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• Isotropic hardening models over-predict residual stresses for high applied pressures. • Unbounded residual stress increase is predicted by conventional isotropic models. • The effect of cyclic plasticity modelling increases if multiple pulses are applied. • Cyclic plasticity modelling is essential in extended surface high coverage treatments. Laser shock processing (LSP) is a mechanical surface treatment to induce a compressive residual stress state into the near surface region of a metallic component. The effect of the cyclic deformation properties of ductile materials on the final residual stress fields obtained by LSP is analysed. Conventional modelling approaches either use simple tensile yield criteria, or isotropic hardening models if cyclic straining response is considered for the material during the peen processing. In LSP, the material is likely to be subject to cyclic loading because of reverse yielding after the initial plastic deformation. The combination of experiment and modelling shows that the incorporation of experimentally-determined cyclic stress-strain data, including mechanical hysteresis, into material deformation models is required to correctly reflect the cyclic deformation processes during LSP treatment and obtain accurate predictions of the induced residual stresses. [ABSTRACT FROM AUTHOR]

Abstract: Wind power is one of the fastest-growing technologies for renewable energy generation. Unfortunately, in the recent years some cases of degradation on certain telecommunication systems have arisen due to the presence of wind farms, and expensive and technically complex corrective measurements have been needed. This paper presents a comprehensive review on the impact of wind turbines on the telecommunication services. The paper describes the potential affections to several telecommunication services, the methodology to evaluate this impact, and mitigation measures to be taken in case of potential degradation, both preventive and corrective. The telecommunication services included in this review are those that have demonstrated to be more sensitive to nearby wind turbines: weather, air traffic control and marine radars, radio navigation systems, terrestrial television and fixed radio links. The methods described in the paper allow a thorough case-by-case analysis before the wind farm is installed, taking into account the particular features of each installation and the involved services. The prediction of the potential impact makes it possible to propose alternative solutions in order to assure the coexistence between the wind turbines and the telecommunication services. [Copyright &y& Elsevier]

Abstract: Recent studies on the use of vegetable fibers in polymers have led to the conclusion that the fibers must be treated to improve their adherence to plastic matrices. The present study investigated the effect of physical and chemical treatments on the suitability of fiber from the Canary banana tree for use as reinforcement for polymers in injection molding processes. This fiber has the advantage of being derived from the vegetable waste that is produced by farms involved in banana cultivation in the Canary Islands. Sodium hydroxide and maleic anhydride were used to treat the fiber under different conditions of pressure and temperature, and then the fiber was examined by thermogravimetric analysis and Fourier transform infrared spectroscopy. The best treatment for improving the thermal properties of banana fiber, with no significant decrease in mechanical behavior, for use in a composite was a combination of 1N NaOH and saturation pressure. [Copyright &y& Elsevier]

Abstract: Nanomaterials have been demonstrated to possess novel characteristics that can be applied in developing new packaging with better properties than packaging produced with micromaterials. Such developments include the production of packaging with improved barrier properties, which applied to the food industry will extend the shelf life of a food, thereby expanding its marketing potential. The present study entailed the optimization of experimental variables (pressure, temperature, processing time, feed position, etc.) involved in the elaboration of polypropylene and polyethylene films with nanoparticles, to obtain a film with good exfoliation, barrier and mechanical properties. SEM, TEM and XRD were also evaluated as tools for determining the degree of exfoliation of nanoparticles. Optimization of the technology involved in production of an exfoliated nanocompound is a complex process in which multiple variables and parameters are involved. The results of the study showed that the feed position of the nanoparticle in the double screw extruder is of vital importance in obtaining an exfoliated film. The maximum temperatures used in the extruder were 170°C and 130°C, for polypropylene and polyethylene respectively. [Copyright &y& Elsevier]

Abstract: Bone marrow (BM) cells fractioned in Percoll gradients yield a low-density fraction (Fr3) highly enriched in suppressor activity. Previously, it has been demonstrated that BM associated suppressor activity was mediated by early myeloid cells, through a mechanism dependent on endogenous IFNγ and nitric oxide production after bacterial stimuli, e.g. lipopolysaccharide (LPS). However, the mechanism(s) through which the IFNγ is produced in BM has not yet been fully elucidated. Therefore, in the present study we investigated the involvement of IL-12, IL-18 and IFNβ on the production of IFNγ and nitric oxide in cultures of BM Fr3 cells, and characterized the IFNγ-producing cells, in response to LPS. The results show that both IL-12 and IFNβ, but not IL-18, are involved on IFNγ production. However, only IFNβ appears to be critical on nitric oxide production. Furthermore, we found that cells of the Thy1.2+CD3+ phenotype produce IFNγ and are tightly involved on nitric oxide production by BM Fr3 cells. In conclusion, IFNβ appears to be critical on IFNγ- and nitric oxide production by BM cells in response to LPS, through a mechanism that is dependent on Thy1.2+CD3+ IFNγ-producing cells. [Copyright &y& Elsevier]

Highlights • Field measurements of non-intentional emissions from generation devices. • Evaluation in the frequency range for Smart Grid communications up to 500 kHz. • Analysis in time and frequency domain of the non-intentional emissions. • Potential impact of the emissions on transmission technologies for Smart Metering. Abstract Narrow Band Power Line Communications (NB-PLC) systems are currently used for smart metering and power quality monitoring as a part of the Smart Grid (SG) concept. However, non-intentional emissions generated by the devices connected to the grid may sometimes disturb the communications and isolate metering equipment. Though some research works have been recently developed to characterize these emissions, most of them have been limited to frequencies below 150 kHz and they are mainly focused on in-house electronic appliances and lightning devices. As NB-PLC can also be allocated in higher frequencies up to 500 kHz, there is still a lack of analysis in this frequency range, especially for emissions from Distributed Energy Resources (DERs). The identification and characterization of the emissions is essential to develop solutions that avoid a negative impact on the proper performance of NB-PLC. In this work, the non-intentional emissions of different types of DERs composing a representative microgrid have been measured in the 35–500 kHz frequency range and analyzed both in time and frequency domains. Different working conditions and coupling and commutation procedures to mains are considered in the analysis. Results are then compared to the limits recommended by regulatory bodies for spurious emissions from communication systems in this frequency band, as no specific limits for DERs have been established. Field measurements show clear differences in the characteristics of non-intentional emissions for different devices, working conditions and coupling procedures and for frequencies below and above 150 kHz. Results of this study demonstrate that a further characterization of the potential emissions from the different types of DERs connected to the grid is required in order to guarantee current and future applications based on NB-PLC. [ABSTRACT FROM AUTHOR]

Abstract: Natamycin is an antibiotic belonging to the group of polyene macrolides extensively employed as additive to prevent the microbial deterioration in food. The Annex III of the Directive 95/2/EC fixes in 1 mg/dm2 the maximum level of the antifungal allowed in the final product. Reliable and sensitive methods for the analysis of natamycin are required to guarantee compliance with food legislation as well as to improve consumer protection. In the present paper, a simple and rapid high performance liquid chromatographic method with diode-array detection (HPLC-DAD) to determine natamycin in food samples was developed. Natamycin was extracted from food samples by using methanol acidified with acetic acid. The chromatographic separation was performed on a reversed-phase Kromasil ODS (C18) (150 × 3.20 mm i.d., 5 μm particle size) and the analysis was completed within 6 min. The method was validated in terms of linearity, limits of detection and quantification, repeatability and recovery. Satisfactory repeatability (R.S.D. (n = 10) < 4%, excellent sensitivity (LOD: 0.01 μg/mL; LOQ: 0.05 μg/mL) and appropriate recoveries were achieved. With the proposed method natamycin levels were determined in different food items. Data showed that two samples exceeded the limit established by the Annex III of the Directive 95/2/EC. Natamycin was also detected in samples in which its use is not allowed. The results were confirmed by LC-MS/MS using electrospray ionization (ESI) in positive mode. [Copyright &y& Elsevier]

Abstract: Molecular alloys, that combine a relatively high heat of melting with a suitable melting temperature adapted to the application temperature, are excellent materials for thermal protection and for thermal energy storage. Of special interest is the fact that, by making alloys of molecular materials; the range of melting can be adjusted over a range of temperatures. The present paper reports on the design of MAPCMs to be used for energy storage and thermal protection at temperatures from 70 to 85°C. The aim is to use these materials for thermal protection in the catering sector in order to avoid proliferation of micro organisms; the minimal temperature required is higher than 65°C. The work illustrates how some fundamental studies are helpful in choosing the right composition that is able to work at the temperature required for an application. Several molecular alloys using the n-alkanes are elaborated and characterized. The preparation of mixed crystals, their crystallographic and thermodynamic properties and stability, phase change behaviour, and their use in practical applications are reported. [Copyright &y& Elsevier]

An inverse approach for the Laser Surface Hardening Process is proposed. It departs from specific austenization requirements in terms of a desired size for the austenized region at any cross section of the treated sample, aiming at calculating suitable process parameters to obtain it. This approach contrasts with conventional direct procedures, from process parameters to thermal cycles and austenite distribution, where stochastic design strategies, falling on the dynamics of successive approximations, are performed. A thermo-metallurgical numerical model is used to determine the irradiance distribution capable of meeting the prescribed austenization requirements. This theoretical irradiance distribution is implemented by means of an adaptative high-frequency scanning of the treated surface. The minimum scanning frequency to guarantee the equivalence between the pursued theoretical irradiance distribution and the scanning is established attending to the evolution of temperature and its influence on the austenization rate by means of Avrami Law. A value of 100 Hz grants a continuous heating of the material. Considering this threshold, equations to calculate the parameters of the scanning to achieve the desired irradiance distribution are built. These equations are used to approach a design case where real hardened cross sections are achieved, confirming the utility of the proposed systematic methodology. Unlabelled Image • An inverse approach, from austenization requirements to process parameters specification, is proposed for Laser Hardening. • A thermo-metallurgical model provides the theoretical irradiance distribution to meet the prescribed austenization profile. • The calculated theoretical irradiance distribution is implemented by means of the high-frequency scanning of a Gaussian beam. • Analytical formulas of the equivalence between the high-frequency scanning and the irradiance distribution are demonstrated. • The final laser hardening experimental profile is successfully matched to the predictive material transformation results. [ABSTRACT FROM AUTHOR]