Casimir force in critical ternary polymer solutions

Consider a mixture of two incompatible polymers A and B in a common good solvent, confined between two parallel plates separated by a finite distance L. We assume that these plates strongly attract one of the two polymers close to the consolute point (critical adsorption). The plates then experience an effective force resulting from strong fluctuations of the composition. To simplify, we suppose that either plates have the same preference to attract one component (symmetric plates) or they have an opposed preference (asymmetric plates). The force is attractive for symmetric plates and repulsive for asymmetric ones. We first exactly compute the force using the blob model, and find that the attractive and repulsive forces decay similarly to L⁻⁴. To go beyond the blob model that is a mean-field theory, and in order to get a correct induced force, we apply the Renormalization-Group to a φ⁴ -field theory ( φ is the composition fluctuation), with two suitable boundary conditions at the surfaces. The main result is that the expected force is the sum of two contributions. The first one is the mean-field contribution decaying as L⁻⁴, and the second one is the force deviation originating from strong fluctuations of the composition that decreases rather as L⁻³. This implies the existence of some cross-over distance L* ∼ aNφ¹/² ( a is the monomer size, N is the polymerization degree of chains and φ is the monomer volumic fraction), which separates two distance-regimes. For small distances (L L*) the fluctuation force is more important.Розглядається суміш двох несумісних полімерів A і B , що добре розчиняються в спільному розчиннику, вміщена між двома паралельними пластинами, розділеними скінченною відстанню L. Ми вважаємо, що поблизу точки розчинення вони сильно притягають один з двох полімерів (критична адсорбція). При цьому пластини знаходяться під впливом ефективної сили, породженої сильними флуктуаціями суміші. Для спрощення ми припускаємо, що або обидві пластини притягають той самий компонент (симетричні пластини) або вони віддають перевагу різним компонентам (асиметричні пластини). Симетричним пластинам відповідає сила притягання, асиметричним – відштовхування. Спершу ми точно розрахували цю силу, використовуючи краплинну модель, і встановили, що сили притягання і відштовхування загасають подібним чином як L⁻⁴. Щоб вийти поза межі краплинної моделі, яка відповідає наближенню середнього поля, і з метою отримати правильний вигляд індукованої сили, ми застосували ренорм-груповий підхід до теорії поля φ⁴ ( φ – флуктуація суміші) з двома відповідними граничними умовами на поверхнях. У результаті встановлено, що шукана сила є сумою двох вкладів. Перший з них – це вклад середнього поля, що загасає якL⁻⁴, а другий – відхилення, викликане сильними флуктуаціями суміші, що зменшується радше як L⁻³. Це означає, що існує певна відстань кроссоверу L* ∼ aNφ¹/² ( a – розмір мономера, N – ступінь полімеризації ланцюжків і φ – об’ємна частка мономера), що розділяє характерні відстані двох згаданих режимів. На малих відстанях (L L*) більш важливим стає флуктуаційний вклад

OptEEmAL: Decision-Support Tool for the Design of Energy Retrofitting Projects at District Level

Designing energy retrofitting actions poses an elevated number of problems, as the definition of the baseline, selection of indicators to measure performance, modelling, setting objectives, etc. This is time-consuming and it can result in a number of inaccuracies, leading to inadequate decisions. While these problems are present at building level, they are multiplied at district level, where there are complex interactions to analyse, simulate and improve. OptEEmAL proposes a solution as a decision-support tool for the design of energy retrofitting projects at district level. Based on specific input data (IFC(s), CityGML, etc.), the platform will automatically simulate the baseline scenario and launch an optimisation process where a series of Energy Conservation Measures (ECMs) will be applied to this scenario. Its performance will be evaluated through a holistic set of indicators to obtain the best combination of ECMs that complies with user's objectives. A great reduction in time and higher accuracy in the models are experienced, since they are automatically created and checked. A subjective problem is transformed into a mathematical problem; it simplifies it and ensures a more robust decision-making. This paper will present a case where the platform has been tested.This research work has been partially funded by the European Commission though the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No 680676. All related information to the project is available at https://www.opteemal-project.eu

Predicting flow reversals in chaotic natural convection using data assimilation

A simplified model of natural convection, similar to the Lorenz (1963) system, is compared to computational fluid dynamics simulations in order to test data assimilation methods and better understand the dynamics of convection. The thermosyphon is represented by a long time flow simulation, which serves as a reference "truth". Forecasts are then made using the Lorenz-like model and synchronized to noisy and limited observations of the truth using data assimilation. The resulting analysis is observed to infer dynamics absent from the model when using short assimilation windows. Furthermore, chaotic flow reversal occurrence and residency times in each rotational state are forecast using analysis data. Flow reversals have been successfully forecast in the related Lorenz system, as part of a perfect model experiment, but never in the presence of significant model error or unobserved variables. Finally, we provide new details concerning the fluid dynamical processes present in the thermosyphon during these flow reversals

OptEEmAL: Decision-Support Tool for the Design of Energy Retrofitting Projects at District Level

Designing energy retrofitting actions poses an elevated number of problems, as the definition of the baseline, selection of indicators to measure performance, modelling, setting objectives, etc. This is time-consuming and it can result in a number of inaccuracies, leading to inadequate decisions. While these problems are present at building level, they are multiplied at district level, where there are complex interactions to analyse, simulate and improve. OptEEmAL proposes a solution as a decision-support tool for the design of energy retrofitting projects at district level. Based on specific input data (IFC(s), CityGML, etc.), the platform will automatically simulate the baseline scenario and launch an optimisation process where a series of Energy Conservation Measures (ECMs) will be applied to this scenario. Its performance will be evaluated through a holistic set of indicators to obtain the best combination of ECMs that complies with user's objectives. A great reduction in time and higher accuracy in the models are experienced, since they are automatically created and checked. A subjective problem is transformed into a mathematical problem; it simplifies it and ensures a more robust decision-making. This paper will present a case where the platform has been tested.This research work has been partially funded by the European Commission though the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No 680676. All related information to the project is available at https://www.opteemal-project.eu

Prediction of Air Mixing From High Sidewall Diffusers in Cooling Mode: Preprint

Computational fluid dynamics modeling was used to evaluate the performance of high sidewall air supply in cooling mode. The research focused on the design, placement, and operation of air supply diffusers located high on a sidewall and return grilles located near the floor on the same sidewall. Parameters of the study are the supply velocity, supply temperature, diffuser dimensions and room dimensions. Thermal loads characteristic of high performance homes were applied at the walls and room temperature was controlled via a thermostat. The results are intended to provide information to guide the selection of high sidewall supply diffusers to provide proper room mixing for cooling of high performance homes

Thermal Performance of Uninsulated and Partially Filled Wall Cavities: Preprint

Low-rise, wood-framed homes are the most common type of residential structures in the United States. Wood wall construction supports roofs efficiently and provides a stable frame for attaching interior and exterior wall coverings. Wall cavities are prevalent and increase thermal resistance, particularly when they are filled with insulating material. This paper describes detailed computational fluid dynamics modeling to evaluate the thermal performance of uninsulated or partially filled wall cavities and accounts for conduction through framing, convection, and radiation. Parameters are ambient outdoor temperature, cavity surface emissivity, cavity aspect ratio, and insulation height. Understanding the thermal performance of uninsulated or partially insulated wall cavities is essential for conserving energy in residential buildings. The results can serve as input for building energy simulation tools such as DOE2 and EnergyPlus for modeling the temperature dependent energy performance of new and older homes with uninsulated or partially insulated walls

Contribution to the study of pharyngeal, epiglottal and laryngeal consonants

International audienc

Application of the active inductor circuit (AI) based band pass Filter (BPF)

A novel active inductor approach, which can improve the quality-factor, was presented in this report. A current reuse active inductor circuit topology was proposed, which can substantially improve its equivalent inductance. This active inductor was implemented by using a 0.13um- CMOS technology, which gives a maximum quality-factor of 1.45 with a 40 nH at 2.259GHz. An optimized differential topology of an RF active filter and its performances are presented. It make use of negative resistance and fully differential in order to independently tune the central frequency and the quality factor with a minimum power consumption of 1.98 mW. The principle seems to be sufficiently general to be used for other active filters single–ended or differential topologies based on simulated inductors

Targeted first-line therapies for advanced colorectal cancer: A Bayesian meta-analysis

10.18632/oncotarget.20185Oncotarget83966458-6646