3,813 research outputs found
An educational game to teach children about air quality using augmented reality and tangible interaction with sensors
Air pollution is known to be one of the main causes of injuries to the respiratory system and even premature death. Gases, particles, and biological compounds affect not only the air we breathe outdoors, but also indoors. Children are highly affected by the poor quality of the air they breathe because their organs and immune systems are still in the developmental stages. To contribute to raising children’s awareness to these concerns, this article presents the design, implementation, and experimental validation of an serious augmented reality game for children to playfully learn about air quality by interacting with physical sensor nodes. The game presents visual representations of the pollutants measured by the sensor node, rendering tangible the invisible. Causal knowledge is elicited by stimulating the children to expose real-life objects (e.g., candles) to the sensor node. The playful experience is amplified by letting children play in pairs. The game was evaluated using the Wizard of Oz method in a sample of 27 children aged between 7 and 11 years. The results show that the proposed game, in addition to improving children’s knowledge about indoor air pollution, is also perceived by them as easy to use and a useful learning tool that they would like to continue using, even in other educational contexts.info:eu-repo/semantics/publishedVersio
Carbon stock change due to land use in argisols on pernambucano-brazillan semiarid
Carbon stored in soils depends on the type of vegetation and management applied. Native vegetation removed for the installation of pastures and grassland affects carbon stocks in the soil.Argisols are one the most used type of soils in agriculture, due its excellent physical and chemical characteristics. Asses carbon stored in these soils under different land uses and understand the dynamics of the C element in ecosystems is important. In this study we examined four types of vegetation cover in three sites on interior of Pernambuco state in Brazil. Trenches of 0.7 x 0.7 m with 0.4 m deep were open and soil samples were collected at 0-10, 10-20, 20-30 and 30-40 cm layers to determine carbon content and soil density. Carbon concentrations were determined by dry combustion using a CHN elemental analyzer (CN TruSpec LECO® 2006, St. Joseph, USA). Land use change altered carbon stocks in soil, dense caatinga presented higher stocks than open caatinga, grassland and agriculture. In the 0-10 cm layer expressed biggest difference in C stocks in different vegetation cover
ACOUSTIC CAVITIES DESIGN PROCEDURES
Combustion instability is recognized as one of the major problems frequently faced by engineers during the development of either liquid or solid propellant rocket engines. The performance of the engine can be highly affected by these high frequencies instabilities, possibly leading the rocket to an explosion. The main goal while studying combustion chambers instability, either by means of baffles or acoustic absorbers, is to achieve the stability needed using the simplest possible manner. This paper has the purpose of studying combustion chambers instabilities, as well as the design of acoustic absorbers capable of reducing their eigenfrequencies. Damping systems act on the chamber eigenfrequency, which has to be, therefore, previously known
Asteroids seen by JWST-MIRI: Radiometric Size, Distance and Orbit Constraints
Infrared measurements of asteroids are crucial for the determination of
physical and thermal properties of individual objects, and for the
understanding of the small-body populations in the solar system as a whole. But
standard radiometric methods can only be applied if the orbit of an object is
known, hence its position at the time of the observation. We present MIRI
observations of the outer-belt asteroid 10920 and an unknown object, detected
in all 9 MIRI bands in close proximity to 10920. We developed a new method
"STM-ORBIT" to interpret the multi-band measurements without knowing the
object's true location. The method leads to a confirmation of radiometric
size-albedo solution for 10920 and puts constraints on the asteroid's location
and orbit in agreement with its true orbit. Groundbased lightcurve observations
of 10920, combined with Gaia data, indicate a very elongated object (a/b >=
1.5), with a spin-pole at (l, b) = (178{\deg}, 81{\deg}), and a rotation period
of 4.861191 h. A thermophysical study leads to a size of 14.5 - 16.5 km, a
geometric albedo between 0.05 and 0.10, and a thermal inertia in the range 9 to
35 Jm-2s-0.5K-1. For the newly discovered MIRI object, the STM-ORBIT method
revealed a size of 100-230 m. The new asteroid must be on a very
low-inclination orbit and it was located in the inner main-belt region during
JWST observations. A beaming parameter {\eta} larger than 1.0 would push the
size even below 100 meter, a main-belt regime which escaped IR detections so
far. These kind of MIRI observations can therefore contribute to formation and
evolution studies via classical size-frequency studies which are currently
limited to objects larger than about one kilometer in size. We estimate that
MIRI frames with pointings close to the ecliptic and only short integration
times of a few seconds will always include a few asteroids, most of them will
be unknown objects.Comment: 17 pages, 10 figures, 4 tables, accepted for A&A publication on Nov
22, 202
A MegaCam Survey of Outer Halo Satellites. VI: The Spatially Resolved Star Formation History of the Carina Dwarf Spheroidal Galaxy
We present the spatially resolved star formation history (SFH) of the Carina
dwarf spheroidal galaxy, obtained from deep, wide-field g,r imaging and a
metallicity distribution from the literature. Our photometry covers
deg, reaching up to times the half-light radius of Carina with a
completeness higher than at , more than one magnitude fainter
than the oldest turnoff. This is the first time a combination of depth and
coverage of this quality has been used to derive the SFH of Carina, enabling us
to trace its different populations with unprecedented accuracy. We find that
Carina's SFH consists of two episodes well separated by a star formation
temporal gap. These episodes occurred at old ( Gyr) and intermediate
(- Gyr) ages. Our measurements show that the old episode comprises the
majority of the population, accounting for of the stellar mass
within times the King tidal radius, while the total stellar mass derived
for Carina is , and the stellar
mass-to-light ratio . The SFH derived is consistent with no recent
star formation which hints that the observed blue plume is due to blue
stragglers. We conclude that the SFH of Carina evolved independently of the
tidal field of the Milky Way, since the frequency and duration of its star
formation events do not correlate with its orbital parameters. This result is
supported by the age/metallicity relation observed in Carina, and the gradients
calculated indicating that outer regions are older and more metal poor.Comment: Accepted in ApJ (22 pages, 13 figures
Aproveitamento da borra de açaà para produção de biscoitos.
Este trabalho avaliou a farinha da borra de açaà na substituição parcial da farinha de trigo na formulação de biscoito
Ctenarytaina eucalypti (Maskell, 1890) (Hemiptera, Psyllidae) em eucaliptos no Brasil.
É reportada a ocorrência do psilÃdeo Ctenarytaina eucaypti (Maskell, 1890) (Hemiptera, Psyllidae), praga de origem Australiana, recentemente observada em Colombo, Paraná. Este psilÃdeo foi observado causando danos em folhas e brotações de mudas de E. dunnii. São relatados os danos, distribuição geográfica, biologia e control
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