Search results for "ground"

Constraints on the spatial variation of Planck constant

2021

AbstractInspired by recently published researches, we present two protocols for setting an upper limit to the claimed variation of$$\hbar $$ħupon the position. The protocols, both within today state of art, involve the use of two delayed laser pulses driving an atom. The distinct positions of the laboratory, due to the Earth motion, affects$$\hbar $$ħand hence the atomic dynamics. The first protocol measures the difference in population of the atomic ground state while the second one the red-shift of the harmonics emitted by the atom in the two moments of the experiment. The protocols improve the reported upper limit of$$\varDelta \hbar /\hbar $$Δħ/ħ. The theory shows that$$\hbar (\varvec{r…

Woven folklore: computers promoting cross-cultural understanding

2004

Multicultural cooperation requires participants to understand the cultural background and identity of all the partners. In this respect, computers provide the cooperation with a new and interesting instrument. A team of students from two schools, one in Tanzania, another in Finland, implemented a multimedia version of an African folklore story. A computer served as a platform for genuine cooperation: the whole team worked on one electronic artefact, despite the geographical distance between the members. The collaborative process helped each participant to clarify his/her own cultural background whilst also becoming acquainted with that of his/her distant partner.

Factors affecting flavor perception in space: Does the spacecraft environment influence food intake by astronauts?

2020

International audience; The intention to send a crewed mission to Mars involves a huge amount of planning to ensure a safe and successful mission. Providing adequate amounts of food for the crew is a major task, but 20 years of feeding astronauts on the International Space Station (ISS) have resulted in a good knowledge base. A crucial observation from the ISS is that astronauts typically consume only 80% of their daily calorie requirements when in space. This is despite daily exercise regimes that keep energy usage at very similar levels to those found on Earth. This calorie deficit seems to have little effect on astronauts who spend up to 12 months on the ISS, but given that a mission to …

Effect of fatigue and gender on kinematics and ground reaction forces variables in recreational runners.

2017

The presence of fatigue has been shown to modify running biomechanics. Overall in terms of gender, women are at lower risk than men for sustaining running-related injuries, although it depends on the factors taken into account. One possible reason for these differences in the injury rate and location might be the dissimilar running patterns between men and women. The purpose of this study was to determine the effect of fatigue and gender on the kinematic and ground reaction forces (GRF) parameters in recreational runners. Fifty-seven participants (28 males and 29 females) had kinematic and GRF variables measured while running at speed of 3.3 m s−1 before and after a fatigue test protocol. T…

Dimers of the Higher-Energy Conformer of Formic Acid: Experimental Observation

2012

We report on the first experimental observation of formic acid dimers composed of two molecules of the higher-energy cis conformer. The cis–cis formic acid dimers are prepared in an argon matrix by selective vibrational excitation of the ground state trans conformer (deuterated form HCOOD) combined with thermal annealing of the matrix at about 30 K. Five cis–cis formic acid dimers are predicted by ab initio calculations (interaction energies from −16.9 to −27.2 kJ molˉ¹), and these structures are used for the assignment of the experimental spectra. Selective vibrational excitation of the obtained cis–cis dimers leads to the formation of several trans–cis dimers, which supports the proposed …

Earthquake ground motion artificial simulations through Fractional Tajimi-Kanai Model

2013

Traduir sota la dictadura franquista, traduir clandestinament: Poesia (1944-1945) i Ariel (1946-1951)

2013

After the Spanish Civil War, Francisco Franco’s dictatorship banned Catalan translations for a decade. But in 1948, Carles Riba’s translation of the Odyssey and Josep Maria Sagarra’s translation of the Divine Comedy were published, albeit with severe restrictions. These restrictions remained virtually unchanged until 1962, when the regime began allowing the publication of Catalan translations without prior censorship. In the 1940s, when the repression was at its fiercest, two clandestine journals in Catalan, Poetry (1944-1945) and Ariel (1946-1951), regularly translated a portion of one of the classics of Western literature, and also published contemporary and avant-garde material as well a…

Magnetic hyperfine spectrum of isolated (199Hg)+ Ions

1978

The (199Hg)+ ions were stored in an RF quadrupole electric field and their ground state hyperfine populations pumped optically using the ion resonance radiation at 1942 A from a (202Hg) isotope enriched lamp. A microwave field at 40.5 GHz was phase-locked to the 1350th harmonic of the output of a frequency synthesizer, referenced to a Cs-beam frequency standard. Using a digital averager, a high background suppression optical system monitored the fluorescence light from the ions. Linewidths on the order of 3 Hz were observed for the “field-independent” 0-0 transition, and a value of 40, 507, 348, 051±50 Hz was deduced for the magnetic hyperfine interval, corrected to zero magnetic field.

Quantum gap and spin-wave excitations in the Kitaev model on a triangular lattice

2017

We study the effects of quantum fluctuations on the dynamical generation of a gap and on the evolution of the spin-wave spectra of a frustrated magnet on a triangular lattice with bond-dependent Ising couplings, analog of the Kitaev honeycomb model. The quantum fluctuations lift the subextensive degeneracy of the classical ground-state manifold by a quantum order-by-disorder mechanism. Nearest-neighbor chains remain decoupled and the surviving discrete degeneracy of the ground state is protected by a hidden model symmetry. We show how the four-spin interaction, emergent from the fluctuations, generates a spin gap shifting the nodal lines of the linear spin-wave spectrum to finite energies.

Predicting breakthrough of vanadium in fixed-bed absorbent columns with complex groundwater chemistries: A multi-component granular ferric hydroxide−…

2020

Granular ferric hydroxide (GFH) is often used for fixed bed adsorbent (FBA) columns in groundwater purification units around the world to remove arsenate contaminations. Groundwater can contain also other toxic (e.g., antimonite and vanadate) and non-toxic oxo-anions (phosphate and silicic acid) that are known to affect FBA lifetimes. Therefore, understanding the breakthrough of toxic compounds intended for removal by FBA is essential to their design, and is important to predict accurately breakthrough curves (BTCs) for FBAs in waterworks to plan future operating costs. Rapid small-scale column tests (RSCCT) and pilot-scale FBA were used to simulate vanadate BTCs for complex groundwater che…