7,164 research outputs found
Second Law Analysis of Al2O3-Water Nanofluid Turbulent Forced Convection in a Circular Cross Section Tube with Constant Wall Temperature:
The present paper proposes an analysis based on the second principle of thermodynamics applied to a water-Al 2 O 3 nanofluid. The nanofluid flows inside a circular section tube subjected to constant wall temperature. The aim of the investigation is to understand, by means of an analytical model, how entropy generation within the tube varies if inlet conditions, particles concentration, and dimensions are changed. To gather these information is of fundamental importance, in order to optimize the nanofluid flow. The results show that according to the inlet condition, there is a substantial variation of the entropy generation, particularly when Reynolds number is kept constant there is an increase of entropy generation, whereas when mass flow rate or velocity are taken constant, entropy generation decreases
Experimental and numerical investigation on forced convection in circular tubes with nanofluids
This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.In this paper an experimental and numerical study to investigate the convective heat transfer
characteristics of fully developed turbulent flow of a water–Al2O3 nanofluid in a circular tube is presented.
The numerical simulations are accomplished on the experimental test section configuration. In the analysis,
the fluid flow and the thermal field are assumed axial-symmetric, two-dimensional and steady state. The
single-phase model is employed to model the nanofluid mixture and k-ε model is used to describe the
turbulent fluid flow. Experimental and numerical results are carried out for different volumetric flow rates
and nanoparticles concentration values. Heat transfer convective coefficients as a function of flow rates and
Reynolds numbers are presented. The results indicate that the heat transfer coefficients increase for all
nanofluids concentrations compared to pure water at increasing volumetric flow rate. Heat transfer
coefficient increases are observed at assigned volumetric flow rate for nanofluid mixture with higher
concentrations whereas Nusselt numbers present lower values than the ones for pure water
Digital technologies for behavioral change in sustainability domains: a systematic mapping review
Sustainability research has emerged as an interdisciplinary area of knowledge about how to achieve sustainable development, while political actions toward the goal are still in their infancy. A sustainable world is mirrored by a healthy environment in which humans can live without jeopardizing the survival of future generations. The main aim of this contribution was to carry out a systematic mapping (SM) of the applications of digital technologies in promoting environmental sustainability. From a rigorous search of different databases, a set of more than 1000 studies was initially retrieved and then, following screening criteria based on the ROSES (RepOrting standards for Systematic Evidence Syntheses) procedure, a total of N = 37 studies that met the eligibility criteria were selected. The studies were coded according to different descriptive variables, such as digital technology used for the intervention, type of sustainable behavior promoted, research design, and population for whom the intervention was applied. Results showed the emergence of three main clusters of Digital Technologies (i.e., virtual/immersive/augmented reality, gamification, and power-metering systems) and two main Sustainable Behaviors (SBs) (i.e., energy and water-saving, and pollution reduction). The need for a clearer knowledge of which digital interventions work and the reasons why they work (or do not work) does not emerge from the outcomes of this set of studies. Future studies on digital interventions should better detail intervention design characteristics, alongside the reasons underlying design choices, both behaviourally and technologically. This should increase the likelihood of the successful adoption of digital interventions promoting behavioral changes in a more sustainable direction
Advancing knowledge and treatment of severe fatigue in breast cancer survivors with a focus on cognitive behavioral therapy
Contains fulltext :
187334.pdf (publisher's version ) (Open Access)Radboud University, 11 april 2018Promotores : Rovers, M.M., Knoop, J.A.
Co-promotores : Gielissen, M.F.M., Verhagen, C.A.H.H.V.M.223 p
Composition influence on pulmonary delivery of rifampicin liposomes
The effects of lipid concentration and composition on the physicochemical properties, aerosol performance and in vitro toxicity activity of several rifampicin-loaded liposomes were investigated. To this purpose, six liposome formulations containing different amounts of soy phosphatidylcholine and hydrogenated soy phosphatidylcholine, with and without cholesterol and oleic acid, were prepared and fully characterized. Uni- or oligo-lamellar, small (~100 nm), negatively charged (~60 mV) vesicles were obtained. Lipid composition affected aerosol delivery features of liposomal rifampicin; in particular, the highest phospholipid concentration led to a better packing of the vesicular bilayers with a consequent higher nebulization stability. The retention of drug in nebulized vesicles (NER%) was higher for oleic acid containing vesicles (55% ± 1.4%) than for the other samples (~47%). A549 cells were used to evaluate intracellular drug uptake and in vitro toxicity activity of rifampicin-loaded liposomes in comparison with the free drug. Cell toxicity was more evident when oleic acid containing liposomes were used
Random template placement and prior information
In signal detection problems, one is usually faced with the task of searching
a parameter space for peaks in the likelihood function which indicate the
presence of a signal. Random searches have proven to be very efficient as well
as easy to implement, compared e.g. to searches along regular grids in
parameter space. Knowledge of the parameterised shape of the signal searched
for adds structure to the parameter space, i.e., there are usually regions
requiring to be densely searched while in other regions a coarser search is
sufficient. On the other hand, prior information identifies the regions in
which a search will actually be promising or may likely be in vain. Defining
specific figures of merit allows one to combine both template metric and prior
distribution and devise optimal sampling schemes over the parameter space. We
show an example related to the gravitational wave signal from a binary inspiral
event. Here the template metric and prior information are particularly
contradictory, since signals from low-mass systems tolerate the least mismatch
in parameter space while high-mass systems are far more likely, as they imply a
greater signal-to-noise ratio (SNR) and hence are detectable to greater
distances. The derived sampling strategy is implemented in a Markov chain Monte
Carlo (MCMC) algorithm where it improves convergence.Comment: Proceedings of the 8th Edoardo Amaldi Conference on Gravitational
Waves. 7 pages, 4 figure
Control of skin damages caused by oxidative stress using mangiferin and naringin co-loaded in phospholipid vesicles
Mangiferin and naringin, two naturally occurring antioxidant molecules, were co-loaded in phospholipid vesicles designed for skin delivery. Ultradeformable-liposomes containing tween 80 as edge activator, were used as basic formulation, which was modified adding glycerol (glycerosomes) or a mixture of glycerol and ethanol (etglycerosomes) and further enriched with a polymer, sodium hyaluronate (glycerohyalurosomes and etglycerohyalurosomes), to evaluate the role of vesicle composition on their features and performances. Mean dimeter, polydispersity index and zeta potential of prepared vesicles were measured along with their stabilitcay on storage for 90 days, rheological behavior and suitability as systems for the delivery of these active molecules into and through the skin. Vesicles enriched with sodium hyaluronate were the most stable and the smallest and favored the deposition of both mangiferin and naringin in the whole skin, in a better extent than those without polymer. All the vesicles were highly biocompatible and capable of protecting fibroblasts against hydrogen peroxide-induced oxidative damages in vitro. Once more, glycerohyalurosomes and et-glycerohyalurosomes where those which improved the most the beneficial effect of mangiferin and naringin, as they were capable of effectively counteracting the formation of skin lesion, or even promoting the wound healing, thanks to their greater ability to inhibit both myeloperoxydase activity and oedema formation in vivo in a model mouse in which wound was induced using phorbol acetate
Nano-Derived Therapeutic Formulations with Curcumin in Inflammation-Related Diseases
Due to its vast therapeutic potential, the plant-derived polyphenol curcumin is utilized in an ever-growing number of health-related applications. Here, we report the extraction methodologies, therapeutic properties, advantages and disadvantages linked to curcumin employment, and the new strategies addressed to improve its effectiveness by employing advanced nanocarriers. The emerging nanotechnology applications used to enhance CUR bioavailability and its targeted delivery in specific pathological conditions are collected and discussed. In particular, new aspects concerning the main strategic nanocarriers employed for treating inflammation and oxidative stress-related diseases are reported and discussed, with specific emphasis on those topically employed in conditions such as wounds, arthritis, or psoriasis and others used in pathologies such as bowel (colitis), neurodegenerative (Alzheimer's or dementia), cardiovascular (atherosclerosis), and lung (asthma and chronic obstructive pulmonary disease) diseases. A brief overview of the relevant clinical trials is also included. We believe the review can provide the readers with an overview of the nanostrategies currently employed to improve CUR therapeutic applications in the highlighted pathological conditions.N.C.-M. acknowledges the Portuguese Foundation for Science and Technology under the Horizon 2020 Program (PTDC/PSI-GER/28076/2017). This work was supported by the CONICYT PIA/APOYO CCTE AFB170007, Seed #2001050151 and Collaborative #2101050160—University of Sharjah and Fondo di Ateneo per la Ricerca 2020, University of Sassari
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