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1
Manaranche, Louis. "Stanislas Fumet (1896-1983). Au service d’une génération intellectuelle." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUL116.
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Stanislas Fumet (1896-1983) est un intellectuel catholique dont le rôle, crucial dans des domaines multiples et variés, est méconnu. Éditeur dans la prestigieuse collection du « Roseau d’Or », fondateur de la revue chrétienne Temps Présent, résistant, gaulliste, homme de radio sur France Culture : toutes ces facettes de Fumet ne l’ont pas conduit à être une figure intellectuelle engagée de premier plan. Plus que par une absence de notoriété, cette réalité s’explique largement par la fonction de service, « ancillaire » selon les termes de son filleul Pierre Manent, que Fumet a occupée auprès d’une génération intellectuelle marquée en premier lieu par la figure de Jacques Maritain. Serviteur de celle-ci, Fumet est aussi progressivement devenu au fil des années l’un de ses derniers représentants, assumant un « magistère spirituel dans le temporel » (Jean-Marie Lustiger) durant des années de mutation profonde de celui-ciStanislas Fumet (1896-1983) was a Catholic intelllectual whose crucial role in many and varied domains is unrecognized. An editor of the prestigious series "Roseau d’Or", founder of the Christian journal Temps Présent, member of the Resistance, Gaullist, broadcaster for the radio station France Culture : none of these facets led to Fumet being in the foregroud of politically committed intellectuals. More than by an absence of fame, this reality can be explained by the supporting (or "ancillary" to use his godson Pierre Manent’s term) role that Fumet played to an intellectual generation marked by Jacques Maritain. Initially this generation’s servant, Fumet gradually became one of its last representatives, taking on a "spiritual magisterium in the temporal" (Jean-Marie Lustiger)
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Manaranche, Louis. "Stanislas Fumet (1896-1983). Au service d’une génération intellectuelle." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUL116.
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Stanislas Fumet (1896-1983) est un intellectuel catholique dont le rôle, crucial dans des domaines multiples et variés, est méconnu. Éditeur dans la prestigieuse collection du « Roseau d’Or », fondateur de la revue chrétienne Temps Présent, résistant, gaulliste, homme de radio sur France Culture : toutes ces facettes de Fumet ne l’ont pas conduit à être une figure intellectuelle engagée de premier plan. Plus que par une absence de notoriété, cette réalité s’explique largement par la fonction de service, « ancillaire » selon les termes de son filleul Pierre Manent, que Fumet a occupée auprès d’une génération intellectuelle marquée en premier lieu par la figure de Jacques Maritain. Serviteur de celle-ci, Fumet est aussi progressivement devenu au fil des années l’un de ses derniers représentants, assumant un « magistère spirituel dans le temporel » (Jean-Marie Lustiger) durant des années de mutation profonde de celui-ciStanislas Fumet (1896-1983) was a Catholic intelllectual whose crucial role in many and varied domains is unrecognized. An editor of the prestigious series "Roseau d’Or", founder of the Christian journal Temps Présent, member of the Resistance, Gaullist, broadcaster for the radio station France Culture : none of these facets led to Fumet being in the foregroud of politically committed intellectuals. More than by an absence of fame, this reality can be explained by the supporting (or "ancillary" to use his godson Pierre Manent’s term) role that Fumet played to an intellectual generation marked by Jacques Maritain. Initially this generation’s servant, Fumet gradually became one of its last representatives, taking on a "spiritual magisterium in the temporal" (Jean-Marie Lustiger)
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Williams, Rebecca T. "Particles in Welding Fumes." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7382.
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The purpose of this study was to investigate whether or not differing base metals and filler wires used during welding processes contributed to differing amounts of ultrafine particles (UFP) and nanoparticles being emitted during the welding procedure. The study was also conducted to determine UFP and nanoparticle exposure in the breathing zones of the welders as well as the breathing zones of pipefitters and fire watchers, who commonly sit 6ft behind the welding arc. In order to determine if UFP and NP exposures differed with base metal and filler wire, all welding processes utilized the same welding machine for metal inert gas (MIG), the same wire speed, and the same voltages during each welding process. The only variation in welding procedures were cover gases used, base metals, and filler wires.
Measurements gathered during welding procedures were conducted in the breathing zone of the welder and pipefitters consisted of UFP measurements taken by two different condensation particle counters (CPC), which operated in synchrony at the start and cessation of the welding process. NP measurements were taken by a NanoScan Scanning Mobility Particle Sizer (SMPS) and were also placed in the breathing zone of the welder. Lastly, particle characterization measurements for transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) were gathered using a filter attached to a high flow pump, which was placed in the breathing zone of the welder.
According to the results, base metal and filler wire do emit differing amounts of NP and UFP during the welding processes. Carbon steel emits the highest amount of nanoparticles, while stainless steel emits the second highest amount, and inconel emits the least. The results also concluded that welders are exposed to a greater concentration of nanoparticles and UFPs than those experienced by pipefitters who stand 6ft from the welding arc.
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Slater, Geoffrey Reginald. "Welding fume plume dispersion." Access electronically, 2004. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20050307.120815/index.html.
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Lebas, Maud Ducos de Lahitte Jacques. "Atlas radiographique du furet (Mustela putorius furo)." [S.l.] : [s.n.], 2008. http://oatao.univ-toulouse.fr/2080/1/debouch_2080.pdf.
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Berzins, Rachel. "Evolution ontogénétique des relations interindividuelles et importance de l'olfaction dans le maintien de l'organisation sociale chez le furet (Mustela furo)." Angers, 2005. http://www.theses.fr/2005ANGE0001.
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Les modalités de l'organisation sociale des carnivores solitaires sont mal connues. Le but de cette recherche est d'identifier les mécanismes proximaux responsables de l'adoption et du maintien d'un mode de vie solitaire chez les petits mustélidés avec pour modèle d'étude, le furet (Mustela furo). Afin d'évaluer l'influence du sexe, de l'âge et de la présence de la mère sur le comportement des furets, une étude détaillée de l'évolution ontogénétique des relations interindividuelles au sein de portées a été menée de leur naissance à leur dispersion. L'analyse de leur distribution spatiale au sein de grands enclos a mis en évidence l'absence d'affinités préférentielles aussi bien entre les jeunes qu'entre la mère et ses jeunes mais aussi son rôle de cohésion. Ces observations révèlent une forte tolérance et une absence d'agressivité mais aussi la faiblesse du lien social au sein des portées. L'augmentation de la distance entre les mâles en période de dispersion laisse aussi supposer l'existence d'un déclic ontogénétique. L'étude des capacités de discrimination olfactive des furets a démontré, via un procédé d'habituation-discrimination, que les furets sont capables de discriminer le marquage anal d'un individu familier d'un individu non familier. Cette capacité pourrait notamment être utilisée par les femelles qui préfèrent la proximité de mâles olfactivement familiers en période de reproduction. En effet, l'étude du comportement des furets envers des congénères familiers et non familiers a mis en évidence, qu'après une période d'isolement, les femelles se montrent plus agressives que les mâles à l'égard de congénères non familiers de même sexe. La synthèse de ces travaux montre que l'organisation sociale des petits mustélidés serait dépendante de facteurs phylogénétiques et écologiques, la période d'isolement consécutive à la dispersion se présentant comme une phase clé dans la modification des relations interindividuelles entre l'âge juvénile et l'âge adulteSocial organization modalities of solitary carnivores are not well known. The aim of this study is to identify proximate mechanisms responsible for the adoption and maintenance of a solitary life in small mustelids, using the ferret (Mustela furo) as a model. To assess the influence of sex, age and mother presence on ferret behavior, a detailed study of the ontogenetic evolution of interindividual relationships within litter has been completed from their birth through their dispersion. The analysis of their spatial distribution inside large enclosures demonstrated an absence of preferential affinities between young just as well between mother and young, but also her cohesive role. These observations have revealed a strong tolerance and an absence of aggressiveness but also the weakness of social bond within litters. The increase of distances between males during dispersal period let also suppose the existence of an ontogenetic switch. The study of the olfactory discrimination abilities of ferret by a habituation discrimination procedure has demonstrated that ferrets are able to discriminate the anal odor of a familiar individual from an unfamiliar one. Females who prefer proximity of olfactory familiar male could use this ability during the breeding period. Indeed, the study of ferret behavior towards familiar and unfamiliar conspecifics has demonstrated, after an isolation period, that females are more aggressive than males towards same-sex unfamiliar conspecifics. The synthesis of these experiments shows that the social organization of small mustelids is dependant of phylogenetic and ecological factors, with the isolation period following dispersal being a key phase in the modification of interindividual relationships between juvenile and adult age
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Zakani, Behzad. "Rheological characterization of fumed silica lubricating greases." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63863.
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Lubricating greases have been widely used for rail lubrication systems. For an efficient grease pump design, it is important to study grease shear viscosity and it is also crucial to analyze grease yielding behavior to determine its consistency on rail surface. Among all rheological properties measured through experiments, yield stress is an ill-defined property, which investigation of a reproducible method for its determination can be invaluable. As the flow properties of a material will be usually influenced by the changes in environment temperature, studying the effects of temperature on the rheological properties of grease are important.
In this study, different rheological measurements and visualization techniques, previously developed to study a wide range of materials, have been performed to characterize fumed silica based lubricating greases manufactured by L.B. Foster Rail Technologies Corp. Using commercial rheometers and different approaches to determine the yield points of these materials, it was revealed that the values obtained by curve fitting on steady-state flow curves, creep, amplitude sweep crossover and stress ramp-up were roughly similar. The microstructure of this grease was analyzed using Scanning Electron Microscope (SEM) on Cryo and non-Cryo modes. Besides visualizing a new thickener microstructure, it was shown that the heterogeneous structures developed by small fumed silica agglomerates lead to the formation of greases with higher shear viscosities. Finally, thermo-rheological analysis of these samples revealed that these materials follow neither Arrhenius equation nor time-temperature superposition principle.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
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Goerg, Kristin A. "A Study of fume particle deposition." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/5570.
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Sreekanthan, Pradeep. "Study of chromium in welding fume." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/40245.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 1997.Vita.
Includes bibliographical references (leaves 52-54).
by Pradeep Sreekanthan.
M.S.
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Farjad, Shervin. "Analysis of metal vapour generation by laser ablation." Access electronically, 2007. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20080325.110711/index.html.
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Sutherland, Robert Allan, and mikewood@deakin edu au. "Exposure to fumes and gases during welding operations." Deakin University, 1998. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20050902.143604.
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The exposure to fumes and gases is one of the hazards associated with welding operations. Apart from research conducted on the mechanism of fume and gas formation and the relationship between fume formation rates and common welding parameters, little is known about the exposure process during welding.
This research project aimed to identify the factors that influence exposure, develop an understanding of their role in the exposure process and through this understanding formulate strategies for the effective control of exposure during welding. To address these aims a literature review and an experimental program was conducted The literature review surveyed epidemiological, toxicological and exposure data. The experimental program involved three approaches, the first, an evaluation of the factors that influence exposure by assessing a metal inert gas/mild steel welding process in a workshop setting. The second approach involved the study of exposure in a controlled environment provided by a wind tunnel and simulated welding process. The final approach was to investigate workplace conditions through an assessment of exposure and control strategies in industry.
The exposure to fumes and gases during welding is highly variable and frequently in excess of the health based exposure standards. Exposure is influenced by a number of a factors including the welding process, base material, arc time, electrode, arc current, arc voltage, arc length, electrode polarity, shield gas, wire-to-metal-work distance (metal inert gas), metal transfer mode, intensity of the UV radiation (ozone), the frequency of arc ignitions (ozone), thermal buoyancy generated by the arc process, ventilation (natural and mechanical), the welding environment, the position of the welder, the welders stance, helmet type, and helmet position. Exposure occurs as a result of three processes: the formation of contaminants at or around the arc region; their transport from the arc region, as influenced by the entry and thermal expansion of shield gases, the vigorous production of contaminants, thermal air currents produced by the heat of the arc process, and ventilation; and finally the entry of contaminants into the breathing zone of the welder, as influenced by the position of the welder, the welders stance, helmet type, and the helmet position. The control of exposure during welding can be achieved by several means: through the selection of welding parameters that generate low contaminant formation rates; through the limitation of arc time; and by isolating the breathing zone of the welder from the contaminant plume through the use of ventilation, welder position or the welding helmet as a physical barrier. Effective control is achieved by careful examination of the workplace, the selection of the most appropriate control option, and motivation of the workforce.
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Pristavita, Ramona. "Transferred arc production of fumed silica : rheological properties." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99787.
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The thermal plasma production of fumed silica in a transferred arc consists of the decomposition of quartz to SiO (g) and oxygen followed by an oxidizing quench back to SiO2. The particles formed have diameters of the order of 10 to 20 nm and are linked in a three dimensional branched chain aggregate. Previous work by Addona and Munz (1999) demonstrated the technical feasibility of producing fumed silica using this method, but was unable to demonstrate the special rheological properties of the powder. The most important characteristic of fumed silica is the presence of hydroxyls on the surface of the particles, in the form of isolated hydroxyl groups, hydrogen-bonded hydroxyl groups and siloxane groups.In the present work, we studied the changes in the powder quality by varying the quench conditions used for the production of the powder and by agglomerating the obtained particles. The fumed silica was agglomerated by conveying in a length of tubing with sharp bends. The powder was characterized using BET, Viscosity tests, FT-IR, TEM, SEM and XRD. The product was compared to both a commercial product (Aerosil 200) and the material previously produced by Addona. Tests were done before and after the agglomeration experiments.
The experimental results showed that the agglomeration had no effect on the powder's rheological properties. We concluded that the smaller viscosity values obtained for the plasma produced fumed silica were due to the lack of the free hydroxyl groups from the surface of the particles.
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Labiscsak, Laszlo. "Numerical simulation of fumes evacuation in steelmaking plants." Doctoral thesis, Università degli studi di Trento, 2012. https://hdl.handle.net/11572/367658.
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Evacuation systems in steelmaking plants contribute to the security of the operators around the furnace and help to gain the emission levels stated in the environmental regulations, furthermore play a major role in the mass and heat balance of the factory. The aim of the dissertation is to study both primary and secondary emission capture systems of an electric arc furnace steelmaking plant by means of 3D computational thermal fluid dynamics calculations.
The overall performance of the post-combustion chamber, and consequently the primary line, is controlled by the size of the gap downstream the fourth hole of an electric are furnace. The impact of the opening coefficient (ratio between the gap area and the total area) on the post-combustion chamber performance has been investigated by means of a comprehensive 3D steady CFD simulation comprising radiative heat exchanges and detailed chemical reactions. It was found that there is not a unique value of the opening coefficient capable of optimizing all the relevant quantities of the evacuation process. A value of the opening coefficient in the range 0.40-0.52 appears advisable. The impact of the (mostly unknown) boundary conditions was also assessed and inefficiencies of the assumed post-combustion geometry have been highlighted.
The secondary line's capturing efficiency during the charging phase was simulated with both transient and steady-state solvers with different turbulent models, namely the standard k-e and the Large Eddy Simulation models. The results revealed that steady-state simulations provide sufficient information for designing and optimizing the geometry of the secondary capture system. The simulations also pointed out several geometries, which cause significant pressure drop and, as a result, diminish capturing ability of the canopy hood and the additional evacuation system. The boundary conditions were imposed with the help of experimental measurements in the simulated steelmaking factory.
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Labiscsak, Laszlo. "Numerical simulation of fumes evacuation in steelmaking plants." Doctoral thesis, University of Trento, 2012. http://eprints-phd.biblio.unitn.it/736/1/dissertation.pdf.
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Evacuation systems in steelmaking plants contribute to the security of the operators around the furnace and help to gain the emission levels stated in the environmental regulations, furthermore play a major role in the mass and heat balance of the factory. The aim of the dissertation is to study both primary and secondary emission capture systems of an electric arc furnace steelmaking plant by means of 3D computational thermal fluid dynamics calculations.
The overall performance of the post-combustion chamber, and consequently the primary line, is controlled by the size of the gap downstream the fourth hole of an electric are furnace. The impact of the opening coefficient (ratio between the gap area and the total area) on the post-combustion chamber performance has been investigated by means of a comprehensive 3D steady CFD simulation comprising radiative heat exchanges and detailed chemical reactions. It was found that there is not a unique value of the opening coefficient capable of optimizing all the relevant quantities of the evacuation process. A value of the opening coefficient in the range 0.40-0.52 appears advisable. The impact of the (mostly unknown) boundary conditions was also assessed and inefficiencies of the assumed post-combustion geometry have been highlighted.
The secondary line's capturing efficiency during the charging phase was simulated with both transient and steady-state solvers with different turbulent models, namely the standard k-e and the Large Eddy Simulation models. The results revealed that steady-state simulations provide sufficient information for designing and optimizing the geometry of the secondary capture system. The simulations also pointed out several geometries, which cause significant pressure drop and, as a result, diminish capturing ability of the canopy hood and the additional evacuation system. The boundary conditions were imposed with the help of experimental measurements in the simulated steelmaking factory.
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Parnaud, Christian. "Contribution à l'étude des nitrosamines dans la fumée primaire de cigarette : mise en évidence des principaux facteurs de formation." Tours, 1993. http://www.theses.fr/1993TOUR3301.
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Näslund, Sara. "Fume : Design för hållbar utveckling i köket." Thesis, Linnéuniversitetet, Institutionen för design, DE, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-10249.
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Målet med mitt examensarbete har varit att skapa en produkt som underlättar hållbar matlagning - hållbar för miljö och hälsa. I denna uppsats redogör jag för de beslut jag fattat i min designprocess. Utifrån intervjuer, ITK (Identity Tool Kit) och research om ämnet, blev det tydligare för mig vad hållbar matlagning kunde innebära. Jag beslutade att arbeta vidare med ångkokning, en metod som bland annat bevarar näringsämnen på ett bra sätt. Jag har utvärderat marknadens utbud av ångkokare och i observationer studerat matlagningsprocessen och vilka problem som kan uppstå. Resultatet blev Fume, en ångkokare som erbjuder matlagning på höjden, samtidigt som den kräver små ytor vid förvaring.
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Brew, Daniel Robert Mitchell. "Impact of silica fume on cement performance." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369734.
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Organic ion exchanger resin beads are widely used in nuclear waste technology for pond water cleanup. They accumulate radioactive Cs and Sr in service. For disposal, the beads are encapsulated in cement but their stabilisation in cement has been difficult to achieve. The ion exchangers uptake calcium and inbibe water, as a result of which they swell, cracking the cement. Nuclear Electric had previously commissioned work on non-swelling formulations. These consist of mixtures of sulfate-resisting Portland cement, calcium hydroxide and silica fume. However, concerns have been expressed about cement durability in contact with brines. This thesis had as part of its objectives, (i) determination of the probable stability of the non-swelling matrix in MgSO4 brines and (ii) the corrosion potential of stainless steel in contact with the non-swelling cement. In addition, synthesis, characterisation work was performed on the reaction product of objective (i), M-S-H gel. Its alkali sorption capacity was determined as a function of both Mg/Si ratio and alkali concentration to assess its immobilisation potential.
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Carr, Katie. "Total Fume and Heavy Metals Emission Factors Applicable to Aluminum-Lithium Alloy Welding." ScholarWorks@UNO, 2010. http://scholarworks.uno.edu/td/1201.
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From constructing buildings to manufacturing ships, welding is the structural backbone to numerous industries. With over one hundred welding techniques, primarily driven by the base metals, filler rods, electrodes, and environmental factors, welding is a major process used in industry, commerce, and service sectors. The focus of this research is to understand the fumes generated by the Tungsten Inert-Gas (TIG) welding on Aluminum-Lithium Alloy (Al-Li Alloy), estimate applicable emission factors, and identify the heavy metal concentrations of lead, manganese, and chromium. Although there are numerous metals and various welding procedures this study will focus on three main factors: 1. Base metals comprised of Aluminum Lithium Alloy 2195 and 2219 an agehardened copper containing aluminum alloy 2. Weld wire 4043 comprised of aluminum silicone and 2319 comprised of copper silicone 3. Weld techniques of Variable Polarity Plasma Arc (VVPA) and Tungsten inertgas (TIG).
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Al-Eesa, Azmi Sami Said. "Silica fume concrete in hot and temperate environments." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/6829.
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his investigation deals with the influence of hot and temperate curing environments on the hardened properties of concrete and mortar mixes. Condensed silica fume was blended with OPC as a potential alternative cementitious material to plain OPC for use in the hot Iraqi climate, in an attempt to find a cement combination that would overcome some of the durability problems experienced when using a plain OPC concrete in such an environment. Throughout the investigation two curing environments were used: the first simulating the UK temperate climate and the second simulating the hot Iraqi climate. Temperature and humidity were varied to simulate day and night time. The first stage of the experimental study was the development of a mix design method capable of producing an OPC-CSF cement concrete of a medium workability and a specific 28-days compressive strength ranging between 25 to 55 MPa, both with and without superplasticizer. Three grades of concrete strength were chosen (25,40 and 55 MPa) and the effect of four cement replacement levels (5,10,15 and 20%) of silica fume on concrete compressive strength was assessed. Test results showed that CSF was relatively more effective in lean mixes than in rich ones. Compressive strength of CSF concrete increased with increasing CSF percentages for both normal and superplasticized mixes up to an optimum levels of 10-15% and 15-20%, respectively. The amount of OPC (kg/m`3) necessary to bring a change in compressive strength of 1MPa was also determined and the theoritical blend proportions of OPC-CSF necessary to produce 28-day compressive strength equivalent to the plain OPC mixes were determined from the produced data above. The theoretical blend proportions were examined experimentally and the data were used to establish the relationship between strength and water/cementitious ratio for the blend mixes with and, without superplasticizer. Results showed that this basic relationship had changed quantitatively but not qualitatively when CSF was used. A cost study using current OPC and CSF material costs -was performed in an attempt to determine'the- most economic blend proportions. A total of eleven different concrete -mixes were selected to study the effect of curing environment (hot and temperate), initial curing time (0,1,3 and`-7 days) and curing method (water and polythene sheeting) on the compressive strength, permeability and absorption properties of the CSF concretes. Tests were carried out at 3,7, '14, 28,56,90 and 180 days of age. In addition five different mortar, mixes were used to examine the effect of curing environment (temperate and hot) an the *permeability, pore size distribution and durability to magnesium sulphate attack. Test results showed that hot Iraqi curing environment was favourable to the early-age strength, absorption and permeability of plain OPC mixes. However, - the later-age properties were significantly lower than those obtained for concretes cured in a temperate UK environment. For plain OPC mixes a critical curing period of 3 days was found under both temperate and hot environment. For the CSF blend mixes critical curing periods for the temperate and hot environment were found to be 3 and 1 day respectively. Results also reveal the importance of curing specimens immediately after casting for one day. Research work has also confirmed the superiority of water curing over polythene sheeting in a temperate environment for the rich plain OPC and CSF mixes. However, there was no significant difference between water and polythene for lean mixes. The reduction in , permeability and absorption properties of CSF mixes cured in a both temperate and hot environments is thought to be due to the changes in the pore structure brought about by the use of silica fume. Combining CSF with OPC was found to increase the percentages and volume of fine pores at the expense-of coarse pores. This effect may be described as a "refining" effect. Finally, the performance of CSF mortar mixes cured in a temperate and hot environment and their resistance to magnesium sulphate attack was significantly better than the plain OPC ones.
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Heap, Jennifer Anne. "Studies of toxic fume emissions from burning textiles." Thesis, University of Salford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358765.
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Ferreira, Miriska. "Exposure of welders to manganese in welding fumes / Miriska Ferreira." Thesis, North-West University, 2012. http://hdl.handle.net/10394/8694.
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Aims and objectives: The general aim of this study was to determine the personal respiratory exposure and biological monitoring of manganese (Mn) present in welding fumes as well as its neurological influence on welders. The objectives of this study were: (i) to assess the respiratory exposure of welders to Mn present in welding fumes; (ii) to assess the biological Mn load of welders via the use of nail clippings; (iii) to establish possible correlations between respiratory exposure to Mn and its presence in nail clippings, and (iv) to determine the possible difference in finger dexterity and coordination between Mn exposed welders and a control group.
Methods: A gravimetrical method was used to determine the respiratory exposure of welders. A cassette containing a 0.8-μm, cellulose ester membrane filter, attached to the side of a welding helmet provided, was connected via a stainless steel fitting to the inside (respiratory zone) of the helmet. Chemical analysis (metal content) of the welding fumes was done according to the NIOSH 7300 method, using Inductively Coupled Argon Plasma, Atomic Emission Spectroscopy (ICP-AES). Nail clippings were collected at the beginning and end of the study to determine the Mn level in the nails in both welders as well as paired controls. The nails were deposited into small, plastic vials and also analysed according to the NIOSH 7300 method. A Perdue pegboard and mirror drawing test was also conducted to determine the influence of Mn exposure on finger dexterity and hand-eye coordination of welders.
Results: Mn exposure in the welding fumes did not exceed the occupational exposure limit – recommended limit (OEL-RL) (1 mg/m3) of the Regulations for Hazardous Chemical Substances (RHCS), although two of these exposures exceeded the action level (0.5 mg/m3). No statistical significant correlations were found between the Mn respiratory exposure and the Mn found in the nails of the welders. Mn in the nails of exposed welders was statistical significantly higher (p = 0.003) than that of controls. The only statistical significant differences found in the motor function tests between the controls and welders were the test which was done by using their non-dominant hand in the beginning of the study (p = 0.016) and when the non-dominant hand values were pooled (p = 0.012). The usage of both hands
simultaneously showed results that leaned toward statistical significant decrease of the welders compared to the control subjects (p = 0.090). In all these cases the controls inserted more pins than the welders. Only one moderately positive correlation (r = 0.612; p = 0.02) was found between Mn in the welding fumes and the number of errors made in the mirror drawing coordination test done by the welders.
Discussion and Conclusions: The Mn in the nails of the control group was significantly lower than the Mn in the nails of the welders. This indicates that Mn respiratory exposure may influence Mn body burden although no correlation between Mn in welding fumes and Mn in nails were found. Nail Mn may serve as a biomarker to determine Mn body burden. Only the use of the non-dominant hand of the control subjects compared to the welders showed a significant decrease in finger dexterity of the welders. The moderately positive association between the Mn in the welding fumes and the number of errors made in the mirror drawing coordination test done by the welders indicates that with an increase in Mn in welding fumes, a decrease in hand-eye coordination will occur. It can be concluded that welders’ finger dexterity and hand-eye coordination may be influenced by the exposure to Mn in the welding fumes.Thesis (MSc (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2013
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Correa, Priscila Gomes. "História, política e revolução em Eric Hobsbawm e François Furet." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/8/8138/tde-06072007-120331/.
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Nesta dissertação pretendemos realizar um estudo comparativo entre Eric Hobsbawm e François Furet, dois importantes historiadores do século XX, com trajetórias intelectuais opostas que, no entanto, convergiram para a interpretação das relações entre história, política e revolução. Tomamos como fonte documental seus trabalhos historiográficos, com o intuito de refletir sobre a relação entre o pensamento histórico e o pensamento político. Assim, situando o problema da relação entre o intelectual e a política, buscamos, por meio da análise historiográfica e do exercício sistemático de comparação e confrontação, abordar os participantes do debate historiográfico/político como atores históricos, visto que atuando em uma diversidade de culturas políticas e tradições de pensamento.Our goal in this dissertation is to compare the works of two twentieth century historians - Eric Hobsbawm and François Furet - analysing their different intellectual trajectories and their interpretation of the relationship between history, politics and revolution. The documentary source used in this study consists mainly of their historiographical works. In this way, by an historiographical analysis and by a systematic comparation and confrontation of their works, we have approached the debate that results from the different and contrasting political culture and ideological thought present in both as historical actors.
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Rubin, Edward A. "Gas, Weed, and Fumes| Three Essays in Empirical Environmental Economics." Thesis, University of California, Berkeley, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10928207.
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This dissertation presents a three-part study in modern empirical environmental economics. In these three studies, I focus on five core economic issues—equity, incentives, environmental quality, consumer behavior, and causality—and ask what environmental economics can teach us about three common topics: energy consumption, cannabis legalization, and pesticide application.
The first chapter examines how residential natural gas consumers respond to changes in the price of natural gas. With 70 million consumers, residential natural gas has grown to a first-order policy issue. This first chapter provides the first causally identified, microdata-based estimates of residential natural-gas demand elasticities using a panel of 300 million bills in California. To overcome multiple sources of endogeneity, we employ a two-pronged strategy: we interact (1) a spatial discontinuity along the service areas of two major natural-gas utilities with (2) an instrumental-variables strategy using the utilities' differing rules/behaviors for internalizing upstream spot-market prices. We then demonstrate substantial seasonal and income-based heterogeneities underly this elasticity. These heterogeneities suggest unexplored policies that are potentially efficiency-enhancing and pro-poor.
The second chapter explores what may be unintended—or unconsidered—results of cannabis legalization. Cannabis legalization advocates often argue that cannabis legalization offers the potential to reduce the private and social costs related to criminalization and incarceration—particularly for marginalized populations. While this assertion is theoretically plausible, it boils down to an empirically testable hypothesis that remains untested: does legalizing a previously illegal substance (cannabis) reduce arrests, citations, and general law-enforcement contact? The second chapter of this dissertation provides the first causal evidence that cannabis legalization need not necessarily reduce criminalization—and under the right circumstances, may in fact increase police incidents/arrests for both cannabis products and non-cannabis drugs. First, I present a theoretical model of police effort and drug consumption that demonstrates the importance of substitution and incentives for this hypothesis. I then empirically show that before legalization, drug-incident trends in Denver, Colorado matched trends in many other US cities. However, following cannabis legalization in Colorado, drug incidents spike sharply in Denver, while trends in comparison cities (unaffected by Colorado's legalization) remain stable. This spike in drug-related police incidents occurs both for cannabis and non-cannabis drugs. Synthetic-control and difference-in-differences empirical designs corroborate the size and significance of this empirical observation, estimating that Colorado's legalization of recreational cannabis nearly doubled police-involved drug incidents in Denver. This chapter's results present important lessons for evaluating the effects and equity of policies ranging legalization to criminal prosecution to policing.
Finally, the third chapter investigates the roles pesticides play in local air quality. Many policymakers, public-health advocates, and citizen groups question whether current pesticide regulations properly equate the marginal social costs of pesticide applications to their marginal social benefits—with particular concern for negative health effects stemming from pesticide exposure. Additionally, recent research and policies in public health, epidemiology, and economics emphasize how fine particulate matter (PM2.5) concentrations harm humans through increased mortality, morbidity, mental health issues, and a host of socioeconomic outcomes. This chapter presents the first empirical evidence that aerially applied pesticides increase local PM2.5 concentrations. To causally estimate this effect, I combine the universe of aerial pesticide applications in the five southern counties of California's San Joaquin Valley (1.8M reports) with the U.S. EPA's PM2.5 monitoring network—exploiting spatiotemporal variation in aerial pesticide applications and variation in local wind patterns. I find significant evidence that (upwind) aerial pesticide applications within 1.5km increase local PM2.5 concentrations. The magnitudes of the point estimates suggest that the top decile of aerial applications may sufficiently increase local PM2.5 to warrant concern for human health.
Jointly, the three parts of this dissertation aim to carefully administer causally minded econometrics, in conjunction with environmental economic theory, to answer unresolved, policy-relevant questions.
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Wang, Hong. "Study of Chinese household cooking practices : energy and cooking fumes." Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/43499/.
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First, this research has attempted to identify the underlying reasons for high Chinese family cooking energy consumption. Second, this research has tried to identify ways of reducing Chinese kitchen cooking fume pollution. The literature review indicated that, although cooking energy takes one of the largest proportions of residential building energy consumption, previous studies in this area have not been enough. The published knowledge found indicates that urban residential buildings takes 1/4 of the national building energy consumption (excluding heating). This portion has grown continuously since 2001 in terms of energy consumption intensity (kgce/m2). Among household energy (excluding heating), cooking, home appliances and lighting are the three largest energy end users. Although the increase in cooking energy is low, partially attributed to wide adaptation to gas cooking fuel instead of coal fuel in China, it still takes the largest household energy consumption: 31% in 2011. Many research papers report different results based on field measurements of household energy end users, some of which show conflicting results. However, the literature review has confirmed that in China cooking energy consumes the second-largest amount of household energy after space heating. The literature review also pointed out that, although compared with Western counterparts, Chinese residential buildings consume less national energy, cooking takes a large percentage of household energy. A further literature review showed little valuable information underpinning the reasons for high cooking energy use in Chinese households. Some overseas research papers give hints regarding cooking energy and cooking techniques, cookware, and occupant behaviour. However, the difference in food culture traditions has led to a greater difference between Western and Chinese cooking techniques. Compared with Western countries, Chinese hot dishes require a greater number of cooking techniques. In order to find out more details of cooking energy and fume generation in real Chinese home kitchen conditions, the author used a series of research methodologies to measure and test home energy and cooking fume concentration. The results reconfirm that cooking energy is the second-largest home energy end user after space heating, along with other findings. These other findings include: • The four largest energy end users in northern Chinese households are space heating, cooking, hot water and entertainment. • Hot water, lighting and entertainment energy consumption have clear seasonal characteristics i.e., daily consumption is low in summer and high in winter. This is because of the colder weather in winter (demanding more energy to heat water) and longer nights in winter (with a longer indoor entertainment time and a greater requirement for lighting in the evening). • Daily cooking energy consumption in a given family is almost fixed, although the difference between different families is large. This could lead to further study on the underlying reasons for the difference between families. The most important finding in the research is the discovery of the relationship between home cooking energy and family life cycle. A strong relation was observed between these two factors. This was confirmed by the measurement of the test families as well as the survey of 70 random selected families. The relation is, therefore, denoted as the CookEUI (cooking energy use intensity) of the different family life cycles. Following the data analysis and survey, it was also found that the cooking energy for a certain family life cycle was constant, i.e., locked in an FLC stage until the stage changed. Finally, a database was built into the IES energy simulation using figures found in the research. This represents significant progress in home energy study. Before discovering cooking EUI, cooking energy in most pieces of energy simulation software was treated as a process load with a constant figure. A literature review of a large number of research papers concluded that cooking fumes have an adverse impact on people’s health. In China, a typical housewife spends about 4 hours in the kitchen every day, preparing and cooking meals. A comfortable and healthy cooking environment is critical for cooks’ health. It was also found that COF emissions in Western and Chinese kitchens differed largely in mass concentration. Cooking method, cooking oil and cooking temperature all contribute to the difference. Many other researchers have investigated the details of hood systems and their construction features in order to understand their efficiency in removing cooking fumes. However, most of the research has been based on commercial kitchen application. There is very little research on home kitchen hood efficiency. Research also points out that natural ventilation in the kitchen space has a certain amount of influence on the capture efficiency of an exhaust system. For example, opening the door is more efficient than opening a window. In this research, the measurements of kitchen PM2.5 and PM10 were carried out in real home kitchen cooking conditions. The relation between PM2.5 and PM10 emissions and different Chinese cooking methods was measured. It was found that deep frying and stir frying discharged the most PM2.5, while boiling emitted the least. A typical PM2.5 discharging pattern in Chinese cooking was observed. The pattern showed a sharp increase in PM2.5 concentration in the beginning at breath level with a drop afterwards because of the using up of cooking oil or the rising of water steam to a higher level. A small sub-surge was observed after the first selection because the downward flow of cold air brought high-level PM2.5 down to breath level. A very interesting finding observed when using tracer gas to measure kitchen cooking hood efficiency was the large difference between the airflow rate listed on the kitchen fume hood nameplate and the airflow rate measured in real kitchen conditions. On the nameplate of the cooking hood, airflow was rated as 800 m3/h at medium speed, while in the tracer gas testing the flow rate was a maximum of 175 m3/h when all the kitchen windows and the door were open. This finding reinforces the experiment conclusion by the Lawrence Berkeley National Laboratory for the seven representative devices they tested, whereby, according to Chen (2012), the capture efficiency varied from less than 15% to more than 98%. Identifying the airborne moving characteristics of PM2.5 can be used to help redesign ventilation systems for Chinese home kitchens. The traditional way of enhancing cooking fume removal efficiency is to increase the fan discharge pressure head. This leads to increased energy consumption. It also has less effect on removing PM2.5 particles, since, unlike PM10, PM2.5 is affected by airflow rate more significantly than air velocity. The proposed new ventilation system is intended to treat PM2.5 and PM10 separately. PM10 will be removed by the filter in recirculation devices and PM2.5 will be exhausted by a direct venting fan with replacement air. In this way, less energy is used and the system is more efficient at removing kitchen PM2.5.
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Dudding, Lyndon M. "Determination of platinum in environmental samples by quadrupole inductively coupled plasma mass spectrometry." Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/843538/.
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The increase in environmental levels of platinum can in part be attributed to the introduction of motor vehicle catalytic converters. Quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) has been evaluated as a analytical tool for the determination of platinum in environmental samples, such as vegetation, roadside dust, soil and sediment. Instrumental parameters were studied and a forward power of 1.4 kW and nebuliser flow rate of 0.95 1 min-1 were shown to give the optimum signal response for the 195Pt+ isotope. A detection limit of 0.12 ng ml-1 was achieved. Iridium was shown to be the most suitable choice for use as an internal standard with the 191Ir+ isotope being monitored. Various digestion methods were studied with aqua regia / hydrofluoric acid open vessel digestion being found to give good recovery for 2 certified reference materials, NIST 2556 (Used Autocatalyst, Pellets) and 2557 Used Autocatalyst, Monolith) with concentrations of 681 (38) mug g-1 and 1085 (32) mug g-1 respectively [certified values 697.4 (2.3) mug g-1 and 1131 (11) mug g-1]. Attention has been given to the problem of spectroscopic interference on 195Pt+ from hafnium oxide. Various correction methods were evaluated with a modification proposed to a previous method of mathematical correction being found to provide the best correction for the 179Hf16O+. An 'in-house' reference sample was prepared from a used catalytic converter and its platinum content of 3563 (176) ng g-1 established through inter-laboratory and inter-method procedures. Common rye grass (Lolium perenne) was shown to uptake platinum from both solid and liquid platinum-containing matrices. The methods developed were applied to a study of roadside dust samples taken from a busy section of the London M25 orbital motorway. The measured platinum levels of up to 194 ng g-1 agree with published literature from other European countries and represent a useful contribution to the knowledge concerning roadside platinum in the UK.
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Madden, M. G. "Hexavalent chromium in aerosols evolved during a high temperature metallurgical process." Thesis, University of Bradford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376689.
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Oshodi, R. O. "Cytotoxicity, irritancy and fibrogenicity of industrial metal-fumes in the rat and guinea-pig." Thesis, University of Bradford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378123.
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Pun, Pierre Che Ho. "Influence of silica fume on chloride resistance of concrete." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq28837.pdf.
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Hirst, Adrian Anthony. "Fume formation in flux cored metal inert gas welding." Thesis, University of Bradford, 1990. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306180.
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Kashi, Mohsen Gholam-Reza. "Freeze-thaw durability of high strength silica fume concrete." Diss., Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/53942.
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Specimens from 27 batches of concrete with water to cementitious (cement plus silica fume) ratio of 0.25 to 0.32, with and without entrained air, were tested for freeze-thaw durability in accordance with ASTM C666, procedure A (freezing and thawing in water). In addition, another set of similar specimens were moist cured for 28 days instead of 14 days and tested in accordance with ASTM C666 , Procedure A to determine the effect of curing time on the freeze-thaw durability of high strength concrete. Results show that non air-entrained high strength concrete with water cementitious ratio of less than 0.30, regardless of the length of curing time, is frost resistant. Non-air-entrained concrete with water-cement ratio of 0.32 is also durable if silica fume is not used.Ph. D.
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BAUDET, STEPHANE. "Régulation des activités ioniques intracellulaires dans le myocarde hypertrophié de furet." Poitiers, 1990. http://www.theses.fr/1990POIT2291.
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Une etude comparative du muscle cardiaque temoin et hypertrophie de furet a ete realisee afin de savoir si les perturbations de la contractilite du ventricule droit soumis a une surcharge de pression hemodynamique provenaient d'anomalies de la regulation des activites ioniques intracellulaires (ph, sodium et calcium). Les techniques utilisees ont permis la mesure de la contraction isometrique de muscles intacts (capteurs de microdeplacements), des activites ioniques sarcoplasmiques (microelectrodes selectives), et de la sensibilite au calcium des myofilaments (fibres cardiaques pelees chimiquement). Les resultats ont montre que l'hypertrophie ventriculaire droite s'accompagnait d'une reduction des capacites d'accumulation du calcium par le reticulum sarcoplasmique, liee a une diminution du captage de cet ion et/ou a une augmentation de sa fuite passive. De plus, l'efflux de calcium par le mecanisme d'echange sodium-calcium du sarcolemme est diminue. Les resultats montrent que la stenose pulmonaire induit une plus grande sensibilite au calcium des myofilaments contractiles en presence de cafeine. Par contre, il n'existe pas de difference de l'activite sodique, et du ph intracellulaires entre muscles temoins et hypertrophies au repos. Ces alterations expliquent en partie l'augmentation de l'activite calcique intracellulaire chez les muscles papillaires hypertrophies par rapport aux temoins
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Lobo, Leon M. "Solid phase by-products of laser material processing." Thesis, Loughborough University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.272931.
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Konduru, Sathish Kumar Raju. "Performance evaluations of latex-modified and silica fume modified concrete overlays for bridge decks." Morgantown, W. Va. : [West Virginia University Libraries], 2009. http://hdl.handle.net/10450/10559.
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Thesis (M.S.)--West Virginia University, 2009.Title from document title page. Document formatted into pages; contains xv, 235 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 212-216).
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El-Khatib, Jamal M. "Durability related properties of PFA, slag and silica fume concrete." Thesis, University of Aberdeen, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315418.
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Concrete has the largest production of all man-made materials. Compared with other construction materials, it possesses many advantages including low cost, general availability of raw materials, low energy requirement and utilization under different environmental conditions. Therefore, concrete will continue to be the dominant construction material in the foreseeable future. However, durability of concrete and reinfored concrete structures are still of worldwide concern, so producing a good quality concrete which impedes the ingress of harmful substances into it is of paramount importance. Cement replacement materials have been introduced into concrete mixtures for the purpose of improving the durability performance. Hence, the aim of the present investigation is to study the durability of concrete with and without cement replacement materials under various initial curing conditions. In this thesis various concrete mixes with and without cement replacement materials were considered. The cement replacement materials were, pulverised fuel ash, condensed silica fume, and ground granulated blast furnace slag. Superplasticiser was added to the majority of the mixes considered and air entraining agent to some of the mixes. Various curing regimes were employed which comprised hot dry curing to simulate concrete in the hot arid areas in the world and curing at normal temperature. Curing involved air curing, membrane curing and moist curing for fourteen days followed by air curing. A number of tests were conducted at either one particular age or at various ages. These included tests on porosity and pore structure of pastes obtained by mercury intrusion porosimetry technique, water absorption which covers the water absorption of concrete obtained by shallow immersion and the water absorbed by capillary action when the concrete surface is in contact with water, sulphate resistance of concrete which is performed by immersing the concrete specimens in sulphate solution, and monitoring the change in length at various periods of immersion, chloride penetration profiles of concrete at various ages of exposure. In addition to these tests on durability related properties, tests on compressive strength were also performed. Throughout the study a correlation between pore structure and durability related properties is investigated. A comprehensive compilation of chloride penetration data is made and an empirical expression is derived for the prediction of long term diffusion coefficients. At the end of the investigation, limitations of the present study, conclusions and suggestions for future research are made.
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Tank, Suresh Bhagwanji. "The use of condensed silica fume in Portland cement grouts." Thesis, University College London (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307794.
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Claisse, Peter Arnold. "The properties and performance of high strength silica fume concrete." Thesis, University of Leeds, 1988. http://etheses.whiterose.ac.uk/3256/.
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Silicafume (SF) has been used as a partial replacement for cement in concrete and experiments have been carried out to measure the durability of the mixes. The SF mixes were made with 20% SF replacement of cement and waterlcement (wlc) ratios of 0.3 and 0.46. Three different curing conditions were used to simulate different site conditions and tests were carried out at 3,28 and 90 days after casting. The following properties were measuredfor the two SF mixes and the two control (OPC) mixes for each of the ages and curing conditions: corrosion rate of embedded steel by linear polarisation, electrical resistivity, carbonation depth, water vapour permeability, chloride permeability, oxygen permeability and porosity from helium and mercury intrusion. Samples were also investigated by thermogravimetric analysis. The resulting data matrix was analysed by using the method of analysis of variance to quantify the effect of the SF on the properties tested and their sensitivity to age and curing. It was also analysed by multiple regression to identify major effects of one property on another. It was concluded that SF will reduce the corrosion rate and that the major contributing factor is the substantial increase in resistivity that the SF causes. This increase in resistivity was found to be highly sensitive to cold curing in the short term but this effect was not permanent. The cause of the increase in resistivity is believed to be the depletion of calcium hydroxide which is caused by the pozzolanic activity of the SF. The analysis also indicated that the SF reduces the porosity in the .01-.15)1m size range and that this has a major influence on the durability.
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Mortazavi, Seyed Bagher. "Inter-relationship between ultraviolet, ozone and hexavalent chromium in metal inert gas (MIG) welding process." Thesis, University of Bradford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324614.
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Welding is a common metal fabrication process within industry. Epidemiology suggests that welders as an occupational group demonstrate slight, but significant, increased risks of respiratory ill-health. This might be expected as welding processes often present high levels of occupational exposure to oxidising gasses and weld fumes which are often inadequately controlled through local exhaust ventilation or personal respiratory protection because of high costs and the burden of worker participation. Fundamental control strategies of occupational hygiene encourage development and use of engineering controls as the best means to optimally control occupational exposure. However, engineering controls have not yet been successfully developed to control occupational exposure to welding fume and gases. This thesis investigates the interrelationships between ultra-violet radiation (UV). ozone (0:;). and hexavalent chromium (CrVI) in metal inert gas (MIG) welding in order to investigate possible methods to control occupational exposure to welding fume and gases by engineering contro!' Past studies of occupational ill-health in welders are reviewed as is the currently understanding of the physico-chemical principles by which the various components of welding fume evolves. Experiments were designed to investigate the mechanisms of formation of UV, 0 3 and CrVI formation from which a number of possible control strategies were developed further. Among these results emerge two process modifications with exciting potential to reduce two toxic components. 0, and CrVI , in stainless steel welding fume and gas. The addition of trace amounts of Zinc to chromium containing steel wires virtually eliminates all 0, and significantly reduces hexavalent chromium within the weld plume. As Zn is a volatile metal, it does not contaminate weld quality but increases the zinc oxide le\els in the fume slightly. A second method developed in this thesis involves the addition of a dual shield gas shroud containing reducing gases such as C2H .. to remove 0, and consequently. reduce Cr(VI) levels. Preliminary results suggest that these methods can be used separately. or in combination, to provide a practical means of controlling occupational exposure to two of the more toxic components of welding fume and gases. This thesis describes in details the experiments and results culminating in successful preliminary development of engineering controls for 0 3 and CrVI through process modification of the stainless steel MIG welding process. Further work for further development of these methods is outlined and funding to extend this area of applied research is being actively pursued with the support of major UK industry.
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Palmer, Benjamin L. "Effect of welder group size on individual respiratory exposures to welding fumes." Oklahoma City : [s.n.], 2010.
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Collet, Jean-Paul. "Exposition à la fumee de cigarette et incidence de l'otite chez l'enfant." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63960.
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El-Gamal, Fathi Mahmoud Hussein. "Welding fumes as a cause of impaired lung function in shipyard workers." Thesis, University of Newcastle Upon Tyne, 1986. http://hdl.handle.net/10443/1575.
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Welders and caulker/burners are usually exposed to heavy clouds of fumes. These fumes contain some gases and particulates which are potentially harmful. There have been several surveys of the health of welders since 1936. These studies demonstrated an association between exposure to fumes and respiratory symptoms. However, no long term effect of fumes on respiratory function has been established. The gases and particulates in the fumes from welding and caulking/burning are very small in size and on this account are capable of reaching the small airways in the periphery of the lung. If welding fumes are harmful to the lung small airway dysfunction should be present in the younger workers. In view of this, in the present study relatively young men were examined and tests specific to small airway function were used. The subjects for this study were male Caucasian workers aged 18 - 47 years, mean age 31.5 years. The target sample comprised 181 welders and 151 caulker/burners and the control sample comprised 181 other tradesmen. The two samples were selected from the same yard. Anthropometry, respiratory symptom and occupational questionnaires, cough frequency questions, forced spirometry, single breath nitrogen test, transfer factor, and an exercise test were performed. The results were submitted to multiple regression analysis. The target workers were compared with the control subjects. Comparisons were also made within the groups of welders and caulker/burners separately. A subsample of the whole selected subjects (age 20 - 25 years) was examined separately to investigate the early effects of fumes on the lung of exposed young workers. In the whole population, compared with the controls, the welders and caulker/burners were found to have significantly higher prevalence of wheeze symptom, and fume exposure interacted with age to increase breathlessness on exertion in the older subjects. In the very young workers (age 20- 25 years) chronic cough and phlegm (chronic bronchitis, MRC) was significantly higher among the target workers compared with the controls. In the group of welders smoking interacted with fumes to increase wheeze in the workers who smoked while increased fume exposure in the older subjects was associated with increased breathlessness on exertion. In the whole population the mean values of closing volume (CV%) and closing capacity (CC%) were significantly higher in the target workers compared with the controls. This effect was independent of age and smoking which were also important. In the subsample of the very young workers similar effects were found, and in addition the mean value of the residual volume (RV%) in the target group was significantly higher than that in the control group. In the whole population fume exposure enhanced the deterioration with age in forced expiratory volume (FEV1) and forced vital capacity (FVC) significantly more in the target workers than in the control subjects. These indices were not affected by exposure in the very young workers. Amongst the group of welders, increased levels of exposure to fumes (duration and intensity) enhanced the deterioration with age in CV%, CC%, breathlessness on exertion and Tlco. High exposure was also associated with decreased Kco in the workers who smoked. Amongst the caulker/burners, increased levels of exposure to fumes enhanced the deterioration with age in CV%, CC%, slope of phase III (SLIII), nitrogen difference index (N2 Diff) and RV%. The findings of the present study are evidence that high levels of fumes from welding and burning or other factors related to these trades, cause long term impairment of lung function of shipyard welders and caulker/burners.
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Do, Emmanuelle. "PH intracellulaire et sensibilité à l'hypoxie du muscle cardiaque hypertrophié de furet." Poitiers, 1994. http://www.theses.fr/1994POIT2297.
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Une etude comparative des effets de l'hypoxie sur l'activite contractile (capteur de micro-deplacements), ph intracellulaire (phi) (microelectrodes sensibles) et les concentrations intracellulaires en magnesium (mg#2#+i) et calcium (ca#2#+i) (indicateurs fluorescents) a ete realisee chez le furet, dans des preparations de cur temoin et hypertrophie par stenose de l'artere pulmonaire (hypertrophie ventriculaire droite par surcharge de pression). Le phi des muscles papillaires de cur temoin et hypertrophie est similaire. Le pouvoir tampon, evalue en fonction du phi, et l'activite de l'echange membranaire na/h ne sont pas modifies dans les preparations hypertrophiees. La sensibilite de la force contractile a des changements de phi est aussi similaire dans les 2 groupes de muscles. Lors d'episodes hypoxiques successifs en absence de glucose dans le milieu de perfusion, les variations de l'amplitude de la tension developpee suite a une stimulation electrique, sont moins marquees dans les muscles hypertrophies que dans les muscles temoins. Ces differences pourraient en partie resulter de variations de phi pendant l'hypoxie, differentes dans les muscles hypertrophies. A 22c, l'alcalinisation en debut d'hypoxie et l'acidification au retour en milieu oxygene sont effectivement reduites dans les muscles hypertrophies. A 35c, en plus des modifications precedentes, l'acidose hypoxique est accentuee dans les preparations hypertrophiees. Mg#2#+i et ca#2#+i sont significativement plus elevees dans les cellules hypertrophiees (myocytes isolees). L'augmentation de mg#2#+i mesuree lors du blocage de la glycolyse et des phosphorylations oxydatives par le deoxyglucose est similaire dans les cellules controles et hypertrophiees. L'ensemble de ces resultats suggere des modifications des mecanismes de consommation et de production de protons pendant l'hypoxie dans les muscles hypertrophies par comparaison aux muscles temoins. Il pourrait s'agir d'une diminution du metabolisme de la phosphocreatine et d'une acceleration de la glycolyse anaerobie
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Nicholson, Graham Philip. "Studies on the performance of open fronted and 'ultra-clean' ventilation systems." Thesis, King's College London (University of London), 1997. https://kclpure.kcl.ac.uk/portal/en/theses/studies-on-the-performance-of-open-fronted-and-ultraclean-ventilation-systems(fce02f06-c29c-4730-88d1-317e078276d9).html.
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DESHINI, AMARENDRANATH. "FINENESS OF DENSIFIED MICROSILICA AND DISPERSION IN CONCRETE MIXES." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1186774530.
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Cruz, Jimenez Juan Carlos. "Hydrolases on fumed silica : conformational stability studies to enable biocatalysis in organic solvents." Diss., Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/3648.
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姜泰安. "Mutagenicity and carcinogens of cooking oil fumes and evaluation of preventive effect of fume extractor and natural antioxidants." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/47345841657914368347.
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Wu, She-Ching, and 吳思敬. "The Safety of Peanut Oil Fumes and the Reduction of Fumes Formation." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/78956537909316768649.
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博士國立中興大學
食品科學系
90
The aim of this study is to investigate the safety of oil fume produced from peanut oil heated to its smoke point. The mutagenicity, genotoxicity and possible mechanisms of the oil fume were evaluated, and mutagens present in oil fumes were identified. The peanut oil was then refined and treated with addition of antioxidants in order to reduce the mutagenicity of the oil fumes from heated oil. The first part of this study focuses on investigation of the Seven commercial edible oils including soybean oil, corn germ oil, sunflower oil, peanut oil, blend peanut oil, calola oil and lard were investigated for their physical and chemical properties as well as for the mutagenicity of oil fumes by applying the Ames test. The smoke points of those oils were 118, 119, 95, 98, 107, 138 and 137 oC, respectively. Lard had the best oxidative stability among those seven oils as determined by the Rancimat method. Peanut oil produced the largest amount of fume. The oil fumes of these edible oils showed various degrees of mutagenicity toward Salmonella typhimurium TA98 and TA100 (p<0.05). According to the undesirable fumes formation of peanut oil at relatively low temperature, which is the major edible oilproduced in Taiwan. The mutagenicity of fumes obtained from heating peanut oil was studied and the mutagenic compounds was identified. The result revealed that the peanut prepared from roasted peanut kernel (ROPO) showed a lower smoke point, less unsaturated fatty acids, more fume formation and stronger mutagenicity than that from unroasted kernel (UROPO). Further investigation of mutagenic compounds was performed by the Ames test and GC/MS analysis. Amoung the twelve compounds identified from the neutral fraction of methanol extract four compounds at a dose of 10 g per plate were mutagenic to Salmonella TA98 and TA100 cells in the order trans-trans-2,4-decadienal (t-t-2,4-DDE) >trans-trans- 2,4-nonadienal (t-t-2,4-NDE) >trans-2-decenal (t-2-DCA) >trans-2-undecenal (t-2-UDA). Results report the enal compounds formed as the mutagens in the fumes of peanut oil and indicate that inhaling cooking fumes might cause carcinogenic risk. The cytotoxicity of peanut oil fumes (POF) and their genotoxicity using single-cell electrophoresis (comet assay), and their induction of reactive oxygen species (ROS) in human A-549 cells were investigated. POF was found to show cytotoxicity to A-549 cells and DNA damage. The glutathione (GSH) content in cell and the activity of GSH antioxidative enzymes were reduced. t-t-2,4-DDE at 37 oC could produce superoxide anion, hydrogen peroxide, and hydroxyl radicals in phosphate buffer (pH 7.4), and form intracellular reactive oxygen species (ROS) in A-549 cells which was determined by dichlorofluorescein assay. Moreover, t-t-2,4-DDE caused a significant (p<0.05) oxidative damage of 8-hydroxy-2’ deoxyguanosine (8-OHdG)to 2’-deoxyguanosine in A-549 cells. While increasing damage of t-t-2,4-DDE and reaction time, the results demonstrated that the DNA damage in A-549 cells induced by t-t-2,4-DDE was related to the formation of ROS. The influence of degumming treatment of peanut oil on the contents of mutagenic compounds in fumes from heated peanut oil was investigated. The results indicated that the peanut oil prepared from roasted peanut kernels underwent degumming treatment had lower free fatty acid (FFA) content and higher smoke point, was more clear in color, and produced less fumes when heated at smoke point. Moreover, when compared to untreated peanut oil, the mutagenicity of oil fumes of degummed peanut oil toward Salmonella typhimurium TA98 and TA100 was reduced to 81 and 73% (p<0.05), respectively. The degummed peanut oil which was obtained by adding 3% water and heating at 60℃ for 20 min produced the least amount of mutagenic fume. The contents of four mutagenic compounds, t-t-2,4-DDE, t-t-2,4-NDE, t-2-DCA,and t-2-UDA in oil fumes of degummed peanut oils were drastically decreased (p<0.05), especially the t-t-2,4-DDE. The results also indicated that FFA content had a high linear correlation with mutagenicity (r2 = 0.9978) and content of t-t-2,4-DDE (r2 = 0.7685). Moreover, there was a correlation (r2 = 0.7816) between the content and the mutagenicity of t-t-2,4-DDE. The decrease of FFA by degumming might explain the reduction of mutagenic alkenal compounds and mutagenicity of fumes from heated peanut oil. The preventive effects of various antioxidants on the mutagenicity and the formation of enal mutagenic compounds in degummed peanut oil (DPO) fumes were investigated. The mutagenicity of the DPO fumes was significantly reduced (p< 0.05) by various antioxidants added before heating. The addition of antioxidants increase the smoke point and oxidative stability of DPO, and decreased the yield of oil fumes and the amount of mutagens. Synthetic antioxidants including butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tertiary butylhydroquinone (TBHQ) were more effective in reducing the mutagenicity and the amount of four enal compounds in fumes from DPO than natural antioxidants such as -tocopherol, catechin, and rosemary extracts. Adding appropriate antioxidants not only reduced the mutagens but also improved the physical and chemical properties of DPO. The results obtained in this study might be useful for developing edible cooking oils with high smoke point, lesser fume, and lower mutagenicity with the addition of antioxidants. In this study, the oil fumes from heated oil were found to be mutagenic and genotoxicity. After fractionation, 4 mutagens including t-t-2,4-DDE, t-t-2,4-NDE, t-2-DCA and t-2-UDA were identified. The ROS present in oil fumes could lead to the cleavage of DNA as well as the mutations of base pairs in the DNA. It was found that both the degumming process and the addition of antioxidants could generally improve the physico-chemical properties of peanut oil, reduce the content of all four mutagens present in the oil fumes, and therefore decrease the potential health hazards to household women exposed to the oil fumes.
47
Jacobs, Peter John. "Laboratory fume hood performance." Thesis, 2009. http://hdl.handle.net/10539/5966.
Full textAbstract:
ABSTRACT
Introduction
Laboratory fume hoods are mechanical devices used to extract harmful vapours from
indoor workplaces in order to prevent human exposure thereto. Laboratory fume hoods
are considered an engineering control in the hierarchy of control and are ubiquitous in the
modern laboratory. Protection offered by the fume hood depends on whether it is
performing according to its original design. This performance needs to be maintained for
as long as the fume hood is in use. Gaining a better understanding of this performance
and the limitations of the fume hood are essential in ensuring constant operator
protection.
No performance or measurement standard to which fume hoods need to comply exists in
South Africa. The Occupational Health and Safety Act, 1993 (Act no. 85 of 1993)
requires engineering controls to be evaluated every 24 months. The Act does not stipulate
how such evaluations need to be conducted.
The Forensic Science Laboratory (FSL) of the South African Police Service has 49 fume
hoods installed in its facility in Silverton, Pretoria. The FSL set a performance standard
for its fume hoods at 0.51 m.s-1 ± 20% average across the face of the fume hood. The FSL
selected the ANSI/ASHRAE 110 test method to evaluate the performance of its fume
hoods against this standard.
v
Objectives
The first objective of the study was to measure face velocities of fume hoods as installed
in a forensic science laboratory and calculate the averages, and to determine whether
these comply with the set standard.
The second objective was to measure face velocities of fume hoods as installed in a
forensic science laboratory and calculate the average in order to determine their
performance over time.
The third study objective was to observe laboratory fume hoods as installed in a forensic
science laboratory to see whether fans were operational each month for 11 months (i.e.
down time).
Methods
10 Observations and 10 tests were carried out on each fume hood. Observations related to
whether fume hood fans were functioning or not. Testing was a measure of performance
and required the actual measurement of face velocities. A calibrated thermal anemometer
was used to take velocity measurements. Measurements taken represent standard
velocities. Fume hood faces were divided into imaginary grids not exceeding 30 cm x 30
cm. Velocity measurements were taken at the centre points of these grids. The arithmetic
means were calculated for these measurements. The mean of the test means was then
vi
calculated for every fume hood. This, so that a comparison could be made between the
mean and the set standard.
Observations indicated that at the onset of the study 14% of fume hoods were not
operational. By the end of the study 27% were not operational. A decline of 13% over the
study period. At one point during the study 47% of the fume hoods were not functioning.
Results
82% of the fume hood population performed outside the standard. 12% underperformed
at less than 0.41 m.s-1 while 70% overperformed at velocities exceeding 0.61 m.s-1.
ANOVA and regression analyses revealed that performance of the fume hoods over time
remained fairly constant (e.g. regression analyses p-value = 0.8538).
Discussion and conclusion
Fume hood operability and performance results indicate the need for urgent investigation
into the correct use of this resource within the FSL. Results are less than satisfactory with
the health of laboratory personnel being potentially compromised. Comprehensive
procurement, installation, operating and testing procedures need to be compiled, or if
available, reviewed and implemented. Further study into the performance of the fume
hoods may also be necessary using additional performance indicators.
48
姚永康. "Numerical simulation of fume hood." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/15540323080549250238.
Full text
49
Smith, William E. "Gelation kinetics of fumed silica-alcohol suspensions /." 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3242997.
Full textAbstract:
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2006.Source: Dissertation Abstracts International, Volume: 67-11, Section: B, page: 6576. Adviser: Charles F. Zukoski. Includes bibliographical references (leaves 68-71) Available on microfilm from Pro Quest Information and Learning.
50
張銀濃. "An investigation into the effect of silica fume adding procedure on the physical properties of silica-fume concrete." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/92655296218264134093.
Full textAbstract:
碩士建國科技大學
土木與防災研究所
98
Proper introduction of silica fume in concrete can improve both the mechanical and durability characteristics of concrete had been proved in many reports. Since the silica fume has high hydrophilicity and will become very sticky after it gets wet, it is difficult to add the silica fume with pipeline through air pressure transports. Generally, an artificial broken bag method is employeed. The dry silica fume is measured and then threw into the concrete directly. However, this method has the shortage of low efficiency, high pollution, and artificial measurement error, which becomes a barrier against proper utilization of silica fume concrete. Silica fume can induce pozzolanic reaction only under the stimulation of the calcium hydroxide produced in the hydration of portland cement and some other chemical compound. It will not have any hydration with water. Therefore the mixing silica fume with water will not affect the chemical reaction between silica fume and concrete. This research try to use wast water recovery equipment in Ready-Mixed Concrete Plant to make liquefied silica fume first, and then pumped it into concrete mixer to produce silica-fume concrete. A series of tests show that better performance can be obtained both in workability of fresh concrete and the hardened properties when using liquefied silica fume to produce silica-fume concrete rather than using dry silica fume. In addition, actual practice had shown that about 25% of the productivity of silica-fume concrete can be increased after adopting the liquified procedure. Thus the liquefied procedure is worthwhile to promote in the industry. Key words：liquified silica fume, silica-fume concrete