Nonlinear energy harvesting Cottone, F; Vocca, H; Gammaitoni, L
Physical review letters,
02/2009, Letnik:
102, Številka:
8
Journal Article
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Ambient energy harvesting has been in recent years the recurring object of a number of research efforts aimed at providing an autonomous solution to the powering of small-scale electronic mobile ...devices. Among the different solutions, vibration energy harvesting has played a major role due to the almost universal presence of mechanical vibrations. Here we propose a new method based on the exploitation of the dynamical features of stochastic nonlinear oscillators. Such a method is shown to outperform standard linear oscillators and to overcome some of the most severe limitations of present approaches. We demonstrate the superior performances of this method by applying it to piezoelectric energy harvesting from ambient vibration.
Most popular statistical models in epidemic evolution focus on the dynamics of average relevant quantities and overlooks the role of small fluctuations on the model parameters. Models for Covid-19 ...are no exception. In this paper we show that the role of time-correlated fluctuations, far from being negligible, can in fact determine the spreading of an epidemic and, most importantly, the resurgence of the exponential diffusion in the presence of time-limited episodes in promiscuity behaviours. The results found in this work are not only relevant and specific for the Covid-19 epidemic but are more general and can be applied to other epidemics.
It has been believed that the superinsulating state, which is the low-temperature charge Berezinskii-Kosterlitz-Thouless (BKT) phase, can exist only in two dimensions. We develop a general gauge ...description of the superinsulating state and the related deconfinement transition of Cooper pairs and predict the existence of the superinsulating state in three dimensions (3d). We find that 3d superinsulators exhibit Vogel-Fulcher-Tammann (VFT) critical behavior at the phase transition. This is the 3d string analog of the Berezinski-Kosterlitz-Thouless (BKT) criticality for logarithmically and linearly interacting point particles in 2d. Our results show that singular exponential scaling behaviors of the BKT type are generic for phase transitions associated with the condensation of topological excitations.
Recent studies propose dry reforming as a potential alternative to steam reforming. A number of advantages come mainly from the substitution of steam with CO2, representing a potential strategy for ...CO2 and waste heat reuse in both carbon-intensive industry (e.g. steel) and power generation applications (e.g. dry reforming coupling to solid oxide fuel cells).
The objective of this study is the development, by means of an ultrasound assisted synthesis technique, of a novel 15%Ni -6%ZrO2 –3%CaO -Al2O3 catalyst with high surface area and metal dispersion, to achieve high values of methane conversion and stable performance, obtained by significantly limiting carbon deposition at temperature in the range 700–750 °C. In this range, compatible with the dry reformer-SOFC thermal integration, conventional catalysts seriously suffer from coking tolerance issues.
The catalyst exhibited very promising results with high methane conversion rates of 93% at 750 °C and 1.25 CO2/CH4 ratio at the reactor inlet (dilution: in SiC 4:1 in volume), stable over 450 h of operation, with no significant changes in outlet gas composition and relevant modifications on material structure as revealed by SEM/EDX, XRD and Raman, analysis.
•Ni–5%CaO–5%ZrO2/Al2O3with high Ni dispertion thanks to US-assisted synthesis.•High Methane conversion.•Long time stability in the range at 750 °C.•Low carbon coke deposition due to effects of CaO and ZrO2.•System integration between a dry reforming reactor and a SOFC system.
Purpose of our study was to explore a new immunotherapy for high grade soft tissue sarcomas (STS) based on cytokine-induced killer cells (CIK) redirected with a chimeric antigen receptor (CAR) ...against the tumor-promoting antigen CD44v6. We aimed at generating bipotential killers, combining the CAR specificity with the intrinsic tumor-killing ability of CIK cells (CAR
+
.CIK). We set a patient-derived experimental platform. CAR
+
.CIK were generated by transduction of CIK precursors with a lentiviral vector encoding for anti-CD44v6-CAR. CAR
+
.CIK were characterized and assessed in vitro against multiple histotypes of patient-derived STS. The anti-sarcoma activity of CAR
+
.CIK was confirmed in a STS xenograft model. CD44v6 was expressed by 40% (11/27) of patient-derived STS. CAR
+
.CIK were efficiently expanded from patients (n = 12) and killed multiple histotypes of STS (including autologous targets, n = 4). The killing activity was significantly higher compared with unmodified CIK, especially at low effector/target (E/T) ratios: 98% vs 82% (E/T = 10:1) and 68% vs 26% (1:4), (p<0.0001). Specificity of tumor killing was confirmed by blocking with anti-CD44v6 antibody. CAR
+
.CIK produced higher amounts of IL6 and IFN-γ compared to control CIK. CAR
+
.CIK were highly active in mice bearing subcutaneous STS xenografts, with significant delay of tumor growth (p<0.0001) without toxicities.
We report first evidence of CAR
+
.CIK's activity against high grade STS and propose CD44v6 as an innovative target in this setting. CIK are a valuable platform for the translation of CAR-based strategies to challenging field of solid tumors. Our findings support the exploration of CAR
+
.CIK in clinical trials against high grade STS.
In modern computers, computation is performed by assembling together sets of logic gates. Popular gates like AND, OR and XOR, processing two logic inputs and yielding one logic output, are often ...addressed as irreversible logic gates, where the sole knowledge of the output logic value is not sufficient to infer the logic value of the two inputs. Such gates are usually believed to be bounded to dissipate a finite minimum amount of energy determined by the input-output information difference. Here we show that this is not necessarily the case, by presenting an experiment where a OR logic gate, realized with a micro-electromechanical cantilever, is operated with energy well below the expected limit, provided the operation is slow enough and frictional phenomena are properly addressed.
Nonlinear bistable systems have proven to be advantageous for energy harvesting of random and real ambient vibrations. One simple way of implementing a bistable transducer is setting a piezoelectric ...beam in a post-buckled configuration by axial compression. Besides, hinged or clamped-clamped type of boundary conditions correspond to two different post-buckled shape functions. Here we study, through theoretical analysis and numerical simulations, the efficiency of a hinged and clamped-clamped piezoelectric bridge under band-limited random noise with progressive axial load. Clamped configuration results to harvest 26% more power than hinged around an optimal axial load of 0.05%, while, in the intra-well trapped situation, above 0.1%, the two configurations present no substantial difference. Nevertheless, simulations confirm the advantage of exploiting inter-well oscillations in bistable regime.
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