Electronic, dielectric and optical properties of two dimensional and bulk ice: a multi-scale simulation study

The intercalated water into nanopores exhibits anomalous properties such as ultralow dielectric constant.~Multi-scale modeling and simulations are used to investigate the dielectric properties of various crystalline two-dimensional ices and bulk ices. Although, the structural properties of two-dimensional (2D-) ices have been extensively studied, much less is known about their electronic and optical properties. First, by using density functional theory (DFT) and density functional perturbation theory (DFPT), we calculate the key electronic, optical and dielectric properties of 2D-ices. Performing DFPT calculations, both the ionic and electronic contributions of the dielectric constant are computed. The in-plane electronic dielectric constant is found to be larger than the out-of-plane dielectric constant for all the studied 2D-ices. The in-plane dielectric constant of the electronic response is found to be isotropic for all the studied ices. Secondly, we determined the dipolar dielectric constant of 2D-ices using molecular dynamics simulations (MDS) at finite temperature. The total out-of-plane dielectric constant is found to be larger than 2 for all the studied 2D-ices. Within the framework of the random-phase approximation (RPA), the absorption energy ranges for 2D-ices are found to be in the ultraviolet spectra. For the comparison purposes, we also elucidate the electronic, dielectric and optical properties of four crystalline ices (ice VIII, ice XI, ice Ic and ice Ih) and bulk water

Experimental investigation of inlet distortion effect on performance of a micro gas turbine

An experimental study has been carried out to determine how inlet total-pressure distortion affects the performance of a micro gas turbine. An inlet simulator is designed and developed to produce and measure distortion patterns at the inlet to the gas turbine. An air jet distortion generator (AJDG) is used to produce nonuniform flow patterns and total pressure probes are installed to measure steady-state total-pressure distribution at the inlet. A set of wind tunnel tests have been performed to confirm the fidelity of distortion generator and measuring devices. Tests are carried out with the gas turbine exposed to inlet flow with 60¿deg, 120¿deg, and 180¿deg circumferential distortion patterns with different distortion intensities. The performance of the gas turbine has been measured and compared with that of clean inlet flow case. Results indicate that the gas turbine performance can be affected significantly facing with intense inlet distortions.Peer ReviewedPostprint (published version

Protein-based nanoformulations for α-Tocopherol encapsulation

Nanoparticles of bovine serum albumin (BSA) and silk fibroin (SF) with entrapped α-tocopherol were produced via ultrasonic emulsification. Populations with particle size of 200300 nm and highly negatively charged were obtained for all the tested formulations. Entrapment efficiencies of around 99% revealed the effective encapsulation of α-tocopherol into the produced nanoformulations. Generally, these nanodevices did not induce significant cytotoxicity to human skin keratinocytes for all the concentrations tested. The developed formulations showed free radical scavenging of ABTS.+ ability resulting from the synergistic effect between proteins in formulation and the entrapped tocopherol. Overall, the results contribute for the establishment of BSA:VO and BSA:SF:VO as biodegradable and non-toxic nanoformulations for the functionalization of textile devices and controlled delivery of tocopherol into the skin.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE2020 (POCI-01-0145FEDER-006684) and BioTecNorte operation (NORTE-01-0145FEDER-000004) funded by European Regional Development Fund under the scope of Norte 2020-Programa Operacional Regional do Norte. Artur Ribeiro thanks FCT for the SFRH\BPD\98388\2013 grant. Fatemeh Shahmoradi would like to acknowledge the Iran Ministry of Science, Research and Technology (MSRT) for the monetary support.info:eu-repo/semantics/publishedVersio

Numerical and Experimental Investigation of Flow in Partially Filled Sewer Pipes

Complex phenomena in wastewater systems, such as flow pattern in sewers and sediment transport could be investigated in detail using computational fluid dynamics (CFD). However, it is not easy to find an appropriate CFD model for a specific problem. This paper aims to develop and validate a CFD model to correctly predict the free-surface turbulent flow passing through a circular pipe.  In this study, the multiphase model Volume of Fluid (VOF) of the software Ansys-Fluent was used to capture the interface between air and water. Different variants of the k-ε turbulence model of the RANS group and meshing approaches were investigated. To validate the CFD model, a set-up of an acryl-glass pipe in a closed system was constructed under laboratory conditions. The centre-plane velocity profile was used to compare the CFD model results and Laser Doppler Velocimetry (LDV) measurements. Furthermore, the values of the average velocity and shear stress from the experiments were compared to the results of the CFD model. The best results were obtained using a Cutcell mesh combined with the RNG k-ε turbulence model. The validated model was used to investigate the influence of the bed roughness on the velocity and shear stress distribution in partially filled pipes. The velocity decreases while increasing the bed roughness, however the shear stress becomes greater over a rough bed than over a smooth bed

Philosophical-Educational Analysis of Iranian and English Picture-Story Books Based on "Authority and Freedom" Categories

Authority and freedom paradox is one of the most important issues in the philosophy of education as it is in the children's literature. Techniques used by authors of children's literature works, originate from their view on the child. The purpose of this paper is to compare Philosophical-Educational analysis of Iranian and English picture-story books via discovering and investigating the authors' view on "authority and freedom" categories. The research is a kind of exploratory and descriptive research with non-emerging approach to research design. Purposive sampling and documentary method of data collection and interpretive-descriptive method of data analysis were used. Two picture-story books "The Tale of Peter Rabbit" by Beatrix Potter and "Hypa and Shypa's Shoes" by Morteza Khosronejad had been chosen for analysis. The research question is based on Iranian and English authors' viewpoints on "authority and freedom" in the children's literature and comparing them. Revealing the techniques in the works is important for the authors, because they sometimes use these techniques unconsciously. Denuding the techniques can also be considered by critics, parents, teachers, and even children. The results show that the authors' view on the child affects the way of writing books and the use of various techniques. The results also indicate that although they belong to different social and cultural settings, the Iranian and English authors' viewpoints on the child are an independent being that is free, adventurous, vivacious, and able to solve the problems. The authors also are aware of the existence and importance of "authority and freedom" categories in the children's literature. Although Beatrix Potter makes a beautiful balance between the author's authority and the audience's freedom at the end of his story, Khosronejad delicately accepts child freedom beside the adult support and inspection. Keywords: Authority and Freedom paradox, Picture-story Books, Beatrix Potter, Morteza Khosroneja

Freeze-drying of ampicillin solid lipid nanoparticles using mannitol as cryoprotectant

Nanoparticulas lipídicas sólidas (NLSs) são sistemas coloidais de liberação interessantes, uma vez que reúnem todas as vantagens de nanopartículas lipídicas e poliméricas. A liofilização é um processo amplamente utilizado para melhorar a estabilidade das NLSs e os crioprotetores têm sido usados para diminuir a agregação destas durante esse processo. Neste estudo, a ampicilina foi escolhida para ser encapsulada em um carreador de colesterol de escala nanométrica. Para manter a estabilidade das NLSs, a liofilização foi realizada utilizando-se manitol. O tamanho de partícula, o perfil de liberação do fármaco e os efeitos antibacterianos foram estudados após a liofilização em comparação com a NLSs primária. De acordo com os resultados, as preparações que contêm 5% de manitol mostraram o menor aumento do tamanho de partícula. Os resultados de tamanhos médio foram de 150 e 187 nm antes e depois da liofilização, respectivamente. O perfil de liberação prolongada, bem como o efeito antimicrobiano da ampicilina NLSs não foram alterados após a liofilização. A análise por DSC evidenciou provável interação entre a ampicilina e o colesterol.Solid lipid nanoparticles (SLNs) are interesting colloidal drug-delivery systems, since they have all the advantages of the lipid and polymeric nanoparticles. Freeze-drying is a widely used process for improving the stability of SLNs. Cryoprotectants have been used to decrease SLN aggregations during freeze-drying. In this study Ampicillin was chosen to be loaded in a cholesterol carrier with nano size range. To support the stability of SLNs, freeze-drying was done using mannitol. Particle size, drug release profile and antibacterial effects were studied after freeze-drying in comparison with primary SLNs. Preparations with 5% mannitol showed the least particle size enlargement. The average particle size was 150 and 187 nm before and after freeze-drying, respectively. Freeze-drying did not affect the release profile of drug loaded nanopartilces. Also our study showed that lyophilization did not change the antimicrobial effect of ampicillin SLNs. DSC analysis showed probability of chemical interaction between ampicillin and cholesterol

Producing High Strength Aluminum Alloy by Combination of Equal Channel Angular Pressing and Bake Hardening

A combination of severe plastic deformation by equal channel angular pressing (ECAP) and bake hardening (BH) was used to produce high strength ultrafine-grained AA6061 aluminum alloy. 2, 4 and 8 passes of ECAP were performed, and the bake hardenability of samples was tested by 6% pre-straining followed by baking at 200 °C for 20 min. The microstructures obtained for various passes of ECAP were characterized by XRD, EBSD, and TEM techniques. The microstructures were refined from an average grain size of 20 µm to 212 nm after 8 passes of ECAP. Maximum bake hardenability of 110 MPa, and final yield stress of 330 MPa were obtained in the specimens processed by 8 passes of ECAP