Dissertations / Theses on the topic 'Organic reducers'
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1
McDonald, Heather Brown. "The effect of sulfide inhibition and organic shock loading on anaerobic biofilm reactors treating a low-temperature, high-sulfate wastewater." Diss., University of Iowa, 2007. http://ir.uiowa.edu/etd/129.
2
Zhao, Yuxi. "Synthèse de donneurs d’électrons organiques : application en synthèse organique et chimie des polymères." Electronic Thesis or Diss., Aix-Marseille, 2021. http://www.theses.fr/2021AIXM0156.
Abstract:
Les donneurs d'électrons organiques (DEO), aux potentiels redox exceptionnellement négatifs, ont montré un intérêt particulier en synthèse organique du fait de leurs fortes propriétés réductrices. Ils sont capables de transférer spontanément un ou deux électrons à des substrats organiques, formant ainsi des intermédiaires radicalaires ou anioniques. Néanmoins, la diversité structurale des DEO est limitée et leur champ d'application assez restreint.Dans cette thèse, nous avons tout d'abord développé de nouvelles bibliothèques de DEO afin d'identifier de nouvelles familles de réducteurs organiques, d'élargir la gamme de potentiels redox et d'accéder à de nouvelles réactivités. Des modulations structurales appropriées sur sept catégories de sels d'iminium ont donné accès à de puissants DEO avec diverses capacités réductrices. Cette étude a également permis de rationaliser les facteurs régissant le transfert d’un ou deux électrons en fonction de la structure du DEO et des conditions réactionnelles. Une enquête mécanistique plus approfondie a confirmé les structures des espèces donneuses d'électrons formellement actives. Enfin, les DEO se sont également avérés être de remarquables systèmes redox organiques pour l’amorçage de réactions de polymérisation radicalaire et anionique. Alors que la propagation anionique est initiée par réduction directe du monomère, la simple addition d'un oxydant compétitif, avec un potentiel de réduction plus élevé, permet de passer à un processus de propagation radicalaire. Ces stratégies de polymérisation ont montré une excellente applicabilité pour la préparation d'une large gamme de (co-)polymères à haute valeur ajoutéeOrganic electron donors (OEDs) with exceptionally negative redox potentials have attracted considerable attention in organic synthesis as powerful reducers. They enable the spontaneous transfer of one or two electrons to organic substrates, to form radical or anionic intermediates. Nevertheless, the structural diversity of OEDs is limited and their application scope quite narrow. In this thesis, we first developed novel libraries of OEDs in order to identify new families of organic reducers, broaden the range of redox potentials and access new reducing reactivities. Appropriate structural modulations on seven categories of iminium salts gave access to powerful OED with various reducing abilities. It also allowed to rationalize the factors governing single- or double-electron transfers according to the OED structures and the reaction conditions. A more thorough mechanistic investigation was conducted to formally confirm the active electron donor species at work.Finally, OEDs also appeared to be remarkable organic redox initiating systems for both free radical and anionic polymerization reactions. While the anionic propagation was promoted by direct reduction of the monomer, simple addition of a competing oxidant with a higher reduction potential allowed to switch to a clean free radical propagation process. Scope investigation exhibited excellent applicability of these self-initiating polymerization strategies, which enabled the preparation of a large array of (co-)polymers with high added values
3
Canfield, Lesley Mary. "Microbiological transformations of partially reduced heterocycles." Thesis, University of Portsmouth, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358921.
4
Hessler, Alex G. "Reduced Tillage and Living Mulches for Organic Vegetable Production." UKnowledge, 2013. http://uknowledge.uky.edu/pss_etds/33.
Abstract:
Reduced tillage and living mulches are alternative management strategies that can improve soil quality by minimizing disturbance and building soil organic matter. Weed suppression by these two practices alone is often insufficient to avoid crop yield losses, but their performance in an integrated system is not well understood. This project investigated the production of bell pepper (Capsicum annuum L.) and dry bean (Phaseolus vulgaris L.) in conventional tillage and strip tillage with a living mulch of teff (Eragrostis tef Zucc.) and Korean lespedeza (Kummerowia stipulacea Maxim.). Yields of pepper and bean were generally higher under conventional tillage without living mulch. Weed biomass was not influenced by tillage, and was adequately suppressed by teff in a year when conditions for teff growth were favorable. Mowing appeared to suppress weed growth but not living mulch growth. Soil nitrate and ammonium concentration was generally higher under conventional tillage without living mulch. Delaying living mulch seeding by 15 days after crop establishment generally did not affect weed suppression or crop yield. Soil aggregate stability was not consistently affected by tillage or living mulch. Increased mowing frequency, living mulch planting delay, or distance between the crop row and the living mulch may be necessary to achieve acceptable yields with living mulches.
5
Chari, Tarun. "Reduced graphene oxide based transparent electrodes for organic electronic devices." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104534.
Abstract:
This thesis explores the utility of reduced graphene oxide and hybrid reduced graphene oxide/single walled carbon nanotubes as a transparent electrode. Graphene oxide was fabricated using the modified Hummers method, transferred to arbitrary substrates by a vacuum filtration method, and reduced chemically and thermally thus creating thin, large area reduced graphene oxide films. Films were characterized electrically, optically, spectroscopically, and topographically. Raman and X-ray photoelectron spectroscopy techniques were utilized to ensure successful fabrication of reduced graphene oxide. The reduced graphene oxide electrodes exhibit sheet resistances on the order of 10 – 100 kΩ/sq with transparencies between 60 – 90 %. To ameliorate these electronic properties, single walled nanotubes were introduced during the filtration process to separate the graphene oxide nanoplatelets and prevent structural deformation during reduction. This nanotube doping yielded a two-fold decrease in sheet resistance for low nanotube to graphene oxide ratios, but increased sheet resistance for higher nanotube to graphene oxide ratios. Reduced graphene oxide electrodes and nanotube/reduced graphene oxide hybrid electrodes were used in organic light emitting diode and organic solar cell applications. Organic light emitting diodes exhibited current efficiencies of about 1 cd/A and organic solar cells exhibited power conversion efficiencies less than 1 % for both reduced graphene oxide and hybrid electrodes.Cette thèse examine l'utilité de l'oxyde de graphène réduit et de l'hybride oxyde de graphène réduit et nanotubes carbone en fonction d'une utilisation comme électrode transparente. L'oxyde de graphène a été fabriqué par la méthode de Hummers modifié puis a été transféré sur un substrat arbitraire par la méthode de filtration avec suction à vide, et a été réduit chimiquement et thermiquement pour créer des feuilles d'oxyde de graphène réduit qui sont minces et qui couvrent une grande surface. Les feuilles ont été caractérisées par des mesures électriques, optiques, spectroscopiques, et topographiques. Les spectroscopies Raman et par photoélectron induits par rayons-X ont été utilisées pour s'assurer que la fabrication de l'oxyde de graphène reduit a été obtenue. Les électrodes d'oxyde de graphène reduit montrent des résistances de feuille de 10– 100 kΩ/sq avec des transparences entre 60 – 90 %. Pour améliorer ces propriétés, des nanotube de carbone monoparois ont été introduits pendant le processus de filtration pour séparer les nanoplatelets d'oxyde de graphène et pour éviter la déformation structurelle pendant la processus de réduction. Ce dopage de nanotubes a diminué la résistance de feuille par un facteur deux pour des proportion faibles de nanotubes avec l'oxyde de graphène, mais a augmenté la resistance pour les hautes proportions. Les électrodes d'oxyde de graphène reduit et les électrodes hybrides nanotubes/oxyde de graphène reduit ont été utilisées dans des dispositifs optoélectroniques organiques; spécialement des diodes électroluminescentes et des cellules solaires. Les diodes électroluminescentes organiques ont des rendements de courant inferieurs à 1 cd/A et les cellules solaire ont des rendements de puissance inferieurs à 1 % pour les deux types d'életrodes: oxyde de graphène réduit et hybrides.
6
Hillis, Jeffrey Jackson. "Polychlorinated biphenyl exposure reduces reproductive performance of male bluegills (Lepomis macrochirus)." OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1347.
Abstract:
Endocrine disrupting chemicals in wild animals, including fish, can disrupt reproduction by causing intersexuality. Organic pollutants, specifically polychlorinated biphenyls (PCBs), have been shown to be estrogenic or anti-androgenic likely contributing to intersexuality in males. Organic pollutants persist in the environment despite being restricted for use in the United States. Bluegills, Lepomis macrochirus, play a crucial role in lake food webs as forage and sport fish and may be affected by PCBs. In the current study, male bluegills collected in 2010 from selected Illinois lakes were analyzed to quantify PCB body residues and the incidence of intersexuality (n=200). Experiments were then conducted in 2011 and 2012 to assess the reproductive output of mature males with varying PCB body residues paired with mature females containing no detectable PCB body residues held in uncontaminated 0.05-hectare research ponds (Southern Illinois University Touch of Nature Pond Facility). Lake-specific male bluegill whole-body tissue PCB body residues ranged from below reporting limit to 2 mg/kg dry weight (non-lipid normalized basis) and varied significantly among lakes (F7,32= 9.59, p<0.0001). No male intersex bluegills were found. In both reproductive experiments, abundance of young declined as male PCB body residues increased (F 4,18 = 13.28; P=0.002). Adult survival was unrelated to reproductive output. Taken together, these results suggest PCBs, which are ubiquitous in aquatic and terrestrial habitats, have the ability to alter male reproductive performance, and possibly population dynamics and community structure through reduced recruitment, in the absence of overt intersexuality.
7
Chen, Sen. "Reduced Organic Sulfur: Analyisis and Interaction with Mercury in the Aquatic Environment." FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/442.
Abstract:
Reduced organic sulfur (ROS) compounds are environmentally ubiquitous and play an important role in sulfur cycling as well as in biogeochemical cycles of toxic metals, in particular mercury. Development of effective methods for analysis of ROS in environmental samples and investigations on the interactions of ROS with mercury are critical for understanding the role of ROS in mercury cycling, yet both of which are poorly studied.
Covalent affinity chromatography-based methods were attempted for analysis of ROS in environmental water samples. A method was developed for analysis of environmental thiols, by preconcentration using affinity covalent chromatographic column or solid phase extraction, followed by releasing of thiols from the thiopropyl sepharose gel using TCEP and analysis using HPLC-UV or HPLC-FL. Under the optimized conditions, the detection limits of the method using HPLC-FL detection were 0.45 and 0.36 nM for Cys and GSH, respectively. Our results suggest that covalent affinity methods are efficient for thiol enrichment and interference elimination, demonstrating their promising applications in developing a sensitive, reliable, and useful technique for thiol analysis in environmental water samples.
The dissolution of mercury sulfide (HgS) in the presence of ROS and dissolved organic matter (DOM) was investigated, by quantifying the effects of ROS on HgS dissolution and determining the speciation of the mercury released from ROS-induced HgS dissolution. It was observed that the presence of small ROS (e.g., Cys and GSH) and large molecule DOM, in particular at high concentrations, could significantly enhance the dissolution of HgS. The dissolved Hg during HgS dissolution determined using the conventional 0.22 µm cutoff method could include colloidal Hg (e.g., HgS colloids) and truly dissolved Hg (e.g., Hg-ROS complexes). A centrifugal filtration method (with 3 kDa MWCO) was employed to characterize the speciation and reactivity of the Hg released during ROS-enhanced HgS dissolution. The presence of small ROS could produce a considerable fraction (about 40% of total mercury in the solution) of truly dissolved mercury (< 3 kDa), probably due to the formation of Hg-Cys or Hg-GSH complexes. The truly dissolved Hg formed during GSH- or Cys-enhanced HgS dissolution was directly reducible (100% for GSH and 40% for Cys) by stannous chloride, demonstrating its potential role in Hg transformation and bioaccumulation.
8
McAdams, Brandon C. "Relationships between reduced sulfur and dissolved organic matter in prairie pothole wetlands." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1493627284045985.
9
ALRASHED, MAHER M. "ORGANIC/INORGANIC HYBRID COATINGS FOR ANTICORROSION APPLICATIONS." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1491226580793534.
10
Dcunha, Ruhee Lancelot. "Towards an Improved Method for the Prediction of Linear Response Properties of Small Organic Molecules." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104677.
Abstract:
Quantum chemical methods to predict experimental chiroptical properties by solving the time-dependent Schrödinger equation are useful in the assignment of absolute configurations. Chiroptical properties, being very sensitive to the electronic structure of the system, require highly-accurate methods on the one hand and on the other, need to be able to be computed with limited computational resources.
The calculation of the optical rotation in the solution phase is complicated by solvent effects. In order to capture those solvent effects, we present a study that uses conformational averaging and time-dependent density functional theory calculations that incorporate solvent molecules explicitly in the quantum mechanical region. While considering several controllable parameters along which the system's optical rotation varies, we find that the sampling of the dynamical trajectory and the density functional chosen have the largest impact on the value of the rotation.
In order to eliminate the arbitrariness of the choice of density functional, we would prefer to use coupled cluster theory, a robust and systematically improvable method. However, the high-order polynomial scaling of coupled cluster theory makes it intractable for numerous large calculations, including the conformational averaging required for optical rotation calculations in solution. We therefore attempt to reduce the scaling of a linear response coupled cluster singles and doubles (LR-CCSD) calculation via a perturbed pair natural orbital (PNO++) local correlation approach which uses an orbital space created using a perturbed density matrix. We find that by creating a "combined PNO++" space, incorporating a set of orbitals from the unperturbed pair natural orbital (PNO) space into the PNO++ space, we can obtain well-behaved convergence behavior for both CCSD correlation energies and linear response properties, including dynamic polarizabilities and optical rotations, for the small systems considered.
The PNO++ and combined PNO++ methods require aggressive truncation to keep the computational cost low, due to an expensive two-electron integral transformation at the beginning of the calculation. We apply the methods to larger systems than previously studied and refine them for more aggressive truncation by exploring an alternative form of the perturbed density and a perturbation-including weak pair approximation.Doctor of Philosophy
Theoretical chemistry attempts to provide connections between the structure of molecules and their observable properties. One such family of observables are chiroptical properties, or the effect of the medium on the light which passes through it. These properties include the scattering, absorption and change in polarization of light. Light being classically an electromagnetic field, chiroptical properties can be derived by treating molecules quantum mechanically and the light classically. The prediction of chiroptical properties on computers using the principles of quantum mechanics is still a growing field, being very sensitive to the method used, and requiring considerations of factors such as conformations and anharmonic corrections. Matching experimental properties is an important step in the creation of a reliable method of predicting properties of systems in order to provide more information than can be obtained through experimental observation. This work begins by addressing the problem of matching experimentally obtained quantities. Our results show that current time-intensive methods still fall short in the matching of experimental data. Thus, we then move on to approximating a more robust but computationally expensive method in order to be able to use a more accurate method on a larger scale than is currently possible. On obtaining positive results for small test systems, we test the new method on larger systems, and explore possible improvements to its accuracy and efficiency.
11
Semple, Adelaide Mary. "Nitrogen balance and changes in soil nutrients in reduced inputs systems of cropping." Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284399.
12
Palian, Michael. "Glycopeptide enkephalin analogs: Design, synthesis, biophysical and pharmacological evaluation of potent analgesics with reduced side-effects." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/280097.
Abstract:
Pain relief is one of the most fundamental, yet elusive goals of medicine. In the mammalian brain, one means of pain suppression is through activation of the opioid receptors. The opioids themselves are a broad class of centrally acting ligands that may target the delta, kappa, and/or mu opioid receptors in the brain or the spinal column in order to produce pain relief. Glycopeptides have been shown to be versatile, non-toxic alternatives to morphine-induced analgesia in mice. In order to further explore the limits of glycopeptide analgesics, we have synthesized three series of glycopeptide enkephalin analogues (linear glycopeptides, lipo-glycopeptides, and amphipathic alpha-helical glycopeptides) in order to explore the pharmacology and glycopeptide-membrane interactions associated with high-affinity receptor agonism. The three classes of compounds were designed to interact with the cellular membrane to a different degree, and in varying modes of action. Each class of compounds has presented different challenges, but display diverse in vitro and in vivo profiles. Overall, the glycopeptides have shown excellent potential as advanced drug candidates. Total synthesis, circular dichroism, 2-D NMR, molecular modeling, membrane interaction, in vitro binding, in vivo analgesia and dependence liability studies have been performed and will be discussed.
13
STEFANINI, NICOLA. "Optimization of Industrial Polymeric Products to Improve Quality and Reduce Environmental Impact." Doctoral thesis, Università degli Studi di Camerino, 2019. http://hdl.handle.net/11581/428907.
Abstract:
The present thesis is the result of three years’ collaboration between the University of Camerino and ELANTAS Europe Srl. The strong collaboration between university and companies allows to students like others and me to do research with an industrial approach, facing with the problematics of working life.
The work was carried out among the laboratory of Organic Chemistry of Prof. Enrico Marcantoni at the University of Camerino (Camerino, Italy), the R&D laboratory of ELANTAS Europe in Ascoli Piceno (Italy) and the R&D laboratory of ELANTAS PDG INC in Saint Louis (Missouri, USA).
The thesis concern the environmental impact of some industrial polymeric materials. Polymeric materials are very important in modern society: they have considerable advantages over products of other origins with lower costs with the same performance. Nevertheless, they allow some applications that some years ago would have been unthinkable (microencapsulation, shape memory materials, and many others).
At the same time, environmental impact is a crucial topic strictly linked to polymeric materials (as all others materials), and to the period we are living. The production of such materials is constantly growing, exceeding the production of many others materials, and it is becoming increasingly important to find ways to produce them more efficiently and to recover waste products. The consequences of a production without limitation and control could be catastrophic for the whole world and humankind too.
During my PhD, I worked on three industrial products in order to reduce their environmental impact, keeping their physical properties unchanged.
After a first general introduction on polymeric materials, their uses, and their production, the second chapter concern about improving a recovery process for waste PMMA. The study allowed identifying undesirable by-products formed during the thermal depolymerization of PMMA and removing them in the consequent re-polymerization by an innovative dissolution/re-precipitation method.
The third and fourth chapters deal with two coatings for wires electrical insulation, one based on polyurethanes (PU) and the other on polyesterimides (PEI). With the PU-based one, the target was to reduce the amount of loss material during the application stage and to increase the speed of application in order to reduce the energy consumption of the process. Whereas with the PEI-based enamel the purpose was to synthesized a solvent-free product using a twin-screw extruder and using recycled PET as alternative raw material to form the polyester part. The extruder technology is less energy consuming compare to the batches ones and allows working without solvents, since it can work with high viscosity materials. Moreover, the extruded product, with an additional system, can be potentially applied onto the wire with a higher thickness compare to the respective solventbased product, allowing a greater flow of current along the wire, thus improving the performance of the finished products (i.e. reducing the charging time of electrical motors).
14
Bhowmik, Arnab. "Greenhouse Gas Emissions and Soil Quality in Long-Term Integrated and Reduced Tillage Organic Systems." Diss., North Dakota State University, 2016. http://hdl.handle.net/10365/25731.
Abstract:
Organic agroecosystems ?rely on ecological processes, biodiversity and cycles adapted to local conditions". Soil health is ?the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans? and can be used to assess agroecosystems. The fertility of organic agroecosystems is dependent upon soil organic matter, an indicator of soil health that supplies much of the nitrogen (N) and carbon (C) in soil. Despite the potential to use soil health as a dynamic measure few data sets compare soil health of different organic systems. My research compares the effects of climate and key best management practices (disturbance, amendment type, and livestock integration) on C sequestration, N cycling and greenhouse gas (GHG) emissions in five organic cropping systems. The data also contribute to our understanding of how microbial community members controlling reactive N (nitrate, nitrous oxide) and C cycling contribute to or reduce GHG as well as the potential of reduced tillage organic systems to lower GHG emissions when N is coupled with C in organic materials. This dissertation research verifies that the types and quantities of N cycling microorganisms can be used as indicators of soil health to assess the impact of short and long-term management on biogeochemical processes (the transformation and cycling of elements between non-living and living matter) that reduce or contribute to global climate change in long-term organic systems. A reduction in GHG emissions benefits the public and may increase the value added of certified organic foods.Organic Transitions Competitive (Grant no. 2011-51106-20659) from the United States Department of Agriculture (USDA)
National Institute of Food and Agriculture (NIFA)
15
Garcia, Indiana. "Removal of Natural Organic Matter to reduce the presence of Trihalomethanes in drinking water." Doctoral thesis, KTH, Kemisk apparatteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-29759.
Abstract:
In countries located in tropical zones, a critical task in drinking water plants is the removal of the natural organic matter (NOM), particularly during the rainy season when a lot of organic matter is transported by run-off into the water bodies. It provokes overloaded in the plants and they have often needed to be shut down. In the dry season, the NOM removal is also difficult due to its low concentration, and greater coagulant dosages are needed to destabilize the negative charge of the NOM. In order to increase the NOM removal, synthetic polymers based on acrylamide are sometimes used as coagulant aids. However, they have been associated with Alzheimerand are carcinogenic. Therefore, the present requirement is to find new treatments affordable for the conditions existing in tropical countries. The application of green compounds has become a responsibility to guarantee the health of the population. The situation in Nicaragua is similar to that in many tropical countries. At present, there are ten drinking water plants which use conventional treatment. Nine of them use surface water supplied by rivers, and one uses water from a lake. Many of these plants have problems of continuity, quantity, water quality, and coverage, although the water cost is low. The removal of natural organic matter by conventional or enhanced coagulation using aluminium sulphate or chitosan as coagulant while reducing the formation of trihalomethanes (THM) was the aim of this work. Chitosan is an environment-friendly compound that can act as coagulant, flocculant and adsorbent. Adsorption with activated carbon and chitosan has also been studied. The natural organic matter in the source waters was fractionated in order to determine which fractions are removed more easily by coagulation and which are recalcitrant. The experimental works was carried out with a period of sampling between 2003 and 2010, taking into consideration the dry and rainy seasons. The results show that conventional coagulation with aluminium sulphate is not sufficient to reduce the presenceof NOM sufficiently to avoid a high level of THM in the disinfection step. The NOM removal is greatly improved by treatment with enhanced coagulation, but a significant amount of NOM is not removed, with a high THM concentration as a consequence. High NOM removal can however be achieved by enhanced coagulation and subsequent adsorption with granular activated carbon. Chitosan has good properties as a coagulant in water with a high NOM content and performs well as flocculant. It also has a high adsorption capacity for NOM. Therefore, chitosan could be a good option as a substitute for aluminium sulphate compounds. However, since chitosan does not work properly in the dry season, when the NOM content is low, the use of aluminium sulphate in combination with chitosan should bestudied in more detail. A field with a large potential is the modification of the chitosan structure to increase its capacity for NOM removal and decrease the need for aluminium sulphate. Another advantage of using chitosan is the reduction of the negative impact of shrimp and squat lobster shells on the environment.QC 20110215
16
Wu, Zhibin, Xingzhong Yuan, Hua Zhong, Hou Wang, Guangming Zeng, Xiaohong Chen, Hui Wang, Lei zhang, and Jianguang Shao. "Enhanced adsorptive removal of p-nitrophenol from water by aluminum metal–organic framework/reduced graphene oxide composite." NATURE PUBLISHING GROUP, 2016. http://hdl.handle.net/10150/614746.
Abstract:
In this study, the composite of aluminum metal-organic framework MIL-68(Al) and reduced graphene oxide (MA/RG) was synthesized via a one-step solvothermal method, and their performances for pnitrophenol (PNP) adsorption from aqueous solution were systematically investigated. The introduction of reduced graphene oxide (RG) into MIL-68(Al) (MA) significantly changes the morphologies of the MA and increases the surface area. The MA/RG-15% prepared at RG-to-MA mass ratio of 15% shows a PNP uptake rate 64% and 123% higher than MIL-68(Al) and reduced graphene oxide (RG), respectively. The hydrogen bond and pi-pi dispersion were considered to be the major driving force for the spontaneous and endothermic adsorption process for PNP removal. The adsorption kinetics, which was controlled by film-diffusion and intra-particle diffusion, was greatly influenced by solution pH, ionic strength, temperature and initial PNP concentration. The adsorption kinetics and isotherms can be well delineated using pseudo-second-order and Langmuir equations, respectively. The presence of phenol or isomeric nitrophenols in the solution had minimal influence on PNP adsorption by reusable MA/RG composite.
17
Sass, Danielle. "Nano silver-Iron-reduced graphene oxide modified titanium dioxide photocatalyst for the remediation of Organic dye in water systems." University of the Western Cape, 2018. http://hdl.handle.net/11394/6274.
Abstract:
Magister Scientiae - MSc (Chemistry)Drinking water with high concentrations of inorganic and organic contaminants can cause adverse health defects. Specifically methyl orange dye is an organic water contaminant that has been known (along with others like methyl blue etc.) to have an increase in our water systems over the past few years due to increasing demand in industrial processes. It is therefore of utmost importance to remediate organic contaminants and ultimately enable prevention. The contaminants can be removed by photocatalysis. Anatase TiO2 is known for its photocatalytic degradation of environmental pollutants and photoelectro-chemical conversion of solar energy. However its application is limited since it is a wide band gap semiconductor, (Eg = 3.2 eV). The following study deals with the enhancement of the photocatalytic properties of TiO2 for remediation of organic water contaminants. The study was carried out to produce the two nanocomposites AgFe-TiO2 and AgFe-TiO2-rGO photocatalyst which purpose is to be cheap and easy to apply, with improved (fast and effective) photocatalytic degradation of methyl orange. The main objective was to decrease the band gap and to introduce intra-band gap states to absorb visible light. Modification of the TiO2 with small bandgap semiconductor, graphene and Ag- Fe nanoalloy reduced the bandgap energy for visible light absorption and photocatalytic degradation of methyl orange dye. The two composites were synthesised using sonication and chemical synthesis methods. A photocatalytic study (degradation of methyl orange dye) was carried out using a system incorporating an UV lamp source to determine the degradation of methyl orange catalysed by the synthesised photocatalysts AgFe-TiO2-rGO and AgFe-TiO2 along with UV-vis Spectroscopy. Morphological studies were carried out using HRSEM and HRTEM which determined the spherical agglomerated nature of AgFe-TiO2 and the sheet-like nature of AgFe-TiO2-rGO containing spherical agglomerants but that also contained pockets formed by the sheets of the rGO. XRD served as confirmation of the phase of TiO2 in both composites to be anatase. Analysis confirmed the formation and elemental determination of both composites. It was observed that the Band gap of TiO2 degussa decreased from 2.94 eV to 2.77 eV in the composite AgFe-TiO2. The photocatalytic reactivity of AgFe- TiO2 was an improvement from TiO2 and AgFe-TiO2-rGO based on the photocatalytic study. Therefore concluding that AgFe-TiO2 was the best catalyst to convert the dye (Orange II) into free radicals and ultimately remove the contaminant from the water compared to AgFe-TiO2-rGO.
18
Sass, Danielle Thandi. "Nano silver-iron-reduced graphene oxide modified titanium dioxide photocatalyst for the remediation of organic dye in water systems." University of the Western Cape, 2018. http://hdl.handle.net/11394/6410.
Abstract:
Magister Scientiae - MSc (Chemistry)Drinking water with high concentrations of inorganic and organic contaminants can cause adverse health defects. Specifically methyl orange dye is an organic water contaminant that has been known (along with others like methyl blue etc.) to have an increase in our water systems over the past few years due to increasing demand in industrial processes. It is therefore of utmost importance to remediate organic contaminants and ultimately enable prevention. The contaminants can be removed by photocatalysis. Anatase TiO2 is known for its photocatalytic degradation of environmental pollutants and photoelectro-chemical conversion of solar energy. However its application is limited since it is a wide band gap semiconductor, (Eg = 3.2 eV). The following study deals with the enhancement of the photocatalytic properties of TiO2 for remediation of organic water contaminants.
2021-12-31
19
Zhao, Simin. "The effects of organic ligands on biotic oxidation of structural Fe(II) in reduced nontronite by Pseudogulbenkianiasp. strain 2002." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1556873530093781.
20
Aher, Ashish. "SYNTHESIS, CHARACTERIZATION AND APPLICATIONS OF REDUCED GRAPHENE OXIDE AND COMPOSITE MEMBRANES FOR SELECTIVE SEPARATIONS AND REMOVAL OF ORGANIC CONTAMINANTS." UKnowledge, 2019. https://uknowledge.uky.edu/cme_etds/111.
Abstract:
Among the next generation materials being investigated for membrane development, partially reduced Graphene Oxide (rGO) has received increasing attention from the membrane community. rGO-based nanofiltration membranes have shown promising results in applications such as partial desalination, organic contaminant removal, gas-phase separations, and separations from solvent media. rGO offers a unique platform compared to common polymeric membranes since it can be used for separation applications in both aqueous and organic solvent media. An rGO-based platform could also be utilized to synthesize reactive membranes, giving rGO membranes the additional capability of reactively removing organic contaminants. This research focuses on the synthesis of rGO and nanocomposite membranes for applications including the separation of high-value phenolic compounds from a solvent-water mixture, removal of organic contaminants, and treatment of refinery wastewater.
First, the behavior of a rGO membrane in water and isopropanol was investigated along with its ability to separate high-value, lignin-derived oligomeric compounds from a solvent-water mixture. This study revealed the formation of stable sorbates of water in the GO channels that resulted in declined membrane permeance and improved size-exclusion cutoff. Through controlled reduction of GO by heat treatment, it was demonstrated that physicochemical properties of the GO membrane could be modulated and separation performance tuned based on the extent of reduction. A varying degree of interlayer spacing was attained between the GO laminates by controlling the O/C ratio of GO. This allowed the rGO membrane to achieve tunable molecular separation of lignin-derived model oligomeric compounds from a solvent-water mixture.
Second, the mechanism of ionic transport through the rGO membrane was studied as well as its application in partial desalination and removal of persistent organic contaminants from water. Through comprehensive experimental investigations and mathematical analysis, along with the aid of the extended Nernst Planck equation, the impacts of steric hindrance and charge interactions on the underlying ion transport mechanism were quantified. Charge interactions were observed to be the dominant exclusion mechanism for the rGO membranes. The application of rGO membranes for treatment of high TDS produced water was investigated with the goal of partial hardness and dissolved oil removal. In addition, this study demonstrated the removal of emerging organic contaminants, specifically perfluorooctanoic acid, by rGO membranes and elucidated a charge interaction-dominated exclusion mechanism for this contaminant, as well.
Finally, rGO-based and microporous polyvinylidene fluoride (PVDF)-based catalytic membrane platforms were synthesized for removal of organic contaminants via an oxidative pathway. Herein, an advanced oxidation process was integrated with membrane technology by the in-situ synthesis of Fe-based nanoparticles. The unique capability to oxidatively remove contaminants in a continuous mode of operation was explored in addition to the separation performance of the membrane. The rGO-based platform achieved high oxidative removal of trichloroethylene via a sulfate-free, radical-mediated pathway, while simultaneously removing humic acids from water and potentially eliminating undesired side reactions. A PVDF-based microporous catalytic membrane platform was shown to effectively remove organic impurities, such as Naphthenic acids, from high TDS produced water by the same pathway. The enhancement of reaction extent for elevated temperatures and longer residence times was also quantified in this study.
These studies benefit the membrane community in the following ways: 1) The work identifies the critical role of the physicochemical properties of GO, such as the O/C ratio and water sorption, for determining the permeability-selectivity of rGO membranes for solvent nanofiltration. 2) Investigations of ion transport through rGO membranes led to an understanding of a charge-dominated separation mechanism for ion retention. The Nernst-Planck equation-based approach employed in this study would enable further assessment and comparison of rGO membranes under a wide set of parameters. 3) Catalytic membrane platforms (rGO and microporous PVDF-based) were synthesized for conducting advanced oxidation reactions in the porous membrane domain, demonstrating potential applications in environmental remediation of organic contaminants.
21
Raue, Judith Doris. "Recycled organic products to reduce the negative impact of salinity and sodicity on acidic soil properties and plant growth." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/20652/1/Judith_Raue_Thesis.pdf.
Abstract:
Salt affected soils and their effects on land and water resources have been identified as one of the most severe environmental problems facing Australia. This current study focused on the incorporation of recycled organic products (RO) into an acidic saline soil that had been irrigated with an industrial effluent (IE), specifically to investigate the potential for these organics to be used in rehabilitation. Compost incorporated into the acidic saline soil was able to raise pH to more favourable levels required for plant growth (pH 6 – 7.5). Plant growth was however dependent on the input material of the compost as well as the irrigation scheme. The soils amended with this compost generally showed higher and more rapid microbial activity, measured by CO2 emissions, in all amendment rates than the plant derived compost. Overall it could be concluded that the application of RO on saline soils improved the establishment and growth of plants and alleviated to some degree the negative effects of IE. However great care should be taken at the selection of the input material, as high rates of ammonium, calcium and other soluble salts can increase the EC of an amended soil further.
22
Raue, Judith Doris. "Recycled organic products to reduce the negative impact of salinity and sodicity on acidic soil properties and plant growth." Queensland University of Technology, 2008. http://eprints.qut.edu.au/20652/.
Abstract:
Salt affected soils and their effects on land and water resources have been identified as one of the most severe environmental problems facing Australia. This current study focused on the incorporation of recycled organic products (RO) into an acidic saline soil that had been irrigated with an industrial effluent (IE), specifically to investigate the potential for these organics to be used in rehabilitation. Compost incorporated into the acidic saline soil was able to raise pH to more favourable levels required for plant growth (pH 6 – 7.5). Plant growth was however dependent on the input material of the compost as well as the irrigation scheme. The soils amended with this compost generally showed higher and more rapid microbial activity, measured by CO2 emissions, in all amendment rates than the plant derived compost. Overall it could be concluded that the application of RO on saline soils improved the establishment and growth of plants and alleviated to some degree the negative effects of IE. However great care should be taken at the selection of the input material, as high rates of ammonium, calcium and other soluble salts can increase the EC of an amended soil further.
23
Radford, Michael T. "A study of Central Florida nonroad VOC and NOx emissions and potential actions to reduce emissions." Orlando, Fla. : University of Central Florida, 2009. http://purl.fcla.edu/fcla/etd/CFE0002850.
24
Besold, Johannes [Verfasser], and Britta [Akademischer Betreuer] Planer-Friedrich. "Influences of Reduced Sulfur on Arsenic and Antimony Mobility and Binding to Natural Organic Matter / Johannes Besold ; Betreuer: Britta Planer-Friedrich." Bayreuth : Universität Bayreuth, 2020. http://d-nb.info/1218596236/34.
25
Warby, Richard Ashley Frank. "The chemical response of surface waters and organic soils across the northeastern United States, following reduced inputs of acidic deposition 1984-2001 /." Related electronic resource:, 2007. http://proquest.umi.com/pqdweb?did=1342747271&sid=1&Fmt=2&clientId=3739&RQT=309&VName=PQD.
26
Wolfe, Matthew Lee. "The effect of reduced levels of inorganic and organic trace mineral supplementation on performance, carcass traits, and fecal excretion of grow-finish swine." [Ames, Iowa : Iowa State University], 2006.
27
Burdsall, Adam C. "Abiotic Reduction Transformations of Recalcitrant Chlorinated Methanes, Chlorinated Ethanes, and 2,4-Dinitroanisole By Reduced Iron Oxides at Bench-Scale." Wright State University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=wright1527263758253055.
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Silva, Thiago Franchi Pereira da 1978. "Aplicação de nanoestruturas de carbono em células solares orgânicas e inorgânicas = Application of carbon nanostructures in organic and inorganic solar cells." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261195.
Abstract:
Orientadores: Vitor Baranauskas, Helder José CeragioliTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-27T01:34:46Z (GMT). No. of bitstreams: 1 Silva_ThiagoFranchiPereirada_D.pdf: 9373432 bytes, checksum: 13a36b35d789088396a134f65246b3a9 (MD5) Previous issue date: 2015
Resumo: Células solares orgânicas e inorgânicas representam uma excelente alternativa como fonte de energia renovável. Este trabalho consiste em aplicar nanoestruturas de carbono obtidas pela técnica HFCVD (Hot Filament Chemical Vapour Deposition) como componentes utilizados na construção e melhoria de células solares orgânicas (organic photovoltaics - OPVs) e células sensibilizadas por corante (dye-sensitized cells - DSCs). Foi obtido óxido de grafeno reduzido (rGO), carbono tipo diamante (DLC - diamondlike carbon) e diamante condutor nanoestruturado. Estes materiais foram caracterizados por microscopia eletrônica de varredura (SEM-FEG), microscopia de transmissão de alta resolução (HRTEM), espectroscopia Raman e análise termogravimétrica (TGA). O rGO foi empregado na construção das células DSC misturado na pasta de TiO2 em diferentes concentrações, produzindo o aumento de fotocorrente gerada e, consequentemente, o rendimento. O mesmo material foi empregado nas OPVs, em diferentes concentrações, para a substituição do fulereno PCBM (1-(3-metoxicarbonil)-propil-1-1-fenil- (6,6)metanofulereno) e também em conjunto com o fulereno, sendo observada também a melhoria no desempenho dos dispositivos em função da concentração. Com finalidade de substituir os contraeletrodos das células DSC, carbono tipo diamante foi depositado em substrato de alumínio (Al) e diamante condutor nanoestruturado depositado em substratos de nióbio (Nb). As células com contraeletrodos de Al com filme de DLC apresentaram sensibilidade à luz, com possibilidade de aplicação em sensores ópticos, enquanto as células com contraeletrodos de Nb com filme de diamante condutor apresentaram excelente desempenho, tornando possível a substituição dos contraeletrodos de platina
Abstract: Organic and inorganic solar cells comprise a promising solution as a renewable energy source. This work consists of applying carbon nanostructures obtained by HFCVD technique (Hot Filament Chemical Vapour Deposition) as components used in the construction and improvement of organic solar cells (organic photovoltaics - OPVs) and dye sensitized cells (dye-sensitized cells - DSCs). Reduced graphene oxide (rGO), carbon diamond-like (DLC - diamond- like carbon) and nanostructured conductor diamond was obtained. These materials were characterized by scanning electron microscopy (SEM-FEG), high resolution transmission microscopy (HRTEM), Raman spectroscopy and thermal gravimetric analysis (TGA). Reduced graphene oxide was used for the construction of the DSC cell at the TiO2 layer mixed in different concentrations, producing an increase in photocurrent generated and thus conversion efficiency. The same material was used in the OPVs at different concentrations for the replacement of fullerene PCBM (1- (3-methoxycarbonyl) -propyl-1-1-phenyl- (6,6) metanofulereno) and with the fullerene was also observed improvement in performance of the devices as a function of concentration. With aim of replacing the counterelectrode of DSCs cells, diamond-like carbon was deposited on aluminum substrate (Al) and nanostructured conductive diamond deposited on niobium (Nb) substrates. Cells with Al/DLC counterelectrode showed sensitivity to light, with the possibility of application in optical devices while cells with Nb/nanostructured conductive diamond counterelectrode showed excellent performance, with possibility to replace platinum counterelectrodes
Doutorado
Eletrônica, Microeletrônica e Optoeletrônica
Doutor em Engenharia Elétrica
29
Monteza, Sandoval Jhonatan Alexander. "Propuesta de instalación de una planta procesadora de superfoods en la empresa Liking Organic Foods SAC para reducir las pérdidas económicas generados por la tercerización." Bachelor's thesis, Universidad Católica Santo Toribio de Mogrovejo, 2020. http://hdl.handle.net/20.500.12423/3084.
Abstract:
El presente proyecto de investigación se centra en la empresa Liking Organic Foods SAC la cual ofrece productos conocidos con el nombre Superfoods tales como deshidratados y harinas. Actualmente, dicha empresa no cuenta con una planta procesadora siendo así tercerizada la producción. Esto ha generado ciertos problemas a la empresa, así mismo pérdidas económicas, las ocurrencias de mayor importancia son: demanda no atendida, demoras de entrega de productos y rechazo o retornos de los productos.
Por lo tanto, se realizó la búsqueda de antecedentes, materiales y métodos. La demanda del proyecto se determinó mediante la proyección de esta con datos históricos abarcando el 5% y 8% en frutas deshidratadas y harinas respectivamente más la cantidad que se vende actualmente.
Se diseñó la planta procesadora con un área de 948 m ubicada en el Parque Industrial Infantas Los Olivos del departamento de Lima el cual tendrá una capacidad de diseño de 50 713 unidades al año.
Se realizó una evaluación económica y financiera con una inversión de S/3 474 529,48; un TMAR de 12,90%, el TIR de 35,84% y un VAN de S/ 1 774 326,92; una relación de beneficio/costo de 1,40 y un período de recuperación de 2 años 5 meses y 23 días, siendo un proyecto viable y rentable permitiendo así a la empresa aumentar su rentabilidad en un 24,17% y reducir sus pérdidas económicas generados por la tercerización en un 24,6% en un plazo de 5 años.
30
Zhu, Yan. "TRANSMISSION ELECTRON MICROSCOPY AND FLOW FIELD-FLOW FRACTIONATION: EXPLORATION OF THE NANOSCOPIC COMPONENTS IN PARTIALLY REDUCED POLYOXOMOLYBDATES BY KINETIC PRECIPITATION WITH DE NOVO ORGANIC MOLECULES." Lexington, Ky. : [University of Kentucky Libraries], 2003. http://lib.uky.edu/ETD/ukychem2003d00119/YanZhuPHDthesis.pdf.
Abstract:
Thesis (Ph. D.)--University of Kentucky, 2003.Title from document title page (viewed June 30, 2004). Document formatted into pages; contains xv, 150 p. : ill. Includes abstract and vita. Includes bibliographical references (p. 140-148).
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Unthan, Simon Verfasser], Wolfgang [Akademischer Betreuer] Wiechert, and Jochen [Akademischer Betreuer] [Büchs. "Robot-assisted phenotyping of genome-reduced Corynebacterium glutamicum strain libraries to draft a chassis organism / Simon Unthan ; Wolfgang Wiechert, Jochen Büchs." Aachen : Universitätsbibliothek der RWTH Aachen, 2016. http://d-nb.info/1129876004/34.
32
Unda, Rodrigo Jesús, and Duarte Sebastián Zamora. "Modelo de Estandarización de Procesos aplicando herramientas Lean para reducir tiempos improductivos en las MYPES productoras de uva orgánica." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/654553.
Abstract:
El presente artículo de investigación desea poner en conocimiento al lector, la baja productividad existente en la producción de alimentos orgánicos; este estudio, se enfocará específicamente en la producción de uva. El análisis e información recabada en el sector de la agricultura orgánica, ha permitido descifrar que esta problemática surge a raíz de los tiempos improductivos que se originan en cada fase de la producción de uva orgánica, generando sobrecostos innecesarios, a ello se le suma la inexistencia de procedimientos que deberán seguirse para mantener una producción sin mermas y correctamente estandarizada. El objetivo final del presente estudio fue reducir tiempos improductivos en una MYPE del sector agrícola, identificando y solucionando el problema principal y evitando la aparición de sus causas raíz. El principal problema encontrado fue el tiempo improductivo que se genera en los procesos de Abonado y Cosecha. Método: para dar solución a dicho problema, se diseñó un modelo de estandarización de procesos, empleando la herramienta de mejora continua PDCA. Resultados: como principal resultado del modelo propuesto de estandarización tenemos que la productividad se incrementó en un 25% en relación a la última producción del año 2019, además, entre otros resultados, se obtuvo la reducción en los tiempos improductivos en un 36%, lo que significó para la empresa un ahorro de S/. 5,762.62. Conclusión: El estudio demostró que, con un replanteamiento ordenado de los procesos y la disposición de la empresa a cooperar con la mejora, se pueden lograr resultados positivos, a pesar de que el proyecto no significa una gran inversión.The present research article wishes to bring to the attention of the reader the low productivity that exists in organic food production; this study will focus specifically on grape production. The analysis and information gathered in the organic agriculture sector has allowed us to decipher that this problem arises due to the unproductive times that originate in each phase of the production of organic grapes, generating unnecessary costs. The final objective of the present study was to reduce unproductive time in an MSE of the agricultural sector, identifying and solving the main problem and avoiding the appearance of its root causes. The main problem found was the unproductive time generated in the Fertilizer and Harvest processes. Method: To solve this problem, a process standardization model was designed, using the PDCA continuous improvement tool. Results: As the main result of the proposed model of standardization we have that productivity increased by 25% in relation to the last production of 2019, in addition, among other results, we obtained the reduction in unproductive time by 36%, which meant a saving of S/. 5,762.62 for the company. Conclusion: The study showed that, with an orderly rethinking of processes and the company's willingness to cooperate with improvement, positive results can be achieved, even though the project does not involve a large investment.
Trabajo de investigación
33
Vicentini, Nicola. "Screening on the functionalization of carbon nanostructures and their compatibilization in polymer-based composite materials." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3424578.
Abstract:
Composites of carbon nanostructures (CNSs) and biocompatible polymers are promising materials for a series of advanced technological applications, ranging from biomedicine and bioelectronics to smart packaging and soft robotics. In this thesis, we present three types of organic functionalized CNSs, namely 4-methoxyphenyl functionalized multi-walled carbon nanotubes, carbon nanohorns and reduced graphene oxide, used as nanofillers for the preparation of homogeneous and well-dispersed composites of poly(l-lactic acid), a biocompatible and biodegradable FDA approved polymer. A thorough characterization of the composites is given in terms of calorimetric response, electrical and mechanical properties. Significant differences are observed among the different types of CNS nanofillers, underlying the key role played by the nanoscale shape, and distribution of the components in driving the macroscopic behavior of the composite material. Surface properties are probed through advanced atomic force microscopy techniques, on both flat substrates (films) and confined systems (nanofibers). All these composites are found to be fully biocompatible when tested as scaffolds for supporting the proliferation, and differentiations of human neuronal precursor cell line SH-SY5Y, and of human Circulating Multipotent stem Cells (hCMCs). Prototypes of Nerve Guide Conduits (NGCs) for in vivo tests were also designed, and obtained using the material based on functionalized Multi Walled Carbon Nanotubes (MWCNTs), and tested on mice, finding promising results. We also propose the functionalization of MWCNTs with “functional” organic groups (4-benzoic acids and styrene), and performed an additional derivatization on them respectively through an amidation reaction, and a “grafting from” polymerization. The so obtained CNSs are promising for the preparation of more complex composite materials. Finally, we analyzed the reaction pathway of the Tour functionalization of CNSs, and we hypothesized that the real reaction scheme could be a balance between two different pathways.Le nanostrutture di carbonio (CNS) e i polimeri biocompatibili sono materiali molto promettenti in un grande numero di applicazioni tecnologicamente avanzate, che vanno dalla biomedicina e bioelettronica, allo smart packaging e alla robotica soft. In questa tesi presentiamo la funzionalizzazione organica tramite addizione della p-metossianilina di 3 diverse CNS: i nanotubi di carbonio a parete multipla, i nanoconi di carbonio e il grafene ossido risotto. Questi materiali sono impiegati come additivi per la preparazione di materiali compositi nanostrutturati a base di acido polilattico (PLLA). In questa tesi è riportata una completa caratterizzazione in termini di proprietà termiche, elettriche e meccaniche. Sono evidenti differenze significative tra le tre nanostrutture e sul loro effetto sulle proprietà dei compositi; ciò sottolinea il ruolo chiave giocato dalla morfologia e forma a livello nanometrico nell’interazione nanostruttura-polimero e quindi nella determinazione delle caratteristiche finali del composito. La superfice dei materiali è stata caratterizzata tramite AFM e CAFM sia nella forma di film piatti sia nella forma di nanofibre ottenute tramite eletrospinning. Sono state quindi testate le proprietà di biocompatibilità e induzione/controllo della differenziazione sia su cellule umane neuronali (SH-SY5Y), sia su cellule staminali umane (hCMCs). I materiali a base di nanotubi di carbonio a parete multipla (MWCNT) ottenuti sono stati utilizzati per la preparazione di prototipi di nerve guide conduits (NGC) per operazioni in-vivo su topi, ottenendo risultati molto promettenti. Presentiamo anche la funzionalizzazione dei MWCNT con 2 gruppi organici “funzionali” (l’acido p-benzoico e lo stirene) sui quali è stata effettuata una derivatizzazione aggiuntiva sfruttando rispettivamente una reazione di ammidazione e una reazione di polimerizzazione “grafting from”. Infine abbiamo analizzato lo schema di reazione della funzionalizzazione di Tour delle CNS a abbiamo ipotizzato che la reale via sintetica sia costituita da due differenti vie in equilibrio tra di loro.
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Krieger, Eva Janine. "Microbial presence and potential to reduce sulfur content in fossil fuels, and The isolation and characterization of an organism capable of degrading pyridine /." The Ohio State University, 1991. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487758680162849.
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Sil, M. C. "Effect and position of molecularly engineered bipropylenedioxythiophene-bridged donar/ acceptor dyes in dye-sensitized solar cells (DSSC): homo and hetero-dimeric Di-anchoring organic dyes for panchromatic light absorption with controlled dye aggregation and reduced charge recombination." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2018. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/4493.
Abstract:
Chapter 1. Introduction
a) Dye-sensitized solar cells: Dye-sensitized solar cells have emerged as potential device architecture to harvest the solar energy due to easy device fabrication and diversity in key components such as semiconductors, dyes, electrolytes and cathode materials. Ever since the discovery of homoleptic metallated ruthenium-based dyes with 7.12% device efficiency by O’Regan and Grätzel, last two and half decade research on the functional materials provided deeper understanding of device structure and various pathways associated with interfacial charge transfer and recombination processes. Dye design with panchromatic absorption, avoiding both charge recombination and dye aggregation achieved high device efficiencies by increasing the Jsc and Voc besides the choice of electrolyte having minimum loss-in-potentials. The structure-property relationship of organometallic and metal-free organic dyes have been carried out, so far the best conversion efficiency of about 13% was achieved for zinc-porphyrin dye and 12.5% for indenoperylene dye with cobalt (II/III) redox couple.
One of the advantages of having D/A metal free organic dyes is that it utilizes simple precursors to tune the optical and electrochemical properties and which developed high molar absorptivity dyes with strong intermolecular charge transfer (ICT). Dyes with D--A, and D-A--A configurations provided good harvesting efficiency in the visible and far-red regions, respectively, whereas few chromophores such as polymethine, porphyrin, and phthalocyanine dyes have been explored for photo-current generation in near infrared (NIR) region.
DSSC device contains dye coated TiO2 as photo anode, platinized FTO as cathode with electrolyte (Figure 1). Upon photo-excitation, a photo-excited electron is injected from the excited state (LUMO) of the dye into the conduction band of the TiO2. The oxidized dye molecules are then regenerated by the electrolyte leaving the oxidized electrolyte in the system. The injected electron in TiO2 percolates through the film and collected at a transparent conductive layer of fluorine-doped tin oxide (FTO) glass substrate, on which the TiO2 film is formed. After passing through an external circuit, the electron is reintroduced into the DSSC device at the Pt cathode, where the oxidized electrolyte is reduced to regenerate the electrolyte.
b) Statement of Problem:
Out of various interfaces in DSSC device, dye-TiO2 interface plays an important role for charge injection and dye regeneration besides aggregation of dye on the TiO2 surface. Charge injection from aggregated structure that contributes to the device performance is varied and which can be modulated by co-adsorbing the dyes with optically transparent CDCA. Hence, controlling the dye-dye interaction on the TiO2 surface has become one of the challenging tasks for synthetic chemists besides having desired optical band gap of dyes. Dimeric dyes that are connected through spiro--spacer showed better device efficiency than corresponding monomeric units. Generally, for panchromatic absorption, two or more dyes with complementary absorption properties were adsorbed to enhance the light harvesting properties over solar spectrum. In the present approach, this critical problem is solved by connecting two structurally different dyes through spiro-linkage. Spiro-based -spacer spiroBiProDOT has been explored to synthesize dimeric dyes with orthogonal dye orientation.
Chapter 2. Orthogonally Functionalized Donor/Acceptor Homo- and Heterodimeric Dyes for Dye-Sensitized Solar Cells: An Approach to Introduce Panchromaticity and Control the Charge Recombination
Organic dyes possessing conjugated π-framework forms closely packed monolayers on photoanode in dye-sensitized solar cell (DSSC), because of the limitation to control the orientation and the extend of intermolecular π-π interaction, self-aggregation of dyes leads to reduced cell performance. In this chapter, a series of homodimeric (D1-D1 and D2-D2) and heterodimeric (D1-D2 and D2-D4) donor/acceptor (D/A) dyes containing spiroBiProDOT-spacer were designed and synthesized by utilizing Pd-catalyzed direct arylation reaction and compared the device performance with model monomeric dyes, D1 and D2 (Figure 2). Both the thiophenes (π-spacer) of spiroBiProDOT were functionalized with same or different donor groups which led to homodimeric and heterodimeric chromophores in a single sensitizer. The homodimeric spiro-dye D1-D1 showed higher power conversion efficiency (PCE), of 7.6% with a Voc and Jsc of 0.672 V and16.16 mA/cm2, respectively. On the other hand, the monomeric D1 exhibited a PCE of 3.2 % (Voc of 0.64V and Jsc of 7.2 mA/cm2), which is lower by 2.2 fold compared to dimeric D1-D1 analogue. The spiro-unit provides flexibility between the incorporated chromophores to orient on TiO2 surface due to four sp3-centers, which arrest the molecular motions after chemisorption. This study showed a new molecular approach to incorporate two different chromophores in the dimeric dye possessing complementary absorption characteristics towards panchromatic light absorption. The attenuated charge recombination at TiO2/Dye/redox couple interface in case of D1-D1, owing to better passivation of TiO2 surface due to the spiro spacer was elucidated through electrochemical impedance spectroscopy. The FT-IR spectrum of D1-D1 adsorbed on TiO2 film indicated both the carboxylic units were involved in chemisorption which makes strong coupling between dye and TiO2.
Chapter 3. Symmetrical and Unsymmetrical Bi-Chromophoric Squaraine Based Sensitizer for Dye-Sensitized Solar Cells
Dimeric derivatives of symmetrical (Dsq-Dsq) and unsymmetrical (D1-Dsq) spiro-squaraine dyes were synthesized by using direct arylation method (Figure 3). Photo-physical, electrochemical properties were evaluated for the feasibility of charge injection and dye regeneration processes which is required for utilizing the synthesized dyes as an active material for photovoltaic device fabrication. A model squaraine dye Dsq was also synthesized and characterized. In Dsq-Dsq dye, two Dsq monomeric units were attached through spiroBiProDOT unit. Similarly, D1-Dsq contains two different dyes namely Dsq and D1 (donor-- acceptor) connected through spiro-spacer. Excitation energy transfer between photoexcited D1 and Dsq was explained by using Förster resonance energy transfer (FRET). Compared to Dsq-Dsq, unsymmetrical spiro-squaraine dye, D1-Dsq, is more efficient in terms of circuit voltage Voc = 0.607 V, short-circuit current density Jsc = 6.6 mA/cm2, fill factor (ff) = 69% and power conversion efficiency (η) = 2.8 % under 1 sun, AM1.5G, whereas D1-Dsq dye showed the Voc = 0.612 V, Jsc = 9 mA/cm2, ff = 71% and η = 3.9%. From the IPCE profile of D1-Dsq, absence of response in the visible region, where D1 absorb the photons, indicates that efficient energy transfer from exited D1 to Dsq. A new dye D1-Dsq has been developed to improve the performance of DSSCs by Förster resonance energy transfer (FRET), in addition to retarding the charge recombination for the improved DSSC device performance.
Chapter 4. Effect of Position of Spiro-Bipropylenedioxythiophene-Spacer in D--A Dyes for Dye-Sensitized Solar Cell
To understand the effect of position spiro-spacer in D--A dyes, spiro-spacer near (TT1) and away (T1T) from anchoring unit were designed, synthesized and characterized (Figure 4). The dimeric spiro-dye T1T showed higher power conversion efficiency (PCE), with 3.9 % with a Voc and Jsc of 0.593 V and 9.09 mA/cm2, respectively, under simulated AM 1.5G illumination (100 mW/cm2) which is 1.6 times higher than that of isomeric TT1. Further electrochemical impedance spectroscopy indicates that the charge transfer resistance for the T1T (8.62 ohm) is higher than that of TT1 (6.75 ohm). Accordingly, dye TT1T designed and synthesized which showed the PCE of 4.16 % (Voc and Jsc are 0.589 V and 9.79 mA/cm2 respectively). The positioning of branching spiroBiProDOT-spacer makes an impact on the device performance, which might be due to effective passivation, originates from strong interaction between the dye and TiO2 in the case of T1T.
Chapter 5. Orthogonally Functionalized Molecular Diad Containing D--A Dye and Hole Transport Material for Dye-Sensitized Solar Cell
An orthogonally functionalized molecular diad containing D--A dye and hole transport material (D1-HTM)for dye-sensitized solar cell were synthesized (Figure 5) and characterized by electrochemical, photo physical methods and fabricating photovoltaic devices. The main objective of this work is to embarrass the charge recombination by appending a hydrophobic triarylamine moiety, which is orthogonally attached to that D--A part through spiroBiProDOT-spacer. Dye regeneration may be faster due to faster hole transfer from dye (D--A) to I-/ I3- system through HTM part. Fluorescence quenching experiments indicate that electron transfer from hole transporting material (PTS1, HTM-1) to excited D1-D1 and D1 dye. Cyclic voltammetry was carried out to evaluate the HOMO energy level of D1-HTM and LUMO level was calculated from the band gap. LUMO energy level of this dye is higher than that of the conduction band of TiO2 and at the same time HOMO is lower than that of the energy level of the electrolyte which is required for an efficient charge injection and dye regeneration processes. Photo-voltaic studies shown that the best efficiency (2.24 % with a Voc and Jsc of 0.590 V and 5.27 mA/cm2) was obtained of D1-HTM by using 5 equivalent of CDCA.Funding from NWP0054 (CSIR-TAPSUN), and SERB-EMR/2016/007114
AcSIR
36
Sil, M. C. "Effect and position of molecularly engineered bipropylenedioxythiophene-bridged donor/acceptor dyes in dye-sensitized solar cells (DSSC): homo and hetero-dimeric Di-anchoring organic dyes for panchromatic light absorption with controlled dye aggregation and reduced charge recombination." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2018. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/4355.
37
Gypser, Stella [Verfasser], Dirk [Gutachter] Freese, and der Zee Sjoerd E. A. T. M. [Gutachter] van. "Identification of phosphate adsorption mechanisms on Fe- and Al-hydroxides and the influence of inorganic and organic compounds to reduce long-term phosphorus fixation on mineral surfaces / Stella Gypser ; Gutachter: Dirk Freese, Sjoerd E.A.T.M. van der Zee." Cottbus : BTU Cottbus - Senftenberg, 2020. http://d-nb.info/1206936932/34.
38
Vigano', M. "SYNTHESIS AND APPLICATIONS OF NEW LIGANDS OF THE BIAN FAMILY: FROM HYDROGENATED DERIVATIVES TO NEW CHIRAL BIANS." Doctoral thesis, Università degli Studi di Milano, 2013. http://hdl.handle.net/2434/214935.
Abstract:
Synthesis of new reduced Ar-BIANH2 compounds, investigations of the reactivity and applications of the so obtained compounds as ligands for transition metal complexes. Synthesis of new chiral Alkyl and Aryl-BIAN.
39
Suchá, Kateřina. "Hodnocení kvality/zdraví půdy v blízkosti obce Bohaté Málkovice." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392022.
Abstract:
Diploma thesis evaluates quality and healthiness of the soil health located close to Bohate Malkovice focusing on changes in both physical and chemical characteristics of the soil in time. The theoretical part describes physical, chemical, and biological parameters of the soil. Selected physical parameters are structure, texture, determination of measured weight, bulk density of the soil, porosity, actual volumetric water content of the soil, aeration, saturated and unsaturated hydraulic conductivity, infiltration, and colour. Chosen chemical parameters are pH, carbonates, soil electrical conductivity, and humus content. Picked biological parameters are microbial biomass, respiration, nitrogen content, and weed infestation. The practical part analyses selected indicators of quality of the soil from the location of the experiment close to Bohate Malkovice. The area under evaluation has been treated using reduced tillage for long term. The practical part is based on the laboratory examination of disturbed and undisturbed soil samples taken between years 2016 and 2018. Based on outcome results we can evaluate the quality of the soil considering plants growth, development, and soil fertility.
40
Schneiderová, Šárka. "Účinky hospodaření s půdou na kvalitu půdy v blízkosti obce Šardičky." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2019. http://www.nusl.cz/ntk/nusl-392105.
Abstract:
This diploma thesis is focused on influence of reduced tillage technology of soil processing on it´s near-surface soil layer (0 to 10 cm). The research was carried out on agricultural land near Šardičky village, where company ZEMO spol. s r.o. provides long-term use of reduced tillage technology. In 2016 the soil quality in this site was evaluated by using physical and hydrophysical parameters, results are presented in the previous bachelor thesis "Selected hydrophysical parameters as indicators of soil quality.". In diploma thesis in addition chemical and other hydrophysical properties have been evaluated to provide a comprehensive assessment of soil quality. In 2016, poppy seed was grown on this site and spring barley was grown in 2017 and 2018. Grab samples and intact soil cores were taken during the vegetation period of the crop. After three years of experimental research, in which I participated, it is possible to assess the development of individual parameters and the influence of reduced tillage technology on near-surface soil layer. The theoretical part of the diploma thesis deals with the description of the reduced tillage technology and problematics of the determination of soil parameters, which are used for evaluation of the quality of the near-surface layer. The practical part deals with evaluation of these parameters according to various authors and describes the development of soil quality during years 2016, 2017 and 2018.
41
You, Sheng Mu. "Metal organic frameworks as efficient photosensitizer for TiO₂ nanoarray anode and application to water splitting in PEC cells Fe/Ni Bimetallic organic framework deposited on TiO₂ nanotube array for enhancing higher and stable activity of oxygen evolution reaction Novel nano-architectured water splitting photoanodes based on TiO₂-nanorod mats surface sensitized by ZIF-67 coatings Surface sensitization of TiO₂ nanorod mats by electrodeposition of ZIF-67 for water photo-oxidation Electrochemically capacitive deionization of copper (II) using 3D hierarchically reduced graphene oxide architectures." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASF015.
Abstract:
Les réserves de combustibles fossiles diminuent et leur utilisation illimitée depuis la révolution industrielle a généré de profonds changements du climat, notamment des cycles de la température atmosphérique. Stocker l'énergie solaire sous forme d'hydrogène produit par dissociation de l'eau est un moyen idéal pour combattre le réchauffement climatique. Les matériaux de la famille des «metal organic framework» (MOF) commencent à être utilisés comme photo-électrocatalyseurs, notamment pour la photo-dissociation de l'eau. Leur porosité extrêmement élevée et leur grande polyvalence, tant chimique que structurelle, les désignent comme des candidats potentiels pour faciliter l'absorption du rayonnement solaire et catalyser la dissociation de l'eau dans les cellules photoélectrochimiques. En contrôlant la composition chimique et le dopage du linker utilisé dans le MOF, il est possible d'ajuster l'énergie de la bande interdite, de favoriser la fonctionnalisation sur des substrats très variés ou encore d'ajuster leur résistance à la corrosion dans divers environnements chimiques. Ce sont donc des matériaux d'un grand intérêt pour la catalyse, l'électrocatalyse ou la photo-électro-catalyse. D'autre part, le TiO₂ nano-structuré, par exemple sous forme de tapis d’épaisseur micrométrique de nanotubes ou de nanofils, parfois appelé TNA, est un matériau bien adapté à la construction de photoanodes pour le dégagement d'oxygène en milieu aqueux. Il a déjà été largement étudié et décrit dans la littérature. Au cours de notre thèse, nous avons fabriqué des matériaux composites constitués de MOF de métaux de transition (Ni, Co, Fe) déposés sur TNA (TDNR et TNTA). Pour cela, nous avons utilisé une méthode électrochimique d'électrodéposition. Cela nous a permis de déposer des nanoparticules métalliques sur du TNA à potentiel fixe - 1,0 V puis de les transformer par réaction chimique avec des ligands organiques (BTC, BDC, et 2MZ) par voie thermo-thermique. Les matériaux obtenus présentent une activité électrocatalytique significative et une excellente durabilité photoélectrochimique. Ces matériaux composites ont été utilisés avec succès comme phase active dans des photo-électrodes pour la réaction de dégagement d'oxygène moléculaire (OER)The fossil fuel reserves are dwindling and their unrestricted use has generated profound changes in Earth's surface temperature and climate. Storing solar energy in the form of hydrogen produced by dissociation of water is an ideal way to mitigate global warming. Materials from the “metal organic framework” (MOF) family are starting to be used as photo-electrocatalysts, especially for photo-dissociation of water. Their extremely high porosity and their great versatility, both chemical and structural, designate them as potential candidates to facilitate the absorption of solar radiation and catalyze the dissociation of water in photoelectrochemical cells. By controlling the chemical composition and doping of the linker used in the MOF, it is possible to adjust the band gap energy, to favor the functionalization on very varied substrates or even to adjust their resistance to corrosion in various chemical environments. They are therefore materials of great interest for catalysis, electrocatalysis or photo-electro-catalysis. On the other hand, nano-structured TiO₂, for example in the form of nanotube or nanowire mats, sometimes called TiO₂ nanoarray (TNA), is a material very suitable for the construction of photoanodes for the evolution of oxygen in aqueous medium. It has already been extensively studied and described in the literature. During our thesis, we manufactured composite materials made up of MOFs of transition metals (Ni, Co, Fe) deposited on TNA (network of nanotubes or nanowires). For this we used an electrochemical method of electrodeposition (cyclic voltammetry). This allowed us to deposit metallic nanoparticles on TNA with fixed potential - 1.0 V and then transform them by chemical reaction with organic ligands (1,3,5-benzenetricarboxylic acid, BTC, 1,4-benzenedicarboxylic acid, BDC and imidazole, 2MZ) by thermal-thermal route. The materials obtained exhibit significant electrocatalytic activity and excellent photoelectrochemical durability. These composite materials have been successfully used as an active phase in photo-electrodes for the oxygen release reaction (OER)
42
Piñana, Sánchez José Luis. "Complicaciones orgánicas en el transplante de progenitores hematopoyéticos con acondicionamientos de intensidad reducida." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/368192.
Abstract:
This thesis presents the results of five studies that share a common bond; the analysis of organic complications (respiratory, renal and neurological) in a homogeneous cohort of recipients who received an Allo-HSCT-RIC at a single institution. The chosen scope is of particular interest to the extent that patients receiving this type of transplant are usually older, having more comorbidities, having received a greater number of previous treatments. This conditions might influence a higher risk of organic complications. Thus, the study of the organic complications could properly determine the Allo-HSCT-RIC’s tolerance in this specific group of patients. The first paper analyzed the development of pulmonary complications. The second analyzed respiratory viral infections and invasive pulmonary invasive aspergillosis (IA). The third paper evaluated the kidney complications after Allo-HSCT-RIC. The fourth paper was focused on neurological complications in the same cohort of patients.
Results: The first study included 188 recipients of Allo-HSCT-RIC and analyzed the predictive value of pulmonary function test (PFT) in pulmopnary complications (PC). The cumulate incidence of PC was 45% [95% confidence interval (CI.), 38–53%]. Multivariate analysis showed that TLC was significantly associated with PC, nonrelapse mortality (NRM) and overall survival (OS), (Hazard Ratio (HR) 4.2, 95% CI. 2–8.5; HR 3.8, 95% CI. 1.7–8.5; HR 2.3, 95% CI. 1.3–4.1, respectively, P = 0.01), while abnormal FVC had a negative impact on PPC and OS (HR 1.8, 95% CI. 0.98–3.6, P = 0.06 and HR 1.7, 95% CI. 1.1–2.6, P = 0.008). The second included 219 consecutive recipients of Allo-HSCT-RIC. The 4-year incidence of IA was 13% (95% CI, 4–24%). In multivariate analysis, risk factors for developing IA were steroid therapy for moderate-to-severe graft vs host disease (HR 2.9, P<0.03), occurrence of a lower respiratory tract infection (LRTI) by a respiratory virus (RV) (HR 4.3, P<0.01) and CMV disease (HR 2.8, P=0.03). The occurrence of IA had no effect on survival (P=0.5). The third manuscript include 188 Allo-HSCT-RIC recipients. The cumulative incidence of acute renal failure (ARF) at 1 year was 52%. The risk factors associated with ARF in multivariate analysis were: administration of MTX (HR 1.9, P =0.02), more than 3 lines of therapy prior to Allo-RIC (HR 1.8, P <0.01), diabetes mellitus (HR 2.1, P<0.01), and GVHD grade III-IV (HR 2.1, P =0.015). Patients who experienced ARF had lower 1-year overall survival (OS; 53% versus 74%, P<0.05). In the fourth, the author analyzes the characteristics, incidence and risk factors of neurological complications (NC) (both CNS and PNS) in the same patient population Alo-TPH-AIR and how they affect overall survival. The 4-year cumulative incidence of NC was16% (95% CI, 11-23). CNS complications included nonfocal encephalopathies in 11 patients, meningoencephalitis in 5 patients, and stroke or hemorrhage in 4. PNS complications consisted of 5 cases of mononeuropathies and 3 cases of polyneuropathies. Drug-related toxicity was responsible for 10 of the 31 events (32%) (8 caused by CsA). Overall, patients presenting NC showed a trend for higher 1-year nonrelapse mortality (NRM) (37% versus 20%, P=0.08). In patients with CNS involvement, 1-year NRM was significantly worse (42% versus 20%, P5.02). CNS NC also had a negative impact on 4-year overall survival (OS; 33% versus 45%, P5.05).
Conclusions: The organic complications in the Allo-HSCT-RIC setting were diverses, frequent but did not seem more common compared to those reported in the myeloablative Allo-HSCT. The identification of several risk factors for these complications opens a window to explore further protocol modifications by reducing the conditioning doses or the application of prophilactic actions for patients at higher risk of organic complications and NRM.
43
Achuo, George. "Partner satisfaction and renewal likelihood in consumer supported agriculture (CSA) : a case study of The Equiterre CSA network." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=19555.
44
Broughton, Sarah Elizabeth. "The Effects of Living Mulches on Organic, Reduced-Till Broccoli Growth and Management." 2010. http://trace.tennessee.edu/utk_gradthes/776.
Abstract:
Conservation tillage programs have been successfully implemented for many agronomic cropping systems, but adoption of reduced tillage for vegetable crops has been slow. As many conventionally managed conservation tillage programs rely on synthetic herbicides for clean cultivation, alternative methods must be devised to suppress weed pressure and reduce reliance on mechanical cultivation to aid in the development of reduced tillage programs for organic cropping system. Strip tillage is a reduced tillage method that is well suited to vegetable crop production, and the utilization of cover crops and living mulches between rows provides a viable weed management option for organic systems.
The adoption of reduced tillage and the inclusion of cover crops and living mulches have the potential to alter the agroecosystem in ways that impact plant development and crop yield, and augment weed, insect and disease pressure. The current study focuses on the use of strip tillage and the interplanting of spring-seeded living mulches and overwintered cover crops for early-season organic broccoli production. Data were collected on ground cover provided by cover crops and living mulches, crop physiological status (petiole sap nitrate, photosynthetic rate, plant growth and crop biomass) and pest pressure (weed relative abundance, insect density and disease incidence and severity).
Living mulches provided the greatest ground coverage when cover crop establishment was poor; however, when cover crops produced a large amount of biomass, living mulch establishment was suppressed. Decreases in herbivorous pests and suppression of grassy and cool-season weed species were also observed, indicating that strip tillage and the use of spring-seeded living mulches and overwintered cover crops may provide beneficial pest management strategies. Decreases in crop growth and biomass, and decreases in petiole sap nitrate were observed, however, indicating reductions in crop vigor and yield may be expected with the implementation of strip tillage and living mulch crops. It is suggested that the utilization of strip tillage and living mulch crops may provide benefits to pest management which may outweigh declines in yield.
45
LI, JHONG-YU, and 李忠諭. "Reduced graphene oxide modified organic Fabry-Perot interference for color selection dye-sensitised solar cell." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/b8r8ku.
Abstract:
碩士國立雲林科技大學
電子工程系
107
The purpose of the study was to modify solar cells with the reduced graphene oxide. The organic Febry-Perot provides the choice of color. There are three parts in the thesis: (1) using Hammer’s method to prepare different percentage by weight of reduced graphene oxide to modify dye sensitized solar cell, (2) preparing hole type PEDOT: PSS, electronic type PCBM and organic type Fabry-Perot to choose different color, using Macleod to simulate different depth corresponding to different color, (3) the structure of reduced graphene oxide and organic type Fabry-Perot with dye-sensitized solar cell is FTO/TiO2-rGO/Ag/Fabry-Perot. This thesis mainly discusses the use of thrips to prepare different weight percentages (1wt%, 5wt%, 10wt%) of reduced graphene oxide modified dye solar cells and study their optimal electrical efficiency, and then use the organic material hole type PEDOT: PSS and electronic PCBM combine organic Fabry-Perot to select different colors, and use Macleod to simulate different thicknesses corresponding to different colors. The experimental results are measured by UV/VIS spectrometer, Raman spectrometer, XRD and SEM to reduce graphene oxide. The material is synthesized and the optimum efficiency is measured by blending the concentration. The optimum parameters for the reduced graphene oxide are 5wt% and the efficiency is 3.6%, which is 28%. Finally, the organic Fabry-Perot is combined, the efficiency is 4.05%, and the original ratio is increased by 44%.
46
Podolsky, Kristen. "Reduced tillage implements for management of an organic green manure: effects on nitrogen, weeds and wheat yield." 2013. http://hdl.handle.net/1993/22160.
Abstract:
Reducing tillage in Canadian organic cropping systems is a priority to preserve soil quality and increase long term sustainability. Novel methods for management of cover crops offer farmers the opportunity to reduce both tillage and herbicide use during this phase of the crop rotation but require further investigation across a range of cropping systems. The objective of this study was to compare the blade roller, flail mower and wide blade cultivator (noble blade) with standard tillage for management of an annual pea-barley (Pisum sativum L. – Hordeum vulgare L.) green manure in the Canadian prairies. The experiment was conducted twice at Carman, Manitoba (long-term organic management) and Lethbridge, Alberta (previous herbicide and fertilizer use) from 2010-2012. The green manure was planted in spring of year 1 and grown until pea full bloom when five management treatments were applied; 1) standard tillage with a field disc 2) blade roller, 3) blade rolled once plus tillage in late fall and spring, 4) wide blade cultivator and 5) flail mower. Spring wheat (Triticum aestivum L.) was planted in spring of year 2. The effect of management treatment on surface residue, soil nitrogen, soil microclimate, weed population dynamics and subsequent spring wheat yield was evaluated. At Carman, managing green manure without tillage (blade roller or flail mower) significantly increased winter annual and perennial weed pressure and reduced soil nitrate availability; these factors contributed to wheat yield reductions in both years compared to standard tillage. Wide blade cultivation and blade rolling plus tillage maintained crop yield at one and both years, respectively, compared to tillage. Without sufficient mulch for weed suppression, soil disturbance was required to control weeds and ensure adequate nitrogen uptake in the crop. Replacing one tillage operation with blade rolling reduces energy costs and erosion risk without sacrificing yield. At Lethbridge, previous herbicide and fertilizer use masked the effect of green manure management. Markedly different results from Carman and Lethbridge emphasize that the adaptability of reduced tillage green manure management is site-specific due to differences in climate and cropping history. This research highlights important differences in the efficacy, erosion risk, weed control, nitrogen availability, main crop yield and energy savings associated with each management method.
47
Gillespie, Scott. "Weed management in reduced-input no-till flax production." Thesis, 2006. http://hdl.handle.net/1993/278.
Abstract:
The goal of the project was to enhance the period of weed growth prior to seeding
in order to reduce weed emergence and weed competition after the crop has been planted.
Weed growth was stimulated using either light tillage or by applying nitrogen fertilizer
early in the spring. Light disturbance significantly increased pre-seed weed emergence
while early applied nitrogen did not appear to have an effect. Post seeding weed
emergence levels and weed biomass were similar among the light tillage and early
nitrogen treatments. Therefore the goal of decreasing weed competition after seeding
was not attained. Future research should focus on long-term strategies to reduce weed
populations in field rather than seasonal strategies.October 2006
48
Bo-Wun, Gu, and 古博文. "Study on Organic Solar Cells with Reduced Graphene Oxide/ Nickel Oxide/ Ag Nanoparticles as Hole Transport Layer." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/51580383521146732776.
Abstract:
碩士國立勤益科技大學
化工與材料工程系
103
Graphene exhibits good electron conductivity, thermal conductivity and strength. Graphene may become the new electron conductivity material in place of silicon in the future. Graphene may be used for flexible display and polymer solar cell due to its conductivity, transparent and toughness. In this study, we used reduced graphene oxide (r-GO, reduced-GO)、nickel oxide (NiOx) and oleic acid silver (OA-Ag) as the hole transport layer (HTL) of polymer solar cells. We studied the effect of different layer and reduction temperature on the characteristics of polymer solar cells. The structures of solar cell were three types of (A) ITO / r-GO(1.0 mg / ml, 1 ~ 3 layers)/P3HT: PC61BM / Ca / Al, (B) ITO / r-GO / NiOx(0.5M, 1 ~ 3 layers) / P3HT: PC61BM / Ca / Al, and (C) ITO / r-GO / NiOx / OA-Ag (1.0 mg / ml, 1 ~4 layers)/ P3HT: PC61BM / Ca / Al。 We used the UV-Vis, PL, SPM, SEM to measure the absorbance, radiation fluorescence intensity, surface roughness and morphology, respectively. We used the solar simulator to measure J-V characteristic and power conversion efficiency of the device. When the HTL of cell was two layers of r-GO (r-GO-2) and reduced at 250℃ in the structure (A). The cell exhibited the highest power conversion efficiency of 2.07 %. When the HTL of cell was two layers of r-GO and two layers of NiOx (r-GO-2/NiOx-2) in the structure (B). The cell exhibited the highest short-circuit current density of 8.34 mA/cm2 and power conversion efficiency of 2.93 %. When compared to structure (A), the short-circuit current density was increased from 6.23 mA/cm2 to 8.34 mA/cm2, an increase of 33.9 %. The power conversion efficiency was increased from 2.07 % to 2.93 %, an increase of 41.5 %. From these results, adding the nickel oxide on the r-GO as hole transport layer can increase the short-circuit current density and power conversion efficiency of the polymer solar cells. Reduced graphene oxide, nickel oxide, and oleic acid silver were used as HTL in the structure (C). The cell had the highest short-circuit current density and power conversion efficiency when its HTL was r-GO-2/NiOx-2/OA-Ag-3. When compared to structure (B), the short-circuit current density was increased to 9.11 mA/cm2, an increase of 9.2 % and the power conversion efficiency was increase to 3.45 %, an increase of 17.7 %. From these result, we found that adding oleic acid silver onto the r-GO/NiOx HTL can increase the short-circuit current density and power conversion efficiency of the polymer solar cell. The structure (C) exhibits the better performance than those of structure (A) or structure (B).
49
Rumsey, Ian Cooper. "Characterizing reduced sulfur compounds and non-methane volatile organic compounds emissions from a swine concentrated animal feeding operation." 2010. http://www.lib.ncsu.edu/theses/available/etd-02042010-235630/unrestricted/etd.pdf.
50
Lin, Kuei-Ting, and 林奎廷. "Metal-Organic Frameworks derived Hollow Polyhydron Metal Oxide Hybridized with Reduced Graphene Oxide for Lithium Ion Batteries Application." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/47304670854684177650.
Abstract:
碩士國立臺灣師範大學
化學系
103
Cupric oxide as anode for lithium ion batteries(LIB) has attracted much attention due to its high theoretical capacity(~670mAh g-1) and low cost. However, the disadvantages are poor electrical conductivity and large volume expansion during lithiation resulting in fast fading of the capacity of cupric oxide. In this study, we synthesized hollow polyhydron rGO-Cuox by two step sintering graphene oxide and metal-organic frameworks compound [Cu3(btc)2]n(btc = benzene-1,3,5-tricarboxylate). The obtained rGO-Cuox materials were used in a lithium-ion battery and tested the electrical performance. The first cycle capacity is 662 mAh g-1 at rate of 200mA g-1. From the third cycle, the capacity increased with cycle. The capacity is 700mAh g-1 at 220 cycle . Similar phenomenon appeared at rate of 1000mA g-1. Compare to graphene oxide and metal-organic frameworks compound, the rGO-Cuox composite material successfully improved the performance of lithium ion batteries.