Investigation of Materials for the Reduction and Prevention of Corrosion on Highway Maintenance Equipment, TR-472, 2009

The issue of corrosion of winter maintenance equipment is becoming of greater concern because of the increased use of liquid solutions of ice control chemicals, as opposed to their application in solid form. Being in liquid form, the ice control chemicals can more easily penetrate into the nooks and crannies on equipment and avoid being cleansed from the vehicle. Given this enhanced corrosive ability, methods must be found to minimize corrosion. The methods may include coatings, additives, cleansing techniques, other methods, and may also include doing nothing, and accepting a reduced equipment lifetime as a valid (perhaps) trade off with the enhanced benefits of using liquid ice control chemicals. In reality, some combination of these methods may prove to be optimal. Whatever solutions are selected, they must be relatively cheap and durable. The latter point is critical because of the environment in which maintenance trucks operate, in which scrapes, scratches and dents are facts of life. Protection methods that are not robust simply will not work. The purpose of this study is to determine how corrosion occurs on maintenance trucks, to find methods that would minimize the major corrosion mechanisms, and to

The early IL-4 response to Leishmania major responsible for progressive disease in BALB/c mice is subject to the control of autocrine IL-2 production and regulatory CD4+C25+ T cells

Résumé : La majorité des souches de souris de laboratoire sont résistantes à l'infection par le parasite Leishmania major (L. major). A l'opposé, les souris de la souche BALB développent une maladie évolutive. La résistance et la sensibilité sont corrélées avec l'apparition de lymphocytes T CD4+ spécifiques du parasite, Th1 (de l'anglais T helper) ou Th2 respectivement. La réponse aberrante Th2 chez les souris de la souche BALB/c dépend, au moins en partie, de façon critique de la production rapide d'IL-4 suite à l'infection. Ce pic précoce d'IL-4 est produit par une population de lymphocytes T CD4+ restreinte aux molécules du MHC de classe II, exprimant les chaînes du récepteur des cellules T Vß4-Va8. Ces lymphocytes sont spécifiques d'un épitope de l'homologue Leishmania de la molécule RACK1 des mammifères, appelée LACK. Il a été clairement démontré que l'IL-4 rapidement produite par ces cellules T CD4+ Vß4-Va8 induit la maturation Th2 responsable de la sensibilité vis-à-vis de L. major. Des expériences ont été entreprises pour étudier la régulation de cette réponse précoce d'IL-4. Dans ce travail, nous avons documenté, dans les cellules provenant des ganglions de souris sensibles infectées par L. major, une augmentation de la transcription de l'ARNm de l'IL-2 qui précède la réponse précoce d'IL-4. La neutralisation de l'IL-2 durant les premiers jours d'infection induit la maturation des cellules Thl et la résistance vis-à-vis de L. major. Ces effets de l'anticorps anti-IL-2 neutralisant sont liés à sa capacité d'interférer avec la transcription rapide d'IL-4 des cellules CD4+ réactives à l'antigène LACK. Une augmentation similaire d'IL-2 survient chez les souris résistantes C57BL/6 qui sont incapables de générer la réponse précoce d'IL-4. Cependant, la protéiné LACK induit une transcription précoce d'IL-2 uniquement chez les souris sensibles. Des expériences de reconstitution utilisant des souris C.B.-17 SCID et des cellules T CD4+ réactives à LACK provenant de souris BALB/c IL-2-~démontrent un mode d'action autocrine de l'IL-2 sur la régulation de la réponse précoce d'IL4. Par conséquent, chez les souris C57BL/6, l'absence du pic précoce d'ARNm de l'IL-4 important pour la progression de la maladie paraît liée à l'incapacité des cellules T CD4+ réactives à LACK de produire de l'IL-2. Un rôle dans le contrôle de la production précoce d'IL-4 par les cellules T régulatrices CD4+CD25+ a été investigué en déplétant in vivo cette population de cellules. La déplétion induit une élévation du pic précoce de l'ARNm de l'IL-4 dans les ganglions drainant de souris BALB/c, ainsi qu'une exacerbation du cours de la maladie avec des taux augmentés d'IL-4 dans les ganglions. La réponse rapide d'IL-2 vis-à-vis de L. major est aussi significativement augmentée chez les souris BALB/c déplétées en cellules CD4+CD25+. De plus, nous avons démontré que le transfert de 10puissance(7) cellules provenant de la rate de souris BALB/c déplétées en cellules T régulatrices CD4+CD25+ rend les souris SCID sensibles à l'infection et permet la différentiation Th2. Au contraire, les souris SCID reconstituées avec 10' cellules de la rate de souris BALB/c contrôle sont résistantes à infection par L. major et développent une réponse Thl. Chez les souris SCID reconstituées avec des cellules de rate déplétées en cellules exprimant le marqueur CD25, le traitement avec un anticorps neutralisant l'IL-4 au moment de l'infection par L. major prévient le développement de la réponse Th2 et rend ces souris résistantes à l'infection. Ces résultats démontrent que les cellules T régulatrices CD4+CD25+ jouent un rôle dans la régulation du pic précoce d'IL-4 responsable du développement cellulaire Th2 dans ce modèle d'infection. Summary Mice from most strains are resistant to infection with Leishmania major (L. major). In contrast, BALB mice develop progressive disease. Resistance and susceptibility result from parasite-specific CD4+ Thl or Th2 cells, respectively. The aberrant Th2 response in BALB/c mice depends, at least in part, upon the production of IL-4 early after infection. The CD4+ T cells responsible for this early IL-4 response to L. major express a restricted TCR repertoire (Vß4-Va8) and respond to an I-Ad-restricted epitope of the Leishmania homologue of mammalian RACK1, designated LACK. The role of these cells and the IL-4 they produce for subsequent Th2 cell development and disease progression in BALB/c mice was demonstrated. Experiments have been undertaken to study the regulation of the rapid IL-4 production to L. major. In this report, we document an IL-2 mRNA burst, preceding the reported early IL-4 response, in draining lymph nodes of susceptible mice infected with L. major. Neutralization of IL-2 during the first days of infection redirected Thl cell maturation and resistance to L. major, through interference with the rapid IL-4 transcription in LACKreactive CD4+ cells. A burst of IL-2 transcripts also occurred in infected C57BL/6 mice that do not mount an early IL-4 response. However, although the LACK protein induced IL-2 transcripts in susceptible mice, it failed to trigger this response in resistant C57BL/6 mice. Reconstitution experiments using C.B.-17 SCID mice and LACK-reactive CD4+ T cells from IL-2-/- BALB/c mice showed that triggering of the early IL-4 response required autocrine IL2. Thus, in C57BL/6 mice, the inability of LACK-reactive CD4+ T cells to express early IL-4 mRNA transcription, important for disease progression, appears due to an incapacity of these cells to produce IL-2. A role for CD4+CD25+ regulatory T cells in the control of this early IL-4 production was investigated by depleting in vivo this regulatory T cell population. Depletion induced an increase in the early burst of IL-4 mRNA in the draining lymph nodes of BALB/c mice, and exacerbated the course of disease with higher levels of IL-4 mRNA and protein in their lymph nodes. The rapid IL-2 response to L. major is also significantly enhanced in BALB/c mice depleted of CD4+CD25+ cells. We further showed that transfer of 10~ BALB/c spleen cells that were depleted of CD4+CD25+ regulatory T cells rendered SCID mice susceptible to infection and allowed Th2 differentiation while SCID mice reconstituted with 10 control BALB/c spleen cells were resistant to infection with L. major and developed a Thl response. Treatment with a mAb against IL-4 upon infection with L. major in SCID mice reconstituted with CD25-depleted spleen cells prevented the development of Th2 polarization and rendered them resistant to infection. These results demonstrate that CD4+CD25+ regulatory T cells play a role in regulating the early IL-4 mRNA and the subsequent development of a Th2 response in this model of infection.

The Effect of Deicing Salt on Aggregate Durability, Progress Report HR-266, 1985

The Iowa DOT has been using rapid freezing in air and thawing in water to evaluate coarse aggregate durability in concrete since 1962. Earlier research had shown that the aggregate pore system was a major factor in susceptibility to D-cracking rapid deterioration. There are cases were service records show rapid deterioration of concrete containing certain aggregates on heavily salted primary roads and relatively good performance with the same aggregate in secondary pavements with limited use of deicing salt. A five-cycle salt treatment of the coarse aggregate prior to durability testing has yielded durability factors that correlate with aggregate service records on heavily salted primary pavements. X-ray fluorescence analyses have shown that sulfur contents correlate well with aggregate durabilities with higher sulfur contents producing poor durability. Trial additives that affect the salt treatment durabilities would indicate that one factor in the rapid deterioration mechanism is an adverse chemical reaction. The objective· of the current research is to develop a simple method of determining aggregate susceptibility to salt related deterioration. This method of evaluation includes analyses of both the pore system and chemical composition.

Metabolic attributes, yield and stability of milk in Jersey cows fed diets containing sodium citrate and sodium bicarbonate

The objective of this work was to evaluate the inclusion of sodium citrate and sodium bicarbonate in the diet of lactating Jersey cows, and its effects on the metabolic attributes, productivity and stability of milk. We evaluated urinary pH, levels of glucose and urea in blood, body weight, body condition score, milk yield, milk stability (ethanol test), and milk physicochemical properties of 17 cows fed diets containing sodium citrate (100 g per cow per day), sodium bicarbonate (40 g per cow per day) or no additives. Assessments were made at the 28th and 44th days. Supply of sodium citrate or bicarbonate has no influence on the metabolic attributes, productivity, body weight, and body condition score of the cows, neither on the composition and stability of milk.

Jätteenpolton tuhkien käsittelytekniikoiden ympäristövaikutukset

Jätteenpoltossa syntyvät tuhkat sisältävät paljon haitta-aineita, joiden vuoksi niitä ei yleensä voida suoraan sijoittaa kaatopaikoille. Käsittelyllä pyritään parantamaan tuhkien ominaisuuksia ja vähentämään haitta-aineiden liukoisuutta. Samalla kuitenkin käsittely kuluttaa raaka-aineita ja energiaa sekä aiheuttaa päästöjä. Tuhkien käsittelyn kokonaishyötyjä ja -haittoja ympäristön kannalta arvioitaessa tulisikin ottaa huomioon sekä käsiteltävän tuhkan parantuneet ominaisuudet että käsittelystä aiheutuneet ympäristökuormitukset. Tämän diplomityön tavoitteena oliselvittää jätteenpolton tuhkien käsittelystä aiheutuvia ympäristövaikutuksia tarkastelemalla esimerkinomaisesti neljää erilaista käsittelytekniikkaa (pesua, sementtikiinteytystä, Ferrox-prosessia ja vitrifiointia) sekä kahta muuta loppusijoitusvaihtoehtoa (mahdollisuutta sijoittaa tuhkat kaatopaikalle ilman käsittelyä ja kuljettamista Norjassa sijaitsevalle käsittely- ja loppusijoituslaitokselle). Tarkastelussa keskityttiin jätteenpolton ongelmallisimpiin tuhkajakeisiin, lentotuhkaan ja savukaasujen puhdistusjätteisiin eli APC-jätteisiin. Tavoitteena oli selvittää käsittelyvaihtoehdoista syntyvät ympäristökuormitukset ns. koko niiden elinkaaren ajalta, eli huomioiden käsittelyyn tarvittavien lisäaineiden valmistuksesta, itse käsittelyprosessista sekä loppusijoituksesta aiheutuvat kuormitukset. Tarkastelun perusteella eri käsittelyvaihtoehdot aiheuttavat hyvin erilaisia ja erisuuruisia ympäristökuormituksia. Lisäksi käsitellyn materiaalin ominaisuudet vaihtelevat huomattavasti käsittelytavasta riippuen. Tarkastelluista käsittelyvaihtoehdoista suurimmat ympäristökuormitukset ilmapäästöjen osalta aiheutuivat tyypillisesti joko käsittelyyn tarvittavien raaka-aineiden valmistuksesta tai itse käsittelyprosessin energiankulutuksesta. Loppusijoituksesta sen sijaan aiheutui ympäristöhaittoja kaatopaikkarakenteiden muodostamisesta sekä maaperään vapautuvista haitta-aineista, joiden määrä riippuu tuhkan käsittelyn tehokkuudesta.

Division of labor in insect societies : genetic components and physiological regulation

The shift from solitary to social organisms constitutes one of the major transitions in evolution. The highest level of sociality is found in social insects (ants, termites and some species of bees and wasps). Division of labor is central to the organization of insect societies and is thought to be at the root of their ecological success. There are two main levels of division of labor in social insect colonies. The first relates to reproduction and involves the coexistence of queen and worker castes: while reproduction is usually monopolized by one or several queens, functionally sterile workers perform all the tasks to maintain the colony, such as nest building, foraging or brood care. The second level of division of labor, relating to such non-reproductive duties, is characterized by the performance of different tasks or roles by different groups of workers. This PhD aims to better understand the mechanisms underlying division of labor in insect societies, by investigating how genes and physiology influence caste determination and worker behavior in ants. In the first axis of this PhD, we studied the nature of genetic effects on division of labor. We used the Argentine ant Linepithema humile to conduct controlled crosses in the laboratory, which revealed the existence of non-additive genetic effects, such as parent-of-origin and genetic compatibility effects, on caste determination and worker behavior. In the second axis, we focused on the physiological regulation of division of labor. Using Pogonomyrmex seed- harvester ants, we performed experimental manipulation of hibernation, hormonal treatments, gene expression analyses and protein quantification to identify the physiological pathways regulating maternal effects on caste determination. Finally, comparing gene expression between nurses and foragers allowed us to reveal the association between vitellogenin and worker behavior in Pogonomyrmex ants. This PhD provides important insights into the role of genes and physiology in the regulation of division of labor in social insect colonies, helping to better understand the organization, evolution and ecological success of insect societies. - L'une des principales transitions évolutives est le passage de la vie solitaire à la vie sociale. La socialité atteint son paroxysme chez les insectes sociaux que sont les fourmis, les termites et certaines espèces d'abeilles et de guêpes. La division du travail est la clé de voûte de l'organisation de ces sociétés d'insectes et la raison principale de leur succès écologique. La division du travail s'effectue à deux niveaux dans les colonies d'insectes sociaux. Le premier niveau concerne la reproduction et implique la coexistence de deux castes : les reines et les ouvrières. Tandis que la reproduction est le plus souvent monopolisée par une ou plusieurs reines, les ouvrières stériles effectuent les tâches nécessaires au bon fonctionnement de la colonie, telles que la construction du nid, la recherche de nourriture ou le soin au couvain. Le second niveau de division du travail, qui concerne les tâches autres que la reproduction, implique la réalisation de différents travaux par différents groupes d'ouvrières. Le but de ce doctorat est de mieux comprendre les mécanismes sous-jacents de la division du travail dans les sociétés d'insectes en étudiant comment les gènes et la physiologie influencent la détermination de la caste et le comportement des ouvrières chez les fourmis. Dans le premier axe de ce doctorat, nous avons étudié la nature des influences génétiques sur la division du travail. Nous avons utilisé la fourmi d'Argentine, Linepithema humile, pour effectuer des croisements contrôlés en laboratoire. Cette méthode nous a permis de révéler l'existence d'influences génétiques non additives, telles que des influences dépendantes de l'origine parentale ou des effets de compatibilité génétique, sur la détermination de la caste et le comportement des ouvrières. Dans le second axe, nous nous sommes intéressés à la régulation physiologique de la division du travail. Nous avons utilisé des fourmis moissonneuses du genre Pogonomyrmex pour effectuer des hibernations artificieHes, des traitements hormonaux, des analyses d'expression de gènes et des mesures de vitellogénine, ce qui nous a permis d'identifier les mécanismes physiologiques régulant les effets maternels sur la détermination de la caste. Enfin, la comparaison d'expression de gènes entre nourrices et fourrageuses suggère un rôle de la vitellogénine dans la régulation du comportement des ouvrières chez les fourmis moissonneuses. En détaillant les influences des gènes et de la physiologie dans la régulation de la division du travail dans les colonies d'insectes sociaux, ce doctorat fournit d'importantes informations permettant de mieux comprendre l'organisation, l'évolution et le succès écologique des sociétés d'insectes.

Cutting edge: alum adjuvant stimulates inflammatory dendritic cells through activation of the NALP3 inflammasome.

Adjuvants are vaccine additives that stimulate the immune system without having any specific antigenic effect of itself. In this study we show that alum adjuvant induces the release of IL-1beta from macrophages and dendritic cells and that this is abrogated in cells lacking various NALP3 inflammasome components. The NALP3 inflammasome is also required in vivo for the innate immune response to OVA in alum. The early production of IL-1beta and the influx of inflammatory cells into the peritoneal cavity is strongly reduced in NALP3-deficient mice. The activation of adaptive cellular immunity to OVA-alum is initiated by monocytic dendritic cell precursors that induce the expansion of Ag-specific T cells in a NALP3-dependent way. We propose that, in addition to TLR stimulators, agonists of the NALP3 inflammasome should also be considered as vaccine adjuvants.

Practical applications of a systematic approach to the chemical abatement of pollutants in water and air

The present dissertation is devoted to the systematic approach to the development of organic toxic and refractory pollutants abatement by chemical decomposition methods in aqueous and gaseous phases. The systematic approach outlines the basic scenario of chemical decomposition process applications with a step-by-step approximation to the most effective result with a predictable outcome for the full-scale application, confirmed by successful experience. The strategy includes the following steps: chemistry studies, reaction kinetic studies in interaction with the mass transfer processes under conditions of different control parameters, contact equipment design and studies, mathematical description of the process for its modelling and simulation, processes integration into treatment technology and its optimisation, and the treatment plant design. The main idea of the systematic approach for oxidation process introduction consists of a search for the most effective combination between the chemical reaction and the treatment device, in which the reaction is supposed to take place. Under this strategy,a knowledge of the reaction pathways, its products, stoichiometry and kinetics is fundamental and, unfortunately, often unavailable from the preliminary knowledge. Therefore, research made in chemistry on novel treatment methods, comprisesnowadays a substantial part of the efforts. Chemical decomposition methods in the aqueous phase include oxidation by ozonation, ozone-associated methods (O3/H2O2, O3/UV, O3/TiO2), Fenton reagent (H2O2/Fe2+/3+) and photocatalytic oxidation (PCO). In the gaseous phase, PCO and catalytic hydrolysis over zero valent ironsare developed. The experimental studies within the described methodology involve aqueous phase oxidation of natural organic matter (NOM) of potable water, phenolic and aromatic amino compounds, ethylene glycol and its derivatives as de-icing agents, and oxygenated motor fuel additives ¿ methyl tert-butyl ether (MTBE) ¿ in leachates and polluted groundwater. Gas-phase chemical decomposition includes PCO of volatile organic compounds and dechlorination of chlorinated methane derivatives. The results of the research summarised here are presented in fifteenattachments (publications and papers submitted for publication and under preparation).

Control and Simulation of Batch Crystallization

Concerning process control of batch cooling crystallization the present work focused on the cooling profile and seeding technique. Secondly, the influence of additives on batch-wise precipitation process was investigated. Moreover, a Computational Fluid Dynamics (CFD) model for simulation of controlled batch cooling crystallization was developed. A novel cooling model to control supersaturation level during batch-wise cooling crystallization was introduced. The crystallization kinetics together with operating conditions, i.e. seed loading, cooling rate and batch time, were taken into account in the model. Especially, the supersaturation- and suspension density- dependent secondary nucleation was included in the model. The interaction between the operating conditions and their influence on the control target, i.e. the constant level of supersaturation, were studied with the aid of a numerical solution for the cooling model. Further, the batch cooling crystallization was simulated with the ideal mixing model and CFD model. The moment transformation of the population balance, together with the mass and heat balances, were solved numerically in the simulation. In order to clarify a relationship betweenthe operating conditions and product sizes, a system chart was developed for anideal mixing condition. The utilization of the system chart to determine the appropriate operating condition to meet a required product size was introduced. With CFD simulation, batch crystallization, operated following a specified coolingmode, was studied in the crystallizers having different geometries and scales. The introduced cooling model and simulation results were verified experimentallyfor potassium dihydrogen phosphate (KDP) and the novelties of the proposed control policies were demonstrated using potassium sulfate by comparing with the published results in the literature. The study on the batch-wise precipitation showed that immiscible additives could promote the agglomeration of a derivative of benzoic acid, which facilitated the filterability of the crystal product.

Towards desired crystalline product properties: In-situ monitoring of batch crystallization

The objective of industrial crystallization is to obtain a crystalline product which has the desired crystal size distribution, mean crystal size, crystal shape, purity, polymorphic and pseudopolymorphic form. Effective control of the product quality requires an understanding of the thermodynamics of the crystallizing system and the effects of operation parameters on the crystalline product properties. Therefore, obtaining reliable in-line information about crystal properties and supersaturation, which is the driving force of crystallization, would be very advantageous. Advanced techniques, such asRaman spectroscopy, attenuated total reflection Fourier transform infrared (ATR FTIR) spectroscopy, and in-line imaging techniques, offer great potential for obtaining reliable information during crystallization, and thus giving a better understanding of the fundamental mechanisms (nucleation and crystal growth) involved. In the present work, the relative stability of anhydrate and dihydrate carbamazepine in mixed solvents containing water and ethanol were investigated. The kinetics of the solvent mediated phase transformation of the anhydrate to hydrate in the mixed solvents was studied using an in-line Raman immersion probe. The effects of the operation parameters in terms of solvent composition, temperature and the use of certain additives on the phase transformation kineticswere explored. Comparison of the off-line measured solute concentration and the solid-phase composition measured by in-line Raman spectroscopy allowedthe identification of the fundamental processes during the phase transformation. The effects of thermodynamic and kinetic factors on the anhydrate/hydrate phase of carbamazepine crystals during cooling crystallization were also investigated. The effect of certain additives on the batch cooling crystallization of potassium dihydrogen phosphate (KDP) wasinvestigated. The crystal growth rate of a certain crystal face was determined from images taken with an in-line video microscope. An in-line image processing method was developed to characterize the size and shape of thecrystals. An ATR FTIR and a laser reflection particle size analyzer were used to study the effects of cooling modes and seeding parameters onthe final crystal size distribution of an organic compound C15. Based on the obtained results, an operation condition was proposed which gives improved product property in terms of increased mean crystal size and narrowersize distribution.

Hapettavan BIMODES-mikrobientorjuntamenetelmän vaikutukset paperikoneella

The aim of this study was to examine the effects of oxidising BIMODES microbiological control program on three paper machine process. The chemicals used in BIMODES program are sodium hypochlorite (NaOCl) and bromo-chloro-di-methyl-hydantoin (BCDMH). The literary part of this study discusses the microbiological problems in paper making industry, describes functional mechanisms of oxidants and also introduces the BIMODES- program. In the experimental part the aim was to examine the effects of BIMODES in three different paper machines. The purpose was to find out the effects and changes in wet end chemistry, bacterial counts, in the other additives and also in the sheet defects and holes. The study also examines what are the most important measurements to control BIMODES dosing. In addition the optimal dosing level for each machine was tried to find out. It was found that there is a clear correlation between the total chlorine level and bacterial counts. Changes in the BIMODES dosing level can be measured by redox potential, but the correlation is very poor. BIMODES program doesn’t have straight influence to pH values, but if dosage level is too low the bacterial activity can affect degreasing in the pH value. In this study couldn’t find any consequential effects for the other additives by using BIMODES. In addition the optimal dosing levels were found and by following correct halogen levels it is possible to decrease bacterial levels for very low level.

Impacts des technologies de l'information sur les modes de coordination à travers quatre études en systèmes d'information

L'évolution de l'environnement économique, des chaînes de valeur et des modèles d'affaires des organisations augmentent l'importance de la coordination, qui peut être définie comme la gestion des interdépendances entre des tâches réalisées par des acteurs différents et concourants à un objectif commun. De nombreux moyens sont mis en oeuvre au sein des organisations pour gérer ces interdépendances. A cet égard, les activités de coordination bénéficient massivement de l'appui des technologies de l'information et de communication (TIC) qui sont désormais disséminées, intégrées et connectées sous de multiples formes tant dans l'environnement privé que professionnel. Dans ce travail, nous avons investigué la question de recherche suivante : comment l'ubiquité et l'interconnec- tivité des TIC modifient-elles les modes de coordination ? A travers quatre études en systèmes d'information conduites selon une méthodologie design science, nous avons traité cette question à deux niveaux : celui de l'alignement stratégique entre les affaires et les systèmes d'information, où la coordination porte sur les interdépendances entre les activités ; et celui de la réalisation des activités, où la coordination porte sur les interdépendances des interactions individuelles. Au niveau stratégique, nous observons que l'ubiquité et l'interconnectivité permettent de transposer des mécanismes de coordination d'un domaine à un autre. En facilitant différentes formes de coprésence et de visibilité, elles augmentent aussi la proximité dans les situations de coordination asynchrone ou distante. Au niveau des activités, les TIC présentent un très fort potentiel de participation et de proximité pour les acteurs. De telles technologies leur donnent la possibilité d'établir les responsabilités, d'améliorer leur compréhension commune et de prévoir le déroulement et l'intégration des tâches. La contribution principale qui émerge de ces quatre études est que les praticiens peuvent utiliser l'ubiquité et l'interconnectivité des TIC pour permettre aux individus de communi-quer et d'ajuster leurs actions pour définir, atteindre et redéfinir les objectifs du travail commun. -- The evolution of the economic environment and of the value chains and business models of organizations increases the importance of coordination, which can be defined as the management of interdependences between tasks carried out by different actors and con-tributing to a common goal. In organizations, a considerable number of means are put into action in order to manage such interdependencies. In this regard, information and communication technologies (ICT), whose various forms are nowadays disseminated, integrated and connected in both private and professional environments, offer important support to coordination activities. In this work, we have investigated the following research question: how do the ubiquity and the interconnectivity of ICT modify coordination mechanisms? Throughout four information systems studies conducted according to a design science methodology, we have looked into this question at two different levels: the one of strategic alignment between business and information systems strategy, where coordination is about interdependencies between activities; and the one of tasks, where coordination is about interdependencies between individual interactions. At the strategic level, we observe that ubiquity and interconnectivity allow for transposing coordination mechanisms from one field to another. By facilitating various forms of copresence and visibility, they also increase proximity in asynchronous or distant coordination situations. At the tasks level, ICTs offer the actors a very high potential for participation and proximity. Such technologies make it possible to establish accountability, improve common understanding and anticipate the unfolding and integration of tasks. The main contribution emerging from these four studies is that practitioners can use the ubiquity and interconnectivity of ICT in order to allow individuals to communicate and adjust their actions to define, reach and redefine the goals of common work.

FCC-yksikön NOx-päästöjen hallinta

Työssä tutkittiin typen oksidien (NOx) päästöjen muodostumista ja NOx-päästöjen poistomenetelmiä leijukatalyyttisessa krakkausyksikössä (FCC). Koeajossa Porvoon öljynjalostamon FCC-yksikössä tutkittiin NOx-päästöjen hallintaa CO-promoottorin (CO:n palamista edistävä lisäaine) annostelun avulla. Kirjallisuusosassa käsiteltiin NOx-päästöjen muodostumista FCC-yksikön regeneraattorissa. Katalyyttisten lisäaineiden vaikutusta NOx-päästöjen muodostumiseen tarkasteltiin laajasti. Katalyyttisten lisäaineiden ohella käsiteltiin muitakin NOx-päästöjen poistomenetelmiä. Koeajojen tarkoituksena oli optimoida FCC-yksikön katalyyttikiertoon annosteltavan CO-promoottorin määrä. CO-promoottorin sisältämä platina lisää NOx-päästöjen muodostumista regeneraattorissa, mutta vähentää jälkipalamista. Jälkipalamisen vuoksi regeneraattorin ylimenolinjan lämpötila nousee. Regeneraattorin ylimenolinjan lämpötila oli CO-promoottorin vähentämistä rajoittava tekijä, NOx-päästöjä pyrittiin vähentämään ilman merkittävää jälkipalamisen kasvua. Tuorekatalyytin platinapitoisuuden pienentäminen vähentää merkittävästi NOx-päästöjä.

Toms-ilmiön vaikutuksen mallinnus turbulenssivirtauksessa

Diplomityön tavoitteena oli laatia putkivirtaukselle laskentamalli, joka huomioi turbulenssin vaimentamiseen käytetyn lisäaineen vaikutuksen. Kirjallisuusosassa käsitellään turbulenssiin ja putkiston painehäviön laskentaan liittyviä asioita. Lisäksi käydään läpi virtausvastusta alentavien aineiden (DRA-aineiden) ominaisuuksia, vaikutusmekanismia ja niiden vaikutusta virtausominaisuuksiin sekä laskentamalleihin. Kokeellisessa osassa laadittiin kaksi Excel-pohjaista laskentamallia, joilla huomioitiin lisäaineen vaikutus putkiston virtausmäärien parantumiseen ja painehäviöihin. Malli I laskee ensin virtausvastuksen alenemisen (DR-efektin) annetuista lähtötiedoista. DR-efektien perusteella saadaan laskettua putkiston painehäviötiedot. Malli II laskee ensin virtausvastuskertoimet ilman DRA-ainetta ja DRA-aineen kanssa. Tämän jälkeen malli II laskee DR-efektin. Mallien vaatimat lähtötiedot koostuvat virtausmääristä, fluidin ominaisuuksista, polymeerin ominaisuuksista, lisäaineen annostelutiedoista ja putkiston tiedoista.

The tightness performance of pre-formed trays as package

Suojakaasupakkaaminen (MAP) on yleistynyt viime aikoina, koska sen avulla voidaan säilöä tuoreita tai vähän käsiteltyjä elintarvikkeita pidempään. Suurin syy hyllyiän pidentymiseen on hiilidioksidin aiheuttama mikrobien kasvun hidastuminen. Toisaalta huolena on patogeenisten mikrobien lisääntyminen anaerobisissa olosuhteissa. Pidempi säilyvyys voidaan saavuttaa myös käyttämällä vähemmän lisä- ja säilöntäaineita. Samalla suojakaasupakkaaminen kuitenkin vähentää myös pilaantuneiden tuotteiden määrää. Eniten suojakaasua käytetään lihan pakkaamisessa. Suojakaasupakkaamisessa elintarvikepakkaukseen syötetään normaalista huoneilmasta poikkeava kaasuseos. Pääasiassa kaasuseos koostuu hiilidioksidista, hapesta ja typestä. Lisäksi voidaan käyttää pieniä määriä hiilimonoksidia, argonia ja rikkidioksidia. Kaasuseoksen koostumus määräytyy elintarvikkeiden ominaisuuksien ja vaatimusten perusteella. Halutun kaasukoostumuksen tulee säilyä pakkauksessa muutamasta päivästä muutamaan kuukauteen riippuen elintarvikkeesta. Siksi tärkein pakkaukselta vaadittava ominaisuus on riittävä kaasutiiveys ja erityisesti hapenläpäisevyys. Koska suurin osa suojakaasupakkauksista on tällä hetkellä muovisia, tutkittiin kokeellisessa osiossa kartonkipakkausten tiiveysominaisuuksia. Kokeet tehtiin vertailemalla erilaisten vuoka- ja kansimateriaalien vaikutusta pakkausten tiiveyteen. Vuokien onnistuminen oli suurin yksittäinen tuloksiin vaikuttanut tekijä. Epäonnistuneen vuoan vaikutukset näkyivät myös saumauksessa, koska saumaustyökalun ja vuoan piti sopia yhteen. Lisäksi näkymättömät mikroreiät hankaloittivat todellisten vuotokohtien paikallistamista. Vuototestausten perusteella materiaaleille löydettiin kuitenkin viitteelliset optimiparametrit. Tärkein saumauksessa vaikuttanut tekijä oli sopivan saumauslämpötilan valinta. Prässättyjen vuokien laatu oli epätasainen. Siksi erityisesti rinnakkaisten kansitus- ja hapenläpäisymittausten väliset erot olivat merkitseviä. Lisäksi prässäys laski materiaalien hapenläpäisyominaisuuksia. Yksittäisten vuokien tiiveysominaisuudet täyttivät kuitenkin kaupallisille kaasupakkauksille asetetut vaatimukset. Vesihöyrynläpäisevyydessä materiaalin vesihöyrynläpäisy oli merkittävämpää kuin vesihöyryn kulkeutuminen vuotokohtien tai epäonnistuneiden saumojen kautta.