Effect of rearing techniques and feed composition on productive traits, bird welfare and quality of poultry products

The PhD project was focused on the study of the poultry welfare conditions and improvements. The project work was divided into 3 main research activities. A) Field evaluation of chicken meat rearing conditions kept in intensive farms. Considering the lack of published reports concerning the overall Italian rearing conditions of broiler chickens, a survey was carried out to assess the welfare conditions of broiler reared in the most important poultry companies in Italy to verify if they are in accordance with the advices given in the European proposal COM (2005) 221 final. Chicken farm conditions, carcass lesions and meat quality were investigated. 1. The densities currently used in Italy are in accordance with the European proposal COM 221 final (2005) which suggests to keep broilers at a density lower than 30-32 kg live weight/m2 and to not exceed 38-40 kg live weight/m2. 2. The mortality rates in summer and winter agree with the mortality score calculated following the formula reported in the EU Proposal COM 221 final (2005). 3. The incidence of damaged carcasses was very low and did not seem related to the stocking density. 4. The FPD scores were generally above the maximum limit advised by the EU proposal COM 221 final (2005), although the stocking densities were lower than 30-32 kg live weight per m2. 5. It can be stated that the control of the environmental conditions, particularly litter quality, appears a key issue to control the onset of foot dermatitis. B) Manipulation of several farm parameters, such litter material and depth, stocking density and light regimen to improve the chicken welfare conditions, in winter season. 1. Even though 2 different stocking densities were established in this study, the performances achieved from the chickens were almost identical among groups. 2. The FCR was significantly better in Standard conditions contrarily to birds reared in Welfare conditions with lower stocking density, more litter material and with a light program of 16 hours light and 8 hours dark. 3. In our trial, in Standard groups we observed a higher content of moisture, nitrogen and ammonia released from the litter. Therefore it can be assumed that the environmental characteristics have been positively changed by the improvements of the rearing conditions adopted for Welfare groups. 4. In Welfare groups the exhausted litters of the pens were dryer and broilers showed a lower occurrence of FPD. 5. The prevalence of hock burn lesions, like FPD, is high with poor litter quality conditions. 6. The combined effect of a lower stocking density, a greater amount of litter material and a photoperiod similar to the natural one, have positively influenced the chickens welfare status, as a matter of fact the occurrence of FPD in Welfare groups was the lowest keeping the score under the European threshold of the proposal COM 221 final(2005). C) The purpose of the third research was to study the effect of high or low stocking density of broiler chickens, different types of litter and the adoption of short or long lighting regimen on broiler welfare through the evaluation of their productivity and incidence of foot pad dermatitis during the hot season. 1. The feed efficiency was better for the Low Density than for High Density broilers. 2. The appearance of FPD was not influenced by stocking density. 3. The foot examination revealed that the lesions occurred more in birds maintained on chopped wheat straw than on wood shaving. 4. In conclusion, the adoptions of a short light regimen similar to that occurring in nature during summer reduces the feed intake without modify the growth rate thus improving the feed efficiency. Foot pad lesion were not affected neither by stocking densities nor by light regimens whereas wood shavings exerted a favourable effect in preserving foot pad in good condition. D) A study was carried out to investigate more widely the possible role of 25-hydroxycholecalciferol supplemented in the diet of a laying hen commercial strain (Lohmann brown) in comparison of diets supplemented with D3 or with D3 + 25- hydroxycholecalciferol. Egg traits during a productive cycle as well as the bone characteristics of the layers have been as well evaluated to determine if there the vitamin D3 may enhance the welfare status of the birds. 1. The weight of the egg and of its components is often greater in hens fed a diet enriched with 25-hydroxycholecalciferol. 2. Since eggs of treated groups are heavier and a larger amount of shell is needed, a direct effect on shell strength is observed. 3. At 30 and at 50 wk of age hens fed 25 hydroxycholecalciferol exhibited greater values of bone breaking force. 4. Radiographic density values obtained in the trial are always higher in hens fed with 25-hydroxycholecalciferol of both treatments: supplemented for the whole laying cycle (25D3) or from 40 weeks of age onward (D3+25D3).

Contribution of tectonic processes to the exhumation of the Cycladic blueschist unit, Greece and Turkey

In dieser Studie werden strukturgeologische, metamorphe und geochronologische Daten benutzt, um eine Quantifizierung tektonischer Prozesse vorzunehmen, die für die Exhumierung der Kykladischen Blauschiefereinheit in der Ägäis und der Westtürkei verantwortlich waren. Bei den beiden tektonischen Prozessen handelt es sich um: (1) Abschiebungstektonik und (2) vertikale duktile Ausdünnung. Eine finite Verformungsanalyse an Proben der Kykladischen Blauschiefereinheit ermöglicht eine Abschätzung des Beitrags von vertikaler duktiler Ausdünnung an der gesamten Exhumierung. Kalkulationen mit einem eindimensionalen, numerischen Model zeigt, daß vertikale duktile Ausdünnung nur ca. 10% an der gesamten Exhumierung ausmacht. Kinematische, metamorphe und geochronologische Daten erklären die tektonische Natur und die Evolution eines extensionalen Störungssystems auf der Insel Ikaria in der östlichen Ägäis. Thermobarometrische Daten lassen erkennen, daß das Liegende des Störungssystems aus ca. 15 km Tiefe exhumiert wurde. Sowohl Apatit- und Zirkonspaltspurenalter als auch Apatit (U-Th)/He-Alter zeigen, daß sich das extensionale Störungssystem zwischen 11-3 Ma mit einer Geschwindigkeit von ca. 7-8 km/Ma bewegte. Spät-Miozäne Abschiebungen trugen zur Exhumierung der letzten ~5-15 km der Hochdruckgesteine bei. Ein Großteil der Exhumierung der Kykladischen Blauschiefereinheit muß vor dem Miozän stattgefunden haben. Dies wird durch einen Extrusionskeil erklärt, der ca. 30-35 km der Kykladischen Blauschiefereinheit in der Westtürkei exhumierte. 40Ar/39Ar und 87Rb/86Sr Datierungen an Myloniten des oberen Abschiebungskontakts zwischen der Selçuk Decke und der darunterliegenden Ampelos/Dilek Decke der Kykladischen Blauschiefereinheit als auch des unteren Überschiebungskontakts zwischen der Ampelos/Dilek Decke und den darunterliegenden Menderes Decken zeigt, daß sich beide mylonitische Zonen um ca. ~35 Ma formten, was die Existenz eines Spät-Eozänen/Früh-Oligozänen Extrusionskeils beweist.

Spatial and temporal variability and ecological processes in the epibenthic assemblages of the northern Adriatic Sea

Several coralligenous reefs occur in the soft bottoms of the northern Adriatic continental shelf. Mediterranean coralligenous habitats are characterised by high species diversity and are intrinsically valuable for their biological diversity and for the ecological processes they support. The conservation and management of these habitats require quantifying spatial and temporal variability of their benthic assemblages. This PhD thesis aims to give a relevant contribution to the knowledge of the structure and dynamics of the epibenthic assemblages on the coralligenous subtidal reefs occurring in the northern Adriatic Sea. The epibenthic assemblages showed a spatial variation larger compared to temporal changes, with a temporal persistence of reef-forming organisms. Assemblages spatial heterogeneity has been related to morphological features and geographical location of the reefs, together with variation in the hydrological conditions. Manipulative experiments help to understand the ecological processes structuring the benthic assemblages and maintaining their diversity. In this regards a short and long term experiment on colonization patterns of artificial substrata over a 3-year period has been performed in three reefs, corresponding to the three main types of assemblages detected in the previous study. The first colonisers, largely depending by the different larval supply, played a key role in determining the heterogeneity of the assemblages in the early stage of colonisation. Lateral invasion, from the surrounding assemblages, was the driver in structuring the mature assemblages. These complex colonisation dynamics explained the high heterogeneity of the assemblages dwelling on the northern Adriatic biogenic reefs. The buildup of these coralligenous reefs mainly depends by the bioconstruction-erosion processes that has been analysed through a field experiment. Bioconstruction, largely due to serpulid polychaetes, prevailed on erosion processes and occurred at similar rates in all sites. Similarly, the total energy contents in the benthic communities do not differ among sites, despite being provided by different species. Therefore, we can hypothesise that both bioconstruction processes and energetic storage may be limited by the availability of resources. Finally the major contribution of the zoobenthos compared to the phytobenthos to the total energetic content of assemblages suggests that the energy flow in these benthic habitats is primarily supported by planktonic food web trough the filter feeding invertebrates.

New catalytic processes for the synthesis of adipic acid

The aim of my Ph.D. research was to study the new synthetic ways for the production of adipic acid. Three different pathways were studied: i) oxidation of cyclohexanone with molecular oxygen using Keggin – heteropolycompounds as the catalyst, ii) Baeyer – Villiger oxidation of cyclohexanone with hydrogen peroxide in the presence of two different heterogeneous catalysts, titanium silicalite and silica grafted decatungstate, iii) two step synthesis of adipic acid starting from cyclohexene via 1,2-cyclohexanediol. The first step was catalyzed by H2WO4 in the presence of the phase transfer catalyst, the oxidant was hydrogen peroxide. The second step, oxidation of 1,2 – cyclohexanediol was performed in the presence of oxygen and the heterogeneous catalyst – ruthenium on alumina. The results of my research showed that: i) Oxidation of cyclohexanone with molecular oxygen using Keggin heteropolycompounds is possible, anyway the conversion of ketone is low and the selectivity to adipic acid is lowered by the consecutive reaction to from lower diacids. Moreover it was found out, that there are two mechanisms involved: redox type and radicalic chain-reaction autoxidation. The presence of the different mechanism is influenced by the reaction condition. ii) It is possible to perform thermally activated oxidation of cyclohexanone and obtain non negligible amount of the products (caprolactone and adipic acid). Performing the catalyzed reaction it was demonstrated that the choice of the reaction condition and of the catalyst plays a crucial role in the product selectivity, explaining the discrepancies between the literature and our research. iii) Interesting results can be obtained performing the two step oxidation of cyclohexene via 1,2-cyclohexanediol. In the presence of phase transfer catalyst it is possible to obtain high selectivity to alcohol with stoichiometric amount of oxidant. In the second step of the synthesis, the conversion of alcohol is rather low with modest selectivity to adipic acid

Cache-aware development of high integrity real-time systems

Cost, performance and availability considerations are forcing even the most conservative high-integrity embedded real-time systems industry to migrate from simple hardware processors to ones equipped with caches and other acceleration features. This migration disrupts the practices and solutions that industry had developed and consolidated over the years to perform timing analysis. Industry that are confident with the efficiency/effectiveness of their verification and validation processes for old-generation processors, do not have sufficient insight on the effects of the migration to cache-equipped processors. Caches are perceived as an additional source of complexity, which has potential for shattering the guarantees of cost- and schedule-constrained qualification of their systems. The current industrial approach to timing analysis is ill-equipped to cope with the variability incurred by caches. Conversely, the application of advanced WCET analysis techniques on real-world industrial software, developed without analysability in mind, is hardly feasible. We propose a development approach aimed at minimising the cache jitters, as well as at enabling the application of advanced WCET analysis techniques to industrial systems. Our approach builds on:(i) identification of those software constructs that may impede or complicate timing analysis in industrial-scale systems; (ii) elaboration of practical means, under the model-driven engineering (MDE) paradigm, to enforce the automated generation of software that is analyzable by construction; (iii) implementation of a layout optimisation method to remove cache jitters stemming from the software layout in memory, with the intent of facilitating incremental software development, which is of high strategic interest to industry. The integration of those constituents in a structured approach to timing analysis achieves two interesting properties: the resulting software is analysable from the earliest releases onwards - as opposed to becoming so only when the system is final - and more easily amenable to advanced timing analysis by construction, regardless of the system scale and complexity.

Design and optimization of components and processes for plasma sources in advanced material treatments

The research activities described in the present thesis have been oriented to the design and development of components and technological processes aimed at optimizing the performance of plasma sources in advanced in material treatments. Consumables components for high definition plasma arc cutting (PAC) torches were studied and developed. Experimental activities have in particular focussed on the modifications of the emissive insert with respect to the standard electrode configuration, which comprises a press fit hafnium insert in a copper body holder, to improve its durability. Based on a deep analysis of both the scientific and patent literature, different solutions were proposed and tested. First, the behaviour of Hf cathodes when operating at high current levels (250A) in oxidizing atmosphere has been experimentally investigated optimizing, with respect to expected service life, the initial shape of the electrode emissive surface. Moreover, the microstructural modifications of the Hf insert in PAC electrodes were experimentally investigated during first cycles, in order to understand those phenomena occurring on and under the Hf emissive surface and involved in the electrode erosion process. Thereafter, the research activity focussed on producing, characterizing and testing prototypes of composite inserts, combining powders of a high thermal conductibility (Cu, Ag) and high thermionic emissivity (Hf, Zr) materials The complexity of the thermal plasma torch environment required and integrated approach also involving physical modelling. Accordingly, a detailed line-by-line method was developed to compute the net emission coefficient of Ar plasmas at temperatures ranging from 3000 K to 25000 K and pressure ranging from 50 kPa to 200 kPa, for optically thin and partially autoabsorbed plasmas. Finally, prototypal electrodes were studied and realized for a newly developed plasma source, based on the plasma needle concept and devoted to the generation of atmospheric pressure non-thermal plasmas for biomedical applications.

Fermentative processes for environmental remediation

The growing interest in environmental protection has led to the development of emerging biotechnologies for environmental remediation also introducing the biorefinery concept. This work mainly aimed to evaluate the applicability of innovative biotechnologies for environmental remediation and bioenergy production, throught fermentative processes. The investigated biotechnologies for waste and wastewater treatment and for the valorisation of specific feedstocks and energy recovery, were mainly focused on four research lines. 1. Biotechnology for textile wastewater treatment and water reuse that involving anaerobic and aerobic processes in combination with membrane technologies. Combinations of different treatments were also implemented for water reuse in a textile company. 2. Biotechnology for the treatment of solid waste and leachate in landfill and for biogas production. Landfill operated as Bioreactor with recirculation of the generated leachate was proposed for organic matter biostabilisation and for ammonia removal from leachate by favouring the Anammox process. 3. An innovative two-stage anaerobic process for effective codigestion of waste from the dairy industry, as cheese whey and dairy manure, was studied by combining conventional fermentative processes with a simplified system design for enhancing biomethanisation. 4) The valorisation of the glycerol waste as surplus by-product of the biodiesel industry was investigated via microbial conversion to value-added chemicals, as 1,3-propanediol. The investigated fermentative processes have been successfully implemented and reached high yields of the produced bio-chemical. The studied biotechnological systems proved to be feasible for environmental remediation and bioenergy and chemicals production.

Proteins control in biomineralization processes of the freshwater pearl mussel Hyriopsis cumingii

Pearls are an amazing example of calcium carbonate biomineralization. They show a classic brick and mortar internal structure in which the predominant inorganic part is composed by aragonite and vaterite tablets. The organic matrix is disposed in concentric layers tightly associated to the mineral structures. Freshwater cultivate pearls (FWCPs) and shells nacreous layers of the Chinese mussel Hyriopsis cumingii were demineralized using an ion exchange resin in order to isolate the organic matrix. From both starting materials a soluble fraction was obtained and further analyzed. The major component of the soluble extracts was represented by a similar glycoprotein having a molecular weight of about 48 kDa in pearls and 44 kDa in shells. Immunolocalization showed their wide distribution in the organic sheet surrounding calcium carbonate tablets of the nacre and in the interlamellar and intertabular matrix. These acidic glycoprotein also contained inside the aragonite platelets, are direct regulators during biomineralization processes, participating to calcium carbonate precipitation since the nucleation step. Selective calcium carbonate polymorph precipitation was performed using the two extracts. The polysaccharides moiety was demonstrate to be a crucial factor in polymorphs selection. In particular, the higher content in sugar groups found in pearls extract was responsible of stabilization of the high energetic vaterite during the in vitro precipitation assay; while irregular calcite was obtained using shells protein. Furthermore these polypeptides showed a carbonic anhydrase activity that, even if not directly involved in polymorphs determination, is an essential regulator in CaCO3 formation by means of carbonate anions production. The structural and functional characterization of the proteins included in biocomposites, gives important hints for understanding the complicated process of biomineralization. A better knowledge of this natural mechanism can offer new strategies for producing environmental friendly materials with controlled structures and enhanced chemical-physical features.

Exploring physical processes related to past climate proxies: lake sediments and stable water isotopes

Proxy data are essential for the investigation of climate variability on time scales larger than the historical meteorological observation period. The potential value of a proxy depends on our ability to understand and quantify the physical processes that relate the corresponding climate parameter and the signal in the proxy archive. These processes can be explored under present-day conditions. In this thesis, both statistical and physical models are applied for their analysis, focusing on two specific types of proxies, lake sediment data and stable water isotopes.rnIn the first part of this work, the basis is established for statistically calibrating new proxies from lake sediments in western Germany. A comprehensive meteorological and hydrological data set is compiled and statistically analyzed. In this way, meteorological times series are identified that can be applied for the calibration of various climate proxies. A particular focus is laid on the investigation of extreme weather events, which have rarely been the objective of paleoclimate reconstructions so far. Subsequently, a concrete example of a proxy calibration is presented. Maxima in the quartz grain concentration from a lake sediment core are compared to recent windstorms. The latter are identified from the meteorological data with the help of a newly developed windstorm index, combining local measurements and reanalysis data. The statistical significance of the correlation between extreme windstorms and signals in the sediment is verified with the help of a Monte Carlo method. This correlation is fundamental for employing lake sediment data as a new proxy to reconstruct windstorm records of the geological past.rnThe second part of this thesis deals with the analysis and simulation of stable water isotopes in atmospheric vapor on daily time scales. In this way, a better understanding of the physical processes determining these isotope ratios can be obtained, which is an important prerequisite for the interpretation of isotope data from ice cores and the reconstruction of past temperature. In particular, the focus here is on the deuterium excess and its relation to the environmental conditions during evaporation of water from the ocean. As a basis for the diagnostic analysis and for evaluating the simulations, isotope measurements from Rehovot (Israel) are used, provided by the Weizmann Institute of Science. First, a Lagrangian moisture source diagnostic is employed in order to establish quantitative linkages between the measurements and the evaporation conditions of the vapor (and thus to calibrate the isotope signal). A strong negative correlation between relative humidity in the source regions and measured deuterium excess is found. On the contrary, sea surface temperature in the evaporation regions does not correlate well with deuterium excess. Although requiring confirmation by isotope data from different regions and longer time scales, this weak correlation might be of major importance for the reconstruction of moisture source temperatures from ice core data. Second, the Lagrangian source diagnostic is combined with a Craig-Gordon fractionation parameterization for the identified evaporation events in order to simulate the isotope ratios at Rehovot. In this way, the Craig-Gordon model can be directly evaluated with atmospheric isotope data, and better constraints for uncertain model parameters can be obtained. A comparison of the simulated deuterium excess with the measurements reveals that a much better agreement can be achieved using a wind speed independent formulation of the non-equilibrium fractionation factor instead of the classical parameterization introduced by Merlivat and Jouzel, which is widely applied in isotope GCMs. Finally, the first steps of the implementation of water isotope physics in the limited-area COSMO model are described, and an approach is outlined that allows to compare simulated isotope ratios to measurements in an event-based manner by using a water tagging technique. The good agreement between model results from several case studies and measurements at Rehovot demonstrates the applicability of the approach. Because the model can be run with high, potentially cloud-resolving spatial resolution, and because it contains sophisticated parameterizations of many atmospheric processes, a complete implementation of isotope physics will allow detailed, process-oriented studies of the complex variability of stable isotopes in atmospheric waters in future research.rn

Numerical simulations of microphysical processes in pyro-convective clouds

Hochreichende Konvektion über Waldbränden ist eine der intensivsten Formen von atmosphärischer Konvektion. Die extreme Wolkendynamik mit hohen vertikalen Windgeschwindigkeiten (bis 20 m/s) bereits an der Wolkenbasis, hohen Wasserdampfübersättigungen (bis 1%) und die durch das Feuer hohen Anzahlkonzentration von Aerosolpartikeln (bis 100000 cm^-3) bilden einen besonderen Rahmen für Aerosol-Wolken Wechselwirkungen.Ein entscheidender Schritt in der mikrophysikalischen Entwicklung einer konvektiven Wolke ist die Aktivierung von Aerosolpartikeln zu Wolkentropfen. Dieser Aktivierungsprozess bestimmt die anfängliche Anzahl und Größe der Wolkentropfen und kann daher die Entwicklung einer konvektiven Wolke und deren Niederschlagsbildung beeinflussen. Die wichtigsten Faktoren, welche die anfängliche Anzahl und Größe der Wolkentropfen bestimmen, sind die Größe und Hygroskopizität der an der Wolkenbasis verfügbaren Aerosolpartikel sowie die vertikale Windgeschwindigkeit. Um den Einfluss dieser Faktoren unter pyro-konvektiven Bedingungen zu untersuchen, wurden numerische Simulationen mit Hilfe eines Wolkenpaketmodells mit detaillierter spektraler Beschreibung der Wolkenmikrophysik durchgeführt. Diese Ergebnisse können in drei unterschiedliche Bereiche abhängig vom Verhältnis zwischen vertikaler Windgeschwindigkeit und Aerosolanzahlkonzentration (w/NCN) eingeteilt werden: (1) ein durch die Aerosolkonzentration limitierter Bereich (hohes w/NCN), (2) ein durch die vertikale Windgeschwindigkeit limitierter Bereich (niedriges w/NCN) und (3) ein Übergangsbereich (mittleres w/NCN). Die Ergebnisse zeigen, dass die Variabilität der anfänglichen Anzahlkonzentration der Wolkentropfen in (pyro-) konvektiven Wolken hauptsächlich durch die Variabilität der vertikalen Windgeschwindigkeit und der Aerosolkonzentration bestimmt wird. rnUm die mikrophysikalischen Prozesse innerhalb der rauchigen Aufwindregion einer pyrokonvektiven Wolke mit einer detaillierten spektralen Mikrophysik zu untersuchen, wurde das Paketmodel entlang einer Trajektorie innerhalb der Aufwindregion initialisiert. Diese Trajektore wurde durch dreidimensionale Simulationen eines pyro-konvektiven Ereignisses durch das Model ATHAM berechnet. Es zeigt sich, dass die Anzahlkonzentration der Wolkentropfen mit steigender Aerosolkonzentration ansteigt. Auf der anderen Seite verringert sich die Größe der Wolkentropfen mit steigender Aerosolkonzentration. Die Reduzierung der Verbreiterung des Tropfenspektrums stimmt mit den Ergebnissen aus Messungen überein und unterstützt das Konzept der Unterdrückung von Niederschlag in stark verschmutzen Wolken.Mit Hilfe des Models ATHAM wurden die dynamischen und mikrophysikalischen Prozesse von pyro-konvektiven Wolken, aufbauend auf einer realistischen Parametrisierung der Aktivierung von Aerosolpartikeln durch die Ergebnisse der Aktivierungsstudie, mit zwei- und dreidimensionalen Simulationen untersucht. Ein modernes zweimomenten mikrophysikalisches Schema wurde in ATHAM implementiert, um den Einfluss der Anzahlkonzentration von Aerosolpartikeln auf die Entwicklung von idealisierten pyro-konvektiven Wolken in US Standardamtosphären für die mittleren Breiten und den Tropen zu untersuchen. Die Ergebnisse zeigen, dass die Anzahlkonzentration der Aerosolpartikel die Bildung von Regen beeinflusst. Für geringe Aerosolkonzentrationen findet die rasche Regenbildung hauptsächlich durch warme mikrophysikalische Prozesse statt. Für höhere Aerosolkonzentrationen ist die Eisphase wichtiger für die Bildung von Regen. Dies führt zu einem verspäteten Einsetzen von Niederschlag für verunreinigtere Atmosphären. Außerdem wird gezeigt, dass die Zusammensetzung der Eisnukleationspartikel (IN) einen starken Einfluss auf die dynamische und mikrophysikalische Struktur solcher Wolken hat. Bei sehr effizienten IN bildet sich Regen früher. Die Untersuchung zum Einfluss des atmosphärischen Hintergrundprofils zeigt eine geringe Auswirkung der Meteorologie auf die Sensitivität der pyro-konvektiven Wolken auf diernAerosolkonzentration. Zum Abschluss wird gezeigt, dass die durch das Feuer emittierte Hitze einen deutlichen Einfluss auf die Entwicklung und die Wolkenobergrenze von pyro-konvektive Wolken hat. Zusammenfassend kann gesagt werden, dass in dieser Dissertation die Mikrophysik von pyrokonvektiven Wolken mit Hilfe von idealisierten Simulation eines Wolkenpaketmodell mit detaillierte spektraler Mikrophysik und eines 3D Modells mit einem zweimomenten Schema im Detail untersucht wurde. Es wird gezeigt, dass die extremen Bedingungen im Bezug auf die vertikale Windgeschwindigkeiten und Aerosolkonzentrationen einen deutlichen Einfluss auf die Entwicklung von pyro-konvektiven Wolken haben.

Innovative processes for syngas production

The research of new advanced processes for syngas production is a part of a European project for the production of a new Gas to Liquid Process (NextGTL). The crucial points in the production of GTL process are the energy required for the air separation used in autothermal reforming or the heat required for steam reforming and the efficiency in carbon utilization. Therefore a new multistep oxy-reforming process scheme was developed at lower temperature with intermediate H2 membrane separation to improve the crucial parameter. The process is characterized by a S/C of 0.7 and O2/C of 0.21 having a smoothed temperature profile in which kinetic regime is easily obtained. Active catalysts for low temperature oxy-reforming process have been studied working at low pressure to discriminate among the catalyst and at high pressure to prove it on industrial condition. It allows the selection of the Rh as active phase among single and bimetallic VIII group metal. The study of the matrix composition and thermal treatment has been carried out on Rh-Mg/Al hydrotalcite selected as reference catalyst. The research to optimize the catalyst lead to enhanced performances through the identification of a limitation of the Rh reduction from the oxides matrix as key point to increase the Rh performances. The Rh loading have been studied to allow the catalyst scale up for pilot process in Chieti in a shape of Rh-HT on honeycomb ceramic material. The developed catalyst has enhanced methane conversion in a inch diameter monolith reactor if compared with the semi-industrial catalyst chosen in the project as the best reference.

Model reduction of stochastic groundwater flow and transport processes

This work presents a comprehensive methodology for the reduction of analytical or numerical stochastic models characterized by uncertain input parameters or boundary conditions. The technique, based on the Polynomial Chaos Expansion (PCE) theory, represents a versatile solution to solve direct or inverse problems related to propagation of uncertainty. The potentiality of the methodology is assessed investigating different applicative contexts related to groundwater flow and transport scenarios, such as global sensitivity analysis, risk analysis and model calibration. This is achieved by implementing a numerical code, developed in the MATLAB environment, presented here in its main features and tested with literature examples. The procedure has been conceived under flexibility and efficiency criteria in order to ensure its adaptability to different fields of engineering; it has been applied to different case studies related to flow and transport in porous media. Each application is associated with innovative elements such as (i) new analytical formulations describing motion and displacement of non-Newtonian fluids in porous media, (ii) application of global sensitivity analysis to a high-complexity numerical model inspired by a real case of risk of radionuclide migration in the subsurface environment, and (iii) development of a novel sensitivity-based strategy for parameter calibration and experiment design in laboratory scale tracer transport.

Copper and zinc stable isotope ratios as tracers of biogeochemical processes, sources and transport of Cu and Zn in soils

Copper and Zn are essential micronutrients for plants, animals, and humans; however, they may also be pollutants if they occur at high concentrations in soil. Therefore, knowledge of Cu and Zn cycling in soils is required both for guaranteeing proper nutrition and to control possible risks arising from pollution.rnThe overall objective of my study was to test if Cu and Zn stable isotope ratios can be used to investigate into the biogeochemistry, source and transport of these metals in soils. The use of stable isotope ratios might be especially suitable to trace long-term processes occurring during soil genesis and transport of pollutants through the soil. In detail, I aimed to answer the questions, whether (1) Cu stable isotopes are fractionated during complexation with humic acid, (2) 65Cu values can be a tracer for soil genetic processes in redoximorphic soils (3) 65Cu values can help to understand soil genetic processes under oxic weathering conditions, and (4) 65Cu and 66Zn values can act as tracers of sources and transport of Cu and Zn in polluted soils.rnTo answer these questions, I ran adsorption experiments at different pH values in the laboratory and modelled Cu adsorption to humic acid. Furthermore, eight soils were sampled representing different redox and weathering regimes of which two were influenced by stagnic water, two by groundwater, two by oxic weathering (Cambisols), and two by podzolation. In all horizons of these soils, I determined selected basic soil properties, partitioned Cu into seven operationally defined fractions and determined Cu concentrations and Cu isotope ratios (65Cu values). Finally, three additional soils were sampled along a deposition gradient at different distances to a Cu smelter in Slovakia and analyzed together with bedrock and waste material from the smelter for selected basic soil properties, Cu and Zn concentrations and 65Cu and 66Zn values.rnMy results demonstrated that (1) Copper was fractionated during adsorption on humic acid resulting in an isotope fractionation between the immobilized humic acid and the solution (65CuIHA-solution) of 0.26 ± 0.11‰ (2SD) and that the extent of fractionation was independent of pH and involved functional groups of the humic acid. (2) Soil genesis and plant cycling causes measurable Cu isotope fractionation in hydromorphic soils. The results suggested that an increasing number of redox cycles depleted 63Cu with increasing depth resulting in heavier 65Cu values. (3) Organic horizons usually had isotopically lighter Cu than mineral soils presumably because of the preferred uptake and recycling of 63Cu by plants. (4) In a strongly developed Podzol, eluviation zones had lighter and illuviation zones heavier 65Cu values because of the higher stability of organo-65Cu complexes compared to organo-63Cu complexes. In the Cambisols and a little developed Podzol, oxic weathering caused increasingly lighter 65Cu values with increasing depth, resulting in the opposite depth trend as in redoximorphic soils, because of the preferential vertical transport of 63Cu. (5) The 66Zn values were fractionated during the smelting process and isotopically light Zn was emitted allowing source identification of Zn pollution while 65Cu values were unaffected by the smelting and Cu emissions isotopically indistinguishable from soil. The 65Cu values in polluted soils became lighter down to a depth of 0.4 m indicating isotope fractionation during transport and a transport depth of 0.4 m in 60 years. 66Zn values had an opposite depth trend becoming heavier with depth because of fractionation by plant cycling, speciation changes, and mixing of native and smelter-derived Zn. rnCopper showed measurable isotope fractionation of approximately 1‰ in unpolluted soils, allowing to draw conclusions on plant cycling, transport, and redox processes occurring during soil genesis and 65Cu and 66Zn values in contaminated soils allow for conclusions on sources (in my study only possible for Zn), biogeochemical behavior, and depth of dislocation of Cu and Zn pollution in soil. I conclude that stable Cu and Zn isotope ratios are a suitable novel tool to trace long-term processes in soils which are difficult to assess otherwise.rn

Giunzione mediante laser di materiali difficili, ibridi ed a struttura cellulare

Lo studio presentato in questa sede concerne applicazioni di saldatura LASER caratterizzate da aspetti di non-convenzionalità ed è costituito da tre filoni principali. Nel primo ambito di intervento è stata valutata la possibilità di effettuare saldature per fusione, con LASER ad emissione continua, su pannelli Aluminum Foam Sandwich e su tubi riempiti in schiuma di alluminio. Lo studio ha messo in evidenza numerose linee operative riguardanti le problematiche relative alla saldatura delle pelli esterne dei componenti ed ha dimostrato la fattibilità relativa ad un approccio di giunzione LASER integrato (saldatura seguita da un post trattamento termico) per la realizzazione della giunzione completa di particolari tubolari riempiti in schiuma con ripristino della struttura cellulare all’interfaccia di giunzione. Il secondo ambito di intervento è caratterizzato dall’applicazione di una sorgente LASER di bassissima potenza, operante in regime ad impulsi corti, nella saldatura di acciaio ad elevato contenuto di carbonio. Lo studio ha messo in evidenza come questo tipo di sorgente, solitamente applicata per lavorazioni di ablazione e marcatura, possa essere applicata anche alla saldatura di spessori sub-millimetrici. In questa fase è stato messo in evidenza il ruolo dei parametri di lavoro sulla conformazione del giunto ed è stata definita l’area di fattibilità del processo. Lo studio è stato completato investigando la possibilità di applicare un trattamento LASER dopo saldatura per addolcire le eventuali zone indurite. In merito all’ultimo ambito di intervento l’attività di studio si è focalizzata sull’utilizzo di sorgenti ad elevata densità di potenza (60 MW/cm^2) nella saldatura a profonda penetrazione di acciai da costruzione. L’attività sperimentale e di analisi dei risultati è stata condotta mediante tecniche di Design of Experiment per la valutazione del ruolo preciso di tutti i parametri di processo e numerose considerazioni relative alla formazione di cricche a caldo sono state suggerite.

Catalysts and processes for next-generation H2 production

The present study is focused on the development of new VIII group metal on CeO2 – ZrO2 (CZO) catalyst to be used in reforming reaction for syngas production. The catalyst are tested in the oxyreforming process, extensively studied by Barbera [44] in a new multistep process configuration, with intermediate H2 membrane separation, that can be carried out at lower temperature (750°C) with respect the reforming processes (900 – 1000°C). In spite of the milder temperatures, the oxy-reforming conditions (S/C = 0.7; O2/C = 0.21) remain critical regarding the deactivation problems mainly deriving from thermal sintering and carbon formation phenomena. The combination of the high thermal stability characterizing the ZrO2, with the CeO2 redox properties, allows the formation of stable mixed oxide system with high oxygen mobility. This feature can be exploited in order to contrast the carbon deposition on the active metal surface through the oxidation of the carbon by means of the mobile oxygen atoms available at the surface of the CZO support. Ce0.5Zr0.5O2 is the phase claimed to have the highest oxygen mobility but its formation is difficult through classical synthesis (co-precipitation), hence a water-in-oil microemulsion method is, widely studied and characterized. Two methods (IWI and bulk) for the insertion of the active metal (Rh, Ru, Ni) are followed and their effects, mainly related to the metal stability and dispersion on the support, are discussed, correlating the characterization with the catalytic activity. Different parameters (calcination and reduction temperatures) are tuned to obtain the best catalytic system both in terms of activity and stability. Interesting results are obtained with impregnated and bulk catalysts, the latter representing a new class of catalysts. The best catalysts are also tested in a low temperature (350 – 500°C) steam reforming process and preliminary tests with H2 membrane separation have been also carried out.