Search results for "DETA"
showing 10 items of 332 documents
Identifying Drivers of Destination Attractiveness in a Competitive Environment: A Comparison of Approaches
2016
Abstract This study applies a demand-side analysis framework to assess drivers of destination attractiveness in consideration of competitor destinations. The framework, consisting of a relevance–determinance analysis (RDA) and a competitive-performance analysis (CPA), is further benchmarked against competing variants of importance–performance analysis (IPA). As this study reveals, the RDA+CPA framework significantly outperforms the IPA approaches with regard to the level of detail and validity of recommended managerial action. In particular, this study reveals that the original IPA framework of recommendations is not compatible for use with attributes that are characterized by large discrep…
Non-reversible Monte Carlo simulations of spin models
2011
Abstract Monte Carlo simulations are used to study simple systems where the underlying Markov chain satisfies the necessary condition of global balance but does not obey the more restrictive condition of detailed balance. Here, we show that non-reversible Markov chains can be set up that generate correct stationary distributions, but reduce or eliminate the diffusive motion in phase space typical of the usual Monte Carlo dynamics. Our approach is based on splitting the dynamics into a set of replicas with each replica representing a biased movement in reaction-coordinate space. This introduction of an additional bias in a given replica is compensated for by choosing an appropriate dynamics …
Production of hydrogen negative ions in an ECR volume source: balance between vibrational excitation and ionization
2018
International audience; The operation of an ECR-driven (2.45 GHz) hydrogen negative ion source is studied. Electron densities and temperatures are investigated with electrostatic probes and negative ion densities are measured with laser photodetachment. Vacuum ultraviolet irradiance measurements are focused on molecular transitions to the ground state while high-resolution visible emission spectroscopy is used to study the transitions between excited states for both molecules and atoms. The standalone operation of the source is found to be more efficient in higher pressures (12 mTorr) where negative ion densities are as high as 4×109 cm−3. Further investigation on the operation of the sou…
Modeling epitaxial film growth of C$_{60}$ revisited
2020
Epitaxial films evolve on time and length scales that are inaccessible to atomistic computer simulation methods like molecular dynamics (MD). To numerically predict properties for such systems, a common strategy is to employ kinetic Monte Carlo simulations, for which one needs to know the transition rates of the involved elementary steps. The main challenge is thus to formulate a consistent model for the set of transition rates and to determine its parameters. Here, we revisit a well-studied model system, the epitaxial film growth of the fullerene ${\mathrm{C}}_{60}$ on an ordered ${\mathrm{C}}_{60}$ substrate (111). We implement a systematic multiscale approach in which we determine transi…
Oxidation of pentan-2-ol -Part II: Experimental and modeling study
2021
International audience; The oxidation of pentan-2-ol was investigated at high-pressure in a jet-stirred reactor and in a shock tube. Experiments in the JSR were carried out at 10 atm, between 500-1180 K, for five different equivalence ratios of = 0.35, 0.5, 1, 2, 4 and 1000 ppm of fuel, at a constant residence time of 0.7 s. Reactant, product and intermediate species mole fractions were quantified using Fourier transform infrared spectrometry (FTIR) and gas chromatography (GC). Ignition delay times were measured for pentan-2-ol/O 2 mixtures in argon in a shock tube at 20 and 40 bar, in a temperature range of 1070-1460 K and for equivalence ratios of = 0.5, 1 and 2. Ignition delay times of a…
Detailed balance analysis of area de-coupled double tandem photovoltaic modules
2015
Published version of an article in the journal: Applied Physics Letters. Also available from the publisher at: http://dx.doi.org/10.1063/1.4906602 This paper describes how layers of area de-coupled top and bottom cells in photovoltaic tandem modules can increase the efficiency of two-terminal tandem devices. The point of the area de-coupling is to allow the number of top cells to differ from the number of bottom cells. Within each of the layers, the cells can be horizontally series-connected and the layers can then be currentor voltage-matched with each other in a tandem module. Using detailed balance modeling, it is shown that two-terminal tandem modules of this type can achieve the same t…
Dielectric Spectroscopy of Recycled Polylactide
2014
The effects of multiple mechanical recycling on amorphous polylactide (PLA) were simulated by means of five successive injection-grinding cycles. The influence of the induced thermo-mechanical degradation on the dielectric properties of PLA was analysed. The relaxation spectra were studied in terms of the complex dielectric permittivity (ε0 and ε00) and the dielectric loss tangent, tg(d) in the frequency range from 102 to 107 Hz over the temperature interval from 0 C to 140 C. It was possible to distinguish two relaxations zones, one at low temperatures and high frequencies (b relaxation) and another at higher temperatures and lower frequencies (a relaxation). The individual relaxations wer…
On-chip purification via liquid immersion of arc-discharge synthesized multiwalled carbon nanotubes
2016
Arc-discharge synthesized multiwalled carbon nanotubes (AD-MWNT) have been proven to be of high quality, but their use is very limited due to difficulties in obtaining them in a clean and undamaged form. Here, we present a simple method that purifies raw AD-MWNT material in laboratory scale without damage, and that in principle can be scaled up. The method consists of depositing raw AD-MWNT material on a flat substrate and immersing the substrate slowly in water, whereby the surface tension force of the liquid–substrate contact line selectively sweeps away the larger amorphous carbon debris and leaves relatively clean MWNTs on the substrate. We demonstrate the utility of the method by prepa…
Calculation of cost-optimal combination of building materials and technical systems for nZEB single-family house using global cost calculation method
2019
As a rule, during the design stage of a single-family house, only initial costs are taken into account and optimised. Long-term financial calculations are usually not even made. At the same time, total costs to design, build and operate the building show a real difference in expenses while living in this house. In the case of nearly zero energy buildings (nZEBs), this global cost approach becomes especially useful because of the strict requirements of heating and primary energy, as well as the compulsory use of renewable energy sources, requiring more detailed and comprehensive calculations of a cost-optimal set of solutions. In this study, a nZEB single-family house is analysed in detail u…
Brāķēto detaļu skaita samazināšanas metāla apstrādes uzņēmumā "Exigum"
2022
Bakalaura darbā ar inženiertehnisko projektu ir pētīta metālapstrādes uzņēmuma SIA “Exigum” ražošanas process un tā laikā radušās brāķētās detaļas ar mērķi noteikt šo problēmu rašanās iemeslus un ieviest atbilstošus uzlabojumus ražošanas procesā, lai samazinātu brāķēto detaļu rašanās iespējamību. Pētījums ietver informācijas avotu analīzi par biežākajiem iemesliem brāķētajām detaļām metāla detaļu ražošanā izmantojot CNC iekārtas, uzņēmuma statistikas analīzi par brāķētajām detaļām, piemērotāko ražošanas procesu uzlabojumu izvēli, pamatojoties uz uzņēmuma specifiku, šo uzlabojumu ieviešanu uzņēmuma ražošanas procesā uz noteiktu laiku un statistikas salīdzināšanu pirms un pēc uzlabojumu ievie…