Influence of Storage Temperature on Radiochemical Purity of 99mTc-Radiopharmaceuticals

The influence of effective room temperature on the radiochemical purity of 99mTc-radiopharmaceuticals was reported. This study was born from the observation that in the isolators used for the preparation of the 99mTc-radiopharmaceuticals the temperatures can be higher than those reported in the commercial illustrative leaflets of the kits. This is due, in particular, to the small size of the work area, the presence of instruments for heating, the continuous activation of air filtration, in addition to the fact that the environment of the isolator used for the 99mTc-radiopharmaceuticals preparation and storage is completely isolated and not conditioned. A total of 244 99mTc-radiopharmaceutical preparations (seven different types) have been tested and the radiochemical purity was checked at the end of preparation and until the expiry time. Moreover, we found that the mean temperature into the isolator was significantly higher than 25 C, the temperature, in general, required for the preparation and storage of 99mTc-radiopharmaceuticals. Results confirmed the radiochemical stability of radiopharmaceutical products. However, as required in the field of quality assurance, the impact that different conditions than those required by the manufacturer on the radiopharmaceuticals quality have to be verified before human administration

Analysis, Design and Control of a Modular Full-Si Converter Concept for Electric Vehicle Ultra-Fast Charging

L'abstract è presente nell'allegato / the abstract is in the attachmen

Home-Based High-Intensity Interval Training with Heart Failure: A Comparison between Supervised and Unsupervised Modalities

Background: In recent years, both telerehabilitation and high-intensity interval training have been studied in connection with patients with Heart Failure (HF). However, these two variables have never been investigated together. The aim of this study was to investigate exercise intensity, perceived safety and exertion of home-based, high-intensity interval training exercise. Design: A non-randomised cross-over study. Methods: Eleven participants with HF (7 men, 4 women; mean age 63.4 years), from the IT IS HOPE 4 HF study, volunteered to participate. After 3 months of twice weekly, high-intensity interval training via telerehabilitation, the participants were asked to perform the last week of intervention wearing heart rate (HR) monitors during both supervised- (live video-conference telerehabilitation) and unsupervised (pre-recorded video) sessions. The outcome was to determine if there were differences between the supervised- and unsupervised sessions in exercise intensity, perceived safety and exertion levels. Results: Eight participants completed the intervention. No adverse events were reported or recorded. Significant differences were found between supervised- and unsupervised exercise modalities when comparing 2nd (86±16 vs 79±16 %HRpeak, p=0.04), 3rd (86±15 vs 81±15 %HRpeak, p=0.03) and 4th (88±16 vs 81±17 %HRpeak, p=0.01) high-intensity intervals (HIIs) and the 2nd moderate intensity active break (82±17 vs 77±15 %HRpeak, p=0.02). All participants felt safe during every recorded intervention. However, no significant differences were found in perceived safety and exertion levels. Conclusion: Telerehabilitation allowed the participants to reach target exercise intensities, while the unsupervised video sessions, did not. However, after 3 months of training, participants felt safe when training both with- and without supervision

Impact of imaging protocol on left ventricular ejection fraction using gated-SPECT myocardial perfusion imaging

10noopenopenMarcassa, C; Giubbini, R.; Acampa, W.; Cittanti, C.; Djepaxhija, O.; Gimelli, A.; Kokomani, A.; Medolago, G.; Milan, E.; Sciagrà, R.Marcassa, C; Giubbini, Raffaele; Acampa, W.; Cittanti, C.; Djepaxhija, O.; Gimelli, A.; Kokomani, A.; Medolago, Giuseppe; Milan, E.; Sciagrà, R

Modulation Strategy Assessment for 3-Level Unidirectional Rectifiers in Electric Vehicle Ultra-Fast Charging Applications

This paper proposes a complete analysis and comparison of the most significant pulse-width modulation (PWM) strategies for unidirectional 3-level rectifiers. The basic operation of the converter is described and the stresses on the major passive components (i.e. DC-link capacitors, differential-mode inductors, common-mode chokes) are calculated, highlighting the general performance trade-off of each modulation strategy. This analysis is applied to a rectifier for electric vehicle (EV) ultra-fast charging connected to the European low-voltage grid (i.e. 50 Hz, 400 V line-to-line), adopting a 650 V DC-link. The best candidates concerning different performance metrics are identified and the most suitable strategy for EV battery charging is selected

Optimal Design of Grid-Side LCL Filters for Electric Vehicle Ultra-Fast Battery Chargers

This paper proposes a complete design procedure for LCL filters intended for electric vehicle (EV) ultra-fast battery chargers. The basic modeling of LCL filters is reported and the optimal ratio between grid-side and converter-side inductance is discussed. The design methodology is based on the identification of all parameter constraints, which allow to graphically determine the filter design space. Once the available space is identified, the feasible design which minimizes the total required inductance is selected, since inductors dominate the overall LCL filter volume, loss and cost. The proposed design procedure is directly applied to a 50 kW, 20 kHz 3-level unidirectional rectifier for a modular EV ultra-fast charger. The performances of the selected design, in terms of harmonic filtering and current control dynamics, are verified by means of simulation in PLECS environment, proving the validity of the proposed design methodology

Optimal Design of Grid-Side LCL Filters for Electric Vehicle Ultra-Fast Battery Chargers

This paper proposes a complete design procedure for LCL filters intended for electric vehicle (EV) ultra-fast battery chargers. The basic modeling of LCL filters is reported and the optimal ratio between grid-side and converter-side inductance is discussed. The design methodology is based on the identification of all parameter constraints, which allow to graphically determine the filter design space. Once the available space is identified, the feasible design which minimizes the total required inductance is selected, since inductors dominate the overall LCL filter volume, loss and cost. The proposed design procedure is directly applied to a 50 kW, 20 kHz 3-level unidirectional rectifier for a modular EV ultra-fast charger. The performances of the selected design, in terms of harmonic filtering and current control dynamics, are verified by means of simulation in PLECS environment, proving the validity of the proposed design methodology

Electric vehicle ultra-fast battery chargers: A boost for power system stability?

As a consequence of the exponential growth of the electric vehicle (EV) market, DC fast-charging infrastructure is being rapidly deployed all around the world. Ultra-fast charging (UFC) stations are starting to pose serious challenges to the electric power system operation, mostly due to their high peak power demand and unregulated discontinuous operation. To address these issues, local energy storage can be installed, ensuring a smoother grid power absorption profile and allowing to provide grid-supporting features. In this work, a control solution for the grid-side AC/DC converter of next-generation EV UFC stations is proposed. A virtual synchronous compensator (VSC) control algorithm is implemented, in order to lessen the impact of the charging station on the utility and to provide the full spectrum of grid ancillary services (i.e., frequency regulation, reactive power compensation, harmonic reduction, short circuit current generation, etc.). The proposed control strategy is verified experimentally on a downscaled 15 kVA three-phase inverter, emulating the grid front-end of the charging station

Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery Charging

State-of-the-art ultra-fast battery chargers for electric vehicles simultaneously require high efficiency and high power density, leading to a challenging power converter design. In particular, the grid-side filter, which ensures sinusoidal current absorption with low pulse-width modulation (PWM) harmonic content, can be a major contributor to the overall converter size and losses. Therefore, this paper proposes a complete analysis, design and optimization procedure of a three-phase LCL filter for a modular DC fast charger. First, an overview of the basic LCL filter modeling is provided and the most significant system transfer functions are identified. Then, the optimal ratio between grid-side and converter-side inductance is discussed, aiming for the maximum filtering performance. A novel design methodology, based on a graphical representation of the filter design space, is thus proposed. Specifically, several constraints on the LCL filtering elements are enforced, such that all feasible design parameter combinations are identified. Therefore, since in low-voltage high-power applications the inductive components typically dominate the overall filter volume, loss and cost, the viable LCL filter design that minimizes the total required inductance is selected. The proposed design procedure is applied to a 30 kW, 20 kHz 3-level unidirectional rectifier, employed in a modular DC fast charger. The performance of the selected optimal design, featuring equal grid-side and converter-side 175 µH inductors and 15 µF capacitors, is verified experimentally on an active front-end prototype, both in terms of harmonic attenuation capability and current control dynamics. A current total harmonic distortion (THD) of 1.2% is achieved at full load and all generated current harmonics comply with the applicable harmonic standard. Moreover, separate tests are performed with different values of grid inner impedance, verifying the converter control stability in various operating conditions and supporting the general validity of the proposed design methodology

Digital Multi-Loop Control of an LLC Resonant Converter for Electric Vehicle DC Fast Charging

This paper proposes a digital control strategy for LLC resonant converters, specifically intended for EV battery charging applications. Two cascaded control loops, i.e. an external battery voltage loop and an internal battery current loop, are designed and tuned according to analytically derived expressions. Particular attention is reserved to the output current control analysis, due to its extremely non-linear behaviour. The well known seventh-order LLC small-signal model, derived with the extended describing function (EDF) method, is simplified to an equivalent first-order model at the resonance frequency. In theseconditions,whichareproventobethemostunderdamped, the current control loop is tuned taking into account the delays introduced by the digital control implementation. Moreover, the adoption of a look-up table (LUT) in the feed-forward path is proposed to counteract the system non-linearities, ensuring high dynamical performance over the full frequency operating range. Finally, the proposed control strategy and controller design procedure are verified both in simulation and experimentally on a 15 kW LLC converter prototype