469,682 research outputs found
The passive operating mode of the linear optical gesture sensor
The study evaluates the influence of natural light conditions on the
effectiveness of the linear optical gesture sensor, working in the presence of
ambient light only (passive mode). The orientations of the device in reference
to the light source were modified in order to verify the sensitivity of the
sensor. A criterion for the differentiation between two states: "possible
gesture" and "no gesture" was proposed. Additionally, different light
conditions and possible features were investigated, relevant for the decision
of switching between the passive and active modes of the device. The criterion
was evaluated based on the specificity and sensitivity analysis of the binary
ambient light condition classifier. The elaborated classifier predicts ambient
light conditions with the accuracy of 85.15%. Understanding the light
conditions, the hand pose can be detected. The achieved accuracy of the hand
poses classifier trained on the data obtained in the passive mode in favorable
light conditions was 98.76%. It was also shown that the passive operating mode
of the linear gesture sensor reduces the total energy consumption by 93.34%,
resulting in 0.132 mA. It was concluded that optical linear sensor could be
efficiently used in various lighting conditions.Comment: 10 pages, 14 figure
Community-level response of coastal microbial biofilms to ocean acidification in a natural carbon dioxide vent ecosystem.
The version on PEARL: Corrected proofs are Articles in Press that contain the authors' corrections. Final citation details, e.g., volume/issue number, publication year and page numbers, still need to be added and the text might change before final publication. Although corrected proofs do not have all bibliographic details available yet, they can already be cited using the year of online publication and the DOI , as follows: author(s), article title, journal (year), DOIThe impacts of ocean acidification on coastal biofilms are poorly understood. Carbon dioxide vent areas provide an opportunity to make predictions about the impacts of ocean acidification. We compared biofilms that colonised glass slides in areas exposed to ambient and elevated levels of pCO(2) along a coastal pH gradient, with biofilms grown at ambient and reduced light levels. Biofilm production was highest under ambient light levels, but under both light regimes biofilm production was enhanced in seawater with high pCO(2). Uronic acids are a component of biofilms and increased significantly with high pCO(2). Bacteria and Eukarya denaturing gradient gel electrophoresis profile analysis showed clear differences in the structures of ambient and reduced light biofilm communities, and biofilms grown at high pCO(2) compared with ambient conditions. This study characterises biofilm response to natural seabed CO(2) seeps and provides a baseline understanding of how coastal ecosystems may respond to increased pCO(2) levels
UV detector monitors organic contamination of optical surfaces
Silicon carbide, insensitive to visible light, is used in photodetectors. System contamination can be monitored during the normal operation without interference to the operator, and without shielding from ambient light
Exposure interlock for oscilloscope cameras
An exposure interlock has been developed for oscilloscope cameras which cuts off ambient light from the oscilloscope screen before the shutter of the camera is tripped. A flap is provided which may be selectively positioned to an open position which enables viewing of the oscilloscope screen and a closed position which cuts off the oscilloscope screen from view and simultaneously cuts off ambient light from the oscilloscope screen. A mechanical interlock is provided between the flap to be activated to its closed position before the camera shutter is tripped, thereby preventing overexposure of the film
Dew-worms in white nights: High-latitude light constrains earthworm (Lumbricus terrestris) behaviour at the soil surface
Soil is an effective barrier to light penetration that limits the direct influence of light on belowground organisms. Variation in aboveground light conditions, however, is important to soil-dwelling animals that are periodically active on the soil surface. A prime example is the earthworm Lumbricus terrestris L. (the dew-worm), an ecosystem engineer that emerges nocturnally on the soil surface. In the summer, the northernmost populations of L. terrestris are exposed to a time interval with no daily dark period. During a two-week period preceding the summer solstice, we studied the constraints that boreal night illumination imposes on L. terrestris surface activity by comparing their behaviour under ambient light with artificially-induced darkness. Looking for evidence of geographical divergence in light response, we compared the behaviour of native L. terrestris (Jokioinen, SāW Finland; 60Ā°48ā²N) with two markedly more southern populations, from Preston (Lancashire, UK; 53Ā°47ā²N) and Coshocton (Ohio, USA; 40Ā°22ā²N) where the nights have a period of darkness throughout the year (total latitudinal range ca. 2300 km). Under ambient light conditions, L. terrestris emergence on the soil surface was diminished by half compared with the darkened treatment and it peaked at the darkest period of the night. Also mating rate decreased considerably under ambient light. The native dew-worms were generally the most active under ambient light. They emerged earlier in the evening and ceased their activity later in the morning than dew-worms from the two more southerly populations. The differences in behaviour were, however, significant mainly between native and UK dew-worms. In the darkened treatment, the behaviour of the three earthworm origins did not differ. Under the experimental conditions light condition was the dominant environmental factor controlling surface activity, but elevated night-time air temperature and humidity also encouraged dew-worm emergence without discernible differences among geographical origins. Our results show, that in boreal summer, the high level of night illumination strongly limits soil-surface activity of dew-worms. Considering the important regulatory role of L. terrestris in many ecosystem processes, this can have significant corollaries in dew-worm impacts on the environment. Although evidence for geographical differentiation in behaviour was obtained, the results point to phenotypic flexibility in L. terrestris light response
The Effect of Ambient Temperature on Cold Start Urban Traffic Emissions for a Real World SI Car
The influence of ambient temperature on exhaust
emissions for an instrumented Euro 1 SI car was
determined. A real world test cycle was used, based on
an urban drive cycle that was similar to the ECE urban
drive cycle. It was based on four laps of a street circuit
and an emissions sample bag was taken for each lap.
The bag for the first lap was for the cold start emissions.
An in-vehicle direct exhaust dual bag sampling
technique was used to simultaneously collect exhaust
samples upstream and downstream of the three-way
catalyst (TWC). The cold start tests were conducted
over a year, with ambient temperatures ranging from ā
2Ā°C to 32Ā°C. The exhaust system was instrumented with
thermocouples so that the catalyst light off temperature
could be determined. The results showed that CO
emissions for the cold start were reduced by a factor of
8 downstream of catalyst when ambient temperature
rose from -2Ā°C to 32Ā°C, the corresponding hydrocarbon
emissions were reduced by a factor of 4. There was no
clear relationship between NOx emissions and ambient
temperature. For subsequent laps of the test circuit the
reduction of CO and HC emissions as a function of
ambient temperature was lower. The time for catalyst
light off increased by 50% as the ambient temperature
was reduced. The results show that the vehicle used is
unlikely to meet the new ā 7oC cold start CO emission
regulations
The effect of ambient temperature on cold start urban traffic emissions for a real world SI car
The influence of ambient temperature on exhaust
emissions for an instrumented Euro 1 SI car was
determined. A real world test cycle was used, based on
an urban drive cycle that was similar to the ECE urban
drive cycle. It was based on four laps of a street circuit
and an emissions sample bag was taken for each lap.
The bag for the first lap was for the cold start emissions.
An in-vehicle direct exhaust dual bag sampling
technique was used to simultaneously collect exhaust
samples upstream and downstream of the three-way
catalyst (TWC). The cold start tests were conducted
over a year, with ambient temperatures ranging from ā
2Ā°C to 32Ā°C. The exhaust system was instrumented with
thermocouples so that the catalyst light off temperature
could be determined. The results showed that CO
emissions for the cold start were reduced by a factor of
8 downstream of catalyst when ambient temperature
rose from -2Ā°C to 32Ā°C, the corresponding hydrocarbon
emissions were reduced by a factor of 4. There was no
clear relationship between NOx emissions and ambient
temperature. For subsequent laps of the test circuit the
reduction of CO and HC emissions as a function of
ambient temperature was lower. The time for catalyst
light off increased by 50% as the ambient temperature
was reduced. The results show that the vehicle used is
unlikely to meet the new ā 7oC cold start CO emission
regulations
Strong antenna-enhanced fluorescence of a single light-harvesting complex shows photon antibunching
The nature of the highly efficient energy transfer in photosynthetic light-harvesting complexes is a subject of intense research. Unfortunately, the low fluorescence efficiency and limited photostability hampers the study of individual light-harvesting complexes at ambient conditions. Here we demonstrate an over 500-fold fluorescence enhancement of light-harvesting complex 2 (LH2) at the single-molecule level by coupling to a gold nanoantenna. The resonant antenna produces an excitation enhancement of circa 100 times and a fluorescence lifetime shortening to ~\n20āps. The radiative rate enhancement results in a 5.5-fold-improved fluorescence quantum efficiency. Exploiting the unique brightness, we have recorded the first photon antibunching of a single light-harvesting complex under ambient conditions, showing that the 27 bacteriochlorophylls coordinated by LH2 act as a non-classical single-photon emitter. The presented bright antenna-enhanced LH2 emission is a highly promising system to study energy transfer and the role of quantum coherence at the level of single complexes
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