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Tesi sul tema "Sustainable solvent"
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1
Dakubo, Francis. "Sustainable Mining - Solving the Problem of Chalcopyrite Treatment/Processing - Leaching, Solvent Extraction & Flotation". Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/604862.
Testo completoAbstract (sommario):
Chalcopyrite ore forms the significant fraction of copper deposits in the earth crust. However, it is also the most difficult to treat using conventional ferric leaching methods. Smelting and electro-refining are currently the methods used in treating chalcopyrite concentrate obtained from froth flotation. Due to the ever increasing environmental requirements on smelters by the Environmental Protection Agency, new smelters are scarce in the United States. The scarcity of smelters has led to the urgent need to find a novel leaching method for the abundant chalcopyrite deposits in the USA and the rest of the world. This chapter(one) of the dissertation, therefore, investigated the leaching of chalcopyrite ore at pH 2 using a newly discovered oxidant (peroxodisulfate). Our results show that chalcopyrite leaching using peroxodisulfate follows a surface reaction shrinking core model. The activation energy of chalcopyrite leaching using peroxodisulfate ion was calculated as 41.1 kJ mol⁻¹. We also report that the leaching of chalcopyrite ore is affected by particle size and that stirring hurts leaching of chalcopyrite. Additionally, we found that peroxodisulfate can produce from sulfuric ions electrochemically. Hydrogen peroxide, permanganate, peroxodisulfate and ferric ions are all strong oxidants that have been researched in production pregnant leach solution (PLS) from chalcopyrite ore leaching. Because, solvent extraction is the next step in the recovery of copper from pregnant leach solutions (PLS). The questions, therefore, arises as to the fate of the organic extractant used in solvent extraction coming in contact with strong oxidant residual in the PLS. In chapter two of the dissertation, we studied the effect of strong oxidant residual in PLS on the degradation of organic extractants during solvent extraction of copper. Exposed organic extractants were analyzed using interfacial tension(IFT), Fourier Transform Infrared (FTIR) spectroscopy and CG LS. The results obtained from IFT and FTIR analysis, show no effect on the organic extractants exposed to sunlight and PLS containing the residual strong oxidant. Finally in chapter 3, the dissertation exams alternative water source for the flotation of chalcopyrite. Mineral flotation is a water-intensive process in mining. In order to sustain mining operations such flotation, which rely heavily on water, chapter 3 of the dissertation looks at using alternative water sources (in this case reclaimed wastewater) in the flotation of chalcopyrite ores; this effort is to limit the mining industries dependence on fresh ground water particularly in the Southwest of United States where water is a scarce commodity. The research studied the effect of reclaimed waste water on chalcopyrite flotation via contact angle and surface energy measurements. Furthermore, atomic force microscopy (AFM) and flotation tests were used to supplement the findings from contact angle and surface studies. We conclude here that the contact angle of a pure chalcopyrite surface was determined to be 75.6 degrees. We also found that pure chalcopyrite mineral surface is slightly polar with surface energies γCuFeS2^(LW) = 41.4 mJ/m² (apolar), γCuFeS2^(AB) = 2.9 mJ/m² (polar). The high value of the surface energy indicates pure chalcopyrite surface is slightly hydrophobic.
2
Draucker, Laura Christine. "Novel Solvent Systems for the Development of Sustainable Technology". Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16188.
Testo completoAbstract (sommario):
Sustainable development in chemical engineering offers technical, industrially relevant solutions to environmental and economic issues. This work focuses on three specific issues; improving solvent selection and reducing costly experimentation, improving catalyst recovery while reducing reaction time, and producing commercial viable biofuels by cost effective pretreatments and valuable side product extractions.
Novel solvent systems are a sustainable solution because they provide the ability to replace costly solvents with cheap, benign, and recyclable systems. Specifically, this work investigated the use of one novel solvent system, Gas Expanded Liquids (GXL).When a solvent is exposed to a gas in which it is miscible at modest pressures and temperatures, the liquid solvent becomes expanded, providing a unique tunable and reversible solvent with properties that can be much different then that of the solvent itself. If you apply this gas to a mixture of two liquids of a solid dissolved in a liquid phase, it can often provide a miscibility switch, aiding in separation, crystallization, and
recovery of products or catalysts. In this work several different applications for organic
solvents expanded with carbon dioxide were studied including miscibility switches for
catalyst recycle, pretreatment of biomass for improved bio-ethanol production, and
extraction of valuable chemicals from lignin waste in the pulp and paper industry. Solid
solubility models to improve solvent selection and predict unique solvent mixtures during
crystallization were also studied. The results reported here show promise for the use of
GXL novel solvent systems and solid solubility models in many sustainable applications.
3
Onwukamike, Kelechukwu Nnabuike. "Sustainable cellulose solubilization, regeneration and derivatization in a DBU-CO2 switchable solvent system". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0016/document.
Testo completoAbstract (sommario):
Source de carbone la plus abondante du règne végétal et non concurrentielle de la chaîne alimentaire, la cellulose est une alternative aux ressources fossiles crédible pour le développement de nouveaux matériaux polymères. Néanmoins, à ce jour, les nombreux travaux décrits dans la littérature et visant la valorisation et la modification chimique de ce biopolymère fascinant ne répondent pas suffisamment, ou tout au moins que très partiellement, aux critères de durabilité. Pour répondre à ces critères de développement durable, le caractère renouvelable de la cellulose et les concepts de procédés propres et de chimie ‘verte’, doivent être réellement pris en compte. Ceci implique un choix réfléchi des solvants et réactifs utilisés, une maîtrise des procédés de modification chimique et bien évidemment une évaluation de la pertinence des produits formés, pour lesquels les propriétés obtenues doivent être innovantes et supérieures aux matériaux polymères existants. Cette thèse se divise en trois parties principales, à savoir la solubilisation, la régénération et la modification chimique de la cellulose. Tout au long de ce travail, une attention particulière a été portée sur la durabilité de sa transformation chimique pour viser l’élaboration de matériaux cellulosiques processables et aux propriétés innovantes. Dans la première partie de la thèse, un système composé d’un catalyseur organique nucléophile (DBU) et de CO2 a permis la dissolution rapide de la cellulose dans le DMSO. Une étude détaillée visant à optimiser le système DMSO-DBU-CO2 a été réalisée grâce à un suivi par spectroscopie infrarouge in situ. Ainsi, jusqu'à 8 % massique de cellulose ont pu être dissous en 15 minutes à 30 °C sous une faible pression de CO2 (2-5 bars). L’originalité de ce système commutable (fixation-relargage réversible du CO2), par comparaison aux autres solvants classiques de la cellulose, inclut une recyclabilité plus facile par simple dépressurisation du CO2 et une solubilisation rapide et douce, à plus bas coût, en comparaison aux systèmes utilisant les liquides ioniques. La mise en évidence de la création de fonctions carbonate par réaction avec différents composés électrophiles tels les halogénures d’alkyle a permis d’avoir une connaissance approfondie de ce système. L'optimisation réussie d'un système ‘propre’ permettant la dissolution de la cellulose nous a conduit à étudier sa régénération. Dans cet objectif, des aérogels de cellulose ont été préparés par un procédé de solubilisation, coagulation et lyophilisation. Différents paramètres ont été examinés tels la concentration en cellulose, le solvant de coagulation ou encore la nature et concentration en super-base (DBU-CO2), sur les propriétés des aérogels (densité, morphologie, taille des pores). Les résultats obtenus démontrent que des aérogels avec une densité entre 0.05 et 1,2 g/cm3, des porosités entre 92 et 97 % et des tailles de pore entre 1,1 et 4,5 μm ont été obtenus. Enfin, l’analyse des aérogels par microscopie électronique à balayage (SEM), a révélé la formation de réseaux de cellulose interconnectés et macroporeux. La modification chimique de la cellulose pour l’élaboration de matériaux processables aux propriétés innovantes fait l’objet de la troisième partie de la thèse. Cette partie est divisée en deux sous-parties: la dérivatisation de la cellulose par réaction de transestérification d’une part, et par réaction multi-composants, d’autre part. Dans la première sous-partie et gardant à l'esprit les principes de la chimie verte, la nature unique du système commutable DBU-CO2 amenant un changement d’hydrophilie du squelette cellulosique a permis l’utilisation directe de l’huile de tournesol pour la transestérification de la cellulose. [...]As the most abundant source of carbon in our planet, without any competition with food or feed supplies, cellulose is a viable alternative to replace the widely used and unsustainable fossil-based polymers. However, the majority of researchers working on this fascinating biopolymer fail to incorporate sustainability considerations during cellulose chemical transformation to make materials. The consequence is a shift of the “environmental burden” to other stages of the process cycle. Therefore, to ensure sustainability, both the renewability feature of cellulose as well as sustainability considerations concerning its transformation processes are necessary. This implies to consider the solvent, the reactants, the derivatization process and the wastes produced as well as an evaluation of the suitability of the resultant products, for which relevant properties have to be obtained to compete with existing alternatives. This thesis is therefore divided into three main parts (solubilization, regeneration and derivatization of cellulose), and addresses the various concerns of sustainability during cellulose transformation with an end-goal of making processable materials.In the first part of the thesis, a sustainable solvent system for cellulose was investigated. In this regard, a detailed optimization study of the DBU-CO2 switchable solvent system was performed using in-situ infrared spectroscopy. Upon optimization, up to 8 wt.% cellulose could be dissolve within 15 min at 30 °C using low CO2 pressure (2-5 bar). What makes this solvent system sustainable, when compared to other classical cellulose solvents, includes: easier recyclability by simple release of the CO2 pressure, fast and mild solubilization and lower cost compared to ionic liquids. Finally, by successfully trapping the formed in-situ cellulose carbonate using an electrophile, a clearer understanding of this solvent system was established.The successful optimization of a sustainable solvent system for cellulose led to the second part of the thesis: the regeneration of cellulose. Here, the general solubilization and coagulation ways followed by freeze-drying was adopted to prepare cellulose aerogels. Various processing conditions such as cellulose concentration, coagulating solvent and super base, were investigated on their effect of the aerogels properties (density, morphology, pore size). The obtained results showed aerogels with densities between 0.05 and 1.2 g/cm3, porosities between 92 and 97 % and pore sizes between 1.1 and 4.5 μm. In addition, from scanning electron microscopy (SEM), open large macroporous inter-connected cellulose networks were observed.The derivatization of cellulose to make thermally processable materials is covered in the third part of the thesis. This part is divided into two sub-parts; transesterification and multicomponent reaction modification. [...]
Als Kohlenstoffquelle mit der größten Verfügbarkeit auf unserem Planeten, ohne Konkurrenz zur Lebens- und Futtermittelversorgung, stellt Cellulose eine interessante Alternative dar, um die vielfältig genutzten, nicht-nachhaltigen Polymere auf Erdölbasis zu ersetzen. Die Mehrheit der Forscher, die mit diesem faszinierenden Biopolymer arbeiten, vernachlässigt allerdings Überlegungen zur Nachhaltigkeit in die chemische Modifizierung von Cellulose bei der Herstellung von Materialien zu integrieren. Die Konsequenz dessen ist eine Verlagerung der Umweltbelastung auf andere Abschnitte des Prozess-Zyklus. Um Nachhaltigkeit sicherzustellen, sind deshalb sowohl der erneuerbare Aspekt von Cellulose als auch Überlegungen zur Nachhaltigkeit im Reaktionsprozess wichtig. Dies beinhaltet die Berücksichtigung des Lösungsmittels, die Reaktanden, des Derivatisierungsprozesses, die produzierten Abfälle sowie eine Beurteilung der Nachhaltigkeit der resultierenden Produkte, die relevante Eigenschaften aufweisen müssen um mit bestehenden Alternativen konkurrieren zu können. Diese Arbeit ist deshalb in drei Teile gegliedert (Löslichkeit, Rückgewinnung und Derivatisierung von Cellulose) und befasst sich mit den verschiedenen Aspekten der Nachhaltigkeit während der Umsetzung von Cellulose mit dem Ziel, verarbeitbare Materialien herzustellen.Im ersten Teil der Arbeit wurde ein nachhaltiges Lösungsmittelsystem für Cellulose untersucht. In diesem Zusammenhang wurde eine detaillierte Optimierungsstudie des DBU-CO2 schaltbaren Lösungsmittelsystems mittels in-situ Infrarot Spektroskopie durchgeführt. Nach der Optimierung konnten bis zu 8 Gew.-% Cellulose innerhalb von 15 min. bei 30°C und einem niedrigen CO2-Druck (2-5 bar) gelöst werden. Verglichen mit klassischen Lösungsmitteln für Cellulose weist dieses Lösungsmittelsystem verschiedene nachhaltige Aspekte auf: Einfaches Recycling durch entfernen des CO2-Drucks, schnelles und mildes Auflösen und geringere Kosten als ionische Flüssigkeiten. Durch erfolgreiches Abfangen des in-situ gebildeten Cellulose-Carbonats mit einem Elektrophil, konnte schließlich ein besseres Verständnis dieses Lösungsmittelsystems erreicht werden. Die erfolgreiche Optimierung eines Lösungsmittelsystems für Cellulose führte zum zweiten Teil der Arbeit: der Regenerierung von Cellulose. Hier wurde der bereits mit anderen Systemen beschriebene Weg von Lösen und Ausfällen, gefolgt von Gefriertrocknen übernommen, um Cellulose-Aerogele herzustellen. Verschiedene Bedingungen bei der Verarbeitung wie die Cellulose-Konzentration, Lösungsmittel zum Ausfällen und die Superbase und deren Effekt auf die Eigenschaften der Aerogele (Dichte, Morphologie und Porengröße) wurden untersucht. So wurden Aerogele mit einer Dichte von 0.05-1.20 g/cm3, Porositäten zwischen 92 und 97% und Porengrößen zwischen 1.1 und 4.5 μm erhalten. Zusätzlich wurden im Rasterelektronenmikroskop offene große und makroporöse, miteinander verbundene Cellulose-Netzwerke beobachtet. [...]
4
Whitaker, Mariah R. "Design of Heterogeneous Catalysts Incorporating Solvent-Like Surface Functionality for Sustainable Chemical Production". The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1563303994362428.
Testo completo
5
Fullarton, Claire. "Working towards a new sustainable rechargeable battery : zinc, conducting polymer and deep eutectic solvent system". Thesis, University of Leicester, 2015. http://hdl.handle.net/2381/31863.
Testo completoAbstract (sommario):
Electronically conducting polymers based on functionalised thiophenes and pyrroles have continued to stimulate academic interest as well as starting to be employed in practical applications and uses. This thesis describes studies of the electronic properties of mixed thiophene-pyrrole polymers (based on custom synthesised mixed monomer precursors) and polymers electrodeposited from commercially available monomers, pyrrole and 3,4-ethylenedioxythiophene, in respect to energy storage applications including batteries and ion selective membranes. In such applications the movement of ion and solvent through the polymer film during oxidation and reduction cycles is critical to application and function, e.g. charging rate, metal ion permeability or adhesion stability. Recently the unexpected behaviour of polypyrrole in choline chloride based ionic liquids has been described. These liquids are especially attractive because of their unique solubility profiles, high stability, low volatility and low toxicity. This thesis describes the electrochemical characterisation, DC capacitance behaviour and ion/solvent transport properties of conducting polymers using a range of electrochemical methodologies in combination with acoustic impedance electrochemical quartz crystal microbalance techniques (EQCM) and X-Ray Photo-electron Spectroscopy (XPS). The behaviour of several mixed thiophene-pyrrole films, polypyrrole and poly 3,4-ethylenedioxythiophene in different electrolyte media; deep eutectic solvents (DESs), conventional organic solvents and aqueous media are contrasted in this thesis. PEDOT and one of the mixed thiophene-pyrrole polymers (poly 2-(thiophene-2-yl)-1H pyrrole) gave the highest DC capacitances of the polymers investigated, with high values observed in both choline chloride based (Type III) and zinc based (Type IV) DESs. The ion dynamics of the polymers p-doping in the DESs, observed to fit gravimetric data recorded, was able to show a marked difference in the ion transfers between DES types and a conventional organic solvent, acetonitrile. Both polymers in acetonitrile and the zinc based DES (ZnCl2 / EG) satisfied the electro-neutrality condition through dominance of anion transfers. Whereas, polymers in the choline chloride based DES (Ethaline) satisfied the electro-neutrality condition through dominance of choline cation transfers (in the opposite direction to anion transfers). This research involved work towards the development of a new class of rechargeable batteries based on a Zinc-Polymer system incorporating a novel, inexpensive, environmentally sustainable solvent. This work is necessitated by the problems associated with petrol and diesel powered vehicles and the limitations of batteries available for electric vehicles.
6
BHANDARI, SHASHANK. "Design of a solvent recovery system in a pharmaceutical manufacturing plant". Thesis, KTH, Skolan för kemivetenskap (CHE), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190901.
Testo completoAbstract (sommario):
Solvents play a crucial role in the Active Pharmaceutical Ingredient (API) manufacturing and are used in large quantities. Most of the industries incinerate the waste solvents or send it to waste management companies for destruction to avoid waste handling and cross-contamination. It is not a cost effective method and also hazardous to the environment. This study has been performed at AstraZeneca’s API manufacturing plant at Sodertalje, Sweden. In order to find a solution, a solvent recovery system is modeled and simulated using ASPEN plus and ASPEN batch modeler. The waste streams were selected based on the quantity and cost of the solvents present in them. The solvent mixture in the first waste stream was toluene-methanol in which toluene was the key-solvent whereas in the second waste stream, isooctane-ethyl acetate was the solvent mixture in which isooctane was the key-solvent. The solvents in the waste stream were making an azeotrope and hence it was difficult to separate them using conventional distillation techniques. Liquid-Liquid Extraction with water as a solvent followed by batch distillation was used for the first waste stream and Pressure Swing Distillation was used for the second waste stream. The design was optimized based on cost analysis and was successful to deliver 96.1% toluene recovery with 99.5% purity and 83.6% isooctane recovery with 99% purity. The purity of the solvents was decided based on the quality conventions used at AstraZeneca so that it can be recovered and recycled in the same system. The results were favorable with a benefit of €335,000 per year and preventing nearly one ton per year carbon dioxide emissions to the environment. A theoretical study for the recovery system of toluene-methanol mixture was performed. The proposed design was an integration of pervaporation to the batch distillation. A blend of polyurethane / poly(dimethylsiloxane) (PU / PDMS) membrane was selected for the separation of methanol and toluene mixture. The results of preliminary calculations show 91.4% toluene recovery and 72% methanol recovery with desired purity.
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Shearouse, William C. "Development and mechanistic understanding of ball milling as a sustainable alternative to traditional synthesis". University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353089340.
Testo completo
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Zhang, Zhaoxi. "A study of solute-solvent interactions in methanol solutions : potential new sustainable technologies for refinery product upgrading/separating and methanol utilization". Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:c01e67d6-ed58-4c7c-8913-00f3e0a6408c.
Testo completoAbstract (sommario):
The upgrading of fluid catalytic cracking (FCC) gasoline is a significant refinery process which is required to decrease FCC gasoline's alkenes and organosulfur compounds (OSCs) levels to meet stringent, regulated specifications, whilst maintaining or increasing the octane number. The separation and recovery of alkene contents in gaseous alkene and alkane mixtures produced in the refining process is presently a substantial consumer of both energy and resources. The current processes for these upgrading or separation processes rely heavily upon energy - intensive technologies which require severe conditions and complex procedures, involving the widespread use of hydrogen. In this research, I explore new routes, based on novel and innovative chemistry, to improve the considerable energy consumption and overcome the above disadvantages in current FCC gasoline upgrading and gaseous alkene and alkane separation, and to develop lower cost, less energy-intensive approaches to these significant challenges. The potentially sustainable chemical - methanol - was introduced as the key to fulfil the aim of this research. After studying the microscopic nature of the hydrogen bond interactions between methanol and various hydrocarbons, alternative green and sustainable methanol-based "Extractive Refining/Extractive Distillation" approaches for upgrading the FCC gasoline/separating gaseous alkene and alkane has been developed to replace the conventional processes. In addition, what we define as the lower phase mixtures (LPMs) derived from the "Extractive Refining" processes were themselves utilised as feedstocks in a subsequent catalytic conversion process to yield high quality liquid fuel and other products. Through these processes the LPMs is able to be efficiently converted into high added value products such as gasoline, benzene, toluene, xylenes (BTX) etc. The feasibilities, mechanisms and advantages of these approaches and processes form the detailed investigations reported in this thesis. At the heart of these new processes is the fundamental issue of hydrogen bond formation between the extractant solvent, methanol, and the primary constituents of FCC gasoline, that need to be extracted, namely light alkenes and organic sulphur compounds, for the latter, typically taken as thiophene in this investigation . The work progresses from the discovery and evaluation of the applied "Extractive Refining/Extractive Distillation" process in FCC gasoline, back through to the fundamental nature, and investigation of the hydrogen bond between solute and solvent, through a variety of physicochemical techniques.
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Onwukamike, Kelechukwu Nnabuike [Verfasser], M. A. R. [Akademischer Betreuer] Meier e H. [Akademischer Betreuer] Cramail. "Sustainable Cellulose Solubilization, Regeneration and Derivatization in a DBU-CO$_2}$ Switchable Solvent System / Kelechukwu Nnabuike Onwukamike ; Betreuer: M.A.R. Meier, H. Cramail". Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1181190525/34.
Testo completo
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Chagnoleau, Jean-Baptiste. "Extraction de composés naturels à l'aide de solvants durables : expérience et modélisation". Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ5023.
Testo completoAbstract (sommario):
Les extraits naturels de plantes sont des ingrédients précieux pour un large éventail d'applications, notamment dans les industries cosmétiques ou pharmaceutiques ou dans les industries des parfums ou alimentaires. Mais l'extraction de ces composés naturels reste majoritairement réalisée à l'aide de solvants organiques volatils (COV) et de procédés ayant des impacts environnementaux importants. Dans le contexte récent de la chimie verte et de l'éco-extraction, des solvants alternatifs durables ont été développés pour remplacer les COV. Parmi ces solvants, les solvants biosourcés (BioSol), les solvants eutectiques profonds (DES) et les liquides ioniques (IL) ont fait l'objet d'intenses études au cours des deux dernières décennies. Néanmoins, les développements actuels des techniques d'extraction végétale reposent majoritairement sur des essais expérimentaux, ce qui limite le nombre de conditions et de solvants d'extraction pouvant être évalués. Pour remédier à cette limitation, plusieurs outils de modélisation ont été développés pour prédire les propriétés des solvants et soutenir le choix des solvants. Dans le chapitre I, la durabilité des solvants alternatifs sera discutée et des outils permettant de prédire les propriétés des solvants seront introduits.Dans le contexte de l'économie circulaire et du recyclage des déchets, les sous-produits sont désormais considérés comme une source alternative de composés naturels. Dans le chapitre II de ce travail, la valorisation des kiwis rejetés est proposée par l'extraction de composés bioactifs à l'aide de solvants durables à savoir des solvants eutectiques profonds (DES). Les résultats montrent que les extraits d'écorces de kiwi obtenus avec des DES à base d'acides carboxyliques présentent une activité antioxydante améliorée par rapport aux solvants conventionnels.Dans le domaine des industries de la parfumerie ou de l'agroalimentaire, les techniques d'extractions actuellement utilisées présentent plusieurs inconvénients. Dans le chapitre III de ce travail, des techniques alternatives ont été étudiées pour proposer de nouveaux ingrédients parfumés obtenus à l'aide de solvants durables. Des extraits de feuilles et de fruits de poivre rose (Schinus molle L.) ont été obtenus par extraction solide-liquide et hydrodistillation dans des solutions aqueuses de DES ou d'IL, tandis que les extraits de pétales de Rosa centifolia ont été obtenus par extraction solide-liquide dans des BioSol, DES et IL.Après extraction des plantes, les extraits naturels obtenus sont des mélanges chimiques complexes. Certaines applications nécessitant l'utilisation de composés purs, plusieurs techniques de séparation ont été développées. La chromatographie de partage centrifuge (CPC) est une technique de séparation utilisant les deux phases d'un système biphasique comme phase mobile et stationnaire pour effectuer des séparations chromatographiques préparatives. La possibilité d'utiliser des solvants durables et en particulier le DES pour former des systèmes biphasiques pour le CPC a été peu étudiée. Dans le chapitre IV de ce travail, le développement de systèmes biphasiques contenant du DES ont été étudiés comme systèmes potentiels de séparation des composés naturels. Enfin, le potentiel du modèle COSMO-RS dans la conception de systèmes biphasiques pour la séparation de composés naturels a été étudié. Les résultats démontrent que COSMO-RS prédit dans la plupart des cas les courbes binodales des systèmes biphasiques et les coefficients de partage des composés naturels avec une bonne précision. Ainsi, ces résultats indiquent que COSMO-RS peut être un outil puissant dans la conception de systèmes de séparation et de purification.Dans l'ensemble, ces travaux donnent un aperçu du potentiel de divers solvants durables pour l'extraction et la séparation de composés naturelsNatural plant extracts are valuable ingredients for a wide range of applications, particularly in the cosmetic or pharmaceutical industries or in the perfume or food industries. But the extraction of these natural compounds remains mainly carried out using volatile organic solvents (VOCs) and processes with significant environmental impacts. In the recent context of green chemistry and eco-extraction, sustainable alternative solvents have been developed to replace VOCs. Among these solvents, biobased solvents (BioSol), deep eutectic solvents (DES) and ionic liquids (ILs) have been the subject of intense studies over the last two decades. However, current developments in plant extraction techniques are mainly based on experimental trials, which limits the number of extraction conditions and solvents that can be evaluated. To address this limitation, several modeling tools have been developed to predict solvent properties and support solvent choice. In Chapter I, the sustainability of alternative solvents will be discussed and tools to predict solvent properties will be introduced.In the context of the circular economy and waste recycling, by-products are now considered as an alternative source of natural compounds. In chapter II of this work, the valorization of rejected kiwifruit is proposed by the extraction of bioactive compounds using sustainable solvents, namely deep eutectic solvents (DES). The results show that kiwi peel extracts obtained with carboxylic acid-based DES exhibit improved antioxidant activity compared to conventional solvents.In the field of perfumery or food industries, the extraction techniques currently used have several drawbacks. In chapter III of this work, alternative techniques were studied to propose new fragrance ingredients obtained using sustainable solvents. Extracts of leaves and fruits of pink pepper (Schinus molecular L.) were obtained by solid-liquid extraction and hydrodistillation in aqueous solutions of DES or IL, while extracts of petals of Rosa centifolia were obtained by solid-liquid extraction in BioSol, DES and IL.After extraction from the plants, the natural extracts obtained are complex chemical mixtures. Certain applications requiring the use of pure compounds, several separation techniques have been developed. Centrifugal partition chromatography (CPC) is a separation technique using the two phases of a biphasic system as mobile and stationary phase to perform preparative chromatographic separations. The possibility of using sustainable solvents and in particular DES to form biphasic systems for CPC has been little studied. In Chapter IV of this work, the development of biphasic systems containing DES were investigated as potential systems for separating natural compounds. Finally, the potential of the COSMO-RS model in the design of two-phase systems for the separation of natural compounds was investigated. The results demonstrate that COSMO-RS predicts in most cases the binodal curves of biphasic systems and the partition coefficients of natural compounds with good accuracy. Thus, these results indicate that COSMO-RS can be a powerful tool in the design of separation and purification systems.Overall, this work provides insight into the potential of various sustainable solvents for the extraction and separation of natural compounds
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Piovani, Laura. "Study of low environmental coating products: bio-based water products and solvent based products deriving from PET recycling". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Cerca il testo completoAbstract (sommario):
In this study three different projects are presented.The first consist in the analysis of two different bio resins with which a white and a transparent water-based base coat, a transparent water-based top coat and a water-based hydro-oil are formulated, applied and characterized, replacing the fossil based resins. First, the two bio resins are analyzed in terms of compatibility with other resins, additives and solvents and then the products formulated are characterized in terms of viscosity and chemical resistances. After the application, the products are analyzed in terms of filming capacity. The second project consists in formulating a coating system using the bio resin, suitable for use on bamboo toothbrushes in order to avoid the formation of mold. In particular two different formulations with two different viscosities are tested after having subjected the toothbrush to different pre-treatments based on H2O2 30 volumes, saturated solution of AgNO3. The third project consists in the formulation of two solvent-based clear coating systems: a base coat with a matte top coat and a base coat with a glossy top coat. For both systems an alkyd resin is used, whose fatty acid part consists of olive fatty acids, containing 12-14% recycled PET. The two system are formulated, applied and characterized in terms of viscosity, specific weight, transparency, elasticity, sand ability and chemical resistances. A comparison is made with the same products produced using the fossil based resins.The results show that the products formulated using the bio resins have similar characteristics of the standard resins therefore the bio products can replace the fossil based one. The toothbrushes coated with the coating system using the two new formulations are more resistant to the formation of mold. Finally, the two solvent-based coating system formulated using a resin containing PET can replace a coating system formulated with fossil based resin as they present similar characteristics.
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Kassner, Michelle Kimberly. "Novel sustainable solvents for bioprocessing applications". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26683.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Chemical Engineering, Georgia Institute of Technology, 2009.Committee Co-Chair: Eckert, Charles; Committee Co-Chair: Liotta, Charles; Committee Member: Bommarius, Andreas; Committee Member: Fernández, Facundo; Committee Member: Lu, Hang. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Hart, Ryan J. "Designing switchable solvents for sustainable process development". Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/39631.
Testo completoAbstract (sommario):
Novel solvents utilizing a reversible CO₂ induced property switch are presented. The synthetic procedure for designing the solvents is discussed, along with detailed characterizations on both solvent forms to serve as a tool for optimal solvent identification as well as future solvent design. A reflectance infrared spectroscopic technique is introduced to allow for the examination of CO₂ and solvent composition under high pressures and temperatures. The magnitude of solvent property changes afforded by this "switch" creates opportunities for sustainable processing; discussed are the application to coupling reactions and separations, and CO₂ capture. The switchable solvents are shown to serve as effective media for running reactions, with the switch providing facile recovery of products and catalysts for solvent recycling. Lastly, the switch itself is exploited to provide for the separation of CO₂ from low partial pressure feed streams, and structure-property relationships were successfully used to develop next generation materials with enhanced absorption capacities. The viscosity of the solvents, as a function of temperature and composition, is also presented.
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Vagnoni, Martina <1993>. "CO2 utilization and alternative solvents: effective tools for sustainable applications". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amsdottorato.unibo.it/10428/1/CO2%20UTILIZATION%20AND%20ALTERNATIVE%20SOLVENTS%20EFFECTIVE%20TOOLS%20FOR%20SUSTAINABLE%20APPLICATIONS.pdf.
Testo completoAbstract (sommario):
The growing concentration of CO2 in the atmosphere and its harmful consequences has led the scientific community to direct its efforts towards sustainable processes. Among the possible approaches, the use of CO2 and alternative solvents are two strategies that are having widespread diffusion.
In this work the reuse of CO2 is expressed by using it as a reaction reagent and as trigger to change the physical properties of a catalyst thus facilitating its recovery.
As regards the CO2 use as reagent, two catalytic systems have been developed for the conversion of CO2 and epoxides into cyclic carbonates, used in the synthesis of polymers and as aprotic solvents. Homogeneous catalysts made by choline-based eutectic mixtures and heterogeneous catalysts made from biopolymers and waste pyrolysis have been synthesized and tested on this reaction.
The carbonate interchange reaction (CIR) of a diol with a linear carbonate (as dimethyl carbonate) is an interesting alternative, for the synthesis of cyclic carbonates; as the second application of CO2 as polarity trigger, it was used for catalyst recovery. In fact DBU, here used as catalyst, is part of the so called “switchable solvents”: they can pass from a less-polar to a more-polar form (and from being soluble to non-soluble in the reaction mixture) when reacting with CO2 in presence of water or alcohols. Also in this case, heterogeneous catalysts made from biopolymers and waste pyrolysis have been synthesized and tested on CIR.
As for the use of alternative solvents, this work focuses on the use of Deep Eutectic Solvents (DESs). They are a new generation of solvents composed by a mixture of two or more substances, liquid at room temperature, and non-volatile. New and biobased DESs were here used: i) as reaction media to carry out chemoenzymatic epoxidation; ii) in the extraction of astaxanthin from microalgae culture.
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Donaldson, Megan Elizabeth. "Development and application of novel solvents for sustainable reactions and separations". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24749.
Testo completoAbstract (sommario):
Thesis (Ph.D.)--Chemical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Charles A. Eckert; Committee Co-Chair: Charles L. Liotta; Committee Member: Christopher W. Jones; Committee Member: Facundo M. Fernandez; Committee Member: Thomas F. Fuller.
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Marus, Gregory Alan. "The application of green chemistry and engineering to novel sustainable solvents and processes". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/43755.
Testo completoAbstract (sommario):
The implementation of sustainable solvents and processes is critical to new developments in reducing environmental impact, improving net efficiency, and securing economic profitability in the chemical and pharmaceutical industries.
In order to address the challenge of sustainability, researchers have used switchable solvents for both reaction and separation by utilizing a built-in switch to undergo a step change in chemical and physical properties. This allows us to facilitate reactions in the solvent then activate the switch to enable separation and facile product recovery. Subsequently, we can recover the solvent for reuse and avoid energy- or waste-intensive separation processes; thus we are developing and using these switchable solvents as sustainable and environmentally benign alternatives to traditional processes.
In this research, we enable the sustainable scale-up of a switchable solvent - piperylene sulfone - a "volatile" and recyclable DMSO replacement. In the development of this process, we improved the reaction performances and developed a green purification method.
Furthermore, we enable and demonstrate the implementation of a Meerwein-Ponndorf-Verley (MPV) reduction, a pharmaceutically relevant reaction, into a continuous flow platform. The innovation of continuous flow processes can replace traditional batch reaction technology, and is indeed a key research area that has been acknowledged by the pharmaceutical industry.
Additionally, we utilize the switchable sulfone solvents, piperylene and butadiene sulfone, for reaction and separation of HMF produced from monosaccharides as an alternative to a process which has been limited by an inefficient separation step.
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Ford, Jackson Walker. "Designing for sustainability with CO2-tunable solvents". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19866.
Testo completoAbstract (sommario):
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Dr. Charles A. Eckert; Committee Co-Chair: Dr. Charles L. Liotta; Committee Member: Dr. Amyn Teja; Committee Member: Dr. Dennis W. Hess; Committee Member: Dr. Victor Breedveld.
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Wickström, Sofia, e Jessica Danielsson. "Sustainable working capital management : A case study of five successful firms". Thesis, Uppsala universitet, Företagsekonomiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-227059.
Testo completoAbstract (sommario):
With the financial crisis, many firms suffered from liquidity shortages and needed to quickly change their way of working to release capital from the operations. Scholars argue that firms should handle immediate crisis with short-term measures first, and then change the underlying organizational routines to prevent recurrence. The management of working capital has received increased attention amongst corporate managers as a result of the crisis, whereby it is interesting to understand how firms can reduce their working capital in a sustainable way. By using the problem-finding and problem-solving approach, this study explores how successful firms have found and solved problems to make them sustainable. To answer the research question a multiple-case study is performed, where five firms are explored through interviews with key respondents. The study indicates that urgency is the main driver for both introducing and increasing the focus on working capital management. Different strategies for obtaining sustainable working capital management are found, where focus and commitment from the top management is suggested to be the glue that makes it last. It is furthermore suggested that managers have two main tools for creating and sustaining desired routines and practices; communication and control.
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Medina-Ramos, Wilmarie. "Water and carbon dioxide for sustainable synthesis and separation of pharmaceutical intermediates". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/52915.
Testo completoAbstract (sommario):
The research projects presented in this thesis are mainly focused toward green chemistry and engineering: developing innovative strategies to minimize waste, improve process efficiency and reduce energy consumption. Specifically, the work was centered on the design and applications of green solvents and processes for the sustainable production of pharmaceuticals. The first project was focused on the use of CO₂ to enhance Suzuki coupling reactions of substrates containing unprotected primary amines. This work established that exceptionally challenging substrates like halogenated amino pyridines (i.e. 4-amino-2-bromopyridine and 4-amino-2-chloropyridine) are suitable substrates for Suzuki coupling reactions under standard conditions using CO₂ pressures, without the need for protection/deprotection steps which are traditionally considered to be necessary for these reactions to proceed cleanly. The second project explored the use of water at elevated temperatures (WET) for the sustainable and selective removal of protecting groups. The favorable changes that occur in the physiochemical properties (i.e. density, dielectric constant and ionization constant) of water at elevated temperatures and pressures make it an attractive solvent for the development of sustainable, environmentally green processes for the removal of protecting groups. The water-mediated selective removal of protecting groups such as N-Boc, N-Acetyl and O-Acetyl from a range of organic model compounds was successfully achieved by tuning the temperature (125 to 275°C) or properties of water. The third project investigated the use of Organic-Aqueous Tunable Solvents (OATS) for the rhodium catalyzed hydroformylation of p-methylstyrene. This enables the reactions to be carried out efficiently under homogeneous conditions, followed by a carbon dioxide (CO₂) induced heterogeneous separation. Modest pressures of CO₂ induced the aqueous-rich phase (containing the catalyst) to separate from the organic-rich phase (containing the reactant), thus enabled an easy separation and recycling of catalyst. The use of Al(OtBu)₃ as a potent catalyst toward continuous Meerwein-Ponndorf-Verley (MPV) reductions was established in the fourth project. The MPV reduction of model compounds like benzaldehyde and acetophenone to their corresponding alcohols was investigated in continuous mode as a function of temperature and catalyst loading. These results established a roadmap for the pharmaceutical industry to document the implementation of continuous flow processes in their manufacturing operations.
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Fadhel, Ali Zuhair. "Designing for sustainability: applications of tunable solvents, switchable solvents, and catalysis to industrial processes". Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39646.
Testo completoAbstract (sommario):
The focus of this research was to improve the sustainability of various processes by employing tunable solvents, switchable solvents, and catalysis. In Chapter 2, we report applications of tunable solvents to metal and enzyme catalyzed reactions of hydrophobic substrates. Tunable solvents are defined as solvent that change properties rapidly but continuously upon the application of an external physical stimulus and we utilize these solvents to couple homogeneous reactions with heterogeneous separations. We developed organic-aqueous tunable solvents that utilize propane for efficient phase separation at moderate pressures around 1 MPa; for example the water contents in the propane-expanded THF is 3 wt% at 0.8MPa at 30°C. Also, we extended the use of CO2-organic-aqueous tunable solvents to a pharmaceutically-relevant reaction--the hydroformylation of p-methylstyrene. The homogeneous reactions provide fast rates with excellent yields. At 60°C, the reaction reaches completion after 180 minutes with 95% branched aldehyde yield. The CO2-induced heterogeneous separation of the product from the catalyst provides an efficient and simple way to remove 99% of the product, to retain 99.9% of catalyst, and to recycle the Rh-TPPMS catalyst for five consecutive reactions.
In chapter 3, we investigated the use of reversible ionic liquids (RevILs) for synthesis of nanoparticles. RevILs are formed by the reversible reaction of compounds with basic nitrogen functionalities (molecular liquid) with CO2 at ambient pressure to form a liquid salt (ionic liquid). We demonstrated that RevILs form microemulsions that can be switched-on by bubbling CO2 and switched-off by heating. These microemulsions solubilize ionic compounds such as chloroauric acid. We utilized these microemulsions as a template for controlled synthesis of gold nanoparticles. With 2-component RevILs, [TMBGH]+[O2COCH3]-/N-propyl-octylsulfonamide/hexane were used to form particles in the size range of 6-20 nm with an average particles size of 11.4±3.3. With 1-component RevILs, (3-aminopropyl)-tripropylsilane was used to prepare semi-spherical gold particles with an average size of about 20nm. The 1-component RevILs systems provide a simpler method to form microemulsions when compared to the 2-componenet RevILs systems since they eliminate the need for alcohols and surfactants.
In chapter 4, we developed a catalyst that efficiently decomposes hydrazine to selectively produce ammonia. This enables the use of the chemical propulsion hydrazine for electric propulsion as well. We prepared nickel, copper, cobalt, ruthenium, rhodium, and iridium nanoparticles that were supported on silica and we tested these silica-supported metals for the decomposition of hydrazine. To study the catalytic activity, we designed and constructed a continuous flow reactor. The results show that nano-nickel supported on silica is the most active and selective catalyst with 100% conversion of hydrazine and 94±3% yield of ammonia.
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Paggiola, Giulia. "Multi-perspective analysis of the applicability of bio-based solvents as sustainable options for biocatalysis". Thesis, University of York, 2016. http://etheses.whiterose.ac.uk/15797/.
Testo completoAbstract (sommario):
Biocatalysis and sustainable solvents are two increasingly popular instruments of the green synthetic toolkit. This thesis explores the use of bio-based solvents in reactions catalysed by Candida Antarctica lipase B, and discusses their greenness and wider applicability. Firstly, to clarify the mechanism of solvent influence on enzyme catalysis, a systematic multi-variable approach is applied for the first time. The results challenge the established theory which relied solely on partition coefficient, logP, revealing that catalytic performance is governed instead by the solvent’s ability to engage in hydrogen bonding. In addition, thermodynamic insight is given, with evidence of isokinetic effect and of genuine enthalpy-entropy compensation. Both effects were previously undocumented for such systems. Secondly, a strong case is made for citrus waste-derived solvents, D-limonene and p-cymene, as effective alternatives to typical petroleum-derived counterparts used in such processes. Their first use as media for biocatalysis is herein reported, in particular applied to the chemo-enzymatic synthesis of the pharmaceutical compound (S,S)-Reboxetine. Finally, novel methods from socio-economic sciences are employed to reveal the main barriers faced by users in the uptake of green solvents. As a result of a survey of stakeholder perception, the most pressing priorities to be addressed appear 1) cost, 2) lack of data, and 3) availability & supply. The third of these aspects is later examined in detail as part of a dedicated case-study, which compares D-limonene potential supply against toluene demand. While complete global substitution appears unlikely, the greatest potential is shown for citrus-growing countries such as Brazil, Spain, India and South Africa which could feasibly implement the substitution as exemplary models of bio-economy.
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Zaytseva, K. "Methods of formation scenarios for solving the problems of sustainable development of regions". Thesis, Видавництво СумДУ, 2012. http://essuir.sumdu.edu.ua/handle/123456789/26817.
Testo completo
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Nora, Perk. "Transformation Towards Sustainable Transportation : Solving the "First and Last-mile" Problem in Europe". Thesis, Blekinge Tekniska Högskola, Institutionen för fysisk planering, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-19583.
Testo completoAbstract (sommario):
The thesis emphasizes the transformation towards sustainable mobility and the role of urban planning for such transformation. The aim of this thesis is to provide a comprehensive overview of different examples of solving the so-called “the first and last-mile problem” (FMLM) (which is conceptualized as a major problem for the transformation towards sustainable forms of travel) which have been tested or implemented in European cities, as well as provide an understanding of the role of the planner in these examples. The following questions were asked: What solutions to the “First and last-mile” transportation problem are currently being tested in European cities? And what is the role of urban planning in enabling the different solutions? In order to answer the first research question, a comprehensive mapping was carried out, comprising of a literature- and an internet review. The identified solutions for the “first and last-mile” were grouped into two different categories the station-based — these include car-sharing, bike-sharing, ridesharing — and free-floating solution — including car-sharing, autonomous vehicles, bike-sharing, e-scooters, scooters, taxi-/ridesharing. The second research question was answered by interviewing transportation planners and project managers in Sweden and Finland about their perceived role regarding these different solutions. The analyses showed that urban planners adopt different roles in the solution-finding process, depending on the solution and the framework within the municipality. The three dominante roles that are taken by planners are the Regulator, Partner and Promoter.
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Song, Ingu. "Role of carbon dioxide in gas expanded liquids for removal of photoresist and etch residue". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/26473.
Testo completoAbstract (sommario):
Thesis (Ph.D)--Chemical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Hess, Dennis; Committee Member: Eckert, Charles; Committee Member: Frazier, Bruno; Committee Member: Henderson, Clifford; Committee Member: Liotta, Charles. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Hunter, Dale. "Facilitation of sustainable co-operative processes in organisations /". View thesis, 2003. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20031107.153926/index.html.
Testo completoAbstract (sommario):
Thesis (Ph.D.) -- University of Western Sydney, 2003."A thesis presented to the University of Western Sydney School of Social Ecology and Lifelong Learning in fulfilment of the requirements for the degree of Doctor of Philosophy" "March 2003" Bibliography: 238 - 249.
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Cong, Yongqing. "Sustainable Public Pension System for Florida Local Governments: Financial Solvency, Paradigm Switch, and Interperiod Equity". FIU Digital Commons, 2014. http://digitalcommons.fiu.edu/etd/1455.
Testo completoAbstract (sommario):
The issue of increasing unfunded pension liabilities of state and local governments has drawn increasing attentions in the last few years, especially after the 2008 stock market downturn. To maintain sustainability many state and local governments have put public pension reform at the top of their priority list. Previous research and practices provide two strategies to reform the current pension systems: Incremental changes to amend the existing defined benefit plans (DB plans), and the pension model switch from the DB model to defined contribution plans (DC plans).
This study aims to uncover reform strategies to cope for public pension systems. It first examined the appropriateness of the incremental reform strategies by identifying the determinants of the financial solvency of DB plans, utilizing the existing panel data of 151 local DB plans in Florida municipalities. Second, it gathered the primary data through the surveys and interviews with the Finance and HR directors in Florida local governments to analyze their perceptions of public pension reform and reveal their readiness to conduct the public pension paradigm switch. These approaches revealed the critical interperiod equity issue along with the impact of the two-tier benefit structure during the recent pension reform.
The results suggest that incremental reform strategies that reduce benefits and increase contributions are not effective in improving the financial solvency of public DB plans. The alternative reform approach—the DB-to-DC transition—is attractive to local governments because it will relieve the employer of the pension cost burden and transfer the investment risk to employees themselves. The transition is also politically palatable because the taxpayer sentiment is not supportive of what are perceived to be generous retirement benefit of public employees. Meanwhile, local governments are hesitant to implement the paradigm switch due to prohibitive transition costs, political pressure, and perhaps more importantly, the potential negative impacts to public recruitment and retention. Local officials do not perceive a reduction of morale with the two-tier benefit structure at the present time; they believe this issue will solve itself along the retirement of senior employees.
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Ada, Ketchie, Nehe Meret e Shapira Hila. "For the Creative Problem-Solver : An Integrated Process of Design Thinking and Strategic Sustainable Development". Thesis, Blekinge Tekniska Högskola, Sektionen för ingenjörsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4208.
Testo completoAbstract (sommario):
Since the dawn of humanity design has influenced human life. Today, facing the depletion of the socio-ecological system, increasing complex problems threaten humanity’s existence. Design has been a contributor to creating such problems, yet with appropriate tools can become a source for solutions. Design Thinking (DT) was identified as a possible approach that could contribute to Strategic Sustainable Development (SSD). The purpose of this thesis is to examine potential contributors and hindrances of the DT process with regards to SSD, and create a prototype for an integrated process that could help achieve more strategic and sustainable outcomes. With the use of the Framework for Strategic Sustainable Development (FSSD) as a lens to examine the above, along with interviews, Action Research and expert feedback, an integrated process was created. Results of the interviews and FSSD analysis helped shape two prototypes that were examined through the mentioned methods. It was indicated by participants of the Action Research and by experts that the prototype could help reach a strategic and sustainable outcome, and further refinement should be pursued. The final prototype is presented as part of the discussion, suggesting additional tools and actions that if included could create a possible Sustainable DT (SDT) process.
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Silva, Liliana Cristina Vieira da. "Development of a sustainable method for the extraction of lycopene and β-carotene from food wastes". Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15490.
Testo completoAbstract (sommario):
Mestrado em Biotecnologia - Biotecnologia AlimentarThe main objective of the present work is the study of a profitable process not only in the extraction and selective separation of lycopene and β-carotene, two compounds present in tomato, but also in its potential application to food industry wastes. This is one of the industries that produce larger amounts of wastes, which are rich in high value biomolecules with great economic interest. However, the conventional methods used to extract this kind of compounds are expensive which limits their application at large scale. Lycopene and βcarotene are carotenoids with high commercial value, known for their antioxidant activity and benefits to human health. Their biggest source is tomato, one of the world’s most consumed fruits, reason for which large quantities of waste is produced. This work focuses on the study of diverse solvents with a high potential to extract carotenoids from tomato, as well as the search for more environmentally benign solvents than those currently used to extract lycopene and β-carotene from biomass. Additionally, special attention was paid to the creation of a continuous process that would allow the fractionation of the compounds for further purification. Thus, the present work started with the extraction of both carotenoids using a wide range of solvents, namely, organic solvents, conventional salts, ionic liquids, polymers and surfactants. In this stage, each solvent was evaluated in what regards their capacity of extraction as well as their penetration ability in biomass. The results collected showed that an adequate selection of the solvents may lead to the complete extraction of both carotenoids in one single step, particularly acetone and tetrahydrofuran were the most effective ones. However, the general low penetration capacity of salts, ionic liquids, polymers and surfactants makes these solvents ineffective in the solid-liquid extraction process. As the organic solvents showed the highest capacity to extract lycopene and βcarotene, in particular tetrahydrofuran and acetone, the latter solvent used in the development process of fractionation, using to this by strategic use of solvents. This step was only successfully developed through the manipulation of the solubility of each compound in ethanol and n-hexane. The results confirmed the possibility of fractionating the target compounds using the correct addition order of the solvents. Approximately, 39 % of the β-carotene was dissolved in ethanol and about 64 % of lycopene was dissolved in n-hexane, thus indicating their separation for two different solvents which shows the selective character of the developed process without any prior stage optimization. This study revealed that the use of organic solvents leads to selective extraction of lycopene and β-carotene, allowing diminishing the numerous stages involved in conventional methods. At the end, it was possible to idealize a sustainable and of high industrial relevance integrated process, nevertheless existing the need for additional optimization studies in the future.
O principal objetivo do presente trabalho recai no estudo de um processo eficiente para a extração e fracionamento de licopeno e β-caroteno presentes no tomate, bem como na aplicação do processo a resíduos provenientes da indústria alimentar. Esta é uma das indústrias que produz das maiores quantidades de resíduos ricos em biomoléculas com valor acrescentado e com um elevado potencial económico. No entanto, os métodos convencionais para a extração deste tipo de compostos tornam-se dispendiosos, o que inviabiliza a sua aplicação em larga escala. O licopeno e o β-caroteno são carotenóides com elevado valor comercial, conhecidos pela sua atividade antioxidante e efeitos benéficos para a saúde humana. A sua maior fonte é o tomate, um dos frutos mundialmente mais consumidos, razão pela qual as quantidades de resíduos produzidos são consideráveis. Este trabalho centra-se no desenvolvimento de um processo que permita a extração e fracionamento eficientes destes carotenóides a partir do tomate, considerando o uso de solventes mais benignos que os estudados até ao momento. Adicionalmente, foi igualmente desenvolvido o processo de fracionamento em contínuo, considerando a futura aplicação industrial do mesmo. Assim, iniciou-se o presente trabalho com a extração destes dois carotenóides utilizando um conjunto de solventes comuns e alternativos, nomeadamente, solventes orgânicos, sais convencionais, líquidos iónicos, polímeros e surfatantes. Nesta etapa avaliou-se a capacidade de extração de cada um dos solventes. Os resultados obtidos demonstraram que uma seleção adequada do solvente pode conduzir à extração completa dos dois carotenóides numa única etapa de extração, sendo que a acetona e o tetrahidrofurano se revelaram os mais eficazes, sendo os sais, líquidos iónicos, polímeros e surfatantes pouco eficazes no processo de extração sólido-líquido, pela sua geral baixa capacidade de penetração na biomassa. Após demonstrar a elevada capacidade dos solventes orgânicos na extração do licopeno e β-caroteno, nomeadamente tetrahidrofurano e acetona, este último solvente foi usado no desenvolvimento de processo de fracionamento, recorrendo-se para isso ao uso de solventes estratégicos. Este passo foi desenvolvido com sucesso a partir da manipulação das solubilidades de cada um dos compostos de interesse em etanol e n-hexano. Os resultados obtidos confirmaram a possibilidade de fracionamento dos compostos alvo, pela adição ordenada dos solventes. Cerca de 39% do β-caroteno ficou dissolvido no etanol e cerca de 64% de licopeno encontrava-se dissolvido no n-hexano, indicando assim a sua separação para dois solventes distintos o que demonstra o caráter seletivo do processo desenvolvido, sem qualquer etapa prévia de otimização. Este estudo revelou que a utilização de solventes orgânicos conduz à extração seletiva de licopeno e β-caroteno, permitindo a eliminação de inúmeras etapas descritas pelos métodos convencionais. Por fim, foi possível idealizar e desenvolver um processo integrado sustentável e de relevância industrial.
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Hunter, Dale. "Facilitation of sustainable co-operative processes in organisations". Thesis, View thesis, 2003. http://handle.uws.edu.au:8081/1959.7/482.
Testo completoAbstract (sommario):
This thesis explores the quality and sustainability of facilitated co-operative processes in organisations, and the difficulties and opportunities associated with this way of working. Three complementary research methods have been used: a survey, an Internet dialogue and a co-operative inquiry of facilitators, managers and academics. The survey revealed that facilitators have diverse and sometimes contradictory approaches to their organisational work, co-operative processes are not easy to sustain within hierarchical organisations, and that facilitator ethics need clarification. The development of a Statement of Values and Code of Ethics by the International Association of Facilitators formed the content for the Internet dialogue part of this research. The co-operative inquiry highlighted that sustainable co-operation depends on embodied whole people connecting with love and compassion, and with the commitment and courage to speak their own truth and deeply engage with the collective wisdom of the group. It is shown that co-operative organisational forms, methods, processes, values and ethics are only part of what is needed to support co-operative endeavour. Underpinning all of these are ways of being that are learnt through modelling and mutually supportive interactions between persons in relationship. These ways of being need to be transmitted along with conceptual frameworks, processes and methods for ‘co-operacy’ to be sustainable in groups and organisations
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Nixon, Emily Cummings. "Silanes in sustainable synthesis: applications in polymer grafting, carbon dioxide capture, and gold nanoparticle synthesis". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45847.
Testo completoAbstract (sommario):
Vinyltrialkoxysilanes are grafted onto polyolefins via a radical mechanism; in a subsequent step, the pendant alkoxysilanes hydrolyze and condense upon exposure to water, resulting formation of crosslinks. Straight chain hydrocarbons were used as model compounds to investigate the regioselectivity of vinyltrimethoxysilane grafting. To stabilize the water-sensitive grafted products, the methoxy groups were substituted using phenyllithium. It was found that this reaction must be carried out for a minimum of three days to ensure full substitution. The grafted products were then separated on a weight basis using semi-preparative HPLC. Analysis of the di-grafted fraction using edited HSQC and HSQC-TOCSY NMR showed that radical propagation occurs via 1,4- and 1,5-intramolecular hydrogen shifts along the hydrocarbon backbone, resulting in multiple grafts per backbone. Post-combustion carbon capture targets CO₂ emissions from large point sources for capture and sequestration. A new class of potential carbon capture agents known as reversible ionic liquids (RevILs) has been synthesized and evaluated in terms of potential performance parameters (e.g. CO₂ capacity, viscosity, enthalpy of regeneration). These RevILs are silylated amines, which react with CO₂ to form a salt comprising an ammonium cation and a carbamate anion that is liquid at room temperature. Structural modifications of the basic silylamine skeleton result in drastic differences in the performance of the resulting RevIL. Systematic variation of the silylated amines allowed determination of a structure-property relationship, and continued iterations will allow development of an ideal candidate for scale-up. The properties and potential applications of gold nanoparticles (AuNP) are highly dependent on their size and shape. These properties are commonly controlled during liquid-phase synthesis through the use of capping agents, which must be removed following synthesis. Reverse micelles can also be used to control the morphology of AuNP during their synthesis. When RevILs are used in the formation of these reverse micelles, either as the disperse phase or as the surfactant, the built-in switch can be used to release the nanoparticles following their synthesis. This release on command could decrease the post-synthetic steps required to clean and purify AuNP prior to use. We have successfully synthesized AuNP using a number of different RevILs.
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Mario, Benini. "Improving Decision Making in Real-world Applications by Solving Combinatorial Optimization Problems". Doctoral thesis, Università di Siena, 2022. https://hdl.handle.net/11365/1221594.
Testo completoAbstract (sommario):
The motivation for this work is to study complex real-world scenarios and provide tools that can actually improve decision-making in those problems. To do so, we mainly adopt techniques from the fields of Operations Research and Combinatorial Optimization.
In this dissertation, we focus on three real-world applications from different industries that can be modeled as combinatorial optimization problems and address them with operations research techniques. The dissertation is divided in chapters, each of which is related to a different topic.
In Chapter 1, a problem concerning the transportation of biological samples from draw centers to a main laboratory for analysis is presented. The problem arises from a healthcare application in Bologna, Italy, where the healthcare authority decided to centralize the analysis of all biological samples of the area to a main laboratory, in order to exploit economies of scales and reduce the costs for samples’ analysis. Of course, such an improvement goal also created a new complex problem: all the samples must be transported from draw centers to the main lab. A fleet of vehicle is available for the transportation and must collect the samples from draw centers during given times of the day and deliver them within a certain time, since samples are perishable. Vehicles can also exploit the existence of dedicated centers that can extend the lifespan of the samples and where samples can be transferred from one vehicle to another. It is clear from this brief description how hard it could be to decide which is the routing of all the vehicles which minimizes the traveling costs while delivering all samples on time. For this problem we developed different mixed integer linear programming models, metaheuristic algorithms, and grouping policies for the samples that are able to tackle the complexity of the problem and improve routing decisions. All methods have been tested through an extensive computational campaign using real-world data, showing the effectiveness of the proposed approaches.
In Chapter 2, a problem related to the agricultural industry is presented. The problem arises from a real-world application in Italy and it is that of planning the use of the available land of a farm for a given number of years, given a set of crops that can be grown. The objective is to maximize the farmer’s profit, but the farmer is subject to several rules both from an agronomic and from a regulation point of view. In fact, many constraints exist regarding agronomic principles, such as maximum replanting, botanical family constraints and crop rotation issues. One of the goals of this work is indeed that of evaluating the risks and benefits of following or not the best practices regarding crop rotation issues in the Mediterranean pedo-climatic context. Furthermore, we want to evaluate the effectiveness of public and private initiatives regarding sustainable agriculture. In fact, it is more and more important nowadays to face these challenges in the food supply chain, which is one of the most discussed industries when it comes to sustainability. In particular, we analyze two different initiatives, namely the Common Agricultural Policy by the European Union and “La Carta del Mulino” by Barilla Group S.p.A.. Both initiatives introduce economic incentives for the farmers following virtuous behaviors from a sustainability point of view. Practically, these behaviors are constraints increasing the complexity of the problem and the difficulty in the decision-making process. For this problem, we will give a formal characterization and study its complexity, also analyzing special cases. We will also present a network-flow based model to solve a special case of the problem and integer linear programming models developed to solve three variants accounting for different sustainability scenarios. Real-world data from 23 Italian farms were used in an extensive computational campaign. The analysis of the results shows that the models can be helpful tools for farmers to plan their production and for authorities to evaluate the effectiveness (and efficiency) of their sustainability initiatives.
In Chapter 3, we discuss a problem concerning the sequencing of unreliable jobs on parallel machines. Even if the problem is not taken from a specific application, it may have several applications in real-world scenarios, such as in manufacturing and planning of complex computations on multi-processors computers. In this problem, we have n unreliable jobs providing a reward when successfully completed, but each job has a probability of not being carried out. We have m parallel identical machines at our disposal, and we want to schedule the jobs on the machines in order to maximize the total expected reward. To increase the probability of completing the jobs, we create m copies of each job and schedule each copy on a different machine. For this problem, we will present a complexity analysis showing that the problem is NP-complete for two machines. For the problem with two machines, we derived some theoretical properties and developed a quadratic integer programming model, a tabu search algorithm, and an upper bound based on the Three-Dimensional Assignment problem. A computational campaign on different sets of instances shows that the tabu search outperforms the model. Then we focused on the general case with m machines. In particular, we developed several heuristics and proved some theoretical results, including the worst case performance guarantee of two heuristics. We also devised a generalized tabu search algorithm and a new, improved, upper bounding scheme based on a relaxation of the problem. Computational experiments are performed for the new methods on the problems with two and three machines. The results show that good optimality gaps are reached on all the instances.
32
Sacadura, João Arriaga e. Cunha Cabral de. "Consulting to social entrepreneurship initiatives - using business skills to help solve social problems: ERG: a sustainable approach". Master's thesis, NSBE - UNL, 2010. http://hdl.handle.net/10362/10314.
Testo completoAbstract (sommario):
A Work Project, presented as part of the requirements for the Award of a Masters Degree in Management from the NOVA – School of Business and EconomicsEscolinha de Rugby da Galiza is a Social Entrepreneurship project from Santa Casa da Misericórdia de Cascais that uses an innovative approach to social integrate children from the community of Fim do Mundo. Through the study and analysis of this project, it was identified the need to improve the sustainability approach currently used. A set of proposals were developed to diversify its sources of donations and generate its own revenues in order to guarantee its longterm sustainability.
33
Boehme, Michelle. "Towards a tripartite partnership for sustainable development in the Rustenburg platinum region / Michelle Boehme". Thesis, North-West University, 2006. http://hdl.handle.net/10394/158.
Testo completoAbstract (sommario):
Development has always been problematic especially in the mining sector where it
often takes place at a rapid pace. Not only is the physical environment influenced but
other aspects such as legislation and the relationship between role players are also
influenced.
The focus of this thesis is tripartite partnership formation between business, local
government and the community for sustainable development in the Rustenburg
platinum region. In essence the study was about answering the broad question of
"how can one improve the chances of setting up a sound foundation, that in turn can
lead to a successful, integrated, cooperative and unified partnership in the
Rustenburg platinum region?"
In an attempt to answer the above, both a theoretical and practical approach was
used. Functionalism and the exchange theory were used to set up practical
guidelines for successful partnership formation. The thesis also investigated how
appropriate these two theories are for the mining industry in South Africa today, i.e.
they were validated against the data obtained from the study. In addition, other
existing case studies in the mining industry were studied in order to validate the
guidelines formulated from the two theories.
At a methodological level, expanded qualitative data analyses were applied in a
comprehensive manner to ensure a close relationship between empirical data and
theory. The empirical data was gathered both by desk research and by in-depth
personal interviews.
The results of the study produced some models of how a partnership could be
structured to function optimally. As part of the results an "ideal" model for the
partnership in the Rustenburg platinum region was created and the set of guidelines
was ranked according to its importance in the Rustenburg platinum region. Should
these guidelines and this model be used the chances of setting up a successful,
integrated, cooperative and unified partnership in the Rustenburg platinum region
could be significantly increased.Thesis (Ph.D. (Sociology))--North-West University, Potchefstroom Campus, 2006.
34
Fournier, Antoine. "Développement de procédés écoresponsables pour la synthèse de solvants et d'organocatalyseurs biosourcés". Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCK046/document.
Testo completoAbstract (sommario):
Les oxazolidinones sont des composés prometteurs pour des applications industrielles, mais aucune méthode ne convient à ce jour pour les produire à large échelle, à cause de l'utilisation de réactifs et de catalyseurs métalliques nocifs pour la santé et l'environnement. Une nouvelle méthode de synthèse de ces composés a donc été élaborée en utilisant des aminoalcools et du carbonate de diéthyle. Cette réaction est catalysée par un hydrogénocarbonate d'imidazolium biosourcé qui est produit par voie électrochimique afin de réduire son impact sur l'environnement.Cette méthode de synthèse d'oxazolidinones a ensuite été appliquée à la synthèse d'une oxazolidinone biosourcée. Pour cela, la synthèse d'un aminoalcool a été réalisée, et sa structure a été établie à partir de réactifs pouvant être issus de ressources renouvelables. La voie de synthèse a fait l'objet de modifications pour permettre la production de l'aminoalcool à plus grande échelle dans des conditions plus sûres.La seconde thématique de ces travaux porte sur les liquides ioniques, des sels liquides très peu volatils, couramment utilisés comme solvants. Ces composés sont généralement chers, ainsi, plutôt que de les éliminer à la fin de leur utilisation, il est plus intéressant de les recycler. Mais leur faible volatilité empêche leur recyclage par distillation, contrairement aux solvants organiques usuels. Il a ainsi été développé une première méthode électrochimique, économe en énergie, qui permet le recyclage de liquides ioniques biosourcés par la formation d'un hydrogénocarbonate d'imidazolium intermédiaire. Cette méthode a été comparée à d'autres procédés de recyclage grâce à une étude préliminaire du cycle de vie.Mots clés : oxazolidinone, aminoalcool, imidazolium, liquide ionique, biosourcé, recyclage, électrochimie, développement durable, écoconception, cycle de vieOxazolidinones are promising compounds for industrial applications, but nowadays there is not convenient method to produce them on large scale, because of the use of reactants and metallic catalysts harmful for health and environment. A new synthesis method of these compounds was thus elaborated using aminoalcohols and diethyl carbonate. This reaction is catalysed by a biobased imidazolium hydrogen carbonate which is produced by an electrochemical pathway in order to reduce its impact on the environment.This oxazolidinones synthesis method was then applied to the synthesis of a biobased oxazolidinone. To achieve this, an aminoalcohol synthesis was realised, and its structure was established from reactants that can come from renewable resources. The synthesis pathway was the object of modifications to permit the production of the aminoalcohol on a larger scale in safer conditions.The second thematic of these works is based on ionic liquids, very low volatile liquid salts, commonly used as solvents. These compounds are usually expensive, so, rather than to eliminate them at the end of their use, it is more interesting to recycle them. But their low volatility prevents their recycling by distillation, unlike common organic solvents. So, a first electrochemical method was developed, low energy consuming, permitting the recycling of biobased ionic liquids by the formation of an imidazolium hydrogen carbonate as intermediate. This method was compared with other recycling processes through a preliminary life cycle study.Keywords: oxazolidinone, aminoalcohol, imidazolium, ionic liquid, biobased, recycling, electrochemistry, sustainable development, eco-design, life cycle
35
George, John H. "Preparing Math Deficient University Students for STEM Achievement and Sustainable Learning". Youngstown State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1369580586.
Testo completo
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Lindeberg, Anna, Claudia Dina, Håkan Augustsson e Mariana Vasileva. "Importance of Leadership Competencies for the Transition to Sustainable Healthcare in Sweden". Thesis, Blekinge Tekniska Högskola, Institutionen för strategisk hållbar utveckling, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20027.
Testo completoAbstract (sommario):
Our unsustainable way of living has created a precondition for the emergence of more and new illnesses, jeopardizing the overall health of society. The Swedish healthcare system faces complex challenges that threaten its ability to live up to its obligations as stated in the law. It is proven that leaders in public organisations can have a substantial function in leading towards sustainability. Leadership competencies have a big role to play in that journey.This thesis explores the complex challenges administration leaders in the healthcare sector of two Swedish public organisations – Region Blekinge and Västra Götalandsregionen face when it comes to sustainability. The Framework for Strategic Sustainable Development is used to analyse the complexity and the sustainability within the study’s context. The Framework of Sustainability Research and Problem-solving Competence is utilized to understand the application, the relevance of the key competencies in sustainability in leadership, as well as the barriers in applying them, to deal with challenges. The conclusions are based on documentary analysis and semi-structured interviews. The results show the need for all key competencies, with biggest emphasis being put on systems thinking, interpersonal, intrapersonal and implementation. The findings reveal potential enablers and barriers for the organisations in moving society towards sustainability.
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Mahram, Mona, e Sadegh Shabnam Marboot. "Environmental impact and toxicity of chemicals used at University College of Borås". Thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-19889.
Testo completo
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Spaulding, Jeannette. "Tackling Wicked Problems : The Development of a New Decision-Making Tool, Applied to the Estonian Oil Shale Conundrum". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-226505.
Testo completoAbstract (sommario):
Wicked problems are a special subset of particularly complex issues that current problem-solving tools fail tofully address. Because of this deficiency, a new tool for evaluating and resolving wicked problems must be developed. Theories such as anti-positivism and systems thinking are explored in order to understand the nature of wicked problems, which are often defined by the involvement of multiple stakeholders as well as non-linear interrelations between various elements of the problem. Although traditional problem-solving methods are inadequate for wicked problems, there are certain tools that are more appropriate for handling such problems. These tools include the analytic hierarchy process, positional analysis, mess maps and heat maps. With their organized structures, visual languages and collaborative processes, these methods provide features that are well suited for tackling wicked problems. However, no single tool incorporates all of the necessary features. Therefore, a combination of the tools explored can yield a new and even more effective tool for wicked problems. This new tool, called STORM, is demonstrated through an evaluation of oil shale exploitation in Estonia. With Estonia currently dependent on energy from oil shale despite the environmental drawbacks, the situation is an ideal example of a wicked problem. The Estonian example shows how STORM can provide a greater understanding of wicked problems and allow resolutions to be negotiated. As sustainable development issues are usually considered to be wickedto sustainable development research.
39
Escárcega, Bobadilla Martha Verónica. "Organometallic compounds and metal nanoparticles as catalysts in low environmental impact solvents". Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/9114.
Testo completoAbstract (sommario):
Durant les darreres dècades, el disseny de processos en el marc de la química sostenible ha anat creixent de forma exponencial. La recerca constant de processos mes benignes amb el medi ambient ha implicat un gran esforç per obtenir millors rendiments mitjançant l'activació de llocs específics, i possant especial èmfasi amb el control de la quimio-, la regio- i la enantioselectivitat, punts crucials per a l'economia atómica. En aquest sentit, els dissolvents juguen un paper crític, i com podrà veure's al llarg d'aquesta memòria..Aquesta Tesi s'enfoca en l'ús de mitjans de reacció alternatius i sostenibles, com són els líquids iònics (ILs), el diòxid de carboni supercrític (scCO2) i la barreja de ambdós dissolvents, amb l'objectiu de disminuir l'ús de dissolvents orgànics convencionals i la seva aplicació en els següents processos catalítics: hidrogenació asimètrica, reacció de Suzuki d'acoblament creuat C-C, reacció d'alquilació al·lílica asimètrica i la hidrogenació de arens.
In the last decades, the design of processes in the framework of the sustainable chemistry has been exponentially growing. The constant searching of cleaner processes has led to a lot of effort to obtain higher yields by activation of specific sites, and improving chemo-, regio- and enantio-selectivities, which are crucial from a point of view of an atom economy strategy. In this sense, solvents play a critical role.
This PhD thesis focuses on the use of alternative sustainable reaction media such as ionic liquids (ILs), supercritical carbon dioxide (scCO2) and mixtures of both solvents in different catalytic processes, with the aim of decreasing the use of conventional organic solvents applied in the following catalytic reactions: homogeneous and supported rhodium catalysed asymmetric hydrogenation, biphasic palladium catalysed Suzuki C-C cross-coupling, homogeneous palladium catalysed asymmetric allylic alkylation, and ruthenium and rhodium nanoparticles catalysed arene hydrogenation were tested.
40
Wigum, Kristin Støren. "Human and ecological problem solving through radical design thinking : Analyses and development of design theory and design framework based on long-term human needs and ecological sustainable principles". Doctoral thesis, Norwegian University of Science and Technology, Department of Product Design, 2004. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-549.
Testo completo
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Anderson, Pia. "Miljöetiska perspektiv på offentlig upphandling". Thesis, Uppsala universitet, Teologiska institutionen, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-425822.
Testo completoAbstract (sommario):
There are directives for how public procurement should be conducted, in terms of quality,price, non-discrimination, transparency, equal treatment, reasonable requirements and how environmental, social and labor law considerations should be taken into account. Public procurement must also solve societal problems with the aim of achieving the global goals, but despite these guidelines, environmental ethical problems still remain for how a purchaser should prioritize and evaluate between the social, ecological and economic responsibility in public procurement. The purpose was to investigate whether environmental ethics could make a significant contribution in highlighting and understanding the environmental ethical challenges, conflicts, gaps and considerations that public procurement faces and provide answers to how public procurement should ethically value different tenders in order to be able to choose the supplier that makes the greatest social, ecological and economic benefit to society with the aim of achieving the global goals. The conclusion is that doctor Olle Torpman's environmental ethical sub-issues make the ethical challenges, as conflicts, gaps and considerations that public procurement faces visible and comprehensible. The application of the ethics of sustainable development, specified by professor Mikael Stenmark, solves the environmental ethics problems and shows that an environmental ethics theory makes a significant contribution when it comes to providing answers to how public procurement should ethically value the social, ecological and economic responsibility in public procurement. The procurement authority has been commissioned by the government to amend the law on public procurement so that it is in line with the new climate law. I hope that this thesis can provide an environmental ethical perspective on public procurement. Keywords: sustainable purchases, sustainable public procurement, environmental ethics, evaluate sustainability in purchasing, sustainable development goals, public procurement shall solve societal problems.
42
Maccaferri, Cristian. "Valorization and recycling of raw materials through a waste management system, case of study Koinonia Community, Lusaka, Zambia". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13571/.
Testo completoAbstract (sommario):
This thesis presents the implementation and the optimization of a waste management system (WMS) in the Koinonia community (that is sited in the Chilanga district near Lusaka), showing the challenges that must be faced, implementing a WMS in a developing country. In the first part of the thesis it will be contextualized the waste management in the Zambian economy showing how a diversification involving the it could fit with the needs of the Nation. In the second part it will be treated the waste management hierarchy through the illustration of some European policies (like Circular Economy Package) and best practice (like WtE in Sweden). In the third part it will be analyzed the case of study Koinonia community where it has been spent three month. The object of the study was how to make the waste management system economical sustainable, the various issue regarding this subject are described by some reports wrote at the beginning of the experience and at the end. In addition, the chapter presents a study about the waste production in Chilanga and the data collected by means the interview with the waste aggregator present in the city.
Concluding, it is showed a proposal of evolution of the waste management system which consist in install a phv (Photovoltaic) system that will feed an ecological island of low dimension.
43
Ferreira, Ana Maria da Conceição. "Ionic liquids aqueous solutions as sustainable solvents in separation processes". Doctoral thesis, 2018. http://hdl.handle.net/10773/24094.
Testo completoAbstract (sommario):
This work is focused on the development of sustainable and cost-effective solvents and separation processes, particularly by applying aqueous solutions of ionic liquids (ILs). It is shown the potential of ILs aqueous solutions as alternative solvents to extract value-added compounds from biomass, avoiding the use of the commonly applied volatile organic solvents, and their use as phase-forming components of aqueous biphasic systems (ABS) to develop reversible and/or integrated separation platforms.
In the first set of results, it is demonstrated the high performance of ILs aqueous solutions to extract caffeine and hydroxymatairesinol (HMR) from spent coffee grounds (SCG) and Norway spruce knots, respectively. In the first work it is shown the relevance of the hydrotropy concept as the major factor behind the improved extraction performance of ILs aqueous solutions, whereas in the second work biocompatible ILs were applied and proposed to be used directly with the biomass extracts in nutraceutical and cosmetic applications. Still focused on the use of ILs aqueous solutions, these were then explored in the creation of reversible aqueous biphasic systems (ABS) as alternative separation platforms, followed by the development of integrated production-separation strategies. Transitions from monophasic to biphasic regimes were shown to occur by changes in pH and temperature (applied as external stimulus). Examples on their use in the separation of mixtures of amino acids and of nucleic acids from proteins are given. Finally, it is shown the applicability of reversible ABS as integrated production-separation processes. pH-driven ABS were applied in the production of hydroxymethylfurfural (HMF) from fructose at acidic media, followed by their separation at alkaline conditions (inducing the two phases separation). On the other hand, and taking advantage of the biocompatible nature of the ABS phase-forming components, thermoreversible ABS were used in biocatalytic processes. A reaction catalysed by laccase occurs in the homogenous solution, after which small temperature changes induce the two-phase formation and the complete separation of the enzyme from the respective product. These systems also allow the recovery and reuse of the ABS phases, contributing towards the development of sustainable production and separation processes. Although additional research on these solvents and systems scale-up feasibility is still required, the results here presented unveil the relevance of IL aqueous solutions as alternative solvents and on the development of efficient separation processesEste trabalho compreende o desenvolvimento de solventes e processos de separação sustentáveis, eficientes e rentáveis, através da aplicação de soluções aquosas de líquidos iónicos (LIs). Em particular mostra-se o potencial de soluções aquosas de LIs como solventes alternativos para a extração de compostos de valor acrescentado a partir de biomassa, evitando portanto a utilização de solventes orgânicos voláteis, assim como a sua utilização na formação de sistemas aquosos bifásicos (SAB) como processos de separação. No primeiro conjunto de resultados demonstra-se que soluções aquosas de LIs apresentam uma elevada capacidade para extrair cafeína e hidroximatairesinol (HMR) de borras de café e de nós de abeto da Noruega, respetivamente. O primeiro trabalho nesta vertente mostra a importância do conceito de hidrotropia, atuando como o principal fator responsável pelo elevado desempenho das soluções aquosas de LIs na extração de compostos de valor acrescentado a partir de biomassa, enquanto que o segundo trabalho demonstra a utilização de LIs biocompatíveis, permitindo a utilização direta dos extratos de biomassa em aplicações nutracêuticas e de cosmética. As soluções aquosas de LIs também foram estudadas na criação de SAB reversíveis, como plataformas de separação alternativas, assim como no desenvolvimento de sistemas integrados de reação-separação. As respetivas transições de fase ocorrem por aplicação de estímulos externos, tais como pH e temperatura, e a sua aplicação foi demonstrada na separação de misturas de aminoácidos, e ácidos nucleicos e proteínas. Por fim, demonstra-se a utilização de SAB reversíveis como processos integrados de produção e separação. Os SAB reversíveis obtidos por alterações de pH foram aplicados na produção de hidroximetilfurfural (HMF) a partir de frutose em meio ácido, seguido da sua separação em condições alcalinas (induzindo a formação de duas fases). Por outro lado, e tirando partido da natureza biocompatível dos constituintes dos SAB, estudaram-se SAB reversíveis através da alteração da temperatura em processos biocatalíticos. A reação ocorre em meio homogéneo, catalisada pela lacase, onde pequenas alterações de temperatura induzem a formação de duas fases e a completa separação da enzima do respetivo produto. Estes sistemas permitem também a recuperação e reutilização das fases/constituintes dos SAB, contribuindo para o desenvolvimento de processos sustentáveis. Embora seja ainda necessária investigação adicional sobre a viabilidade destes solventes e sistemas para aplicação em larga escala, os resultados aqui apresentados mostram a relevância de soluções aquosas de LIs como solventes alternativos e no desenvolvimento de processos de separação
Programa Doutoral em Engenharia Química
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林躍龍. "From the perspective of sustainable development to discuss Indigenous community of eco-tourist crossfire and solvent－the example of Atayal Tribe Lunpi community, Datong Hsiang, Yilan County". Thesis, 2008. http://ndltd.ncl.edu.tw/handle/6u28km.
Testo completoAbstract (sommario):
碩士佛光大學
公共事務學系
96
Abstract The research of contemporary Taiwanese local development has been showed two topics. One is development of community tour and the other is environment maintenance. Since the 921 earthquake, government highly respected maintenance of ecological for preventing disaster due to voice of ecological conservation was up surging and The World Summit on Sustainable Development has took place in South Africa in 2002, the subject is environment and impoverishment. According to author opinion, the research of sustainable development of aborigine community ecological tour can complement each other between community and environment and help to understand change of Taiwanese community movement development. The essay is base on this subject, Lunpi community, Datong Hsiang, Yilan County as a object and exploration of ecological tour. Author initial investigated as below, from whole perspective and compare with past, aborigine community has been changed these years through community ecological tour. As ecological perspective, aborigine community foster mountains and rivers to preserve ancestors’ residence base on natural right. As economical perspective, show mode of protect fishes with seal streams and sightseeing development. Secondly, author found aborigine have benefits conflict with public for protecting community ecological environment. Aborigine has difficult position when drive community sustainable ecological tour with ecological theory. Surely, different aborigine community will modify development route automatically base on different culture conditions for hold together outward benefits and assist community development. Take Lunpi community for example, it has been established Division of Habitats and Ecosystems in Jiuliao brook firstly, not only protection of ecological interface but also convert structure of community relationship. Secondly, it has been established trakis can let tourists experience aborigine culture. It has been benefited outward network and promoted sustainable development of aborigine community. During process of amendment, let sustainable development of ecological environment of aborigine tribe has been obtained strategies.
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Santos, Maria João Martins dos. "Towards solving a robust and sustainable Vehicle Routing Problem with Backhauls". Doctoral thesis, 2020. https://hdl.handle.net/10216/129823.
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Santos, Maria João Martins dos. "Towards solving a robust and sustainable Vehicle Routing Problem with Backhauls". Tese, 2020. https://hdl.handle.net/10216/129823.
Testo completo
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Mara, Setyo Tri Windras, e Setyo Tri Windras Mara. "SOLVING A MULTI-OBJECTIVE SUSTAINABLE LOCATION-ROUTING PROBLEM USING DISCRETE MULTI-OBJECTIVE SINE-COSINE ALGORITHM". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/59r5es.
Testo completoAbstract (sommario):
碩士國立臺灣科技大學
工業管理系
107
The location-routing problem (LRP) is an emerging area in logistics research which combines two well-known distribution planning tasks: facility location problem (FLP) and vehicle routing problem (VRP). The main goal of planning a distribution network is to obtain a minimum systemwide cost, which resembles companies’ economical objective. However, in order to achieve a more sustainable future, nowadays companies have to start to give attention to the sustainability issue, such as providing workload balance for their employees and producing less emission from their operational activities. The challenge arises because sustainability issue is potentially conflicting with companies’ economical objective. Therefore, an effort has to be made to find the optimal solution. Our literature review finds only limited works in LRP which have already addressed sustainability issue comprehensively. Thus, this study intends to present a multi-objective sustainable LRP to address this issue. The proposed model considers three objective functions: (1) to minimize the total cost associated with facility, vehicle, and distribution, (2) to balance the workload in distribution activities, and (3) to minimize CO2 emission from transportation activities. The main purposes of this model are to obtain the optimal location of distribution centers, a number of vehicles established, and delivery routes which satisfy all of these three objectives. In order to solve the model, this study implements a novel metaheuristic for multi-objective routing problem, namely the multi-objective sine-cosine algorithm (MOSCA). The algorithm is modified with a simple discretization technique to deal with discrete search space. Then, the performance of the proposed algorithm is evaluated with several test instances and applied to solve a real world case study in Daerah Istimewa Yogyakarta, Indonesia. The results are compared to three classical metaheuristics, namely non-dominated sorting genetic algorithm-II (NSGA-II), multi-objective particle swarm optimization (MOPSO), and Pareto archived evolution strategy (PAES). The experimental results indicate that, based on five comparison metrics, MOSCA performs better than the other algorithms.
48
Damabi, Roya Mohebbi Pour. "Problem-solving politics : debt, discourse and the International Monetary Fund". Thesis, 2005. http://hdl.handle.net/10413/2684.
Testo completoAbstract (sommario):
This dissertation aims to problematize the concept (and proposed policy) of "debt sustainability", particularly in relation to those countries classified as "low-income", by attempting to map the logic behind what is presented as neutral, technical fact (i.e., "best practice") and seeing what work this logic does, i.e., what its effects are. Debt sustainability is not a free-floating concept, but one that is operationalized in policy. This means that the outcomes of employing a debt sustainability framework for low-income countries may have tangible consequences; in this way, and most importantly, debt sustainability may also have consequences regarding prospects for debt reliefand for the way countries and organizations make lending and borrowing decisions. The way the International Monetary Fund (IMF) conceptualizes and presents indebtedness, poverty, governance, and (sustainable) "development" dialectically reproduces a discourse around debt that both limits (depoliticizes) and opens possibilities for debt cancellation and fundamental change fundamental change in the IMF's role and function, in the Fund's relations with countries of the global south, and in the budgetary and other constraints those countries face in processes of "indebtedness" and "development".Thesis (M.A.)-University of KwaZulu-Natal, Durban, 2005.
49
Craveiro, Rita Paula Paiva. "Engineering bio-based polymers using alternative solvents and processes". Doctoral thesis, 2015. http://hdl.handle.net/10362/17121.
Testo completoAbstract (sommario):
The work presented in this thesis explores novel routes for the processing of bio-based polymers, developing a sustainable approach based on the use of alternative solvents such as supercritical carbon dioxide (scCO2), ionic liquids (ILs) and deep eutectic solvents (DES). The feasibility to produce polymeric foams via supercritical fluid (SCF) foaming, combined with these solvents was assessed, in order to replace conventional foaming techniques that use toxic and harmful solvents.
A polymer processing methodology is presented, based on SCF foaming and using scCO2 as a foaming agent. The SCF foaming of different starch based polymeric blends was performed, namely starch/poly(lactic acid) (SPLA) and starch/poly(ε-caprolactone) (SPCL). The foaming process is based on the fact that CO2 molecules can dissolve in the polymer, changing their mechanical properties and after suitable depressurization, are able to create a foamed (porous) material. In these polymer blends, CO2 presents limited solubility and in order to enhance the foaming effect, two different imidazolium based ILs (IBILs) were combined with this process, by doping the blends with IL. The use of ILs proved useful and improved the foaming effect in these starch-based polymer blends.
Infrared spectroscopy (FTIR-ATR) proved the existence of interactions between the polymer blend SPLA and ILs, which in turn diminish the forces that hold the polymeric structure. This is directly related with the ability of ILs to dissolve more CO2. This is also clear from the sorption experiments results, where the obtained apparent sorption coefficients in presence of IL are higher compared to the ones of the blend SPLA without IL.
The doping of SPCL with ILs was also performed. The foaming of the blend was achieved and resulted in porous materials with conductivity values close to the ones of pure ILs. This can open doors to applications as self-supported conductive materials.
A different type of solvents were also used in the previously presented processing method. If different applications of the bio-based polymers are envisaged, replacing ILs must be considered, especially due to the poor sustainability of some ILs and the fact that there is not a well-established toxicity profile.
In this work natural DES – NADES – were the solvents of choice. They present some advantages relatively to ILs since they are easy to produce, cheaper, biodegradable and often biocompatible, mainly due to the fact that they are composed of primary metabolites such as sugars, carboxylic acids and amino-acids. NADES were prepared and their physicochemical properties were assessed, namely the thermal behavior, conductivity, density, viscosity and polarity. With this study, it became clear that these properties can vary with the composition of NADES, as well as with their initial water content.
The use of NADES in the SCF foaming of SPCL, acting as foaming agent, was also performed and proved successful. The SPCL structure obtained after SCF foaming presented enhanced characteristics (such as porosity) when compared with the ones obtained using ILs as foaming enhancers.
DES constituted by therapeutic compounds (THEDES) were also prepared. The combination of choline chloride-mandelic acid, and menthol-ibuprofen, resulted in THEDES with thermal behavior very distinct from the one of their components. The foaming of SPCL with THEDES was successful, and the impregnation of THEDES in SPCL matrices via SCF foaming was successful, and a controlled release system was obtained in the case of menthol-ibuprofen THEDES.
50
Tai, Kuo-Kuang, e 戴國銧. "How to Perform Sustainable Management and Solve the Problems It Faces – A Distributing Company". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7svmw2.
Testo completoAbstract (sommario):
碩士國立交通大學
管理學院高階主管管理碩士學程
107
Bio-Med Industry changes for the better day by day, now with AI, IOT Big Data joining, it advances much more at a tremendous pace. Viewing the high speedy growth globally, within recent years Taiwan Bio-Med Industry have grown rapidly with satisfactory results too under the government’s encouragement using antibodies and cell to gradually cure diseases which before taken as uncured. Also, it is effective for earlier detection and curing. Based on the earlier detection of tau-protein, there makes great process. Bio-Med Industry is surely a good weapon to compete with others around the world. If integrating with IT Industry, it will create another new industry, making Taiwan with growth to top. The feature between Bio-Med distributors and normal distributors is different. Besides the normal/basic import/export knowledge, there needs much more professional training and experience, even good after-service to meet with customers’ needs. It is indeed difficult to become a Bio-Med distributor. It is hard to survive under the hard competitions, not to say to become the leading position in the field. The merge between suppliers brings serious harm to the distributors. If having no advanced protection, it is, just as mentioned, easily finished/disappeared. The risk control is a must to big scaled company, such as license, patent application, stand-by products, etc. CSB as well as other companies all think it is a density and inevitable to distributors when distributorship is terminated due to suppliers merged. While, from the course of Managing Strategy given by EMBA professors of National Chiao Tung University, I learn things may not happen like this. Trade Off is quite important, you need to decide which to keep and which to give up (As you saw, so you will reap). CSB’s transformation, with its ready priority, self-developed products, own brand, service center, etc. will be a good innovation. CSB, although lost a lot and delayed the original plan for IPO due to distributorship terminated due to suppliers merged, still fortunately learn its own current constitution. It needs adjust wholly to be realized. Then IPO creates its value. Only with this the sales growth will be not controlled by others, and have big alternation. Accordingly, it can estimate its annual business growth, and conduct IPO with its real meaning and value. Business establishing is not an easy thing, but, to manage continuously is much more difficult in competition. This essay well expresses personal experience of many years in business establishing and mainly - “How a distributing company to perform sustainable management and solve the problems it faces”. Believe it is a worthwhile reference to the new comings.