Search results for "FLUID"

Experimental evidence on microwave induced electron losses from ECRIS plasma

2018

The balance between warm and hot (>1 keV) electron density and their losses from the magnetic confinement system of an Electron Cyclotron Resonance Ion Source (ECRIS) plasma is considered to be one of the main factors determining the rate of the high charge state ion production. One of the key loss channels for heated electrons is thought to be induced by the injected microwaves. While this loss mechanism, referred to as rf-induced pitch angle scattering, has been studied theoretically and with computational tools, direct experimental evidence of its significance in minimum-B ECRIS plasmas remains limited. In this work, experimental evidence of microwave induced electron losses in the axial…

Feromagnētiskas nanodaļiņas un to pielietojums mīkstu materiālu (dihidropiridīna tipa lipīdu organiski savienojumi, polimēri) funkcionalizācijai

2014

Elektroniskā versija nesatur pielikumus

Magnētiskā mikrokonvekcija mikrofluidikā

2017

Darbā pētīta magnētiskā šķidruma un ūdens sajaukšanās magnētiskās mikrokonvekcijas dēļ mikrofluidikas kanāliņā, kurā šķidrumi tiek ievadīti ar dažādiem plūsmas ātrumiem pie dažādām magnētisko lauku vērtībām. Pētījuma veikšanai izveidota jauna eksperimentālā iekārta kvantitatīvai eksperimentu novērošanai, ieskaitot mikrofluidikas kanāliņu izveidi. Darbā noteikta sakarība starp kritisko magnētisko lauku, pie kā rodas nestabilitāte, šķidrumu ievades ātrumiem. Rezultāti parāda esošā teorētiskā modeļa nepilnību. Tāpat raksturota parādības izmantošana šķidrumu sajaukšanās veicināšanai, iezīmējot iespējas mikrokonvekciju izmantot pielietojumos biomedicīnā.

Modeling biomass char gasification kinetics for improving prediction of carbon conversion in a fluidized bed gasifier

2014

Gasification of biomass in a fluidized bed (FB) was modeled based on kinetic data obtained from previously conducted thermo- gravimetic analysis. The thermogravimetric analysis experiments were designed to closely resemble conditions in a real FB gasifier by using high sample heating rates, in situ devolatilization and gas atmospheres of H 2 O / H 2 and CO 2 / CO mixtures. Several char kinetic models were evaluated based on their ability to predict char conversion based on the thermogravimetric data. A modified version of the random pore model was shown to provide good fitting of the char reactivity and suitability for use in a reactor model. An updated FB reactor model which incorporates t…

The stress-strain state and stabilization of viscoelastoplastic, imperfect moving web continuum

2014

A coupled discontinuous Galerkin-Finite Volume framework for solving gas dynamics over embedded geometries

2021

Author(s): Gulizzi, Vincenzo; Almgren, Ann S; Bell, John B | Abstract: We present a computational framework for solving the equations of inviscid gas dynamics using structured grids with embedded geometries. The novelty of the proposed approach is the use of high-order discontinuous Galerkin (dG) schemes and a shock-capturing Finite Volume (FV) scheme coupled via an $hp$ adaptive mesh refinement ($hp$-AMR) strategy that offers high-order accurate resolution of the embedded geometries. The $hp$-AMR strategy is based on a multi-level block-structured domain partition in which each level is represented by block-structured Cartesian grids and the embedded geometry is represented implicitly by a…

Rhombi-chain Bose-Hubbard model: Geometric frustration and interactions

2018

We explore the effects of geometric frustration within a one-dimensional Bose-Hubbard model using a chain of rhombi subject to a magnetic flux. The competition of tunnelling, self-interaction and magnetic flux gives rise to the emergence of a pair-superfluid (pair-Luttinger liquid) phase besides the more conventional Mott-insulator and superfluid (Luttinger liquid) phases. We compute the complete phase diagram of the model by identifying characteristic properties of the pair-Luttinger liquid phase such as pair correlation functions and structure factors and find that the pair-Luttinger liquid phase is very sensitive to changes away from perfect frustration (half-flux). We provide some propo…

The relationship between children‘s reading ability, verbal and fluid intelligence and measurements of eye movements during reading

2014

The aim of this study was to clarify, which of the following two measures: verbal intelligence or measurements of eye movements, is better predictor of reading ability. In addition, the study also investigated the relationships between reading ability, fluid intelligence and measurements of eye movements. Participants of the study (N = 28; mean age = 8.80; SD = .41; 54% boys) were assessed in reading with LMST-I Reading achievement test, verbal and fluid intelligence was measured using two scales – Verbal Comprehension and Perceptual reasoning – from Latvian edition of Wechsler Intelligence Scale for Children Fourth Edition (WISC- IV, Latvian version), as well as eye tracking was made durin…

Robustness of asymmetry and coherence of quantum states

2016

Quantum states may exhibit asymmetry with respect to the action of a given group. Such an asymmetry of states can be considered as a resource in applications such as quantum metrology, and it is a concept that encompasses quantum coherence as a special case. We introduce explicitly and study the robustness of asymmetry, a quantifier of asymmetry of states that we prove to have many attractive properties, including efficient numerical computability via semidefinite programming, and an operational interpretation in a channel discrimination context. We also introduce the notion of asymmetry witnesses, whose measurement in a laboratory detects the presence of asymmetry. We prove that properly c…

Fundamental bounds on qubit reset

2020

Qubit reset is a basic prerequisite for operating quantum devices, requiring the export of entropy. The fastest and most accurate way to reset a qubit is obtained by coupling the qubit to an ancilla on demand. Here, we derive fundamental bounds on qubit reset in terms of maximum fidelity and minimum time, assuming control over the qubit and no control over the ancilla. Using the Cartan decomposition of the Lie algebra of qubit plus two-level ancilla, we identify the types of interaction and controls for which the qubit can be purified. For these configurations, we show that a time-optimal protocol consists of purity exchange between qubit and ancilla brought into resonance, where the maximu…