709 research outputs found
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Ultra-broad Mid-IR Supercontinuum Generation in Single, Bi and Tri Layer Graphene Nano-Plasmonic waveguides pumping at Low Input Peak Powers
This article presents four different plasmonic structures using Graphene which yielded an efficient plasmonic mode with low loss for Supercontinuum(SC) generation. At an operating wavelength of 1550 nm in these structures, we generated a multi-octave broadband SC spectrum ranging from 1.5 um-25 um at a low input peak power of 1 W. Due to pumping in the anomalous dispersion region with two Zero Dispersion Wavelengths (ZDWs) and the process of cross phase modulation with soliton fission, red-shifted dispersive waves were generated which led to large broadening from 1.5 um-25 um. Two other Supercontinua ranging from 1-10 um and 0.85-2.2 um also at low input peak powers of 2 W and 0.1 W respectively were generated. These three supercontinua are useful for applications in the fields of biomedical sensors, spectroscopy, fluorescence lifetime imaging and in the design of many other new optical devices. Furthermore, we have also discussed our results on behaviour of Graphene as a metal, even without the negative real value of dielectric constant
Application of Near-Infrared Spectroscopy to statistical control in freeze-drying processes
Batch freeze-drying of pharmaceutical products in vials may result in a high degree of intra-batch variability due to several reasons, e.g. non uniform heating rate in the drying chamber. Therefore, product quality in the final product has to be checked in a statistically significant number of samples, in particular in the stage of process development. Here, Fourier-Transform Near-Infrared Spectroscopy is proposed as a fast, non-destructive technique for an off-line Statistical Quality Control application. At first, results obtained in a batch where product features are satisfactory are used to identify a target quality threshold. Then, a statistical controller is developed in such a way that in a production run it is possible to quickly check if product quality exceeds the desired threshold or not. Two approaches based on multivariate analysis are presented: one employs the Hotelling T2 and Mahalanobis statistics to calculate control charts, the other is an application of Partial Least Squares for discriminant analysis (PLS-DA). Control charts and PLS-DA were trained with samples obtained in a run where sucrose solution was processed and validated in other runs where the final product was known to have the desired qualitative characteristics or not. Overall, out-of-specification samples can be predicted by control charts and PLS-DA with 99% and 98% accuracy respectively. PLS-DA was shown to be able to better identify samples correctly processed, while the control charts where more accurate to identify vials where something went wrong. Focusing on residual moisture of the final product, all samples where it was higher than the target value were always correctly identified
A local field emission study of partially aligned carbon-nanotubes by AFM probe
We report on the application of Atomic Force Microscopy (AFM) for studying
the Field Emission (FE) properties of a dense array of long and vertically
quasi-aligned multi-walled carbon nanotubes grown by catalytic Chemical Vapor
Deposition on a silicon substrate. The use of nanometric probes enables local
field emission measurements allowing investigation of effects non detectable
with a conventional parallel plate setup, where the emission current is
averaged on a large sample area. The micrometric inter-electrode distance let
achieve high electric fields with a modest voltage source. Those features
allowed us to characterize field emission for macroscopic electric fields up to
250 V/m and attain current densities larger than 10 A/cm. FE
behaviour is analyzed in the framework of the Fowler-Nordheim theory. A field
enhancement factor 40-50 and a turn-on field 15 V/m at an inter-electrode distance of 1 m are estimated.
Current saturation observed at high voltages in the I-V characteristics is
explained in terms of a series resistance of the order of M. Additional
effects as electrical conditioning, CNT degradation, response to laser
irradiation and time stability are investigated and discussed
Vacuum freeze-drying effect on bioactive compounds of eggplant (Solanum Melongena L.).
Vacuum Freeze Drying (VFD) is a low temperature drying technique that may be used for food preservation. The aim of this work is to evaluate how VFD operating conditions affect eggplants bioactive compounds loss after drying. Samples were freeze-dried under different pressure and temperature conditions, and had their ascorbic acid, total polyphenol and antioxidant capacity percent loss measured after processing. Under the tested conditions, lower temperatures resulted in lower antioxidant capacity in the final product, while lower chamber pressures resulted in lower total polyphenol content
Diffuse interface modeling of eggplants vacuum freeze-drying process
Vacuum freeze-drying (VFD) can be used for preserving food with small effects on nutritional qualities. VFD modelling is useful to select off-line the best operating conditions to avoid product overheating and reduce the drying time, thus saving energy. A 3D diffuse interface model was developed to simulate in-silico eggplant VFD. By comparing the experimental drying time and product temperature, heat transfer coefficient and vapor diffusivity were estimated under different operating conditions
An Improved Integrated Hash and Attributed based Encryption Model on High Dimensional Data in Cloud Environment
Cloud computing is a distributed architecture where user can store their private, public or any application software components on it. Many cloud based privacy protection solutions have been implemented, however most of them only focus on limited data resources and storage format. Data confidentiality and inefficient data access methods are the major issues which block the cloud users to store their high dimensional data. With more and more cloud based applications are being available and stored on various cloud servers, a novel multi-user based privacy protection mechanism need to design and develop to improve the privacy protection on high dimensional data. In this paper, a novel integrity algorithm with attribute based encryption model was implemented to ensure confidentiality for high dimensional data security on cloud storage. The main objective of this model is to store, transmit and retrieve the high dimensional cloud data with low computational time and high security. Experimental results show that the proposed model has high data scalability, less computational time and low memory usage compared to traditional cloud based privacy protection models
Bridging tools to better understand environmental performances and raw materials supply of traction batteries in the future EU fleet
Sustainable and smart mobility and associated energy systems are key to decarbonise the EU and develop a clean, resource efficient, circular and carbon-neutral future. To achieve the 2030 and 2050 targets, technological and societal changes are needed. This transition will inevitably change the composition of the future EU fleet, with an increasing share of electric vehicles (xEVs). To assess the potential contribution of lithium-ion traction batteries (LIBs) in decreasing the environmental burdens of EU mobility, several aspects should be included. Even though environmental assessments of batteries along their life-cycle have been already conducted using life-cycle assessment, a single tool does not likely provide a complete overview of such a complex system. Complementary information is provided by material flow analysis and criticality assessment, with emphasis on supply risk. Bridging complementary aspects can better support decision-making, especially when different strategies are simultaneously tackled. The results point out that the future life-cycle GWP of traction LIBs will likely improve, mainly due to more environmental-friendly energy mix and improved recycling. Even though second-use will postpone available materials for recycling, both these end-of-life strategies allow keeping the values of materials in the circular economy, with recycling also contributing to mitigate the supply risk of Lithium and Nickel
The warm glow of kindness: Developmental insight into children's moral pride across cultures and its associations with prosocial behavior
Moral pride is a key component of virtue development. This study provides developmental insight into children's moral pride across cultures, and the potential for moral pride to underlie prosocial behavior. Participants included children and adolescents ages 6, 9, and 12 years from Canada (n = 186; 50% girls; ethnically diverse sample), Japan (n = 180; 48% girls), and a subsample from Italy (n = 86; 54% girls), as well as their primary caregivers or teachers. Moral pride was measured using a vignette procedure wherein children reported their emotions, emotion intensities, and reasoning following moral actions (harm omission and prosocial contexts). Global prosocial behavior was assessed via caregiver reports. Results revealed that moral pride increased from 6 to 9 years of age in Japanese and Canadian children (some similar trends were found in the Italian subsample) and that Canadian children reported stronger feelings of moral pride than Japanese children (Italian children's moral pride intensities were akin to those of Canadian children). Moral pride was positively associated with global prosocial behavior in Japanese children (and marginally in Italian children) but not in the Canadian children. These novel findings showcase the role of culture in shaping children's moral pride, and the potential for this moral emotion to reinforce children's commitment to prosocial action in childhood and early adolescence
Emphysematous cystitis: An unusual disease of the Genito-Urinary system suspected on imaging
Emphysematous cystitis is a rare disease entity caused by gas fermenting bacterial and fungal pathogens. Clinical symptoms are nonspecific and diagnostic clues often arise from the unanticipated imaging findings. We report a case of 52-year-old male who presented with fever, dysuria and gross hematuria who was found to have emphysematous cystitis
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