Realization and dissemination of high frequency power standard at INRIM

In the High Frequency (HF) field, the primary power standard is maintained through reference sensors calibrated in terms of effective efficiency η_e. These devices are in turn used to transfer the power standard by means of direct comparison on the same matched generator. For this kind of operation, the only knowledge of the effective efficiency of the device is not enough and additional parameters of the reference sensor are necessary.The paper describes the methods and techniques used at INRIM to disseminate the “HF power standard”, with emphasis to all the technical aspects involved, in order to provide a thorough explanation of the procedures implemented.     

Interpreting sensory data by combining principal component analysis and analysis of variance

This paper compares two different methods for combining PCA and ANOVA for sensory profiling data. One of the methods is based on first using PCA on raw data and then relating dominating principal components to the design variables. The other method is based on first estimating ANOVA effects and then using PCA to analyse the different effect matrices. The properties of the methods are discussed and they are compared on a data set based on sensory analysis of a candy product. Some new plots are also proposed for improved interpretation of results.     

Sequential modeling of a low noise amplifier with neural networks and active learning

The use of global surrogate models has become commonplace as a cost effective alternative for performing complex high fidelity computer simulations. Due to their compact formulation and negligible evaluation time, global surrogate models are very useful tools for exploring the design space, what-if analysis, optimization, prototyping, visualization, and sensitivity analysis. Neural networks have been proven particularly useful in this respect due to their ability to model high dimensional, non-linear responses accurately. In this article, we present the results of an extensive study on the performance of neural networks as compared to other modeling techniques in the context of active learning. We investigate the scalability and accuracy in function of the number design variables and number of datapoints. The case study under consideration is a high dimensional, parametrized low noise amplifier RF circuit block.     

Variation in forage quality and chemical composition among Italian accessions of Bituminaria bituminosa (L.) Stirt.

Native Bituminaria bituminosa (L.) Stirt. accessions from central and southern Italy were evaluated for chemical composition to assess their nutritional value as forages. The germplasm was evaluated subjectively ex situ for intensity of ‘oil’ smell and analysed for fibre fraction, crude protein and water‐soluble carbohydrate contents as well as furanocoumarin (psoralen and angelicin) concentration. Total phenolics and their antioxidant activity were also evaluated. The quality parameters indicated this species as a good forage source, showing nutritive values similar to those of other wild legume species. Psoralen and angelicin contents ranged from 2.8 to 5.4 and from 2.3 to 4.7 mg g^?1 dry weight respectively, while total phenolic concentrations were between 11.2 and 13.5 mg g^?1 dry weight. Correlations among forage quality parameters, chemical components and climatic features at sites of origin were also assessed. Copyright © 2007 Society of Chemical Industry     

Influence of Active Packaging on the Shelf‐life­ of Minimally Processed Fish Products in a Modified Atmosphere

The effectiveness of an innovative foam plastic tray, provided with absorbers for volatile amines and liquids, on the shelf‐life of different fish products packed under a modified atmosphere (40%CO₂:60%N₂), was evaluated in comparison with a standard tray. Fillets of sole (Solea solea), steaks of cod (Merluccius merluccius) and whole cuttlefish (Sepia fillouxi), placed in the two different kinds of trays, were kept at 3°C. Microbiological (TBC‐, Gram‐negative‐, H₂S‐producing bacteria and lactic acid bacteria) and chemical (surface pH, TMA headspace) analyses were carried out after 3, 7 and 10 days of storage. The new packaging, associated with a rigorous control of storage temperature, increased the shelf‐life up to 10 days. In fact, the innovative tray sequestrated the greater part of trimethylamine from the headspace and led to delayed microbial growth, especially of Gram‐negative and H₂S‐producing bacteria, and in addition it favoured the growth of bacterial strains such as Moraxella phenylpiruvica , which are not involved in off‐flavouring production (especially H₂S), because of their lypolitic activity. Copyright © 2001 John Wiley & Sons, Ltd.     

A framework for the deployment of adaptable web service compositions

The basic paradigm of service-oriented architectures—publication, discovery, and use—can be interpreted in different ways. Current technologies assume a static and rigid approach: UDDI was conceived with the idea of a centralized repository for service publication and BPEL only supports design–time bindings between the orchestrated workflow and the external services. The trend, however, is towards more flexibility and dynamism. The single centralized repository is being substituted by dedicated repositories that cooperate and exchange information about stored services on demand. Design–time compositions are complemented by mechanisms to allow for the selection and binding of services at runtime. This paper presents the research results of our group in delivering a framework for the deployment of adaptable Web service compositions. The publication infrastructure integrates existing heterogeneous repositories and makes them cooperate for service discovery. The deployment infrastructure supports BPEL-like compositions that can select services dynamically, and also adjust their behavior in response to detected changes and unforeseen events. The framework also provides a monitoring-based validation of running compositions: we provide suitable probes to oversee the execution of deployed compositions. The various parts of the framework are exemplified on a common case study taken from the automotive domain. This research is partially supported by the European IST project SeCSE (Service Centric System Engineering) and the Italian FIRB project ARTDECO (Adaptive infRasTructures for DECentralized Organizations).     

Transformation of ethanol into hydrocarbons on ZSM-5 zeolites modified with iron in different ways

ZSM-5 zeolites modified by iron incorporation through post-synthesis ion exchange and those synthesized with iron addition to the synthesis medium were compared in the reaction of liquid hydrocarbons production from ethanol. AA, TPR, FTIR, XRD, SEM, nitrogen adsorption and photoacoustic spectroscopy were used for the samples characterization. Acid leaching and ammonium exchange were tested for obtaining the acid form of the zeolite, with similar results, the major difference being a faster deactivation in the latter case. The best yield of liquid hydrocarbons was obtained with the samples with low iron content. The product distribution in both gaseous and liquid phases was independent of the way the zeolite was obtained or the iron was introduced, with major variations only with time (due to deactivation).     

Synthesis,characterization and antibacterial activity studies of poly-{styrene-acrylic acid} with silver nanoparticles

This work reports the preparation and characterization of copolymer poly-{styrene-acrylic acid} with monomeric ratio of styrene/acrylic acid of 9:1 using benzoyl peroxide as initiator and furthermore filled with nanosilver (25 ppm and 50 ppm) in water/acetone (1:40 v/v). The nanosilver emulsion was obtained from chemical reduction using NaBH₄ as reducing agent and sodium citrate as the stabilizer. The preparation of nanosilver emulsion was monitored by the appearance of a Plasmon Resonant Absorption band in a UV–visible spectrophotometer and the particles sizes were observed through TEM. Microbiological studies were performed to investigate the antimicrobial activity of this new material against the microorganisms Escherichia coli (ATCC-25922) and Staphylococcus aureus (ATCC-6538), used as reference strains. The antimicrobial activity of the poly-{styrene-acrylic acid} filled with nanosilver was confirmed by the presence of an inhibition halo of the bacterial growth in seeded culture media, but was not found with the poly(styrene-acrylic acid) alone. The present work suggests that silver ions are released from the polymeric matrix to the culture media and have the ability to tune the Ag⁺ ions released by controlling the amount of Ag nanoparticles embedded in the composite.