New Techniques for the Measurement of Second and Third Generation Photovoltaics

New generations of photovoltaics (PV) have demonstrated a significant cost-reduction with respect to c-Si wafer-based modules. Though second (thin-film) and third generation PV (high-intensity, low-cost) are already in the PV market, the preparation of standard procedures for their characterization is still ongoing. This work was developed by the author in order to extend some of the existing characterization techniques to a set of three different emerging technologies: multi-junction thin-film modules, concentrator PV cells and luminescent solar concentrators. An original method for the spectral response measurement of large area thin-film multijunction modules is presented in the first part: the method is validated with several examples. A basic theoretical approach is also presented to propose innovative explanations of measurement artefacts that are observed in the literature. In the second part of the thesis, the setup, characterization and classification of a high intensity pulsed solar simulator for concentrator PV cells is illustrated. A new procedure for the preparation of a set of filtered reference cells for the irradiance detection at high intensities is also presented, providing an original tool for the verification of the linearity of these devices towards irradiance, which is usually assumed in the literature. In the third part the performance characterization of high-efficiency luminescent solar concentrators is presented: a simple ray-tracing model and its experimental validation, the impact of backside diffusive reflector on the performance of this kind of devices are mainly highlighted. The work was developed in support of the activities of the European Solar Test Installation laboratory of the European Commission, a centre of reference for PV testing

3D Reconstruction with Low Resolution, Small Baseline and High Radial Distortion Stereo Images

In this paper we analyze and compare approaches for 3D reconstruction from low-resolution (250x250), high radial distortion stereo images, which are acquired with small baseline (approximately 1mm). These images are acquired with the system NanEye Stereo manufactured by CMOSIS/AWAIBA. These stereo cameras have also small apertures, which means that high levels of illumination are required. The goal was to develop an approach yielding accurate reconstructions, with a low computational cost, i.e., avoiding non-linear numerical optimization algorithms. In particular we focused on the analysis and comparison of radial distortion models. To perform the analysis and comparison, we defined a baseline method based on available software and methods, such as the Bouguet toolbox [2] or the Computer Vision Toolbox from Matlab. The approaches tested were based on the use of the polynomial model of radial distortion, and on the application of the division model. The issue of the center of distortion was also addressed within the framework of the application of the division model. We concluded that the division model with a single radial distortion parameter has limitations

Effectiveness of omalizumab in a patient with severe asthma and atopic dermatitis

The anti-IgE antibody omalizumab is currently indicated in severe asthma not controlled by standard drug therapy. Recently, new indications for omalizumab were suggested, which include atopic dermatitis (AD), a skin disorder characterized by elevated levels of IgE. We report the case of a 39-year old woman with severe asthma and severe AD, both resistant to conventional drug treatment. The patient had a IgE level of 1304 kU/L, which exceeded the recommended maximum level for treating asthma with omalizumab (stated in 700 Ku/L) but was far lower than previously reported in cases of AD treated with anti-IgE. The treatment consisted of a dose of omalizumab 375 mg every two weeks, and induced a rapid improvement of asthma, with no need of other drugs after three months, along with a progressive decline of severity of AD, which after five months was completely cured. These findings suggest the usefulness of omalizumab in patients with concomitant severe asthma and AD, also considering the pharmaco-economic balance obtained by withdrawing the multiple drugs used to treat both diseases

Second international spectroradiometer intercomparison: results and impact on PV device calibration

This paper describes the results of an intercomparison of spectroradiometers for measuring global normal incidence and direct normal incidence spectral irradiance in the visible and in the near infrared, together with an assessment of the impact these results may have on the calibration of the short circuit current (I-sc) of triple-junction photovoltaic devices and on the relevant spectral mismatch calculation. The intercomparison was conducted by six European scientific laboratories and a Japanese industrial partner. Seven spectroradiometer systems, for a total of 13 different instruments/channels using two different technologies and made by four different manufacturers were involved. This group of systems represents a good cross section of the instrumentation for solar spectrum measurements available to date. The instruments were calibrated by each partner prior to the intercomparison following their usual procedure and traceability route in order to verify the entire measurement and traceability chain. The difference in measured spectral irradiance showed to have an impact on the calibration of a set of Iso-Type cells varying from +/- 2% to +/- 14% for middle and bottom cell, respectively

Second international spectroradiometer intercomparison: preliminary results and impact on PV device calibration

This paper describes the preliminary results of an intercomparison of spectroradiometers for global (GNI) and direct normal incidence (DNI) irradiance in the visible (VIS) and near infrared (NIR) spectral regions together with an assessment of the impact these results may have on the calibration of triple-junction photovoltaic devices and on the relevant spectral mismatch calculation. The intercomparison was conducted by six European scientific laboratories and a Japanese industrial partner. Seven institutions and seven spectroradiometer systems, representing different technologies and manufacturers were involved, representing a good cross section of the todays available instrumentation for solar spectrum measurements

In vitro effects of different levels of quebracho and chestnut tannins on rumen methane production, fermentation parameters, and microbiota

Both condensed and hydrolysable tannins (CTs and HTs, respectively) have the ability to reduce enteric CH4 production in ruminants. However, the precise mechanism of action is not fully understood. Among the proposed hypotheses are the reduction of ruminal digestibility, direct control action on protozoa, reduction of archaea, and a hydrogen sink mechanism. In this in vitro study, which simulated rumen fermentation, two additives, one containing CTs (70% based on DM) from quebracho and one with HTs (75% based on DM) from chestnut, at four levels of inclusion (2, 4, 6, 8% on an as-fed basis) were added to the fermentation substrate and tested against a negative control. Both types of tannins significantly reduced total gas (GP) and CH4 (ml/g DM) production during the 48 h of incubation. The lower GP and CH4 production levels were linked to the reduction in dry matter digestibility caused by CTs and HTs. Conversely, no significant differences were observed for the protozoan and archaeal populations, suggesting a low direct effect of tannins on these rumen microorganisms in vitro. However, both types of tannins had negative correlations for the families Bacteroidales_BS11 and F082 and positive correlations for the genera Prevotella and Succinivibrio. Regarding the fermentation parameters, no differences were observed for pH and total volatile fatty acid production, while both CTs and HTs linearly reduced the NH3 content. CTs from quebracho were more effective in reducing CH4 production than HTs from chestnut. However, for both types of tannins, the reduction in CH4 production was always associated with a lower digestibility without any changes in archaea or protozoa. Due to the high variability of tannins, further studies investigating the chemical structure of the compounds and their mechanisms of action are needed to understand the different results reported in the literature

Guidelines for the use and interpretation of diagnostic methods in adult food allergy

Food allergy has an increasing prevalence in the general population and in Italy concerns 8 % of people with allergies. The spectrum of its clinical manifestations ranges from mild symptoms up to potentially fatal anaphylactic shock. A number of patients can be diagnosed easily by the use of first- and second-level procedures (history, skin tests and allergen specific IgE). Patients with complex presentation, such as multiple sensitizations and pollen-food syndromes, frequently require a third-level approach including molecular diagnostics, which enables the design of a component-resolved sensitization profile for each patient. The use of such techniques involves specialists' and experts' skills on the issue to appropriately meet the diagnostic and therapeutic needs of patients. Particularly, educational programs for allergists on the use and interpretation of molecular diagnostics are needed

A survey of clinical features of allergic rhinitis in adults

Background: Allergic rhinitis (AR) has high prevalence and substantial socio-economic burden. Material/Methods: The study included 35 Italian Centers recruiting an overall number of 3383 adult patients with rhinitis (48% males, 52% females, mean age 29.1, range 18\u201345 years). For each patient, the attending physician had to fill in a standardized questionnaire, covering, in particular, some issues such as the ARIA classification of allergic rhinitis (AR), the results of skin prick test (SPT), the kind of treatment, the response to treatment, and the satisfaction with treatment. Results: Out of the 3383 patients with rhinitis, 2788 (82.4%) had AR: 311 (11.5%) had a mild intermittent, 229 (8.8%) a mild persistent, 636 (23.5%) a moderate-severe intermittent, and 1518 (56.1%) a moderate-severe persistent form. The most frequently used drugs were oral antihistamines (77.1%) and topical corticosteroids (60.8%). The response to treatment was judged as excellent in 12.2%, good in 41.3%, fair in 31.2%, poor in 14.5%, and very bad in 0.8% of subjects. The rate of treatment dissatisfaction was significantly higher in patients with moderate-to-severe AR than in patients with mild AR (p<0.0001). Indication to allergen immunotherapy (AIT) was significantly more frequent (p<0.01) in patients with severe AR than with mild AR. . Conclusions: These fndings confirm the appropriateness of ARIA guidelines in classifying the AR patients and the association of severe symptoms with unsuccessful drug treatment. The optimal targeting of patients to be treated with AIT needs to be reassessed