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In the framework of on going research projects and programmes (i.e., GMOS, UNEP F&T) aiming to develop advanced sensors for major atmospheric pollutants, and having as overarching goal to assure a full operational capability of global observing systems for persistent pollutants such as mercury a novel sensors with promising sensing features for environmental applications have been designed and tested. The aim of this paper is to present a novel sensor based on nanostructured hybrid materials capable of entrapping and detecting Gaseous Elemental Mercury (GEM) at trace levels once the photocatalysis is activated with UV light irradiation. This nanostructured hybrid material is obtained by combining composite nanofibrous electrospun scaffolds of titania and gold nanoparticles. The size and the shape of these nanostructures have been demonstrated to be key parameters in defining the properties of the resulting sensors, because of the strict relationship between the surface and the bulk of the sensing material which is extremely reduced in size. The increase in the number of binding sites has been confirmed to be a successful strategy to ensure sensitivity at trace level. SEM, AFM, TEM and HR-TEM analyses have been performed to characterise the morphology and the nano-sized structure of these composite materials. Different electrical and sensing features of the resulting chemosensors have been achieved by tuning fibres roughness and gold nanoparticle size. A suitable measuring chamber for mercury detection have been designed and developed in order to improve the sensing feature of the sensor. Thus few minutes of air sampling were sufficient to detect the concentration of mercury in the air without using traps (LOD ? 1 ppb). Longer measurements allowed the sensor to detect lower concentrations of GEM (tens of ppt). A short thermal treatment (450°C, 3min) was necessary to completely desorb mercury from AuNPs. The resulting chemosensors are expected to be very stable over time, robust and resistant to the interference that may be caused by common solvents and by VOCs commonly present in ambient air.

Electrospinning technology has been proven to be an intriguing strategy to create highly performing nanostructured sensors [1] able to reveal toxic gases and VOCs in the environment. Therefore various nanocomposite fibrous layers have been synthesized and investigated for their applications as active materials for gas sensors [2]. The design of nanocomposite layers for sensor applications takes in consideration several factors, such as the arrangement of both materials within the fibres, their interfacial characteristics, electrical and optical performances, thermal and mechanical stability, etc., all of which depending significantly on each materials features and deposition process parameters. In the present study, titania nanofibrous layers were decorated with fluorescent nanoparticles (QDs) and then investigated as potential chemical sensors, at solid state, for detecting toxic gases. TiO2 sounds a suitable scaffold since it is a photoactive semiconductor material easily tuning by incorporating dye molecules and semiconductor nanocrystals [3,4]. Therefore first, fluorescent (CdSe)ZnS core-shell quantum dots were synthesized, according to literature, by decomposing organometallic precursors at high temperature in a suitable coordinating solvent [5] and then functionalized with a stabilizing organic shell, trioctylphosphine oxide (TOPO). Second, the resulting QDs (~6nm) were deposited on electrospun titania nanofibres (anatase) both by dipping (physical interaction) and by in situ chemical functionalization of the fibres with bi-functional linkers (containing -COOH and -SH), capable of immobilizing the nanoparticles. Their different arrangements over the fibres were characterized by AFM (Atomic Force Microscopy) and HR-TEM (High-Resolution Transmission Electron Microscopy), and their optical performances were investigated by spectrophotometry and spectrofluorometry as well as fluorescence microscopy. Since fibres were grown on the transducers (interdigitated electrodes of Pt/Ti) and the following functionalization occurred in situ, the resulting fibres were simultaneously investigated as potential optical sensors due to the quenching of their fluorescence after gas interaction and as photoconductive sensors at room temperature due to the changes of their photoconductivity (UV-LED 365 nm) under known concentrations of a toxic gas (NH3).

Currently, the production-to-consumption food system is a multifaceted process that includes processing, handling and distribution, and allows to get food largely safe, tasty, nutritious, abundant, diverse, convenient, less costly and more accessible than ever. Along the path of food from producers to vendors until consumers, its quality can be altered, for instance, upon microbial and chemical contamination and unsuitable storage conditions. As a consequence, the offer by producers and vendors of tasty, fresh and safe foods to consumers is a crucial goal to preserve market sustainability on one side and people health on the other side. For these reasons, each step of this path must fulfil the requirements fixed by government authorities and referred to stringent standards and benchmarks to ensure food safety until use. For the assessment of optimal quality assurance of foods, manufacturers need cost-effective and rapid methods, preferably working on-line, performing measurements of the chemical, physical and microbiological properties of raw materials, transformed foods along the process streams and end products. The monitoring during food processing prevents expenses of either reworking or disposal of out-of-specification (low-quality) products. The recent advances in nanotechnology-based molecular sensing [1] have been addressed to develop novel sensors and sophisticated sensing systems to be potentially used in each step of the production-transportation-storage-processing-distribution food chain. The unique electric, optical and chemical properties of nanomaterials allow their employment, for example, in arrays of sensors and biosensors, electronic noses and tongues [2], test-strips, cantilevers, radio-frequency identification (RFID) tags, surface-enhanced Raman scattering (SERS) nanoprobes, chemical sensors embedded in packaging and naked-eye colorimetric sensors, to detect the presence of various adulterations in complex food matrices and to speed up the tests and improve the accuracy of food regulatory agencies. Nanomaterials such as metal, metal oxide and magnetic nanoparticles (NPs), carbon nanotubes (CNTs), graphene, MeOx/Me nanorods, quantum dots (QDs), nanowires and composite nanofibres are playing a noticeable role in designing sensors and sensing platforms with lower detection limits and improving the performances of conventional methods for food analyses. In food quality testing procedures and devices, nanomaterials provide several advantages, over conventional materials, such as ultra-sensitivity, selectivity, multiple targeting, portability, reproducible data processing, packaging conformability. In the present review, some remarkable achievements are discussed recently obtained in applications of nanotechnologies to food quality maintenance and monitoring, and the most promising results attained by using electrospun-based sensors are highlighted [3]. References [1]. Source: Nanotechnology in food quality control: Preventing food from biting back http://www.nanowerk.com/spotlight/spotid=35646.php [2]. G Olafsdottir, P Nesvadba, C Di Natale, M Careche, J Oehlenschläger, SV Tryggvadottir, R Schubring, M Kroeger, K Heia, M Esaiassen, A Macagnano, BM Jørgensen, Multisensors for fish quality determination, Trends in Food Science & Technology 15 2004 86-93. [3]. A Macagnano, E. Zampetti, E Kny, Electrospinning for high performance sensors, in Nanoscience and Technology Series, Springer 2015, pp. 1-329. ISBN: 978-3-319-14405-4 (Print) 978-3-319-14406-1 (Online), DOI.10.1007/978-3-319-14406-1

Deliverable 1.2.10 provides a report on the development of a prototype sensor for atmospheric mercury measurements in ambient air, which will be tested and validated later on in this project employing the GMOS sites. A series of fabrics based on nanofibers of titanium oxide properly functionalised with gold nanoclusters have been prepared, since similar structures exhibit the highest Hg0 removal efficiency (100%) when compared to other nanofibrous systems. We focused in particular on the development of components for a TGM passive sampler including a collection surface, diffusive housing, and an external shield. Important goals for the final product were a system inexpensive to manufacture, simple to analyze, easily shipped and deployed, which could be handled and transported without contamination.

Recently, global traceability and measurements of Hg have been addressed with a network approach using automated and/or semi-automated systems for sampling and detection of Hg in air and wet deposition. Based on the commonly used procedures for the determination of Hg in ambient air within the GMOS global network, the corresponding costs to run more than 40 monitoring sites are extremely high, especially in remote regions such as Antarctica or in pristine areas that do not have a basic infrastructure (i.e., no clean labs, poor power supply) as well as trained operators. On long term, the management sustainability of global or continental scale monitoring networks for measuring Hg in air samples depends very much on our ability to develop advanced sensor capable to measure total Hg (THg) or even better speciated mercury concentrations. These advanced sensors should be robust, traceable and should not require gas carrier, significant energy supply and highly qualified technical expertise. Having the above in mind, our goal is to present preliminary results on research strategies adopted for the development of newly sensor technologies with the aim to develop a prototype sensor based on the advantage of not requiring any pre-treatment of samples, it is very sensitive, can reach ultra trace level, does not require significant power supply and is not expensive. The Deliverable 1.2.11 provides a report on the development of sensor technologies for continuous and/or semi-continuous atmospheric mercury measurements of Hg(0)/GEM, Hg(II)/GOM in ambient air.

Mercury (Hg) is a global pollutant of concern due to its toxicity and bioaccumulation in aquatic food chains with serious consequences on human and wildlife health. Although in the past two decades a number of Hg monitoring sites have been established in Europe, Canada, USA and Asia as part of regional network the need of long-term atmospheric Hg monitoring and additional ground-based monitoring sites have constantly been highlighted to generate consistent datasets necessary for offering new insight and information about the global scale trends of atmospheric Hg emissions and deposition. A coordinated global observational network for atmospheric Hg has been established in the framework of the Global Mercury Observation System (GMOS) project (FP7) in 2010 with the aim to provide high-quality Hg datasets in the Northern and Southern Hemispheres for a comprehensive assessment of atmospheric Hg concentrations and their dependence on meteorology, long-range atmospheric transport and atmospheric emissions on a global scale. Hg measurements were carried out using high-quality techniques by harmonizing the chosen measurement techniques with those being performed at existing monitoring stations around the world. Special attention was paid in respect to protocols harmonization, data quality collection and data management in order to assure a full comparability of site specific observational datasets. During the planning and implementation stage of the GMOS global network, harmonized Standard Operating Procedures (SOPs) as well as common Quality Assurance/Quality Control (QA/QC) protocols have been indeed addressed in accordance with the measurement practice adopted in well-established regional monitoring networks and based on the most recent literature. A great effort was in particular made to implement a centralized system (termed GMOS-Data Quality Management, G-DQM) able to acquire atmospheric Hg data in near real-time and, furthermore, to assure and control quality of collected Hg datasets. This system introduced a big novelty for data control programs, consisting in a service approach that facilitate real-time adaptive monitoring procedures, thus being essential in preventing the production of poor-quality data. The Deliverable 1.2.5 provides a report detailing GMOS methods adopted within the global network.

Electrospun titania nanofibres combine large surface area with intrinsic semiconducting properties, thus providing great potential to such material for various applications. Anatase is the most photoactive phase of titania, and is then eligible for sensor, optoelectronic and catalytic devices, playing also a crucial role in disinfection applications and environmental remediation processes. As n-type semiconductor, titania nanofibres have been widely investigated and used for detecting several atmospheric pollutants at both high and room temperature, after the addition of organic and inorganic dopants [1]. Recently, Au/TiO2 nanocomposite layers have been investigated by the authors as potential conductive sensors to detect elemental mercury at room temperature in the atmosphere [2]. Because of their high sensitivity combined with low maintenance, easy of handling and low fabrication costs, such sensors resulted as promising candidates to detect mercury in proximity of polluted areas. In that study, the photocatalytic properties of titania allowed gold nanoparticles to selectively grow on the nanofibrous scaffold from HAuCl4 (tetrachloroauric acid) as a precursor, under UV-light irradiation. The results obtained in that study, however, were far enough from commercial analytical devices, which detect traces of mercury (< 0.1 ng/m3) in a few minutes (~5min). A great exposure time was necessary, indeed, to trap enough mercury in order to get observable electrical signals. In the present study, the amazing properties of titania were further employed in distinct strategies to improve the sensing features of the material and the resulting sensors. In the former strategy, rougher nanofibrous layers of titania were created, in order to greatly increase the number of gold nucleation sites. This finding was achieved by adding an aliquot of a non-ionic surfactant (Triton X) in the freshly prepared electrospun solution. SEM, AFM, TEM and HR-TEM analyses were carried out to characterise the morphology and the nano-sized structures of such composite nanofibres. It is known that the sensor response depends on the number of mercury atoms adsorbed on its sensitive surface. The increase in the global number of binding sites on the electrospun fabric was, then, expected to be successful in improving the sensor performances. In the latter strategy, UV-light (365 nm) was applied on the nanocomposite material in order to enable titania to cooperate with gold in mercury entrapment [3] and then enlarge the properties of the sensing layer. Optical and electrical features of both rough and UV-treated Au/TiO2 layers are here reported and discussed.

The environmental monitoring sounds as the prerequisite for the handling of the environmental pollution, strictly linked to the strategies of cleaning and remediation. In order to achieve this objective with affordable investment and running costs, there is need to develop advanced sensors for air quality monitoring and more in general for environmental monitoring capable to produce data that are comparable to those provided by adopting standard methods and technologies. Similarly, the conventional strategies used to clean the environmental compartments need to be improved in efficiency and convenience, using materials and technologies capable of inflicting the minimal or no harm at all upon ecosystems. Due to the huge advance of nanoscience and nanotechnology over the last two decades, great progress has been made not only in nanomaterials engineering and characterisation, but also in their functional applications. Because of their reduced size and large radii of curvature, the nanomaterials have a surface that is particularly reactive (mainly due to the high density of low-coordinated atoms at the surface, edges and defects). These unique properties can be applied to degrade and scavenge pollutants in air and water. Among nanostructured materials, nanofibrous structures offer unique properties, such as a high specific surface area (depending on the diameter of fibres and intra-fibre porosity), good interconnectivity of the pores and the potential to combine active chemistry or functionality at a nanoscale10. The working principle of these nanomaterials involved in remediation, may be used to design and fabricate nanosensors with improved detection of the pollutants. Functionalised and engineered nanofibres have been investigated and used as smart materials for a plethora of advanced environmental applications. The present chapter would be a short overview on any of the most performing nanofibrous materials obtained by electrospinning technology concerning both air filtration and gas/VOCs detection. Can one technology solve the global environmental problems?

The use of nanostructured materials, such as those based on metal or metal oxides, has opened a new way to enhance the performances of chemical sensors making them able to detect gases at ppb level. In this type of sensors, the conductance is modulated by the presence of analytes that interact through physical-chemical processes of absorption and desorption, inducing changes in mobility or carriers density. The nano-scale dimensions of these materials enhance the interaction phenomena in terms of time and responses. In order to activate the physical/chemical interaction processes of the sensors based on oxide materials, an high operating temperature (200-400 °C) is required, resulting in significant power consumption. In this chapter, we report our recent studies on the possibility to exploit the titania photoconduction to develop gas sensor devices working at room temperature. We present the characterization of two different photoconductive Electrospun sensing layers: the first one is composed of titania nanofibres (TiO2 NFs) and the second of TiO2 NFs decorated with Pt nanoparticles (PtNPs) ranging from 5 to 10 nm.

Photocatalytically decorated Au-nanoclusters TiO2 nanofibers for elemental mercury vapor detection A. Macagnano1, E. Zampetti1, A. Bearzotti1, N. Pirrone1, G. Esposito1, F. De Cesare1,2 1. IIA-CNR, Monterorotondo (RM), Italy 2. DIBAF-University of Tuscia, Viterbo, Italy Summary Electrospun nanofibrous nets of titania (anatase) were deposited on intergitated micro-resistors and photocatalytically decorated with gold nanoclusters (AuNCs) upon UV irradiation. The resulting devices appeared to be conductive even at room temperature (Ohmic behavior), and were investigated as potential chemosensors capable of entrapping and detecting elemental mercury vapors in the atmosphere. The strong affinity and specificity of Au for Hg0 conferred to AuNCs a key role in mercury sensing, by inducing a decrease in current upon mercury adsorption. Sensors conductivity appeared not to be dependent on humidity. The resulting chemosensors are expected to be inexpensive, very stable (due to the peculiar structure), and requiring low power, low maintenance and simple equipment to work. Motivation and results Mercury is a well-known neurotoxic and persistent worldwide pollutant. Since 2010 a European project called Global Mercury Observation System (GMOS) has been involved in creating an international network capable of providing accurate measurements of Hg on a global scale (www.gmos.eu). Presently, air monitors are highly sensitive and capable of detecting the global mercury background, but are complex, costly and high-maintenance (requiring more than 40 monitoring sites and skilled operators). In the present study, hybrid nanofibrous electrospun1 layers of TiO2 coating Pt microresistors were suitably designed in order to create nanostructured 3D-frameworks, potentially capable of adsorbing and revealing elemental mercury vapors in the atmosphere. Specifically, titania fibers were decorated with gold nanoclusters (AuNCs) (Fig. 1,a) induced to grow selectively upon photocatalytic reduction of HAuCl4 caused by UV light irradiation2. The morphology and size of gold nanoclusters, as well as the coverage of fibers, depended on UV irradiation exposure (Fig.1,b-c). The sensors showing Ohmic behavior in air at room temperature (Fig. 2) were here investigated. The strong affinity and specificity of Au for Hg0 explain the sensitive responsiveness of AuNCs on the nanofibrous scaffolds to mercury3, highlighted by the current changes of the sensors upon Hg adsorption. In detail, sensors exposed to mercury vapours, pointed out a decrease in current, and the slope of the electrical signals seemed to be dependent on analyte concentration. When sensors were exposed overnight to high concentration of Hg (PV=1.6o10-3 mbar), their resistance changed by 30% (Fig. 3). In order to test the responsiveness of the device to lower Hg concentration, a dynamic permeation tube was set up to dilute the mercury-saturated gas to the concentration range of interest, by using a mass flow controller system (4-Channel-MKS 247). The final Hg0 concentration (measured by Tekran®2537A) was obtained by tuning the oven temperature and the dilution flow. Relative humidity did not affect the electrical parameters of the sensors. Preliminary results showed that the exposure of sensors to 7.5ng/l of Hg resulted in a decrease in current, with a rate of ~109 nA/min (+2V). By modifying Hg concentration, the adsorption rate also changed. Quick thermal shots could restore sensors, due to the high porosity of the layer and the extremely reduced size of the gold nanoclusters.

Titanium oxide nanofibers were successfully prepared via thermal treatment of electrospun composite polymer (PVP)/TiO2 nanofibers. The morphology and crystal structure were characterized by SEM and TEM. It was confirmed that the calcination process was responsible for the removal of PVP component and the growth of crystalline TiO2. The resulting nanofibers, which have a quite rough surface, an average diameter of 60 nm and a length reaching hundreds of μm, were found to be formed by the agglomeration of TiO2 nanoparticles with brookite phase. Gas-sensing tests towards ethanol demonstrated n-type sensing response and good reversibility at an operating temperature of 450 °C. A first tentative to model electrical impedance spectra was made in order to understand charge transport in relationship with morphological and structural aspects.

This work describes the results of a handheld sensor system for monitoring exhaled nitric oxide. The device was developed during a framework of 3-year national project “NOESIS” in cooperation with an Italian SME (Medical International Research S.r.l.). In this apparatus a conductive sensor based on titania nanofibers coated with an ultra-thin film of PEDOT:PSS is capable of detecting up to 5 ppb of NO gas. The sensor system implements a smart recirculation measurement methodology to comply recommendations of the American Thoracic Society and European Respiratory Society about the medical instrumentations devoted to monitor and diagnose the respiratory inflammations. Such implemented system executes the measure in 90 seconds, with an exhalation time of about 10 seconds.

The thermogravimetry technique allows to study desorption and sublimation processes of volatile compounds in different environments. This technique shows a large range of applications for planetary in- situ mission, e.g. the measurement of water and organics in a planetary environment. The capability of a thermogravimeter to study water desorption from clay has been verified. Another experiment which can find application in a planetary mission concerns the measurement of enthalpy of sublimation of a particular volatile compound.

Nanowires are significant potential candidates for the realization of the next generation of sensors since they offer high surface-to-volume-ratios, Debye length comparable to interacting molecules and they can be incorporated into microelectronic devices. Therefore, TiO2 electrospun nanofibers based chemoresistors were successfully designed, manufactured and investigated in order to obtain versatile and highly performing sensors for gas and volatile chemicals. Ease of deposition technique and its cost effective approach, strong adhesion of the fibers on the substrate and stability over time, quick and selective responses to low concentrations of several classes of VOCs, were some of the investigated basic features of the provided sensors.

The Europa-Jupiter System Mission (EJSM) is a joint ESA/NASA mission under study, within which there will be orbital platforms targeted to both Europa (JEO) and Ganymede (JGO) [1]. We describe here a ?Thermogravimetry/biosensor system designed to measure volatile (water/organics) compounds and detect possible biosignatures from Europa and Ganymede surface or subsurface. The instrument is studied in the framework of the Penetrator Surface Elements proposed to EJSM.

In this work we present a process to fabricate low-temperature polysilicon (LTPS) TFTs on polyimide (PI) layers, spin-coated on Si-wafer used as rigid carrier. This process has been then used to fabricate elementary circuits as well as circuits for sensor applications.

Among various attempts of mimicking olfactory system the present work focuses on the sensorial surface of mammalian olfactory cells. The aim of this research is to develop, in a single step, synthetic fibres mimicking the long, no motile cilia of the olfactory cells. Electrospun conductive nanofibrous layers of doped polyaniline, suitably blended to a group of polymers capable to carry the jet, have been easily assembled on chemoresistors (interdigital microelectrodes, IDEs). Such highly sensitive sensors have been able to detect gases in traces of relevant medical significance, mainly because of high density of sorption sites of the sensor. Changing the carriers, the range of sensitivity to gases could be tuned. The key role of the selected carrier polymers (polyethylenoxide of different molecular weights, PEO, polyvinilpyrrolidone, PVP, and polystyrene, PS) to the final sensor features has been highlighted by morphology analysis (texture analysis) and electrical measurements before and after gas interaction.

Usually, ammonium in soil is carried out through steam distillation of ammonia obtained after alkalinization of soil extracts and further back titration of the collected solutions. Alternatively, ion selective electrodes (ISE) specific for ammonium ions can be used, in order to measure their concentration in aqueous soil extracts. The aim of this study is to assess the possibility to use, alternatively to the previous techniques, two kinds of chemical sensors able to measure NH(3), such as an interdigital microelectrode (IDE) coated of conductive polymer and a sensors array, usually named electronic nose (EN), based on quartz crystal microbalances (QCMs) covered with functionalized polymers. These sensors were chosen on the base of their ability to detect NH(3) in sample headspace (specifically or aspecifically, respectively). Therefore, NH(4)(+) in solution was converted to NH(3) by alkalinizing soil extracts. Sensors were calibrated at first against known concentrations of NH(4)(+). Results were compared with those obtained with an ISE for NH(4)(+).

Polyaniline (PANi) is one of the most noteworthy conductive polymers because of the low cost of its synthesis, its conductive features when doped, and its thermal and environmental stability. This conducting polymer shows chemical selectivity, which allows it acting as excellent material for the immobilization of gas molecules, exhibiting highly reversible redox behaviour. Its sensing performances are well known in literature most of all for ammonia detection. Usually, higher potentialities of sensing materials can be realized making use of nanostructured elements. Electrospinning technique is a successful and easy method to assemble nano-structures (nanowires, nanobeads, nanotubes), as occurs in natural systems (biomimetic approach), in a single step, on appropriate transducers.

The electronics has been the real driving force of nanotechnology for its applicability in the field of devices miniaturization. In this area, the challenge is to go even further down with the dimensions trying to understand the physical-chemical mechanisms that affect the realization of nanostructures with the objective of producing smaller devices, more powerful and requiring less energy to operate.

The interest on metal nanoparticles and in particular on gold nanoparticles (AuNPs) has risen exponentially in the past decade, due to the unique properties of gold in nanostructured dimensions. The use of these products as chemical interactive materials (CIM) on resistive type and quartz microbalance (QMB) sensors has been recently developed. Composites of AuNPs with phenylacetylene copolymers have been produced and tested for sensing purposes. Humidity and alcohols sensors based on composites AuNPs/copoly(phenylacetylene/allyl mercaptan) AuNPs/P(PA/AM) and AuNPs/ copoly(phenylacetylene/phenylacetylthiolate) AuNPs/P(PA/PAS) have been studied using resistive type and QMB devices.

The interaction of two different phenomena, the gas diffusion in a membrane and the spatial dependent sensitivity of a transducer, affects the final response of a sensor. In this paper we present data and simulation of a quartz crystal microbalance (QCM) utilizing a thin film of palladium as hydrogen detector. Preliminary results show that it is possible to exploit these peculiar properties of the membrane and of the transducer to enhance the overall performance of the sensor. The membrane and transducer used for this work are merely one example and the concept here exposed can be applied to other more complex systems.

Thermo gravimetric analysis (TGA) is a widely used technique to investigate condensation/sublimation and absorption/desorption processes of volatile compounds in different environments. TGA analyzers are used to investigate outgassing contamination in Space, dehydration and organic decomposition in minerals, as well as to measure moisture content in foods or develop temperature profiles for firing ceramics [1,2,3]. TGA is often coupled with other analytical techniques (e.g., mass spectroscopy and FTIR) in order to determine the specific off-gas materials [4,5].

Il contributo verte sui rapporti tra giudicato amministrativo di legittimità e riesercizio del potere amministrativo, con specifico riguardo alle controversie relative a interessi legittimi pretensivi. Dopo alcune preliminari considerazioni sul rapporto tra cognizione ed esecuzione nel processo amministrativo di legittimità, sull’ambito oggettivo del giudicato amministrativo in relazione alla situazione giuridica soggettiva dedotta nonché, in termini più generali, sui principi di effettività e di pienezza della tutela giurisdizionale, lo studio evidenzia come un ampliamento della cognizione del giudice dell'ottemperanza possa attuarsi attraverso una nozione evoluta di elusione del giudicato, che tenga conto dell'esigenza di attuare il giudicato amministrativo secondo buona fede, nonchè per effetto della acquisita qualificazione del commissario ad acta quale ausiliario del giudice. Nel trattare di tali aspetti, si evidenzia inoltre che se il concetto tradizionale di giudicato a formazione progressiva può ritenersi superato nel c.p.a. con riguardo al carattere implicito della regola traibile dal giudicato per effetto della esplicitazione del contenuto ordinatorio già al termine del giudizio di cognizione, tanto non può affermarsi relativamente al carattere della incompletezza della regola, il quale permane a fronte della peculiare applicazione del principio per cui il giudicato copre il dedotto e il deducibile nel giudizio amministrativo di sola legittimità.