Innovative Output, Infra-Industry Spilloves, and R&D Cooperation: Theory and Evidence.

We analyse both the theoretical and empirical side of the issue of R&D spillover. Each firm`s R&D costs are increasing in the amount of the information transmitted to the other firms , and we account for the possibility that the firms control spillovers. We consider both Cournot-Nash and Cornot-Stackelberg behavior. The empirical analyst suggests that (i) firms` control on spillovers is relatively low; (ii) the cost-saving effect associated to joint ventures or R&D cartels is confermed for industries where firms rely mainly upon own R&D as a source of innovation; (iii) R&D cooperation may increase informationsharing, thereby enhancing spillovers

Organic Semiconductors-Based Devices Electrical Reliability to Environmental Stress

In this thesis, I report on the characterisation of the response of organic semiconductor based devices, namely organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs) and organic photovoltaic diodes (OPVDs) to environmental stress factors such as electrostatic discharge (ESD) and neutrons irradiation. The ESD stress was obtained by means of a transmission line-pulsing (TLP), responsible to generate current pulses with an increasing amplitude and a duration of few tens of nanoseconds. The exposure to neutron irradiation was obtained in the pulsed neutron and muon source at ISIS part of the Rutherford Appleton Laboratories (RAL). The tested devices were: P3HT (poly(3-hexylthiophene)):PCBM ([6,6]- phenyl C61 butyric acid methyl ester) bulk heterojunction solar cells; PBTTT (poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2- b]thiophene) and P3HT OFETs; F8BT (poly(9,9'-dioctylfluorene-alt-benzothiadiazole)) OLEDs. An analysis of both electrical (IV and JV curves, Electroluminescence (EL)) and optical (photoluminescence (PL), Raman Spectroscopy) characteristics of tested devices prior and following the exposure to various degrees of ESD, neutron irradiation or both is reported. For each tested device I obtained the respective TLP parameters (the leakage current (ILEAK), the TLP current (ITLP), the TLP voltage (VTLP), the TLP resistance (RTLP)) and the correlation of these with parameters extracted by means of their electrical/optical characterisation, namely: (i) the charge mobility, the threshold voltage (VTH) and the on/off ratio of OFETs; (ii) the current density (Jsc), the open-circuit voltage (Voc), the fill factor (FF) and the power conversion efficiency (η) of OPVs; (iii) the turn-on voltage (Von), the external quantum efficiency (EQE) and the EL maximum wavelength emission (λmax) of OLEDs. Importantly, the activity carried out in this thesis gives novel insights about the response of conjugated polymer-based devices with respect to the stressing stimuli (ESD events, cosmic rays) they are exposed to in their most suitable application fields (space, medicine, robotics), such as the energy necessary to cause a total or partial failure during ESD events, the requirements necessary to design electrical protections, the expected loss of device figures after a decade of exposure to cosmic rays. Interestingly, the results in this thesis reported point out, in most of the cases, an excellent robustness of these devices to both ESD and cosmic rays stress. In fact, whilst technology silicon-based is found to suffer a permanent failure in most of the cases for an applied TLP power lower than 400 W, polymer-based technology was found to withstand up to 800 W (OPVs and OLEDs) without suffering permanent damages. As regards the stress correlated to the same dose of neutrons irradiation, optoelectronic devices based on inorganic semiconductors suffer of a 90% reduction of their figures of merit (JSC, h), whilst the same figures are reduced of only 20% in polymer-based devices. Although previous works are reported in literature, the work reported in this thesis, at the best of my knowledge, is the first work reporting a systematic quantitative TLP characterisation of organic devices along with a qualitative description of the effects on the organic materials within these devices because of the conditions imposed by the TLP test (high-frequency, high-voltage). Therefore, this thesis opens a new scenario proposing an investigating tool aimed both at measuring parameters useful for the design of the devices and at highlighting organic materials properties that can lead organic electronics to gain its definitive momentum

Construction of a Scanning Thermal Atomic Microscope (SThM) for nanopatterning of advanced functional materials

The aim of this thesis is to design a Scanning Thermal Force Microscope (SThM). This machine manufactures nano devices made with polymers utilizing a thermal process. The process consists of heating up a thermal scanning probe by controlling the current flowing in it. The first chapter of this thesis describes in general terms what an Atomic Force Microscope (AFM) is and what its functions are. Afterwards there is an explanation of how an AFM can be developed in order to be used as an SThM. The second chapter focuses on the features of the system we developed. In this section, the description of the system is divided into four parts : the optics, the signal processing, the piezo controller and the thermal control. In each of these parts, there is a brief description of its main features and the design choices we made. The third chapter describes the optics of the system we developed following Binnig, Quate and Gerber’s 1986 design of the AFM. This section also contains the results we obtained testing different lasers and the problems we had with the calibration of the system due to the thermal scanning probe used. The fourth chapter deals with the signal processing of the system. Firstly, there is an analysis of the noise that affects the system. The value of the signal-noise ratio is obtained from experimental data gathered doing scans of a step with a height of 30 nm. Afterwards there is a description of the development of a filter we made in order to reduce the noise affecting the system. The fifth chapter describes the development of the thermal control of the system. The control of the temperature is obtained through a Wheatstone bridge and a proportional-integral-differential (PID) control. We developed the system using a digital signal processor (DSP), a nano position controller, a 3A class red laser and a Butterworth low-pass filter which we designed and tested. We decided to design the filter using Orcad and Multisim CAD programmes. The results obtained were processed through Matlab scripts. The control of the system requires the programming of the DSP which we programmed using AdWin language. The main results achieved are : succeeding in scanning devices with a height of 30 nm and controlling the temperature of the system up to 220°Celsius. This project has been developed in the Physics and Astronomy Department of University College London and is the property of Prof. Franco Cacialli and his group

Methane-Assisted Iron Oxides Chemical Looping in a Solar Concentrator: A Real Case Study

Recent interest in hydrogen as an alternative fuel for lowering carbon emissions is funding the exploration of new ways to cleanly produce this molecule. Iron oxides can be used within a process of chemical looping. More specifically, they can lose oxygens at extremely high temperature in an inert atmosphere. An alumina receiver could not stand the extreme thermal stress, while steel (AISI 316 and Inconel Hastelloy c-276) lasted enough for the reaction to start, even if at the end of the process the receiver melted. Operating at a temperature above 1000 K helped the reaction switch from methane chemical looping combustion to chemical looping reforming, thus favouring H2 and CO yields. The gas flow outlet from the reactor reached a percentage up to 45% of H2 and 10% of CO. Carbon dioxide instead reached very low concentrations. While CO and CO2 reached a peak at the beginning of the experiment and then decreased, H2 was oscillating around a stable value. Unreacted methane was detected. The temperatures recorded in the reactor and the gas mixture obtained were used to validate a multiphysical model. The heat transfer and the chemistry of the experiment were simulated

Environmental factors influence the rate of human herpesvirus type 8 infection in a population with high incidence of classic Kaposi sarcoma

High prevalence of human herpesvirus type 8 (HHV-8) infection has been reported on the island of Sardinia. Among emigrants from Sardinia, rates of HHV-8 infection are lower than they are in Sardinia and are similar to those observed in the local population. Thus, environmental factors seem to play a relevant role in affecting the prevalence of HHV-8 infection

Clinical validation of 13-Gene DNA methylation analysis from oral brushing: a non invasive sampling procedure for early detection of oral squamous cell carcinoma. A multicentric study

1. Introduction In a recent study our research group described a non-invasive sampling procedure based on DNA methylation analysis of a set of 13 genes with a high level of accuracy (sensitivity 96.6%, specificity 100%) in the detection of squamous cell carcinoma of the oral cavity (OSCC) [1]. The purpose of the present study was to test the diagnostic performance of this non invasive sampling procedure in an italian multicentric study. 2. Materials and Methods Oral brushing specimens were collected in ten different italian units of oral medicine. Each oral medicine unit collected blindly 10 brushing specimens from patients affected by OSCC and an equal number of age and sex-matched healthy controls. 13-gene DNA methylation analysis was performed and each sample was considered positive or negative in relation to a predefined cut-off value. 3. Results 181 out of 200 planned specimens were analyzed. DNA could not be amplified in 4 cases (2.2%). 86/93 (92.5%) specimens derived from OSCC patients were detected as positive and 70/84 (83.3%) specimens derived from healthy donors showed a negative score. 4. Conclusions Data from multicentric study confirmed a high level of sensitivity of our procedure whereas level of specificity is slightly lower if compared to our previous study. These data suggest that our procedure may be proposed as a first level diagnostic test with the aim to avoid a diagnostic delay in Oral Squamous Cell Carcinoma. Conflicts of Interest: As a possible conflict of interest, L. Morandi and D.B.G. submitted a patent (the applicant is the University of Bologna) in November 2016 to the National Institute of 398 Industrial Property; however, we believe that this is a natural step of translational research (bench-to-bedside) 399 and guarantee that the scientific results are true. The remaining authors declare that they have no competing 400 interest

A New Method for the Experimental Assessment of Finger Haemodynamic Effects Induced by a Hydraulic Breaker in Operative Conditions

Abstract: A New Method for the Experimental Assessment of Finger Haemodynamic Effects Induced by a Hydraulic Breaker in Operative Conditions: Matteo VALENTINO, et al