Search results for " engineering"
showing 10 items of 38291 documents
Oxidation-responsive and "clickable" poly(ethylene glycol) via copolymerization of 2-(methylthio)ethyl glycidyl ether
2016
Poly(ethylene glycol) (PEG) is a widely used biocompatible polymer. We describe a novel epoxide monomer with methyl-thioether moiety, 2-(methylthio)ethyl glycidyl ether (MTEGE), which enables the synthesis of well-defined thioether-functional poly(ethylene glycol). Random and block mPEG-b-PMTEGE copolymers (Mw/Mn = 1.05-1.17) were obtained via anionic ring opening polymerization (AROP) with molecular weights ranging from 5 600 to 12 000 g·mol-1. The statistical copolymerization of MTEGE with ethylene oxide results in a random microstructure (rEO = 0.92 ± 0.02 and rMTEG E = 1.06 ± 0.02), which was confirmed by in situ 1H NMR kinetic studies. The random copolymers are thermorespon…
Investigation of Nonlinear Optical Processes in Mercury Sulfide Quantum Dots
2022
European Regional Development Fund (1.1.1.5/19/A/003), State Assignment to Higher Educational Institutions of Russian Federation (FZGU-2020-0035), Russian Foundation for Basic Research (18-29-20062). Institute of Solid State Physics, University of Latvia as the Center of Excellence acknowledges funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART2.
Overview of Power Electronic Switches: A Summary of the Past, State-of-the-Art and Illumination of the Future.
2020
As the need for green and effective utilization of energy continues to grow, the advancements in the energy and power electronics industry are constantly driven by this need, as both industries are intertwined for obvious reasons. The developments in the power electronics industry has over the years hinged on the progress of the semiconductor device industry. The semiconductor device industry could be said to be on the edge of a turn into a new era, a paradigm shift from the conventional silicon devices to the wide band gap semiconductor technologies. While a lot of work is being done in research and manufacturing sectors, it is important to look back at the past, evaluate the current progr…
Applying Semiautomatic Generation of Conceptual Models to Decision Support Systems Domain
2009
This paper presents a decision support system specification in the form of business use cases and a stereotyped conceptual model based on the specification. The use cases are based on generic user requirements and address cognitive biases. The specification can be used to set fixed and common terms among the project participants. Semiautomatic generation of the conceptual model is demonstrated with mixed results. While there are some shortcomings in the parsing and the result is dependent on the phrasing conventions used in the use cases, the conceptual model highlights the most essential entities in the domain and provides a base for further development phases. peerReviewed
A Study on the Assessment of Introductory Computational Thinking via Scratch Programming in Primary Schools
2018
Computational thinking (CT), a transversal intellectual foundation integral to computer science, is making its way into compulsory comprehensive education worldwide. Students are expected to attain skills and knowledge in such interdisciplinary CT principles as Algorithmic thinking, Data representation, and Debugging. Problem-solving by designing and manipulating interactive media with Scratch, a graphical programming tool, is popular especially at the primary school level. However, there has been confusion regarding how introductory CT can be operationalized for educational practice. Teachers and students need research-based knowledge for setting appropriate learning goals in addition to i…
Progress in HAXPES performance combining full-field k-imaging with time-of-flight recording
2019
Journal of synchrotron radiation 26(6), 1996-2012 (2019). doi:10.1107/S1600577519012773
Estimation of the Time-Variant Velocity of a Single Walking Person in Two-Dimensional Non-Stationary Indoor Environments Using Radio-Frequency Techni…
2020
Accurate estimation of the time-variant (TV) velocity of moving persons/objects in indoor spaces is of crucial importance for numerous wireless indoor applications. This article introduces a novel iterative procedure to estimate the TV velocity, i.e., TV speed and TV angle-of-motion (AOM), of a single moving person in 2D indoor environments by using radio-frequency (RF) techniques. The indoor area is equipped with a distributed 2 × 2 multiple-input multiple-output (MIMO) system. The proposed method is divided into two parts. In the first part, we estimate the path gains and the instantaneous Doppler frequencies by fitting the exact spectrograms of the complex channel gains of a 2D no…
Fractional viscoelastic transversally isotropic Timoshenko beam
2014
In this paper the viscoelastic behavior of pultruded beams has been examined. Pultruded beams are constituted by a polymer infilled with reinforcement in longitudinal direction, while in the orthogonal direction no fiber are present for technological reasons. As a consequence the material has two different behaviors in longitudinal and in orthogonal directions. It follows that pultruded beams are transversally isotropic, and the shear deformation may not be neglected. Based upon the previous observations and assuming for Creep and/or Relaxation test the power law, the constitutive equations are ruled by fractional operators. From constitutive laws, and assuming the Timoshenko beam theory to…
Characterization of a novel three-dimensional outgrowth model of human bronchial mucosa
2011
Recently it has been hypothesized that a reactivation of the epithelial-mesenchymal trophic unit (EMTU) of the respiratory mucosa, caused by extensive epithelial damage, may be responsible for the pathogenesis of asthma. However, most research on this subject so far has been limited by the unavailability of in vitro models correctly mimicking the three-dimensional architecture of the properly differentiated human bronchial mucosa. For this reason, we have developed a novel 3D outgrowth model, obtained from bronchial biopsies and composed of both human bronchial epithelial cells (goblet and columnar cells) and fibroblasts with their basement membrane. Here we present the preliminary data obt…