Monitoring environmental quality in urban areas is an important issue offering possibilities to control and improve urban habitat quality as well as to avoid adverse effects on human health. A tree ...leaf reflectance-based bio-monitoring method was used to assess the urban habitat quality of two contrasting habitat classes in the city of Gent (Belgium). As test trees, two Tilia species were selected. Custom made Matlab code is applied to process the measurements of leaf reflectance. This enables the discrimination between polluted and less polluted habitats. The results elicit, that leaf reflectance in the PAR range, as well as the NDAI (Normalised Difference Asymmetry index) are species dependent while Dorsiventral Leaf Reflectance Correlation (DLRC) seems to be independent of species. Therefore the assessment of urban habitat quality is perfectly feasible using leaf reflectance, when taking account of the species specificity of tree leaf physiological and structural responses to habitat quality.
► Leaf structure and physiological changes in urban habitat classes. ► Leaf reflectance of Linden tree species is affected by urban habitat quality. ► Species dependent leaf reflectance changes due to urban habitat pollution. ► Dorsiventral leaf reflectance properties for assessing habitat quality. ► High capability of the leaf reflectance technique for assessing habitat quality.
Leaf reflectance and dorsiventral properties of Linden tree species can be used to assess urban habitat quality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract The aim of this study was to compare the three-dimensional (3D) imaging accuracy between a digital stereophotogrammetry device and a projection moiré profilometry setup using anatomical ...models in conjunction with surface matching software. Twenty-two 3D surface models of the middle third of the face derived from computed tomography (CT) scans were used to fabricate photopolymer models by rapid prototyping. These were digitized using digital stereophotogrammetry and projection moiré profilometry. The 3D surface models acquired were compared for shape differences with the original CT models using surface matching software. Global registration between each pair of corresponding models was carried out using an iterative closest point algorithm. The mean surface deviations following registration were used to calculate Bland–Altman limits of agreement between the two methods. The distributions of measured surface differences were used to calculate L-moments. Paired t -tests were carried out for hypothesis testing. Correlation between difference and mean was −0.3, and 95% limits of agreement were −0.084 mm and 0.064 mm. No statistically significant differences in mean measurement error (L1 moments) were observed ( P = 0.1882). The experimental moiré profilometry setup employed produced 3D models of facial anatomy of comparable accuracy to a widely used commercialized digital stereophotogrammetry device.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
•Impact of urban habitat quality on leaf injuries was estimated by leaf reflectance.•The quantification of leaf injury can be performed with a commercial RGB camera.•Leaf injury properties of Tilia ...sp. can be linked to the urban habitat quality.•At the most polluted urban habitat leaf injury reached the highest values.•Injured leaf area reflectance is a suitable indicator to assess urban habitat quality.
Urban habitat quality and its effects on humans and the environment are of great concern in regard to human and vegetation health security, urban planning and habitat management. Different methods have been used to monitor habitat quality. Certain of these methods are expensive, labor-intensive, time-consuming and problematic to extrapolate to a larger spatial region of interest.
In this paper, we evaluate a non-destructive and low-cost method to assess urban habitat quality. The method is based on quantifying leaf injury symptoms using imagery obtained with a digital camera. The leaves of lime trees (Tilia sp.), split up into two different groups of with and without trichomes, were sampled in Ghent (Belgium) during the summer of 2009. Leaf sampling was conducted in four different urban habitats, corresponding to four land use classes that are characterized by different degrees of environmental pollution. Leaf necrotic spots, as well as chlorotic patches, were selected as indicators of leaf injury. Our results reveal that the density of necrotic spots, as well as chlorotic patch areas, significantly increase in industrial land use zones compared with other land use classes for both Tilia sp. groups. The injured leaf area reflectance significantly increased for the camera RGB bands of industrial zones compared with the three other types of habitats. These results indicate that injured leaf area reflectance is a sensitive indicator that can be quickly determined. Thus, this technique enables fast, site-based bio-monitoring of urban habitats compared with the determination of leaf parameters, such as leaf density, area or the number of (necrotic and chlorotic) leaf spots as other indicators of leaf injury.
We illustrated that the injured leaf area reflectance, as determined using leaf surface reflectance, and extracting symptoms is a novel, as well as practical, approach to assessing urban habitat quality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
We performed a detailed study of the timing performance of the LHCb VELO Timepix3 Telescope with a 180 GeV/c mixed hadron beam at the CERN SPS. A twofold method was developed to improve the ...resolution of single-plane time measurements, resulting in a more precise overall track time measurement. The first step uses spatial information of reconstructed tracks in combination with the measured signal charge in the sensor to correct for a mixture of different effects: variations in charge carrier drift time; variations in signal induction, which are the result of a non-uniform weighting field in the pixels; and lastly, timewalk in the analog front-end. The second step corrects for systematic timing offsets in Timepix3 that vary from −2 to 2 ns. By applying this method, we improved the track time resolution from 438(16) ps to 276(4) ps.
Computer modeling of middle ear mechanics is an important tool to investigate its complex behavior, but correct mechanical and elastic parameters are needed to obtain realistic simulations. A ...possible way to determine eardrum elasticity in situ is the use of point indentation measurements. The eardrum is, however, a small fragile membrane, so a non-contacting high-resolution technique is needed to measure the shape change caused by point indentation. We have developed a projection moiré interferometer combined with an indentation actuator and a high-resolution force sensor. The apparatus applies deformations up to 1
mm with a resolution of
1
μ
m
, while the indentation force is measured with a resolution better than 1
mN. The moiré setup delivers height data on
512
×
512
points through phase-shifting, with a height resolution of
15
μ
m
. Shape recordings are made on a rabbit eardrum at different indentation distances, and indentation force is recorded simultaneously.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The utriculo-endolymphatic valve was discovered by Bast in 1928. The function of Bast’s valve is still unclear. By means of orthogonal-plane fluorescence optical sectioning (OPFOS) microscopy ...3D-reconstructions of the valve and its surrounding region are depicted. The shape of the duct at the utricular side is that of a flattened funnel. In the direction of the endolymphatic duct and sac this funnel runs into a very narrow duct. The valve itself has a rigid ‘arch-like’ configuration. The opposing thin, one cell-layer thick, utricular membrane is highly compliant. We propose that opening and closure of the valve occurs through movement of the flexible base/utricular membrane away from and toward the relatively rigid valve lip.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The VeloPix ASIC Poikela, T.; Ballabriga, R.; Buytaert, J. ...
Journal of instrumentation,
01/2017, Volume:
12, Issue:
1
Journal Article
Peer reviewed
Open access
VeloPix, a 130 nm CMOS technology chip with data driven and zero suppressed readout, will be used as a readout chip for the hybrid pixel system of the LHCb Vertex Locator (VELO) upgrade. The upgrade, ...scheduled for LHC Run-3, will enable the experiment to be read out at 40 MHz in trigger-less mode, with event selection being performed in the CPU farm. The highest occupancy ASICs will experience rates of more than 900 Mhits/s, and the closest pixels are 5.1 mm from the LHC beams. This paper will present the VeloPix ASIC along with the first test results without a sensor.
When studying complex vibrations, simultaneous measurements at several points are indispensable if one is dealing with objects whose vibrational behavior is not guaranteed to be stable over longer ...periods of time, such as biological specimens, micro-mechanical elements or objects characterized by nearly resonant normal modes with different vibrational patterns. Obviously, both amplitude and phase need to be measured at each point to obtain a full characterization of the vibration. We introduce birefringent beam displacers as a highly efficient beam multiplying method to create a system of four heterodyne interferometers operating in parallel from a single laser source. The design and the performance characteristics (resolution, cross-talk) of the instrument will be discussed. The system revealed the existence of running vibrational modes on an electrically driven plate clamped along its outer edge.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
10.
VeloPix ASIC development for LHCb VELO upgrade van Beuzekom, M.; Buytaert, J.; Campbell, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Volume:
731
Journal Article
Peer reviewed
The upgrade of the LHCb experiment, planned for 2018, will transform the readout of the entire experiment to a triggerless system operating at 40MHz. All data reduction algorithms will be run in a ...high level software farm, and will have access to event information from all subdetectors. This approach will give great power and flexibility in accessing the physics channels of interest in the future, in particular the identification of flavour tagged events with displaced vertices. The data acquisition and front end electronics systems require significant modification to cope with the enormous throughput of data. For the silicon vertex locator (VELO) a dedicated development is underway for a new ASIC, VeloPix, which will be a derivative of the Timepix/Medipix family of chips. The chip will be radiation hard and be able to cope with pixel hit rates of above 500MHz, highly non-uniformly distributed over the 2cm2 chip area. The chip will incorporate local intelligence in the pixels for time-over-threshold measurements, time-stamping and sparse readout. It must in addition be low power, radiation hard, and immune to single event upsets. In order to cope with the datarates and use the pixel area most effectively, an on-chip data compression scheme will integrated. This paper will describe the requirements of the LHCb VELO upgrade, and give an overview of the digital architecture being developed specifically for the readout chip.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
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