel: United States-Israel Binational Agricultural Research and Development Fund, 2020. http://dx.doi.org/10.32747/2020.8134165.bard.
Abstract (sommario):
Chemical signaling between beneficial or pathogenic bacteria and plants is a central factor in determining the outcome of plant-microbe interactions. Pectobacterium and Dickeya (soft rot Erwinias) are the major cause of soft rot, stem rot, and blackleg formed on potato and ornamentals, currently with no effective control. Our major aim was to establish and study specific bacterial genes/proteins as targets for anti-virulence compounds, by combining drug design tools and bioinformatics with experimental work. The approach allowed us to identify and test compounds (small molecules) that specifically interfere with the activities of these targets, by this impairing bacterial virulence. Two main targets were selected within the frame of the BARD project. The first is the ATP-binding cassette (ABC) transporters and methyl-accepting chemotaxis proteins (MCP) that have been characterized here for the first time in Pectobacteriaceae, and the second is the quorum sensing (QS) machinery of Pectobacterium with its major proteins and in particular, the AHL synthase ExpI that was identified as the preferred target for inhibition. Both systems are strongly associated with bacterial virulence and survival in planta. We found that Pectobacteriaceae, namely Dickeya and Pectobacterium, encode more ABC transporters and MCP in their genomes, compared to other bacteria in the order. For MCP, soft rot Pectobacteriaceae not only contain more than 30 MCP genes per strain, but also have more diverse ligand binding domains than other species in the Enterobacteriales. These findings suggest that both ABC transporters and MCP are important for soft rot Pectobacteriaceae pathogenicity. We now have a selection of mutants in these proteins that may be further explored to understand their direct involvement in virulence. In parallel, we studied the QS central proteins in pectobacteria, the signaling molecule N-acyl-homoserine lactone synthase, ExpI, and the response regulator ExpR, and established their phylogenetic relations within plant pathogenic Gram negative bacteria. Next, these proteins were used for virtual screening of millions of compounds in order to discover new compounds with potential to interfere with the QS machinery. Several natural compounds were tested for their interference with virulence related traits in Pectobacterium and their capability to minimize soft rot infections. Our findings using microcalorimetric binding studies have established for the first time direct interaction between the protein ExpI and two natural ligands, the plant hormone salicylic acid and the volatile compound carvacrol. These results supported a model by which plants interfere with bacterial communication through interkingdom signaling. The collaborative project yielded two research papers and a comprehensive review, which included new computational and bioinformatics data, in Annu. Rev. Phytopathol., the highest ranked journal in phytopathology. Additional two papers are in preparation. In order to transform the fundamental knowledge that have been gained during this collaborative BARD project into agricultural practice, to control soft rot bacteria, we have submitted a continual project.
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Chandrasekhar, C. P. The Long Search for Stability: Financial Cooperation to Address Global Risks in the East Asian Region. Institute for New Economic Thinking Working Paper Series, marzo 2021. http://dx.doi.org/10.36687/inetwp153.
Abstract (sommario):
Forced by the 1997 Southeast Asian crisis to recognize the external vulnerabilities that openness to volatile capital flows result in and upset over the post-crisis policy responses imposed by the IMF, countries in the sub-region saw the need for a regional financial safety net that can pre-empt or mitigate future crises. At the outset, the aim of the initiative, then led by Japan, was to create a facility or design a mechanism that was independent of the United States and the IMF, since the former was less concerned with vulnerabilities in Asia than it was in Latin America and that the latter’s recommendations proved damaging for countries in the region. But US opposition and inherited geopolitical tensions in the region blocked Japan’s initial proposal to establish an Asian Monetary Fund, a kind of regional IMF. As an alternative, the ASEAN+3 grouping (ASEAN members plus China, Japan and South Korea) opted for more flexible arrangements, at the core of which was a network of multilateral and bilateral central bank swap agreements. While central bank swap agreements have played a role in crisis management, the effort to make them the central instruments of a cooperatively established regional safety net, the Chiang Mai Initiative, failed. During the crises of 2008 and 2020 countries covered by the Initiative chose not to rely on the facility, preferring to turn to multilateral institutions such as the ADB, World Bank and IMF or enter into bilateral agreements within and outside the region for assistance. The fundamental problem was that because of an effort to appease the US and the IMF and the use of the IMF as a foil against the dominance of a regional power like Japan, the regional arrangement was not a real alternative to traditional sources of balance of payments support. In particular, access to significant financial assistance under the arrangement required a country to be supported first by an IMF program and be subject to the IMF’s conditions and surveillance. The failure of the multilateral effort meant that a specifically Asian safety net independent of the US and the IMF had to be one constructed by a regional power involving support for a network of bilateral agreements. Japan was the first regional power to seek to build such a network through it post-1997 Miyazawa Initiative. But its own complex relationship with the US meant that its intervention could not be sustained, more so because of the crisis that engulfed Japan in 1990. But the prospect of regional independence in crisis resolution has revived with the rise of China as a regional and global power. This time both economics and China’s independence from the US seem to improve prospects of successful regional cooperation to address financial vulnerability. A history of tensions between China and its neighbours and the fear of Chinese dominance may yet lead to one more failure. But, as of now, the Belt and Road Initiative, China’s support for a large number of bilateral swap arrangements and its participation in the Regional Comprehensive Economic Partnership seem to suggest that Asian countries may finally come into their own.
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Aharoni, Asaph, Zhangjun Fei, Efraim Lewinsohn, Arthur Schaffer e Yaakov Tadmor. System Approach to Understanding the Metabolic Diversity in Melon. United States Department of Agriculture, luglio 2013. http://dx.doi.org/10.32747/2013.7593400.bard.
Abstract (sommario):
Fruit quality is determined by numerous genetic factors that affect taste, aroma, color, texture, nutritional value and shelf life. To unravel the genetic components involved in the metabolic pathways behind these traits, the major goal of the project was to identify novel genes that are involved in, or that regulate, these pathways using correlation analysis between genotype, metabolite and gene expression data. The original and specific research objectives were: (1) Collection of replicated fruit from a population of 96 RI lines derived from parents distinguished by great diversity in fruit development and quality phenotypes, (2) Phenotypic and metabolic profiling of mature fruit from all 96 RI lines and their parents, (3) 454 pyrosequencing of cDNA representing mRNA of mature fruit from each line to facilitate gene expression analysis based on relative EST abundance, (4) Development of a database modeled after an existing database developed for tomato introgression lines (ILs) to facilitate online data analysis by members of this project and by researchers around the world. The main functions of the database will be to store and present metabolite and gene expression data so that correlations can be drawn between variation in target traits or metabolites across the RI population members and variation in gene expression to identify candidate genes which may impact phenotypic and chemical traits of interest, (5) Selection of RI lines for segregation and/or hybridization (crosses) analysis to ascertain whether or not genes associated with traits through gene expression/metabolite correlation analysis are indeed contributors to said traits. The overall research strategy was to utilize an available recombinant inbred population of melon (Cucumis melo L.) derived from phenotypically diverse parents and for which over 800 molecular markers have been mapped for the association of metabolic trait and gene expression QTLs. Transcriptomic data were obtained by high throughput sequencing using the Illumina platform instead of the originally planned 454 platform. The change was due to the fast advancement and proven advantages of the Illumina platform, as explained in the first annual scientific report. Metabolic data were collected using both targeted (sugars, organic acids, carotenoids) and non-targeted metabolomics analysis methodologies. Genes whose expression patterns were associated with variation of particular metabolites or fruit quality traits represent candidates for the molecular mechanisms that underlie them. Candidate genes that may encode enzymes catalyzingbiosynthetic steps in the production of volatile compounds of interest, downstream catabolic processes of aromatic amino acids and regulatory genes were selected and are in the process of functional analyses. Several of these are genes represent unanticipated effectors of compound accumulation that could not be identified using traditional approaches. According to the original plan, the Cucurbit Genomics Network (http://www.icugi.org/), developed through an earlier BARD project (IS-3333-02), was expanded to serve as a public portal for the extensive metabolomics and transcriptomic data resulting from the current project. Importantly, this database was also expanded to include genomic and metabolomic resources of all the cucurbit crops, including genomes of cucumber and watermelon, EST collections, genetic maps, metabolite data and additional information. In addition, the database provides tools enabling researchers to identify genes, the expression patterns of which correlate with traits of interest. The project has significantly expanded the existing EST resource for melon and provides new molecular tools for marker-assisted selection. This information will be opened to the public by the end of 2013, upon the first publication describing the transcriptomic and metabolomics resources developed through the project. In addition, well-characterized RI lines are available to enable targeted breeding for genes of interest. Segregation of the RI lines for specific metabolites of interest has been shown, demonstrating the utility in these lines and our new molecular and metabolic data as a basis for selection targeting specific flavor, quality, nutritional and/or defensive compounds. To summarize, all the specific goals of the project have been achieved and in many cases exceeded. Large scale trascriptomic and metabolomic resources have been developed for melon and will soon become available to the community. The usefulness of these has been validated. A number of novel genes involved in fruit ripening have been selected and are currently being functionally analyzed. We thus fully addressed our obligations to the project. In our view, however, the potential value of the project outcomes as ultimately manifested may be far greater than originally anticipated. The resources developed and expanded under this project, and the tools created for using them will enable us, and others, to continue to employ resulting data and discoveries in future studies with benefits both in basic and applied agricultural - scientific research.