Produzione di biogas dagli scarti della lavorazione degli agrumi

La presente tesi di laurea tratta la valorizzazione degli scarti della lavorazione degli agrumi. Tutti i processi di trasformazione utilizzati nell’industria agrumaria danno origine a tre prodotti principali: succo, olio essenziale e pastazzo; il terzo, sottoprodotto a basso valore o scarto di lavorazione, è una biomassa vegetale costituita da scorze, detriti di polpa, semi e frutti di scarto. Questo lavoro si è concentrato su due aspetti fondamentali: lo studio dei possibili utilizzi del pastazzo di agrumi, che si può considerare una fonte di sostanze ad alto valore aggiunto, e la valorizzazione di tale sottoprodotto mediante digestione anaerobica per la produzione di biogas. La composizione chimica degli scarti della lavorazione degli agrumi offre ampie possibilità di utilizzazione: come alimento zootecnico, per la produzione di compost, per l’estrazione di pectina, fibre alimentari e oli essenziali, per il recupero di limonene e per produrre bioetanolo. Infine di recente il pastazzo è stato individuato come componente nella produzione di biogas, attraverso la digestione anaerobica; ciò risulta coerente con il quadro normativo riguardante gli incentivi per la produzione di biogas. E' stato analizzato un caso pratico, l’impianto di produzione di biogas alimentato a biomasse, situato in Sicilia, in contrada Nuova Scala a Mussomeli (CL); l’impianto ha una potenza di 999 KW ed è attivo dal 31 Dicembre 2012. In generale, affinchè si realizzi un corretto dimensionamento di un impianto di produzione di biogas, è necessario conoscere il potenziale metanigeno, che esprime la quantità di biogas metano massimo potenzialmente ottenibile da una biomassa, e la quantità di biomasse disponibili. In particolare, per l’impianto in questione, sono stati elaborati dati relativi alle analisi chimiche condotte sulle singole matrici in input all’impianto, sulla base delle quali è possibile dare un primo giudizio di fermentescibilità dei vari substrati e della rispettiva resa in biogas.

Bisphosphonat-assoziierte Osteonekrose der Kiefer : In-vitro-Untersuchungen zur Pathologie und zu möglichen Therapieansätzen

Die Bisphosphonat-assoziierte Osteonekrose der Kiefer (BP-ONJ) stellt eine ernstzunehmende Nebenwirkung der Therapie mit stickstoffhaltigen Bisphosphonaten (N-BP) dar, deren Ätiologie bisher noch nicht vollständig geklärt ist. Da entzündliche Prozesse eine wichtige Rolle zu spielen scheinen, wurde der Einfluss verschiedener Bisphosphonate auf die Mechanismen der granulozytären Erregerabwehr untersucht. Die N-BP Ibandronat, Pamidronat und Zoledronat steigerten die Phagozytose und den oxidativen Burst signifikant. Die fMLP-stimulierte Chemotaxis wurde durch Ibandronat und Zoledronat signifikant reduziert. Das stickstofffreie Clodronat zeigte keinen Effekt auf die getesteten Abwehrmechanismen. Auf der Suche nach therapeutischen Optionen gegen die BP-ONJ wurden die Isoprenoide Farnesol, Geranylgeraniol, Eugenol, Menthol, Limonene und Squalene auf deren Fähigkeit untersucht, die schädigenden Effekte Zoledronats auf verschiedene Zelllinien zu antagonisieren. Geranylgeraniol zeigte als einzige Verbindung eine protektive Wirkung auf gingivale Fibroblasten, Endothelzellen und Osteoblasten. Desweiteren kam es unter Zoledronat zum Anstieg der kleinen GTPasen RhoA und RhoB in gingivalen Fibroblasten. Auch der Gehalt an GTP-gebundenem RhoA stieg nach Zoledronat-Inkubation. Der Einfluss des N-BPs ließ sich auch auf Proteinebene durch Geranylgeraniol antagonisieren und nicht durch Farnesol. Die Tatsache, dass N-BP die granulozytäre Abwehr beeinflussen, unterstützt die Bedeutung keimreduzierender Maßnahmen im Rahmen der Nekroseprophylaxe und -therapie. Außerdem untermauern die Ergebnisse der Arbeit das Potential Geranylgeraniols als neue therapeutische Option.

Development, characterization, and application of flowing atmospheric-pressure afterglow ionization for mass spectrometric analysis of ambient organic aerosols

Addressing current limitations of state-of-the-art instrumentation in aerosol research, the aim of this work was to explore and assess the applicability of a novel soft ionization technique, namely flowing atmospheric-pressure afterglow (FAPA), for the mass spectrometric analysis of airborne particulate organic matter. Among other soft ionization methods, the FAPA ionization technique was developed in the last decade during the advent of ambient desorption/ionization mass spectrometry (ADI–MS). Based on a helium glow discharge plasma at atmospheric-pressure, excited helium species and primary reagent ions are generated which exit the discharge region through a capillary electrode, forming the so-called afterglow region where desorption and ionization of the analytes occurs. Commonly, fragmentation of the analytes during ionization is reported to occur only to a minimum extent, predominantly resulting in the formation of quasimolecular ions, i.e. [M+H]+ and [M–H]– in the positive and the negative ion mode, respectively. Thus, identification and detection of signals and their corresponding compounds is facilitated in the acquired mass spectra. The focus of the first part of this study lies on the application, characterization and assessment of FAPA–MS in the offline mode, i.e. desorption and ionization of the analytes from surfaces. Experiments in both positive and negative ion mode revealed ionization patterns for a variety of compound classes comprising alkanes, alcohols, aldehydes, ketones, carboxylic acids, organic peroxides, and alkaloids. Besides the always emphasized detection of quasimolecular ions, a broad range of signals for adducts and losses was found. Additionally, the capabilities and limitations of the technique were studied in three proof-of-principle applications. In general, the method showed to be best suited for polar analytes with high volatilities and low molecular weights, ideally containing nitrogen- and/or oxygen functionalities. However, for compounds with low vapor pressures, containing long carbon chains and/or high molecular weights, desorption and ionization is in direct competition with oxidation of the analytes, leading to the formation of adducts and oxidation products which impede a clear signal assignment in the acquired mass spectra. Nonetheless, FAPA–MS showed to be capable of detecting and identifying common limonene oxidation products in secondary OA (SOA) particles on a filter sample and, thus, is considered a suitable method for offline analysis of OA particles. In the second as well as the subsequent parts, FAPA–MS was applied online, i.e. for real time analysis of OA particles suspended in air. Therefore, the acronym AeroFAPA–MS (i.e. Aerosol FAPA–MS) was chosen to refer to this method. After optimization and characterization, the method was used to measure a range of model compounds and to evaluate typical ionization patterns in the positive and the negative ion mode. In addition, results from laboratory studies as well as from a field campaign in Central Europe (F–BEACh 2014) are presented and discussed. During the F–BEACh campaign AeroFAPA–MS was used in combination with complementary MS techniques, giving a comprehensive characterization of the sampled OA particles. For example, several common SOA marker compounds were identified in real time by MSn experiments, indicating that photochemically aged SOA particles were present during the campaign period. Moreover, AeroFAPA–MS was capable of detecting highly oxidized sulfur-containing compounds in the particle phase, presenting the first real-time measurements of this compound class. Further comparisons with data from other aerosol and gas-phase measurements suggest that both particulate sulfate as well as highly oxidized peroxyradicals in the gas phase might play a role during formation of these species. Besides applying AeroFAPA–MS for the analysis of aerosol particles, desorption processes of particles in the afterglow region were investigated in order to gain a more detailed understanding of the method. While during the previous measurements aerosol particles were pre-evaporated prior to AeroFAPA–MS analysis, in this part no external heat source was applied. Particle size distribution measurements before and after the AeroFAPA source revealed that only an interfacial layer of OA particles is desorbed and, thus, chemically characterized. For particles with initial diameters of 112 nm, desorption radii of 2.5–36.6 nm were found at discharge currents of 15–55 mA from these measurements. In addition, the method was applied for the analysis of laboratory-generated core-shell particles in a proof-of-principle study. As expected, predominantly compounds residing in the shell of the particles were desorbed and ionized with increasing probing depths, suggesting that AeroFAPA–MS might represent a promising technique for depth profiling of OA particles in future studies.

Characterization of water-soluble organic compounds in ambient aerosol using ultrahigh-resolution elctrospray ionization fourier transform ion cyclotron resonance mass spectrometry.

Atmospheric aerosol water-soluble organic compounds (WSOC) exist in a complex mixture of thousands of organic compounds which may have a significant influence on the climate-relevant properties of the atmospheric aerosol. To understand the potential influences, the ambient aerosol was collected at a nonurban mountainous site near Steamboat Springs, CO. The WSOC fraction was analyzed using positive and negative electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. Approximately 2400 and 4000 molecular formulas were identified from the detected positive and negative ions, respectively. The formulas contained carbon (C), hydrogen (H), oxygen (O), nitrogen (N), and sulfur (S) atoms over the mass range of 100-800 Da in both ionization modes. The number range of double bond equivalents (DBE), the mean O:C, H:C, and oxidation state of carbon for the positive ions were 0 – 18, 0.25 ± 0.15, 1.39 ± 0.29, and -0.89 ± 0.23, respectively. Comparatively, the negative ion values were 0 – 14, 0.53 ± 0.20, 1.48 ± 0.30, and -0.41 ± 0.45, respectively. Overall, the positive ion molecular formulas were less oxygenated than negative ions as seen with the lower O:C and OSc values. Molecular formulas of the positive ions classified as aliphatic, olefinic, and aromatic compound classes based on the aromaticity index values. Aliphatic compounds were the CHNO and CHO formulas that had mean DBE values of about 5 and 3, respectively. However, a majority of the CHOS, CHNOS, and CHS formulas were defined as olefinic compounds and had mean DBE values of about 12, 13, and 10, respectively. Overall, more than half of the assigned molecular formulas contained sulfur and were olefinic to aromatic compounds with a DBE range of 7-18. Source of the unsaturated sulfur containing compounds is currently unknown. Several nitrogen containing compounds were in common with the field and laboratory studies of the biomass burning aerosol and aged secondary organic aerosol products of the limonene ozonolysis.

Assessment of the performance of 3m 3500 organic vapor monitors over extended sampling durations

The purpose of this study was to assess the accuracy and precision of airborne volatile organic compound (VOC) concentrations measured using passive air samplers (3M 3500 organic vapor monitors) over extended sampling durations (9 and 15 days). A total of forty-five organic vapor monitor samples were collected at a State of Texas air monitoring site during two different sampling periods (July/August and November 2008). The results of this study indicate that for most of the tested compounds, there was no significant difference between long-term (9 or 15 days) sample concentrations and the means of parallel consecutive short-term (3 days) sample concentrations. Biases of 9 or 15-day measurements vs. consecutive 3-day measurements showed considerable variability. Those compounds that had percent bias values of <10% are suggested as acceptable for long-term sampling (9 and 15 days). Of the twenty-one compounds examined, 10 compounds are classified as acceptable for long-term sampling; these include m,p-xylene, 1,2,4-trimethylbenzene, n-hexane, ethylbenzene, benzene, toluene, o-xylene, d-limonene, dimethylpentane and methyl tertbutyl ether. The ratio of sampling procedure variability relative to variability within days was approximately 1.89 for both sampling periods for the 3-day vs. 9-day comparisons and approximately 2.19 for both sampling periods for the 3-day vs. 15-day comparisons. Considerably higher concentrations of most VOCs were measured during the November sampling period compared to the July/August period. These differences may be a result of varying meteorological conditions during these two time periods, e.g., the differences in wind direction, and wind speed. Further studies are suggested to further evaluate the accuracy and precision of 3M 3500 organic vapor monitors over extended sampling durations. ^

Isolation and bacterial expression of a sesquiterpene synthase cDNA clone from peppermint (Mentha x piperita, L.) that produces the aphid alarm pheromone (E)-β-farnesene

(E)-β-Farnesene is a sesquiterpene semiochemical that is used extensively by both plants and insects for communication. This acyclic olefin is found in the essential oil of peppermint (Mentha x piperita) and can be synthesized from farnesyl diphosphate by a cell-free extract of peppermint secretory gland cells. A cDNA from peppermint encoding (E)-β-farnesene synthase was cloned by random sequencing of an oil gland library and was expressed in Escherichia coli. The corresponding synthase has a deduced size of 63.8 kDa and requires a divalent cation for catalysis (Km for Mg2+ ≈ 150 μM; Km for Mn2+ ≈ 7 μM). The sesquiterpenoids produced by the recombinant enzyme, as determined by radio-GC and GC-MS, are (E)-β-farnesene (85%), (Z)-β-farnesene (8%), and δ-cadinene (5%) with the native C15 substrate farnesyl diphosphate (Km ≈ 0.6 μM; Vrel = 100) and Mg2+ as cofactor, and (E)-β-farnesene (98%) and (Z)-β-farnesene (2%) with Mn2+ as cofactor (Vrel = 80). With the C10 analog, GDP, as substrate (Km = 1.5 μM; Vrel = 3 with Mg2+ as cofactor), the monoterpenes limonene (48%), terpinolene (15%), and myrcene (15%) are produced.

Assessment and discrimination of odor stimuli in rat olfactory bulb by dynamic functional MRI

Dynamic blood oxygenation level-dependent functional MRI was applied at 7 T in the rat olfactory bulb (OB) with pulsed delivery of iso-amyl acetate (IAA) and limonene. Acquisition times for single-slice and whole OB data were 8 and 32 s, respectively, with spatial resolution of 220 × 220 × 250 μm. On an intrasubject basis, short IAA exposures of 0.6 min separated by 3.5-min intervals induced reproducible spatial activity patterns (SAPs) in the olfactory nerve layer, glomerular layer, and external plexiform layer. During long exposures (≈10 min), the initially dominant dorsal SAPs declined in intensity and area, whereas in some OB regions, the initially weak ventral/lateral SAPs increased first and then decreased. The SAPs of different concentrations were topologically similar, which implies that whereas an odor at various concentrations activates the same subsets of receptor cells, different concentrations are assessed and discriminated by variable magnitudes of laminarspecific activations. IAA and limonene reproducibly activated different subsets of receptor cells with some overlaps. Whereas qualitative topographical agreement was observed with results from other methods, the current dynamic blood oxygenation level-dependent functional MRI results can provide quantitative SAPs of the entire OB.

Chemical characterization of emissions from a municipal solid waste treatment plant

Gaseous emissions are an important problem in municipal solid waste (MSW) treatment plants. The sources points of emissions considered in the present work are: fresh compost, mature compost, landfill leaks and leachate ponds. Hydrogen sulphide, ammonia and volatile organic compounds (VOCs) were analysed in the emissions from these sources. Hydrogen sulphide and ammonia were important contributors to the total emission volume. Landfill leaks are significant source points of emissions of H2S; the average concentration of H2S in biogas from the landfill leaks is around 1700 ppmv. The fresh composting site was also an important contributor of H2S to the total emission volume; its concentration varied between 3.2 and 1.7 ppmv and a decrease with time was observed. The mature composting site showed a reduction of H2S concentration (<0.1 ppmv). Leachate pond showed a low concentration of H2S (in order of ppbv). Regarding NH3, composting sites and landfill leaks are notable source points of emissions (composting sites varied around 30–600 ppmv; biogas from landfill leaks varied from 160 to 640 ppmv). Regarding VOCs, the main compounds were: limonene, p-cymene, pinene, cyclohexane, reaching concentrations around 0.2–4.3 ppmv. H2S/NH3, limonene/p-cymene, limonene/cyclohexane ratios can be useful for analysing and identifying the emission sources.

The reaction of 8-amino-p-menthene derivatives with electrophiles

Attempts to ring-close the nitrogen atom of 8-amino-p-menth-1-ene and of N-substituted 8-amino-p-menth-1-enes onto the C1 - C2 double-bond carbons has led to a range of bicyclo[2.2.2] and bicyclo[3.2.1] products, together with the novel bicyclo[4.3.1]-1,3-oxazepine 9.

Host recognition by a polyphagous lepidopteran (Helicoverpa armigera): primary host plants, host produced volatiles and neurosensory stimulation

An important question in the host-finding behaviour of a polyphagous insect is whether the insect recognizes a suite or template of chemicals that are common to many plants? To answer this question, headspace volatiles of a subset of commonly used host plants (pigeon pea, tobacco, cotton and bean) and nonhost plants (lantana and oleander) of Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) are screened by gas chromatography (GC) linked to a mated female H. armigera electroantennograph (EAG). In the present study, pigeon pea is postulated to be a primary host plant of the insect, for comparison of the EAG responses across the test plants. EAG responses for pigeon pea volatiles are also compared between females of different physiological status (virgin and mated females) and the sexes. Eight electrophysiologically active compounds in pigeon pea headspace are identified in relatively high concentrations using GC linked to mass spectrometry (GC-MS). These comprised three green leaf volatiles [(2E)-hexenal, (3Z)-hexenylacetate and (3Z)-hexenyl-2-methylbutyrate] and five monoterpenes (alpha-pinene,beta-myrcene, limonene, E-beta-ocimene and linalool). Other tested host plants have a smaller subset of these electrophysiologically active compounds and even the nonhost plants contain some of these compounds, all at relatively lower concentrations than pigeon pea. The physiological status or sex of the moths has no effect on the responses for these identified compounds. The present study demonstrates how some host plants can be primary targets for moths that are searching for hosts whereas the other host plants are incidental or secondary targets.

Nano-emulsion production by sonication and microfluidization - A comparison

The efficiency of sonication and microfluidization to produce nano-emulsions were evaluated in this study. The purpose was to produce an oil-in-water nano-emulsion of d-limonene to apply it in the next step for nano-particle encapsulation. In the entrapment and retention of volatiles or for the microencapsulation efficiency, emulsion size is one of the critical factors. In this study, a bench-top sonicator and an air-driven microfluidizer were used to prepare the emulsions. Results show that, while both methods were capable of producing nano-emulsions of the size range of 150-700 nm, the microfluidizer produced emulsions with narrower size distributions and sonication was more convenient in terms of operation and cleaning. In general, the size of the emulsions decreased with increasing sonication time, or the microfluidization pressure and duration. However, for both sonication and microfluidization, optimal conditions were necessary for emulsification beyond which the emulsion sizes would either increase or have little change with further processing.

Structure-reactivity correlations in sulphated-zirconia catalysts for the isomerisation of α-pinene

A range of mesoporous sulphated zirconias with tuneable structural and catalytic properties have been prepared by direct impregnation. The surface sulphate coverage can be readily varied, achieving a maximum value of ∼0.2 monolayers. High-temperature calcination induces the crystallisation of tetragonal zirconia while suppressing the monoclinic phase and enhances surface acidity. Superacid sites only appear above a critical threshold SO4 coverage of 0.08 mL (corresponding to 0.44 wt% total S). Sulphated zirconias show good activity towards α-pinene isomerisation of under mild conditions. Conversion correlates with the number Brønsted acid sites, while the selectivity towards mono- versus polycyclic products depends on the corresponding acid site strength; superacidity promotes limonene formation over camphene.

Support enhanced α-pinene isomerization over HPW/SBA-15

A family of mesoporous SBA-15 supported H3PW12O40 (HPW) catalysts were synthesized by wet-impregnation and compared with fumed silica analogues for the solventless isomerization of α-pinene under mild conditions. Structural and acidic properties of supported HPW materials were characterized by powder XRD, HRTEM, XPS, TGA, N2 porosimetry, DRIFTS, and ammonia and propylamine chemisorption and TPD. The high area, mesoporous SBA-15 architecture facilitates the formation of highly dispersed (isolated or low dimensional) HPW clusters and concomitant high acid site densities (up to 0.54 mmol g−1) relative to fumed silica wherein large HPW crystallites are formed even at low HPW loadings. α-Pinene exhibits a volcano dependence on HPW loading over the SBA-15 support due to competition between the number and accessibility of acid sites to the non-polar reactant, with the superior acid site accessibility for HPW/SBA-15 conferring a 10-fold rate enhancement with respect to HPW/fumed silica and pure HPW. Monocyclic limonene and terpinolene products are favoured over polycyclic camphene and β-pinene by weaker polyoxometallate analogues over SBA-15.

Red mangroves emit hydrocarbons

The objective of this study is to investigate hydrocarbon species and amounts released by red mangrove foliage and determine if these quantities warrant future research on atmospheric chemical processing of these compounds. The field investigation took place during July 2001 at Key Largo, Florida Bay, Florida. Foliage still attached to plants was enclosed in cuvettes while air of known flow rates circulated around leaves to study, hydrocarbon emissions. Cuvette air samples underwent gas chromatographic analyses to determine species and amounts of hydrocarbons released by mangrove foliage. Red mangrove foliage emits isoprene and trace amounts of the monoterpenes of alpha-pinene, beta-pinene, camphene, and d-limonene. The mangrove flowers released these latter compounds in amounts ranging from 0.5 to 10 mg (monoterpene) per gram of dry biomass per hour. These fluxes are normalized to, the foliage temperature of 30 degreesC. When normalized to the foliage temperature of 30 degreesC and light levels of 1000 mumol m(-2) s(-1), isoprene emission rates as high as 0.092 +/- 0.109 mug (isoprene) per gram of dry biomass per hour were measured. Compared to terrestrial forest ecosystems, red mangroves are low isoprene emitters. During peak flowering periods in the summertime, however, red mangroves may emit sufficient amounts of monoterpenes to alter ground-level ozone concentrations and contribute to biogenic aerosol formation.

Fabrication et caractérisation de cellules solaires organiques nanostructurées par la méthode de nanoimpression thermique

La morphologie des couches actives des cellules solaires organiques joue un rôle important sur l’efficacité de conversion de l’énergie solaire en énergie électrique de ces dispositifs. Les hétérojonctions planaires et les hétérojonctions en volume sont les plus communément utilisées. Cependant, la morphologie idéale pour l’efficacité se situerait à mis chemin entre celles-ci. Il s’agit de l’hétérojonction nanostructurée qui augmenterait la surface entre les couches actives de matériaux tout en favorisant le transport des porteurs de charge. L’objectif de ce projet de maîtrise est d’étudier l’impact de l’implantation de nanostructures dans les cellules solaires organiques sur leurs performances photovoltaïques. Pour ce faire, on utilise la méthode de nanoimpression thermique sur le matériau donneur, le P3HT, afin que celui-ci forme une interface nanostructurée avec le matériau accepteur, le PCBM. Pour effectuer les nanoimpressions, des moules en alumine nanoporeuse ont été fabriqués à l’aide du procédé d’anodisation en deux temps développé par Masuda et al. Ces moules ont subi un traitement afin de faciliter leur séparation du P3HT. Les agents antiadhésifs PDMS et FTDS ont été utilisés à cette fin. Les résultats obtenus témoignent de la complexité d’exécution du procédé de nanoimpression. Il a été démontré que la pression appliquée durant le procédé, la tension superficielle des éléments en contact et les dimensions des nanopores des moules sont des paramètres critiques pour le succès des nanoimpressions. Ceux-ci ont donc dû être optimisés de manière à réussir cette opération. Ainsi, des cellules à interface nanostructurée à 25% avec des nanobâtonnets de 35 nm de hauteur ont pu être fabriquées. Les cellules nanostructurées ont démontré une efficacité 2,3 ± 0,6 fois supérieure aux cellules sans nanostructures, dites planaires. D’autre part, un solvant a été proposé pour diminuer l’interdiffusion entre les couches de P3HT et de PCBM pouvant altérer les nanostructures. Ce phénomène bien connu survient lors du dépot de la couche de PCBM avec le dichlorométhane, un solvant orthogonal avec ces matériaux. Des mesures au TOF-SIMS ont démontré que le limonène permet de diminuer l’interdiffusion entre les couches de P3HT et de PCBM, ce qui en fait un meilleur solvant orthogonal que le dichlorométhane.