Holstein polaron in the presence of disorder

Non-local, inhomogeneous and retarded response observed in experiments is reproduced by introducing the Inhomogeneous Momentum Average (IMA) method to study single polaron problems with disorder in the on-site potential and/or spatial variations of the electron-phonon couplings and/or phonon frequencies. We show that the electron-phonon coupling gives rise to an additional inhomogeneous, strongly retarded potential, which makes instant approximations questionable. The accuracy of IMA is demonstrated by comparison with results from the approximation free Diagrammatic Monte Carlo (DMC) method. Its simplicity allows for easy study of many problems that were previously unaccessible. As an example, we show how inhomogeneities in the electron-phonon coupling lead to nonlocal, retarded response in scanning tunneling microscopy (STM) images.Comment: 4 pages, 3 figure

Optimal Design of a Sustainable Hydrogen Supply Chain Network: Application in an Airport Ecosystem

Hydrogen and fuel cell technologies are one solution foraddressing the challenges that major airports are facing today, such asupward price trends of liquid hydrocarbon fuels, greenhouse gasemission regulations, and stricter noise and air pollutant emissionregulations, especially for on-ground pollution. An airport can also beviewed as the center of a hydrogen ecosystem, around which multiplehydrogen users could be clustered, with cost sharing of hydrogenproduction and storage occurring among users. The main novelty of thepresent work is the design of a hydrogen infrastructure irrigated by theairport ecosystem that satisfies the airport ecosystem energy needs. Forthis purpose, the model development is based on a multiobjectiveoptimization framework designed to consider four echelons: energysources, hydrogen production, transportation, and storage. Themultiperiod problem is then solved using theε-constraint method.Two objective functions are involved, that is, the total daily cost (TDC) of the network and an environmental indicator basedon the global warming potential. The second innovative contribution is to model the demand uncertainty using fuzzy conceptsfor a hydrogen supply chain design. Because hydrogen demand is one the most significant parameters, the uncertainty of thedemand has been considered using a proposed fuzzy linear programming strategy. The solutions are compared with the originalcrisp model, giving more robustness to the proposed approach. This work has been performed in the framework of the Hyportmeta-project and, in particular, within the“H2modeling”project. This paper focuses on a hydrogen airport ecosystem located inthe department of Hautes-Pyrénées (France). However, the developed methodology could be extended to other hydrogenecosystems for which deployment involves a multiperiod multi-objective formulation under an uncertain deman

Investigation of the aerodynamic analysis of super long-span bridges by using ERA-based reduced-order models

Reduced-order models (ROM) are computationally efficient techniques, which have been used widely for predicting unsteady aerodynamic response of airfoils and wings. However, they have not been applied extensively to perform unsteady fluid dynamic analysis of super long-span bridges. This paper discusses the application of a reduced-order computational fluid dynamics (CFD) model based on the eigensystem realization algorithm (ERA) in the aerodynamic analysis of three well-studied long-span bridges. The aerodynamic impulse responses of the Great Belt Bridge (GBB) and Stonecutters and Messina Strait Bridges were used to construct the aerodynamic ROM, and then the aerodynamic forces due to arbitrary inputs and their corresponding flutter derivatives were evaluated and compared to those of the model coupled with an advanced CFD code. Results demonstrate reasonable prediction power and high computational efficiency of the technique that can serve for preliminary design, optimization, and control purposes. The methodology described in this paper has wide application in many civil engineering problems where flexible structures interact with unsteady fluid mechanical phenomen

Efficient predictions of unsteady viscous flows around bluff bodies by aerodynamic reduced order models

This paper describes an efficient reduced order model (ROM) applied in the aerodynamic analysis of bluff bodies. The proposed method, which is based on eigensystem realization algorithm (ERA), uses the impulse response of the system obtained by computational fluid dynamics (CFD) analysis to construct a ROM that can accurately predict the response of the system to any arbitrary input. In order to study the performance of the proposed technique, three different geometries including elliptical and rectangular sections as well as the deck cross section of Great Belt Bridge (GBB) were considered. The aerodynamic coefficients of the impulse responses of the three sections are used to construct the corresponding ROM for each section. Then, the aerodynamic coefficients from an arbitrary sinusoidal input obtained by CFD are compared with the predicted one using the ROM. The results presented illustrate the ability of the proposed technique to predict responses of the systems to arbitrary sinusoidal and other generic inputs, with significant savings in terms of CPU time when compared with most CFD codes. The methodology described in this paper has wide application in many offshore engineering problems where flexible structures interact with unsteady fluid flow, and should be useful in preliminary design, in design optimization, and in control algorithm development

A promising targeting system to enrich irinotecan antitumor efficacy: Folic acid targeted nanoparticles

As folic acid receptors are overexpressed in various cancers including the colon, therefore, nanoparticles of folic acid-polyethylene glycol -poly lactic-co-glycolic acid were fabricated and loaded with irinotecan by emulsification/solvent evaporation technique to target the folic acid receptors in colorectal tumors. The chemical structure of synthesized polymer was examined by 1H NMR, and Box-Behnken design was utilized to determine the combined impact of independent variables for choosing the appropriate formulation. Dynamic light scattering, scanning electron microscope and differential scanning calorimetry (DSC) were utilized to scrutinize irinotecan in nanoparticles. The Box-Behnken design indicated a reasonable correlation between the predicted and experimented values which proves the efficiency of the selected statistical model. The optimized nanoparticles had an acceptable size and morphology. DSC analysis exhibited that irinotecan in nanoparticles is in an amorphous state. The optimized formulation exhibited a prolonged release profile. In addition, the higher drug release from nanoparticles in acidic pH indicates that they can be used to target the extracellular pH of the tumor. The activity of targeted nanoparticles against tumors was higher than the irinotecan and simple nanoparticles. Evaluation of folic acid decorated nanoparticles containing irinotecan confirmed their suitability for targeted delivery of irinotecan in folate positive cancers. © 2021 Elsevier B.V