Search results for " ai"

Primordial dark matter from curvature induced symmetry breaking

2020

We demonstrate that adiabatic dark matter can be generated by gravity induced symmetry breaking during inflation. We study a $Z_2$ symmetric scalar singlet that couples to other fields only through gravity and for which the symmetry is broken by the spacetime curvature during inflation when the non-minimal coupling $\xi$ is negative. We find that the symmetry breaking leads to the formation of adiabatic dark matter with the observed abundance for the singlet mass $m\sim{\rm MeV}$ and $|\xi|\sim 1$.

Shining primordial black holes

2021

We study the well-motivated mixed dark matter (DM) scenario composed of a dominant thermal WIMP, highlighting the case of $SU(2)_L$ triplet fermion "winos", with a small fraction of primordial black holes (PBHs). After the wino kinetic decoupling, the DM particles are captured by PBHs leading to the presence of PBHs with dark minihalos in the Milky Way today. The strongest constraints for the wino DM come from the production of narrow line gamma rays from wino annihilation in the Galactic Center. We analyse in detail the viability of the mixed wino DM scenario, and determine the constraints on the fraction of DM in PBHs assuming a cored halo profile in the Milky Way. We show that already wi…

Despicable dark relics: generated by gravity with unconstrained masses

2019

We demonstrate the existence of a generic, efficient and purely gravitational channel producing a significant abundance of dark relics during reheating after the end of inflation. The mechanism is present for any inert scalar with the non-minimal curvature coupling $\xi R\chi^2$ and the relic production is efficient for natural values $\xi = {\cal O}(1)$. The observed dark matter abundance can be reached for a broad range of relic masses extending from $m \sim 1 {\rm k eV}$ to $m \sim 10^{8} {\rm GeV}$, depending on the scale of inflation and the dark sector couplings. Frustratingly, such relics escape direct, indirect and collider searches since no non-gravitational couplings to visible ma…

Computer-aided design of substrate integrated waveguide filters for microwave and millimeter-wave applications

2009

In this paper, a Computer-Aided Design (CAD) tool of Substrate Integrated Waveguide (SIW) filters for high frequency applications is described. Some synthesis techniques are successfully combined with a fast and accurate full-wave analysis method, thus designing several practical examples of in-line and cross-coupled SIW filters. Prototypes have been manufactured and measured showing good results for different filter topologies. A novel zigzag coupling scheme is proposed for SIW compact filters in order to achieve very restrictive specifications of ultra-wideband (UWB) systems.

Interactive Decision Aids

2011

Decision support systems assist people in making a decision or choosing a course of action in a nonroutine situation that requires judgment (Haubl and Trifts 2000; Kasper 1996). In online webstores, vendors can easily offer highly interactive types of decision support. These co-called interactive decision aids (IDA) “help consumers in making informed purchase decisions amidst the vast availability of online product offerings” (Wang and Benbasat 2009, p. 3). However, the application of IDA is not restricted to purchase decisions. They are general enough to be of use in any kind of choice task where alternatives are known.

The Idea Machine: LLM-based Expansion, Rewriting, Combination, and Suggestion of Ideas

2022

We introduce the Idea Machine, a creativity support tool that leverages large language models (LLMs) to empower people engaged in idea generation tasks. The tool includes a number of affordances that can be used to enable various levels of automation and intelligent support. Each idea entered into the system can be expanded, rewritten, or combined with other ideas or concepts. An idea suggestion mode can also be enabled to make the system proactively suggest ideas.

Contratti a tempo indeterminato

2013

Recesso del consumatore

2013

Surfactant-based enrichment of rare earth elements from NdFeB magnet e-waste: Optimisation of cloud formation and rare earths extraction

2023

Appropriate waste and resource management are essential for a sustainable circular economy with reduced environmental impact. With critical resources, e-waste may serve as indirect raw material. For example, with NdFeB permanent magnets, Neodymium (Nd) and the co-present Dysprosium (Dy) are critical rare earth elements (REEs). However, there exists no economically viable technology for recycling them from electronic waste (e-waste). Here, a method is presented based on cloud point extraction (CPE). The work involves basic complexation chemistry in a cloud medium with pure REE salts, as well as, with real NdFeB-magnets (nearly 28% REE content by weight) from an old hard disk drive (5.2 g mag…

No-touch methods of terminal cleaning in the intensive care unit: results from the first large randomized trial with patient-centred outcomes

2017

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